Safety valve is a kind of safety protection valve, also known as exhaust valve, a kind of automatic valve. Its opening and closing parts are normally closed under the action of external force. When the pressure in the equipment or pipeline exceeds the set pressure of the safety valve, the pressing force is adjusted by adjusting the length of the spring force in the valve. When the pressure in the pipeline is higher than When the set value is set, the spring is reversely compressed and the oil leaks out, thereby controlling the pressure in the pipeline not to exceed a certain limit value, ensuring that the pressure of the medium in the equipment and the pipeline is below the set pressure, and protecting the equipment and the pipeline in normal Work to prevent accidents and reduce losses.