Analysis of the reasons why stainless steel centrifugal pumps cannot lift water
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Stainless steel centrifugal pumps are the most widely used type of water pump in agriculture due to their simple structure, ease of use and maintenance, and high efficiency. However, they can be a source of frustration as they sometimes fail to lift water. Here is an analysis of the reasons why the centrifugal pump fails to lift water. There is air in the inlet pipe of the stainless steel centrifugal pump and inside the pump: (1) Some users fail to fill the pump with enough water before starting it ； Sometimes it seems that the water poured in has overflowed through the vent hole, but the pump shaft was not rotated to completely expel the air, resulting in some air remaining in the inlet pipe or within the pump body. (2) The horizontal section of the inlet pipe in contact with the water pump should have a slope of more than 0.5% in the direction opposite to the flow of water; the end connected to the water pump’s inlet should be at the highest point, and it should not be completely horizontal. If it tilts upward, air will remain in the water inlet pipe, reducing the vacuum level in the pipe and pump and affecting water suction. (3) The packing of the centrifugal pump has worn out due to long-term use, or it is too loose, resulting in a large amount of water spraying out from the gap between the packing and the pump shaft sleeve. As a consequence, external air enters the interior of the water pump through these gaps, affecting its ability to lift water. (4) Due to being submerged underwater for a long time, the pipe walls of the water inlet pipe corroded and developed holes; as the water level dropped continuously after the pump started operating, air entered the water inlet pipe through these holes once they came above the water surface. (5) Cracks at the bends of the water inlet pipe, as well as small gaps at the connection between the water inlet pipe and the water pump, can both allow air to enter the water inlet pipe. For more information, please visit the China Pump Industry Network
(1) Insufficient filling pump operation (or gas not fully exhausted from the pump). The solution is to refill the pump. (2) The pump is turned in the wrong direction. The solution is to check the rotation direction. (3) The pump speed is too low. The solution is to check the speed and increase it. (4) The filter screen is clogged, and the bottom valve is not functioning properly. The solution is to check the filter screen and remove any debris. (5) The suction height is too high, or a vacuum has formed in the liquid suction tank. The solution is to reduce the suction height ； Check the suction tank pressure.
Quite comprehensive. The main reason for being unable to draw in water is to check for air in the pipes; if a new pump can draw in water at first but stops doing so after some time, then it’s necessary to check for wear and tear on certain components.
It’s not just stainless steel pumps that experience this issue.
What the original poster meant is adapting to all centrifugal pumps :)
Isn’t this exactly the analysis of the reasons why a centrifugal pump cannot deliver the required flow rate?