Sunday, August 29, 2010

a.Chinese enterprises should act as a valve of the main international markets

There is a developed industrial countries from abroad rather interesting statistics: The value of these countries over the valve compressors, fans and pumps of the total output value of the three, the whole machinery industry output value accounted for about 5%. These countries a more intriguing phenomenon: the international popular in recent years, the market movement of the valve from the valve products in China, more and more the international valve market is not the right words in the hands of Chinese enterprises.

    

     Role is still working

    

     Due to the production of the necessary valves casting, forging, welding, plating, pickling, such as the impact of the environment, greater investment in environmental protection, so in recent years, developed countries will be labor-intensive production of valves, in particular the common valve moving to developing countries, such as China. They are usually to developing countries in line with the standards required by the purchase of valve products, and then sold to developing countries and developed countries. Or a sole proprietorship or in developing countries to do joint ventures, product re-sold. Seeking truth from facts that the transfer of industry in which the developed countries, China's valve business or the many benefits.

    

     There are many companies has been made in ISO9001 quality management system authentication and API certified, some companies also made the European Community CE safety certification. At the same time, many of our valve business is fully capable of producing API standard gate valve, globe valve, check valve, ball valve, butterfly valve and other products, product quality to achieve full ISO5208: 1993 test standards. Valve products in China and exports also increasing year after year. Take over the past few years, the output value of 2001 exports 380 million U.S. dollars, in 2002 the export value of 430 million U.S. dollars in 2004, output value of 656 million U.S. dollars of export, the export situation can be seen very well.

    

     Even more gratifying is that China's valve industry manufacturers have set up factories abroad, such as Suzhou Valve Factory has set up factories in Iran. Manufacturers also have offices in foreign countries, such as Zhejiang Founder valve plant in Singapore, the Netherlands, with offices in Italy, produced almost all of the valves for sale abroad. At present, the valve has been exported to the United States, Canada, Germany, Italy, more than 30 countries and regions, has entered the world valve market, China's export valve valve exporting countries in the world ranked in the first 11 or so.

    

     However, despite the overwhelming outpour of domestic products abroad valves, valves in the international market, Chinese enterprises still do not have the right to speak. Prices are decided by others, the rules say is the people. Developed countries from China to buy a very low valve, and then sold to developing countries, coupled with the price, they bought another benefit. And domestic enterprises can only serve as a working role.

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Experts teach you how to choose the right valve (b)

Butterfly valves are commonly used for clip-on butterfly valve and two Flanged butterfly valve. Clip-on butterfly is double-headed bolts to connect the valve between the two pipe flange, flange type butterfly valve is a valve on the flange, the bolts on both ends of the valve in the pipe flange connection method Lan on.



Ball



Ball is evolved by the stopcock. It has the same 90-degree rotation to action, unlike the faucet body is a sphere, a circular through-hole or channel through its axis. Spherical and the proportion of openings should be such that when the ball 90-degree rotation, in imports and exports should all show spherical, thus cutting off the flow.



Ball only about 90 degrees rotation of the rotating operation and a small torque can be closed tightly. Full equality for the medium of the body cavity to provide a little resistance, through the flow channel. Ball valve is generally believed that the most appropriate use of direct opening and closing, the recent development has been designed as a ball valve so that it flows with the expenditure and control purposes. Ball is in itself the main features of compact structure, easy operation and maintenance, applicable to water, solvents, acid and gas, such as working media in general, but also applicable to the work of the medium conditions, such as oxygen, hydrogen peroxide, methane and ethylene and so on. Ball Valve can be a whole can also be modular.



Selected by the valve to prevent the media back



This type of valve is to allow only 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.



Parameters selected by the media regulator valve



In the production process, in order for the pressure medium, the flow in line with the process parameters such as the requirements of regulating agencies need to regulate the above-mentioned parameters. Regulation of the main working principle of agency, by changing the valve with the valve flap valve and the flow area between valve seat to achieve the purpose of adjusting the above parameters. Such valves are collectively referred to as control valves, which rely on the media into the drive itself is called self-drive-style control valves, such as relief valve, regulator valve and so on, leading up any power-driven (such as electricity, compressed air and fluid dynamics), he referred to as drive control valve, control valve, such as electric, pneumatic and hydraulic control valve, such as regulating 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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Why is the use of 10 valves

In the process of using the valve is not easy in a lot of attention, Ben Wang compiling answers to these questions, for the exchange of technical personnel



1, why is a small two-seater valve opening hours of work likely oscillation?



Pairs of single-core, when the medium is open-type flow, the valve stability; when the medium is a closed-type flow, the valve of the stability of the difference. There are two spool valve seat, the next spool in the flow of closed, open on the spool in the flow, so that a small opening in the work, the flow of closed-type valve spool is easy to cause vibration, which is two-seat valve can not be used for the work of a small opening reason.



2, why double-sealing valve as a shut-off valves can not be used?



Two-seat valve spool force balance the advantages of the structure, allowing large differential pressure, and its obvious drawback is that two sealing surface can not be good contacts at the same time, resulting in large leakage. If it is artificially Mandatory used to cut off occasion, apparently ineffective, even if it made a lot of improvements (such as the double-sealed sleeve valve), is also undesirable.



3, what straight poor performance, aiming to halt the stroke control valve, angle valve, prevent the travel of good performance?



Direct travel is vertical throttle valve spool, while the medium is the level of flow into the outflow valve cavity flow channel bound to turn down Shui Po, so that the valve flow path becomes quite complex (shape such as the inverted "S" type). In this way, there are many dead zone, the precipitation of the medium provides a space for the long run, causing blockage. The direction of travel throttle valve angle is the horizontal direction, the level of flows into the medium, the level of outflow, easy to clean media is not removed, flow path at the same time simple and very little room for medium precipitation, therefore, prevent the valve angle stroke of good performance.



4, why do straight stroke adjustment valve stem smaller?



It involves a simple mechanical principle: sliding friction, rolling friction small. Trip valve stem straight up and down movement, packing slightly pressed a little, it will stem bag tightly, resulting in a larger backlash. To this end, valve stem is designed to be very small, they often fill a small friction coefficient of PTFE packing, in order to reduce hysteresis, but the resulting problem is that stem thin sent, then the easy to bend, filling a shorter life expectancy. To solve this problem, the best way is to turn valve stem with the brigade, namely, the class trip valve angle, and its stem stroke than the straight stem crude 2 ~ 3 times, and the selection of long-lived graphite packing, valve stem stiffness Well, filling long life, but its friction torque is small, a small hysteresis.



5, why cut off the angle valve pressure class travel more?



Angle type valve to cut off travel greater pressure is due to media in the spool or the valve plate force generated by the rotational axis of the torque produced is very small, so it can withstand a greater pressure differential.



6, why the use of desalination water medium rubber lined butterfly valve, lined diaphragm valves and short service life?



Desalination of water medium containing low concentration of acid or alkali, they have a greater corrosive to rubber. Rubber showed expansion of corrosion, aging, low intensity, with the rubber lining of the butterfly valve, diaphragm use the results are poor, its essence is caused by corrosion of rubber impatience. After the rubber lining for Diaphragm Valves to improve corrosion resistance of a good Lining diaphragm valves, diaphragm valves of the diaphragm, but lined up and down then stand up to collapse were broken off, resulting in mechanical damage to valves shorter life expectancy. Now the best way to deal with specific water valve, it can use to 5 ~ 8 years.



7, why use a hard shut-off valve should be closed?



Shut-off valve required leakage as low as possible, soft-sealing valve leakage is the lowest cut off the effect is good, but not wear and poor reliability. From the leakage volume is small, sealed and reliable double standards, not as hard on the soft sealing off sealing off well. As a full-featured ultra-light control valve, sealing the heap are wear-resistant alloy protection, high reliability, leakage rate of 10-7, has been able to meet the shut-off valve requirements.



8, why sleeve valves instead of a single, two-seat valve does not wish fulfilled?



60 years came sleeve valve, 70 years large-scale use at home and abroad, and 80 years the introduction of the sleeve valve petrochemical plant accounted for a larger proportion of that time, many people think that the sleeve valve can replace a single, two-seat valve , to become the second-generation product. By now, is not the case, single-seat valves, seat valves, sleeve valves have been the same use. This is because the sleeve valve is throttling the form of improved stability and maintenance of better than single-seat valve, but it's weight, aiming to halt and leakage targets with single-seat valve in line, how can it replace the single-seat valve it? So, the only shared use.



9, Why is selection is more important than the calculation?



Calculation and selection of comparison, the selection should be much more important, much more complex. Because the calculation is a simple formula, which itself does not lie in the accuracy of the formula, but rather by the given parameters are correct. Selection related to the contents of the large, slightly careless, would lead to selection of properly, not only causes human, material and financial resources to waste, and use the result was unsatisfactory, and has brought a number of user issues, such as reliability, life, running quality.



10, why in the pneumatic valve in the piston executing agencies will be more and more?



For the pneumatic valve, the piston executing agencies may make full use of gas supply pressure, the executing agency of the size smaller than the membrane, a greater thrust piston in the O-ring and reliable than the film, so its use will Yuelai more. 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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Procurement valve when the technical requirements of the valve

In choosing the most appropriate for your use of the valve should be careful. In order to avoid ambiguity, it should be for each one to make an accurate valve requirements. In the inquiry or order when the valve should be required to make full and proper instructions.

    Select Valve Path

    Must be determined and valves connected to the pipe nominal diameter.

    Valve Material

    In determining the correct valve material, it should consider the following factors:

      * Valve fluid medium to be controlled by

* Fluid temperature range

* Valves to be to withstand the pressure range

* May affect the valves work in climatic conditions

* Valve to be experienced, possible abnormal pressure or stress

* Want to meet the safety standards or procedures pipe

    Valve Type

    What are the functions of the control valve? Each valve structures are used to playing a certain function. Do not expect the entire pipeline of a valve capable of all functions within the system.

    Pressure - Temperature Rating

    In order to meet actual needs, please pay special attention to the required pressure valves - temperature rating. Should pay special attention to sealing materials and liner materials, which to a certain extent determines the valve's pressure - temperature rating. According to the actual need to specify the sealing materials and deposition materials to meet or better than the actual demand.

    Valves and connections

    Pipeline system integrity, the future routine maintenance, corrosion factors, field assembly, weight and safety, etc. are all factors that determine the mode of valves and piping connections should be taken into account.

    Operation mode or operating methods

    According to valve type, size, pressure, temperature, environmental factors such as installation select the appropriate operating mode or method of operation.

    Valve Order

    When ordering valv
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Wednesday, August 25, 2010

Valve procurement, the technical requirements of the valve

In choosing the most appropriate use of the valve you should be careful. In order to avoid ambiguity, it should be made for each valve provides precise. In the inquiry or order should be required to make the valve comprehensive, appropriate description.

     Select Valve Path

     Must be determined with the valve connected to the nominal pipe diameter.

     Valve material

     In determining the correct valve material should consider the following factors:

       Valve to control the fluid medium

Fluid temperature range

Valve to withstand the pressure range

Valve may affect the climatic conditions of work

Valve to withstand the might of the abnormal pressure or stress

To meet the safety standards or pipeline order

     Valve Type

     Control valve for that? The structure of each valve are used to play a function. Do not count on a valve of the pipeline system can play all function.

     Pressure - temperature rating

     In order to meet the actual needs, please pay special attention to the required pressure valves - the temperature rating. To pay particular attention to sealing materials and liner materials to a certain extent, determines the pressure of the valve - the temperature rating. According to the actual needs of the designated materials and sediments sealing materials to meet or better than the actual demand.

     Valves and connections

     The integrity of the piping system, the future day-to-day maintenance, corrosion factors, field assembly, weight and safety factors are determined that the valve and pipe connections should be taken into account.

     Operation mode or method of operation

     According to valve type, size and pressure, temperature, environmental factors such as the installation select the appropriate operating mode or method of operation.

     The valve ordering

     Valve when ordering, please provide the following information to avoid repeated and unnecessary delays in the purchase to ensure that the valve is required by its own valve.

     1. Valve Path.

     2. The pressure of the interface materials: casting materials and components.

     3. Valve types: ball valve,globe valve, check valve, butterfly valve, ball valve, and so on.

     4. Terminal connections, if the connection for the welding, but also to provide connection pipe wall thickness; if the connection is a flange, it must provide the polishing surface or flange degrees.

     5. Any standard configuration different materials: sealing materials, sediment material, bolt material, and so on.

     6. Any Annex: Anti-acid protective layer, locking devices, chain operation, and so on.

     7. Manual or power implementing agencies: Please include the required technical details.

     8. To order your convenience, make sure that model specifications.

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Plug-in electro-hydraulic control valve in the hydraulic system of support (a)

Plug-in discussed in the electro-hydraulic control valve stent application in the hydraulic system and prospects based on proposed design, analysis of the works. Cartridge Valves that through-flow capacity, fast response, the use of electro-hydraulic pilot control, particularly suited to the condition of the stent, in line with the trend of technological development, it is worth promoting.



Keywords: Plug-in Valve; electro-hydraulic control; Stent; hydraulic system



1, based on analysis of application



Moving low-speed has become a fully mechanized production constraints an important factor. To speed up the frame-shift speed, the stent system used hydraulic cartridge valve. Directional Valve Cartridge-type solenoid valve is used as a pilot valve, main valve (poppet valve) to the pilot control, control theory equivalent to electro-hydraulic control valve, but the cartridge valve flow passage of the capacity (up to more than 10000L/min) large , fast response, work to highlight the advantages of reliability is unparalleled tubular valve to make it more suitable to support the electro-hydraulic control systems without the need to develop the pilot to control the use of electromagnetic flow dedicated large main valve, which meet the application requirements, but also improve work performance, improve the general level of a fundamental solution to the tube valve defects inherent problems.



In addition, the design of stent cartridge valve hydraulic system also has the following advantages:



(1) Cartridge Valve is suitable for the advantages of working conditions stent. Hydraulic support of the working condition is characterized by: low-medium viscosity, high pressure, flow, and working environment, medium pollution. Plug-in Valve's strengths can be brought into full play.



(2) in line with the transmission fluid technology trends. In order to reduce cost and eliminate environmental pollution, fluid transmission technology is the direction toward the development of the use of pure water medium. Hydraulic support is closer to nature with the water of the high-water-based emulsion as a working medium, the technology is likely to be the beneficiaries of the fruits of development, is moving to work in water media. Due to the low viscosity of water, the requirements of the sealing valve, and to improve system efficiency. Cartridge Valves using cone sealed with good sealing performance, but also for work in water media, should be preferred as a water valve stent types.



(3) anti-pollution and strong, reliable work. Support work in the mining face, a high degree of media contamination, so that spool of serious wear and tear, shortening the life of the valve, which also led to a variety of stent failure, so that the work of lower reliability, increased maintenance time and reduce the work surface productivity. Cartridge Valves and valve spool of the suites with no stringent requirements, wear light, easy to plug, it does not produce the phenomenon of hydraulic card tight in the medium than the dirty stent when the hydraulic system can guarantee normal work reliably.



(4) to meet the special needs of working condition. Such as strong pressure for the cycle of hard and difficult to support the roof caving stent, in the roof to a sudden pressure, the column control valves under the cavity of the safety valve, to pass a lot of transient traffic, the general safety of the pass far from being able to meet the flow capacity through-flow requirements, and therefore designed a large flow of inflatable safety valve, to adjust to this condition. However, the structure of the valve complex and difficult to manufacture, assembly requirements, the working poor reliability, it is difficult to meet the application requirements. Moreover, the column should be installed under the general safety valve cavity to adapt to the needs of the normal working condition, which will undoubtedly increase the number of components and manufacturing costs. The use of plug-mounted relief valve, you can easily solve this problem, but also will simplify the system.



2, the working principle analysis



Based on the above analysis using the Plug-in design of electro-hydraulic control valve stent design of the hydraulic system and programs, and its working principle as shown in Figure 1. The system consists of two parts, electrical and hydraulic components, stored procedures support the action of micro-computer (the central and stent controller) issued a directive, the cartridge-type valve in the direction of the electromagnetic valve before the pilot action, the two-gate cone valve, connect or disconnect jack post or over the circuit so that actions in accordance with a certain order. Jack post or over working conditions and displacement by the pressure sensor feedback to the controller, the controller feedback signal in accordance with the decision of an action.



Due to the central controller and controller support the Internet, it is from the central controller or the controller of the aircraft can face any of a stent to control the action.



The role of the central controller to control and coordination of the controller for each stent. In addition, the program can automatically, modify system parameters, monitoring of working conditions for each stent, such as display speed shearer. It can support all actions of a separate control, sequence control, group control and automatic control. 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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Piston valve principle and introduced the R & D

 VAG piston valve principle and introduced the R & D

And only used for pipes of different cut of the butterfly valve and gate valve, piston valve is adjustable to meet the requirements of a variety of special valves. The adjustment function is similar to the piston through a cylinder-shaped cavity in the valve for axial movement achieved.

     Features

     Design features: plants adapted to different occasions, the fluid conditioning requirements; the best anti-cavitation characteristics; high flow capacity; sealing systems and long service life, metal and flexible materials, double-sealed, closed tight, using pressure balance-driven, so the operation needs power of small according to the different requirements of operating conditions can be replaced by exports of parts of stainless steel piston sliding does not produce a reliable guide tilt or run sluggish can be installed on any location.

     How it works: enter the water from the axial arc-shaped shell, no matter what position the piston in the valve cavity flow cross-section regardless of any position are ring out at the exit axis of contraction, so as to avoid the idea that may arise due to cavitation the valve body and pipe damage, while regulating characteristics are linear, its standard size: DN150 to DN1200.

     Features: Fluid control valves are used; in the open circular cross-section under the conditions of the circulation; linear regulator; integration of body; according to different working conditions to adopt a different control unit; export of components from the vertical movement of the crank-driven organizations to control ; standard configuration with a position indicator of the gear box; flange standards with EN1092, PN10/16 standards; body length of follow the EN558-1, the basic sequence of 15 (DIN3202, F4) standard.

     Applications

     Diversion: VAG piston valve can be used as discharge valves shall be equipped with ring shorting devices, also can be used as explosion-proof pipe valve.

     Storage: VAGLH type or E-type piston valve can be used as liquid level or pressure regulating valve.

     Water: VAGLH type or S-shaped piston valve can be used as flow control valve, E-type or the net LH release type can be used as irrigation pipe valve or valves.

     Water / Sewage Treatment: VAG E-type piston valve can be used to protect valves to start pumps, or with a specific regulation of export of components, can also be used water treatment plant flow control valve. VAG E-type piston valve can also be used as a sewage treatment plant gas regulating valve.

     Water: According to the working conditions of export of different parts, as pressure / flow control valve, for example, pressure balance pipe network. ball valve Trunnion Mounted Ball Valve Floating Ball Valve Top Entry Ball Valve ball valve
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Valve logo

 Universal valve must be used and can choose to use logo items, as shown in the table. For manual valves, if the hand wheel size is large enough, then there should be instructions on the hand wheel valve closed arrows or additional "open" "close" message.

    Universal Valve Logo Program (GB12220): Nominal diameter (DN); Nominal pressure (PN); compression component materials, code-named; manufacturer name or trademark; medium flow arrows; seal ring (pad) Code; limit temperature (℃ ); thread code; limit pressure; production plant number; standard number; smelting furnace number; inner parts material code; station number; lining material code; quality and testing mark; inspectors imprinting; manufacture, month and year; flow characteristics.

    A specific hallmark of common valve as follows:

    (1) For DN ≥ 50mm valves should be marked on the body; For DN ≤ 50mm valve, marking on the body or the nameplate on the requirements by the product designer.

    (2) when certain types of valve standards, there are provisions must be used when a sign, they should be separately marked on valve body and flange.

    (3) If the standards of various types of valves are not special provisions. When necessary, can be marked on body or plate.

    For the valve, the valve on the signs in addition to the provisions of the table, there should be: a: ex-factory date; b: for medium; c: outlet pressure.

    Steam Traps table below provides the sign may be located in the body can also be marked on the plate. Steam Traps logo (GB12249) must use the logo:

    Product model; DN; PN; manufacturer names and trademarks; medium flow direction; maximum working pressure; maximum operating temperature.

    Either choose to use the logo: body material; the maximum allowable pressure; the maximum allowable temperature; the maximum drain temperature; serial number, date.

    Safety Valve logo (GB12241)

    Valve on the signs: nominal diameter DN; body material; manufacturer name or trademark; when the import and export connections part of the size or the pressure levels were equal, there should be arrows indicate the flow direction of medium

    Signs on the signs: valve design allows maximum working temperature (℃); the entire set pressure (MPa); based on the standard factory No. benchmark model; nominal discharge coefficient or for a rated displacement of the base medium; flow area (mm2 ); opening height (mm) over the pressure the percentage of

ball valve Trunnion Mounted Ball Valve Floating Ball Valve Top Entry Ball Valve ball valve V Type Ball Valve
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Monday, August 23, 2010

Analysis of common failures of boiler safety valve (b)

The elimination of the adjustment bolt is tight, and when the bear bolted diagonal according to the tight manner, preferably while tight space around edge measurement will bolt fixed tight to tight, the combination of surface and throughout the gap unanimously. Second, combination valve gasket surface profile does not meet the required standards. For example, the radial profile gasket marks a slight groove, parallel difference, too sharp or too tooth defects such as the slope will cause seal failure. Surface so that the combination valve leakage. In the overhaul of spare parts when a good quality of the tooth using standard gasket on the occurrence of this phenomenon can be avoided. Third, body surface flatness combined with poor or live in hard-pad caused by impurities in seal failure. Combination of body surface as a result of the flatness combined with poor body surface caused by leakage, the method is to eliminate valve combined with the disintegration of re-grinding surface until it meets the quality standards. Pad as a result of impurities in seal failure caused by living in the valve assembly when the combination of carefully cleaning the surface to avoid falling into the hands of impurities.



2.3, impulse action先自safety valve safety valve does not move



This phenomenon is commonly referred to as the main security door and refuse to move. Refusing to move the main security door in the operation of the boiler to run against is very large, the equipment is a major risk, seriously affecting the safe operation of equipment, once in the operation of the pressure vessel and the medium pressure pipeline in more than ratings, the main security gate do not move, so that equipment can easily run overpressure damage caused by equipment and major incident.



The analysis of the main security gate before the reasons for refusing to move, first of all analyze the main security door action principle. Figure 1, when the pressure within the pressure vessel up to the whole impulse pressure safety valve, safety valve impulse moves through the medium from the container into the main pipeline valve piston room, the Pistons will have a small indoor expansion step-down, if the piston chamber pressure at this time for the P1, the piston area of expenditure Shs, this time on the role of f1 in the piston is:



F1 = P1 × Shs ... ... ... ... ... ... ... ... (1)



?? If this time the pressure containers for medium pressure P2, the area of spool Sfx, is now a medium on the spool upward force f2 as follows:



F2 = P2 × Shx ?..............( 2)



Normally a safety valve spool piston diameter than the diameter, so-style (1) and type (2) Shs> Sfx? P1 ≈ P2



If spring up through the stem of the valve core is set to f3 and the rally will be moving parts and friction between the fixed parts (mainly the piston and the friction between the piston chamber) as fm, while the main security door a prerequisite for action: only the role of the force in the piston slightly larger than the role of f1 in the spool so that the upward spring force f2 and upward through the stem of the spool tension f3 and moving parts and friction between the fixed parts (mainly the piston and friction between the piston chamber) fm and time of that: f1> f2 + f3 + fm am to start the main security gate.



Through practice, the main security door and refused to move the following three main factors:



First, there are moving parts valve resistance phenomenon card. This may be due to improper assembly, or mixed with dirt and impurities parts corrosion; piston chamber poor surface finish, surface damage, there are groove marks, such as hardware defects. This will enable the moving parts and fixed parts fm between the friction increases, other conditions remain unchanged in case of f1 <f2 + f3 + fm therefore refused to move the main security gate.



For example, in 2001, before the 3rd overheated furnace overhaul the main security door steelyard weight test run, the occurrence of the main security door refused to move. When the dissolution of maintenance inspection found that the Pistons have a lot of rust indoor dirt and impurities, the Pistons could not campaign in the interior piston, resulting in the main security door refused to move. Maintenance on the piston, and piston ring expansion room to deal with the rust, groove marks on the piston chamber defects, such as grinding, assembly room wall before the Pistons lead powder coated evenly and strictly carried out in sequence on the valve assembly. When the boiler pressure test on the pulse tube for washing, and then the main security gate valve connected with the impulse, overhaul furnace after the point when the safety re-run all the normal tests steelyard weight. 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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Blank valve selection principle

 There are commonly used in rough machining castings, forgings, profiles and welding parts. Different types and rough rough accuracy, roughness and hardness of the machining process has a direct impact.

     Select Valve blank the following factors should be considered:

     ⑴ parts materials and the organization of materials and performance requirements.

     The design of parts and materials required to be provided, largely determines the type of blank. For example, the part of cast iron material for casting methods must be used to make rough. For the steel parts, should be considered in the selection of rough materials, the mechanical performance requirements. For example, the manufacture of high-pressure valve components in general should try to use forged or welded parts, to ensure the material has good mechanical properties.

     ⑵ parts of the structure shape and form factor.

     Parts of the structure and shape are important factors affecting choice of blank, for example, complex shape of the body structure should try to use casting. A large body size can choose sand casting; small size while using investment casting.

     ⑶ the size of the production program.

     The greater part of the production program, using high-precision and high efficiency as possible economic effects of blank manufacturing methods.

     ⑷ blank manufacturing conditions.

     Should be based on site conditions and technological level of equipment to select the blank, and to consider prospects for the development of the rough phase the use of advanced manufacturing methods. 

  ball valve Trunnion Mounted Ball Valve Floating Ball Valve Top Entry Ball Valve ball valve
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Flanged butterfly valve features guanlong Profile


  Flange butterfly valve is the introduction of the United States HATMAN self-sealing valve design company design philosophy, self-developed successfully developed, in which the valve flap and valve shaft connected with the U.S. Patent and sales structure designed to pull back. The main features of this valve is sealed reliable, bi-directional sealing, and the connection close, not loose, so that the valve using the long-term. Its characteristics are as follows:

    1, two-way seal

    Usually the traditional butterfly, because of its structural reasons, in the opposite direction (the direction is not conducive to sealing) working pressure, not well sealed, the relevant state standards are not mandatory two-way sealed, but the valve can be designed ensure that PN operating conditions to achieve bi-directional sealing effect. This is due to:

    1. Using self-sealing design concept

    Flap valve seals rubber embedded directly to the serrated valve flap, without the use of pressure ring or a bolt is fixed, thus avoiding the traditional bolt-type seal platen seals Shouli Bu result of both, so that bolts loss, and premature failure of seals . Ring in the opposite direction under the effect of working pressure, resulting in a self-sealing edge, so that sealing specific pressure increased, the valve seat ring pressed, the greater the pressure in the opposite direction, then the self-sealing force is also larger, so that with the valve seat ring are linked closely together to achieve bi-directional sealing effect.

    2. Valve flap rigidity is good, not easily deformed

    The butterfly valve DN300 flap over dual-plate truss flow-through structure, flow resistance is small, rigidity is good, working pressure in the opposite direction, not easy to deformation, so that does not ring with the valve seat valve deformation from the best seal-point, thus ensuring the seal of the sealing effect.

    3. Rubber O-ring and long life

    ⑴ As a result of the design concept of self-sealing, rubber rings and stainless steel valve seat of interference between the relatively small amount is to maintain the initial seal, it seals the needs of specific pressure along with the system pressure increases.

    ⑵ In addition, serrated leaves within a groove for the rubber elasticity of the so-called concessions to "breathe" slot, so that when the rubber under pressure in a certain stretch of space, so that long-term fatigue on the Bu Zhiyu produce flexible, so seal significant increase in life expectancy than traditional patterns.

    Second, the patent sales structure designed to pull back

    Usually butterfly valve in the use of the process, due to the traditional pin connected to pin from the valve shaft through the heart of not only reduces the strength of the valve shaft, but also in the process of long-term use and the resulting gap between the valve shaft, which, when the switch valve an impact load, the load is far greater than under normal circumstances, compression stress and shear stress generated by the load, often occurs in the course of marketing a serious deformation or fracture, so that the valve closure of lax or ineffective, and greatly reduces valve life. Production of valves, using the U.S. design patent pull back the structure to replace the pin axis and the pin connection between the flap valve structure, sales do not pull back through the valve shaft of the center, not only will not weaken the strength of the shaft, but also with the valve shaft of the Laminated surface greatly increased, by tightening pull back pin nut, so that pulling back pin and valve shaft preload that arise between joint surface, so that valve flap valve shaft tightly together without gaps, in the opening and closing the valve without will be an impact load, so that a smooth rotation flap valve, so as to achieve a reliable seal.

    Third, the unique design of the bottom of the axial adjustment of locking device

    In the DN300 butterfly valves in the above specifications, taking into account the reliability of sealing butterfly plate weight, in the manufacture of precision through the axial position of adjustment and fixed, so that valve flap in the seat in the best position on the state seal. In the long-term use that may arise in the course of the valve flap to sag, further adjustments can be easily locked up long-term use of zero leakage.

    4, seal replacement easy

    When the seals need to be replaced when the valve flap need not removed, simply fully open the valve and then remove the key devices operation will be transferred to shut down after the operation device and the main valve remains key connection, and then turn towards the direction of continues to turn the handwheel until the O-ring seals in the valve body can replace the face side of ring.

    To achieve the above-mentioned advantages of the unique needs of sophisticated process to ensure that it takes a higher cost, but the valve to ensure the quality of customer satisfaction, enhance the technical level of similar butterfly valves, our products continue to insist on the use of advanced technology, exquisite craft to create, and strive to pass with a soft seal butterfly valve products can reach international advanced level.



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Saturday, August 21, 2010

What are the advantages and disadvantages of automatic control valves?


The operational efficiency and save energy consumption, the use of automatic control valve is an indispensable part of traditional industry used manual valves, pneumatic valve, the installation cost and efficiency are not and electric valve.



The industry concerned that the valves in industrial processes, the most used to control the road and flow of various fluids such as water, oil, chemical liquids, etc. based on the parameters are temperature, pressure and flow. The plant control valves are commonly used in valves, pneumatic-type fixed temperature valve, solenoid valve fixed temperature system, proportional control valve fixed temperature system, several types of temperature control valve. In the selection of various types of automatic valves, they should consider the type of heat engine, the required accuracy, the quality control valves, pressure drop, flow and structure, failure rate, credit and after-sales service manufacturers and other factors, in order to achieve economic and practical purposes.



On the product itself, due to electric valve with easy assembly, the failure rate is low, as well as meet the industry's automation needs of the merit of being the industry more cost-effective choice. Since the use of conventional pneumatic valve, will inevitably have a piping, solenoid valve and the compressor in order to match, while the electric valve is a motor-driven, easy to install save trouble, and the installation of electric valve-controlled line with the original plant can be saved other costs. In addition, motor-driven opening and closing means relatively smooth, non-transient momentum is too large disadvantage of the failure rate can be greatly reduced.



Many people think that electric valve expensive, the use of high cost, it is not true, if the overall terms, the traditional valve to add a number of accessories and pipe installation, the price is not dominant, but have to bear more of the maintenance costs.



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Dump Truck valve technology standards (d)

8.1.2 Where one of the following conditions must be Type tests:



a) reversing the trial (including the old products to plants);



b) When the valve design, process or material changes in performance affect the time;



c) the valve has been stereotyped in the factory test and the pattern of previous test results to occur when the deviation can not be allowed;



d) production batches should be conducted every three years, reversing a pattern of test.



Test and test items:



A) commissioning tests;



B) the scope of the entire flow pressure loss test;



C) with the leak test;



D) Pressure test;



E) durability testing.



8.1.3 Type tests as the number of samples 3 (pieces), in which the entire project to do a test, only the performance of the remaining tests have failed item, the item should be based on the number of double re, such as The project is still not up to standard, the samples for type test failed.



Factory 8.2 trial



Products should be made at the factory before the factory tests, in order to pass inspection by the factory.



Test and test items:



A) commissioning tests;



B) the rated flow capacity of pressure loss under the test;



C) with the leak test;



D) Pressure test.



8.3 to determine the criteria



8.3.1 sub-valve factory pilot project will test and two types of sampling, sampling methods carried out by GB/T2828.



8.3.2 orders for the factory units have the right to pilot projects and requirements for review of the valve, according to review the sampling method for GB/T2828.



8.3.3 reversing special order request, their experimental conditions and rules from the design, manufacture and development of demand-side units.



9 signs, packaging, transportation, storage



9.1 marks



Valve products have a nameplate, and indicate the following:



A) Product name, type and graphic symbols;



B) the main technical parameters of products;



C) the name of manufacturer;



D) ex-factory date.



9.2 Packaging



Reversing the packing material should be moisture-proof ability. The box should be solid and reliable, and its outer wall should be clearly marked neatly marked with the following:



A) Product name, model and quantity;



B) the total mass, kg; net mass, kg;



c) receiving unit name, address and points of departure and arrival;



D) the date of packing. 

  

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What are the common material body? Respectively, are how to handle it?

Body a wide range of materials suitable for a variety of working conditions.



Body has the following nine kinds of commonly used materials:



1. Gray cast iron, suitable for operating temperature between -15 ~ +200 ℃, nominal pressure PN ≤ 1.6MPa low-pressure valves.



2. Black heart malleable cast iron, suitable for operating temperature between -15 ~ +250 ℃, nominal pressure PN ≤ 2.5MPa of the low-pressure valves.



3. Ductile iron, suitable for operating temperature between -30 ~ +350 ℃, nominal pressure PN ≤ 4.0MPa of the low-pressure valves.



4. Carbon steel (WCA, WCB, WCC), applicable to operating temperature between -29 ~ +425 ℃, the high-pressure valves, which 16Mn, 30Mn working temperature between -40 ~ +450 ℃, often instead of ASTMA105.



5. Low carbon steel (LCB), applicable to operating temperature -46 ~ +345 ℃ low temperature valve between the valve.



6. Alloy Steel (WC6, WC9), applicable to operating temperature -29 ~ +595 ℃ The non-corrosive media, high temperature and pressure valves; WC5, WC12 apply to operating temperature between -29 ~ +650 ℃ The corrosive medium high temperature and pressure valve.



7. Austenitic stainless steel, suitable for working temperature -196 ~ +600 ℃ valve between the corrosive medium.



8. Monel alloy, mainly applied to hydrogen fluoride medium valve.



9. Copper alloy, mainly used in the working temperature of -273 ~ +200 ℃ with the valve between the oxygen pipe. Wear-resistant electrode



Body listed above is commonly used materials in the major categories, specific for each type of material, there are many different grades and different grades also apply to the different pressure levels. So, the choice of the valve body materials, should be based on different uses and different pressure levels to determine the conditions suitable for the needs of body material.



In addition, the valve body materials are titanium alloy (titanium valves), aluminum alloy (aluminum valves); plastics (plastic valves); ceramics (ceramic valves) and others.



Body Blank heat treatment process according to different materials are as follows:



1. Gray cast iron heat treatment.



In order to achieve different purposes, gray cast iron in the foundry after the heat treatment can be different. Valve production of pairs of gray cast iron valve body parts such as are often used in the foundry after the heat treatment process are: the elimination of thermal aging thermal stress and the elimination of free cementite of high-temperature annealing. Thermal aging is a necessary process. High-temperature annealing only in the casting due to the chemical composition and casting speed control cooling properly, resulting in the organization after casting primary cementite exists only use it to replace the thermal aging.



2. Carbon steel heat treatment.



Steel casting in the foundry after the casting has a large residual stress, and sometimes coarse steel pieces of the organization, and even overheating organization. These all affect the size of the stability of steel parts to reduce the mechanical properties of steel and is not conducive to the conduct of cutting. In order to eliminate thermal stress, refine, and improve the mechanical properties and improve the machining, etc., the production of the carbon steel valve body and other parts are often used in the foundry after the annealing, or normalizing and tempering.



3. Austenitic stainless steel acid-heat treatment.



Austenitic stainless steel acid-resistant major flaws are easy to produce intergranular corrosion, and can be taken to impose a certain degree of heat treatment of steel of preventive measures. Valve production of acid on the austenitic type stainless steel valve and other parts are often used in heat treatment process are: solid solution treatment (quenching), stability, processing and cryogenic treatment.



4. Martensite-type heat-resistant steel heat treatment.



Martensitic-type heat-resistant steel in the foundry should be promptly after the annealing, prevent the generation of cracks, and the holding time should be sufficient annealing (usually 4 to 8 hours). Martensitic-type heat-resistant steel annealing which aims to eliminate stress, to recrystallization, grain refinement, reduce stiffness, improve cutting performance and to organize and prepare for the final heat treatment.



Martensitic-type heat-resistant steel end-use of normalizing + tempering heat treatment.



5. High-quality carbon steel heat treatment.



High-quality carbon steel heat-treatment to 35 forged steel valve, for example, 35 # steel body to conduct normalizing after forging, heat treatment and its ultimate technical documents according to the provisions of the valve manufacturing execution, generally for quenching and tempering treatment. ball valve Trunnion Mounted Ball Valve Floating Ball Valve Top Entry Ball Valve ball valve V Type Ball Valve
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Thursday, August 19, 2010

How to make better in the radiator valves play a role in (b)

Before the factory such products to its strict temperature devices and testing of the experiment at the same time, as a result of metal in frequent after stretching and bending characteristics, such as the existence of changes in fatigue fracture, and ductile metal with, so will such a sense of temperature devices affect the life and accuracy. Some manufacturers to produce products such valves, rarely seen their foreign products.



2, valve body



Valve body is generally made of copper, nickel appearance, in accordance with its inlet and outlet temperature controller is installed between the valve core can be divided into the following point of view.



1) Direct-type valve body: and the water inlet valve angle of 180 ° 2)-angle valve Valve: inlet and outlet valve angle of 90 ° 3) three-dimensional valve body (three-dimensional valve): inlet valve, the valve core into the water and 90 ° angle, similar to X, Y, Z coordinates.



4) The special combination of valve body: for some new radiator (such as the bathroom radiator, etc.) and some connections (for example, by leaps and bounds in single-tube), many manufacturers also introduced a number of special modular valve Body. Not in this list.



3, valve Kvs value and Kv value



Products abroad, the water regulating valve resistance value tends to be used Kv said a lot of Chinese-made products are used valve Kv value labeled water resistance characteristics. Kv value is defined as the regulating valve in the valve before the valve after the pressure drop for 1bar through the flow control valve. Kvs value of said regulating valve opening when the largest value of Kv. The following formula can be converted to Kv value commonly used in local resistance coefficient ξ value.



4, the radiator valve radiator system in a variety of the proper use of



4.1, in the majority of our old radiator heating system is used in vertical up and down through the single-tube or twin-tube system.



1) in the vertical single-pipe system, radiator water, the former group all through the next set of radiators, each radiator and is located in a different floor, radiator thermostatic valve can not be installed. Could be considered for such a system of vertical single-pipe system, so that the radiator can be installed in each valve or adjust the properties of a good manual control valve.



2) in the vertical double-pipe system, due to the existence of vertical imbalance in the system can be installed with pre-setting function of the radiator valves. That is, the so-called pre-set features on the valve body with a pre-set the initial resistance of the device, the device will be available through the initial resistance valve settings, different floors of the initial resistance between the different settings can be certain solve the problem of vertical imbalance. However, this method to be used in practice do the following; designers to do more detailed hydraulic calculation; installation, construction has to carefully than on the provision of water supply factory flow chart resistance to valve transfer to accurately pre-set position; in the water running, can be carried out in accordance with the specific circumstances of individual adjustments. Two-pipe system as a result of the high-resistance valve (after the details of the text will do), at the same time pre-set regulator further reduces the valve opening, so a higher quality of the heating requirements, otherwise easily cause obstruction.



4.2, in recent years, household heat metering technology in increasing the level of indoor household heating-loop system for the majority of civil and industrial construction gained widespread application, this system is also designed with a maximum of arrangement of indoor heating. Heating radiator layout is divided into levels: the level of single-type pipe (not allowed in the standard, non-recommended), the level of single-tube by leaps and bounds, on a twin-tube fraction, fraction of a twin-tube, radiation dual - tube a few major categories.



1) the level of single-pipe type: horizontal single-pipe system with the earlier single-pipe vertical systems are similar, the heating water flows through a heat sink before flowing into the next group after the full radiators Therefore, should not be installed on each radiator valves or manual valves. 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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Electro-hydraulic servo valve failure causes and solutions

  Wet alarm valve is automatic sprinkler system, central nervous system, the normal operation of whether or not it directly affects the normal operation of the whole system, so the wet alarm valve routine maintenance is very important.

     1, an alarm should be turned half check whether it is normal, check valve when the play opened, alarm valves due to water pressure valve automatically opens, water flows into the retarder by 20-30 seconds after the alarm bells sound. If the alarm does not send sound, should check the alarm piping, excluding its scale, sediment and dirt, so that water flow to prevent the alarm failure. If the alarm check cocks closed, the alarm is still sound, it should check whether the verification cock tightly closed, in the alarm valve annular tank whether the accumulation of obstacles, alarm valve under the rubber flap is aging or wrinkles. These failures should be immediately removed.

     2, semi-annual checkup flow pressure, check valve open play, alarm bells sound, this time, pressure gauge shows the pressure values should be decreased, if the drop is more significant, should check whether the plug or gate valve to open Maximum; If the pressure gauge shows the pressure drops more obvious, and the alarm did not the police, should check the wet alarm valve flap valve starts are normal.

     3, check valve flap on the rubber gasket sealing surface, clear rubber sealing pad attached to the dirt and foreign matter; if worn or damaged should be replaced promptly.

     4, should be checked once a year seal and valve seat ring slots, removing dirt or foreign body; if damaged, should be replaced spare parts.

     5, according to the water quality of water from fire service, regular open sewage outfall on the filter, clean dirt.

     6, daily attention to the fire pond water level and water pressure and the corresponding valve in which the state is in line with regulatory requirements.

     7 False Alarm handling:

     Found that false alarm, they can look at the entire pipe network is leaking, check the delay overflow drainage holes are blocked or impeded. Open the bleed valve may be emptying test or inspection within the system water supply pipe network is blocked.

     Check wet alarm valve valve seat valve components and the question of whether Mifengbuyan, so that large amounts of water into the retarder.

     Check the sprinkler pipe network Whether the cause of the accident led to the release mechanism to start.

     Identify the reasons for false alarms, should a timely manner in order to ensure that the system at all times in good standby. 

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Tuesday, August 17, 2010

Valve 50 billion yuan accounting for one-fifth of the market abroad

  

In accordance with China's "Eleventh Five-Year" development plan, China's valve industry, especially focusing on the two major water supply and construction of the valve market enterprises in energy-saving, environmental protection, security, sustainable development strategy as compared with the international advanced enterprises is still There are gaps. Mainly reflected in: a smaller scale Chinese enterprises, low skill level, the brand is still relatively weak competitiveness. These issues be resolved in time if we do not greatly affect China's valve industry, the level of the overall package, but also restricting the valve industry in China grow up healthily. Reorganization is to integrate the valve industry in China must go through the process. Only through large-scale and large-scale integration of high-quality assets, the rapid formation of a strong group effect, in order for brands to become the leading China valve market to ensure that users in China, the urgent need for high-end products.



After 20 years of development, China's enterprises of various size valves about 6,000 more than the number of firms in the world, of which more than 5 million yuan annual output value of 900. Product situation, China's valve industry is now capable of producing more than a dozen major categories of products, such as gate valve, globe valve, ball valve, butterfly valve, safety valve, check valve, throttle valve, plug valves, pressure relief valve , valve, steam trap, such as emergency shut-off valve.



National Development and Reform Commission released in 2008 Notice No. 11, 351 new standard for the industry in July 1, 2008 opening of the machinery industry-standard 253, involving 30 of the valve industry. In support of national policy in 2009 under ,2008-valve industry will maintain a good momentum of development. Forecast 2010 total sales of valves 6.736 billion yuan, total exports of valves for 2.009 billion U.S. dollars, total imports valve 3.632 billion U.S. dollars.

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Smoke damper valve applications in engineering quality requirements (a)

1, fire damper, exhaust valves are mainly used for



And other types of high-level modern buildings are equipped with ventilation, air-conditioning and smoke control system, in the event of fire, these systems will become the flame of the pipe, flue gas channel spread. In order to prevent the fire spread through the air duct, in the "architectural design code for fire protection" GBJ16-87 and the "Code for Fire Protection Design of Tall Buildings" GB50045-95 are clearly defined in the fire dampers, smoke



Requirements valve settings.



Fire dampers in ventilation and air conditioning system to send back to the wind pipe on the road, was open in peacetime, when the event fires, pipeline gas temperature reaches 70 ℃ when the closure of its own, and in a certain period of time to meet the fire-resistant stability and fire resistance the integrity of the requirements of the role played Fire smoke. Exhaust valve in the exhaust system or exhaust pipe of the suction fan at the entrance, was closed in peacetime, when the fire broke out when, through the fire alarm signal to open the valve manually or automatically, in accordance with the smoke extraction system, when the pipeline within the flue gas temperature reaches 280 ℃ automatically shut down, and within a certain period of time to meet the integrity of fire-resistant stability and fire resistance requirements, since the role of smoke Fire.



2, damper, exhaust valve in the ventilation and air conditioning, smoke control system to the important role of



Fire damper fire damper including gravity, fire control valve, fire air, pneumatic damper, smoke damper, electronic control products such as smoke damper; smoke damper valve, including smoke, I smoke Plate ( roof used), vertical mouth with smoke and other products. Fire damper, exhaust valve is ventilation, air-conditioning and smoke control system an important component in the system, the important role played by the following three aspects:



2.1, the role of smoke Fire



In the air supply system, air blower must be sent through the trunk to the branch pipe of the distribution; in the smoke extraction system, the flue gas from the branch to the trunk pipe, the smoke into the exhaust fan. When the building when fire broke out in the ventilation and air conditioning systems, in order to prevent the spread of fire through the air supply system, when the air supply system in the gas temperature reaches 70 ℃, the damper on the fuse body movements, the rapid clearance valves are valves to cut off the flue gas duct and the fire spread along the access road. Similarly, in the smoke extraction system, the case of fire, smoke valve open, the smoke, in order to cut off high-temperature flue gas flow in the exhaust pipe to prevent the fire from spreading to another fire district, when the flue gas exhaust temperature reached 280 ℃, the smoke fire dampers, smoke mouth movements on the fuse, must be self-closing valves to prevent the smoke. This shows that the fire damper, exhaust valve to achieve the General Qualcomm, which were broken off Fire the role of smoke. 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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Line of butterfly valves in high-performance anti-corrosion series, how to apply?

1, using two parts-type stem without pin connection, simple structure, compact, maintenance, demolition is very convenient (available on-site removable); disc plate has an automatic right in the function (from top to bottom, left and right), disc plate and the valve seat to achieve a small surplus over with the amount.



2, tongue-slot seat, ensuring valve, valve seat, the precise connection between the disc plate, while you can easily replace the seat.



3, using the world's advanced spherical seal pair, seal more reliable. Because it is spherical sealing valve in the open and close smoothly when excessive, so to reduce friction and lower torque, you can use low-power drives, thus reducing the user cost. While increasing the service life of the valve seat (which is common centerline valve 3-4 times).



4, valve seat flange sealing surface with large broad-brimmed, large arc structure, so that the valve can meet the set of well-formed or welded flange connection request, suitable for use with any standard flange connection.



5, stem axial positioning device, using two pads plus a card off the ring and spring ring structure methods. This could effectively prevent the stem has no intention of being demolished, at the same time can also carry a certain degree of axial force to prevent the stem weight passed to the butterfly plate.



6, stem from a two-way sealing ring role, namely, to prevent foreign material intrusion, while preventing outflow of medium.



7, sleeve not only stem from the role of supporting the same time, open and close torque can be reduced. There are two kinds of sleeve to choose from, namely: lubricating bronze, PTFE.



8, due to its alternative common valve seat of the back, increasing the overall strength of the valve so as to achieve common center line butterfly valve can not be achieved nominal pressure of 20 kg

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Sunday, August 15, 2010

Pneumatic control valve vibration causes and treatment

  Vibration control valve generally divided into two states, one is the control valve as a whole vibration, that is the entire control valve in the pipe or the base frequency vibration. The other is the regulating valve spool of the vibration, which from the stem can be seen moving up and down frequently, the following two kinds of vibration in this analysis of the causes and treatment measures are as follows.

     Vibration of a control valve as a whole

     The control valve causes vibration in the pipe is as follows: pipe or severe vibration base could easily cause a vibration of the valve; In addition, with the frequency, that is, when the external frequency and the system natural frequency equal to or close to the energy when the forced vibration reaches its maximum, resulting in resonance. These two factors may sometimes mutual influence will lead to vibration of the more intense vibration, so that pipe beating, accessories or component loosening, and issued clatter clatter of noise, will result in a serious stem fracture, seat off, causing the system not work . Based on this situation, respond to vibration caused by the pipeline and base reinforcement, which also help to eliminate outside frequency interference.

     2 spool vibration

     Sometimes, the flow rate of a sharp increase in measured media, so that differential pressure regulating valve before and after the drastic changes in the stiffness when over valve, the valve on the deterioration of the stability, which could cause severe oscillations throughout the regulating valve. However, this oscillation is not necessarily a small valve opening caused. This vibration usually associated with ear-piercing screams. Poor stability control valve, if there is internal or external unbalanced force and interference than the stiffness of valve and control valve themselves do not have the ability to eliminate this interference, we generated oscillation. There needs to increase the stiffness of control valve, such as the 20 ~ 100KPa the spring, or to increase the stability of its work, there is a certain advantage.

     Regulating valve installation location should be away from the vibration source, such as the inevitable, should take preventive measures.

     This vibration of the control valve, before we can achieve the resonance case, with the valve is basically outside the given signal can be carried out adjustments. Because of the given signal the relative displacement of the spool is not due to the vibration of the control valve to change or change little, the reason is that they are a whole.

     Regulating valve at both ends of the cut-off valve to open or Meng Meng off, make a sharp movement of the wave-measuring medium produced a strong red reflection wave, reflected wave shock regulator valve core. When the diaphragm is greater than downward pressure on the spool when the spool will move up to generate vibration, especially in the small-signal conditions, due to preload a smaller, easier to spool vibration generated.

     Control valve opening is too small, so that before and after the differential pressure regulating valve is too large to make the mouth at the cutting velocity increases, pressure decreases rapidly. If the pressure drops at this time to the liquid at that temperature the saturation vapor pressure, the liquid can produce gasification, the formation of flash, generate bubbles, burst bubbles formed when powerful pressure and shock waves to generate steam hammer, the pressure is generally up to tens of MPa. Pneumatic hammer shock spool to spool the formation of cell surface and to spool vibration Zhuang Ma.

     The reasons for the general spool vibration is as follows: regulator output signal instability. Fluctuated rapidly changing at this time, such as valve positioner sensitivity is too high, then the regulator output of small change or drift, it will immediately convert the output signal a great location. Causing valve oscillation. The friction control valve is too small, such as the filler valve installed too little, or did not tighten the gland, external input signals are small changes or drift will be immediately passed to the spool to spool vibration, and issued giggle beep. On the contrary, such as the friction control valve too, such as the filler loading too much, then screw too tight gland or stuffing aging, dry, then the action can not be in the small signal, the signal is large one produced by the action and then generate overshoot phenomenon, would produce hysteresis control valve oscillation, vibration curve was similar to a square wave. In such cases, it should reduce the corresponding part of the damping control valve to solve, such as the replacement of packing and so on. Fluctuations in gas supply to output fluctuations in positioning, or moving parts locator rust, not flexible, so that does not correspond to the input and output signals, resulting in oscillations by leaps and bounds. You should open the gas supply valve cleaning locator to the moving parts coated with lubricating oil, in order to eliminate friction.

     As the control valve itself the result of unbalanced force, so that adjustment spool regular oscillation. 12:00 spring-tight edge top is too small, the ability to resist outside interference is small, in the case of a small external signal, easy to make spool vibrate.

     To sum up, according to practical experience, the author diagnosed, in general, the spool oscillation of the measured effects of media control valve is always greater than the whole the impact of vibration on the measured medium, and the spool oscillation causes and preventive measures the total oscillation than the entire control valve complex causes and preventive measures. Practice can also be seen, these two causes of vibration and can not share it clear, sometimes mixed intertwined. 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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Smart gate valve actuator system hardware component


Intelligent controller based intelligent, high reliability, strong anti-interference ability, low costs, in principle, control, 8-bit microprocessor core MC68HC908SR12 (SR12), the main motor control circuit using power electronics technology.







SR12 has the speed, functionality and price, strong and low. Its maximum operating frequency of up to 8MHz, 512 bytes of on-chip RAM, 12K bytes of on-chip FLASH memory, 14-channel 10-bit A / D, and SCI, I2C, SPI and other communication interface [1,4].







System Application SR12 within the A / D input signal and valve position to control signal acquisition, the use of PWM output through the filtered position signal, using I2C bus to communicate with external memory AT24C08 memory settings, using SCI interface through the MAX485 and the Upper machine data exchange, made full use of the chip's internal resources and save costs.







2.1 The signal input part of the







The use of SR12 internal A / D conversion, the analog input signal and valve position feedback of the analog signal to quantify. With REF02 as A / D reference voltage, the temperature drift coefficient of 3PPM / ℃.







2.2 The signal output section







SR12 has 3-channel 8-bit high speed PWM, each channel has a separate counter, selectable PWM input clock to generate a variety of PWM frequency, and automatic phase control. To use one all the way as the analog output PWM signal, the other two-way as motor control signals. Choose the same time, I / O port PTB6 as a relay switch output of the control signal.







2.3 Input-output isolation







System when used in the industrial scene, involving a variety of instruments, sensors and implementing agencies, for various reasons due to the introduction of signal interference, as well as the dangers of strong voltage signal. To ensure the security of the system to ensure testing accuracy and reliability of operation, using optocoupler LOC210 isolation of input and output signals.







2.4 Communication part of the







In order to complete the industrial field remote control and networking needs, the system supports RS485 communication. Level conversion chip MAX485. Practical work, they can carry out long-distance communication with the host computer to carry out operation mode to set and monitor operation status.







2.5 motor drive part of the







The use of electric motor-driven electronic switch TRIAC BTA16. Bidirectional thyristor with switching speed, long life, no spark and pull characteristics of arc phenomena [2], to ensure the implementing agencies under the conditions at high temperature long-term reliable operation, while helping the motor protection. Between the main circuit and the CPU use of opto MOC302X drive, as shown in Figure 3, the figure for the electrical load ZL.







In the design, MOC3020 diode forward current of 15mA, MOC3021, and MOC3023, respectively 8mA and 3mA, it can be MC68HC908SR12 the I / O port with sink directly drive. RC absorbed in practical work, the actual parameters need to loop motor parameters (ZL) to determine the difference.







Note that, MOC302X the voltage is 400V, if the motor need to work at 380V or under the motor back EMF relatively large, we should use MOC308X series.







3 Software Design







Controller's software mainly by the main program, man-machine interface, procedures and automated debugging, fault handling, A / D conversion and data processing, manual operation composed of fault handling routines. The main program flow shown in Figure 4.







In the implementation process, to judge the fault condition and found that failure, the immediate alarm display, while the output volume of a group of relay switch signal to the user, and cut off electrical power supply.







System uses four key methods used to realize the complex system of control and parameter settings. Four keys defined, respectively F (Function), U (Up), D (Dowm), S (Shift). F for the function keys, click here to enter setting menu, repeatedly press F key to exit the menu after. U, D keys to increase and decrease respectively represent the current values or preferences, in the manual operation on behalf of up or down commands. S as a toggle key, you can change the current input focus, with the U, D keys, can easily achieve any number of input.







In the motor control algorithms using PID regulation, to avoid overshoot, oscillation occurs, while an optional direct proportional control and proportional control mode + stepper control, so that the system can be applied in different types of motors.







System software design allows the valve can be adjusted at both ends of position, as long as the adjustments made after a good limit switch auto-tuning (F, S key while pressing the 10s) can greatly facilitate the users. System also provides RS485 communication protocol, the user can programmatically control valve through the host computer so that networked communications and computer-controlled valve more convenient.







4 Conclusion







Of the system all the major functional blocks concentrated in the single-chip microprocessor, reducing the system cost, improved reliability, reduced size, can be directly installed in the actuator without the need for change within the body of the original machinery, which not only facilitates the the existing implementing agencies of production, but also conducive to the transformation of the existing old equipment. At the same time, the system's hardware design fully into account the industrial surroundings of the scene and adopt a comprehensive anti-jamming measures and fault protection measures so that the system can be applied in industrial surroundings of the scene.







The system has been actually put into production, at present in a variety of industrial environments work well.



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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