Self-priming pump is pump in the start before no need to add water or vacuum (the first boot should be filled with water), after a short time operation, depending on the role of the pump itself, the water suction and normal operation of a pump. The main hydraulic components of the self-priming pump impeller and pump shell are similar to the general centrifugal pump. WFB self-priming pump without seal shall be the auxiliary impeller power seal, also known as hydrodynamic seal. It can overcome some deficiencies of packing seal and mechanical seal to ensure no leakage.

WFB vertical unsealed self-priming pump. JPG

WFB self-priming pump without seal is mainly composed of pump body, working impeller (main impeller), auxiliary impeller, pump shaft, motor support, electric control valve, stop check valve and other devices. Working principle of gas liquid hybrid, before the pump is running, there is a certain amount of liquid in the pump body, pump starts, due to the rotation of the impeller, work is making the air and into the liquid pipe of liquid in the pump body mix, and have been to the gas-liquid separation chamber, gas liquid separation indoor air from the upper escape, fluid returning from the lower impeller imports, and again into the liquid pipe residual air mixing, cycle, until all the air in liquid into the tube row, complete the imbibition.

The principle of auxiliary impeller dynamic seal: the auxiliary impeller is in the upper part of the working impeller, which rotates together with the working impeller during operation. Its function is to reduce the pressure of the pump chamber, to achieve the balance of axial force and prevent liquid from entering the sealing device. Vice impeller is actually rely on pressure to withstand the high pressure of the impeller outlet leakage, when the vice impeller does not work, so should be equipped with stop sealing, to prevent the outflow of water pump chamber.

Because the hydraulic loss in the pump cavity of WFB vertical self-priming pump is larger than that of the general centrifugal pump, the power used is relatively large.

As one of the components of the self-priming pump, the electronic control valve of WFB self-priming pump is mounted on the intake pipe of the suction port. When the pump is started, the electronic control valve closes the air inlet on the suction pipe of the pump body to form a vacuum in the pump chamber and complete the whole process of self-priming. When the pump is stopped, the electric control valve opens and air enters the pump liquid pipe from the closed mouth to quickly isolate the common flow medium in the suction pipe to ensure that the medium in the pump chamber does not fall back to the suction pool with the medium in the suction pipe cavity to achieve the purpose of eliminating the siphon and ensure the normal self-priming and operation of the self-priming pump during the second self-priming. After the stop of the self-priming pump, the outlet check valve is closed by backwater gravity, so that the liquid in the pump chamber will not flow out.