Why can’t centrifugal pumps be run in reverse for a long time
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This post was last edited by foam_ZPTK on 2018-5-16 at 20:42. I would like to ask why centrifugal pumps cannot be run in reverse for long periods of time, and why the cooling water for these pumps must be stopped when its temperature drops below 80 degrees
I don’t understand what you mean Reverse? Pump in reverse? Stop below 80 degrees? Park?
Why can’t centrifugal pumps be run in reverse for a long time? Why does a centrifugal pump have to wait until the temperature drops to 80 degrees before stopping the circulating water?
If it is reversed for a long time, the impeller of the centrifugal pump will fall off.
Reversing can easily cause the impeller to loosen or fall off, and it may also lead to further damage to other components.
In the case of large centrifugal pumps equipped with sliding bearings, reversing the pump will cause the bearings to be destroyed immediately. The cooling return water temperature should generally be kept below 60°C, as higher temperatures accelerate scaling. As for the need to shut down the machine when the cooling water temperature reaches 81°C, this is likely a design consideration – it is set at that temperature because the bearings, oil seals, mechanical seals, or other sealing elements of the pump exceed their maximum tolerable temperature at that point. Normally, the machine should not operate when the cooling water temperature reaches 80°C……
If the pump rotates in reverse, on the one hand, it may cause the impeller to come loose; on the other hand, it can also lead to the separation of the dynamic and static sealing surfaces of mechanical seals that require a specific rotation direction. If foreign objects get inside, it will result in leakage from the mechanical seal.
When a centrifugal pump is reversed at low speed for a short period of time, it generally does not cause any harm, but it is not allowed to be reversed at high speed for an extended period. 1. The various components of the pump are designed for normal operation of the pump within its efficient range; if it operates at high speed in reverse, it may cause certain components to be subjected to excessive stress, disrupting the force balance and affecting the sealing gaps ； 2. In some pumps, the impeller and other components are secured using nuts depending on the direction of rotation of the pump; if the pump operates in reverse at high speed for an extended period, these securing nuts may loosen or even fall off, leading to accidents.
If the pump runs in reverse for an extended period, the impeller will come off, the internal components will be damaged, and it will not be able to deliver any flow