Centrifugal pump
1. Working principle of centrifugal pump
Before the water pump starts, the pump and the water inlet pipe are filled with water. After the water pump runs, 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 replenish this space. Then the sucked water is thrown out by the impeller and enters the outlet pipe through the volute. It can be seen that if the impeller of centrifugal pump keeps rotating, it can continuously absorb and press water, and the water can be continuously lifted from low to high or far away. To sum up, centrifugal pump is called centrifugal pump because of the centrifugal force generated by the high-speed rotation of impeller, which lifts water to a high place.
2. General characteristics of centrifugal pump
(1) Water is sucked in along the axial direction of the impeller along the flow direction of centrifugal pump, and flows out perpendicular to the axial direction, that is, the inlet and outlet water directions are at 9 degrees to each other.
(2) Because the centrifugal pump sucks water by the inlet of the impeller, water must be injected into the pump and the suction pipe before starting, or pumped by a vacuum pump to exhaust air to form a vacuum, and the pump shell and suction pipe must be strictly sealed to avoid air leakage, otherwise it will not form a vacuum, and water will not be sucked.
(3) Because it is impossible to form an absolute vacuum at the inlet of the impeller, the suction height of the centrifugal pump should not exceed 1m, and the actual allowable installation height (the height between the axis of the pump and the suction surface) is much less than 1m. 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 plain areas, the installation height of the same pump should be reduced when it is installed in mountainous areas, especially in high mountainous areas, otherwise it can't suck water.
axial flow pump
working principle and characteristics of axial flow pump
1. working principle of axial flow pump
the working principle of axial flow pump is different from that of centrifugal pump, which mainly uses the thrust generated by the high-speed rotation of impeller to lift water. The lift generated by the rotation of axial flow pump blades can push water from below to above.
generally, the blades of axial flow pumps are immersed in the pool of the sucked water source. Due to the high-speed rotation of the impeller, under the action of the lift generated by the blades, the water is continuously pushed upward, so that the water flows out along the water outlet pipe. As the impeller rotates continuously, water is continuously pumped to a high place.
Mixed-flow pump
1. Working principle of Mixed-flow pump
Because the impeller shape of Mixed-flow pump is between centrifugal pump impeller and axial pump impeller, the working principle of Mixed-flow pump has both centrifugal force and lift force. Under the combined action of the two, 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 pipeline.
2. General characteristics of mixed-flow pump
(1) Compared with centrifugal pump, mixed-flow pump has lower lift and larger flow, while compared with axial pump, it has higher lift and lower flow. Suitable for irrigation and drainage in plain and lake areas.
(2) Water is sucked in and out at a certain angle with the impeller shaft along the flow direction of mixed-flow pump, so it is also called diagonal flow pump.
commonly used agricultural pumps
centrifugal pumps
centrifugal pump models, specifications and their variant products are the most in agricultural pumps. According to the way water flows into the impeller, the number of impellers, whether the pump body can self-suck, and the size and variety of supporting power, there are single-stage single-suction centrifugal pump, single-stage double-suction centrifugal pump, multi-stage centrifugal pump, self-suction centrifugal pump, motor pump and diesel pump.
1. Single-stage single-suction centrifugal pump
The old pump models include BA and B single-stage single-suction centrifugal pumps. In the 198s, according to international standards and the actual situation of irrigation and drainage machinery, China upgraded and developed centrifugal pump products, and produced series of IB and IQ single-stage centrifugal pumps, which have been listed as national professional standards and industry standards.
a single-stage single-suction centrifugal pump is called a single-stage single-suction centrifugal pump, because water enters the impeller from one side in the axial direction, and there is only one impeller. Compared with mixed-flow pump and axial-flow pump, it has higher lift, smaller flow, simple structure and convenient use.
IQ single-stage single-suction centrifugal pump (also known as light and small centrifugal pump) is designed according to China's national conditions and meets the requirements of users for simple structure, light weight, low price, good performance and convenient matching. * * * There are 84 products, divided into 3 derivative series and 413 specifications and models.
(1) performance range: the pump bore is 5 ~ 2mm, the flow rate is 12.5 ~ 4m3/h, the lift is 8 ~ 15m, and the supporting power is diesel direct connection, belt drive and motor direct connection, with the power of 1.1 ~ 11kW and the rotating speed of 1,45 ~ 2,9rpm.
(2) structural type light and small centrifugal pump is axial suction single-stage single-suction suspension centrifugal pump. The pump body opens at the back, the outlet is located at the center, the back cover is press-embedded, the bearing body is directly connected with the pump body, the pump foot is located below the pump body, the bearing is lubricated with butter, and the shaft seal is divided into three types: soft packing, mechanical seal and rubber oil seal. Impellers are all closed, and the transmission is divided into coupling transmission and belt transmission. Pump impeller steering: when viewed from the inlet direction of the pump, the impeller steering is clockwise, and when the pump is directly connected with the diesel engine, it is counterclockwise. A manual pump can be installed at the pump outlet, and the bottom valve can be removed to reduce the hydraulic loss and make the pump self-priming.
2. Single-stage double-suction centrifugal pump
It is a single-stage double-suction centrifugal pump that feeds water from both sides of the impeller. Because the pump cover and pump body are assembled by horizontal joints, it is also called horizontal open centrifugal pump. Compared with single-stage single-suction centrifugal pump, it has high efficiency, large flow and high lift. However, it is bulky and bulky, and is generally used for fixed operations. It is suitable for medium-sized irrigation areas in hills and plateaus, as well as factories, mines, urban water supply and drainage, etc.
there are several types of single-stage double-suction centrifugal pumps, such as S-type, Sh-type, SA-type and SLA-type. The difference between S-type and Sh-type is that the S-type pump rotates clockwise and the Sh-type pump rotates counterclockwise from the driving end. SLA is a vertical single-stage double-suction centrifugal pump.
the performance range of S-type pump is 16 ~ 18,m3/h, the lift is 12 ~ 15m, the inlet diameter is 15 ~ 1,4mm, and the rotating speed is 295, 145, 97, 73, 585, 485 and 36 rpm.
(1) The performance range of D-type pump is 6.3 ~ 72 m3/h, the lift is 16 ~ 6 m, and the inlet diameter is 5, 75, 1, 125, 15, 2mm, among which the 5 ~ 125mm pump is a high-speed pump with 295 rpm and 15 ~ 2mm.
(2) Structure Type D multistage centrifugal pump is horizontal multistage (2 ~ 12 stages), with single suction impeller and segmented pump body. When the first stage impeller is double suction, it is represented by DS; when there are two rotating speeds at the same time, the low speed is represented by DA; and the multistage centrifugal pump used for boiler feed water is represented by DG.
3. Self-priming centrifugal pump
Self-priming pump is a single-stage single-suction centrifugal pump that produces self-priming effect by its own special structure, which is called self-priming centrifugal pump. Compared with ordinary centrifugal pump, there are significant differences in pump body structure: first, the pump inlet position is improved, and sometimes a suction valve is installed; Secondly, a gas-water separation chamber is arranged on the water outlet side.
Self-priming pump outside the pump is a self-priming device added to the pump, such as vacuum pump with vortex pump, water ring, jet pump and manual pump.
compared with ordinary centrifugal pump, self-priming pump has the advantages of compact structure and simple operation, which not only saves the trouble of pouring a lot of water before starting, but also saves the low valve of water inlet pipe, reduces the water inlet resistance and increases the water output of the pump, but the efficiency is 3% ~ 5% lower than that of ordinary centrifugal pump with the same specification. Self-priming pumps are mostly used in light and small sprinkler irrigation units and pipeline irrigation units.
submersible pump
magnetic suspension submersible pump has achieved a major breakthrough in the field of submersible pumps in the world, and effectively solved various disadvantages of traditional submersible pumps, such as low conversion efficiency, high power consumption, limited lift, fragile bearings, frequent maintenance and so on. Widely used in water supply and drainage of industrial and mining enterprises, farmland irrigation and water supply in plateau and mountainous areas.
magnetic suspension submersible pump has changed the manufacturing process of submersible pump with unique patented technology, and the conversion efficiency has reached a shocking new level, creating huge energy-saving and consumption-reducing benefits.
The magnetic suspension submersible pump has solved the axial force problem that restricts the development of the submersible pump field in the world, and the lift of the submersible pump has been improved in a breakthrough way, filling the market gap of ultra-high lift (single machine lift is designed to thousands of meters) and ultra-large flow (high load) submersible pumps; The curves of lift and flow tend to be flat. Its conversion efficiency and the highest lift of a single machine are in the leading position in the world.
magnetic levitation submersible pump is a new generation of submersible pump, which realizes vertical shaft magnetic levitation (keeping high efficiency under different working conditions), does not wear, prolongs the service time and maintenance period by several times, saves frequent regular maintenance work, can run for tens of thousands of hours continuously, and saves maintenance and repair costs.
the magnetic suspension submersible pump has passed the national laboratory and the Shandong pump product quality inspection center. The test data prove that the conversion efficiency of magnetic suspension submersible pump is higher than that of traditional submersible pump. Combined with the experimental data and field comparison, the user's use situation further proves its characteristics of high efficiency, energy saving, world-leading conversion efficiency, world-leading single-machine lift, high load, large flow, maintenance-free and long life.
Using polymer composite material
During the operation of the water pump, the water flowing in the pump is affected by its friction with the runner and the surface of the pump impeller and the viscosity of the water body, and the energy consumed by the pump is mainly used to resist the flowing friction and eddy current resistance on the water surface. The energy consumed by water in the process of flowing (head loss) is used to overcome the internal friction and the friction between water and equipment interface. If the surface of pump and impeller is smooth (this surface is called hydraulic smooth surface), the surface resistance is small. The energy consumption is low. Polymer composite materials are sprayed on the flow surface and impeller of the pump to form a hydraulic smooth surface. The surface smoothness of the ultra-smooth surface coating is 2 times that of polished stainless steel. This extremely smooth surface reduces the stratification of the fluid in the pump, thus reducing the internal turbulence of the pump, reducing the volume loss and hydraulic loss in the pump and reducing the power consumption. The purpose of reducing the resistance loss of water flow is achieved, thus improving the hydraulic efficiency of the pump, and at the same time improving the mechanical efficiency and volumetric efficiency to a certain extent. The compactness of the molecular structure of the coating can isolate the contact between air, water and the base material of the pump impeller, and minimize electrochemical corrosion and rust. In addition, the polymer composite material is a polymer with chemical corrosion resistance, which can improve the corrosion resistance of the pump and greatly enhance the erosion resistance and corrosion resistance of the pump.