Reasons for The Decrease of Vertical Multistage Pump Outlet Pressure
The wrong way of wiring can cause the motor to turn in the opposite direction to the actual requirements of the pump. So it is need to inching the motor before normal operation to check the direction of the pump steering.
If the interval between the rotating part and the stationary part of the pump exceeds the design range, it will lead to internal leakage, such as the clearance between the impeller mouth ring and the inter-stage clearance of the multi-stage pump. At this time, the corresponding dismantling should be carried out to repair.
The important factors affecting the pump head are the impeller diameter and the speed. other conditions unchanged, The head of the pump is directly proportional to the second power of the speed under the other things being equal. The speed of the pump also may reduced by some external reasons, so the head of the pump will be correspondingly reduced.
If the pressure in the pump inlet is lower than the saturated vapor pressure of the pumping medium, cavitation will be formed. At this time should check whether the inlet pipeline system is blocked or the opening of the inlet valve is too small, or improve the liquid level height of the suction tank.
If the impeller part of the flow channel is blocked, it will affect the work of the impeller, resulting in a drop in outlet pressure. Therefore, it is necessary to remove the pump for inspection and removal of foreign bodies. In order to prevent the problem again and the cleanliness of the imported medium can not be guaranteed, the filter device can be installed before the pump is imported.
