U.S. industrial valve seal ball hard to solve the transport problem

U.S. industrial valve seal ball hard to solve the transport problem

U.S. Industrial Valve Group's natural gas pipeline for the current technology and the development of a comprehensive analysis of a number of drawbacks to push a Waston pipeline valves - WastonB70 series of hard seal ball valve. The product is a comprehensive solution to the traditional products in the gas transportation deficiencies.



U.S. industrial gas pipeline valve Group Technical Summary:



1. Because of pipeline transportation of natural gas desulfurization ago contains a lot of hydrogen sulfide (which is a highly toxic and corrosive gases). Process even after the desulfurization of natural gas, there are still remnants of hydrogen sulphide. Therefore, selection must be selected pipeline valve corrosion resistance to sulfur material.



2. An average city gas pipeline are hundreds of kilometers or more, only regular patrols, inspection, and sometimes complicated pipeline through the region, media leaks could result in serious fire incidents. In particular, away from the city closer to the pipeline, to prevent the leakage of the valve is particularly important.



3. Pipeline, once operational, are not allowed to stop within a few years running, does not allow a short break, and no overhaul period. Series in the pipeline on the pipeline valve failure, lead to disastrous consequences. Therefore, the vulnerability of pieces of pipeline valves requires long life.



4. Control personnel in general or in the station control room, it requires a reliable control valve performance, and require a self-protection and explosion-proof valve measures. In particular, long to open the valve, requiring mutations in the situation among the cutting done and accurate. Therefore, a reliable control performance be the focus.

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Elastic properties of metallic hard sealing butterfly valve Profile

Flexible metal seal butterfly valve is a state-level key new products, high-performance flexible metal seal butterfly valve uses a double eccentric, and a special sealing structure oblique elliptical cone. To solve the traditional eccentric butterfly valve in the headstock 0 ° ~ 10 ° the moment still in the sealing surface of the drawbacks of friction sliding contact, the realization of butterflies in the opening moments plate sealing surface that is separated from the closure of the effect of contact that is sealed to extend the service life of sealing performance The purpose of the best.

     Uses:

     For sulfuric acid in the gas pipeline industry: the import and export steel blower, blower relay entrance, electricity and Unicom　valve series, S02 Blower main entrances converter regulation, import and export, such as preheater and the closure of the air-conditioning use.

     System for sulfur-burning sulfuric acid burn in the sulfur, the transformation of drying and absorption section, the sulfur-burning sulfuric acid plant with the preferred brand valves, the majority of users were considered to be: a good sealing performance, running light, the Deputy corrosion, high temperature, easy to operate, flexible, safe and reliable use of the butterfly valve has been a great deal to promote the use of.

     Also widely used: chemical, petrochemical, metallurgy, medicine, food and other industries in the SO2, steam, air, gas, ammonia, CO2 gas, oil, water, salt, alkali, water, nitric acid, hydrochloric acid, sulfuric acid, phosphorus acid medium, such as regulation and control on the road as the use of closure devices.

     Structural characteristics:

     ① three unique eccentric design to the sealing surface so that no friction between the drive to extend the service life of the valve.

     ② torque generated by the flexible seal.

     ③ clever wedge design of the valve clearance has become more tight self-sealing function of sealing surface between the compensatory, zero leakage.

     ④ small size, light weight, compact operation, easy to install.

     ⑤ configured according to user requirements pneumatic, electric devices, to meet the needs of the remote control and program-controlled.

     ⑥ replacement parts could be applied to a variety of media materials, and conducted anti-corrosion lining (lining F46, GXPP, PO, etc.).

     ⑦ continuous structural diversity: for folders, flange, butt welding.

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Plastic sub-catchment and the valve device works in the application of warm (a)

Sub-catchment of plastic raw materials for the overall product requirements, design requirements, performance requirements, matching plastic valves and plastic filter test method requirements and the use of pressure and temperature, etc. that can find sub-catchment of the plastic device and sealed with a plastic valve test, torque test and fatigue test of basic quality control requirements, in order to facilitate sub-catchment of plastic valves and plastic device to determine the quality of selection and procurement.



Keywords: plastic valve plastic sub-catchment seal test device fatigue test



Warming in the rapid development of industry, the low-temperature floor radiation heating of the pipeline and the overall quality of support system also appears to require more and more important. With the low-temperature floor heating system in radiation applications, the proportion of construction work and continuous improvement, a variety of systems sub-catchment of the copper, and stainless steel sub-catchment, and plastic sub-catchment, and temperature control devices, a variety of materials valves, filters, and tube connector into engineering applications one after another, if not give the user control and bring the entire industry is adversely affected. The following sub-catchment devices on plastic and plastic valves to briefly outline the technical requirements.



Sub-catchment as a result of plastic valves and plastic device has a light weight, corrosion-resistant, non-absorption scale, can be integrated with the plastic pipe connected to a long life, production and installation of high efficiency not stolen after the loss of the advantages of plastic sub-catchment devices with plastic valves in the low-temperature floor radiation heating system, its advantages in the use of other materials or products are not mentioned in the same breath. At present, the domestic sub-catchment of the plastic device with the plastic valve in the production and application, there is no corresponding national or industry standards of their control, resulting in uneven product quality. With the rising price of copper, plastic and plastic sub-catchment devices such as valves and the rise of products has gradually expanded its market share. In order to protect the interests of consumers and to warm the healthy development of the industry, China's sub-catchment devices plastic valves and plastic is to declare national standards-making process.



The international community for the plastic to warm sub-catchment's varieties are mainly polypropylene, glass fiber reinforced material such as nylon 66 products. There are no plastic water's international standards, but the sub-catchment of the plastic unit supporting the valve need to be consistent with international standards.



International main types of plastic valves are ball valves, butterfly valve, check valve, valve, gate valve and shut-off valves, etc. There are two main structural forms pass, links and multi-valve, the main raw materials are ABS, PVC -U, PVC-C, PB, PE, PP and PVDF, etc.. Used to warm the main varieties of plastic ball valve and plastic valve.



Valve in the plastic products to international standards, the first valve is used in the production of raw materials to carry out the requirements of the manufacturer of its raw materials must be consistent with the plastic pipe product standard curve of creep damage; At the same time, the sealed plastic valve testing, valve body test, the overall long-term performance of the valve test, fatigue test and operation of the torque requirements are carried out, given the design life of plastic valves for 25 years.



Plastic filter materials to meet the same pieces of plastic pipe to meet the technical requirements and sub-catchment of the use of system requirements.



1. Plastic sub-catchment, and plastic valves and plastic filter products, the technical requirements



Raw material requirements of 1.1



Products in line with the selection of materials should be selected GB/T18252-2000 "plastic pipe systems extrapolation of thermoplastic pipe hydrostatic strength of long-term determination" requirement. 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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Dynamic balance valves in HVAC engineering (c)

3, air-conditioning design should be based on return water temperature difference between summer and winter water for a reasonable set of dynamic balance valve



Control air-conditioning systems in the four balance valve with both winter and summer is to meet the different requirements of water, when the winter and summer air-conditioning heating sections, cold water temperature is not at the same time, significant differences in water flow, water in the two control systems should be in accordance with Winter and Summer in different settings Valve flow requirements: a way to set up Dynamic Variable Valve flow, summer and winter season when the converter valves.



Method II, set up two balance valve, valve 1 by the choice of the winter flow valves, valve 2 by the summer and winter, the largest difference between the choice of water, valves, valve 1 in winter, summer two valves, two valves to achieve air-conditioning the four control functions. Method III-controlled device with a dynamic balance valve flows through the computer. Otherwise, air-conditioning in summer due to water flow in winter is different and simple to set up in the air conditioning fixed end of the dynamic flow balance valve is not possible to meet two of the water balance of the season.



6, dynamic balance valve design example works



1, project



Located in Beijing's bustling King Street down well commercial market, is from Beijing Dong'an Group and Sun Hung Kai Real Estate Development Co., Ltd. joint venture to build the project, covers an area of about 21400m2. Large-scale construction projects, construction plane is divided into A, B, C, D in four areas, including A, B, area market segments; D areas for the dynamic part of the move-back city. Floor, six on the ground, on the podium for the tenth floor office.



Market旧西危total load of frozen room 10450RT (about 36750KW).



Air-conditioning chilled water from the ground floor of three rooms at ground floor two primers. In order to reduce the non-commercial area. Water system for the next time for the next two-pipe system, different programs. The second floor from the ground to the 20 air-conditioned well water pipes.



Water fan-coil system in accordance with the load characteristics of the construction is divided into areas within and outside the two loops area. For chilled water within the district, outside the district heating water in winter. According to the indoor climate and in line with the situation, through the building automation system in the two-story underground shaft electric switch controlled by the extracellular region of cold water dual, hot water switch.



2, air-conditioning program designed to balance valve



For chilled and frozen pump unit is, in order to avoid a variety of factors contained in the occurrence of partial load, in the freezer and set the water flow on the secondary pump outlet Valve installed.



Market as a result of the construction plane large, and require the owners and architects "golden land" effective area of the high rate of business, premises and equipment, tube wells, therefore the small size and its location is also a negative, so that the vertical reach of 108m, the horizontal cross-270m the pipeline system, pipeline system, the resistance balance and debugging is very difficult. In order to solve the water system "long pipeline is difficult to balance" the difficulties of the design process to develop a balanced program of two sets.



Program One: a multi-polar set general installation of water pipes Crosshole Valve



① is in charge of line with the 20 wells installed heating pipes Valve



② installed in the shaft export balance valve



③ in each box to install air-conditioning Valve



④ tenants in each of the balance valve installed on outlet



Option II: Using Dynamic Balance Valve



① The fan coil unit is installed on the end of balance valve



② air-conditioned box at the end device is installed on balance valve



Tested compared to the final adoption of the balance valve is



① me the end of the installation of air conditioning and automatic control valves Valve



② retail and office space within two or three fan-coil combination of a balance valve and control valve, fan coil units in each office outside the area occupied and controlled a balance valve valve



3, the application of the Aggregate Balance Valve



① long pipeline system different way to install multi-level balance valve price is higher than the general level of dynamic balance valve terminal equipment.



② the end of the device in the dynamic balance valve installation, maintenance, when the scope of the impact of small, air-conditioning equipment and start and stop the tenants affected.



Dynamic balance valve ③ own filters, to avoid the water system on line in the dirt-controlled valve damage.



④ Because of the dynamic pressure balance valve for a certain period within the scope of error of only ± 5%, the more equipment on or off the flow of the other equipment is almost no impact to ensure that the end of the stability of water flow devices. 

  

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Concerned about the performance of the four solenoid valves

 1. Security:

     1. Corrosive media: should use plastic Wang solenoid valve and all stainless steel; for the strong corrosive medium must be selected isolated diaphragm. Cases of CD-F. Z3CF. Neutral medium, it should use copper alloy for the valve shell materials, electromagnetic valve, otherwise the shell valves are often chip off rust, especially the movements infrequent occasions. Ammonia with the valve can not use copper.

     2. Explosive environments: explosion-proof grade products must be selected accordingly, open-air installation or dust should be used more occasions, waterproof, dust-proof varieties.

     3. Solenoid valve Nominal pressure shall not exceed the maximum working pressure of pipe.

2. Applicability:

     1. Dielectric properties

     1.1 The quality of gas, liquid or mixed state were selected to different kinds of electromagnetic valve cases ZQDF for air, ZQDF-Y for liquid, ZQDF-2 (or -3) for the steam, otherwise easily cause malfunction. ZDF Series multi-function solenoid valve can be them altogether in the air. Liquids. The best set, went out the state media, install the user no longer modal.

     1.2 Medium temperature products with different specifications, otherwise the coil will be burnt, seals aging, seriously affect the life of life.

     1.3 medium viscosity, usually in the 50cSt below. If it exceeds this value, diameter greater than 15mm Series multi-function solenoid valve with ZDF to make a special order. Diameter of less than 15mm solenoid valve provides a high viscosity.

     1.4 Cleanliness is not high when the media should be equipped with the electromagnetic valve before the filter backflushing valve, low pressure moving fashion can choose straight diaphragm solenoid valve for example, CD-P.

     1.5 If the directional flow of media, and are not allowed back ZDF-N and ZQDF-N need to use a single two-way flow, please make a special request.

     1.6 Medium temperature should be chosen within the allowable range solenoid valve.

     2, pipeline parameters

     2.1 According to media flow requirements and pipe connection valve openings and model selection. For example, for a pipeline to the two channels to switch, the small diameter of the election CA5 and Z3F, medium or Chase Drive Please select ZDF-Z1 / 2. Another example is control of convergence of the two pipelines, please select ZDF-Z2 / 1 and so on.

     2.2 In accordance with the value of the selected flow rate and valve Kv DN, but also optional with the pipe diameter. Please note that some manufacturers are not marked with the Kv value, often less than the interface valve hole size diameter, must not covet low price and makes a botch.

     2.3 Working pressure minimum working pressure at 0,04 Mpa above is the choice of an indirect Pilot; minimum working pressure close to or less than zero must be selected direct-acting type or sub-step direct type.

     3, environmental conditions

     3.1 environment, the maximum and minimum temperature should be chosen within the allowable range, if the need for ultra-poor special order made.

     3.2 environment, relative humidity is high and there are water droplets and rain and so on, to be elected water solenoid valve

     3.3 environment, often have vibration, bumps and shocks should be elected special varieties such as occasion, such as marine solenoid valve.

     3.4 in a corrosive or explosive environments should be given priority in the use of security requirements under the optional anti-hair loss

     3.5 environmental space if limited, please use multi-function solenoid valve, because eliminating the need for a bypass, and three manual valves and easy online maintenance.

     4, power supply conditions

     4.1 According to power supply types, were selected to AC and DC solenoid valves. Generally speaking, convenient access to AC power.

     4.2 Voltage specification with the best preference AC220V, DC24V.

     4.3 AC power supply voltage fluctuations are usually chosen +% 10% -15%, DC to allow ±% 10 or so, should the ultra-poor, regulators should take measures or make special order requests.

     4.4 The choice should be based on rated power capacity and consumption of power. VA should be noted that the value of the exchange-start high, inadequate capacity should be preferred in the indirect-guided electromagnetic valve.

     5, the control accuracy

     5.1 Common solenoid valve is only opened, closed two locations in the control of high precision and parameters for a smooth when you use a number of solenoid valves; Z3CF three normal open solenoid valve, with Enlight, fully open and close the three kinds of traffic; ZDF -Z1 / 1 combination of multi-function solenoid valve has a fully open, wide open, small open, open all four kinds of traffic.

     5.2 Action Time: refers to connect or disconnect the electrical signal to the main valve movement completion time, and only the company's patented multi-function solenoid valve can adjust the opening and closing time was not only to meet the control accuracy requirements, but also to prevent water hammer damage.

     5.3 leakage leakage given the sample values for common economic level, if too high, please make a special order.

Third, reliability:

     1, working life, this is not included in the pilot project factory belonging to type pilot projects. Formal to be elected to ensure quality, brand-name manufacturers.

     2, the working standard: sub-system of long-term, repeated short-term work system and the three kinds of short-term work system. For a long time only a short-term closure of the valve opening of the case, are advised to use normal open solenoid valve. Short-term work system used in large quantities when they can be used as a special order to reduce power consumption.

     3, the working frequency: Action frequency of requests is high, the structure should be preferred direct drive type solenoid valve, the power to listen to optimize the exchange.

     4, operating reliability strictly speaking to the pilot solenoid valve has not yet formally included in our professional standards, to ensure the quality of the brand-name manufacturers should be regular elections. Some occasions the number of actions are not many, but very high reliability requirements, such as fire, emergency protection, must not be taken lightly. Particularly important, should be used in conjunction to take two pairs of insurance.

4, economy:

     No economy is on the money, energy and even a waste of life, it is one of the choice of scale, but it must be in a safe, suitable and reliable based on the economy, the economy of not only the product price, but also to give priority to its function and quality of as well as the installation and maintenance, and other accessories required for the cost, more importantly, a solenoid valve-controlled systems throughout the entire production line automatic control system, as well as the share of the cost of very little, if just for the sake of small cheap and the wrong group is selected as early as damage huge.

     In short, the economy not just price, but rather a comprehensive cost of the product cost performance price ratio. 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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Anti-corrosion metal valves and synthetic materials, the application of valves

 Valve corrosion, is usually understood as the valve metal material in the chemical or electrochemical environment under the action of the damage suffered. As the "corrosion" phenomenon seen in the metal spontaneous interaction with the surrounding environment were, therefore, how the metal with the surrounding environment isolated or more of the use of non-metallic composite materials, then become common concern.

     As we all know, metal corrosion damage on the role of the valve duration, reliability and service life have a considerable impact. The role of mechanical and corrosion factors on the role of the metal substantially increased the total contact surface wear. Valve in the operation, the friction surface of the total amount of wear and tear. Valve in the operation, the friction surface due to the same time, the mechanical role and Metals and the Environment to conduct chemical or electrochemical interaction of wear and damage results. Right valve, its climatic conditions, the complex pipeline of work; oil, gas and reservoir water medium, hydrogen sulfide, carbon dioxide and some organic acids appear to increase the destructive power of the metal surface, which quickly lose their ability to work.

     Due to chemical corrosion of metals depends on the temperature, the friction parts of the mechanical load, lubricating materials contained in the sulfide and acid stability and media exposure duration and metals on the nitridation process of a catalyst, corrosion erosion of material elements of the metal conversion speed and so on. Therefore, the metal valve corrosion method (or measures) and synthetic materials, the application of the valve will become the subject of study, one of valve industry.

     A metal valve preservation, understood as the metal coated valve to protect against corrosion on the conditions of protective layer (such as paints, pigments, lubricating materials, etc.), so that the valve either in the manufacturing, storage, transport or in the whole process of its use are not subject to corrosion.

     The method of corrosion of metal valve determined by the needs of the term of protection, transportation and storage conditions, the valve construction features and materials, of course, to adapt to consider lifting the economic effects of corrosion.

     Corrosion of metal valves and parts are mainly four kinds of ways:

     1, the volatile corrosion inhibitor into the vapor in the atmosphere (using the resistance of paper parcel, blowing air through the product chamber suppression, etc.).

     2, was inhibited using water and alcohol solution.

     3, the anti-corrosion (Protection) Apply thin layer materials, the surface of the valve and its components.

     4, will be resistance-based polymer thin film, or apply on the surface of the valve and its components.

     (Note: At present, the valve manufacturer, widely used in lubricating materials, and water resistance to corrosion of solvent flow.)

     Second, the application of the valve material

     Synthetic material valve, and in many corrosive conditions in both superior to metal valves, first and foremost anti-corrosion, followed by net weight, as its strength, depends on the shape of the reinforced fiber, arrangement and quantity. (Generally, the greater the percentage of fibers, synthetic materials, the greater the intensity.) In the valve applications, the fiber content of the basic range of the weight of 30% -40%, while its chemical stability, mainly by filling in the final product ontological characteristics of fiber resin sealed the decision. Valve in the synthetic material, its solid polymer body may be either thermoplastic (such as PVC-PVDF, PPS-polyphenylene sulfide, etc.) can also be a thermosetting resin (eg polyester, vinyl and epoxy its resin, etc.). Thermosetting resin in the IL-temperature state to maintain its strength is better than the performance of thermoplastic (ie, thermosetting resins have higher heat distortion temperature). (Note: the use of working conditions, the thermal properties of synthetic materials measurement known as the heat distortion temperature.)

     At present, the most commonly used chemical process valves for the vinyl epoxy resin composite materials (thermal plastic material), its enhanced fiber chopped glass fiber (1 / 4 inch long) and chopped graphite fiber (1 / 4 inch long).

From the surface analysis, glass and graphite composite materials with metal enhanced compared to the lower tensile strength, therefore, synthetic materials, a large part of the valve by the stress of a thick cross-section should be accompanied with metal stiffener in order to achieve the same performance.

Synthetic material of the valve due to corrosion resistance, high strength and light weight, making it in a number of metal or glass fiber reinforced plastic piping systems corrosive conditions, the more economical alternative valve products. In the chemical process conditions, the synthetic materials were excellent prospects for the use of the valve.

      In the valve industry, organic materials and the use of synthetic materials, has not traditionally metal and nonmetal materials, the concept of the valve. Ceramics (could be the valve temperature by 400 ℃ to 1200 ℃ or above), plastic (with rust-corrosion characteristics), synthetic materials (with corrosion resistance, light weight, high strength characteristics), memory alloys (using shape memory alloy or the temperature of the reversible shape memory alloy and high flexibility to manufacture valves), etc.. New materials, is developing a large number of new products with high performance valves. Development of new technologies, so that a variety of engineering materials used in the valve manufacturing industry has become possible. 

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Or into a high-tech investment in the direction of valve

With the continuous development of science and technology, the domestic valve market, but also to the high-tech, high-parameter, strong corrosion-resistant, high-life direction. Valves based on technical analysis at home and abroad and domestic market demand valve and analyzed in recent years the industry of high-tech valves and valve industry development trend and investment direction, are as follows:

 



     1. Oil, natural gas wellhead valve devices

 



     Oil, natural gas wellhead valves are mainly used in the U.S. API6A standard single gate or board, there is no diversion diversion hole or holes parallel steel gate valve, ball valve, angle-type throttle valve (CHOKE VALVE ), pilot-type safety valve and check valve.



     2. Oil, natural gas valve with long-distance pipeline



     Oil, natural gas long-distance pipeline with the main valve in order to comply with U.S. standards API6D single-gate or board, there is no diversion diversion hole or holes parallel Forged Gate Valve; steel or cast steel three-body, coat-style or full welded ball valve fixed ball; oil seal or pressure balanced plug valves; Swing check valve or butterfly valve, pass the ball check valve; pigging valve.



     3. Nuclear power plant valve



     Nuclear power than conventional valve with a large thermal power station valve its technical characteristics and requirements higher. Valves are generally valve, valve, check valve, butterfly valve, safety valve, main steam isolation valve, ball valve, valve, relief valve and control valve.

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History of the development of butterfly

The structural characteristics of butterfly valves for the stem axis, butterfly plate center, the Center in the same body position. Simple structure, convenient manufacture. Rubber lining butterfly valve that is commonly fall into this category. The disadvantage is that as a result of butterfly valve plate and extrusion remains, scratch, and resistance from the large, fast wear and tear. To overcome the squeeze, scratch, to ensure the sealing performance, the use of seat basically rubber or elastic material such as PTFE, but also result in the use of restrictions by the temperature, which is why people traditionally do not believe that high temperature valves reasons.      Second, a single eccentric butterfly valve      To resolve the concentric butterfly valve butterfly valve seat plate and the problem of extrusion, the resulting single eccentric butterfly valve, and its structure characterized by a departure from the stem axis center butterfly plate, so that the bottom plate would no longer be a butterfly rotary heart, scattered, reducing the butterfly valve seat on the board over the bottom and squeeze. However, due to a single eccentric valve structure in the course of the entire switch butterfly valve seat plate and the scratch is not disappeared, in the application scope and concentric butterfly valve more or less the same, so the use of small.      Third, double eccentric butterfly valve      In a single eccentric butterfly valve forming the basis of further improvement is currently the most widely used double eccentric butterfly valve. Structural characteristics of its stem axis in both panels deviate from the Butterfly Center, the Center has also deviated from the body. So that the effect of double eccentric valve was opened immediately after the butterfly plate from the valve seat to substantially eliminate the butterfly valve plate and the unnecessary over-extrusion, scratch phenomenon, to reduce resistance from the open and reduce the wear and tear, increased life expectancy seat. A significant reduction in the scratch, but also makes double eccentric butterfly valve metal valve seat can also be used to enhance the area of the butterfly valve in the high-temperature applications. However, because of its location is an enclosed sealed structure principle, that is, butterfly valve seat plate and the sealing surface for line contact plate squeeze through the butterfly valve seat caused by the effect of elastic deformation generated seal, it demanding the closure of the location (especially metal seat), low pressure, which is why people traditionally believe that intolerance of high pressure valves, a large quantity of the reasons for the leakage.

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the development of foreign pipeline ball valve

Pipeline ball valve for half a century after the development of design in the structure of the formation of two schools. One company in the United States on behalf of Cameron, the use of all-welded structure of spherical body. Fall into this genre of BORSIG companies in Germany, Schuck Corporation, the U.S. company Larsen & Toubro, KITZ Corporation of Japan, TIX company, TUBOTA companies, as well as the Ventura Tyazhpromarmatuva Russian companies, in Figure (a) below; another Italian Grove Schools company representatives, the use of split-type tubular structure, and then on this basis to achieve the development of welded tubular body structure, figure (b) below. Fall into this genre of new PIGNONE Italy (Nuovo Pignone), PCC company, PERAR companies, BFE companies, PIBIVIESSE companies, FCT company PBV U.S. companies, the Czech Republic Czechoslovikia company.



 



(A) the United States Cameron Corporation (b) the Japanese company TIX

Figure (a) of the whole pipeline ball valve welding ball valve





(A) the United States PBV company (b) BFE Company

Figure (b) pipeline ball valve cylinder-shaped body



Cameron U.S. technical characteristics of the company's products: All welded ball valve, nylon or PTFE sealing material may be turning the valve seat, stem up and down shaft bearing, import-side sealed the exit pressure cavity to the downstream side discharge automatically. Figure (a) (a) as shown.

Cameron United States in the fifties on the completion of the whole body welding spherical structure, with its high reliability, by half a century of global commercialization of sales, still retains the characteristics of the original structural design and a well-known brands, is widely used in important long-distance pipeline, such as the Alaska oil pipeline.

Grove Italian company to double piston effect, explosion-proof rubber O-rings or PTFE sealing materials, shaft support plate supporting the ball structure, split-type valve, easy maintenance, competitive market position, is widely used in long-distance pipeline station , booster stations. After the development of cylindrical or quasi-cylindrical welded body ball valves in the long-distance pipeline is also used for emergency shut-off valve.

In some cases, the customer needs online maintenance, the use of the pipeline structure to fit the ball valve, Figure (c) below.



Figure (c) pipeline structure to fit the ball valve diagram (d) Japan valves welded spherical TIX

As a result of commercial competition, the promotion of technically merged. Cameron's products Dynaseal 370 is split structure, body welding products with sales support; Grove also introduced a quasi-spherical structure of the whole body welding line is in charge of access to the application. While other companies such as TIX, TITZ while absorbing the merits of two schools, according to the characteristics of their respective manufacturing processes, the introduction of welded ball valve, dual-piston effect, rubber seal material ball valve product line, combines the technical advantages of the genre. Figure (d) below.

 

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Basic knowledge of control valves

1, control valve selection

     A, the importance of control valve selection

     Regulating valve is self-control system, actuators, and its application quality direct response to the quality of the adjustment in the system. As a process control terminal components, the importance in it than in the past has been updated knowledge. Control valve applications, good or bad, in addition to the quality of the product itself, the user is installed correctly, use, maintenance, correct calculations, selection is very important. Selection of calculation errors, causing the system to open stop-open, and some can not even put into use, so for users and system designers should be aware of the importance of valves in the field, control valve selection must be taken seriously enough.

     B, the principle of control valve selection

     1, according to process conditions, selection of suitable structural forms and materials.

     2, according to the technical characteristics of the object, select the control valve flow characteristics.

     3, according to process operating parameters, select the appropriate aperture size control valves.

     4, according to process requirements, select the required assistive devices.

     5, selecting the implementing agency. The response speed of the implementing agencies should be able to meet the technical

     To control the travel time requirements: the selected implementing agency should be able to control valves sounded very full schedule and process on the valve leakage volume level requirements. In some cases, such as the selection of pressure control valves (including the venting valves), pressure should be considered possible and practicable, appropriate amplification, which would require implementing agencies to provide a larger force. Otherwise, it may appear abnormal when the process occurs, the actual differential pressure control valve before and after the larger, will occur o 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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New high-life characteristics of stainless steel butterfly valve

 At present, the butterfly valve is used to achieve piping system as an on-off and flow control components, has been in the petroleum, chemical industry, metallurgy, water, electricity and many other areas to be very widely used. In the known butterfly has been recognized technology, its sealed form of multi-sealed structure, sealing material for rubber, PTFE and so on. As the structural characteristics of the restriction is not suitable for high temperature, high pressure and corrosion resistance, abrasion resistance and other industries.

     Present a more sophisticated three eccentric butterfly valve is metal seal butterfly valve, valve and valve seat as the Siamese components, valve seat sealing surface layer welding temperature, corrosion resistant alloy material. Soft-stacked multi-ring fixed to the valve plate, this butterfly valve in comparison with the traditional high temperature, easy operation, open and close without friction, closed with the transmission of the torque increases to compensate for seal, to improve a butterfly valve sealing performance and durability advantages.

     However, this butterfly is still in the course of the following problems:

     1, due to soft and hard stacked multi-ring fixed to the valve plate, when the valve plate to its normal open state media, the formation of a positive sealing surface erosion, and metal sheets laminated in the soft-sealing tape subject to erosion, the direct impact on seal performance.

     Second, by the structural conditions that limit the structure do not meet the following diameter DN200 valves, because the overall structure of valve plate thick, large flow resistance.

     Third, because the principle of the three eccentric structure, the valve plate sealing surface and the seal between the valve seat is to rely on the torque transmission device so that pressure valve plate to the valve seat. Positive flow state, the media, the higher the pressure squeezed more tightly sealed. When the flow channel upstream medium with medium pressure increases when the valve plate and seat the pressure between the units is less than the medium pressure, the seal started to leak out.

     High-performance 3-way eccentric hard-seal butterfly valve, its characteristics are: described by a soft T-shaped valve seat ring seal ring on both sides of the composition of multi-layer stainless steel sheet. Valve plate and valve seat sealing surface for the oblique cone structure, in the valve plate oblique cone surfacing temperature, corrosion resistant alloy materials; fixed platen in the regulation of rings between the spring and the adjustment bolt assembly with the platen structure. This structure effectively compensate for the tolerance between the sleeve and the valve stem in the medium zone and the elastic deformation under pressure to solve the two-way valve in the transmission medium of exchange that exist in the process of sealing problems. Use of soft T-seals on both sides of the composition of multi-layer stainless steel sheet with a metal seal and soft seal the dual advantages of both the low and high temperature cases, both with zero leakage sealing performance.

     Test proved positive flow state (medium flow direction and the butterfly plate rotation in the same direction), the sealing surface pressure is the transmission of torque and media pressure on the valve plate of the role of the elected. Positive medium pressure increases, valve plate oblique cone surface and the valve seat sealing surface squeezed more tightly, sealing the better. When the counter-current state, the valve plate and valve seat through the seal between the drive torque to the valve seat so that pressure valve plate. With the reverse-media pressure, valve plate and valve seat unit between the positive pressure is less than medium pressure, the adjustment of the spring ring is contained in the subject after the deformation energy stored in compensation valve plate and valve seat sealing surface of the tight the pressure to play the role of automatic compensation. Therefore, this utility model, unlike existing technologies, as the valve plate to install software and hardware multi-ring, but directly installed on the valve body, in the platen, and the middle seat an additional adjustment ring is a very good two-way hard-sealing method . It can replace valve, the cut-off valve and ball valve. 

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The issue of water supply pipe network of valves

Water supply network to send the water from the waterworks distribution to millions of households, so the distribution of water supply networks in cities in every corner, at least hundreds of kilometers of its length, up to thousands of kilometers.

Irreplaceability of water and necessary for people to live, and determined that the water supply network of the importance of safe operation. However, due to various objective and subjective reasons, the pipeline tends to be some failures, pipe network is always to keep upgrading, water users often have a change, so the local control of water above it is difficult to avoid the phenomenon. In order to narrow the scope of water in the pipe network due to the installation of control valves is necessary. Therefore, in a city's water supply network, the number of tens of thousands of valves, there is no regular distribution in the city streets below.

Water supply pipe-line operation of the valve is not frequent, long-term standby, if necessary, should be able to close the valve rapidly, a reliable closure; usually request to open the valve should be in place to reduce the head loss pipe sections, so the valve is a kind of "Yang-bing A Thousand Days, 1:00 troops "of the control equipment; the good rate of valve related to the selection of valves, valve manufacture, pipeline design, the valve assembly, the gate valve and valve management, The main reason of course is the quality of the valve.

Valve in the water supply network in the large number of widely distributed, the role of big. As a result, valve selection, testing, performance and management of many of the issues are worthy of discussion.

First, the selection valve

     There are butterfly valves, gate valve, ball valves and plug valves, such as several in the water supply network in the scope of the use of different. In order to reduce the pipeline depth of soil, the larger diameter pipes generally matching butterfly; little effect on the depth of soil to matching valve; ball valves and plug valves casting and machining difficult, expensive prices, generally applicable to small and medium-caliber pipe. In recent years, due to improvements in casting technology, the use of resin sand casting method can be avoided or reduced machining, thereby reducing the cost, so the ball valve for large diameter pipe is worth exploring the feasibility. As for the size of the line diameter should be considered throughout the division by the specific circumstances.

The main disadvantage is the butterfly butterfly board to occupy a certain cross section, add the head loss; valve no problem, but the large-diameter vertical pipe valve of a high impact on the soil depth of large diameter horizontal valve increased the length of horizontal pipe occupied area, the impact of other arrangements for the pipeline; ball valves and plug valves are maintained single valve, the flow resistance in small, sealed reliable, flexible movements, operation and maintenance of the advantages of convenience. Plug valves also have similar advantages, but not the cross section is circular.

In recent years, many valve manufacturers to develop soft-sealed gate valve, the valve and cut the traditional or parallel plate gate valve双闸compared the following characteristics:

1. Soft sealing valve of the valve body, valve cover the use of precision casting foundry, a molding, it is no longer machining, non-use of sealed铜环, saving non-ferrous metals;

2. Soft sealing gate valve at the bottom of pit-free, non-accumulation of Java objects, the gate valve failure rate is low;

3. Soft rubber lining the valve seal uniform size, strong interchangeability.

So soft sealing gate valve gate valve will be the development direction of the water supply industry is also reluctant to adopt a kind of valve. Soft sealing gate valve, the closure should not have to die, as long as the sealing effect can be achieved, otherwise difficult to open or peeling rubber lining.

Water supply industry is mostly used in soft-sealed butterfly valve butterfly valve, butterfly valve for the apron during the installation process easy to damage the impact of tightness, the introduction of many manufacturers to replace metal seal butterfly valve butterfly valve sealing apron. Metal seal butterfly valve seals due to the flexibility of small, generally eccentric structure, especially the use of three-dimensional structure is more reasonable eccentricity.

Second, the performance and test valve

The specificity of valves require reliable quality and performance. Performance evaluation of valve performance testing and should note the following:

1. Water pressure valve in the workplace under the headstock flexible, lightweight, water pressure in the work of testing using a torque wrench torque to open.

2. Valve tightly closed, in the 1.1-fold under the pressure of work does not meet the criteria for leakage or seepage requirements (metal sealed butterfly valve), which requires both sides of the rotation pressure valves were used to detect, and many sluicegate achieve the same effect. Requirements of various calibres, different types of valve manufacturer shall be qualified and have a detection unit with the life span of the load detection headstock. This testing also includes the effect of the valve shaft seal evaluation.

3. Better-off valve flow capacity, in particular, butterfly, butterfly plate flow resistance to small, over-current, to a large effective area. This requires a variety of voice, different types of valves should be the determination of flow resistance coefficient.

4. Body's ability to bear the water pressure should be consistent with the pipeline, that is, open the valve, the valve can withstand the test pressure pipeline requirements.

Third, valves lining and outer anti-corrosion

Is the transmission valve drinking water equipment, body lining must be non-toxic, corrosion-resistant, wear-resistant, smooth flow resistance as small as possible. If the valve plate, bolts and butterfly plates of different materials, it is prone to electrochemical corrosion, corrosion rust generated extending to the sealing surface, affecting the sealing effect of the valve, and valve wells installed in the valve, soak in water to prevent corrosion It is important, therefore, to cover perfect lining to prevent corrosion of the secondary pollution caused by water.

Valves can be taken outside the anti-corrosion after polishing sand-ching, for electrostatic spraying non-toxic anti-corrosion epoxy resin, can also brush 1-2 times Hongdan paint, brush and then twice in Antirust Paint.

Fourth, the valve operation and management

Good gate valve can not only appropriate valve selection, product quality, well construction and installation, but also thoughtful management, in order to play the role of "A Thousand Days Yang-bing, war time" effect. Good operation and management reflected in the following three aspects:

     1. Technical details are available

Valve valve factory technical information, including manuals, test the valve after the purchase of single-pass, valve assembly and the location of cards, valve maintenance record. Changes in the streets, the valve should be to update the card to establish a GIS management system.

2. Valve Operation and Management thoughtful

     Valve operation and management of quality requirements, including the valve should be closed tightly, the valve rod shaft seal packing string Department does not leak, the valve gate lightweight, well-directed. Valve operation and management of day-to-day operations, including gate valve, single previous approval of the records and operational records of the perfect, periodic testing of the gate valves and other records. Not for long-term operation of the valve off, according to the size of caliber, for the detection of different cycles is necessary. The fault should be found in the maintenance program, in time, especially after the closure of the valve can not open, like a burst pipe repairs as an emergency to deal with.

3. Well valve in good condition

Well the situation of valves including valve masonry well in line with industry standards and design specifications, and covers the road convergence intact, operate the valve hole bit accurate, wells and sewage debris-free, valve-free锈斑surface. Conditions permit, large diameter valves wells wells should be considered long-term convection air can be technical measures. Well on the valve should be inspected regularly, and covers the loss and damage should be dealt with promptly. 

  

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valve problems and the prevention of

Often happens after the factory valve problems caused by supply and demand should be the concern of both sides.

1, improper storage of

Valve can not open storage, should be placed in ventilation, dry place, the manufacturing plant, storage time should be required, to remove the valve can not be stored at both ends of the protective cover.

Lifting the valve actuator can not be as a lifting point, the attention can not be bumps flange.

2, the installation of inappropriate

Can not be used to support pipeline valves, flanges or welding to install client when the response to Qi, the pipeline to prevent stress caused by thermal expansion value.

3, improper welding

In accordance with the norms of the correct welding process;

Control of welding temperature, to prevent the sealing material damage.

Solder sealing ring before the Department with butter spread, the application of welding base to prevent welding spatter material embedded in the sealing surface.

4, start the process of the damage

Before the opening of the pipeline to be cleaned to remove dirt pipe rust, sediment, foreign body, to prevent damage to the sealing surface.

Valves can not for long remain in the semi-open semi-closed position.

Strength tests in the pipeline, be sure to complete emptying of liquid, the water valve will lead to chloride corrosion, strength test of the chloride content of the water required to control and add anti-corrosion agent.

5, the use of improper

Off valve can not be used to regulate flows, and is strictly prohibited in the semi-open semi-closed state of the use of wide-open valve position should be maintained at the location or total clearance.

6, corrosion

Selection of valve manufacturing and media must be considered H2S content and chloride content, material selection and heat treatment must comply with NACE MR-01-75 requirements

7, inappropriate choice of sealing materials

Selected as a rubber O-ring seal material, for pound Class600 level and above should be verified with optional explosion-proof vacuum (AED) of the material properties.

8, transmission problem

Valve position is not in place a recurring problem, the manufacturer must ensure that every aspect of transmission chain of the manufacturing accuracy, especially the pole then the ball valve, check valve before the factory switch location and the location of the consistency of instruction. valve ball valve gate valve check valve globe valve butterfly valve
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Standard pipeline ball valve

Pipeline ball valve design, manufacture, test specification standards are API standard 6D, the standard proposals for oil and gas industry to meet international standards of ISO13623 requirements of pipeline systems, the corresponding national standard is GB: 1, Full Bore or reduced bore diameter size according to the API standards 6D. 2, pipeline pressure valve according to API standard grade 6D, pressure temperature rating by ASME16.34. 3, a long pipeline to connect the valve according to API standards and tolerances 6D. 4, flange end of the size 24 "The following ANSI B16.5; 26" or above by ANSI B16.47. 5, butt welding end size according to ASME B 16.25. 6, flange face processing in accordance with ANSI B16.5. 7, excretory pore and the discharge hole diameter according to API standards 6D. 8, pressure test according to API Standard 6D and API Standard 598. 9, the fire safety design and test in accordance with BS6755, Part II; API Standard 607, API standard 6FA. 10, the material should be in accordance with ASME standards, as well as the corresponding NACE MR 0175, NACE MR 0103 standard. 11, valves and welding in line with the ASME Boiler Pressure Vessel Code section IX Welding and Brazing volume assessment, BS7448 Part II fracture toughness tests. 12, valve testing in line with the ASME Boiler and Pressure Vessel section V non-destructive testing, vol. 13, valve tags shall be in accordance with MSS-SP-25 or API Standard 6D. 14, ASME Boiler and Pressure Vessel Code section VIII rules of volume pressure vessel manufacture.

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Water supply network to choose the valve (a)

Water supply pipe network is all kinds of pipes and valves and other pipeline accessories, which consists of parts. According to a variety of needs (the water pipe network, the scheduling and allocation of water pressure, maintenance, repair of the water needs of old and new pipeline connections, pipeline cleaning, etc.) every day for the opening and closing valves. And quality of life of the valve determines the normal operation of networks in the pipe network plays a central role in the need to pay close attention.



As the water supply pipe network is connected between the enterprises and the users of the bridge, it can say: a water quality of enterprise management network in the normal operation; and the water supply network of the normal operation, but also and valves and quality of life is closely related to the.



Below the water supply network on the valve selection, offer a few comments.



1, the safety of water supply



Valve does not affect the water quality is an important indicator of choice. Valve direct contact with water is some of the main body inside, sealing parts, valves, etc., many valve manufacturers rubber sealing parts. Commonly used rubber material is nitrile rubber (NBR), chloroprene rubber (CR) or ethylene-propylene rubber (EPDM). These rubber is synthetic rubber. In the synthesis process, to add more than 10 kinds of natural rubber materials and additives, etc. Anti-aging. Can the ultimate synthesis of rubber seal for the water supply valve must be to see whether such a non-toxic rubber, with the drinking water health standards. As for the inside of the valve and valve parts, etc., many manufacturers of the past methods of painting, only the rust problem, without considering whether or not toxic. In practice, we find that: the water supply network, the pipeline corrosion problem lining, and pipe network is not lined valves, due to the phenomenon of water and the precipitation of iron bacteria in the water valve and the valve cavity and the erosion deposition, resulting in a number of body wall-like hills there depositions. Not only affected the quality of water supplies for a number of valves at the same time one of the main reasons poor clearance. Therefore, we ask, they come in direct contact with the water areas, should be non-toxic paint spraying, electrostati
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Unloading Relief Valve works with the primary purpose

 Unloading relief valve formed by the relief valve and one-way valve. When the system pressure to reach the opening pressure relief valve, relief valve opens, pump unloading; When the system pressure dropped to the closure of pressure relief valve, relief valve closed, pump to the system load. Unloading the pump when the pressure is called unloading pressure, so that the pressure pump in a loaded condition is called load pressure.

     Functions and Applications: The main function of unloading relief valve is the automatic control of pump unloading or loading. In view of the function of unloading relief valve to require unloading pressure and there are some differences between the load pressure. The difference is too small, then the unloading and loading pump action too frequently; the difference is too large, the system changed so much pressure.

     Load pressure and the pressure difference between unloading unloading relief valve is an important performance indicators, the general pressure loading unloading pressure of about 85%. The same as with the relief valve performance.

     Unloading relief valve of the main purposes:

     a. Accumulator pump system automatically unloading and loading;

     b. combination of high and low pressure pump high flow low pressure pump unloading.

     Manufacturers produce goods: domestic mainly Yuci hydraulic Group Co., Ltd., Beijing, China and Germany Hydraulic Group Co., Ltd., Shanghai Lixin Hydraulic Component Factory and so on. Outside the United States Vickers, Rexroth, Germany and other manufacturers.

     Unloading relief valve Germany choice: unloading relief valve used in hydraulic circuit with accumulator Germany, when the accumulator valve fluid-filled pressure of Germany set the pressure so that hydraulic pump unloading automatically. Valves have built-in check valve to prevent a pressure accumulator in the oil back. At this point from the accumulator and the pump to maintain oil unloading system to receive energy-saving effect. When the accumulator in the oil pressure dropped to the valve set pressure to about 85% when the valve is once set, hydraulic pump to restore the accumulator fluid-filled.

     This valve can also be used to double-pump high-low voltage circuits. When two low-pressure oil pump to the system at the same time, high pressure pump when the valve so that the major unloading and separating it with the high-pressure section.

     For the accumulator to the accumulator between the valve and shall not exceed the set pressure to drop to 10%. Leakage-type valve to vent the oil port back-pressure shall not exceed the set pressure to 2%. ball valve Trunnion Mounted Ball Valve Floating Ball Valve Top Entry Ball Valve ball valve
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A lot of market opportunities

 The international valve market can not tolerate us? Clearly not. It is understood that the Middle East as the world's most important oil-producing and exporting region, every country in the efforts to enhance oil production, but also increased the exploitation of oil and investment. The next few years in the north of Kuwait's largest oil and gas development projects currently in progress; Qatar will be the world's largest liquefied natural gas plant products; the United Arab Emirates through the construction of large-scale projects to increase crude oil production, crude oil production is expected to more than three million barrels; Abu Dhabi National Oil Company in the next 5 years a number of projects on an annual investment of 1.5 billion U.S. dollars, of which 40% for the oil industry ... ... and the requirements of each and every project is the largest valve products. On the other hand as a result of the Middle East, the Iraq oil fields, pipelines destroyed a powerful need to import oil by pipeline systems and valves, including API ball valve, gate valve, butterfly valve, check valve, globe valve,flat long-distance pipeline valves and ball valves and so on. These are the domestic valve manufacturer's main product is our strength. Why do we not get to do the business of their own this?

    

     Station to be eligible for future

    

     In fact, that as long as the needs of the market, domestic enterprises have become the valve of the international market is the key to great advantage. As long as the proper way, we can be our own station to the market prospects for the market to act as the protagonist.

    

     First export. Exports, including direct exports and indirect exports. Refers to the direct export products directly to businesses in the international market. It also has two ways: First, through foreign brokers, sold to local markets. The second is to set up their own enterprises in the foreign sales agencies, directly to the products sold to local customers. Indirectly refers to the export of domestic enterprises to export their products broker. The export is one of the most simple choice, it does not require full-time中售员and does not require huge capital investments, and flexibility, with less risk. But is also very obvious shortcomings, that is, companies can not directly involved in international sales activities, out of control on the export market, the market is limited feedback on the changes in the market it is difficult to make timely adjustments.

    

     Second, trade permits. Permit trade is granted by an authorized person has been authorized the right to have commercial value or technologies, including trade marks, patents, proprietary technology the right to use and so on. Valves due to the lack of domestic corporate management experience, a well-known brands and unique technology, use of the small. But it is also a direction of development, we can urge the companies to cultivate their own brands with independent intellectual property rights and development of technology.

    

     Third, foreign direct investment. Foreign direct investment refers to the actual ownership and control of foreign enterprises to participate directly in its management. From the equity point of view, it has two different forms, such as joint ventures. Refers to a joint venture enterprises in foreign markets with local businesses to operate a joint venture enterprise. Joint venture of local firms through the purchase of equity or co-financing a new business. The advantages of joint venture income larger, corporate marketing and production of control and market feedback. The disadvantage is that often a result of a partnership between the production and marketing have different views on the contradictions arising.

    

     Also such as sole proprietors. A sole proprietorship is an enterprise set up an independent production abroad. It can be through direct acquisition of existing local enterprises, can also create a new business. Owned enterprises can enjoy the advantages of the profits to obtain more experience in international marketing and market opportunities, the parent company of overseas subsidiaries have complete right to manage and control. The disadvantage is that large investment risks, uncertainties and more.
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Control valve stem seal of the new method

1, Introduction



Control valves, automatic control system is a very important, like people's hands and feet. Regulation of fluid flow control valve to overcome the interference to ensure the accused of variables to achieve a given process indicators.



Control valves by the valve inside the valve body parts and the composition of the inner valve spool pieces, including, stem, packing on the valve cover letter and so on. On the valve cover and fill for the letter of the stem seals and valve stem to guide, to prevent the process medium along the valve stem to control the outward leakage of movable parts, it is an integral part of valve body.



Conventional structure of the valve cover there are four general forms: ordinary type, heat sink type, long-necked and bellows-type seal. Materials are generally cast iron, cast steel and stainless steel, PTFE packing or letter is generally flexible graphite.



A typical control valve of the valve cover and valve body from the same material or equivalent material. Valve cover and valve body to bear the same temperature and corrosive effects of stem seal after a few hundred times after the cycle of action, they will wear, in engineering applications, the fluid pressure can lead to seal wear and tear; fill the choice is also a problem filling materials selection, control valves, increasing the friction caused by dead-zone control valves easily increase or stem seal failure.



Therefore, the choice of control valve, in addition to body structure, material, implementing agencies, the calculation caliber but also under the control of fluid pressure, temperature, pressure, fluid nature, a reasonable choice of the structure of the valve cover and fill the form of letters to to prevent fluid leakage along the control valve stem out, that should give full consideration to stem seal performance and service life. This is in engineering design it is very important.



Corrosion in strong, volatile and toxic and hazardous fluids in the process, control valves are generally not the ordinary type, heat sink type, long-necked type seal on the valve cover and structure, because such a structure of sealing performance and life of great limited. The author has done the scene in the production of related experiments, the use of 304 stainless steel control valves regulate straight trip concentrated nitric acid and concentrated sulfuric acid mixed acid flow, the use of PTFE packing seal structure, less than a month after about 600 of the control of the entire trip valve up and down movement of the rod, PTFE packing seal that is completely undermined. Corrosion in strong, volatile and toxic and hazardous process conditions, once the stem seal is damaged, strong corrosive, volatile and toxic and hazardous process media control valve stem from leaking out on the surrounding environment and personal security serious consequences.



Adopted the form of bellows-type seal of the problem is a way. Bellows made of stainless steel in general. This special structure to protect the valve cover of the fill control valves and fluid contact with you to avoid, once broken bellows, the bellows structure of the above letter will fill the bellows to prevent the breakdown of failure have serious consequences. In engineering practice, the form of bellows seal selection should take full account of the pressure of bellows sealed the rating would be higher with lower temperature, fluid particles can not have a solid presence, and corrugated pipe materials, such as the longest life cycle of action . Intolerance of certain processes in the stainless steel corrosion medium places strong corrosion, such as wet chlorine process medium, the wetlands of trace chlorine in hydrochloric acid containing stainless steel corrugated pipe will soon be corrosive, it can not be used to control valve stem bellows sealed form.



In this case, the right to choose seems to be the use of diaphragm control valve. Diaphragm control valves used in corrosion-resistant and corrosion-resistant lining membrane, do not fill, you can completely avoid the leakage of corrosive media field, but its not very good flow characteristics, and by the membrane lining of the restrictions, pressure, low temperature performance The most deadly is corrosion-resistant film will divide up and down folding as a result of damage caused by fatigue, a very short life span, once piece corrosion-resistant diaphragm rupture, strong corrosive, volatile and toxic and hazardous process media will be the same Department from leaking out of cracks, so diaphragm control valve by the use of a lot of constraints.



Therefore, in strong corrosion, volatile, toxic and hazardous process conditions, to find a reliable, economical and practical control valves on the valve cover and seal structure is to ensure reliable control valves work in order to achieve automatic control of the key production processes. 2, a new type of control valve stem sealing method



Nitrocellulose nitrification process that concentrated nitric acid and concentrated sulfuric acid and cotton fiber mixed reaction Nitrocellulose, control of concentrated nitric acid and concentrated sulfuric acid mixed acid flow and the ratio of the volume of cotton fiber is to ensure that the key to Nitrocellulose product quality. Nitrocellulose nitrification processes in the transformation of self-control system, we designed a new type of stem seal and successfully resolved the regulation of concentrated nitric acid and concentrated sulfuric acid mixed acid flow control valve stem seal problem.



PTFE packing seal in the top, we designed a cavity and the cavity to pass into the inert gas (such as nitrogen, can also be air), and requested the pressure inert gas pipeline to be slightly higher than the process the maximum pressure medium. In this way, control valves in the use of the process, even if the control valve of PTFE packing seal is damaged, due to the pressure of the gas pipeline to be slightly higher than the maximum pressure on media technology, strong corrosive, volatile, toxic and harmful gas can not leak out. Cavity in order to ensure the stability of gas pressure to prevent the gas valve stem up and down along the string gas in the cavity of the lower part of the PTFE packing divided into two parts from top to bottom, in the middle of a stainless steel pad traps will Viton O - stainless steel ring embedded in every other pad, the pad separated using PTFE packing its clamping. The upper cavity of the valve cover is also embedded in fluorinated rubber O-ring, and valve cover bolts will be pressed. In general, the fluorine rubber O-ring of life is relatively long, up to a million times, as long as the fluorine rubber O-ring seal is not damaged, cavity pressure inert gas pipeline technology has always been higher than the medium the highest pressure, the control valve stem sealing structure is very reliable and very economic.



3, Conclusion



That the control valve sealing structure in 2001, the company successfully used a modified nitrification process automatic control system, the realization of the production process of the nitrification process automation, control valve operation so far and there have never been as a result of the control valve stem packing seal damage resulted in concentrated nitric acid and concentrated sulfuric acid mixed acid along the valve stem to control the leakage of the accident.

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Valve leaked on the use of simple pre-installed on the technical requirements

Technical requirements for installation:



1, the valve should be installed before the cavity clean and remove the defects caused by transport;



2, leaked butterfly valve shaft is installed to maintain the level of the state was, piston valve upward vertical position;



3, the valve gear to deal with the use of pre-debug, and maintain the function of transmission intact, the limits of travel and over-torque control and reliable protection;



4, valve gear parts of the lubrication necessary to fully debug the use of pre-lubricating;



5, activated electric devices should carefully read the random electrical installation manual provided. 

  

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Automotive engine control valve of the principle of waveform analysis of fault (a)

1. Idle Speed Control (IAC) solenoid valve



Idle speed controller is designed in a number of mechanical and electrical and mechanical installations, in the electronically controlled engine management system, electronically controlled thermostat to replace the old plug, paraffin-type, vacuum tank, such as the location of similar devices. Idle speed electronically controlled solenoid valve to prevent idling of the stall, and enhance the stability of idling in the slow speed means used to reduce the classification of hydrocarbon HC emissions. Idle solenoid valve to maintain the idle speed as low as possible and not put out, even in the open air-conditioners, generators, ancillary facilities such as power steering increase the engine load can also be possible to maintain stability.



Idle speed controller is a number of solenoid valves (most Ford vehicles) and some rotary motor (European Bosch BOSCH), others are stepping DC Gear Motor (most applicable, Chrysler), but all the examples are by the control computer to change the signal amplitude or pulse width to the ultimate control of the operation of idling.



Idling by the sensor to detect engine speed, idle speed be adjusted in a predetermined set of procedures to maintain paragraph. Control of the computer such as air-conditioning compressor from the switch, battery charging indicator, power steering switch and the free / parking block of ancillary equipment such as switches to receive the digital input signal switches, each switch will trigger the compensation is scheduled to set the idle command and send it to idle speed controller, engine speed when the throttle to close to or below the minimum speed stability, Idle Speed Control system came into play often, electronically controlled idle air bypass the throttle valve to allow the flow to produce results similar to open throttle.



Test Method:



To make the engine idle operation and ancillary equipment (air conditioning, fans, wipers) on or off, if equipped with automatic transmission car in the parking stalls and switch between forward. This will change the engine load, causing the engine control computer to the idle valve to change the output command signal.



Waveform results:



Confirmed that compensation for a variety of idle mode waveform amplitude, frequency, shape, pulse width of scale, such as are found in the right context, and the repeatability and consistency.



Confirmed when the control signal changes the computer's command, the solenoid valve response, and changes in engine speed has also observed the emergence of the following circumstances:



Switch when the proportion of ancillary electrical equipment to open or close the block to block transmission, the control computer to control the idle speed will change the output command. Idle speed changes, Idle Speed Control Valve should open and close throttle bypass hole, if the idle speed remains unchanged, should doubt the next idle valve damage or obstruction.



Idle Speed Control valve in the diagnosis and control circuit, we should make sure that section of the vacuum leak check the air leakage or inappropriate, they will idle control system problem. 

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Smoke damSmoke damper valve applications in engineering quality requirements (c)

3.2, the installation of quality requirements



In day-to-day inspection of fire inspection and engineering work, I found the construction quality problems due to the installation of smoke caused by fire or valve failure to open problems, exhaust valves, exhaust port, fire dampers, fire reset Tuyere difficulties. This should be of great importance to the construction side, note the following installation requirements.



3.2.1, fire damper, exhaust valve should be strictly according to plan the construction of a separate hanger for support in order to avoid air duct at a high temperature deformation, the impact of valve function.



3.2.2, valves in the ceiling or in the installation of air duct should be on the board in the ceiling or walls of air duct into the hole for maintenance, the general into the pore size of not less than 450 × 450mm, in the conditions, the ceiling manholes can be reduced to 300 × 300mm.



3.2.3, fire damper and a firewall (or floor) between the duct should be used δ ≥ 1.5mm steel plate production, then the best for external use in the wind pipe insulation or refractory materials incombustibility protection, to ensure that firewall fire-resistant properties.



3.2.4, in the mechanical side of the operation of the valve should have a clear space of 350mm in order to facilitate maintenance.



4, fire, smoke valve in the works of some of the problems that exist in



I built the fire in the day-to-day trial, engineering check and acceptance work, found fire and smoke valves have a number of problems in the following for peer reference.



4.1, the fire control room to send the return air duct in his Department does not have to wear fire damper wall.



Pre-trial process in building and found that some of the works on the design of consumer control room to send back to the wind pipe through walls Department in its non-damper, which is "automatic fire alarm system design specifications" GB50116-98 in the first inconsistent with Article 6.2.2. For the purpose of fire damper fire control room in order to ensure fire safety.



4.2, fire control equipment to smoke, smoke control facilities, display imperfect



GB50116-98 in accordance with norms of the first provisions of Article 6.3.9: Fire Alarm confirmation, to stop supply of the parts of the air-conditioning, electric fire damper to close and receive the feedback signal; At the same time to start the relevant parts of the smoke and exhaust fan , exhaust valve, and to receive the feedback signal. Some projects can not be linked to control sub-control exhaust valves, exhaust port, and some can not receive the feedback signal, valves do not reflect the situation of the headstock.



4.3, pipeline gas fire extinguishing system without pneumatic damper.



GB50116-98 the first 6.3.4.3 requires: "In the delayed phase, should be self-closing fire doors, windows, ventilation and air conditioning system to stop the closure of fire dampers on the site." This requires a network of gas fire extinguishing system, must be installed on gas Dynamic fire dampers, and fire control equipment linked. In the absence of such features in the individual projects.



4.4, air supply and exhaust duct without sharing the remote control



The basement of some building, car parks combined use of air supply and exhaust duct, we found blower and exhaust valve in front of the scene can only manually, the control room of the remote control can not be achieved in normal times, blower, its front end valve was open the situation, in the event of fire, will take people to the scene to close the fan before the cut-off valve, which is very practical, directly affect the extraction system. Therefore, it is proposed to increase its cut-off valve remote control functions.



5, system debugging and maintenance and management of linkage



Fire damper, exhaust valve works in practice is not independent of Fire smoke products, but in the entire fire control system of linkage has its own unique logic of the relationship between linkage. Therefore, in order to ensure that its fire-fighting system to play a role in the system prior to acceptance by linkage requirements, must be fully debug, so that ventilation and air conditioning and smoke control system to meet regulatory requirements. Person should be carried out after acceptance of a planned day-to-day maintenance and management in order to protect the body in a normal situation, in the role of smoke in the Fire play their full role. 

  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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