The name comes from Back Pressure Valve. It means that due to the function of the valve and the formation of a certain pressure, pressure can generally be adjusted. Can be used to control the flow of air, water, steam, various corrosive media, mud, oil, liquid metal, radioactive media and other types of fluids. The opening and closing part is a disc shaped valve plate, rotating around its own axis in the valve body, so as to achieve the purpose of opening and closing or regulation. It is mainly used for cutting and throttling in pipelines. The most commonly used systems are fluid metering and feeding systems, hydraulic control systems, chemical reaction conditions, critical state control and so on. It can be divided into two parts: regulation and overcurrent.
The back pressure valve is operated by the elastic force of the built-in spring: when the system pressure is smaller than the set pressure, the diaphragm plugs the pipeline under the action of the elastic force of the spring. When the system pressure is higher than the set pressure, the diaphragm compresses the spring, the pipeline is connected, and the liquid passes through the back pressure valve. The back pressure valve is similar to the check valve in structure, but the opening pressure is greater than the check valve, between 0.2 and 1.6 mpa.
In the pipeline or equipment vessel pressure unstable state, the back pressure valve can maintain the required pressure of the pipeline, so that the pump can be normal output flow. In addition in the end of the pump due to gravity or other effects often appear siphon phenomenon, at this time the back pressure valve can reduce the flow and pressure fluctuations due to siphon. For metering pumps and other positive displacement pump under low system pressure when working, there will be excess transport. To prevent similar problems, it is necessary to make the metering pump outlet at least 0.7Bar of back pressure, which is generally achieved by installing back pressure valve at the metering pump outlet.
1. The check valve on the outlet pipe is used to prevent liquid backflow, and the back pressure valve is used to maintain a constant pressure at the pump outlet.
2. Can be used as a safety valve in systems where requirements are less stringent.
3. Cooperate with the pulsating damper to reduce the harm of water hammer to the system, reduce the peak value of flow velocity fluctuation, and protect pipelines, elbows and joints from the impact of pressure fluctuation.
4. Create a good working environment for metering pump and improve pump performance.
5 to ensure the stability of water flow pump, such as some pump flow with pressure changes greatly, can be set at the outlet of the pump back pressure valve, so that the output flow of the pump is stable, then the general choice of back pressure valve for the actual use of the pump pressure or slightly less than the use of the pump pressure.
6. In the pipeline or equipment container pressure unstable state, can maintain the required pressure of the pipeline, so that the pump can be normal output flow.
7. In the outlet of the pump due to gravity or other role often appear gravity or siphon phenomenon, back pressure valve to reduce the flow and pressure fluctuation generated siphon, then general selection pressure is greater than the liquid itself, such as to prevent the liquid level is 2 meters medicine, can choose the back pressure valve of pressure is greater than 0.02 MPa, 0.1 MPa is generally selected.
