A pump is a mechanical device that pumps energy liquids, converting the mechanical energy of the prime mover into the potential energy of the pumped liquid. Under the drive of power machinery, it can pump liquid from low to high or far, serving production.
A pump can pump water, oil, acid-base solutions, liquid metals, pulp, mud, and other substances. Generally speaking, the pump used for pumping water is called a water pump, also known as a water pump.
Water pumps are used for agricultural irrigation and drainage, improving the ability of agriculture to resist natural disasters, increasing production, ensuring yields, and providing material conditions for mechanization and water conservancy in agriculture. However, sometimes the water pump cannot pump out water during use. So, what are the reasons that affect the water pump's inability to pump out water? Let's talk about the reasons why the water pump is not producing water:
There is air in the inlet pipe and pump body
1.Before starting the water pump, it is not filled with enough water. Sometimes it appears that the water has overflowed from the vent hole, but the pump shaft has not been rotated to completely discharge the air, resulting in a small amount of air remaining in the inlet pipe or pump body.
2.The horizontal section of the inlet pipe in contact with the water pump should have a descending slope of at least 0.5% against the direction of water flow. The end connected to the inlet of the water pump should be the highest and not completely horizontal. If lifted upwards, air will remain in the inlet pipe, reducing the vacuum level in the water pipe and pump, and affecting water absorption.
3.The packing of the water pump has been worn out or compressed too loosely due to long-term use, causing a large amount of water to spray out from the gap between the packing and the pump shaft sleeve. As a result, external air enters the interior of the water pump through these gaps, affecting water lifting.
4.The inlet pipe has holes due to long-term potential underwater corrosion on the pipe wall. After the water pump works, the water level continuously drops. When these holes are exposed to the water surface, air enters the inlet pipe through the holes.
5.Cracks at the bend of the inlet pipe and small gaps at the connection between the inlet pipe and the water pump may allow air to enter the inlet pipe.
Low speed of water pump
1.Human factors. Some users, due to damage to the original motor, randomly installed another motor to drive it, resulting in low flow rate, low head, and even no water supply.
2.Mechanical failure of the water pump itself. Loosening of the fastening nut between the impeller and the pump shaft or deformation and bending of the pump shaft can cause excessive movement of the impeller, direct friction with the pump body, or damage to the bearings, all of which may reduce the speed of the water pump.
3.The maintenance of the power machine is not working properly. The motor loses magnetism due to winding burnout, and changes in winding turns, wire diameter, and wiring methods during maintenance, or factors that have not been completely eliminated during maintenance, can also cause changes in the speed of the water pump.
The suction stroke of the water pump is too large
Some water sources are deep, while others have flat terrain around them, ignoring the allowable suction range of the water pump, resulting in less or no water absorption. It should be noted that the vacuum degree that can be established at the suction port of a self-priming centrifugal pump is limited. The suction range of absolute vacuum is about 10 meters of water column height, and a water pump cannot establish absolute vacuum.
Moreover, excessive vacuum can cause the water inside the pump to vaporize, which is detrimental to the operation of the water pump. All centrifugal pumps have their maximum allowable suction range, typically between 3-8.5 meters. When installing a water pump, it is important not to only focus on convenience and simplicity.
Excessive resistance loss in the inlet and outlet pipes of water flow
Some users have measured that although the vertical distance from the reservoir or water tower to the water source surface is slightly less than the pump head, the amount of water they can lift is still small or they cannot lift water. The reason is often that the pipeline is too long, there are many bends in the water pipe, and the resistance loss of water flow in the pipeline is too large.
The reason is often that the pipeline is too long, there are many bends in the water pipe, and the resistance loss of water flow in the pipeline is too large. In general, the resistance of a 90 degree bend is greater than that of a 120 degree bend, with a head loss of about 0.5-1 meter per 90 degree bend. The resistance of a 20 meter pipe can cause a head loss of about 1 meter.
Through the above content, I believe everyone has gained a certain understanding of the problem of water pumps not being able to extract water. However, in addition to being unable to pump water, there are many other faults that can occur with the water pump, such as the pump being unable to start, the pump body vibrating violently or producing noise, excessive power consumption, and so on.
So, what should we do at this point? In this case, it is necessary to contact a professional company for maintenance work to avoid greater losses.
