Self-priming pump is a special structure centrifugal pump that can work normally without refilling after the first filling. It can be seen that the self-priming pump is a special centrifugal pump. Self-priming pump is also known as self-priming centrifugal pump.

Self-priming principle

The self-priming pump can be self-priming, and its structure naturally has its special features. The suction port of the self-priming pump is above the impeller. After each shutdown, some water can be stored in the pump for the next start. However, before the initial start-up, it is necessary to manually add enough self-priming water to the pump, so that most of the impeller is submerged in water. After the pump is started, the water in the impeller is affected by centrifugal force and flows to the outer edge of the impeller, where it interacts with the gas at the outer edge of the impeller. Mixing to form a circle of foam belt-shaped gas-water mixture, the foam belt is scraped by the partition, so that the gas-water mixture enters the gas-water separation chamber through the diffusion pipe. At this time, due to the sudden increase of the water passing area, the flow rate decreases rapidly. , the relative density of the gas is small, it escapes from the water and is discharged by the pump pressure outlet, the relative density of the water is large, and it falls to the bottom of the gas-water separation chamber, and returns to the outer edge of the impeller through the axial return hole, and mixes with the gas again. With the continuous cycle of the above process, the vacuum degree in the suction pipe will continue to increase, and the water to be transported will continue to rise along the suction pipe. When the pump is completely filled with water, the pump will enter the normal working state and complete the self-priming process.

Comprehensive conclusion

The self-priming pump is actually a centrifugal pump with a special structure. After the structure of the self-priming pump is optimized, the water absorption performance is better and the water absorption is more convenient. Although the general centrifugal pump has a suction stroke, the water absorption is not as convenient as that of a self-priming pump, and the suction stroke is not as high as that of a self-priming pump. Especially the jet self-priming pump, the suction stroke can reach 8-9 meters. The general centrifugal pump can not. But for general use, there is no need to deliberately choose a self-priming pump, just choose a general centrifugal pump.