What is a check valve? Do I need a check valve?

Check valve is a valve used to prevent the back-flow of the piping system. The pressure of the liquid through the pipeline will open the valve, and any reverse flow will close the valve. When the pump is turned off, the check valve will help your water system maintain pressure and prevent kickbacks, upper thrust and water hammer.

It is recommended to install at least one check valve in all submersible pump devices. Many oil well pumps have built-in check valves. Even if the pump has a built-in check valve, we recommend installing a check valve below the drain pipe and water supply level within 25 feet of the pump. Although installers have different opinions, in deep wells, we recommend installing check valves every 200 feet to distribute the weight of each valve.

What type of check valve do I want? The swing check valve should not be used for submersible pump installation. The reaction time of the swing check valve is slow, which will cause water hammer. Spring check valves should be used when closing quickly to help prevent water hammer. Its size should be appropriate to meet the flow and pressure conditions of the pump. The rated pressure of the check valve must exceed the maximum pressure of the pump.

Backspin, upthrust and water hammer may cause early failure of the pump or motor.

Backspin. When the motor stops running, when there is no check valve or the check valve fails, the water in the downpipe can flow out of the discharge pipe. The flow will cause the pump to rotate in reverse. If the pump starts during the pin-back process, excessive force may be generated, causing the pump shaft to break, impeller damage, or bearing damage.

Upthrust. If the check valve fails or there is no check valve, the pump will start at zero head. When the pressure is low or no pressure, the impeller will "float" and wear on the diffuser above. This repeated wear and tear can cause premature failure of the pump and motor.

Water hammer. Check valve failure or leakage may cause vacuum in the discharge piping. When the pump starts, the water moves at a very high speed, filling the gap and hitting the fixed water in the upper pipe, causing a hydraulic shock. Shock can cause pipe rupture, joint breakage, or damage to the pump and motor.

The above information is provided by wholesale check valve supplier.