Although the working principle of centrifugal pump is to use atmospheric pressure, atmospheric pressure only affects the suction head and has no effect on the hydraulic head. The impeller is driven by the motor to rotate at high speed, and the water in the pump casing also rotates at high speed with the impeller and is thrown into the outlet pipe at the same time. At this time, the pressure near the rotating shaft of the impeller is reduced, and the atmospheric pressure forces the lower water to push open the bottom valve and enter the pump casing along the inlet pipe, and the incoming water is thrown into the outlet pipe by the impeller ... so the water is continuously pumped to a higher place. It can be clearly seen from this passage that the water in the outlet pipe is thrown up by the impeller rotating at high speed. Therefore, the lift of the pump is determined by the power of the motor or other power equipment. As long as the power of the power equipment is large enough, the pumping head can completely exceed 10 meter.
Although the head of water pump refers to the height difference between two water surfaces, it is actually affected by pipeline resistance, which will subtract part of the head.
Therefore, the actual head of centrifugal pump mainly depends on the actual hydraulic head, which is determined by the power of power equipment, while the actual suction head is determined by atmospheric pressure and power equipment. The role of atmospheric pressure here is mainly "supplementary supply".