Centrifugal pump 1. The working principle of centrifugal pump. Before starting the pump, fill the pump and the inlet pipe with water. After the pump runs, under the action of the centrifugal force generated by the high-speed rotation of the impeller, the water in the impeller channel is thrown around, pressing Into the volute, the impeller inlet forms a vacuum, and 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 continuously rise from low to high or far. In summary, the centrifugal pump is called 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. The general characteristics of centrifugal pumps (1) Water is sucked in along the axial direction of the impeller along the direction of flow of the centrifugal pump, and flows out perpendicular to the axial direction, that is, the direction of water flow in and out is 90°. (2) Since the centrifugal pump forms a vacuum suction by the impeller inlet, it is necessary to pour water into the pump and suction pipe before starting, or use a vacuum pump to exhaust air to form a vacuum, and the pump casing and suction pipe must be strictly sealed. There must be no air leakage, otherwise a vacuum will not be formed and the water will not be sucked up. (3) Since it is impossible to form an absolute vacuum at the impeller inlet, the suction height of the centrifugal pump cannot exceed 10 meters, plus the loss along the way caused by the water flowing through the suction pipeline, the actual allowable installation height (the height of the pump axis from the suction surface) is much smaller than 10 meters. If the installation is too high, no water will be absorbed; in addition, because the atmospheric pressure is lower in mountainous areas than in plains, the installation height of the same pump in mountainous areas, especially in high mountainous areas, should be lowered, otherwise it cannot suck up water. The working principle and characteristics of the axial flow pump 1. The working principle of the axial flow pump The working principle of the axial flow pump is different from the centrifugal pump. It mainly uses the thrust generated by the high-speed rotation of the impeller to lift water. The lift generated by the blades of the axial flow pump against the water can push the water from below to above. The blades of the axial flow pump are generally immersed in the pool of the suction 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 upwards, causing the water to 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 pumps (1) The flow direction of water in the axial flow pump is suction and outflow along the axial direction of the impeller, so it is called axial flow pump. (2) Low head (1-13 meters), large flow, high efficiency, suitable for irrigation and drainage in plains, lakes and rivers. (3) No need to fill water before starting, easy operation. Mixed flow pump 1. Working principle of mixed flow pump Because the impeller shape of mixed flow pump is between the impeller of centrifugal pump and the impeller of axial flow pump, the working principle of mixed flow pump has both centrifugal force and lift force. Then it flows out of the impeller at a certain angle with the shaft, and lifts the water to a higher place through the volute chamber and pipeline. 2. General characteristics of mixed-flow pumps (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. Suitable for irrigation and drainage of plains and lake areas. (2) Water is sucked and discharged at a certain angle with the impeller shaft along the flow direction of the mixed flow pump, so it is also called a diagonal flow pump. Commonly used agricultural pumps, centrifugal pumps, centrifugal pump models, specifications and variants are the most in agricultural pumps. According to the way the water flows into the impeller, how many impellers, whether the pump body can self-prime, the size and power of the supporting power, etc., centrifugal pumps include single-stage single-suction centrifugal pumps, single-stage double-suction centrifugal pumps, multi-stage centrifugal pumps, and self-priming centrifugal pumps. Pumps, motor pumps and diesel engine pumps, etc. 1. The old pump models of single-stage single-suction centrifugal pumps are ba and b-type single-stage single-suction centrifugal pumps. In the 1980s, my country carried out the research and development of the centrifugal pump products according to international standards and the actual situation of drainage and irrigation machinery, and produced ib Type, iq type single-stage centrifugal pump series products have been listed as national professional standards and industry standards. Single-stage single-suction centrifugal pump, water enters the impeller from one side in the axial direction, and there is only one impeller, so it is called single-stage single-suction centrifugal pump. Its characteristics are that compared with mixed flow pumps and axial flow pumps, it has higher head, smaller flow, simple structure and convenient use. The iq single-stage single-suction centrifugal pump (also known as light and small centrifugal pump) is designed according to the national conditions and meets the user's requirements for simple structure, light weight, low price, good performance and convenient matching. There are 84 products in total. 3 derivative series, 413 specifications and models. (1) Performance range: The pump has a diameter of 50~200mm, a flow rate of 12.5~400 cubic meters per hour, a head of 8~125 meters, and the supporting power includes direct diesel engine, belt drive, direct motor connection, power 1.1~110kw, speed 1450~ 2900 rpm. (2) The structure type light and small centrifugal pump is an axial suction single-stage single-suction suspension centrifugal pump. The pump body is opened behind the door, the outlet is located in the center upwards, the rear cover is press-fitted, the bearing body is directly connected to the pump body, and the pump foot Located under 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. The impellers are all closed, and the transmission is divided into coupling transmission and belt transmission. Pump impeller steering: Seen from the pump inlet direction, the impeller steering is clockwise, when the pump is directly connected to the diesel engine, it is counterclockwise. The pump outlet can be equipped with a manual pump, and the bottom valve can be removed to reduce 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 a horizontal split centrifugal pump. Compared with single-stage single-suction centrifugal pump, it has high efficiency, large flow and higher head. But it is large and heavy, and is generally used for fixed operations. It is suitable for medium-sized irrigation areas on hills and plateaus, as well as for factories, mines, and urban water supply and drainage. Single-stage double-suction centrifugal pumps have s-type, sh-type, sa-type and sla-type models. The difference between s-type and sh-type is that from the driving end, s-type pumps rotate in a clockwise direction, and sh-types are counterclockwise. Direction rotation. The sla type is a vertical single-stage double-suction centrifugal pump. The performance range of s-type pump is 160~18000 cubic meters per hour, head 12~125 meters, inlet diameter 150~1400mm, speed 2950, ​​1450, 970, 730, 585, 485, 360 rpm. (1) The performance range of type d pump is flow rate 6.3~720 cubic meters/hour, head 16~600 meters, water inlet diameter: 50, 75, 100, 125, 150, 200 mm, of which 50~125 mm pump type is high speed 2950 rpm, 150~200mm pump type speed is 1480 rpm. (2) Structure type d-type multistage centrifugal pump is horizontal multistage (2~12 stages), the impeller is single suction, and the pump body is segmented. When the first-stage impeller is double-suction, it is represented by ds. When two speeds are specified at the same time, the low speed is represented by da. The multi-stage centrifugal pump used for boiler feed water is represented by dg. 3. Self-priming centrifugal pump The self-priming pump is a single-stage single-suction centrifugal pump that produces self-priming by the special structure of the pump itself, called a self-priming centrifugal pump. Compared with ordinary centrifugal pumps, there are significant differences in the structure of the pump body: first, the pump inlet position is increased, and sometimes a suction valve is installed; second, a gas-water separation chamber is set on the water outlet side. The self-priming pump outside the pump is a self-priming device added to the pump, such as a vortex pump, a water ring vacuum pump, a jet pump, and a hand pump. Compared with ordinary centrifugal pumps, self-priming pumps have compact structure and simple operation. It not only saves the trouble of filling a large amount of water before starting, but also eliminates the low valve of the 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 pumps of the same specification. Self-priming pumps are mostly used in light and small sprinkler irrigation units and pipeline irrigation units. The submersible electric pump magnetic levitation submersible electric pump has achieved a major breakthrough in the field of submersible electric pumps in the world, and effectively solved the shortcomings of traditional submersible electric pumps: such as low conversion efficiency, high power consumption, limited lift, easy damage to bearings, and frequent maintenance Wait. It is widely used in water supply and drainage of industrial and mining enterprises, farmland irrigation and water supply in plateau and mountainous areas. The magnetic levitation submersible electric pump has changed the manufacturing process of the submersible electric pump with its unique patented technology, and the conversion efficiency has reached a shocking new level, creating a huge energy saving and consumption reduction benefit. The magnetic levitation submersible electric pump solves the problem of axial force that restricts the development of the world's submersible electric pump field. The head of the submersible electric pump has a breakthrough improvement, which fills in the ultra-high head (single unit head design to thousands of meters) and super large flow (high load capacity) ) The market for submersible electric pumps is blank; the head and flow curves tend to be flat. Its conversion efficiency and the highest head of a single machine are in the leading position in the world. The magnetic levitation submersible electric pump is a new generation of submersible electric pump, which realizes the vertical shaft magnetic levitation (maintains high efficiency under different working conditions), does not wear, and extends the service time and maintenance cycle by several times, eliminating frequent regular maintenance work, and can operate continuously Tens of thousands of hours save maintenance and overhaul costs. The magnetic levitation submersible electric pump has passed the inspection of the national laboratory and the Shandong Pump Product Quality Inspection Center. The test data proves that the conversion efficiency of the magnetic levitation submersible electric pump exceeds that of the traditional submersible electric pump. The user's usage combined with the experimental data and the comparison in the field further proves its high efficiency and energy saving, the world's leading conversion efficiency, the world's leading stand-alone head, and high load capacity, super large flow, Maintenance-free and long-life features! The submersible sewage pump uses polymer composite materials. During the pumping process, the water flowing in the pump is affected by the friction with the flow channel and the surface of the pump impeller and the viscosity of the water body. The energy consumed by the pump Mainly used to resist the flow friction and eddy resistance of the water surface. The energy consumed by water (head loss) in the flow of water is used to overcome the internal friction and the friction between the water and the equipment interface. If the surface of the pump and impeller is smooth (this surface is called hydraulic smooth surface), the surface resistance is small. The energy consumption is small. The polymer composite material is sprayed on the flow surface and the impeller of the pump to form a hydraulically smooth surface. The surface finish of the super smooth surface coating is 20 times that of the polished stainless steel. This extremely smooth surface reduces The stratification of the fluid in the pump reduces the turbulence inside the pump, reduces the volume loss and hydraulic loss in the pump, and reduces power consumption. To achieve the purpose of reducing the water flow resistance loss, thereby improving the hydraulic efficiency of the water pump, and at the same time, it can also improve the mechanical efficiency and volumetric efficiency to a certain extent. The compactness of the molecular structure of the coating can isolate the contact of air, water and other media with the base material of the pump impeller, and minimize electrochemical corrosion and rust. In addition, the high-molecular composite material is a high-molecular polymer, which has chemical corrosion resistance, can improve the corrosion resistance of the pump, and can greatly enhance the pump's resistance to erosion and corrosion.