The commonly used self-priming pump refers to an external hybrid centrifugal self-priming pump. According to the rotation of the impeller, the liquid flows towards the volute shell, thereby forming a vacuum in the pump body. In this way, the one-way valve of the self-priming pump will open, sucking the liquid in from the inlet and conveying it out through the impeller channel. This is the working principle of the self-priming pump.
A significant feature that distinguishes self-priming pumps from centrifugal pumps is that they do not require watering during use. However, it is important to remember to fill the pump chamber with water during the first use, as there is no liquid stored in the pump body itself. If water is not filled during the first use, the pump will run idle, not only failing to suck up the liquid, but also burning out the pump body's mechanical seal and other accessories due to idle operation. Therefore, this must be taken into consideration.
So does a self-priming pump need to install a bottom valve?
Generally speaking, it is not necessary to install a bottom valve because the inlet of a self-priming pump is equipped with a check valve, also known as a one-way valve. After the pump stops, the liquid in the pump cannot flow back to the original pool and is stored in the pump body. Therefore, there is no need to add liquid for the second use.
What is the situation if the bottom valve is installed?
If a bottom valve is installed, the effect will be better because sometimes the one-way valve is damaged, and the bottom valve serves as a guarantee to prevent idling. Moreover, installing a bottom valve will effectively ensure the effective suction of the pump!
Another special situation, but if the suction height difference is too large or the suction pipe diameter is too large, and the volume exceeds the liquid storage capacity in the self-priming pump chamber, it cannot work normally. At this point, a bottom valve must be installed to ensure safe and fast self-priming.
