A Water Pump Is A Machine That Transports Or Pressurizes A Liquid

A pump is a machine that transports or pressurizes a liquid. It transmits the mechanical energy of the prime mover or other external energy to the liquid to increase the energy of the liquid. It is mainly used to transport liquids including water, oil, acid and alkali, emulsion, suspoemulsion and liquid metal.
Liquids, gas mixtures and liquids containing suspended solids can also be transported. The technical parameters of pump performance include flow rate, suction lift, lift, shaft power, water power, efficiency, etc.; according to different working principles, it can be divided into volumetric pumps, vane pumps and other types. Positive displacement pumps use the change in the volume of their working chambers to transfer energy; vane pumps use the interaction between rotating blades and water to transfer energy, and there are centrifugal pumps, axial flow pumps and mixed flow pumps.
Before starting the water pump, first fill the pump and the water inlet pipe with water. After the water pump is running, under the action of the centrifugal force generated by the high-speed rotation of the impeller, the water in the impeller channel is thrown to the surroundings and pressed into the volute, forming a vacuum at the impeller inlet. The water in the pool is sucked along the suction pipe under the external atmospheric pressure to supplement this space. Then the inhaled water is thrown out by the impeller through the volute and enters the outlet pipe. It can be seen that if the impeller of the centrifugal pump rotates continuously, it can continuously absorb and press water, and the water can be continuously lifted from a low place to a high place or far away. To sum up, the centrifugal pump is called a centrifugal pump because it lifts water to a high place under the action of the centrifugal force generated by the high-speed rotation of the impeller.
2. General characteristics of centrifugal pumps
(1) The flow direction of water along the centrifugal pump is sucked in along the axial direction of the impeller, and flows out perpendicular to the axial direction, that is, the direction of water flow in and out is 90° to each other.
(2) Since the centrifugal pump relies on the inlet of the impeller to form a vacuum to absorb water, it is necessary to pour water into the pump and the suction pipe before starting, or use a vacuum pump to exhaust the air to form a vacuum, and the pump casing and the suction pipe must be strictly sealed. There must be no air leakage, otherwise a vacuum will not be formed and water will not be absorbed.
(3) Since the impeller inlet cannot form an absolute vacuum, the suction height of the centrifugal pump cannot exceed 10 meters. In addition to the loss along the process caused by the water flowing through the suction pipeline, the actual allowable installation height (the height of the pump axis to the suction water surface) is much less than 10 m. If the installation is too high, it will not absorb water; in addition, because the atmospheric pressure in mountainous areas is lower than that in plains, when the same water pump is installed in mountainous areas, especially in high mountainous areas, its installation height should be lowered, otherwise it will not be able to absorb water.