Plastic safety valve back pressure valve

Safety valve (also known as pressure relief valve, back pressure valve) is automatically open and close according to the working pressure (working temperature) of the system. It is generally installed on the equipment or pipeline of the closed system to protect the system safe. When the pressure or temperature of the equipment or pipeline exceeds the set pressure of the safety valve, the pressure relief or temperature drop will be automatically opened to ensure that the medium pressure (temperature) in the equipment and pipeline is under the set pressure (temperature), so as to protect the normal operation of the equipment and pipeline, prevent accidents and reduce losses. Safety valve is widely used in: steam boiler, liquefied petroleum gas tank car or liquefied petroleum gas railway tank car, oil production well, high pressure bypass of steam power generation equipment, pressure pipeline, pressure vessel, etc. Safety valve is generally divided into spring type safety valve, lever type safety valve and pulse type safety valve. Plastic safety valve is a spring-loaded safety valve, which is divided into UPVC safety valve, CPVC safety valve and PVDF safety valve according to the material. The connection mode is socket welding and flange. The diameter of PVC safety valve is between dn15mm and dn80mm. The valve body material of plastic safety valve is PVC, CPVC, PVDF, PP, etc., and the seal is PTFE. Applicable to the pipeline system of corrosive medium. Use and adjust the pressure to 0.1 to 1.6Mpa

Spring type plastic safety valve
Spring type plastic safety valve uses the force of compression spring to balance the force acting on the valve disc. The compression of the coil spring can be adjusted by turning the adjusting nut on it. With this structure, the opening (setting) pressure of the safety valve can be corrected as required. The spring micro lift safety valve has the advantages of light and compact structure, high sensitivity, unrestricted installation position, and small sensitivity to vibration, so it can be used on mobile pressure vessels. The disadvantage of this safety valve is that the load applied will change with the opening of the valve, that is, with the increase of the valve disc, the compression amount of the spring increases, and the force acting on the valve disc also increases. This is not good for quick opening of safety valve. In addition, the spring on the valve will reduce its elasticity due to the influence of high temperature for a long time. When it is used on the container with high temperature, it is often necessary to consider the heat insulation or heat dissipation of the spring, so that the structure becomes complex.