Misunderstandings in the installation of vertical multi-stage centrifugal pumps
Common installation errors and related solutions for vertical multistage centrifugal pumps are:
1. There are many elbows on the water inlet pipe of the vertical multi-stage centrifugal pump.
If there are many elbows used in the water inlet pipeline, some water flow resistance will be increased. Moreover, the elbow should turn in the vertical direction and is not allowed to turn in the horizontal direction to avoid collecting air.
2. When installing the water inlet pipe, the horizontal section should be horizontal or upward.
This will cause air to collect in the water inlet pipe, reduce the vacuum degree of the water pipe and water pump, reduce the water suction lift of the water pump, and reduce the water output. The correct approach is: the horizontal section should be slightly tilted toward the water source, and should not be horizontal, let alone tilt upward.
3. The water inlet of the multi-stage centrifugal pump is directly connected to the elbow
This will cause the water to flow through the elbow and enter the impeller unevenly. When the diameter of the water inlet pipe is larger than the water inlet of the water pump, an eccentric reducer should be installed. The flat part of the eccentric reducer should be installed on the top, and the inclined part should be installed on the bottom. Otherwise, the air will accumulate, the water output will be reduced or the water will not be pumped out, and there will be impact sounds, etc. If the diameters of the water inlet pipe and the water inlet of the water pump are the same, a straight pipe should be added between the water inlet of the water pump and the elbow. The length of the straight pipe should not be less than 2 to 3 times the diameter of the water pipe.
4. The water outlet of the multi-stage centrifugal pump is above the normal water level of the outlet pool.
If the water outlet is above the normal water level of the outlet pool, although the pump head is increased, the flow rate is reduced. If the water outlet must be higher than the water level of the water outlet due to terrain conditions, an elbow and a short pipe should be installed at the pipe mouth to make the water pipe into a siphon type and reduce the height of the water outlet.
5. The orientation of the water inlet of the water inlet pipe is wrong.
①The distance between the water inlet of the water inlet pipe and the bottom and wall of the inlet pool is less than the diameter of the water inlet. If there is sediment and other dirt at the bottom of the pool, and 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 during pumping or suction of sediment and debris, blocking the water inlet.
② When the water inlet of the water inlet pipe is not deep enough, this will cause vortexes in the water surface around the water inlet pipe, affecting the water inlet and reducing the water output. The correct installation method is: the water entry depth of small and medium-sized water pumps shall not be less than 300~600mm, and the depth of large water pumps shall not be less than 600~1000mm.
6. When setting up the bottom valve, the bottom section of the water inlet pipe is not straight.
If installed in this way, the valve cannot close by itself, causing water leakage. The correct installation method is: the bottom section of the water inlet pipe equipped with a bottom valve should be straight. If it cannot be installed straight due to terrain conditions, the angle between the axis of the water pipe and the horizontal plane should be above 60°.
