There is air in the inlet pipe of the pump body

(1) Some users do not fully fill the water pump before starting it; Sometimes it appears that the filled water has overflowed from the vent hole, but the air has not been completely discharged by rotating the pump shaft, 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 downward slope of more than 0.5% in the opposite direction of the water flow, and the end connecting the water pump inlet should be the highest, not completely horizontal. If it is tilted upwards, air will remain in the inlet pipe, reducing the vacuum in the water pipe and pump, and affecting water absorption. water pump

(3) The packing of the water pump has been worn out or pressed too loose 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 extraction.

(4) Due to long-term potential underwater corrosion, holes appear on the pipe wall of the inlet pipe. After the water pump operates, the water surface continuously drops. When these holes are exposed to the water surface, air enters the inlet pipe through the holes.

(5) Cracks appear at the bend of the inlet pipe and small gaps appear at the connection between the inlet pipe and the water pump, which may allow air to enter the inlet pipe.

Pump speed too low Pipeline pump

(1) Human factors. A considerable number of users, due to damage to the original motor, randomly install another motor to drive, resulting in low flow rate, low head, and even inability to pump water.

(2) The drive belt is worn. Many large water pumps use belt transmission, but due to long-term use, the transmission belt is worn and loose, resulting in slipping and reducing the speed of the water pump.

(3) Improper installation. The center distance between the two pulleys is too small or the two shafts are not too parallel, the tight edge of the transmission belt is installed on top, resulting in a small wrap angle, incorrect calculation of the diameter of the two pulleys, and a large eccentricity between the two shafts of the water pump in the coupling drive, all of which can cause changes in the speed of the water pump.

(4) Mechanical failure of the centrifugal pump itself. The loosening of the fastening nut between the impeller and the pump shaft or the deformation and bending of the pump shaft can cause excessive displacement of the impeller, direct friction with the pump body, or damage to the bearings, which may reduce the speed of the water pump.

(5) Power machine maintenance is not recorded. The motor loses excitation due to the burning of the winding, and changes in winding turns, wire diameter, and wiring methods during maintenance, or factors that do not completely eliminate faults during maintenance, can also cause changes in the speed of the water pump.