What are the causes of lower outlet pressure of horizontal centrifugal pumps

What are the causes of lower outlet pressure of centrifugal pumps? One or more of the following reasons may cause the centrifugal pump outlet pressure to decrease.

• Motor reversal

Due to wiring reasons will lead to the motor's steering and the pump's actual requirements of the opposite direction, so that the general start to observe the pump's steering, if the steering is reversed, the motor should be on the terminals on any two wires can be exchanged.

• Working point to the large flow low head shift

In general, the centrifugal pump has a continuous downward performance curve, the flow rate with the reduction of head gradually become larger. In the course of operation, due to some reason resulting in a reduction in pump back pressure, the pump's operating point passively with the device curve to the low head of large flow point offset, which will cause a reduction in head, in fact, this is due to external factors such as device changes caused by the pump itself has no special relationship. At this time, as long as the pump back pressure increase, such as closing a little outlet valve can solve the problem.

• Speed reduction

Important factors affecting the pump head is the impeller OD and pump speed, in the case of other conditions remain unchanged, the pump head and speed of the quadratic proportional to the relationship between the visible speed of the impact on the head is very large, sometimes because of some external reasons to make the pump speed down, it will correspondingly reduce the head of the pump. At this time should check the speed of the pump, if indeed the speed is not enough, should check the reasons, reasonable solution.

• Inlet cavitation occurs

If the pump suction port pressure is too low, below the saturated vapour pressure of the pumped medium, cavitation will be formed. At this time, the inlet piping system should be checked for obstruction or whether the inlet valve opening is too small, or increase the level of the suction pool height.

• Internal leakage occurs

When the rotating part of the pump and the static part of the gap exceeds the design range, will lead to internal leakage, embodied in the pump discharge pressure drop, such as the impeller mouth ring clearance, multi-stage pump interstage clearance. At this time, the corresponding demolition inspection should be carried out, resulting in excessive clearance parts for repair or replacement.

• Impeller runner blockage

If the impeller part of the runner is blocked, it will affect the work of the impeller, resulting in a drop in outlet pressure. Therefore, it is necessary to dismantle the pump to check and remove the foreign matter. To prevent the problem from recurring, a filtering device can be added in front of the pump inlet if necessary. Centrifugal pump outlet pressure reduction is due to a number of reasons, the above several reasons please users one by one to check.