Pilot-operated safety valve (also known as pulse-type safety valve) is a safety valve that relies on the discharge of medium from the pilot valve to drive or control the main valve. The pilot valve itself is a standard spring-loaded safety valve. Safety valves are automatic valves, mainly used in boilers, pressure vessels and pipelines. The control pressure does not exceed the specified value, which plays an important role in protecting personal safety and equipment operation. According to the opening height of the safety valve disc, it can be divided into micro-opening safety valve and full-opening safety valve.
Classification of pilot-operated safety valves
The pilot-operated safety valve is divided according to the structural form, which can be divided into vertical hammer type, lever type, spring type and pilot type (pulse type); according to the structure of the valve body, it can be divided into two types: closed type and non-closed type. The closed safety valve means that the excluded medium does not leak out, and all of it is discharged along the outlet to the designated location. It is generally used in toxic and corrosive media. For air and steam safety valves, non-closed safety valves are often used. The selection of safety valve products should be determined according to the actual sealing pressure. For spring-type safety valves, within a nominal pressure (PN) range, there are springs with several working pressure levels. When ordering, in addition to specifying the type, name, medium and temperature of the safety valve, the sealing pressure of the valve body should also be specified. , otherwise it is supplied at the maximum sealing pressure.
Pilot operated safety valve features
Pilot-operated safety valves are suitable for high-pressure, large-diameter applications. The pilot-operated safety valve has good sealing performance, and its action is rarely affected by back pressure. The disadvantage of this safety valve is that its reliability is related to the main valve and the pilot valve, the action is not as fast and reliable as the direct-acting safety valve, and the structure is more complicated.