The Pressure Testing Methods for Pressure Relief Valve
There are many types of sanitary pressure relief valve. Piston type and spring film type are the main two types. Piston type pressure relief valve is a type of valve that uses piston for pressure relief. Spring film type pressure relief valve relies on spring and film for pressure balance.
The use of pressure relief valve:
Pressure relief valve is a kind of automatic valve that reduces the medium pressure to a certain value. Generally, the pressure after the valve is less than 50% of the pressure before the valve.
Pressure testing method:
The strength test of pressure relief valve is usually for assembly after test of single piece, or for test after assembly. The duration of strength test: 1 minute for DN<50mm; more than 2 minutes for DN65~150mm; more than 3 minutes for DN>150mm. After the bellows and the components are welded, apply 1.5 times the maximum pressure and use the air to perform strength test.
When performing the sealing performance test, it should be based on actual working medium. When tested with air or water, the test is to be carried out at 1.1 times the nominal pressure. When tested with steam, the test is to be carried out under the maximum working pressure allowed in operating temperature. The difference between inlet pressure and outlet pressure shouldn’t be less than 0.2MPa.
The testing method: after the inlet pressure is set, gradually adjust the regulating screw of the valve so that the outlet pressure can sensitively and continuously change within the range of maximum and minimum value without stagnation or jamming.