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Technical article
How to deal with the idling of the pump?
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In the operation of centrifugal pumps, pump idling is not allowed, the majority of users are afraid of the idling of centrifugal pumps, the reason is because of the phenomenon of idling do not understand, do not know how to solve well. In fact, centrifugal pump in a short time of idling will not cause damage (within 1 minutes).


The reasons of centrifugal pump idling are: the inlet medium of the pump is insufficient or the inlet pressure is insufficient, or the inlet pipe of the pump is blocked, or the air in the pump cavity is not exhausted.


When the centrifugal pump idles, the impeller has no contact or little contact with the medium, can not effectively work, the liquid can not be conveyed out normally, these are doing useless work. Because there is no effective work, the load on the motor is very small, the generated current is very small, the impact on the motor will be nothing, the pump idle impact on the pump is indeed fatal. The idling pump is easy to cavitate, causing damage to the pump body and flow parts; idling pump mechanical seal form or packing seal form of idling, will not get liquid lubrication, leading to dry grinding, and thus rapid damage; idling pump rotor parts, pump body will be heated, no liquid cooling, expansion and contraction of the role of heat Those narrow clearance positions (such as sealing rings) are easy to lock; the empty multi-stage centrifugal pump balancing disc has no lubrication, the balancing disc will soon be burned to death, damage.


For the early warning and maintenance of centrifugal pump idling, it is suggested to improve the design of centrifugal pumps one level:


First, deal with the clearance positions of centrifugal pumps, expand them under permissible conditions and prevent them from locking.


Secondly, the shaft of centrifugal pump is treated by special technology, tempering, heat treatment, etc. to improve hardness, and low flexibility materials are used to prevent large swing and lock when idling.


Three. Use machine seals and packing cavities which do not need to be lubricated by liquid medium.


Four, choose closed self-lubricating bearings without refueling.


Horizontal self-priming centrifugal pump cavity relative to other centrifugal pump volume space increased, there is a place to store water. Before the self-priming centrifugal pump works normally, the cavity should be filled with liquid. There is a period of self-priming time before operation. During this period of time, air is continuously discharged to the pump body. This period of time belongs to partial idling.


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