Safety valve working principle and structure

gas valve play a security role in the system. When the system pressure exceeds a predetermined value, the valve is opened, the system part of the gas into the atmosphere, so that the system pressure does not exceed the allowable value, in order to ensure the system is not due to excessive pressure and accidents. Also known as relief safety gas valve.
structure type

1, piston valve
Spool is a tablet. Air pressure acting on the piston A, when the pressure exceeds the safety value determined by the spring force, the piston A is the top open portion of the compressed air that is discharged into the atmosphere from the valve port; when the air pressure is lower than the safety value, the spring drive piston down, closes the valve port.
2, valve and diaphragm valve
It works with piston identical. These three are the safety valve spring provides control, adjustable spring preload, you can change the size of the security value, so called direct-acting valve.
3, pilot valve
In a small direct-acting valve to provide control pressure acting on the diaphragm, the diaphragm is the hard core spool, the pressure on the valve seat. When the air pressure is greater than A safe pressure, open the valve, the compressed air is discharged into the atmosphere from the left side of the outlet opening. Diaphragm safety valve and pilot safety valve pressure characteristics of a good, quick action; however, the maximum opening force is relatively small, that is, poor flow characteristics. Practical application, should be based on actual need to select the type of safety valve, and to choose their path according to the maximum displacement.