Safety of pneumatic valve selection more secure

Pneumatic valve is a kind of safety for pressure equipment, containers, or automatic pressure relief devices in the line. When be protected in the system pressure exceeds allowable values, pneumatic valve automatically open, get rid of some redundant medium, in order to prevent the system pressure continues to rise, when the system pressure down to a specified value, pneumatic valve can automatically shut down again, so as to ensure the normal operation of the system. Security pneumatic valve of the main performance indicators are:


1) Security. Pneumatic valve factory according to the relevant national standards for the strength test and sealing test, to ensure that the mechanical properties of the pneumatic valve meets the requirement of national standard.
2） Sensitivity. Pneumatic valve jump bar pressure, back pressure, within the scope of the national standards and user requirements, accurately and quickly jump jump pressure, back pressure stability.
3） Sealing. Pneumatic valve back seat, sealed performance is good, no leakage.
4） Emissions requirements of safety pneumatic valve, pneumatic valve after takeoff emissions to reach the requirements of the national standard of mechanical properties, pneumatic valve sealing performance and other performance is stable, no change.








how to correctly choose the safety of pneumatic valve is directly related to the economic benefits of units used and operation safety of personnel and equipment, the following authors choose the general rules of safety of pneumatic valve:
1) According to the calculate and determine the safety of pneumatic valve 'nominal size need to make the security of the pneumatic valve discharge capacity of pressure vessel or safety valve capacity.

　 2） According to the pressure vessel design pressure and design temperature determine the safety of the pneumatic valve pressure rating.
　 3） Steam boiler or steam pipeline in not normally closed with a wrench and all pneumatic valve type safety. To the security of open pressure is greater than 3 mpa steam with pneumatic valve or the gas medium temperature over 320 ℃ with the safety of the pneumatic valve, should be chosen with radiator ( Fin) In the form.
　 4） Hot water boiler is not closed with a wrench is commonly used in micro and pneumatic valve type safety.
　 5） For air, not against media such as more than 60 ℃ hot water or steam, with pneumatic wrench safety valve should be adopted.
　 6） The incompressible liquid medium such as water generally use safety mini rev type pneumatic valve closed, or use the safe discharge of pneumatic valve.
　 7） High pressure water supply with normally closed all rev type pneumatic safety valve, such as high pressure feed water heater, heat exchanger, etc.
　 8） Gas compressibility, such as medium with normally closed all rev type pneumatic safety valve, such as gas storage, gas pipelines, etc.
　 9） Large diameter, large displacement and high pressure system with general pulse pneumatic valve type safety, such as reduction of temperature and pressure relief devices, power plant boiler, etc.
　 10） For flammable, toxic to extreme or highly harmful medium closed-end security should be used in pneumatic valve, for use with hoisting mechanism, it should be enclosed with the wrench safety pneumatic valve.
　 11） When security pneumatic valve is likely to bear back pressure changes and changes in quantity more than 10% opening pressure vessel or piping system or toxic flammable, should choose to take the safety of the corrugated pipe pneumatic valve.
　 12） May produce negative pressure in the process of negative pressure or operating systems generally use pneumatic vacuum negative pressure safety valve.
　 13） Medium to low freezing point systems generally use heat preservation jacket type safety pneumatic valve.
　 14） The train transport liquefied petroleum gas tank car, car tanker, tank should be adopted such as built-in security pneumatic valve.
　 15） Tank roof generally use pneumatic hydraulic safety valve, should be used with breathing pneumatic valve.
　 16） Underground drainage or gas pipeline pilot operated safety is commonly used in pneumatic valve.
　 17） Liquefied petroleum QiZhan liquid-phase reflux tank pump discharge line security reflux is commonly used in pneumatic valve.
　 18） According to the medium characteristics to choose the appropriate safety pneumatic valve material. Such as ammonia containing medium can't choose the safety of the copper or copper pneumatic valve; Acetylene cannot use containing copper or copper 70% safety pneumatic valve.
　 19） For the working condition of discharge in large volumes, should choose the rev type; For stable working pressure, working condition of discharge in small volumes, appropriate chooses tiny qi type; For high pressure, working condition of discharge in large volumes, appropriate chooses the starting system directly, such as pulse pneumatic valve type safety. For container length more than 6 m should be set up two or more than two security pneumatic valve.
　 20） E steam boiler or low working pressure Pw stationary containers, can use the static weight type ( The pressure cooker) Or pneumatic valve lever and weight type safety. Mobile equipment should adopt pneumatic valve spring type safety.
　 21） For thicker and easy blockage of medium, appropriate chooses security pneumatic valve and the discharge of the series combined device of the blasting.
　 22） Nominal pressure pneumatic valve size to choose according to the safety work of the spring pressure rating. Security pneumatic valve nominal pressure relationship with spring working pressure.