Application of Back Pressure Valve in Metering Pump Installation

The function of the back pressure valve is mainly to maintain the pressure of the return pipeline to make the actuator move steadily, as well as the return path of the electro-hydraulic reversing valve used for neutral unloading, general relief valve, check valve, sequence valve. Can be used as a back pressure valve, an overview

Pumps, such as metering pumps, tend to overfeed when they are operated at low system pressures. In order to prevent similar problems, it must be at least 0.7Bar back pressure at the inlet and outlet of the metering pump. The purpose can be achieved by installing a back pressure valve in the outlet pipe of the metering pump.

Second, the main function

1. Provide pressure difference for the pipelines at both ends of the back pressure valve

2. It can be used as a safety valve in systems where the requirements are not very strict.

3. Use with pulsation damper to reduce the damage of water hammer to the system, reduce the peak value of flow rate fluctuation, and protect the pipeline, elbows and joints from pressure fluctuation.

4. Create a good working environment for metering pumps and improve pump performance.

Third, the working principle

The back pressure valve works by the spring force of the spring. When the system pressure is lower than the set pressure, the diaphragm will block the pipeline under the effect of spring 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.

Fourth, the use of back pressure valve

In the outlet line, the back pressure valve should be used simultaneously with the pulsation damper and the pulsation damper absorbs the flow peak between the pump and the back pressure valve. Without a pulsation damper, the back pressure valve will quickly open and close with each pump stroke. When there is a pulsation damper, the back pressure valve will oscillate in the half-open and half-close positions, so the pulsation damper can reduce the wear rate of the back pressure valve. For large flow pumps, where the outlet line is long and thin, the back pressure valve should be installed close to the filling point to reduce the siphoning tendency. When transporting a medium containing suspended solids, a tee (or four-way) with a pipe plug should be installed at the inlet end of the back pressure valve so that the pipeline can be cleaned without disassembly.

The back pressure valve is only a kind of pipeline component. Only with other pipeline components (such as pulsation damper, safety valve, check valve, and cut-off valve) can the maximum effect be achieved.

Fifth, selection guide

Pipeline diameters are DN6,8,10,15,20,25,32,40,50,65,80,100 twelve models.

The inlet pressure is 0.3MPa and 1.0MPa. The pressure difference between the inlet and outlet can be adjusted by adjusting the spring length.

Made of PVC (P), SS304/316 stainless steel (S), carbon steel (A)

The inlet and outlet connections are provided in three ways: internal thread, flange, and hose connector.

Based on the company's previous experience, available professional information and user-supplied process information, our company will recommend material contact materials to the user, and the user decides on the selection of materials.

Sixth, attention

1. Avoid resonance with the system.

2. When used with a pulsation damper, the pulsation damper should be installed between the pump and the back pressure valve to absorb the peak flow between the pump and the back pressure valve. Slow down the back pressure valve wear speed.

3, outdoor use should be added protective shelter or protective cover.

4. Before performing any maintenance on the back pressure valve, stop the operation of the equipment, release the pressure, close the valve connected to the system with the back pressure valve, and confirm that there is no pressure in the pulsation damper. Pay attention to prevent the body from being harmed by the liquid being transported during maintenance.

5. If the back pressure valve is reversed, the back pressure will increase exponentially, causing harm to the system and may be dangerous.

6. When the back pressure valve is found to be malfunctioning during operation, the power should be cut off in time.

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