Working principle of self-priming centrifugal pumps

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Working principle of self-priming centrifugal pumps 　　Working principle of self-priming centrifugal pumps 　　Commonly used self-priming centrifugal pumps all feature a pump casing design with axial liquid return. A self-priming centrifugal pump is mainly composed of components such as a suction chamber, a water storage cavity, a volute chamber, a return hole, and an air-water separation chamber. 　　The working principle of a self-priming centrifugal pump is as follows: Once the pump starts operating, the impeller draws in both the water that has been pre-filled in the storage chamber and the air drawn in from the inlet pipe. The water and air mix thoroughly as a result of the high-speed rotation of the impeller, and the liquid, along with the gas, is discharged toward the outer edge of the volute under the effect of centrifugal force. The liquid, carrying gas, enters the gas-water separation chamber through a diffusion tube. At this point, as the flow rate of water suddenly decreases, air – being a lighter gas than water – rises upward, and it is expelled from the gas-water mixture. The air then exits through the exhaust ports and drainage outlets of various self-priming pumps. After the air is separated, the water returns to the water storage chamber, and then via the return hole it goes back to the water intake end of the impeller, where it mixes again with the air drawn into the impeller through the inlet pipe of the self-priming centrifugal pump. Under the action of the rapidly rotating impeller, the water then flows toward the outer edge of the impeller. As this process repeats back and forth, the air in the inlet pipe of the self-priming centrifugal pump is continuously removed, until all the air in the inlet pipe is eliminated and a certain negative pressure is created. At that point, water will gradually be drawn from the tank into the pump, thus completing the self-priming process. Once water has been drawn in by the self-priming centrifugal pump, it can discharge water normally. That is the working principle of the self-priming centrifugal pump. 　　A cooling chamber can also be installed at the bottom of the bearing housing of a self-priming centrifugal pump to cool the bearings. If, due to installation or operation issues, the temperature of the bearing housing rises above 70 degrees, a coolant pipe can be connected there to allow coolant to be injected for circulating cooling.