Why can't the centrifugal pump pump water?

Time：2024/3/27 Source：PEARL PUMP Views：

Water Pump Air Inlet

1:The pump is not filled with water before starting.

2:The horizontal section of the water inlet pipe in contact with the pump should have a downward slope of more than 0.5% in the opposite direction of water flow. The end connecting to the pump inlet should be the lowest point and not completely horizontal. If it is raised upwards, air will remain in the water inlet pipe, reducing the vacuum in the pipe and pump, affecting suction.

3:The pump packing is worn out due to long-term use or the packing is too loose, 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 pump, affecting water lifting.

4:The water inlet pipe corrodes and develops holes after being submerged in water for a long time. As the pump operates, the water level continuously decreases. When these holes are exposed above the water surface, air enters the water inlet pipe through them.

5:Cracks occur at the bends of the water inlet pipe, and there are tiny gaps at the connection between the water inlet pipe and the pump, both of which may allow air to enter the water inlet pipe.

Low Pump Speed

1:Human factors. A considerable number of users randomly replace the original motor with another one, leading to consequences such as low flow rate, low head, or even inability to pump water.

2:Belt wear. Many large-scale pumps use belt drives. Due to long-term use, the belts may wear and become loose, resulting in slipping and reducing the pump's speed.

3:Improper installation. When the center distance between the two pulleys is too small or the two shafts are not parallel, and the belt is installed too tightly, causing a small included angle, miscalculation of the diameters of the two pulleys, or a large eccentricity of the pump's two shafts in the coupling transmission, it can lead to changes in the pump's speed.

4:Mechanical failures of the centrifugal pump itself. Loose fastening nuts between the impeller and the pump shaft or bending of the pump shaft, causing the impeller to shift excessively, resulting in friction with the pump body, or bearing damage, may all reduce the pump's speed.

5:Neglected maintenance of the power unit. Changes in the number of turns, wire diameter, and wiring method of the winding during motor repair due to burnt windings or demagnetization, or incomplete elimination of faults during maintenance, can also change the pump's speed.

Next：What are the three types of pump?

Pre：What is an industrial pump?