Selection principle of safety valve

1, the steam boiler safety valve, generally choose all open and S10 spring safety valve series; 2, liquid medium with safety valve, generally choose micro and S10 spring safety valve series; 3, air or other gas medium with safety valve, generally choose spring safety valve closed and all type; 4 in rail tanker car tank lorry or liquefied petroleum gas (LPG), liquefied petroleum gas with safety valve, general use full rev built-in safety valve; 5, production export with safety valve, general use pilot operated safety valves; 6 high pressure bypass safety valve, steam power generation equipment, has a dual function of safety and control is generally selected pilot operated safety valves 7, if you want when you start the test on a regular basis for safety valve, safety valve should be chosen with ascension wrench. When the medium pressure reaches more than 75% of the opening pressure, can use a wrench on the valve disc from the valve seat ascension slightly, to check the safety valve opens flexibility; 8, if the medium temperature is higher, in order to lower the temperature of the spring chamber, generally when the enclosed safety valve temperature over 300 ℃ and open type safety valve temperature exceeds 350 ℃, should choose safety valve with radiator; 9, if security back pressure valve outlet is changing, the change amount by more than 10% of the opening pressure, should choose bellows safety valve; If, corrosive medium, should choose bellows safety valve, prevent important component failure due to corrosion by the medium. 11, the safety valve of the installation construction, installation and maintenance should be paid attention to the following points 1) , installation position and height, import and export direction must comply with the design requirements, pay attention to the medium flow direction should be consistent with the valve body the direction of the arrow, connection should be strong. 2) , valve door appearance inspection must be conducted before installation, the valve nameplate of the door should be consistent with existing national standards 'universal signal valve door' GB 12220. For the working pressure is greater than 1. 0 MPa and gate valve with the function of cutting on ZhuGanGuan, strength and strict performance test should be done before the installation, qualified rear must use. Strength test, the test pressure for the nominal pressure of 1. 5 times, duration of not less than 5 min, the valve door shell, packing should be no leakage as qualified. Leak test, the test pressure for the nominal pressure of 1. 1 times; The duration of the test meet the requirements of GB 50243. 1. All kinds of safety valve should be installed vertically. 12, the safety valve outlet should be without resistance, avoid to produce compression phenomenon. 13, safety valve should be specially test before installation, check and its official seal. 14 and the use of the safety valve should be checked regularly.