DN15/20/25 UPVC Back Pressure Valve Plastic Pressure Relief Valve, Safety Valve for Metering Pump, Diaphragm Corrosion Resistant

First, 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 blocks the pipeline under the action of the spring elastic force; 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.

In the state of unstable pressure in the pipeline or equipment container, the back pressure valve can maintain the pressure required by the pipeline, so that the pump can output the flow normally.

In addition, siphon phenomenon often occurs at the pump outlet due to gravity or other effects. At this time, the back pressure valve can reduce the flow and pressure fluctuations caused by siphon.

In order to prevent similar problems, the outlet of the metering pump must have a back pressure of at least 0.7 Bar, usually by installing a back pressure valve at the outlet of the metering pump.

Second, the main function of the back pressure valve safety valve
1. The one-way 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.

It can be used as a safety valve in the system.Used in conjunction with pulsation dampers to reduce water hammer, reduce the peak value of flow rate fluctuations in the system, and protect pipelines, elbows, and joints from pressure fluctuations.
2. Create a good working environment for metering pumps and improve their performance
To ensure the stability of the pump outlet flow, if the flow rate of some pumps varies greatly with pressure, a back pressure valve can be installed at the outlet of the pump to stabilize the output flow of the pump. At this time, the pressure of the back pressure valve is generally selected as the actual operating pressure of the pump or slightly less than the operating pressure of the pump.
3. Under the condition of unstable pressure in the pipeline or equipment container, the pressure required by the pipeline can be maintained, so that the pump can output the flow normally.
In the pump outlet due to gravity or other effects often occur due to self-flow or siphon phenomenon, back pressure valve can reduce the flow and pressure fluctuations caused by siphon, this time generally choose greater than the liquid's own pressure, such as to prevent the liquid level of 2 meters in the medicine cabinet self-flow, can choose a pressure greater than 0.02MPa back pressure valve, generally choose 0.1MPa can be.

Third, the working principle of the back pressure valve safety valve
Fluid enters through the back pressure valve inlet and is blocked by the diaphragm, causing upward pressure on the diaphragm.When the pressure is high enough, the spring is compressed, and the fluid pushes up the diaphragm to form a channel and flows out from the back pressure valve outlet; if the fluid pressure is not enough, it will form a holding pressure, causing the inlet pressure to rise until the rated pressure is reached, and the diaphragm is pushed up to form a passageway.

The rated pressure of the back pressure valve can be adjusted, usually by adjusting the ejector rod at the upper end of the spring, thereby adjusting the length of the spring.