self-priming pumpIt relies on the high-speed rotation of the impeller to create a low-pressure zone inside the stainless steel self-priming pump for water pumping, so the centrifugal pump must ensure that its inlet pipe does not leak, that is, to ensure that external air cannot enter the inlet pipe. Otherwise, it will not only affect the efficiency of pumping water, but also cause serious vibration and noise during pump operation.

In work, if the water pump has insufficient or no water output, the first thing to consider is whether there is air entering the inlet pipe due to sand holes, cracks, or loose joints, and observe it to find the inlet. Some defects are very subtle and difficult to detect with the naked eye, often resulting in laborious and time-consuming results.

Here are several simple and easy methods to check for pump inlet pipeline leaks.

(1) Duck Feather Method: Use a duck feather to approach the suspected intake point while the water pump is running, and observe the movement of the duck feather. Similarly, lit cigarettes can be operated in this way. Use the direction of duck feathers and smoke to assist in searching.

(2) Oil method: For difficult to identify intake points, a small amount of oil can be applied to the approximate intake area, and the area where the oil is quickly sucked away is the intake area.

Below are some measures to prevent the intake of self-priming pumps. If there are any shortcomings, please leave a message to supplement:

(1) The installation position should be as close to the water surface as possible to ensure that no air is sucked in when the water level drops.

(2) When installing the suction pipe, the horizontal inlet pipe should be slightly inclined downwards or installed horizontally towards the incoming water direction. No point on the inlet pipe should be higher than the water pump inlet, otherwise the air inside the pipe cannot be completely discharged.

(3) To prevent air leakage from the filling culvert. The tightness of the packing culvert should be appropriate. If it is too loose, the packing gland should be tightened; Damaged or ineffective fillers should be replaced in a timely manner; The blockage and heating of the water seal pipe at the filling area will cause air leakage in the filling area, and the water seal pipe should be cleaned.

(4) Before installing the inlet pipe connected by flanges, the flat surfaces where the two flanges are in contact should be cleaned, and a 3-5mm thick rubber pad should be added in the middle. The bolts should be tightened symmetrically and gradually in several stages.

(5) The bottom valve of the self-priming water pump should have sufficient submergence depth. The submergence depth from the valve plane should be 1.5~2 times the outer diameter of the bottom valve, at least 0.5m. If the submergence is too shallow, it is easy to form vortices, which can suck in air, cause cavitation, and damage the impeller and pump casing. If it is found that the inlet water level drops rapidly during the operation of the water pump, several wooden boards can be placed on the water surface to reduce vortices and prevent air from entering the pump casing.

(6) The pump body is equipped with a vent plug. To facilitate venting, water with the same thread size can be used instead of the vent plug. When venting, simply boil water.

(7) The vacuum degree at the suction port is limited. If the vacuum is too large, it can easily cause water vaporization in the pump, which is not conducive to the operation of the self-priming water pump. Therefore, each suction pump has its own maximum allowable suction range, generally between 3-8.5m, and should be controlled within this range during installation.

(8) Pay attention to exhaust. Before starting, sufficient water intake should be added to eliminate the air inside the self-priming pump; Regularly open the vent plug on the pump cover to eliminate the accumulated air inside.