Most of the media in chemical production equipment have the characteristics of high toxicity, flammability, explosiveness and strong corrosiveness. The working conditions are complex and harsh, and the operating temperature and pressure are high. Once the valve fails, the lighter will cause the medium to leak, and the heavyer will cause the device to stop. Stop production and even cause serious accidents. Therefore, the scientific and reasonable selection of industrial valves can not only reduce the construction cost of the device, but also ensure the safe operation of production. Key points of industrial valves selection guide 1. Clarify the purpose of the valve in the equipment or device Determine the working conditions of the valve: the nature of the applicable medium, the working pressure, the working temperature, and the operation control method. 2. Correctly select the types of industrial valves The correct choice of valve type is based on the designer's full grasp of the entire production process and operating conditions. When selecting the valve type, the designer should first grasp the structural characteristics and performance of each valve. 3. Determine the end connection of the valve Among threaded connections, flange connections, and welded end connections, the first two are the most commonly used. Threaded valves are mainly valves with a nominal diameter below 50mm. If the diameter is too large, it will be difficult to install and seal the connection. Flange-connected valves are more convenient to install and disassemble, but they are heavier and more expensive than screw-connected valves, so they are suitable for pipe connections of various diameters and pressures. Welding connection is more reliable than flange connection under more severe conditions. However, it is more difficult to disassemble and reinstall the valve connected by welding, so its use is limited to the occasions that can usually operate reliably for a long time, or where the use conditions are harsh and the temperature is high. 4. Selection of industrial valves material When selecting the material of the valve housing, internal parts and sealing surface, in addition to considering the physical properties (temperature, pressure) and chemical properties (corrosiveness) of the working medium, the cleanliness of the medium (with or without solid particles) should also be grasped. In addition, refer to the relevant regulations of the country and the user department. The correct and reasonable selection of the valve material can obtain the most economical service life and the best performance of the valve. The valve body material selection sequence is cast iron-carbon steel-stainless steel, and the sealing ring material selection sequence is rubber-copper-alloy steel-F4. 5. Other In addition, the flow rate and pressure rating of the fluid flowing through the valve should also be determined, and the appropriate valve should be selected using existing information (such as valve product catalogs, valve product samples, etc.). Commonly used industrial valves selection instructions 1. Selection instructions for industrial gate valves In general, gate valves should be preferred. In addition to suitable for steam, oil and other media, gate valves are also suitable for media containing granular solids and high viscosity, and are suitable for valves in venting and low vacuum systems. For media with solid particles, the valve body of the gate valve should have one or two purge holes. For low-temperature media, low-temperature dedicated gate valves should be used.                Gate Valve BS 5163 Flanged Resilient NRS, Type B (Z45XB), PN10/16                Flanged Gate Valve OS&Y Gate Valve (Z41X), UL/FM Approved 2. Instructions for selection of globe valve The stop valve is suitable for pipelines that do not require strict fluid resistance, that is, pipelines or devices with high temperature and high pressure medium that do not consider pressure loss, and are suitable for medium pipelines such as steam with DN<200mm. Small valves can choose globe valves, such as needle valves, instrument valves, sampling valves, pressure gauge valves, etc. The stop valve has flow adjustment or pressure adjustment, but the adjustment accuracy is not high, and the pipe diameter is relatively small, it is better to use a stop valve or a throttle valve. For highly toxic media, a bellows-sealed globe valve should be used; however, the globe valve should not be used for media with high viscosity and media containing particles that are easy to precipitate, nor should it be used as a vent valve or low vacuum system valve. 3. industrial ball valves selection instructions The ball valve is suitable for low temperature, high pressure and high viscosity medium. Most ball valves can be used in media with suspended solid particles, and can also be used in powder and granular media according to the sealing material requirements. The full-channel ball valve is not suitable for flow adjustment, but it is suitable for occasions that require fast opening and closing, which is convenient for emergency shutdown of accidents; usually in strict sealing performance, wear, necking passage, rapid opening and closing action, high pressure cutoff (large pressure difference), In pipelines with low noise, vaporization, small operating torque and low fluid resistance, ball valves are recommended. The ball valve is suitable for light structure, low pressure cut-off, and corrosive media; the ball valve is also the most ideal valve for low temperature and cryogenic media. For the piping system and device of low temperature media, it is better to use the low temperature ball valve with bonnet. When selecting a floating ball valve, its seat material should bear the load of the ball and the working medium. Large-caliber ball valves require greater force during operation. The 200mm ball valve should use worm gear transmission; the fixed ball valve is suitable for larger diameter and higher pressure occasions; in addition, the ball valve used for the process of highly toxic materials and flammable medium pipelines should have a fireproof and antistatic structure. 4. Description of throttle valve selection The throttle valve is suitable for occasions where the medium temperature is low and the pressure is high, and it is suitable for the parts that need to adjust the flow and pressure. It is not suitable for the medium with high viscosity and containing solid particles, and it is not suitable for the isolation valve. 5. Description of plug valve selection The plug valve is suitable for occasions that require fast opening and closing. It is generally not suitable for steam and higher temperature media, for lower temperature and high viscosity media, and also for media with suspended particles. 6. industrial butterfly valves selection instructions Butterfly valve is suitable for large diameter (such as DN﹥600mm) and short structure length, as well as occasions where flow adjustment and fast opening and closing are required. Generally used for water, oil and compressed air at a temperature of 80℃ and a pressure of 1.0MPa Medium: Because the pressure loss of butterfly valve is relatively large compared with gate valve and ball valve, butterfly valve is suitable for pipeline system with less strict pressure loss requirements.                Wafer Style Butterfly Valve BS EN 593 (D71X4, D371X4), PN10/16                Lug Butterfly Valve BS EN 593 (D71XL4, D371XL4), PN10/16 7. Check valve selection instructions Check valves are generally suitable for clean media, not for media containing solid particles and high viscosity. When DN≤40mm, lift check valve should be used (only allowed to be installed on horizontal pipelines); when DN=50～400mm, swing check valve should be used (can be installed on both horizontal and vertical pipelines, If installed on a vertical pipeline, the flow direction of the medium should be from bottom to top). When DN≥450mm, buffer check valve should be used; when DN=100～400mm, wafer check valve can also be used; swing check valve can be made into high working pressure, PN can reach 42MPa, It can be applied to any working medium and any working temperature range according to the different materials of the shell and seals. The medium is water, steam, gas, corrosive medium, oil, medicine, etc. The working temperature range of the medium is between -196～800℃.                Silent Check Valve (HC41X), PN10/16               Spring Check Valve EN 12334 Rubber Disc Swing Check H44J PN10/16 8. Diaphragm valve selection instructions Diaphragm valve is suitable for oil, water, acid medium and medium containing suspended solids whose working temperature is less than 200℃ and pressure is less than 1.0MPa. It is not suitable for organic solvent and strong oxidant medium. Weir diaphragm valves should be selected for abrasive granular media, and the flow characteristics table of weir diaphragm valves should be referred to for selection of weir diaphragm valves; straight-through diaphragm valves should be selected for viscous fluids, cement slurry and sedimentary media; diaphragm valves are not suitable for vacuum pipes except for specific requirements Road and vacuum equipment.Hope that this article is useful for you. If you are searching for the reliable industrial valves manufacturers, you can visit Shenzhen Mech Valve Trading Co., Ltd. Established in 1961, we are the large-scale enterprise group with advanced technology and equipment and strong comprehensive strength, known for its complete range of products, large producing capacity, high quality and strong R&D strength.

Industrial Valves Meaning & Definition The industrial valve is a device that guides or regulates flow by opening, closing or partially blocking a passage. If you want to become a pipeline expert, you also need to know about industrial valves and accessories. Without valves, there is no way to control pipeline flow. Let Mech Valve Manufacturer to discuss some industrial valves types and their applications with you. Gate Valve Gate valve is the most common form of valve in the industry. The gate is lifted and fluid in the pipeline starts to flow. Gate valves are designed to be fully open or closed; they are commonly used as shut-off valves to isolate piping systems. When the gate valve is opened, there is no blockage in the flow path, and there is little or no friction loss. When linear fluid flow is required and minimum restriction is required, gate valves can be used. The gate valve is usually controlled by a hand wheel, pneumatic diaphragm, electric motor or piston mechanism.                BS 5163 Flanged Resilient OS&Y Gate Valve, Type B (Z41XB), PN10/16                Flanged Gate Valve OS&Y Gate Valve (Z41X), UL/FM Approved Shut-off valve The stop valve is used to control the flow in the pipeline. It is different from the "full-pass or full-close" function of the gate valve. The stop valve is adjusted by the position of the movable disc (or plug) relative to the fixed ring seat. The port of the shut-off valve can be straight or angled. This type of angled feed valve is usually used for corrosive or viscous fluids that solidify easily. Needle valve The needle valve is essentially a shut-off valve used to control the flow very finely. The needle valve contains a slender tapered plug that can adjust the flow with high precision. Butterfly valve The butterfly valve is designed to adjust the flow, but its control capability is limited. This is a relatively simple industrial valve, which can be operated by rotating the handle 90 degrees.                Wafer Style Butterfly Valve BS EN 593 (D71X4, D371X4), PN10/16                Lug Butterfly Valve BS EN 593 (D71XL4, D371XL4), PN10/16 Check valve Check valves, also called NRVs, only allow fluid to flow in one direction. The purpose of check valves is to prevent backflow. There are many kinds of "stops" that can prevent backflow in the check valve. Ball check valves and piston check valves work with minimum pressure. The return force is not enough to bring the ball or piston back to the opposite direction. The flow in the rotating check valve pushes the hinged disc that opens only in one direction to ensure that fluid does not flow backwards.                Silent Check Valve (HC41X), PN10/16                Spring Check Valve EN 12334 Rubber Disc Swing Check H44J PN10/16 Safety valve The safety valve, also known as the safety valve, is an industrial valve and fittings whose installation purpose is to limit the pressure in the system. This type of angled air supply valve is strictly used to prevent overpressure that may cause damage to the system. Ball valve The ball valve has a very good closing function. A simple quarter turn of 90 degrees can fully open or close the valve. This feature can minimize the operating time of the valve and reduce the possibility of leakage due to wear of the gasket. If you are searching for high-quality industrial valves, you can visit Shenzhen Mech Valve Trading Co., Ltd., the professional industrial valves manufacturer in China. Our products include gate valve, y type strainer, pressure reducing valve, butterfly valve, check valve, widely applied in the field of a various kinds of industries. 

A valve is a device used to control the direction, pressure, and flow of fluid in a fluid system. It is a device that allows the medium (liquid, gas, powder) in the piping and equipment to flow or stop and can control its flow. The valve is a fluid delivery system. Preparation before operationBefore operating the valve, read the operating instructions carefully. Be sure to know the flow direction of the gas before operation, and check the valve opening and closing signs. Check the appearance of the valve to see if the valve is damp. If there is damp, it should be dried; if there are other problems, it should be dealt with in time, and no malfunction is allowed. If it is an electric valve that has been inactive for more than 3 months, check the clutch before starting. After confirming that the handle is in the manual position, check the insulation, steering and electrical wiring of the motor.Correct operation method of manual valveManual valve is the most widely used valve. Its hand wheel or handle is designed according to ordinary manpower, taking into account the strength of the sealing surface and the necessary closing force. Therefore, you cannot use a long lever or a long wrench to move. Some people are accustomed to using wrenches, and they should be strictly careful. When opening the valve, they should use steady force to avoid excessive force, which may cause opening and closing of the valve. The force should be steady and not impact. Some parts of high-pressure valves with impact opening and closing have considered that this impact force cannot be equal to that of general valves.    When the valve is fully opened, the hand wheel should be turned upside down to make the threads tightly to avoid loosening and damage. For rising stem valves, remember the valve stem positions when fully open and fully closed to avoid hitting the top dead center when fully open. And it is convenient to check whether it is normal when fully closed. If the valve stem falls off, or large debris is embedded between the valve core seal, the valve stem position will change when it is fully closed. Damage to valve sealing surface or valve hand wheel.    Valve opening sign: When the groove on the top surface of the valve stem of the ball valve, butterfly valve, and plug valve is parallel to the passage, it indicates that the valve is in the fully open position; when the valve stem rotates 90 left or right. When the groove is perpendicular to the channel, it indicates that the valve is in the fully closed position. Some ball valves, butterfly valves, and plug valves are opened with a wrench parallel to the channel, and closed when vertical. The operation of three-way and four-way valves should be carried out according to the marks of opening, closing and reversing. The movable handle should be removed after the operation is completed.    Correct operation method of safety valveThe safety valve has undergone pressure test and constant pressure before installation. When the safety valve is running for a long time, the operator should pay attention to checking the safety valve. During the inspection, people should avoid the exit of the safety valve, check the lead seal of the safety valve, pull up the safety valve with a wrench by hand, and open it at intervals. Drain the dirt and verify the flexibility of the safety valve.    Correct operation method of trapA trap is a valve that is easily blocked by debris such as water and dirt. When enabled, first open the flush valve and flush the pipeline. If there is a bypass pipe, the bypass valve can be opened for short flushing. For traps without flushing pipes and bypass pipes, remove the traps, open the shut-off flushing, then close the shut-off valve, install the trap, and then open the shut-off valve to activate the trap.    Correct operation method of pressure reducing valveBefore the pressure reducing valve is activated, the bypass valve or flushing valve should be opened to clean the pipeline dirt. After the pipeline is flushed, the bypass valve and the flushing valve should be closed, and then the pressure reducing valve should be activated. Some steam pressure reducing valves have traps before they need to be opened first, then slightly open the shut-off valve after the pressure reducing valve, and finally open the shut-off valve before the pressure reducing valve, watch the pressure gauges before and after the pressure reducing valve, and adjust the pressure reducing valve Adjust the screw to make the pressure after the valve reach a predetermined value, then slowly open the shut-off valve after the pressure reducing valve, and correct the pressure after the valve until you are satisfied. Fix the adjusting screw and cover the protective cap.If the pressure reducing valve fails or needs to be repaired, first slowly open the bypass valve and close the shut-off valve before the valve. Manually adjust the bypass valve roughly so that the pressure after the pressure reducing valve is basically stable at the predetermined value before closing. After the pressure reducing valve is replaced or repaired, it returns to normal.Correct operation method of check valveIn order to avoid the excessively high impact force at the moment of closing of the check valve, the valve must be closed quickly to prevent the formation of a great reverse flow velocity, which is the cause of the impact pressure when the valve is suddenly closed. Therefore, the closing speed of the valve should be correctly matched with the decay speed of the downstream medium.If the velocity of the downstream medium varies widely, the minimum flow velocity is not enough to force the closure to stop stably. In this case, the movement of the closing member can be suppressed by a damper within a certain range of its movement stroke. The rapid vibration of the closing parts will wear the valve moving parts too fast, leading to premature valve failure. If the medium is a pulsating flow, the rapid vibration of the closing member is also caused by extreme medium disturbance. Whenever this situation exists, the check valve should be placed where the medium disturbance is minimal.

Common occasions for various valves:Detailed description of valve types in China Valves can be divided into 10 categories according to different industry needs, with more than 3,500 varieties and more than 40,000 specifications. There are more than 2,300 manufacturers of valves in China.Detailed description of valve product types:1. City gas valves: City gas accounts for 22% of the entire natural gas market, and the valve usage is large, and there are many types. Ball valves, plug valves, pressure reducing valves, and safety valves are mainly required.2. Urban heating valve: In the urban heat generation system, a large number of metal sealing butterfly valves, horizontal balancing valves and direct buried ball valves are needed. Because of these valves, the longitudinal and lateral hydraulic imbalance of the pipeline can be solved to achieve energy saving and heat balance. purpose.3. Valves for urban construction: Urban construction systems generally use low-pressure valves and are currently developing in an environmentally friendly and energy-saving manner. Environmentally friendly rubber plate valves, balancing valves, mid-line butterfly valves, and metal-sealed butterfly valves are gradually replacing low-pressure iron gate valves. The valves used in domestic urban construction are mostly balance valves, soft seal gate valves, butterfly valves, etc.4. Environmental protection valve: In the domestic environmental protection system, the water supply system mainly needs the middle line butterfly valve, the soft seal gate valve, the ball valve, and the exhaust valve (used to remove the air in the pipeline). Sewage treatment systems mainly require soft sealing gate valves and butterfly valves.5. Valves for long-distance pipelines: Long-distance pipelines are mainly crude oil, finished products and natural pipelines. The valves that require a large amount of such pipelines are forged steel three-piece full-bore ball valves, sulfur-resistant slab gate valves, safety valves, and check valves.6. Valves for petrochemical plants: a, oil refining devices, valves used in refining devices are mostly pipeline valves, mainly gate valves, globe valves, check valves, safety valves, ball valves, butterfly valves, steam traps, among which, gate valve demand accounts for About 80% of the total number of valves, (valves account for 3% to 5% of the total investment of the device). b. Chemical fiber equipment, chemical fiber products mainly include polyester, acrylic and vinylon. Ball valve and jacketed valve (jacketed ball valve, jacketed gate valve, jacketed shut-off valve) for the valve to be used. c, acrylonitrile device. The device generally needs to use the api standard production valve, mainly for gate valve, globe valve, check valve, ball valve, steam trap, needle valve, plug valve, wherein the gate valve accounts for about 75% of the total valve. d, ammonia plant. Due to the different synthetic ammonia and purification methods, the process flow is different, and the technical performance of the required valves is also different. At present, domestic ammonia plants mainly need gate valves, globe valves, check valves, traps, butterfly valves, ball valves, diaphragm valves, regulating valves, needle valves, safety valves, and high temperature cryogenic valves. Among them, the stop valve accounts for 53.4% of the total valve data of the device, the gate valve accounts for 25.1%, the trap accounts for 7.7%, the safety valve accounts for 2.4%, the regulating valve and the cryogenic valve and other 11.4%.e, ethylene device, ethylene device It is a leading faucet for petrochemical industry, which requires a wide variety of valves. Gate valves, globe valves, check valves, and lift-rod ball valves account for the majority, with gate valves needing to take the lead. In the "10th Five-Year Plan", there are still 6 sets of ethylene plants with an annual output of 660,000 tons, and the demand for valves is considerable. In addition, large-scale ethylene and high-pressure polyethylene equipment also requires ultra-high temperature, lower temperature and ultra-high pressure valve series. f, air separation device. "Air separation" means air separation. The device mainly requires a shut-off valve, a safety valve, a check valve, a regulating valve, a ball valve, a butterfly valve, and a cryogenic valve. g, polypropylene device, polypropylene is easy to use propylene as raw material, polymerized polymer compound, the device mainly needs gate valve, globe valve, check valve, needle valve, ball valve, trap.7. Valves for power stations: The construction of power stations in China is developing in a large-scale direction. Therefore, large-diameter and high-pressure safety valves, pressure reducing valves, globe valves, gate valves, butterfly valves, emergency shut-off valves, flow control valves, and spherical seal instruments are required. Globe valve, (According to the national “Tenth Five-Year Plan”, except for Inner Mongolia and Guizhou provinces, it is also possible to build more than 200,000 kilowatts. Other provinces and cities can only build more than 300,000 kilowatts.)8. Valves for metallurgy: The behavior of alumina in the metallurgical industry mainly requires the use of wear-resistant slurry valves (in the flow-type shut-off valve) and the adjustment of traps. Metal-sealed ball valves, butterfly valves and oxidized ball valves, globe valves and four-way reversing valves are mainly used in the steelmaking industry.9. Marine flat valve: With the development of offshore oilfield exploitation, the amount of valves required for marine flat hair is gradually increasing. The offshore platform needs to use a shut-off ball valve, a check valve, and a multi-way valve.10. Valves for food and medicine: The industry mainly needs stainless steel ball valves, non-toxic all-plastic ball valves and butterfly valves. Among the above 10 types of valve products, the demand for general-purpose valves is much higher, such as instrument valves, needle valves, gate valves, globe valves, check valves, ball valves, and butterfly valves.