The correct selection and pressure relief valve and matters needing attention

Pressure relief valve application scope is widespread, including yan industrial steam, compressed air, gas, water, oil and other liquid medium can be used, therefore, in the light of the many possible structural changes, when consider to choose the relief valve, the exact performance is one of the main valve. First of all should be fully tested to ensure good use effect. Choose principle 1, relief valve inlet pressure fluctuations should be controlled in inlet pressure - 80% of the given value 105%, such as more than the range, the performance of the relief valve will be affected. 2, usually after decompression valve valve pressure before Pc should be less than the valve of 0. Five times, namely, Pc 3, work in the medium temperature is higher, generally choose the guide piston type pressure relief valve or pilot operated relief valve bellows. 4. Medium for air or water, liquid, occasions, general appropriate chooses direct action film or pilot operated relief valve diaphragm pressure relief valve. 5, medium for steam, appropriate chooses the guide piston type pressure relief valve or pilot bellows type pressure relief valve. 6, convenient for operation, adjustment and maintenance, and pressure relief valves should be installed in horizontal pipe runs commonly. Choose note 1, within a given level of spring pressure, outlet pressure between the maximum and minimum values should be able to adjust continuously, can not have jam and abnormal vibration. 2, the outlet flow changes, its export direct acting pressure deviation is not more than 20%, guiding type is not greater than 10%. 3, for soft sealing pressure relief valve, can not have leakage within the given time, for the metal sealing and pressure relief valve, the leakage should be no greater than the maximum flow of 0. 5%. 4, when the inlet pressure change, its export direct acting pressure deviation is not more than 10%; Guiding type is not greater than 5%. 5, to sit idle and pressure relief valves, regulating spring should make it in a state of freedom. Import and export of client applications cover closed. 6, the relief valve flow related to the nature of the fluid and pressure ratio. The smaller the pressure ratio, the greater the flow; But when the pressure ratio was reduced to a certain value, flow no longer increases with pressure ratio decreases.