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Why does a Split Casing Pump Run Idling? What's the Harm?

September 15,2023

Idling of a  split casing pump  is very harmful, may cause cavitation or damage to the mechanical seal and other problems. Today, we’ll explore the causes and hazards of it.


Reason for Idling

The inlet medium of the pump is insufficient or the water inlet pressure is not enough, or the water inlet pipe is blocked, or the air in the pump cavity is not exhausted.

The Hazards of Idling

The main impacts on water  pumps  are as follows:

(1) Since there is a large amount of gas in an idling water pump, it is easy to cause cavitation and cause damage to the pump body and flow parts;

(2) Mechanical seals or packing seals are not lubricated by liquid, and dry grinding is extremely easy to cause wear;

(3) If the balance plate of the idling multi-stage split casing pump is not lubricated by anyone, the balance plate will soon be burned and damaged;

(4) There is no liquid in the idling of the water pump, the rotor parts and the pump body are hot, and the temperature cannot be cooled. Thermal expansion and contraction will easily cause some gaps (such as sealing rings) to bite.

Early Warning and Maintenance

(1) Treat each gap position of the split casing pump and expand it under permitted conditions to prevent seizure;

(2) Carry out special process treatment, quenching and tempering, heat treatment, etc. on the shaft of the split casing pump to increase the hardness, and use low-flexibility materials to prevent large swings and seizures during idling;

(3) Use mechanical seals and packing cavities that do not require liquid medium lubrication;

(4) Use closed self-lubricating bearings that do not require oil;

(5) Compared with other split casing pumps, the pump chamber of the self-priming pump has a larger volume and a space where water can be stored. Before the self-priming pump works normally, the cavity should be filled with liquid, and there is a period of self-priming before operation, during which the air is continuously discharged to the pump body, and this period is partly idling;

(6) Set up the idling sensing system. Modern equipment is used to monitor the water pump in real time. When the split casing pump is idling, it will immediately alarm and automatically shut down to protect the safety of the unit.

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