Why Do Centrifugal Pumps Need To Install Bottom Valves

Aug 28, 2024

I believe we all know that a bottom valve should be installed at the inlet end of a centrifugal pump, but many people do not know why a bottom valve is installed and what the effect of installing a bottom valve is.
The reason why a centrifugal pump needs to be equipped with a bottom valve is that during the operation of the centrifugal pump, water must be introduced into the pump body and the entire inlet pipeline through a vacuum pump or other methods. When the impeller rolls rapidly, the blades cause the water to rotate rapidly, and the rotating water flies away from the impeller under the effect of centrifugal force. After the water in the pump is thrown out, the central part of the impeller forms a vacuum zone. The water from the water source is pressurized into the inlet pipe through the pipeline network under the effect of atmospheric pressure (or water pressure). By continuously cycling in this way, continuous pumping can be achieved.
If there is no bottom valve installed, when the centrifugal pump stops working, all the water in the pipeline will flow back to the water tank. This will require restarting the vacuum pump or refilling the centrifugal pump with water next time, which is time-consuming and laborious. If the centrifugal pump is equipped with a bottom valve, the bottom valve will automatically close under the pressure of water during shutdown, allowing water to remain in the pipeline. The next time, the centrifugal pump can be directly started, eliminating the need for water injection or opening the vacuum pump, which is very convenient.
It is worth noting that if the head of the centrifugal pump is high or the outlet pipeline is long, then the centrifugal pump needs to be equipped with a bottom valve to prevent water from causing the centrifugal pump to reverse during backflow, resulting in mechanical damage or impeller detachment.