Ross Mackay Forum Moderator 94 Posts
Re: Why is there a difference in pump output?4 January 2010 at 1:29pm
In approaching this problem, it must be remembered that the centrifugal pump is a slave to the system, so when there is a difference in pump output, there must be a difference in the system to require that change.
With a discharge pressure reduction from Pump B to Pump A, (and assuming these pumps are identical!) there must be a difference in the total head required by Pump A. Such differences can only come from the system. As you indicate there is a difference in the suction side of the two pumps, then it would be logical to assume that the difference is the source of the problem.
Hope that helps.
Must the suction lines of parallel pumps be equidistant? In our plants (petrochemical), we normally have two pumps installed in parallel, one running and the other stand-by. Every 20 days we change the pumps (stop the one that is running and start the one that is in stand-by). During change of pumps, we do not have a problem, except with two pumps, which pump cyclohexane (cold) and there is not a equidistant arrangement between the suction lines of the pumps. But the problem is only with one of the pumps. For example, we have two pumps -- A and B. When A is running and we change to pump B, we do not have problem, but when are going to do the contrary, (Change B to A) we note a discharge pressure reduction.
Have an insight or suggestion?
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