Inlet pipe and pump body with air:
1. Some users before the start of the pump does not fill enough water, sometimes looks like the water has been poured from the vent overflow, but did not turn the pump shaft to the air completely discharged, resulting in a little air left in the water pipe or pump body.
2. And
self-priming centrifugal pumps are in contact with the water level of the pipe segment against the flow direction of the application of more than 0.5% of the decline in the slope, connect one end of the pump inlet of the highest, not to complete the level. If the upward tilt, will be retained within the inlet air, reduce water pipes and pumps in the vacuum, the impact of water.
3.
Self suction pump filler used for long-term wear and tear or packing has been pressed too loose, causing a lot of water ejected from the shaft sleeve and fill the gap, the result is the outside air into the pump from the gap of internal, affecting the water extraction.
4. The water pipe due to the long-term potential of water, pipe wall corrosion appear holes,
water pump works, the water continued to decline, when these holes exposed, the air from the hole into the water inlet pipe.
5. The water pipe bend pipe cracks, water inlet pipe and the water pump connection at the small gap, it is possible to make the air into the water inlet pipe.
Pump speed is too low:
1. Human factors. There is a considerable part of the user damage because of original motor, free with the other a motor driven resulting in a small flow and low lift even of Sheung Shui consequences.
2. Transmission belt wear. There are many large centrifugal pump with a mass, due to prolonged use, transmission belt wear and relaxation, the slipping phenomenon, so as to reduce the pump speed.
3. Improper installation. Belt wheel center distance is not too small or two axes parallel to the belt tight over the installation of the above, resulting in the wrap angle is too small, and the diameter of the belt wheel are calculation errors and the pump shaft coupling drive axis eccentricity of the two large, are caused by variation of the pump speed.
4. Self suction pump mechanical failure itself. Impeller and pump shaft fastening nut loose or pump shaft deformation and bending, resulting in multi impeller, direct friction with the pump body, or bearing damage, it is possible to reduce the pump speed.
5. Power machine repair problems. Motor due to the winding burn, and loss of magnetism, maintenance of the winding turns, wire diameter, wiring method changes, or the failure of the maintenance of the fault is not completely eliminated factors will make the pump speed change.
Suction process is too large:
Some of the water is deep, some of the surrounding terrain is relatively flat, while ignoring the pump allows suction process, resulting in less water absorption or not the result of water suction. To know that the vacuum degree of the pump suction mouth is limited, the absolute vacuum suction process is about 10 meters high water column, while the pump can not establish an absolute vacuum. And a large vacuum, easy to make the pump water vapor, the pump work. Therefore, the centrifugal pump has its maximum allowable suction process, generally between 8.5 - 3 meters.
Some users after measurement, although the water reservoir or water tower to the vertical distance from the water surface is slightly less than the pump head, but a small amount of water or Sheung Shui. The reason is that the pipe is too long, the water pipe bends more, the water flow in the pipeline resistance loss is too large. The reason is that the pipe is too long, the water pipe bends more, the water flow in the pipeline resistance loss is too large. Under normal circumstances 90 degrees bend than 120 degrees, the resistance is large, every 90 degrees bend head loss of about 0.5-1 meters, meters per 20 meters of resistance can make the head loss of about 1 meters. In addition, some users are free to pump inlet, outlet pipe diameter, which has a certain impact on the head.
The impact of other factors
1. Valve open. Is usually set aside a long time due to water pump, valve gasket is stuck, no washer valve may be rust.
2. Filter mesh bottom valve is blocked; or potential water valve at the end of the sludge layer caused by the blockage of the strainer.
3. Impeller wear is serious. Impeller blades have been worn for a long time, which affects the performance of the pump.
4. The gate valve can be a fault or blockage will cause the flow to reduce or even draw no water.
5. The leakage of the export pipeline will also affect the water pumping capacity of self priming pump.
