Basic knowledge of water pump 1

Water pump is to transport liquid or liquid pressurized machinery. It transmits the mechanical energy of the prime mover or other external energy to the liquid to increase the liquid energy. It is mainly used to transport liquids including water, oil, acid and alkali, emulsion, suspension emulsion and liquid metal.

Liquids, gas mixtures and liquids containing suspended solids can also be transported. The technical parameters of pump performance include flow, suction, head, 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 pump is the use of its working chamber volume changes to transfer energy; vane pump is the use of rotary blade and water interaction to transfer energy, centrifugal pump, axial flow pump and mixed flow pump type.

Centrifugal pump

1. Working principle of centrifugal pump

Before the pump is started, the pump and the inlet pipe are filled with water. After the pump is running, under the action of the centrifugal force generated by the high-speed rotation of the impeller, the water in the impeller runner is thrown around and pressed into the volute, and the impeller inlet forms a vacuum. The water in the pool is sucked along the suction pipe under the external atmospheric pressure to supplement this space. Then the sucked water is thrown out by the impeller through the volute and into the outlet pipe. It can be seen that if the centrifugal pump impeller rotates continuously, it can continuously absorb water and pressure water, and the water can be continuously raised from low to high or distant. In summary, the centrifugal pump is due to the centrifugal force generated by the high-speed rotation of the impeller, the water to the high place, so called centrifugal pump.

2. General characteristics of centrifugal pump

(1) the water along the flow direction of the centrifugal pump is along the axial suction of the impeller, perpendicular to the axial outflow, that is, the direction of the water flow into and out of each other 90 °.

(2) Since the centrifugal pump forms vacuum water absorption by the impeller inlet, it is necessary to pour water into the pump and the suction pipe before starting, or use a vacuum pump to exhaust air to form a vacuum, and the pump shell and the suction pipe must be strictly sealed, and no air leakage is allowed. Otherwise, vacuum cannot be formed and water cannot be sucked.

(3) Since the impeller inlet cannot form an absolute vacuum, the suction height of the centrifugal pump cannot exceed 10 meters, and the loss along the course caused by the water flow through the suction pipeline, the actual allowable installation height (the height of the pump axis from the suction water surface) is far less than 10 meters. If the installation is too high, it does not absorb water; in addition, because the mountainous area is lower than the plain atmospheric pressure, so the same pump in the mountainous area, especially in the mountainous area, the installation height should be reduced, otherwise it can not suck water.

axial flow pump

The working principle and characteristics of axial flow pump

1. The working principle of axial flow pump

The working principle of axial flow pump is different from that of centrifugal pump. It mainly uses the thrust generated by the high-speed rotation of the impeller to lift water. Axial flow pump blade rotation of the water generated by the lift, the water can be pushed from below to above.

The blades of an axial flow pump are generally immersed in a pool of water to be absorbed. Due to the high-speed rotation of the impeller, the lift generated by the blades will continuously push the water upward, so that the water will flow out along the outlet pipe. The impeller rotates continuously, and the water is continuously pressed to a high place.

2. General characteristics of axial flow pump

(1) the flow direction of water in the axial flow pump is along the axial suction and axial outflow of the impeller, so it is called axial flow pump.

(2) low lift (1~13 meters), large flow, high efficiency, suitable for plain, lake, river irrigation and drainage.

(3) no irrigation is required before starting, and the operation is simple.

mixed flow pump

1. Working principle of mixed flow pump

Because the impeller shape of the mixed-flow pump is between the centrifugal pump impeller and the axial-flow pump impeller, the working principle of the mixed-flow pump has both centrifugal force and lift. By the combined effect of the two, the water flows out of the impeller at a certain angle with the shaft, and the water is lifted to a high place through the volute chamber and the pipeline.

2. General characteristics of mixed flow pump

(1) Compared with centrifugal pumps, mixed-flow pumps have lower head and larger flow. Compared with axial-flow pumps, they have higher head and lower flow. It is suitable for irrigation and drainage in plain and lake areas.