Why isn’t there a pressure gauge on the balance pipe of a multi-stage pump?
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As the title suggests, our company’s horizontal multi-stage pumps of model 11 do not have pressure gauges on their balance pipes. If the gap increases due to wear of the balance disc, the pressure difference on both sides of the balance disc decreases, resulting in an increase in the axial force; in severe cases, this can lead to damage to the bearings. How can one determine whether the balance disc is worn out without a pressure gauge?
Because during the factory testing of multi-stage pumps, the axial force is already balanced by using balance pipes, orifice plates, adjusting the size of pipe joint holes, or modifying valves. The balance disk has the ability to adjust itself automatically; so what’s the need for a pressure gauge? Even if the end face of the balance disk wears out, the gap between it does not increase, as the balance disk will automatically move the entire rotor, restoring the gap to its original state and thus achieving dynamic automatic balancing. It is not the situation where the gap increases and leads to a loss of balance, as one might think.
Then why was there a pressure gauge on the balance pipe of the high-pressure sealed water pump at my previous employer, Calit Ebara, and why did the reading on the gauge increase gradually as the balance disc wore out?
Could it be that the wear amount has exceeded the limit of self-adjustment?
It is possible to install a pressure gauge, as a reference for the settings at the time of manufacture and also for those who are not familiar with the device. However, the pressure indicated by the gauge should not increase due to wear and tear; such a situation would indicate that the automatic balancing function of the balance disc has failed. Make sure it is a balance disc structure rather than a balance drum structure
So it’s not a disk that is being ground, but a drum
It combines a disk and a drum; the gap between the disks is fixed, not dynamic
As long as there is a balance weight, it is dynamic balancing!