HX3 band to take over the selection of the breathing valve of the breathing valve to determine the safety valve of the nominal operating pressure and temperature range determined by the operating temperature relief valve, spring or lever set pressure range determined by the calculated safety valve set pressure value, and then according to the decision to use media materials and structure type of safety valve, calculated according to the safety valve Discharge valve throat diameter. The following general rules of safety valve of choice. 
 Working principle 
 Breathing valve in the system from the security role. When the system pressure exceeds the set value, the breather valve Ting open, part of the system of gas into the atmosphere, so that system pressure does not exceed the allowable value, thus ensuring the system is not an accident due to the pressure is too high. Safety valve, also known as the relief valve. Icon for some of the typical structure of the safety valve. Figure a piston valve spool is a tablet. Gas source pressure on the piston A, when the pressure exceeds the safe value determined by the spring force, the piston A was to open the top part of the compressed air into the atmosphere from the valve port; when air pressure falls below a safe value, the spring-driven piston down, close the valve port. 
 Pilot breathing valve, a small direct-acting valve to control pressure on the diaphragm, the diaphragm hard core spool, the pressure on the seat. When the gas source pressure of A is greater than the safe pressure, the spool open, compressed air into the atmosphere from the left side of the output hole. Diaphragm safety valve and pilot safety valve pressure characteristics is sensitive; but the maximum opening force is relatively small, namely, the poor flow characteristics. Practical application, should be based on actual need to select the type of safety valve, based on the maximum displacement to choose their path. 
 Nominal pressure: PN0.5-16Mpa 
 Operating temperature :0-550 ℃ 
 Nominal diameter: DN15-150mm 
 Connection type: flanged, threaded, welded 
 Material: 304,316,304 L, 316L, SS316, WCB, WC6, WC9, CF3, CF8, cast steel, cast iron, ductile iron, forged steel, stainless steel and so on.