1、 There are many elbows on the inlet pipe of vertical multistage centrifugal pump

If more elbows are used on the inlet pipe, some flow resistance will be added. In addition, the elbow shall turn in the straight direction, and it is not allowed to turn in the horizontal direction to avoid gathering air.

2、 When the water inlet pipeline is installed, the horizontal section is horizontal or upward

In this way, air will be collected in the inlet pipe, the vacuum degree of the downcomer and the pump will be reduced, the suction head of the pump will be reduced, and the water output will be reduced. The correct approach is: the horizontal section should be slightly skewed towards the water source, not horizontal, and not upward.

3、 The water inlet of multistage centrifugal pump is directly connected with the elbow

This will cause uneven distribution of water flow into the impeller through the elbow. When the diameter of the water inlet pipe is larger than the water inlet of the pump, the reducer pipe should be installed. Some of the reducer planes need to be installed above, and some of the bevels need to be installed below. Otherwise, the air will be collected, the water output will be reduced or the water cannot be pumped, and there will be a sound of impact. If the diameter of the water inlet pipe and the water pump inlet is equal, a straight pipe shall be added between the water pump inlet and the elbow, and the length of the straight pipe shall not be less than 2~3 times of the water pipe diameter.

4、 The outlet pipe of multistage centrifugal pump is above the normal water level of the outlet pool

If the outlet is above the normal water level of the outlet pool, although the pump head is added, the flow is reduced. If it is necessary for the outlet to be higher than the water level of the outlet pool due to the terrain conditions, elbows and short pipes shall be installed at the pipe orifice to make the water pipe siphon and lower the outlet height.

5、 The water inlet position of the water inlet pipe is incorrect

① The distance between the inlet of the inlet pipe and the bottom and wall of the inlet tank is less than the diameter of the inlet. If there is sediment and other contaminants at the bottom of the pool, when the distance between the water inlet and the bottom of the pool is less than 1.5 times the diameter, it will cause poor water inflow or suck in sediment and debris during pumping, blocking the water inlet.