In the operation of centrifugal pumps, the idling of pumps is not allowed. The vast majority of users are afraid of the idling of centrifugal pumps. The reason is that they do not understand the causes of idling and do not know how to solve them well. In fact, centrifugal pump idling in a very short time will not cause damage (within 1 minute).
The reasons for the idling of the centrifugal pump 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 is idling, the impeller has no or little contact with the medium, so it can't work effectively, and the liquid can't be transported out normally, which are all idle work. Because there is no effective work, the load on the motor is very small, and the current generated is very small, so the impact on the motor will not be much, and the impact of pump idling on the pump is indeed fatal. The idling water pump is easy to cavitate, causing damage to the pump body and flow passage parts; the idling of the mechanical seal or packing seal of the idling water pump will not get liquid lubrication, resulting in dry grinding, thus causing rapid damage; the idling water pump rotor parts and pumps will experience heat, without liquid cooling, and those narrow gap positions (such as sealing rings) are very tolerant due to the effect of heat expansion and cold contraction Easy to bite; idle multi-stage centrifugal pump balance plate without whose lubrication, balance plate will soon be burned, damaged.
It is suggested to improve the design of centrifugal pump to a higher level in the early warning and maintenance of centrifugal pump idling:
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 bearings without oil filling.
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 pump body, which belongs to partial idling.
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.
