Safety valve is a kind of valve to prevent accidents in case of equipment failure. One of the important categories of safety valves is emergency automatic pressure relief valve (PRV). When the pressure or temperature exceeds the preset limit, it will automatically release substances from the boiler, pressure vessel or other systems. The pilot operated safety valve is a special type of pressure safety valve. It has good anti leakage effect, low cost and one-time emergency use. The devices with safety valve engineering are bursting discs or caps.