There are many types of self priming pumps, among which the working principle of the external mixing self priming pump is to fill the pump casing with water (or to store water within the pump casing) before starting the centrifugal pump. After startup, the high-speed rotation of the impeller causes the water flow in the impeller channel to flow towards the vortex shell. At this time, a vacuum is formed at the inlet, causing the inlet check valve to open. The air in the suction pipe enters the pump and reaches the outer edge through the impeller channel. On the other hand, the water discharged into the gas-water separation chamber by the impeller flows back to the outer edge of the impeller through the left and right return holes. The water flowing back from the left return hole, under the action of pressure difference and gravity, shoots into the impeller channel and is crushed by the impeller. After mixing with the air from the suction pipeline, it is thrown towards the volute, and the corrosion resistant pump, acid resistant pump, and fire pump of the submerged pump move in the direction of rotation. Then it converges with the water flowing from the right backwater hole and moves along the snail shell. Because the liquid continuously impacts the cascade inside the volute and is constantly crushed by the impeller, it is strongly stirred and mixed with air, resulting in a mixture of gas and water, and constantly moving, causing negative gas and water to be unable to separate. The mixture is separated by the tongue at the outlet of the volute and enters the separation chamber along the short tube. The air in the separation chamber is separated and discharged through the outlet pipe, while the water still flows towards the outer edge of the impeller through the left and right return holes and mixes with the air in the suction pipe. Repeat the cycle and gradually exhaust the air in the suction pipeline, allowing water to enter the pump and complete the self priming process. Sewage pump, self priming pump, oil pump
The working principle of an internal mixed self priming pump is the same as that of an external mixed self priming pump, except that the return water does not flow to the outer edge of the impeller, but rather to the inlet of the impeller. When starting an internal mixing self priming pump, the reflux valve below the front of the impeller must be opened to allow the liquid in the pump to flow back to the inlet of the impeller. Under the high-speed rolling action of the impeller, water mixes with the air from the suction pipe, forming a gas-water mixture that is discharged into the separation chamber. Here, the air is discharged and the water returns from the return valve to the impeller inlet. Repeat this process until the air is exhausted and water is sucked in.