The commonly used self-priming pump refers to the externally mixed centrifugal self-priming pump. According to the rotation of the impeller, the liquid flows to the volute, thus forming a vacuum in the pump body. In this way, the one-way valve of the self-priming pump will open, suck the liquid in from the inlet, and deliver the liquid out through the impeller flow channel. This is the working principle of the self-priming pump.

Self priming pump differs from centrifugal pump in that it does not need to fill water when it is used. However, you must remember to fill the pump cavity with water when you first use it, because the pump itself does not store liquid. If you do not fill the pump cavity with water when you first use it, the pump will run idle. Not only can you not suck up the liquid, but also it will burn the pump body's mechanical seal and other accessories because of idling, so you must pay attention to this. So do you need to install the bottom valve for the self-priming pump

01. If the bottom valve is not installed, what is the situation?

In general, there is no need to install a bottom valve, because generally the inlet of the self-priming pump is equipped with a check valve, which is often referred to as a one-way valve. In this way, after the pump stops, the liquid in the pump cannot return to the original pool and is stored in the pump, so it is not necessary to add liquid when it is used for the second time,

02. What if the bottom valve is installed?

The effect will be better if the bottom valve is installed, because if the check valve is damaged sometimes, the bottom valve will also be used as a guarantee to prevent idling, and the effective suction head of the pump will also be effectively guaranteed after the bottom valve is installed!

In another special case, if the difference in suction height is too large, or the diameter of the suction pipe is too large, and the volume exceeds the liquid storage in the self-priming pump cavity, it will not work normally. At this time, the bottom valve must be installed to ensure safe and fast self-priming.