Water pump is a machine that delivers or pressurizes a liquid. It transfers the mechanical energy of the prime mover or other external energy to the liquid, increasing the energy of the liquid, mainly for transporting liquids including water, oil, acid and alkali, emulsion, suspoemulsion and liquid metal.
Liquids, gas mixtures, and liquids containing suspended solids can also be delivered. The technical parameters of the pump performance include flow, suction stroke, lift, shaft power, water power, efficiency, etc.; according to different working principles, it can be divided into volume pump, vane pump and other types. The volumetric pump uses its change in the volume of the working chamber to transfer energy. The vane pump uses the interaction of the rotating blades and water to transfer energy. There are centrifugal pump, axial flow pump and mixed flow pump.
Centrifugal pump
1. Working principle of the centrifugal pump
Before the pump starts, the pump and the inlet pipe are filled with water. After the pump is running, under the centrifugal force generated by the high-speed rotation of the impeller, the water in the impeller flow channel is pushed to the periphery, pressed into the volute, and the impeller inlet forms a vacuum. The water in the pool is inhaled along the suction pipe under external atmospheric pressure to supplement this space. The water that is inhaled is then pumped out of the volute by the impeller into the outlet pipe. It can be seen that if the centrifugal pump impeller rotates continuously, it can continuously absorb water and press water, and the water can be continuously raised from a low place to a high place or a distant place. In summary, the centrifugal pump is called the centrifugal pump because the centrifugal force generated by the high-speed rotation of the impeller raises the water to a high position.
2, the general characteristics of the centrifugal pump
(1) The direction of water flowing along the centrifugal pump is sucked in the axial direction of the impeller, and flows out perpendicularly to the axial direction, that is, the direction of the inflow and outflow flows at 90° to each other.
(2) Since the centrifugal pump forms vacuum suction through the inlet of the impeller, it is necessary to inject water into the pump and the suction pipe before starting, or pumping with a vacuum pump to discharge air to form a vacuum, and the pump casing and the suction pipe must be tightly sealed. Do not leak, otherwise it will not form a vacuum, it will not be able to absorb water.
(3) Since the impeller inlet cannot form an absolute vacuum, the water absorption height of the centrifugal pump should not exceed 10 meters, plus the loss of water flowing through the suction pipe, the actual allowable installation height (the height of the pump axis from the suction surface) is much smaller than 10 m. If the installation is too high, it will not absorb water; in addition, because the mountain area is lower than the plain atmospheric pressure, the installation height of the same pump should be reduced when installing in the mountainous area, especially in the high mountainous area, otherwise it will not be able to absorb water.
Axial flow pump
The working principle and characteristics of axial flow pump
1. Working principle of axial flow pump
The axial flow pump and the centrifugal pump work differently, and it mainly uses the thrust generated by the high-speed rotation of the impeller to lift water. The lift generated by the axial pump when it rotates can push the water from below to the top.
The blades of the axial flow pump are typically submerged in a pool of water source. Due to the high-speed rotation of the impeller, under the lifting force generated by the blade, the water is continuously pushed upward, so that the water flows out along the outlet pipe. As the impeller rotates continuously, 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 sucked in the axial direction of the impeller and flows out axially, so it is called an axial flow pump.
(2) Low head (1 to 13 meters), large flow, high efficiency, suitable for drainage in plains, lakes and rivers.
(3) No need to fill water before starting, the operation is simple.
Mixed flow pump
1. Working principle of mixed flow pump
Since the shape of the impeller 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 action of the two, the water flows out of the impeller at a certain angle with the shaft. Lift the water up through the volute chamber and piping.
2, the general characteristics of mixed flow pump
(1) Compared with the centrifugal pump, the mixed flow pump has a lower lift and a larger flow rate. Compared with the axial flow pump, the lift is higher and the flow rate is lower. Applicable to irrigation and drainage in plains and lakes.
(2) The water is sucked and discharged at a certain angle to the impeller shaft along the flow direction of the mixed flow pump, so it is also called a diagonal flow pump.
Pumps have different uses, different liquid media, different flow rates, and different lift ranges. Therefore, its structural form is of course different, and the materials are different. In summary, it can be roughly divided into:
1. Urban water supply 2, sewage system 3, civil engineering, building system 4, agricultural water conservancy system 5, power station system
6. Chemical system 7. Petroleum industry system 8. Mining metallurgical system 9. Light industrial system 10, ship system
