1, unable to start.
Common faults in water pump maintenance. At this time, you should check the power supply first: at this time, you can see whether the connector connection is reliable; At the same time, it depends on whether the switch contacts are tight; See if the fuse is blown; Whether the three-phase power supply is equal. For example, if your power supply is found to be broken, poorly contacted, blown or out of phase, it should be repaired at this time. If it is not these problems, it may be the mechanical failure of the pump itself.
Common reasons are: the packing is too tight or the impeller and pump body are blocked by sundries; Corrosion of pump shaft, bearing and leakage reduction ring; The pump shaft is severely bent, etc. The solution is to loosen the filler and dredge the drainage channel; In this way, the pump body can be disassembled to remove impurities and rust; Remove the pump shaft for calibration or replace it with a new one.
2. The water pump is hot
Cause: It is possible that the bearing is damaged; It is also possible that the gap between the rolling bearing or the bracket cover is too small; So the pump shaft is bent or the two shafts are not concentric; If the tape is too tight; Lack of oil or poor oil quality; The balance hole on the impeller is blocked, and the impeller loses balance, which increases the thrust to one side. Solution: replace the bearing; Remove the rear cover and install a gasket between the bracket and the bearing seat.
3. Insufficient flow
Generally speaking, the power speed is not matched or the belt slips, resulting in low speed; The installation angle of axial flow pump blades is too small; Insufficient lift, too long pipeline or pipeline with right-angle bend; High suction range; Local blockage of bottom valve, pipeline and impeller or defect of impeller; The outlet pipe leaks badly.
Solution: Then you can consider restoring the rated speed, and remember to remove the grease on the belt and adjust the belt tightness; Adjust the blade angle to reduce the installation position of the pump, shorten the pipeline or change the curvature of the pipeline; Seal the air leakage of the water pump and compact the packing; Clear the blockage and replace the impeller; Replace the leakage reduction ring to stop the water leakage.
4, can't absorb water
Common faults in water pump maintenance, such as air in the pump body or gas accumulation in the water inlet pipe, or lax closing of the bottom valve, serious air leakage of vacuum pump packing, lax closing of gate valve or flap door, lead to poor water filling and diversion. Then its solution: first lift the water pressure, then fill the pump body with water, and then start the machine.
At the same time, remember to check whether the check valve is tight and whether the pipeline and joint are leaking. For example, if air leakage is found, apply lubricating oil or ready mixed paint to the joint after disassembly, and be sure to tighten the screws.
Check the oil seal ring of the water pump shaft. If it is seriously worn, please replace it with a new one. The pipeline leaks or leaks. Then it is possible that the nut was not tightened when you installed it. If the leakage is not serious, cement or cement slurry mixed with asphalt oil can be coated at the air leakage or water leakage place.
Extended data:
A water pump is a machine that transports or pressurizes liquid. It transfers the mechanical energy or other external energy of the prime mover to the liquid, which increases the energy of the liquid. Mainly used for conveying liquids, including water, oil, acid-base liquid, emulsion, suspension emulsion and liquid metal.
It can also transport liquids, gas mixtures and liquids containing suspended solids. The technical parameters of pump performance include flow, suction, lift, shaft power, hydraulic power and efficiency. According to different working principles, it can be divided into positive displacement pump and vane pump. The displacement pump uses the change of its working chamber volume to transfer energy; Vane pumps use the interaction between rotating blades and water to transfer energy, including centrifugal pumps, axial pumps and mixed-flow pumps.
General characteristics of centrifugal pump
(1) Water is sucked in the axial direction of the impeller along the flow direction 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) Because the centrifugal pump absorbs water by the inlet of the impeller, before starting, water must be injected into the pump and suction pipe, or air must be pumped by a vacuum pump to form a vacuum. The pump shell and suction pipe must be tightly sealed and cannot leak, otherwise there will be no vacuum and water cannot be absorbed.
(3) Because it is impossible to form an absolute vacuum at the inlet of the impeller, the suction height of the centrifugal pump cannot exceed10m, and the actual allowable installation height (the height between the axis of the pump and the suction surface) is much less than10m. 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 lowered when it is installed in mountainous areas, especially in mountainous areas, otherwise it will not be able to absorb water.
Working principle of axial flow pump
The working principle of axial flow pump is different from centrifugal pump, which mainly uses the thrust generated by high-speed rotation of impeller to lift water. The lift generated by the rotation of axial flow pump blades can push water from bottom to top.
The blades of axial-flow pump are generally 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. With the continuous rotation of the impeller, water is continuously pumped to high places.
The types, varieties and specifications of centrifugal pumps and their variant products are the most in agricultural pumps. There are single-stage single-suction centrifugal pump, single-stage double-suction centrifugal pump, multi-stage centrifugal pump, self-suction centrifugal pump, electric pump and diesel pump according to the way water flows into the impeller, the number of impellers, whether the pump body can self-suck and the size and type of supporting power.
1, single-stage single-suction centrifugal pump
The old pump models are BA and B single-stage single-suction centrifugal pumps. In 1980s, according to international standards and the actual situation of irrigation and drainage machinery, China upgraded and developed centrifugal pump products, and produced IB and IQ single-stage centrifugal pumps, which have been listed as national professional standards and industry standards.
Single-stage single-suction centrifugal pump is called single-stage single-suction centrifugal pump because water enters the impeller from one axial side and there is only one impeller. Compared with mixed-flow pump and axial-flow pump, it has the advantages of high lift, small 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, which meets the requirements of users for simple structure, light weight, low price, good performance and convenient matching. * * * There are 84 products, which are divided into 3 derivative series and 4 13 specifications.
(1) performance range: the cylinder diameter of the pump is 50 ~ 200mm, the flow rate is 12.5 ~ 400 m3/h, the lift is 8 ~ 125m, and the supporting power includes diesel engine direct connection, belt drive and motor direct connection, and the power is1./kloc-0.
(2) Structure: The light and small centrifugal pump is a shaft-suction single-stage single-suction suspension centrifugal pump. The back of the pump body is open, the outlet is located in the center, the back cover is press-fitted, 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.
Impeller is fully enclosed, and the transmission is divided into coupling transmission and belt transmission. Pump impeller steering: viewed from the inlet direction of the pump, the impeller steering is clockwise, and it is counterclockwise when the pump is directly connected with the diesel engine. 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
This is a single-stage double-suction centrifugal pump, and water flows out from both sides of the impeller. Because the pump cover and pump body are assembled with 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 water supply and drainage in factories, mines and cities.
Single-stage double-suction centrifugal pump has several models, such as S-type, Sh-type, SA-type and SLA-type. The difference between S-type pump and Sh-type pump is that S-type pump rotates clockwise from the driving end and Sh-type pump rotates counterclockwise. SLA is a vertical single-stage double-suction centrifugal pump.
The performance range of S-type pump is 160 ~ 18000 m3/h, the lift is 12 ~ 125m, the inlet diameter is 150 ~ 1400mm, and the rotating speed is 2950.
The performance range of (1)D pump is 6.3 ~ 720 m3/h, the lift is 16 ~ 600 m, and the inlet diameters are 50, 75, 100, 125, 150, 200mm.
(2) The structural D-type multistage centrifugal pump is horizontal multistage (2 ~ 12 stage), with single suction impeller and segmented pump body. When the first stage impeller is double suction, it is expressed by DS; When there are two speeds at the same time, the low speed is represented by DA; The multistage centrifugal pump used for boiler feed water is denoted by DG.
3. Self-priming centrifugal pump
Self-priming pump is a single-stage single-suction centrifugal pump, which is called self-priming centrifugal pump because of its special structure. Compared with ordinary centrifugal pumps, the pump body structure has obvious differences: first, the pump inlet position is improved, and sometimes a suction valve is installed; Secondly, the water outlet side is provided with a gas-water separation chamber.
Self-priming pump outside the pump is a self-priming device added to the pump, such as vacuum pump with vortex pump, water ring pump, jet pump and manual pump.
Compared with the ordinary centrifugal pump, the 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 the 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 the ordinary centrifugal pump with the same specification. Self-priming pumps are mostly used in light and small sprinkler irrigation units and pipeline irrigation units.
References:
Baidu encyclopedia-water pump