The safety valve plays a role of safety protection in the system. When the system pressure exceeds the specified value, the safety valve is opened to discharge part of the gas/fluid in the system into the atmosphere/pipe, so that the system pressure does not exceed the allowable value, so as to ensure that the system does not cause accidents due to excessive pressure.

There are two main types of safety valve structures: spring type and lever type. The spring type means that the seal between the valve clack and the valve seat depends on the force of the spring. The lever type relies on the force of the lever and the heavy hammer. With the need for large capacity, there is another impulse safety valve, also called pilot safety valve, which consists of a main safety valve and an auxiliary valve. When the medium pressure in the pipeline exceeds the specified pressure value, the auxiliary valve opens first, the medium enters the main safety valve along the conduit, and the main safety valve is opened to reduce the increased medium pressure.
The discharge of the safety valve is determined by the diameter of the valve seat and the opening height of the valve disc. It can also be divided into two types: the opening height of the micro-opening type is (1/20) ~ (1/40) of the inner diameter of the valve seat, and the full-opening type It is (1/3) ~ (1/4).
In addition, with different requirements for use, there are closed and unclosed types. The closed type means that the discharged medium does not leak, and all discharges along the specified outlet. It is generally used for toxic and corrosive media. The non-closed type is generally used for non-toxic or non-corrosive media.