Why Does Centrifugal Pump Run Idle? What's The Harm?

Why does centrifugal pump run idle? What's the harm?

 

The idling of centrifugal pump is harmful to the pump, which may cause cavitation or damage to mechanical seal. Today we will explore the reason and harm of the idling of centrifugal pump.

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1. Reasons for idling

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

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2. Harm of idling

The impact on water pump mainly includes the following aspects:

(1) Because there is a lot of gas in the idle pump, it is easy to cause cavitation phenomenon, which will damage the pump body and the flow passage parts;

(2) There is no liquid lubrication in mechanical seal or packing seal, so dry grinding is very easy to cause wear;

(3) no lubrication of the balance plate of the multistage centrifugal pump is carried out (official account: Pump housekeeper), and the balance tray will be burned and damaged quickly. 

(4) There is no liquid in the idle running of the water pump. The rotor parts and the pump experience heating and fail to get cooling. The thermal expansion and cold contraction are easy to cause part of the clearance (such as the sealing ring) to bite.

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 3. Early warning and maintenance

(1) The clearance position of the centrifugal pump shall be treated to expand under the allowable conditions to prevent it from seizing;

(2) The shaft of centrifugal pump is treated by special process, such as tempering, heat treatment, etc. to improve the hardness, and low flexible materials are used to prevent large swing and seizure during idling;

(3) Use the mechanical seal and packing cavity which do not need to be lubricated by liquid medium;

(4) Select sealed self-lubricating bearing without oil filling;

(5) Compared with other centrifugal pumps, the volume space of horizontal self-priming centrifugal pump increases, and there is a place where water can be stored. Before the self-priming centrifugal pump works normally, the cavity shall be filled with liquid, and there is a period of self-priming time before operation, during which air is continuously discharged to the outside of the pump, which belongs to partial idling;

(6) Set up idle induction system. Through the modern equipment for real-time monitoring of the pump, when the centrifugal pump idling immediately alarm and automatic shutdown, to protect the safety of the unit.