The safety valve is a pressure of pressure vessels, boilers, pressure piping system with a safety device to ensure the safe operation of pressure systems. The safety valve is in order to prevent the pressure equipment and containers, or easily cause pressure or container internal pressure exceeds the limits of a rupture of the safety devices.

When the container pressure exceeds the design requirements, the Pilot Safety Valve automatically opens, the exhaust gas to reduce the too high pressure inside, to prevent the vessel or pipeline damage. When the pressure down to normal operating pressure within the container, that is automatically shut down to avoid all gas container super-pressure discharge, resulting in waste and production interruptions.

The safety valve is mainly composed of three parts of the valve seat, valve (spool) and the loading mechanism. Seat some and body as a whole, some body assembly, it is connected with the equipment. The valve is often associated stem, it is closely linked to the seat. The valve above the loading mechanism can adjust the size of the load. When the pressure within the device within the working pressure range, the internal role of media in the valve above the force is less than the loading mechanism and the difference between the force of the valve above constitute the seal between the valve and valve seat force, so that the valve pressed with the valve seat, the device's media can not be discharged. When the equipment inside the pressure exceeds the pressure of work and achieve the safety valve opening pressure, the internal media in downtown valve above is greater than the loading mechanism to exert force on it, so the valve off its seat, the safety valve open media equipment discharged through the seat, if the safety valve discharge is greater than the device's safety discharge pressure device that is gradually decreased through the exhaust after a short time, the pressure drop back to normal operating pressure. At this point the internal pressure of the Gas Valve above force is less than the loading mechanism to exert force on it above the flap valve pressed forward seat, the media, to stop the discharge, the equipment to maintain a normal working pressure continues to run. Therefore, the safety valve is turned on or off by the ebb and flow of the media force on the valve and load the agency force, to prevent equipment overpressure.