Hose water valve is to obtain the insurance authorized by State Intellectual Property Office of the utility model patent. Its main function is to achieve not turn the outlet water hoses to reach to save water, reduce waste and prevent water hose up, crack and fall off purposes.
Water hose valve can be directly applied to the insurance of all need to use long-distance water supply hose industry. Such as washing lines, plants (equipment cleaning), street facade, building cleaning, gardening irrigation, washing buses, the construction industry and the general families. Specific use is: When the water pressure to reach 0.15K pa or more, you can directly install the switch in tap water, "water hose Insurance valve," and then hose connected to the valve on the outlet can be achieved in the long-distance not turn water hoses up and not worry about cracking or joints off in order to achieve the purpose of saving water
This type of insurance valves low price, efficiency and reliable, simple structure, less wearing parts, easy installation, water-saving effect is remarkable.
ball valve Trunnion Mounted Ball Valve Floating Ball Valve Top Entry Ball Valve Three way ball valve V Type Ball Valve
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Thursday, September 30, 2010
Tuesday, September 28, 2010
Solenoid valve and the development of new technical features of the problem
Solenoid valve as an automatic instrument actuator, the amount of a sharp increase in recent years. This paper analyzes the main characteristics of the solenoid valve, and focuses on the application's point of view, on the domestic development of mature technologies for a brief overview of, respectively, in the streamlining, intelligence, common and dedicated direction of study, and a little of the impact of electromagnetic valve technology for the social dimension of development are discussed.
(1) no leakage plugging, easy to control with the leakage, the use of security.
Internal and external leakage is a factor likely to affect safety. Other controlled valve stem out usually by electrical, pneumatic, hydraulic spool executive body to control the rotation or move. This needs to be tackled by stem seal leakage caused by problems outside; only electromagnetic solenoid valve is sealed in the following works for the magnetic core within the casing to complete, there is no dynamic seals, the leakage can easily block. Electric torque control valve is not easy, prone to leakage, and even pull off the head stem; the structure type solenoid valve with easy to control the leakage until zero. Therefore, the use of special safety solenoid valve, in particular, applicable to corrosive, toxic or high temperature media.
(2) the system is simple, will take computers, low cost him.
Solenoid valve itself simple structure, low prices, compared to other types of control valve actuators, such as easy installation and maintenance. More significant is the composition of the automatic control system is much simpler, much lower price. Solenoid valve is switched due to signal control, and industrial control computer is very convenient to connect. Universal in today's computers, an era of declining prices, the solenoid valve on the more obvious advantages.
(3) Action Express, power tiny, lightweight form factor.
Solenoid valve response time can be as short as a few milliseconds, even if the pilot-type solenoid valve can be controlled within a few dozen milliseconds. As the self-loop, other than more responsive control valve. Properly designed coil of solenoid valve power consumption is very low, an energy-saving products; action could also be just the trigger to automatically maintain valve position, usually is not power. Small size solenoid valve, saving space and beautiful light. valve ball valve gate valve check valve globe valve butterfly valve
We can offer more Knife Gate Valve Information.If you need us according your spcification to produce the Knife Gate Valve .
Need, please e-mail to valve401@gmail.com
(1) no leakage plugging, easy to control with the leakage, the use of security.
Internal and external leakage is a factor likely to affect safety. Other controlled valve stem out usually by electrical, pneumatic, hydraulic spool executive body to control the rotation or move. This needs to be tackled by stem seal leakage caused by problems outside; only electromagnetic solenoid valve is sealed in the following works for the magnetic core within the casing to complete, there is no dynamic seals, the leakage can easily block. Electric torque control valve is not easy, prone to leakage, and even pull off the head stem; the structure type solenoid valve with easy to control the leakage until zero. Therefore, the use of special safety solenoid valve, in particular, applicable to corrosive, toxic or high temperature media.
(2) the system is simple, will take computers, low cost him.
Solenoid valve itself simple structure, low prices, compared to other types of control valve actuators, such as easy installation and maintenance. More significant is the composition of the automatic control system is much simpler, much lower price. Solenoid valve is switched due to signal control, and industrial control computer is very convenient to connect. Universal in today's computers, an era of declining prices, the solenoid valve on the more obvious advantages.
(3) Action Express, power tiny, lightweight form factor.
Solenoid valve response time can be as short as a few milliseconds, even if the pilot-type solenoid valve can be controlled within a few dozen milliseconds. As the self-loop, other than more responsive control valve. Properly designed coil of solenoid valve power consumption is very low, an energy-saving products; action could also be just the trigger to automatically maintain valve position, usually is not power. Small size solenoid valve, saving space and beautiful light. valve ball valve gate valve check valve globe valve butterfly valve
We can offer more Knife Gate Valve Information.If you need us according your spcification to produce the Knife Gate Valve .
Need, please e-mail to valve401@gmail.com
Agricultural Machinery Pressure Control Valve Failure and test methods
Agricultural machinery, hydraulic system, the pressure valve is used more often in a class of components, the pressure valve a sudden failure will directly affect the normal operation of machinery and equipment, this paper points the pressure valve failure reasons and examples of the pressure valve testing methods.
1. The common cause of failure
(1) hydraulic valve core and valve body when using the continuous generation of wear and tear, allowing part size, shape and surface quality changes.
(2) the balance of hydraulic valve springs, valve core and valve seat, in the long run to work under variable loads, resulting in fatigue and crack, resulting in spring, break, or the valve seat sealing surface, peeling off, damaged.
(3) hydraulic valve parts processing residues and use of residual stress in the external load stress, the material yield strength of more than spare parts, spare parts deformation.
(4) hydraulic oil mixed with water or too much acid, using a longer time, the corrosion of hydraulic valve parts to lose their accuracy.
(5) with the valve spool suites liquid radial force imbalance, ultimately spool valve comprising a wall pressure to the clamping phenomenon occurs.
(6) in the hydraulic valve manufacture or repair, did not meet the technical requirements provided; or part lack of good care, rust, mixed with dirt and so on.
2. For example, test methods
Pressure valves including relief valves, pressure reducing valve and sequence valve, this paper valve pressure relief valve as an example shows the test items and testing methods. Pressure valve test can be conducted in a dedicated test rig can also be carried out in an integrated test bed.
(1) the scope and the pressure regulator stability test. Regulating valves were tested hand wheel adjustment, from fully open to fully closed, and then to fully open from the pressure gauge shows the pressure rise and fall as well as voltage range. Pressure gauge pointer should be a smooth rise and fall voltage range should meet the required voltage range at the highest pressure, pressure fluctuation is not to exceed the specified value.
(2) within the leakage test. Regulating valve adjustment by hand wheel to full closed position, adjustable overflow valve as being the maximum pressure test valve, and then try regulating valve hand wheel adjustment, so that subjects were measured within the overflow valve leakage.
(3) The unloading stress testing. The relief valve remote control port access fuel tank, so that valves were tested by examining the flow, measuring the pressure relief valve in and out of the oil port, the difference shall be unloading valve pressure test.
(4) pressure loss testing. Regulating valve adjustment were tested hand wheel to full release and make valves were tested by examining the flow, measured by the pressure gauge the pressure relief valve in and out of the oil port, the difference shall be test valve pressure loss.
(5) open and close feature tests. Close overflow safety valve, regulating valve were tested to the maximum pressure, regulate blood pressure overflow valve make the system gradually, when the valve is closed down by the pressure test subjects were measured at excess flow valves. Adjustable overflow safety valve, pilot valve has been no overflow from the beginning to make the system a gradual step-up, when the pilot valve has been opened up to stress, measured by the excess flow valve. ball valve Trunnion Mounted Ball Valve Floating Ball Valve Top Entry Ball Valve Three way ball valve V Type Ball Valve
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1. The common cause of failure
(1) hydraulic valve core and valve body when using the continuous generation of wear and tear, allowing part size, shape and surface quality changes.
(2) the balance of hydraulic valve springs, valve core and valve seat, in the long run to work under variable loads, resulting in fatigue and crack, resulting in spring, break, or the valve seat sealing surface, peeling off, damaged.
(3) hydraulic valve parts processing residues and use of residual stress in the external load stress, the material yield strength of more than spare parts, spare parts deformation.
(4) hydraulic oil mixed with water or too much acid, using a longer time, the corrosion of hydraulic valve parts to lose their accuracy.
(5) with the valve spool suites liquid radial force imbalance, ultimately spool valve comprising a wall pressure to the clamping phenomenon occurs.
(6) in the hydraulic valve manufacture or repair, did not meet the technical requirements provided; or part lack of good care, rust, mixed with dirt and so on.
2. For example, test methods
Pressure valves including relief valves, pressure reducing valve and sequence valve, this paper valve pressure relief valve as an example shows the test items and testing methods. Pressure valve test can be conducted in a dedicated test rig can also be carried out in an integrated test bed.
(1) the scope and the pressure regulator stability test. Regulating valves were tested hand wheel adjustment, from fully open to fully closed, and then to fully open from the pressure gauge shows the pressure rise and fall as well as voltage range. Pressure gauge pointer should be a smooth rise and fall voltage range should meet the required voltage range at the highest pressure, pressure fluctuation is not to exceed the specified value.
(2) within the leakage test. Regulating valve adjustment by hand wheel to full closed position, adjustable overflow valve as being the maximum pressure test valve, and then try regulating valve hand wheel adjustment, so that subjects were measured within the overflow valve leakage.
(3) The unloading stress testing. The relief valve remote control port access fuel tank, so that valves were tested by examining the flow, measuring the pressure relief valve in and out of the oil port, the difference shall be unloading valve pressure test.
(4) pressure loss testing. Regulating valve adjustment were tested hand wheel to full release and make valves were tested by examining the flow, measured by the pressure gauge the pressure relief valve in and out of the oil port, the difference shall be test valve pressure loss.
(5) open and close feature tests. Close overflow safety valve, regulating valve were tested to the maximum pressure, regulate blood pressure overflow valve make the system gradually, when the valve is closed down by the pressure test subjects were measured at excess flow valves. Adjustable overflow safety valve, pilot valve has been no overflow from the beginning to make the system a gradual step-up, when the pilot valve has been opened up to stress, measured by the excess flow valve. ball valve Trunnion Mounted Ball Valve Floating Ball Valve Top Entry Ball Valve Three way ball valve V Type Ball Valve
We can offer more Knife Gate Valve Information.If you need us according your spcification to produce the Knife Gate Valve .
Need, please e-mail to valve401@gmail.com
Affect the safe operation of the factors regulating valve and Countermeasures (Part One)
1, Introduction
In the higher degree of automation of chemical control system, regulating valve as the implementation of automatic adjustment system, the terminal device to receive control signals to achieve the regulation of chemical processes. It is directly related to the sensitivity of the action-conditioning systems quality. According to the site of about 70% of the actual statistics of the failures come from regulating valve. Therefore, routine maintenance review and analyze the impact the safe operation of the factors regulating valve and Countermeasures
2, card blocking
Valve recurring problem is that card blocked, often appear in the new transport system and the overhaul of investment put into operation in the initial stage, due to pipe welding slag, rust, etc. at the cutting mouth, oriented so that part of blockage caused by poor circulation media, or regulating valve repair in the tight packing, resulting in increased friction, leading to large-signal small-signal non-action motion overshoot phenomenon. |
Troubleshooting: You can quickly open, off-line or adjust the valve, vice, so that dirt from the Vice-line or adjust the valve was washed medium run. Another way to stem tube clamp tight, plus the signal pressure in the case, the positive and negative force rotating stem, so that spool flash card office. If it is not an increase of gas pressure to increase the drive power source has repeatedly moved up and down several times, you can solve the problem. Should the motion not, it would take the disintegration of treatment.
3, leakage
3.1 valve leakage, valve stem length of the discomfort. Air to open valve, stem long stem up (or down) the distance is not enough, resulting in gaps between the valve core and valve seat can not be full access, leading to lax customs and internal leakage. Similarly, gas off valve stem is too short, resulting in gaps between the valve core and valve seat can not be full access, leading to lax customs and internal leakage.
Solution: should be shortened (or extended) regulating valve stem so that the length of the right valve so that it no longer internal leakage.
3.2 Packing leak
Packing into stuffing after the axial pressure imposed by the gland. Because the plastic filler to produce a radial force, and close contact with the valve stem, but this contact is not very uniform. Some parts of the loose contact with some parts of the tight contact with, or even no contact at some parts. Regulating valve in the use process, the stem with the filling between the relative movement, this movement is called axial movement. The use of the process, with the high-temperature, high pressure and permeability of fluid medium strong, regulating valve packing leak letter is part of larger phenomena. Is mainly due to leakage caused by filler interface leakage, will appear for the textile and packing leakage (pressure medium along the filler-gap between the small outward leak). The interface between the stem and the packing leakage is due to the gradual attenuation of the contact pressure filler, filler causes such as their own aging, when the pressure medium will be along the contact between the filler and the valve stem outward leakage gap.
Countermeasures: In order to facilitate the filler loading, in the stuffing to the top chamfer, in the stuffing box placed at the bottom of the smaller gap erosion-resistant metal protection ring (with the contact surface can not fill slope) in order to prevent the fill material was medium pressure introduced. Stuffing box packing contact with the ministries and part of the metal surface to be finished, in order to improve the surface finish and reduce packing wear and tear. Flexible graphite packing selected because of their good gas tightness, the friction is small, changes after long-term use of small, wear the burning of a small, maintenance easy, gland bolts re-tightened after the friction does not change, pressure and resistance heat well, is not within the medium erosion, with the stem and the stuffing does not occur within the contact with the metal pitting or corrosion. In this way, the effective protection of the valve stem seal stuffing to ensure the reliability of sealing packing and long-term.
ball valve Trunnion Mounted Ball Valve Floating Ball Valve Top Entry Ball Valve Three way ball valve V Type Ball Valve
We can offer more Knife Gate Valve Information.If you need us according your spcification to produce the Knife Gate Valve .
Need, please e-mail to valve401@gmail.com
In the higher degree of automation of chemical control system, regulating valve as the implementation of automatic adjustment system, the terminal device to receive control signals to achieve the regulation of chemical processes. It is directly related to the sensitivity of the action-conditioning systems quality. According to the site of about 70% of the actual statistics of the failures come from regulating valve. Therefore, routine maintenance review and analyze the impact the safe operation of the factors regulating valve and Countermeasures
2, card blocking
Valve recurring problem is that card blocked, often appear in the new transport system and the overhaul of investment put into operation in the initial stage, due to pipe welding slag, rust, etc. at the cutting mouth, oriented so that part of blockage caused by poor circulation media, or regulating valve repair in the tight packing, resulting in increased friction, leading to large-signal small-signal non-action motion overshoot phenomenon. |
Troubleshooting: You can quickly open, off-line or adjust the valve, vice, so that dirt from the Vice-line or adjust the valve was washed medium run. Another way to stem tube clamp tight, plus the signal pressure in the case, the positive and negative force rotating stem, so that spool flash card office. If it is not an increase of gas pressure to increase the drive power source has repeatedly moved up and down several times, you can solve the problem. Should the motion not, it would take the disintegration of treatment.
3, leakage
3.1 valve leakage, valve stem length of the discomfort. Air to open valve, stem long stem up (or down) the distance is not enough, resulting in gaps between the valve core and valve seat can not be full access, leading to lax customs and internal leakage. Similarly, gas off valve stem is too short, resulting in gaps between the valve core and valve seat can not be full access, leading to lax customs and internal leakage.
Solution: should be shortened (or extended) regulating valve stem so that the length of the right valve so that it no longer internal leakage.
3.2 Packing leak
Packing into stuffing after the axial pressure imposed by the gland. Because the plastic filler to produce a radial force, and close contact with the valve stem, but this contact is not very uniform. Some parts of the loose contact with some parts of the tight contact with, or even no contact at some parts. Regulating valve in the use process, the stem with the filling between the relative movement, this movement is called axial movement. The use of the process, with the high-temperature, high pressure and permeability of fluid medium strong, regulating valve packing leak letter is part of larger phenomena. Is mainly due to leakage caused by filler interface leakage, will appear for the textile and packing leakage (pressure medium along the filler-gap between the small outward leak). The interface between the stem and the packing leakage is due to the gradual attenuation of the contact pressure filler, filler causes such as their own aging, when the pressure medium will be along the contact between the filler and the valve stem outward leakage gap.
Countermeasures: In order to facilitate the filler loading, in the stuffing to the top chamfer, in the stuffing box placed at the bottom of the smaller gap erosion-resistant metal protection ring (with the contact surface can not fill slope) in order to prevent the fill material was medium pressure introduced. Stuffing box packing contact with the ministries and part of the metal surface to be finished, in order to improve the surface finish and reduce packing wear and tear. Flexible graphite packing selected because of their good gas tightness, the friction is small, changes after long-term use of small, wear the burning of a small, maintenance easy, gland bolts re-tightened after the friction does not change, pressure and resistance heat well, is not within the medium erosion, with the stem and the stuffing does not occur within the contact with the metal pitting or corrosion. In this way, the effective protection of the valve stem seal stuffing to ensure the reliability of sealing packing and long-term.
ball valve Trunnion Mounted Ball Valve Floating Ball Valve Top Entry Ball Valve Three way ball valve V Type Ball Valve
We can offer more Knife Gate Valve Information.If you need us according your spcification to produce the Knife Gate Valve .
Need, please e-mail to valve401@gmail.com
Factors affecting valve operation and the countermeasures
1, Introduction
In the higher degree of automation of chemical control system, regulating valve as the implementation of automatic adjustment system, the terminal device to receive control signals to achieve the regulation of chemical processes. It is directly related to the sensitivity of the action-conditioning systems quality. According to the site of about 70% of the actual statistics of the failures come from regulating valve. Therefore, routine maintenance review and analyze the impact the safe operation of control valve factors and countermeasures.
2, card blocking
Valve recurring problem is that card blocked, often appear in the new transport system and the overhaul of investment put into operation in the initial stage, due to pipe welding slag, rust, etc. at the cutting mouth, oriented so that part of blockage caused by poor circulation media, or regulating valve repair in the tight packing, resulting in increased friction, leading to large-signal small-signal non-action motion overshoot phenomenon.
Troubleshooting: You can quickly open, off-line or adjust the valve, vice, so that dirt from the Vice-line or adjust the valve was washed medium run. Another way to stem tube clamp tight, plus the signal pressure in the case, the positive and negative force rotating stem, so that spool flash card office. If it is not an increase of gas pressure to increase the drive power source has repeatedly moved up and down several times, you can solve the problem. Should the motion not, it would take the disintegration of treatment.
3, leakage
3.1 valve leakage, valve stem length of the discomfort. Air to open valve, stem long stem up (or down) the distance is not enough, resulting in gaps between the valve core and valve seat can not be full access, leading to lax customs and internal leakage. Similarly, gas off valve stem is too short, resulting in gaps between the valve core and valve seat can not be full access, leading to lax customs and internal leakage.
Solution: should be shortened (or extended) regulating valve stem so that the length of the right valve so that it no longer internal leakage.
3.2 packing leakage. Packing into stuffing after the axial pressure imposed by the gland. Because the plastic filler to produce a radial force, and close contact with the valve stem, but this contact is not very uniform. Some parts of the loose contact with some parts of the tight contact with, or even no contact at some parts. Regulating valve in the use process, the stem with the filling between the relative movement, this movement is called axial movement. The use of the process, with the high-temperature, high pressure and permeability of fluid medium strong, regulating valve packing leak letter is part of larger phenomena. Is mainly due to leakage caused by filler interface leakage, will appear for the textile and packing leakage (pressure medium along the filler-gap between the small outward leak). The interface between the stem and the packing leakage is due to the gradual attenuation of the contact pressure filler, filler causes such as their own aging, when the pressure medium will be along the contact between the filler and the valve stem outward leakage gap.
Countermeasures: In order to facilitate the filler loading, in the stuffing to the top chamfer, in the stuffing box placed at the bottom of the smaller gap erosion-resistant metal protection ring (with the contact surface can not fill slope) in order to prevent the fill material was medium pressure introduced. Stuffing box packing contact with the ministries and part of the metal surface to be finished, in order to improve the surface finish and reduce packing wear and tear. Flexible graphite packing selected because of their good gas tightness, the friction is small, changes after long-term use of small, wear the burning of a small, maintenance easy, gland bolts re-tightened after the friction does not change, pressure and resistance heat well, is not within the medium erosion, with the stem and the stuffing does not occur within the contact with the metal pitting or corrosion. In this way, the effective protection of the valve stem seal stuffing to ensure the reliability of sealing packing and long-term.
3.3 spool, valve leakage distortion. Core, valve leakage was mainly caused by the production process control valve in the casting or forging defects can lead to corrosion strengthened. The corrosive medium through the fluid medium can also result in erosion control valve leakage. Erosion or corrosion mainly exists in the form of cavitation. When the corrosive medium through the valve, it will give rise to spool, valve seat materials, erosion and impact so that valve core, valve seat into an oval or other shape, as time goes on, leading to valve core, valve seat is not matching, there is clearance, Guan lax leak.
Solution: The key to a good valve core, valve seat material selection customs, quality. Select corrosion-resistant materials, Ma points, trachoma and other defective products and resolutely removed. If the valve core, valve seat deformation is not serious, can grind through the fine sandpaper to remove traces, improve sealing finish to improve sealing performance. If serious damage, it should be re-replaced with new valves.
4, oscillation
Control valve spring stiffness of inadequate control valve output signal instability could easily cause a drastic change in valve oscillation. Also that the election of the frequency of the system valve or pipe the same frequency, base severe vibration, so that control valve resulting vibrations. Selection of improper valve working in a small opening there is a violent flow resistance, velocity, pressure changes, when more than valve stiffness, stability deteriorated, severe oscillation.
Solutions: As the oscillation are many reasons, so the concrete analysis of specific problems. A slight vibration vibration, can increase the stiffness to eliminate. Chooses to use the large stiffness of spring, use piston implementation structures. Pipeline, the base support by increasing the elimination of severe shock vibration interference; selected valve the same as the frequency and system frequency, then switch to a different structure of the valve; work in the small openings caused by the oscillation, it is improper selection of flow capacity of C values of selected large, Selection of capacity C must be re-circulation of the value of the smaller or using sub-process control valves, or Picture-regulating valve in order to overcome the work of a small opening.
5, valve positioner faults
5.1 Common locator using mechanical force balance principle, namely nozzle baffle technology, mainly in the following fault types:
1) the use of mechanical force balance principle of work and its moving parts are more susceptible to temperature, vibration, resulting in control valve fluctuations;
2) The nozzle shield technology, due to the nozzle hole is very small, prone to dust or clean gas source block is the locator does not work;
3) Use of force balance principle, elasticity of the spring occurs in adverse changes in the scene, resulting in non-linear lead to the control valve decline in the quality.
5.2 Smart Positioning is controlled by the microprocessor (cpu), A / D, D / A converter and other components, whose working principle and common Locator different. For a given value and actual value comparison of purely electric signal, is no longer a force balance. Therefore, to overcome the conventional force balance locator shortcomings. However, for emergency parking lot timely, such as emergency shut-off valves, emergency venting valve. These valves require stationary at a certain location, only an emergency occurs, it requires good movement. Prolonged stay in a location easy for the electric converter small-signal does not cause uncontrolled movements of hazardous situations. In addition, the valve position sensor for the potentiometer as a result of on-site, easy to change in resistance value caused by the small-signal non-action, large-signal full-hazards. Therefore, in order to ensure the reliability and intelligent positioning device availability, they must be frequently tested.
6, Conclusion
By regulating valve failure cause analysis and take appropriate treatment, improved methods will greatly enhance the utilization of regulating valve to reduce instrument failure rate, the process technology to improve production efficiency and cost-effective and energy consumption all have an important role in reducing can effectively improve the quality of conditioning systems, thereby ensuring long-cycle production plants running.
ball valve Trunnion Mounted Ball Valve Floating Ball Valve Top Entry Ball Valve ball valve V Type Ball Valve
We can offer more Knife Gate Valve Information.If you need us according your spcification to produce the Knife Gate Valve .
Need, please e-mail to valve401@gmail.com
In the higher degree of automation of chemical control system, regulating valve as the implementation of automatic adjustment system, the terminal device to receive control signals to achieve the regulation of chemical processes. It is directly related to the sensitivity of the action-conditioning systems quality. According to the site of about 70% of the actual statistics of the failures come from regulating valve. Therefore, routine maintenance review and analyze the impact the safe operation of control valve factors and countermeasures.
2, card blocking
Valve recurring problem is that card blocked, often appear in the new transport system and the overhaul of investment put into operation in the initial stage, due to pipe welding slag, rust, etc. at the cutting mouth, oriented so that part of blockage caused by poor circulation media, or regulating valve repair in the tight packing, resulting in increased friction, leading to large-signal small-signal non-action motion overshoot phenomenon.
Troubleshooting: You can quickly open, off-line or adjust the valve, vice, so that dirt from the Vice-line or adjust the valve was washed medium run. Another way to stem tube clamp tight, plus the signal pressure in the case, the positive and negative force rotating stem, so that spool flash card office. If it is not an increase of gas pressure to increase the drive power source has repeatedly moved up and down several times, you can solve the problem. Should the motion not, it would take the disintegration of treatment.
3, leakage
3.1 valve leakage, valve stem length of the discomfort. Air to open valve, stem long stem up (or down) the distance is not enough, resulting in gaps between the valve core and valve seat can not be full access, leading to lax customs and internal leakage. Similarly, gas off valve stem is too short, resulting in gaps between the valve core and valve seat can not be full access, leading to lax customs and internal leakage.
Solution: should be shortened (or extended) regulating valve stem so that the length of the right valve so that it no longer internal leakage.
3.2 packing leakage. Packing into stuffing after the axial pressure imposed by the gland. Because the plastic filler to produce a radial force, and close contact with the valve stem, but this contact is not very uniform. Some parts of the loose contact with some parts of the tight contact with, or even no contact at some parts. Regulating valve in the use process, the stem with the filling between the relative movement, this movement is called axial movement. The use of the process, with the high-temperature, high pressure and permeability of fluid medium strong, regulating valve packing leak letter is part of larger phenomena. Is mainly due to leakage caused by filler interface leakage, will appear for the textile and packing leakage (pressure medium along the filler-gap between the small outward leak). The interface between the stem and the packing leakage is due to the gradual attenuation of the contact pressure filler, filler causes such as their own aging, when the pressure medium will be along the contact between the filler and the valve stem outward leakage gap.
Countermeasures: In order to facilitate the filler loading, in the stuffing to the top chamfer, in the stuffing box placed at the bottom of the smaller gap erosion-resistant metal protection ring (with the contact surface can not fill slope) in order to prevent the fill material was medium pressure introduced. Stuffing box packing contact with the ministries and part of the metal surface to be finished, in order to improve the surface finish and reduce packing wear and tear. Flexible graphite packing selected because of their good gas tightness, the friction is small, changes after long-term use of small, wear the burning of a small, maintenance easy, gland bolts re-tightened after the friction does not change, pressure and resistance heat well, is not within the medium erosion, with the stem and the stuffing does not occur within the contact with the metal pitting or corrosion. In this way, the effective protection of the valve stem seal stuffing to ensure the reliability of sealing packing and long-term.
3.3 spool, valve leakage distortion. Core, valve leakage was mainly caused by the production process control valve in the casting or forging defects can lead to corrosion strengthened. The corrosive medium through the fluid medium can also result in erosion control valve leakage. Erosion or corrosion mainly exists in the form of cavitation. When the corrosive medium through the valve, it will give rise to spool, valve seat materials, erosion and impact so that valve core, valve seat into an oval or other shape, as time goes on, leading to valve core, valve seat is not matching, there is clearance, Guan lax leak.
Solution: The key to a good valve core, valve seat material selection customs, quality. Select corrosion-resistant materials, Ma points, trachoma and other defective products and resolutely removed. If the valve core, valve seat deformation is not serious, can grind through the fine sandpaper to remove traces, improve sealing finish to improve sealing performance. If serious damage, it should be re-replaced with new valves.
4, oscillation
Control valve spring stiffness of inadequate control valve output signal instability could easily cause a drastic change in valve oscillation. Also that the election of the frequency of the system valve or pipe the same frequency, base severe vibration, so that control valve resulting vibrations. Selection of improper valve working in a small opening there is a violent flow resistance, velocity, pressure changes, when more than valve stiffness, stability deteriorated, severe oscillation.
Solutions: As the oscillation are many reasons, so the concrete analysis of specific problems. A slight vibration vibration, can increase the stiffness to eliminate. Chooses to use the large stiffness of spring, use piston implementation structures. Pipeline, the base support by increasing the elimination of severe shock vibration interference; selected valve the same as the frequency and system frequency, then switch to a different structure of the valve; work in the small openings caused by the oscillation, it is improper selection of flow capacity of C values of selected large, Selection of capacity C must be re-circulation of the value of the smaller or using sub-process control valves, or Picture-regulating valve in order to overcome the work of a small opening.
5, valve positioner faults
5.1 Common locator using mechanical force balance principle, namely nozzle baffle technology, mainly in the following fault types:
1) the use of mechanical force balance principle of work and its moving parts are more susceptible to temperature, vibration, resulting in control valve fluctuations;
2) The nozzle shield technology, due to the nozzle hole is very small, prone to dust or clean gas source block is the locator does not work;
3) Use of force balance principle, elasticity of the spring occurs in adverse changes in the scene, resulting in non-linear lead to the control valve decline in the quality.
5.2 Smart Positioning is controlled by the microprocessor (cpu), A / D, D / A converter and other components, whose working principle and common Locator different. For a given value and actual value comparison of purely electric signal, is no longer a force balance. Therefore, to overcome the conventional force balance locator shortcomings. However, for emergency parking lot timely, such as emergency shut-off valves, emergency venting valve. These valves require stationary at a certain location, only an emergency occurs, it requires good movement. Prolonged stay in a location easy for the electric converter small-signal does not cause uncontrolled movements of hazardous situations. In addition, the valve position sensor for the potentiometer as a result of on-site, easy to change in resistance value caused by the small-signal non-action, large-signal full-hazards. Therefore, in order to ensure the reliability and intelligent positioning device availability, they must be frequently tested.
6, Conclusion
By regulating valve failure cause analysis and take appropriate treatment, improved methods will greatly enhance the utilization of regulating valve to reduce instrument failure rate, the process technology to improve production efficiency and cost-effective and energy consumption all have an important role in reducing can effectively improve the quality of conditioning systems, thereby ensuring long-cycle production plants running.
ball valve Trunnion Mounted Ball Valve Floating Ball Valve Top Entry Ball Valve ball valve V Type Ball Valve
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The circumstances in which use bellows seal globe valve
Bellows Seal Globe Valve, its key components - metal bellows, bottom and stem components of automatic roll-welding, automatic roll-top with the connecting plate welding, in the fluid medium and the formation of a metal barrier between the atmosphere, to ensure that valves pole zero leakage. Valve flap and valve sealing surface through precision grinding, assembled over 100% pressure test, all to achieve zero leakage. As an auxiliary in sealed bellows above the stuffing is still preserved, but also increased the reliability and security. High-pressure valves are multi-layer structure of corrugated metal pipe by hydroforming can ensure that the maximum pressure of 10,000 times the whole trip on / off life expectancy.
The use of advantages:
1, a double seal design (corrugated pipe + packing) if the bellows fails, valve stem packing will prevent leaks, and sealed in accordance with international standards.
2, safety and environmental protection, there is no fluid loss, reduce energy losses, increase plant safety equipment.
3, long service life, reduced maintenance frequency, lower operating costs.
4, strong and durable bellows seal design to ensure zero leakage valve stem to provide maintenance-free conditions.
Use range:
Applicable to heat-conducting oil, toxic, flammable, strong permeability, pollute the environment with radioactive fluid medium tubes on the road to cut off the valve can also be used to adjust the factory is to create high-quality products without leakage. The valves used in all casting precision casting.
ball valve Trunnion Mounted Ball Valve Floating Ball Valve Top Entry Ball Valve ball valve V Type Ball Valve
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The use of advantages:
1, a double seal design (corrugated pipe + packing) if the bellows fails, valve stem packing will prevent leaks, and sealed in accordance with international standards.
2, safety and environmental protection, there is no fluid loss, reduce energy losses, increase plant safety equipment.
3, long service life, reduced maintenance frequency, lower operating costs.
4, strong and durable bellows seal design to ensure zero leakage valve stem to provide maintenance-free conditions.
Use range:
Applicable to heat-conducting oil, toxic, flammable, strong permeability, pollute the environment with radioactive fluid medium tubes on the road to cut off the valve can also be used to adjust the factory is to create high-quality products without leakage. The valves used in all casting precision casting.
ball valve Trunnion Mounted Ball Valve Floating Ball Valve Top Entry Ball Valve ball valve V Type Ball Valve
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Sunday, September 26, 2010
Backflow valve to prevent media
Valve to prevent backflow of the media is allowed only in one direction to the flow of media, but also to prevent the flow direction. This valve is usually the work automatically, in a direction of flow of fluid under pressure, open the valve; fluid flowing in the opposite direction, fluid pressure and the valve from the valve since the role of coincidence in the valve seat, thereby cutting off the flow. Non-return valve which belongs to this type of valve, which includes Swing Check Valve Check Valve and the take-off and landing. Swing Check Valve bodies are ordinary hinge, there is a door the same as the free flap valve against the valve seat sloping surface.
In order to ensure that every valve seat surface to reach the appropriate position in the valve hinge design in order to have a valve Swing have sufficient space and the real valve, all-round contact with the valve seat. Valve could be made of metal can also be embedded in the metal on leather, rubber, or synthetic coverage, depending on the use of performance requirements. Swing Check Valve fully opened in the circumstances, almost unimpeded fluid pressure, so the pressure drop through the valve is relatively small. Take-off and landing flap-type check valve is located at the valve seat sealing surface of the body. In addition to this valve valve is free to take-off and landing, the other part as the same cut-off valve, fluid pressure valve lift from the valve seat sealing surface, leading to medium return valve to the valve seat down, and cut off the flow. Under the conditions of use, valve can be all-metal structure can also be rack mounted in the valve rubber mat or rubber ring form. The same as the cut-off valve, fluid movements through the channel-type check valve is narrow, and therefore through the movements of the pressure drop Check Valve Swing Check Valve than larger, and Swing Check Valve flow restrictions rarely. valve ball valve gate valve check valve globe valve butterfly valve
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In order to ensure that every valve seat surface to reach the appropriate position in the valve hinge design in order to have a valve Swing have sufficient space and the real valve, all-round contact with the valve seat. Valve could be made of metal can also be embedded in the metal on leather, rubber, or synthetic coverage, depending on the use of performance requirements. Swing Check Valve fully opened in the circumstances, almost unimpeded fluid pressure, so the pressure drop through the valve is relatively small. Take-off and landing flap-type check valve is located at the valve seat sealing surface of the body. In addition to this valve valve is free to take-off and landing, the other part as the same cut-off valve, fluid pressure valve lift from the valve seat sealing surface, leading to medium return valve to the valve seat down, and cut off the flow. Under the conditions of use, valve can be all-metal structure can also be rack mounted in the valve rubber mat or rubber ring form. The same as the cut-off valve, fluid movements through the channel-type check valve is narrow, and therefore through the movements of the pressure drop Check Valve Swing Check Valve than larger, and Swing Check Valve flow restrictions rarely. valve ball valve gate valve check valve globe valve butterfly valve
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Sunday, September 19, 2010
The development of pipeline valves
I. Preface
In 1914, the first 9 kilometers long oil pipeline built in the central United States, from the opening prelude to industrial development pipeline. By pipeline for the transmission of liquid or gas, the cost of rail transport is 1 / 3, the sea transport of 2 / 3, so the last one hundred years to obtain a rapid development. Described as long-distance pipelines of long-distance pipeline, the use of long-distance pipeline valve called a pipeline valve, a ball valve, gate valve, check valve, plug valves, is a pipeline transportation to meet the special requirements of have dedicated special function valves. Ball said that the pipeline of the ball valve. Pipeline ball valve specification is the technical standards issued by the American Petroleum Institute API specification 6D "oil and natural gas industries - Pipeline transportation - pipeline valves", the latest version in January 2000 edition of the enactment of section 22, and in 1999 issued international standards ISO14313 - 1999.
In fact the rapid development of pipeline industry is the fifties of the twentieth century, and under the "Pipeline" magazine in 2000 statistics, the world's pipelines have been completed and 2.6 million kilometers, of which 800,000 kilometers pipeline, 1.4 million kilometers pipelines, other petrochemical products pipelines 400,000 kilometers. Oil pipelines is an energy supply line, is a lifeline, has been around the world, and still 30,000 kilometers per year annually. The maximum pipeline pressure level valve PN42.0Mpa (Class2500), Valve's largest 60-inch diameter (DN1500).
The world famous long-distance pipelines such as the United States east coast of Alaska to the Atlantic Ocean crude oil pipeline in Long Island, across the Arctic permafrost and the United States, the marshes of the Great Lakes; the Russian Trans-Siberian oil pipeline; the Mediterranean from Algeria to Spain via Morocco the gas line, a total length of 2,000 km, across the desert, the Atlas Mountains and the Strait of Gibraltar; in Southeast Asia from the Philippines via Malaysia, Java, Sumatra, Thailand, a total length of 6276 kilometers to the gas line, in which 1094 kilometers submarine gas line, and so on.
The structure of ball valve can be traced back to 1904, the structure has been applied for the patent, but has not been commercialized, it is also the 20th century, the development of the 50's thing, this is the United States in 1943 as a result of DuPont invented Teflon plastic This material has a certain degree of flexibility, self-lubricating, and excellent corrosion resistance, very suitable for the sealing materials as valves. As well as the cars ball machine, ball machine progress. As a result of this is the path valve, low flow resistance, is suitable for use as a long-distance pipeline valves, pipeline ball valve so the pipeline has been gradually replacing the valve, plug valves, is a kind of the last 50 years one of the fastest growing valve new varieties. valve ball valve gate valve check valve globe valve butterfly valve
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Need, please e-mail to valve401@gmail.com
In 1914, the first 9 kilometers long oil pipeline built in the central United States, from the opening prelude to industrial development pipeline. By pipeline for the transmission of liquid or gas, the cost of rail transport is 1 / 3, the sea transport of 2 / 3, so the last one hundred years to obtain a rapid development. Described as long-distance pipelines of long-distance pipeline, the use of long-distance pipeline valve called a pipeline valve, a ball valve, gate valve, check valve, plug valves, is a pipeline transportation to meet the special requirements of have dedicated special function valves. Ball said that the pipeline of the ball valve. Pipeline ball valve specification is the technical standards issued by the American Petroleum Institute API specification 6D "oil and natural gas industries - Pipeline transportation - pipeline valves", the latest version in January 2000 edition of the enactment of section 22, and in 1999 issued international standards ISO14313 - 1999.
In fact the rapid development of pipeline industry is the fifties of the twentieth century, and under the "Pipeline" magazine in 2000 statistics, the world's pipelines have been completed and 2.6 million kilometers, of which 800,000 kilometers pipeline, 1.4 million kilometers pipelines, other petrochemical products pipelines 400,000 kilometers. Oil pipelines is an energy supply line, is a lifeline, has been around the world, and still 30,000 kilometers per year annually. The maximum pipeline pressure level valve PN42.0Mpa (Class2500), Valve's largest 60-inch diameter (DN1500).
The world famous long-distance pipelines such as the United States east coast of Alaska to the Atlantic Ocean crude oil pipeline in Long Island, across the Arctic permafrost and the United States, the marshes of the Great Lakes; the Russian Trans-Siberian oil pipeline; the Mediterranean from Algeria to Spain via Morocco the gas line, a total length of 2,000 km, across the desert, the Atlas Mountains and the Strait of Gibraltar; in Southeast Asia from the Philippines via Malaysia, Java, Sumatra, Thailand, a total length of 6276 kilometers to the gas line, in which 1094 kilometers submarine gas line, and so on.
The structure of ball valve can be traced back to 1904, the structure has been applied for the patent, but has not been commercialized, it is also the 20th century, the development of the 50's thing, this is the United States in 1943 as a result of DuPont invented Teflon plastic This material has a certain degree of flexibility, self-lubricating, and excellent corrosion resistance, very suitable for the sealing materials as valves. As well as the cars ball machine, ball machine progress. As a result of this is the path valve, low flow resistance, is suitable for use as a long-distance pipeline valves, pipeline ball valve so the pipeline has been gradually replacing the valve, plug valves, is a kind of the last 50 years one of the fastest growing valve new varieties. valve ball valve gate valve check valve globe valve butterfly valve
We can offer more Knife Gate Valve Information.If you need us according your spcification to produce the Knife Gate Valve .
Need, please e-mail to valve401@gmail.com
Saturday, September 18, 2010
Fault Analysis boiler valve safety valve (b)
3 is the main safety valve and safety valve mismatch impulse, impulse steam flow valve is too small. Impulse valve nominal diameter is too small, resulting in the piston chamber into the main steam safety valve insufficient to promote the piston downward movement of the force f1 is not enough, that is, f1 <f2 + f3 + fm causing the main valve spool not move. This phenomenon occurred mostly in the main safety valve safety valve-type impulse there is a replacement, due to a result of ill-considered.
For example, No. 5 furnace overhaul in 2002, it will be two heavy hammer-type impulse valve replaced with two valve plant in Harbin, A49H-P54100VDg20 pulsed valve, this valve type generally associated with spring-A42H-P54100VDg125 matched the main safety , it would be produced with the Soviet Union Dg150 × 90 × 250-type old-fashioned main safety valve supporting the use of such a primary safety valve with spring-A29H-P54100VDg125 the main safety valve of this type than the nominal diameter is not only larger but also less air tightness in the No. 5 furnace capacity safety valve set ram is completed, to run ram tests caused by the main safety valve refused to move.
Later we will impulse valve disintegrated, its orientation with the part of the sleeve and spool gap expanded to increase its flow area, once again ran a successful pilot mound. So the impulse valve and the main valve mismatch, the smaller nominal diameter can also cause the main valve to resist moving.
2.4, impulse valve safety valve back seat emperor back seat for too long delay
The major causes of this failure occurs the following two aspects:
On the one hand, the main valve piston chamber the size of the leakage of steam, although the impulse valve back seat, but the existence of the pipeline and the piston chamber of the steam pressure is still high, push the piston downward force is still large, Therefore, the main valve back seat cause retardation, this failure will occur in the A42Y-P5413.7VDg100-type safety valve, because this type of relief valve piston chamber gas seal was good. Ways to eliminate this failure, mainly through large throttle opening and increasing the opening degree of throttle aperture to be resolved, the opening degree of throttle opening and the throttle aperture large increase in both pulse tube remaining in the rapid discharge of steam out , thereby reducing the pressure inside the piston to effect the downward movement in the piston thrust rapidly decreases spool together in the steam box steam media set up its own thrust and the main safety valve under the action of spring pull up quickly to Block.
The other reason is that the main valve of the moving parts and fixed friction between the components is too large can also cause the main valve back seat slow way to solve this problem is to the main safety valve moving parts and fixed parts with the clearance Console standard range.
2.5, low pressure safety valve of the back seat
Low-pressure safety valve back seat to the boiler running a great risk to the economy, back seat pressure is too low will result in a lot of media time-out emissions, resulting in unnecessary energy loss. Such failures have occurred within the 200MW unit used by the A49H-type spring pulse valve, the analysis of the reasons is mainly composed of the following factors:
First, spring safety valve on the pulse of the excretion of large amount of steam, this form of the impulse valve is turned on, the media continue to discharge to promote the main safety valve action.
On the one hand is the impulse valve before the pressure due to the main valve of the media continue to increase in emissions is not enough, so the steam inside the pulse tube gas gathering together along the drum or tank to continue to maintain the flow of impulse impulse valve safety valve action.
On the other hand due to this type of impulse flow of media through the valve spool and the guide sets the gap between the flow of the main valve piston chamber, the medium out of impulse valve sealing surface around the formation of kinetic energy of the pressure in their area, raise the spool, so the impulse to continue to discharge safety valve, steam emissions, the greater the kinetic energy of the pressure zone valve core part of the pressure the greater the role of the upward thrust on the spool the greater the less impulse valve easy to back seat, this time way to eliminate this failure is to throttle off small, so that the media out of impulse decrease in the flow valve to reduce pressure on kinetic pressure of the region, so that impulse valve back seat.
Back seat low pressure caused by the second factor is: spool and the guide sleeve with clearance inappropriate, with the gap is too small, in the impulse valve seat Kai, after an instant savings in this formed part of the kinetic energy of a high pressure zone will be Spool inflate the seat back to the time delay, when the container dropped to low, the kinetic energy pressure area pressure decreases, impulse valve back seat.
To eliminate this failure is to carefully check the spool and the guide cover the various parts of sizes, with the gap over an hour, reducing the valve flap flap valve sealing surface of straight-type gas cap diameter, or increased resistance valve flap and the radial clearance between the guide sleeve , to increase the parts of the flow area, so that the steam flows through it without too much throttle, leaving partial pressure increases the kinetic energy of the formation of a high pressure zone.
Low-pressure caused by back seat, another reason is that the movement part of friction force, some parts of a jam, the solution is to carefully examine all moving parts, strictly in accordance with maintenance standards for maintenance of various components for each of the components adjusted to meet the gap standards, to remove the possibility of jam.
2.6, the frequency of safety valve jump
Frequency-hop refers to the safety valve back seat and after a slightly elevated pressure, turn valve to open, repeated on several occasions, this phenomenon is known as a safety valve, "frequency jump." Mechanical properties required safety valve safety valve movement in the whole process of opening up to the required height, does not allow for card blocking, tremor and frequency jump phenomenon. The frequency jump phenomenon on the valve seal is extremely detrimental to the sealing surface can easily result in the leakage. Analyze the reasons mainly related to the pressure relief valve back to seat up to high-related back to block the pressure is high, the container medium excess emissions less valve seat has been returned, and when the operating personnel to adjust properly, the pressure inside the container will soon be l up, so the valve caused by movements like this can be accessed via the opening degree of throttle opening its way to be removed. Open the throttle, after leading off the main valve piston to reduce the indoor steam source to promote a smaller force the piston downward movement, the main safety valve action less likely, thus avoiding the main safety valve to start a row.
2.7, a safety valve flutter
Safety valve in the discharge occurred during the jitter phenomenon, called a safety valve flutter, flutter easily result in the occurrence of the phenomenon of metal fatigue, so that the mechanical valve performance degradation, resulting in serious risks of equipment occurred chatter because of the following aspects:
On the one hand is the improper use of the valve, the discharge capacity of selected valve too (as opposed to be in terms of emissions), the elimination method is to make use of the valve should be rated for emissions equipment as close as possible the necessary emissions.
On the other hand is due to imports of the pipe diameter is too small, less than the valve diameter of imports, or imports of tube resistance is too large to eliminate valve installation method is to make imports of tube diameter of not less than the valve diameter of imports or to reduce the imports of pipe resistance. Discharge piping resistance is too large, resulting in excessive emissions from the north when the pressure is caused by a factor of flutter valve, you can pipe the resistance by reducing the emissions to be addressed.
3, Conclusion
The boiler safety valve on the causes of common faults were analyzed and put forward concrete solutions, although the boiler safety valve by the primary, secondary valve supporting composition, and mechanical and thermal control of dual protection, and some fault less liable to occur, but only to fully grasp the safety valve to eliminate common failure causes and methods of dealing with them in the event of a failure can be handy in ensuring the safe operation of equipment, has an important significance. ball valve Trunnion Mounted Ball Valve Floating Ball Valve Top Entry Ball Valve Three way ball valve V Type Ball Valve
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Need, please e-mail to valve401@gmail.com
For example, No. 5 furnace overhaul in 2002, it will be two heavy hammer-type impulse valve replaced with two valve plant in Harbin, A49H-P54100VDg20 pulsed valve, this valve type generally associated with spring-A42H-P54100VDg125 matched the main safety , it would be produced with the Soviet Union Dg150 × 90 × 250-type old-fashioned main safety valve supporting the use of such a primary safety valve with spring-A29H-P54100VDg125 the main safety valve of this type than the nominal diameter is not only larger but also less air tightness in the No. 5 furnace capacity safety valve set ram is completed, to run ram tests caused by the main safety valve refused to move.
Later we will impulse valve disintegrated, its orientation with the part of the sleeve and spool gap expanded to increase its flow area, once again ran a successful pilot mound. So the impulse valve and the main valve mismatch, the smaller nominal diameter can also cause the main valve to resist moving.
2.4, impulse valve safety valve back seat emperor back seat for too long delay
The major causes of this failure occurs the following two aspects:
On the one hand, the main valve piston chamber the size of the leakage of steam, although the impulse valve back seat, but the existence of the pipeline and the piston chamber of the steam pressure is still high, push the piston downward force is still large, Therefore, the main valve back seat cause retardation, this failure will occur in the A42Y-P5413.7VDg100-type safety valve, because this type of relief valve piston chamber gas seal was good. Ways to eliminate this failure, mainly through large throttle opening and increasing the opening degree of throttle aperture to be resolved, the opening degree of throttle opening and the throttle aperture large increase in both pulse tube remaining in the rapid discharge of steam out , thereby reducing the pressure inside the piston to effect the downward movement in the piston thrust rapidly decreases spool together in the steam box steam media set up its own thrust and the main safety valve under the action of spring pull up quickly to Block.
The other reason is that the main valve of the moving parts and fixed friction between the components is too large can also cause the main valve back seat slow way to solve this problem is to the main safety valve moving parts and fixed parts with the clearance Console standard range.
2.5, low pressure safety valve of the back seat
Low-pressure safety valve back seat to the boiler running a great risk to the economy, back seat pressure is too low will result in a lot of media time-out emissions, resulting in unnecessary energy loss. Such failures have occurred within the 200MW unit used by the A49H-type spring pulse valve, the analysis of the reasons is mainly composed of the following factors:
First, spring safety valve on the pulse of the excretion of large amount of steam, this form of the impulse valve is turned on, the media continue to discharge to promote the main safety valve action.
On the one hand is the impulse valve before the pressure due to the main valve of the media continue to increase in emissions is not enough, so the steam inside the pulse tube gas gathering together along the drum or tank to continue to maintain the flow of impulse impulse valve safety valve action.
On the other hand due to this type of impulse flow of media through the valve spool and the guide sets the gap between the flow of the main valve piston chamber, the medium out of impulse valve sealing surface around the formation of kinetic energy of the pressure in their area, raise the spool, so the impulse to continue to discharge safety valve, steam emissions, the greater the kinetic energy of the pressure zone valve core part of the pressure the greater the role of the upward thrust on the spool the greater the less impulse valve easy to back seat, this time way to eliminate this failure is to throttle off small, so that the media out of impulse decrease in the flow valve to reduce pressure on kinetic pressure of the region, so that impulse valve back seat.
Back seat low pressure caused by the second factor is: spool and the guide sleeve with clearance inappropriate, with the gap is too small, in the impulse valve seat Kai, after an instant savings in this formed part of the kinetic energy of a high pressure zone will be Spool inflate the seat back to the time delay, when the container dropped to low, the kinetic energy pressure area pressure decreases, impulse valve back seat.
To eliminate this failure is to carefully check the spool and the guide cover the various parts of sizes, with the gap over an hour, reducing the valve flap flap valve sealing surface of straight-type gas cap diameter, or increased resistance valve flap and the radial clearance between the guide sleeve , to increase the parts of the flow area, so that the steam flows through it without too much throttle, leaving partial pressure increases the kinetic energy of the formation of a high pressure zone.
Low-pressure caused by back seat, another reason is that the movement part of friction force, some parts of a jam, the solution is to carefully examine all moving parts, strictly in accordance with maintenance standards for maintenance of various components for each of the components adjusted to meet the gap standards, to remove the possibility of jam.
2.6, the frequency of safety valve jump
Frequency-hop refers to the safety valve back seat and after a slightly elevated pressure, turn valve to open, repeated on several occasions, this phenomenon is known as a safety valve, "frequency jump." Mechanical properties required safety valve safety valve movement in the whole process of opening up to the required height, does not allow for card blocking, tremor and frequency jump phenomenon. The frequency jump phenomenon on the valve seal is extremely detrimental to the sealing surface can easily result in the leakage. Analyze the reasons mainly related to the pressure relief valve back to seat up to high-related back to block the pressure is high, the container medium excess emissions less valve seat has been returned, and when the operating personnel to adjust properly, the pressure inside the container will soon be l up, so the valve caused by movements like this can be accessed via the opening degree of throttle opening its way to be removed. Open the throttle, after leading off the main valve piston to reduce the indoor steam source to promote a smaller force the piston downward movement, the main safety valve action less likely, thus avoiding the main safety valve to start a row.
2.7, a safety valve flutter
Safety valve in the discharge occurred during the jitter phenomenon, called a safety valve flutter, flutter easily result in the occurrence of the phenomenon of metal fatigue, so that the mechanical valve performance degradation, resulting in serious risks of equipment occurred chatter because of the following aspects:
On the one hand is the improper use of the valve, the discharge capacity of selected valve too (as opposed to be in terms of emissions), the elimination method is to make use of the valve should be rated for emissions equipment as close as possible the necessary emissions.
On the other hand is due to imports of the pipe diameter is too small, less than the valve diameter of imports, or imports of tube resistance is too large to eliminate valve installation method is to make imports of tube diameter of not less than the valve diameter of imports or to reduce the imports of pipe resistance. Discharge piping resistance is too large, resulting in excessive emissions from the north when the pressure is caused by a factor of flutter valve, you can pipe the resistance by reducing the emissions to be addressed.
3, Conclusion
The boiler safety valve on the causes of common faults were analyzed and put forward concrete solutions, although the boiler safety valve by the primary, secondary valve supporting composition, and mechanical and thermal control of dual protection, and some fault less liable to occur, but only to fully grasp the safety valve to eliminate common failure causes and methods of dealing with them in the event of a failure can be handy in ensuring the safe operation of equipment, has an important significance. ball valve Trunnion Mounted Ball Valve Floating Ball Valve Top Entry Ball Valve Three way ball valve V Type Ball Valve
We can offer more Knife Gate Valve Information.If you need us according your spcification to produce the Knife Gate Valve .
Need, please e-mail to valve401@gmail.com
Parallel Disc Gate Valve Features
Parallel Disc Gate Valve Features:
(1), Yoke frame tube - aluminum-bronze yoke bushing frame configuration needle thrust bearings, minimizing operating torque.
(2) Stem - thread length until the bracket; pin and spot welding; have stability.
(3) Pressure Seal - simple in structure, configuration sub-buckles, and silver-plated low-carbon steel washers, helping to achieve the best demolition and sealing valve cap.
(4) The valve seat ring - welded seat ring is perpendicular to flow path, easy to maintain.
(5) implementing agencies - these valves can be configured to electric, hydraulic or pneumatic actuator. DN300 following configuration standards for hand-hands-round, DN350 and above configuration helical gear operating mechanism.
(6) The yoke frame - fully assembled yoke frame through the seismic testing, ease of maintenance and installation of implementing agencies.
(7) gland - two-piece, self-regulating gland, to avoid pop-up.
(8) On the whole back seat - Hard, the longest service life.
(9) valve flap - a spring-loaded valve flap to the self-implementing agencies to reduce the torque requirements.
(10) Overall Stop - the whole cast bracket stop device, positioning valve flap bracket assembly, making the valve seat is more stable and reliable.
ball valve Trunnion Mounted Ball Valve Floating Ball Valve Top Entry Ball Valve ball valve V Type Ball Valve
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Wednesday, September 15, 2010
Global valve market
Valve as a result of the global market more competitive, many of the world's leading manufacturers of valves closed in North America, Europe and Japan, the factory moved to China, India, South Korea and China and the EU in order to reduce manufacturing costs valve and increase sales. With China's development and utilization of oil and natural gas to increase the strength of China valve market growth, which makes the majority of valve manufacturers set up factories in China even more important. Thus, the valve appeared of foreign companies set up factories in China's boom, and some enterprises in China and even a number of factories, so as to shorten the transport distance and delivery time.
In 2004, the United States Association valve valve market share of the United States reached 3.18 billion U.S. dollars; the other, according to data on China General Machinery Association, China's valve market exceeded 20 billion yuan by the year 2010, China's domestic demand valve will reach 34.5 billion yuan. The global market sales of all types of valves in about 40 billion U.S. dollars. China Statistical valve more than 2,000 manufacturers, together with other developed and developing countries more than 1,400 valve manufacturers, occupy 80% of global market share; more than 10 other companies hold a joint valves 20 % market share.
Many different types of valves, uses also a wide range of oil and natural gas industry has been the largest valve buyers market. Figure 1 gives the valve in various fields of usage situations. From Figure 2, we can see, oil (including oil refining), the largest amount of natural gas, accounting for 37.4% of the total volume; the field of energy consumption to 21.3% in the valve; the third is the chemical industry, 11.5%; Then the field of water treatment and sewage treatment, 11.4%. valve ball valve gate valve check valve globe valve butterfly valve
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Need, please e-mail to valve401@gmail.com
In 2004, the United States Association valve valve market share of the United States reached 3.18 billion U.S. dollars; the other, according to data on China General Machinery Association, China's valve market exceeded 20 billion yuan by the year 2010, China's domestic demand valve will reach 34.5 billion yuan. The global market sales of all types of valves in about 40 billion U.S. dollars. China Statistical valve more than 2,000 manufacturers, together with other developed and developing countries more than 1,400 valve manufacturers, occupy 80% of global market share; more than 10 other companies hold a joint valves 20 % market share.
Many different types of valves, uses also a wide range of oil and natural gas industry has been the largest valve buyers market. Figure 1 gives the valve in various fields of usage situations. From Figure 2, we can see, oil (including oil refining), the largest amount of natural gas, accounting for 37.4% of the total volume; the field of energy consumption to 21.3% in the valve; the third is the chemical industry, 11.5%; Then the field of water treatment and sewage treatment, 11.4%. valve ball valve gate valve check valve globe valve butterfly valve
We can offer more Knife Gate Valve Information.If you need us according your spcification to produce the Knife Gate Valve .
Need, please e-mail to valve401@gmail.com
Monday, September 13, 2010
Three eccentric butterfly valve characteristics and applications
Third, eccentric disc valve since its inception, in order to meet the growing requirements of harsh operating conditions, is also experiencing its own self-improvement and continuous development process. Even the most basic of zero leakage, in theory, the three eccentric disc valves that can be done, but in reality it depends on the careful design, precision manufacturing. Pakistani butterfly doors Co., Ltd. in the draw, summing up the three other brands eccentric disc valves and weaknesses based on the introduction of its own unique three eccentric disc valve Tritec, the following features:
1, API Specification
As we all know, API609 has in fact become an important line of industrial valves used in the international specifications. Tritec is a comprehensive and strictly in accordance with the latest specification API609 version in 1997 the design, manufacture. Is more valuable, Tritec is not limited to the basic design of an API specification, BS5155 ANSI B 16.34, ASME SEC VIII, such as all the major specifications correspond Tritec This ensures that in all areas of the industrial arena.
2, the dual security structure
Tritec in strict accordance with the specifications of API609, in order to prevent a result of fluid pressure, temperature and deformation caused by the butterfly plate, stem position, sealing surface occlusion, in the butterfly under the lateral plate, respectively, with two separate thrust ring, thereby ensuring the valve in any of the normal working conditions;
At the same time, in order to prevent the stem from breaking loss to know the reasons cited, out of the emergency caused by accident, both inside and outside the bottom two places in the valve design of the stem out of their own to prevent the body from side to ensure that the Tritec pressure level can be as high as 2500 lbs class.
3, no dead-zone design
Tritec in the design process, special consideration in the regulation and control applications in the field, make full use of the three eccentric butterfly valve sealing principle, be a butterfly valve plate does not scratch when the valve seat, valve stem torque directly through the butterfly plate transfer to the sealing surface, which means butterfly plate with almost no friction between the valve seat occurred, thus put an end to the open valve is the common ordinary jump phenomenon, the eradication of the valve opening of the scope of the low internal friction and other non - factors can not be caused by the phenomenon of control, that is, the eradication of the dead zone (not a sense of zone), which means that almost Tritec starting from 0 that is, open access to controlled areas, to open up to 90 degrees, the normal control than the general butterfly valve 2 times more than the maximum control over as much as 100:1. This valve Tritec used as a control to create good conditions, especially in large diameter, the high cost of cut-off valve, In addition, the cut-off valve can not achieve zero leakage, in need of emergency shutdown of the working conditions must be in the cut-off valve off the installation of the side valve, and control and Tritec set off in one, and its cost-effectiveness is extremely significant.
4, seat body structure
Three eccentric butterfly valve installed on the seat structure, there are two, mostly for convenience and the board installed in the butterfly, but the body is used Tritec seat construction, will be installed in the body on the valve seat. The advantage is, compared with the butterfly valve plate, thus greatly reducing the valve seat medium chance of direct contact, thus reducing the extent of erosion by the valve seat, extend the life of the valve seat.
5, thin film valve seat structure
Tritec the seat of stainless steel sheets stacked together with the graphite sheet, this structure can effectively prevent the media and the impact of micro-solid that may arise from thermal expansion of the sealing surface bite, even if the injury appears minor, it would not have leaked , which in the double eccentric butterfly valve or other three-eccentric butterfly valve is inconceivable.
6, can change the seal, Deputy
Vice-Tritec is unique sealing, not only can replace the valve seat body, and as a result of plate sealing surface and the Butterfly Garden is an independent board, butterfly plate sealing surface can be replaced, that is when the butterfly plate when the sealing surface damage, no longerand shipped back to factory or large-scale decomposition of the valve, simply change your butterfly plate sealing surface, which will not only greatly reduces maintenance costs, but also greatly reduces the maintenance and overhaul when the intensity and difficulty.
7, balance of fixed structure
Three eccentric butterfly valve from the sealing surface characteristics of shape, Tritec Vice fixed way of sealing a bolt fixed elliptical distribution, not only positioning accuracy, but also balanced so that each bolt has the force to stop due to stress arising from uneven distribution of Vice loose seal leakage.
8, the nature of fire-resistant structure
Many have claimed to have a fire-resistant valve construction, but the vast majority of valves in order to reduce leakage and the use of hard and soft structures the double seat, in fact, this is very dangerous. Because of fire soft seat seal incomplete combustion of the metal to support the valve seat will cause stress, deformation temperature, resulting in failure of fire-resistant function. Therefore, Europe and the United States is gradually excluded from the current name of the fire resistance of these valves. Tritrc because it is a zero-leakage, so do not need to refer to help soft-sealed, which is truly the essence of fire-resistant construction, and agreed there API607, API6FA and fire resistance test BS6755Part2 qualified certificate. This ensures that Tritec can be applied to petroleum, petrochemical and other hazardous area. In conservative Britain, its North Sea oil fields in all the key parts of the valves used in almost all been won Tritec is the best example of that.
9, high-sealed packing structure
Leakage in the valve issue, traditionally tend to focus on the leakage of the valve seat, that is, within the leak, to the neglect of the Department of leakage of filling materials, namely leakage. In fact, in the current environmental problems are growing in importance in contemporary society, the danger is far greater than with the leak leak has become an indisputable fact. Tritec three eccentric butterfly valves are back in transition, and its stem is only 90 ° rotary movement only, this valve, the valve stem moves, such as for the reciprocating motion of spiral multi-turn compared to the degree of wear and tear suffered by the Department of filler is low, relative to a long life, but also as a result of such Tritec in the packing seal to prevent external leakage of the structure, has taken the highest standards of design, which can be carried out in accordance with the specifications EPA21 external leak test, the sealing performance standards to ensure that the following 100ppm. In fact, the existing test results Tritec, in the case of Lloyd monitoring, external leakage values as low as 7ppm. Tritec means of these indicators can be a variety of chemicals in the field of toxic and hazardous pipelines in the medium to show their talents.
Application of three eccentric butterfly valve
To sum up, the three eccentric butterfly valves as the crystallization of the latest technology, a variety of valves Jan length short to avoid all kinds of valves, the majority of users will more and more attention and designers. Co., Ltd. Butterfly Valve Gate Pakistan Tritec, its level of maximum pressure level can reach 2500 pounds, the standard 48-inch diameter can be done, but also for folders, Ear, flange, ring then, butt welding, Jacket, the length of the various structures and so on to the corresponding, more as a result of Tritec great choice of materials, high temperature and various acids, alkalis and other corrosive media are also able to correspond freely. Especially in the large-diameter area, with its constantly zero leakage of the valve and replace the large ball valve, and similarly, the function of its excellent control, in-control valve also being constantly replaced by advantages in turn-off valve, the cut-off valve is bulky. As a fact, so far, Tritec has been used in, including China, oil and gas exploration, offshore platforms, oil refining, petrochemicals, inorganic chemicals, energy generation, such as major industrial sectors such as process control on an important pipeline.
We can offer more Knife Gate Valve Information.If you need us according your spcification to produce the Knife Gate Valve .
Need, please e-mail to valve401@gmail.com
1, API Specification
As we all know, API609 has in fact become an important line of industrial valves used in the international specifications. Tritec is a comprehensive and strictly in accordance with the latest specification API609 version in 1997 the design, manufacture. Is more valuable, Tritec is not limited to the basic design of an API specification, BS5155 ANSI B 16.34, ASME SEC VIII, such as all the major specifications correspond Tritec This ensures that in all areas of the industrial arena.
2, the dual security structure
Tritec in strict accordance with the specifications of API609, in order to prevent a result of fluid pressure, temperature and deformation caused by the butterfly plate, stem position, sealing surface occlusion, in the butterfly under the lateral plate, respectively, with two separate thrust ring, thereby ensuring the valve in any of the normal working conditions;
At the same time, in order to prevent the stem from breaking loss to know the reasons cited, out of the emergency caused by accident, both inside and outside the bottom two places in the valve design of the stem out of their own to prevent the body from side to ensure that the Tritec pressure level can be as high as 2500 lbs class.
3, no dead-zone design
Tritec in the design process, special consideration in the regulation and control applications in the field, make full use of the three eccentric butterfly valve sealing principle, be a butterfly valve plate does not scratch when the valve seat, valve stem torque directly through the butterfly plate transfer to the sealing surface, which means butterfly plate with almost no friction between the valve seat occurred, thus put an end to the open valve is the common ordinary jump phenomenon, the eradication of the valve opening of the scope of the low internal friction and other non - factors can not be caused by the phenomenon of control, that is, the eradication of the dead zone (not a sense of zone), which means that almost Tritec starting from 0 that is, open access to controlled areas, to open up to 90 degrees, the normal control than the general butterfly valve 2 times more than the maximum control over as much as 100:1. This valve Tritec used as a control to create good conditions, especially in large diameter, the high cost of cut-off valve, In addition, the cut-off valve can not achieve zero leakage, in need of emergency shutdown of the working conditions must be in the cut-off valve off the installation of the side valve, and control and Tritec set off in one, and its cost-effectiveness is extremely significant.
4, seat body structure
Three eccentric butterfly valve installed on the seat structure, there are two, mostly for convenience and the board installed in the butterfly, but the body is used Tritec seat construction, will be installed in the body on the valve seat. The advantage is, compared with the butterfly valve plate, thus greatly reducing the valve seat medium chance of direct contact, thus reducing the extent of erosion by the valve seat, extend the life of the valve seat.
5, thin film valve seat structure
Tritec the seat of stainless steel sheets stacked together with the graphite sheet, this structure can effectively prevent the media and the impact of micro-solid that may arise from thermal expansion of the sealing surface bite, even if the injury appears minor, it would not have leaked , which in the double eccentric butterfly valve or other three-eccentric butterfly valve is inconceivable.
6, can change the seal, Deputy
Vice-Tritec is unique sealing, not only can replace the valve seat body, and as a result of plate sealing surface and the Butterfly Garden is an independent board, butterfly plate sealing surface can be replaced, that is when the butterfly plate when the sealing surface damage, no longerand shipped back to factory or large-scale decomposition of the valve, simply change your butterfly plate sealing surface, which will not only greatly reduces maintenance costs, but also greatly reduces the maintenance and overhaul when the intensity and difficulty.
7, balance of fixed structure
Three eccentric butterfly valve from the sealing surface characteristics of shape, Tritec Vice fixed way of sealing a bolt fixed elliptical distribution, not only positioning accuracy, but also balanced so that each bolt has the force to stop due to stress arising from uneven distribution of Vice loose seal leakage.
8, the nature of fire-resistant structure
Many have claimed to have a fire-resistant valve construction, but the vast majority of valves in order to reduce leakage and the use of hard and soft structures the double seat, in fact, this is very dangerous. Because of fire soft seat seal incomplete combustion of the metal to support the valve seat will cause stress, deformation temperature, resulting in failure of fire-resistant function. Therefore, Europe and the United States is gradually excluded from the current name of the fire resistance of these valves. Tritrc because it is a zero-leakage, so do not need to refer to help soft-sealed, which is truly the essence of fire-resistant construction, and agreed there API607, API6FA and fire resistance test BS6755Part2 qualified certificate. This ensures that Tritec can be applied to petroleum, petrochemical and other hazardous area. In conservative Britain, its North Sea oil fields in all the key parts of the valves used in almost all been won Tritec is the best example of that.
9, high-sealed packing structure
Leakage in the valve issue, traditionally tend to focus on the leakage of the valve seat, that is, within the leak, to the neglect of the Department of leakage of filling materials, namely leakage. In fact, in the current environmental problems are growing in importance in contemporary society, the danger is far greater than with the leak leak has become an indisputable fact. Tritec three eccentric butterfly valves are back in transition, and its stem is only 90 ° rotary movement only, this valve, the valve stem moves, such as for the reciprocating motion of spiral multi-turn compared to the degree of wear and tear suffered by the Department of filler is low, relative to a long life, but also as a result of such Tritec in the packing seal to prevent external leakage of the structure, has taken the highest standards of design, which can be carried out in accordance with the specifications EPA21 external leak test, the sealing performance standards to ensure that the following 100ppm. In fact, the existing test results Tritec, in the case of Lloyd monitoring, external leakage values as low as 7ppm. Tritec means of these indicators can be a variety of chemicals in the field of toxic and hazardous pipelines in the medium to show their talents.
Application of three eccentric butterfly valve
To sum up, the three eccentric butterfly valves as the crystallization of the latest technology, a variety of valves Jan length short to avoid all kinds of valves, the majority of users will more and more attention and designers. Co., Ltd. Butterfly Valve Gate Pakistan Tritec, its level of maximum pressure level can reach 2500 pounds, the standard 48-inch diameter can be done, but also for folders, Ear, flange, ring then, butt welding, Jacket, the length of the various structures and so on to the corresponding, more as a result of Tritec great choice of materials, high temperature and various acids, alkalis and other corrosive media are also able to correspond freely. Especially in the large-diameter area, with its constantly zero leakage of the valve and replace the large ball valve, and similarly, the function of its excellent control, in-control valve also being constantly replaced by advantages in turn-off valve, the cut-off valve is bulky. As a fact, so far, Tritec has been used in, including China, oil and gas exploration, offshore platforms, oil refining, petrochemicals, inorganic chemicals, energy generation, such as major industrial sectors such as process control on an important pipeline.
We can offer more Knife Gate Valve Information.If you need us according your spcification to produce the Knife Gate Valve .
Need, please e-mail to valve401@gmail.com
Fault Analysis boiler valve safety valve (a)
1, Introduction
Safety valve is a very important protective valves, widely used in a variety of pressure vessels and piping systems, when the pressure in the system pressure exceeds the set value, it can automatically open to the media excess emissions into the atmosphere and going to ensure the pressure vessel and the safe operation of pipeline systems, to prevent accidents from occurring, and when the pressure back down to work within the system pressure, or slightly lower than the pressure of work and can shut down automatically. The reliability of safety valves to work directly related to the equipment and the safety of persons must be given due importance.
2, safety valve Common Cause analysis and solution
2.1, valve leakage
In the device under normal operating pressure, valve flap and valve seat sealing surface took place more than permitted levels of leakage, valve leakage will not only cause loss of media. In addition, the media will continue to leak to the destruction of hard sealing material, but the common safety valve sealing surface is metal on metal materials, while striving to do clean formation, but to bring pressure in the medium under other circumstances to definitely do not drain very difficult. Therefore, the working fluid is a steam safety valve, the required pressure value, if the naked eye can not see in the export side, it can not find leak, they maintain that sealing performance is qualified. Usually caused by valve leakage due mainly to the following three cases:
One scenario is that dirt impurities fell sealing surface, the sealing surface pad to live, resulting in a gap between the spool and the valve seat to valve leakage. Way to eliminate this fault is to remove all the dirt fall to the sealing surface and impurities, the general size of the repair in the boiler ready to shutdown, the first security door to do to run ram tests, if found to have carried out the dissolution of leakage after shutdown maintenance, if it is point furnace after running ram the security gate leakage tests found that the estimated result of this is the case, you can run for 20 minutes before the cooling ram to run the rudder once, on the sealing surface to erosion.
Another situation is that the sealing surface damage. Sealing surface damage caused by the following main reasons: First, bad sealing surface material. For example, in 3 ~ 9, the main security door furnace due to years of maintenance, the main security gate valve core and valve seat sealing surface generally has been developed very low, so that the hardness of the sealing surface also greatly reduced, resulting in sealing performance degradation, eliminating the The best way is to the phenomenon of the original sealing surface turning down, and then re-surfacing by drawing processing, to improve the surface hardness of the sealing surface. Note that in the process is bound to ensure the process quality, such as the sealing surface cracks, defects such as trachoma must go on to the turning re-processing. The new processing spool valve seat must comply with drawing requirements. Currently in use YST103 common steel electrode surfacing processing spool sealing surface effect will be better. Second, repair of poor quality, spool valve seat grinding not meet quality standards, to eliminate this failure is based on degree of injury after the use of grinding or turning the sealing surface grinding method of repair.
Another reason causing valve leakage is due to improper assembly or the part size inappropriate. Spool valve seat in the assembly process is not completely right or in conjunction with a translucent surface phenomenon, or a spool valve seat sealing surface too broad and is not conducive to sealing. Elimination method is to check with the space around the spool size and uniformity to ensure the top hole and the sealing surface spool Far from degrees, check the gap does not allow lifting valve core ministries; according to drawings called for a suitable reducing the width of the sealing surface to achieve effective sealing .
2.2, valve leakage with face
Refers to the upper and lower surface of the valve between the combination of the leakage phenomenon, the main reason for this leakage has the following aspects: First, with surface force bolt tight enough or tight side, resulting in poor combination of surface sealing. Elimination method is to adjust bolt tight edge, according to a certain time in the tight bolts right angle to a tight manner, preferably around the edges tight while measuring gap, the bolt tight to bear the fixed date, and make joint surface around the gap unanimously. Second, the combination of surface toothed valve gasket does not meet the standards. For example, the toothed gasket slight radial grooves, parallel degree of difference, too sharp or too sloping tooth defects can cause seal failure. So that combination of surface valve leakage. In the overhaul of spare parts at the time of good quality, use of standard tooth profile gasket on the occurrence of this phenomenon can be avoided. Third, body surface flatness with poor or live in a hard pad of impurities caused by seal failure. As the body of the combination of poor surface flatness caused by the leakage of body surface with the elimination method is to re-grind the valve with the disintegration of surface until it meets the quality standards. As the impurities cushion seal failure caused by living in the valve assembly combination of carefully cleaning the surface to avoid falling into impurity.
2.3, impulse action emperor safety valve safety valve does not move
This phenomenon is often referred to as the main security door and refuse to move.
Tripping the main security door in the boiler is running against is a very large, the equipment is a major hidden danger seriously affect the safe operation of equipment, once in the operation of pressure vessels and piping in the medium pressure in excess of rating, the main security door no action, super-pressure operation of the equipment can easily result in equipment damage and major incidents.
In the analysis of the main security door refused to move because, first an analysis of the action principle of the main security door. Shown in Figure 1, when the pressure within the pressure vessel rose to the entire impulse pressure relief valve, safety valve impulse action, medium from the container through the main valve piston pipeline rushed indoors, in the Pistons will have a tiny room expansion Buck, if this time the piston chamber pressure of P1, the piston throttling area of Shs, this time acting on the piston on the f1 as follows:
f1 = P1 × Shs ... ... ... ... ... ... ... ... (1)
If the media inside the pressure vessels at this time the pressure for P2, spool area of Sfx, then the media at this time an upward force on the spool f2 as follows:
f2 = P2 × Shx ?..............( 2)
Usually a safety valve piston diameter than the large diameter spool, so equation (1) and type (2) Shs> Sfx? P1 ≈ P2
If the spring through the stem upward pull on the spool set f3 and to moving parts and the friction between the fixed parts (mainly between the piston and piston chamber friction) set fm, the action of the main security door pre-conditions: only acting on the piston slightly greater than the force acting on spool on the f1 to f2 and the spring force upward through the stem upward pull on the spool f3 and the moving parts and the friction between the fixed parts (mainly the piston and the the friction between the piston chamber) fm sum, that is: f1> f2 + f3 + fm to start when the main security door.
Through practice, the main security door refused to move primarily to the following three factors:
First, there is jamming the valve phenomena of moving parts.
This may be due to improper assembly, dirt and impurities mixed or parts corrosion; piston chamber surface finish is poor, surface damage, there are grooves hard points, such as deficiencies. This allows moving parts and fixed parts fm between the friction increases, other conditions remain unchanged under the f1 <f2 + f3 + fm Therefore, the main security doors refused to move.
For example, in 2001, before the No. 3 furnace overhaul of the main security door overheating ram test run, there have been the main security doors refused to move. Maintenance inspection found that when the disintegration of the piston there is plenty of rust and dirt and impurities, the piston in the piston can not exercise indoors, resulting in the main security doors refused to move.
Maintenance when piston ring and piston expansion chamber had rust treatment room on the piston grooves and other defects of the grinding, assembly before the piston interior wall evenly coated with lead powder, and strictly in sequence of the valve assembly. In the boiler water pressure tests, flushing of the pulse tube, and then the main security door and the impulse valve connected to the last point furnace overhaul safety valve when running ram test again as usual.
Second, is the main security door leaks a large quantity of the piston chamber. When the valve piston chamber large amount of gas leakage, the equation (1) the role of the f1 a smaller force on the piston, other conditions remain unchanged under the f1 <f2 + f3 + fm Therefore, the main security doors refused to move. Large amount of gas leakage caused by the piston chamber and the valve itself is the main reason for the air tightness and piston rings do not meet size requirements or piston ring wear and tear is too large not meet sealing requirements are.
For example, 3 ~ 9, keeper of the piston valve is a piston ring quality requirements of the edges and corners should be smooth, free state open space of not more than 14, assembled open space △ = 1 ~ 1.25, piston and piston chamber space B = 0.12 ~ 0.18, piston rings and piston chamber gap of S = 0.08 ~ 0.12, piston rings good contact with the piston chamber, the transmittance should be no larger than the circumference of a / 6. Interior of the piston requirement is that the interior of the groove depth of the piston shall not exceed 0.08 ~ 0.1mm, the ellipticity does not exceed 0.1mm, taper degree of not more than 0.1mm, should be smooth without scratches, but the disintegration of each furnace maintenance check found that the main Security door piston rings, piston and piston chamber maintenance procedures do not meet the requirements, the current general piston and piston chamber gap are S ≥ 0.20, and the defects in the surface of the piston chamber is more serious, seriously affected the piston chamber of the steam density nature, resulting in leakage of steam too large piston chamber.
Way to eliminate this defect are: piston interior surface treatment, to replace qualified piston and piston rings, where the impulse throttle safety device system, off a small throttle opening, increasing the access to the main security door into the piston chamber steam, in the conditions allow, under the impulse can also be a safety valve by increasing the stroke to increase access to the main security door into the piston chamber means to promote the main steam safety valve action.
ball valve Trunnion Mounted Ball Valve Floating Ball Valve Top Entry Ball Valve Three way ball valve V Type Ball Valve
We can offer more Knife Gate Valve Information.If you need us according your spcification to produce the Knife Gate Valve .
Need, please e-mail to valve401@gmail.com
Safety valve is a very important protective valves, widely used in a variety of pressure vessels and piping systems, when the pressure in the system pressure exceeds the set value, it can automatically open to the media excess emissions into the atmosphere and going to ensure the pressure vessel and the safe operation of pipeline systems, to prevent accidents from occurring, and when the pressure back down to work within the system pressure, or slightly lower than the pressure of work and can shut down automatically. The reliability of safety valves to work directly related to the equipment and the safety of persons must be given due importance.
2, safety valve Common Cause analysis and solution
2.1, valve leakage
In the device under normal operating pressure, valve flap and valve seat sealing surface took place more than permitted levels of leakage, valve leakage will not only cause loss of media. In addition, the media will continue to leak to the destruction of hard sealing material, but the common safety valve sealing surface is metal on metal materials, while striving to do clean formation, but to bring pressure in the medium under other circumstances to definitely do not drain very difficult. Therefore, the working fluid is a steam safety valve, the required pressure value, if the naked eye can not see in the export side, it can not find leak, they maintain that sealing performance is qualified. Usually caused by valve leakage due mainly to the following three cases:
One scenario is that dirt impurities fell sealing surface, the sealing surface pad to live, resulting in a gap between the spool and the valve seat to valve leakage. Way to eliminate this fault is to remove all the dirt fall to the sealing surface and impurities, the general size of the repair in the boiler ready to shutdown, the first security door to do to run ram tests, if found to have carried out the dissolution of leakage after shutdown maintenance, if it is point furnace after running ram the security gate leakage tests found that the estimated result of this is the case, you can run for 20 minutes before the cooling ram to run the rudder once, on the sealing surface to erosion.
Another situation is that the sealing surface damage. Sealing surface damage caused by the following main reasons: First, bad sealing surface material. For example, in 3 ~ 9, the main security door furnace due to years of maintenance, the main security gate valve core and valve seat sealing surface generally has been developed very low, so that the hardness of the sealing surface also greatly reduced, resulting in sealing performance degradation, eliminating the The best way is to the phenomenon of the original sealing surface turning down, and then re-surfacing by drawing processing, to improve the surface hardness of the sealing surface. Note that in the process is bound to ensure the process quality, such as the sealing surface cracks, defects such as trachoma must go on to the turning re-processing. The new processing spool valve seat must comply with drawing requirements. Currently in use YST103 common steel electrode surfacing processing spool sealing surface effect will be better. Second, repair of poor quality, spool valve seat grinding not meet quality standards, to eliminate this failure is based on degree of injury after the use of grinding or turning the sealing surface grinding method of repair.
Another reason causing valve leakage is due to improper assembly or the part size inappropriate. Spool valve seat in the assembly process is not completely right or in conjunction with a translucent surface phenomenon, or a spool valve seat sealing surface too broad and is not conducive to sealing. Elimination method is to check with the space around the spool size and uniformity to ensure the top hole and the sealing surface spool Far from degrees, check the gap does not allow lifting valve core ministries; according to drawings called for a suitable reducing the width of the sealing surface to achieve effective sealing .
2.2, valve leakage with face
Refers to the upper and lower surface of the valve between the combination of the leakage phenomenon, the main reason for this leakage has the following aspects: First, with surface force bolt tight enough or tight side, resulting in poor combination of surface sealing. Elimination method is to adjust bolt tight edge, according to a certain time in the tight bolts right angle to a tight manner, preferably around the edges tight while measuring gap, the bolt tight to bear the fixed date, and make joint surface around the gap unanimously. Second, the combination of surface toothed valve gasket does not meet the standards. For example, the toothed gasket slight radial grooves, parallel degree of difference, too sharp or too sloping tooth defects can cause seal failure. So that combination of surface valve leakage. In the overhaul of spare parts at the time of good quality, use of standard tooth profile gasket on the occurrence of this phenomenon can be avoided. Third, body surface flatness with poor or live in a hard pad of impurities caused by seal failure. As the body of the combination of poor surface flatness caused by the leakage of body surface with the elimination method is to re-grind the valve with the disintegration of surface until it meets the quality standards. As the impurities cushion seal failure caused by living in the valve assembly combination of carefully cleaning the surface to avoid falling into impurity.
2.3, impulse action emperor safety valve safety valve does not move
This phenomenon is often referred to as the main security door and refuse to move.
Tripping the main security door in the boiler is running against is a very large, the equipment is a major hidden danger seriously affect the safe operation of equipment, once in the operation of pressure vessels and piping in the medium pressure in excess of rating, the main security door no action, super-pressure operation of the equipment can easily result in equipment damage and major incidents.
In the analysis of the main security door refused to move because, first an analysis of the action principle of the main security door. Shown in Figure 1, when the pressure within the pressure vessel rose to the entire impulse pressure relief valve, safety valve impulse action, medium from the container through the main valve piston pipeline rushed indoors, in the Pistons will have a tiny room expansion Buck, if this time the piston chamber pressure of P1, the piston throttling area of Shs, this time acting on the piston on the f1 as follows:
f1 = P1 × Shs ... ... ... ... ... ... ... ... (1)
If the media inside the pressure vessels at this time the pressure for P2, spool area of Sfx, then the media at this time an upward force on the spool f2 as follows:
f2 = P2 × Shx ?..............( 2)
Usually a safety valve piston diameter than the large diameter spool, so equation (1) and type (2) Shs> Sfx? P1 ≈ P2
If the spring through the stem upward pull on the spool set f3 and to moving parts and the friction between the fixed parts (mainly between the piston and piston chamber friction) set fm, the action of the main security door pre-conditions: only acting on the piston slightly greater than the force acting on spool on the f1 to f2 and the spring force upward through the stem upward pull on the spool f3 and the moving parts and the friction between the fixed parts (mainly the piston and the the friction between the piston chamber) fm sum, that is: f1> f2 + f3 + fm to start when the main security door.
Through practice, the main security door refused to move primarily to the following three factors:
First, there is jamming the valve phenomena of moving parts.
This may be due to improper assembly, dirt and impurities mixed or parts corrosion; piston chamber surface finish is poor, surface damage, there are grooves hard points, such as deficiencies. This allows moving parts and fixed parts fm between the friction increases, other conditions remain unchanged under the f1 <f2 + f3 + fm Therefore, the main security doors refused to move.
For example, in 2001, before the No. 3 furnace overhaul of the main security door overheating ram test run, there have been the main security doors refused to move. Maintenance inspection found that when the disintegration of the piston there is plenty of rust and dirt and impurities, the piston in the piston can not exercise indoors, resulting in the main security doors refused to move.
Maintenance when piston ring and piston expansion chamber had rust treatment room on the piston grooves and other defects of the grinding, assembly before the piston interior wall evenly coated with lead powder, and strictly in sequence of the valve assembly. In the boiler water pressure tests, flushing of the pulse tube, and then the main security door and the impulse valve connected to the last point furnace overhaul safety valve when running ram test again as usual.
Second, is the main security door leaks a large quantity of the piston chamber. When the valve piston chamber large amount of gas leakage, the equation (1) the role of the f1 a smaller force on the piston, other conditions remain unchanged under the f1 <f2 + f3 + fm Therefore, the main security doors refused to move. Large amount of gas leakage caused by the piston chamber and the valve itself is the main reason for the air tightness and piston rings do not meet size requirements or piston ring wear and tear is too large not meet sealing requirements are.
For example, 3 ~ 9, keeper of the piston valve is a piston ring quality requirements of the edges and corners should be smooth, free state open space of not more than 14, assembled open space △ = 1 ~ 1.25, piston and piston chamber space B = 0.12 ~ 0.18, piston rings and piston chamber gap of S = 0.08 ~ 0.12, piston rings good contact with the piston chamber, the transmittance should be no larger than the circumference of a / 6. Interior of the piston requirement is that the interior of the groove depth of the piston shall not exceed 0.08 ~ 0.1mm, the ellipticity does not exceed 0.1mm, taper degree of not more than 0.1mm, should be smooth without scratches, but the disintegration of each furnace maintenance check found that the main Security door piston rings, piston and piston chamber maintenance procedures do not meet the requirements, the current general piston and piston chamber gap are S ≥ 0.20, and the defects in the surface of the piston chamber is more serious, seriously affected the piston chamber of the steam density nature, resulting in leakage of steam too large piston chamber.
Way to eliminate this defect are: piston interior surface treatment, to replace qualified piston and piston rings, where the impulse throttle safety device system, off a small throttle opening, increasing the access to the main security door into the piston chamber steam, in the conditions allow, under the impulse can also be a safety valve by increasing the stroke to increase access to the main security door into the piston chamber means to promote the main steam safety valve action.
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The use of emergency shutdown valves should pay attention to several issues
Emergency shutdown valve is in recent years developed a new product. In engineering applications are increasing. In the installation process, we also found some problems, there are some construction problems, there are some design problems. A good product not only to better the quality of the product itself, the most important is to let everyone know it, know it, and the rational use of it, in order to play its biggest role.
One, why use the emergency shut-off valve
As you know, has always been the fire pipe network and life management are two water supply systems, water supply by two pumping systems, respectively, from the pump to the building for a long distance from the Road to piped water. Road due to the laying of such a large workload of pipeline construction, pipeline materials, double, and maintenance of a pipeline when the identification is also a lot of inconvenience; second, fire pipes for many years not to use, easy to rust, wall panels and interfaces for corrosion thinning, usually do not have no pressure, while the case of fire, a sudden pressure increase inside the tubes, easy to burst, resulting in fire system can not supply. Third, the Shanghai to promote water pump pumping directly from the municipal pipe network is no longer underground pool. This will not only eliminate the cost of the construction of the pool, while avoiding secondary pollution of the water. Maintaining the cleanliness of water sources to ensure people's health is the most important one. Because of the advantages of these areas, so the products are gradually being everyone's welcome.
Second, emergency shut-off valve works emergency shutdown valve is in a hydraulic control valve. Is from the main valve, throttle, guided valves, pressure gauges and other pipe fittings formed to take over. When the main valve inlet pressure below the set pressure valve guide, the guide valve is turned on at this time, the main valve cover chamber pressure and the main valve outlet pressure equal to, import and export existing differential pressure, flow through the valve port by exports out of . When the fire pump starting, or pump-pressure increases, more than lead valve set pressure, the import pass by the main valve guide valve control pipe pressure increases, the role of the spring pressure on the downward pressed to drive spool down, so that guide valve closed, this time the main valve inlet pressure through the throttle valve continuously added to the main valve cover chamber, due to valve flap downward pressure being greater than the upward thrust, the main valve closed. Please note that the key point is that the inlet pressure is less than set pressure of the valve has been turned on, inlet pressure is greater than set pressure, the valve is turned off. There are so many designers to the misconception that as long as the emergency shutdown valve installed, it will pass, do not say what conditions, it would be wrong.
Third, engineering problems we have encountered during the actual installation and testing of many unreasonable to propose for discussion. Plume is located in Shanghai Pudong Road there is a residential pump room on the ground floor, three 12-storey layer and two eight-story, floor 2.8 meters high, life pumps fire pumps are DN80, living pump head 53 meters, fire pump head 60 meters, Flow 10L / S, the water supply sub-Wu Lu, DN80 pipe into the rooftop water tank. From DN80 pump at the same time for the Wu Lu DN80 pipe, so pressure is not high, barely into the tank. Emergency shutdown valve to the pressure set at 0.5MPa, while for the Wu Lu water, pressure, no more than 0.5MPa, could only supply water to the water tank. However, if there are four water tank is full, liquid level control valve on the tank off, leaving only a tank of water still dissatisfied with pay, at this time the pressure will rise, more than 0.5MPa, emergency shut-off valve will be closed, The remaining one can not recharge the tank. In order to smoothly supply water tanks for every one, we need to be stable at the pressure 0.45MPa, so that is less than 0.5MPa, will not lead to the closure. This requires that pumps life add a pressure relief valve. Most units now, life is not set pump pressure relief valve. Some units use the electric contact pressure gauge, when the water pressure is increased automatically when the trip exceeds 0.5MPa, water pumps stop functioning, so that a single tank is still not solve the problem of replenishment.
The second problem is when the fire pump start, all of the emergency shutdown valve is open. DN80 pump sub-Wu Lu DN80 plumbing, this time, if dissatisfied with the tank water, water pressure would not increase, unlikely to exceed 0.5MPa, until the pool filled, liquid level control valve closed, pressure can rise. Here the designer should consider increasing the pump capacity, or reduce the pipe diameter, the two should be at least a difference of two files, such as water pumps replaced DN100, Wulu pipes replaced DN65, at this time the pressure can be more than 0.5MPa, since to close the role, in order to bring the water to the building fire service delivery. Another example, in Shanghai, there is a residential district Kongjiang DN100 fire pump, six road pipe DN80, still can not shut down, so multi-channel pumps and water pipes should be a difference of two files is appropriate.
The third problem is that the drainage system pump house, pressure relief valve discharge water should be discharged into the fire pool, or sewer and should not be ranked in a narrow ditch Ming. Or to cite the example described above, in the debugging Wu Lu pipes, all the way all the way to gradually shut down, resulting pump the water out of wholly on the pressure relief valve to vent the basement, drainage pump is far less than the fire pump, underground pumping station results flooded. The best option is to pump life and fire safety have adopted variable frequency pump, when debugging is not a constant pressure flow. Quantitative pumps or pressure relief valve can also be added, but the pressure relief valve necessary to the pool or in conjunction with the sewer pipe, sewer diameter than the inlet freshman to second gear. After the emergency shutdown valve valve through the user's program is better. Pipe network and live in fire between the pipe network is advisable to increase an anti-fouling cut off valve to prevent the return of contaminated fire water for domestic use. Figure 3.
The fourth question, the installation location of choice. So far, most users the location of emergency shutdown valves installed on the dumb wells. There is an emergency shutdown valve users to set up the staircase, I think on a more reasonable under the stairs for easy commissioning and maintenance. If on the dumb wells should allow sufficient space for maintenance, and some dumb well an area of only 40 × 60cm2, and has more than 1 meter deep, space is too small maintenance staff simply can not debug. And valves at both ends there is no expansion joints or soft joints, if the required repairs can not be removed again Zhuangshang Qu. Proposed dumb Wells area 60 × 80cm2, the depth should not be too deep to seal covers do not touch after the valve is appropriate. In addition, the need to add flexible connector or valve with a pick elbow.
The fifth issue, piping should be washed clean before opening. Debugging process, we found that emergency shutdown valve can not be closed, eliminating stress factors, suspected to have gravel in the body of memory to stay, after checking the valve 12 the majority of Taiwan have gravel retention, including two to the next body cavity filled. Therefore, the installation of emergency shut down valve should be cleaned before the pipeline, in order to ensure that all the valves work properly.
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One, why use the emergency shut-off valve
As you know, has always been the fire pipe network and life management are two water supply systems, water supply by two pumping systems, respectively, from the pump to the building for a long distance from the Road to piped water. Road due to the laying of such a large workload of pipeline construction, pipeline materials, double, and maintenance of a pipeline when the identification is also a lot of inconvenience; second, fire pipes for many years not to use, easy to rust, wall panels and interfaces for corrosion thinning, usually do not have no pressure, while the case of fire, a sudden pressure increase inside the tubes, easy to burst, resulting in fire system can not supply. Third, the Shanghai to promote water pump pumping directly from the municipal pipe network is no longer underground pool. This will not only eliminate the cost of the construction of the pool, while avoiding secondary pollution of the water. Maintaining the cleanliness of water sources to ensure people's health is the most important one. Because of the advantages of these areas, so the products are gradually being everyone's welcome.
Second, emergency shut-off valve works emergency shutdown valve is in a hydraulic control valve. Is from the main valve, throttle, guided valves, pressure gauges and other pipe fittings formed to take over. When the main valve inlet pressure below the set pressure valve guide, the guide valve is turned on at this time, the main valve cover chamber pressure and the main valve outlet pressure equal to, import and export existing differential pressure, flow through the valve port by exports out of . When the fire pump starting, or pump-pressure increases, more than lead valve set pressure, the import pass by the main valve guide valve control pipe pressure increases, the role of the spring pressure on the downward pressed to drive spool down, so that guide valve closed, this time the main valve inlet pressure through the throttle valve continuously added to the main valve cover chamber, due to valve flap downward pressure being greater than the upward thrust, the main valve closed. Please note that the key point is that the inlet pressure is less than set pressure of the valve has been turned on, inlet pressure is greater than set pressure, the valve is turned off. There are so many designers to the misconception that as long as the emergency shutdown valve installed, it will pass, do not say what conditions, it would be wrong.
Third, engineering problems we have encountered during the actual installation and testing of many unreasonable to propose for discussion. Plume is located in Shanghai Pudong Road there is a residential pump room on the ground floor, three 12-storey layer and two eight-story, floor 2.8 meters high, life pumps fire pumps are DN80, living pump head 53 meters, fire pump head 60 meters, Flow 10L / S, the water supply sub-Wu Lu, DN80 pipe into the rooftop water tank. From DN80 pump at the same time for the Wu Lu DN80 pipe, so pressure is not high, barely into the tank. Emergency shutdown valve to the pressure set at 0.5MPa, while for the Wu Lu water, pressure, no more than 0.5MPa, could only supply water to the water tank. However, if there are four water tank is full, liquid level control valve on the tank off, leaving only a tank of water still dissatisfied with pay, at this time the pressure will rise, more than 0.5MPa, emergency shut-off valve will be closed, The remaining one can not recharge the tank. In order to smoothly supply water tanks for every one, we need to be stable at the pressure 0.45MPa, so that is less than 0.5MPa, will not lead to the closure. This requires that pumps life add a pressure relief valve. Most units now, life is not set pump pressure relief valve. Some units use the electric contact pressure gauge, when the water pressure is increased automatically when the trip exceeds 0.5MPa, water pumps stop functioning, so that a single tank is still not solve the problem of replenishment.
The second problem is when the fire pump start, all of the emergency shutdown valve is open. DN80 pump sub-Wu Lu DN80 plumbing, this time, if dissatisfied with the tank water, water pressure would not increase, unlikely to exceed 0.5MPa, until the pool filled, liquid level control valve closed, pressure can rise. Here the designer should consider increasing the pump capacity, or reduce the pipe diameter, the two should be at least a difference of two files, such as water pumps replaced DN100, Wulu pipes replaced DN65, at this time the pressure can be more than 0.5MPa, since to close the role, in order to bring the water to the building fire service delivery. Another example, in Shanghai, there is a residential district Kongjiang DN100 fire pump, six road pipe DN80, still can not shut down, so multi-channel pumps and water pipes should be a difference of two files is appropriate.
The third problem is that the drainage system pump house, pressure relief valve discharge water should be discharged into the fire pool, or sewer and should not be ranked in a narrow ditch Ming. Or to cite the example described above, in the debugging Wu Lu pipes, all the way all the way to gradually shut down, resulting pump the water out of wholly on the pressure relief valve to vent the basement, drainage pump is far less than the fire pump, underground pumping station results flooded. The best option is to pump life and fire safety have adopted variable frequency pump, when debugging is not a constant pressure flow. Quantitative pumps or pressure relief valve can also be added, but the pressure relief valve necessary to the pool or in conjunction with the sewer pipe, sewer diameter than the inlet freshman to second gear. After the emergency shutdown valve valve through the user's program is better. Pipe network and live in fire between the pipe network is advisable to increase an anti-fouling cut off valve to prevent the return of contaminated fire water for domestic use. Figure 3.
The fourth question, the installation location of choice. So far, most users the location of emergency shutdown valves installed on the dumb wells. There is an emergency shutdown valve users to set up the staircase, I think on a more reasonable under the stairs for easy commissioning and maintenance. If on the dumb wells should allow sufficient space for maintenance, and some dumb well an area of only 40 × 60cm2, and has more than 1 meter deep, space is too small maintenance staff simply can not debug. And valves at both ends there is no expansion joints or soft joints, if the required repairs can not be removed again Zhuangshang Qu. Proposed dumb Wells area 60 × 80cm2, the depth should not be too deep to seal covers do not touch after the valve is appropriate. In addition, the need to add flexible connector or valve with a pick elbow.
The fifth issue, piping should be washed clean before opening. Debugging process, we found that emergency shutdown valve can not be closed, eliminating stress factors, suspected to have gravel in the body of memory to stay, after checking the valve 12 the majority of Taiwan have gravel retention, including two to the next body cavity filled. Therefore, the installation of emergency shut down valve should be cleaned before the pipeline, in order to ensure that all the valves work properly.
ball valve Trunnion Mounted Ball Valve Floating Ball Valve Top Entry Ball Valve ball valve V Type Ball Valve
We can offer more Knife Gate Valve Information.If you need us according your spcification to produce the Knife Gate Valve .
Need, please e-mail to valve401@gmail.com
On the fire safety valve
First, the importance of fire safety control valve
In the chemical, oil and other automation systems in the event of a fire, if the system, certain devices can be cut off flammable fluid in a timely manner throughout the road leading to the fire, it would be possible to avoid the fire spreading directly from the fire zone around the plant caused by losses.
Regulating valve is an automated system is an important integral part of the installed on-site control flow path, so somewhere in the fire when it was cut off to prevent flammable fluid flow path leading to the fire throughout the territory of major equipment. In the fire case, it is open or closed is very critical. As the control valve from the control room of the regulator to conduct self-control, not manually, so fire the main features of the valve should be: able to withstand the thermostat while the short-term work, or turn off when put up with hardships so that leakage should be minimal. The fire safety of the valve should be seen to be a great need to consider the performance, hoping to rise to the persons concerned attention.
Second, the standard fire control valve
What kind of valve is the fire valve then? Abroad, referred to the fire valve (fire-safe valve), right valve of the definition of a lot of fire instead of unity, such a definition in the industry is still a lack of clear requirements. So far, still no single test or definition can clearly determine whether a valve fire.
Large number of industrial society, oil companies, insurance companies, valve manufacturers, as well as the United Kingdom, the United States, the provisions of the relevant agencies have a variety of testing methods. However, the measured valve types and the main test specifications with the test methods differ. Debate on the combustion valve testing continues, and some tried to approach two or more integrated as a complete way, but still not conclusive. How can we be accurate to the fire damper subglottic defined? This is what we need to study the issue, first of all should study the soft valve seat standards.
Some people think that the fire will not melt the metal gate valve and ball valve (globe valve) is the fire dampers. The design and structure of these valves can guarantee it on fire before and after are metals and metal (metal-to-metal) contact, which avoids the flammable fluid into the fire that in the. However, the metal valve seat at the fire before the operation, the seal is not good. As the leakage is very small, so most of the established fire safety standards are also permitted.
User requirements during normal operation the valve is both a fine seal, but also has fire resistant. Many valve manufacturers as early as 15 to 20 years ago to try to resolve this complex issue, they have developed a variety of "soft" or "hard" seal components, all of which caught fire two types of components, the latter can keep metal face contact seal.
Hard seat is made of metal or alloy, and its own can withstand high temperatures. Soft seat with rubber, plastic or melting point lower than 700 � (about 370 ℃) of elastic material, soft seat can be destroyed after the fire, then by virtue of the system pressure, the valve plate rotate, spring force or the role of self-gravity to maintain contact with metal surface. However, many soft-seat valve in the safety of combustion is not ideal. If the elasticity of the valve seat can not be totally destroyed in the fire, it can not form a metal surface contact. The following table summarizes the soft seat, including several fire test, from the table view, the various tests have different standards for the valve test specifications for analysis and comparison, you can learn which five kinds of standards are more stringent. Must be pointed out, the American Petroleum Institute Standard API607 "soft-sealing valve combustion test (1977)" is a provisional standard, it has all of 16 inches below the ball apply. Later, the second edition of the standard API RP6F was amended to require more stringent.
Provided by different manufacturers of valves can only be consistent with one or two described in the following table the fire safety standards, such as Rockwell (Rock well) provided by the company fire plunger valve and ball valves can only be consistent with API607 and API RP6F 2 kinds of standards, others can only be provided in line with some other standard valves.
Third, specific measures for fire control valve
1, valve body of fire
Although the fire safety valve and some have different views and formulate the specifications of different test methods are also different, but how to fire the valve should have a more consistent view. The valve body, it should have the following three properties, but also to ensure the performance of these three points should be taken to a variety of specific measures.
(1) The minimum amount of internal leakage. To ensure this performance, we should first take into account the valve core and valve seat of the metal surface contact, in the fire, or fire it, the valve being in heat, regardless of their enclosed structure, the spring force and applied pressure on how these changes are should ensure that, should think that this is the key to ensure its precision closed.
(2) The minimum amount of external leakage. In order to minimize the external leakage, the methods being considered are: use of stem sealing material can be fire, avoid using large valve gasket-style links.
(3) a continuous operational. Still work properly after combustion valve, naturally, with anti-deformation capability, resistant to damage.
In order to ensure that fire prevention valve performance, many manufacturers have been various attempts. For example, they bandaged the valve on the cover of the multi-layered mat, using refractory bricks box, so that the valve separating the outside world. However, the above methods are less likely to be considered satisfactory because each time the valve repair should be apart, build on. The same day, due to valve installation location restrictions, it may not be this way.
At present a more satisfactory way is to use a fire bag, it can be put on within a few minutes, maintenance can easily be opened. Bags of material containing multi-layered ceramic fiber (eramic fiber) or glass fiber (fiberglass) bind tightly tied with nylon and used vinyl coated stainless steel wires are properly tied in the device. In general questions, does not need to change the location of pipelines, installation space is small, through the test in 2000 � flame burning for 30 minutes, the valve is still not damaged, the performance is satisfactory.
2, the executing agency of the fire
As the implementing agency and direct control over the location of the valve, so need careful study. In order to close the valve to maintain a timely manner, and therefore easier to fire occasions are often used in pneumatic diaphragm spring steel (iron) executing agencies, mainly the use of low melting point, this feature patch. Fire, due to the low melting point membrane damage very quickly, so spring movement, so that the valve in the closed position. The use of heat-sensitive fusible plug-type holes to reduce the pressure of pneumatic system, particularly suitable for reciprocating piston-type spring executing agency.
A serious fire can change the characteristics of metal parts, there is cause metal tempering features softened and lost, and some metal actually melted. Spring force of the size and tempering characteristics are directly related to whether the burning of residual spring force sufficient to keep the valve position, the need for implementing agencies to conduct combustion tests can prove.
Right valve, the combustion is often necessary to keep the remainder of spring torque valve closed position, closing the force required to appear much smaller than the original output power of the implementing agencies. In the spherical valve body on the implementation of the remaining spring force is very important. In the same pipeline pressure, balanced than the unbalanced ball valve ball valve spring force required to be smaller, so use fire-prone places, people are willing to use a balanced-type ball valve.
To make operation even after burning of the implementing agencies on the need to protect the springs, to make it from the flame annealing effects. Protection of springs can be used three kinds of methods: thermal insulation material, using sprinklers or fire protection coating. Including the multi-layer insulated the tropics, the use of thermal insulation cover or use fire bag, so that implementing agencies in the running for half an hour after the fire. But this trick and sealing method is more cumbersome and inconvenient, accounting for a large space. In the implementing agencies at the top fitted with sprinklers, which has increased the installation and maintenance costs; and often without water due to fire, nor to the sprinkler water supply. Enforcement bodies may be coated with a epoxy-based (epoxy-based) expansion of thin material, so that normal operation of the executing agency. In a combustion experiment, due to the protection of paint, although the fire temperatures as high as 1400 ~ 1700 �, implementing agencies able to work 42 minutes. Test of the spring-loaded with 1600 pounds of cast iron implementing agencies, about 7 feet long, 12-inch cylinder bore, using nine propane torch to burn spray. Throughout the combustion process in the executive body of the spring back and forth once every minute, after the spring burn to reduce the output torque is only 6%, and was mainly due to decreased precision bearings, the friction caused by the increase. Tests showed that burning flame springs are not subject to the impact of the piston and rod seals also remain, such as old, sealed well. After the completion of the pilot, the executive body immersed in cold water. Simulate the role of high-temperature shell suddenly cold. Tests showed that the executing agency of the housing and internal parts are not due to a sudden cooling by the harmful effects.
Expansion coating is cast with me, like using concrete, as when wiping in the field, we must be careful not to wipe seals live in parts, this would allow maintenance of inconvenience. When the coating when it dries to form a hard, impermeable sealing layer. Jamesbury company also built the main body of the disk board and cabinet, respectively, coated, so that maintenance can be opened to move board. If the executing agency is the aluminum body, that the use of paint is difficult to fire because of the low melting point of aluminum (1033 ~ 1150 �), higher than the melting point of the hydrocarbon mixture flame, parts will be failure, the valve can not be closed.
Finally, we need introduce a link protection method. Reciprocating spring-loaded devices from different manufacturers supply valve, these spring-loaded devices in a "pending attack" position, it can only fire when the firing, firing an automatic when the valve to move to the insurance position. There will be holding components can be used fusible link, connecting rod or electric rod brittle. Electric rod and easy to link the role of melting, as heat can be started. Dangerous moment in the fire, which was immediately smoke servo rod device is disconnected, so that the valve is in the insurance bit.
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In the chemical, oil and other automation systems in the event of a fire, if the system, certain devices can be cut off flammable fluid in a timely manner throughout the road leading to the fire, it would be possible to avoid the fire spreading directly from the fire zone around the plant caused by losses.
Regulating valve is an automated system is an important integral part of the installed on-site control flow path, so somewhere in the fire when it was cut off to prevent flammable fluid flow path leading to the fire throughout the territory of major equipment. In the fire case, it is open or closed is very critical. As the control valve from the control room of the regulator to conduct self-control, not manually, so fire the main features of the valve should be: able to withstand the thermostat while the short-term work, or turn off when put up with hardships so that leakage should be minimal. The fire safety of the valve should be seen to be a great need to consider the performance, hoping to rise to the persons concerned attention.
Second, the standard fire control valve
What kind of valve is the fire valve then? Abroad, referred to the fire valve (fire-safe valve), right valve of the definition of a lot of fire instead of unity, such a definition in the industry is still a lack of clear requirements. So far, still no single test or definition can clearly determine whether a valve fire.
Large number of industrial society, oil companies, insurance companies, valve manufacturers, as well as the United Kingdom, the United States, the provisions of the relevant agencies have a variety of testing methods. However, the measured valve types and the main test specifications with the test methods differ. Debate on the combustion valve testing continues, and some tried to approach two or more integrated as a complete way, but still not conclusive. How can we be accurate to the fire damper subglottic defined? This is what we need to study the issue, first of all should study the soft valve seat standards.
Some people think that the fire will not melt the metal gate valve and ball valve (globe valve) is the fire dampers. The design and structure of these valves can guarantee it on fire before and after are metals and metal (metal-to-metal) contact, which avoids the flammable fluid into the fire that in the. However, the metal valve seat at the fire before the operation, the seal is not good. As the leakage is very small, so most of the established fire safety standards are also permitted.
User requirements during normal operation the valve is both a fine seal, but also has fire resistant. Many valve manufacturers as early as 15 to 20 years ago to try to resolve this complex issue, they have developed a variety of "soft" or "hard" seal components, all of which caught fire two types of components, the latter can keep metal face contact seal.
Hard seat is made of metal or alloy, and its own can withstand high temperatures. Soft seat with rubber, plastic or melting point lower than 700 � (about 370 ℃) of elastic material, soft seat can be destroyed after the fire, then by virtue of the system pressure, the valve plate rotate, spring force or the role of self-gravity to maintain contact with metal surface. However, many soft-seat valve in the safety of combustion is not ideal. If the elasticity of the valve seat can not be totally destroyed in the fire, it can not form a metal surface contact. The following table summarizes the soft seat, including several fire test, from the table view, the various tests have different standards for the valve test specifications for analysis and comparison, you can learn which five kinds of standards are more stringent. Must be pointed out, the American Petroleum Institute Standard API607 "soft-sealing valve combustion test (1977)" is a provisional standard, it has all of 16 inches below the ball apply. Later, the second edition of the standard API RP6F was amended to require more stringent.
Provided by different manufacturers of valves can only be consistent with one or two described in the following table the fire safety standards, such as Rockwell (Rock well) provided by the company fire plunger valve and ball valves can only be consistent with API607 and API RP6F 2 kinds of standards, others can only be provided in line with some other standard valves.
Third, specific measures for fire control valve
1, valve body of fire
Although the fire safety valve and some have different views and formulate the specifications of different test methods are also different, but how to fire the valve should have a more consistent view. The valve body, it should have the following three properties, but also to ensure the performance of these three points should be taken to a variety of specific measures.
(1) The minimum amount of internal leakage. To ensure this performance, we should first take into account the valve core and valve seat of the metal surface contact, in the fire, or fire it, the valve being in heat, regardless of their enclosed structure, the spring force and applied pressure on how these changes are should ensure that, should think that this is the key to ensure its precision closed.
(2) The minimum amount of external leakage. In order to minimize the external leakage, the methods being considered are: use of stem sealing material can be fire, avoid using large valve gasket-style links.
(3) a continuous operational. Still work properly after combustion valve, naturally, with anti-deformation capability, resistant to damage.
In order to ensure that fire prevention valve performance, many manufacturers have been various attempts. For example, they bandaged the valve on the cover of the multi-layered mat, using refractory bricks box, so that the valve separating the outside world. However, the above methods are less likely to be considered satisfactory because each time the valve repair should be apart, build on. The same day, due to valve installation location restrictions, it may not be this way.
At present a more satisfactory way is to use a fire bag, it can be put on within a few minutes, maintenance can easily be opened. Bags of material containing multi-layered ceramic fiber (eramic fiber) or glass fiber (fiberglass) bind tightly tied with nylon and used vinyl coated stainless steel wires are properly tied in the device. In general questions, does not need to change the location of pipelines, installation space is small, through the test in 2000 � flame burning for 30 minutes, the valve is still not damaged, the performance is satisfactory.
2, the executing agency of the fire
As the implementing agency and direct control over the location of the valve, so need careful study. In order to close the valve to maintain a timely manner, and therefore easier to fire occasions are often used in pneumatic diaphragm spring steel (iron) executing agencies, mainly the use of low melting point, this feature patch. Fire, due to the low melting point membrane damage very quickly, so spring movement, so that the valve in the closed position. The use of heat-sensitive fusible plug-type holes to reduce the pressure of pneumatic system, particularly suitable for reciprocating piston-type spring executing agency.
A serious fire can change the characteristics of metal parts, there is cause metal tempering features softened and lost, and some metal actually melted. Spring force of the size and tempering characteristics are directly related to whether the burning of residual spring force sufficient to keep the valve position, the need for implementing agencies to conduct combustion tests can prove.
Right valve, the combustion is often necessary to keep the remainder of spring torque valve closed position, closing the force required to appear much smaller than the original output power of the implementing agencies. In the spherical valve body on the implementation of the remaining spring force is very important. In the same pipeline pressure, balanced than the unbalanced ball valve ball valve spring force required to be smaller, so use fire-prone places, people are willing to use a balanced-type ball valve.
To make operation even after burning of the implementing agencies on the need to protect the springs, to make it from the flame annealing effects. Protection of springs can be used three kinds of methods: thermal insulation material, using sprinklers or fire protection coating. Including the multi-layer insulated the tropics, the use of thermal insulation cover or use fire bag, so that implementing agencies in the running for half an hour after the fire. But this trick and sealing method is more cumbersome and inconvenient, accounting for a large space. In the implementing agencies at the top fitted with sprinklers, which has increased the installation and maintenance costs; and often without water due to fire, nor to the sprinkler water supply. Enforcement bodies may be coated with a epoxy-based (epoxy-based) expansion of thin material, so that normal operation of the executing agency. In a combustion experiment, due to the protection of paint, although the fire temperatures as high as 1400 ~ 1700 �, implementing agencies able to work 42 minutes. Test of the spring-loaded with 1600 pounds of cast iron implementing agencies, about 7 feet long, 12-inch cylinder bore, using nine propane torch to burn spray. Throughout the combustion process in the executive body of the spring back and forth once every minute, after the spring burn to reduce the output torque is only 6%, and was mainly due to decreased precision bearings, the friction caused by the increase. Tests showed that burning flame springs are not subject to the impact of the piston and rod seals also remain, such as old, sealed well. After the completion of the pilot, the executive body immersed in cold water. Simulate the role of high-temperature shell suddenly cold. Tests showed that the executing agency of the housing and internal parts are not due to a sudden cooling by the harmful effects.
Expansion coating is cast with me, like using concrete, as when wiping in the field, we must be careful not to wipe seals live in parts, this would allow maintenance of inconvenience. When the coating when it dries to form a hard, impermeable sealing layer. Jamesbury company also built the main body of the disk board and cabinet, respectively, coated, so that maintenance can be opened to move board. If the executing agency is the aluminum body, that the use of paint is difficult to fire because of the low melting point of aluminum (1033 ~ 1150 �), higher than the melting point of the hydrocarbon mixture flame, parts will be failure, the valve can not be closed.
Finally, we need introduce a link protection method. Reciprocating spring-loaded devices from different manufacturers supply valve, these spring-loaded devices in a "pending attack" position, it can only fire when the firing, firing an automatic when the valve to move to the insurance position. There will be holding components can be used fusible link, connecting rod or electric rod brittle. Electric rod and easy to link the role of melting, as heat can be started. Dangerous moment in the fire, which was immediately smoke servo rod device is disconnected, so that the valve is in the insurance bit.
ball valve Trunnion Mounted Ball Valve Floating Ball Valve Top Entry Ball Valve ball valve V Type Ball Valve
We can offer more Knife Gate Valve Information.If you need us according your spcification to produce the Knife Gate Valve .
Need, please e-mail to valve401@gmail.com
Thursday, September 9, 2010
Pneumatic butterfly valve in the powder system for use
Find out the reasons, the proposed solution: In the PLC program, will extend the vibration motor, as far as possible all the shock out of material after the closure of the valve; to 0:00 Scale alignment, all materials will be out after the show for the zero, this time issued by the PLC signal to close the valve; three eccentric butterfly valve will be replaced by a flexible double-eccentric hard-seal butterfly valve (rubber sealing can also be the center line butterfly valve, taking into account the material in the occasional large particles, rubber seal may be non-durable - if there is no particle of the powder material can be considered soft-sealed butterfly valve), because the three eccentric butterfly valve is a valve seat sealing surface of the ramp, that is, sealing surface, so materials can easily accumulate in the sealing surface can not be quickly discharged, and single or double eccentric butterfly valve eccentric no such defects, even if it is sealed the surface of materials, but also when the valve closure of the scratch-off valve plate, thus ensuring a good seal, and seal durable surface. After such a transformation, this problem never happened.
In such a system, need to take into account other factors, such as: materials should not be allowed to put a small car from above directly into the valve when the valve plate (which will also impact the closure of the valve can not close), and materials also need to hydrostatic pressure does not exceed the design of butterfly valves for pneumatic pressure, and so on.
Control valves and manual valves ordinary difference lies in the fact, you can not put it as an isolated view of the components, but must put it as part of the automatic control system to consider the use of control valves, many of the issues, not Selection and configuration, but because of the user's understanding of control valves, control valves, resulting in inadequate control system and fail to debug with the good. As long as the key to understanding the problem, the correct selection of valves and debugging phase in the system control valve to debug, and will be able to significantly reduce the failure rate, so that long-term stability of automatic control system operation.
We can offer more Knife Gate Valve Information.If you need us according your spcification to produce the Knife Gate Valve .
Need, please e-mail to valve401@gmail.com
In such a system, need to take into account other factors, such as: materials should not be allowed to put a small car from above directly into the valve when the valve plate (which will also impact the closure of the valve can not close), and materials also need to hydrostatic pressure does not exceed the design of butterfly valves for pneumatic pressure, and so on.
Control valves and manual valves ordinary difference lies in the fact, you can not put it as an isolated view of the components, but must put it as part of the automatic control system to consider the use of control valves, many of the issues, not Selection and configuration, but because of the user's understanding of control valves, control valves, resulting in inadequate control system and fail to debug with the good. As long as the key to understanding the problem, the correct selection of valves and debugging phase in the system control valve to debug, and will be able to significantly reduce the failure rate, so that long-term stability of automatic control system operation.
We can offer more Knife Gate Valve Information.If you need us according your spcification to produce the Knife Gate Valve .
Need, please e-mail to valve401@gmail.com
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