Why isn’t the pump delivering enough flow?
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Our workshop is equipped with 2 multi-stage horizontal centrifugal pumps, model 3Y-50×6. The two pumps share a common filter, and the medium transported is residue oil. When Pump A is started, it operates normally; however, when Pump B is started and the outlet is slightly opened, the pressure drops from 3 MPa back to 0 MPa, in less than half a minute. What is the reason?
Is there any leakage at the inlet, or is the valve at the inlet damaged?
*Check with AN to see if the pump is connected in reverse
Has the outlet pressure of both pumps dropped to 0, or is it pump B?
Coking of the residue pump or blockage in the impeller flow channels due to coking
It’s better to draw a schematic diagram of the specific process for easier analysis. Is what the poster is trying to say this: when the pumps are started separately, Pump A operates normally, but when it’s Pump B’s turn, the problem described occurs? Is it still Pump A that is running, and does the pressure drop once Pump B starts and the outlet valve is opened? Also, could you clarify whether 3 MPa is a normal pressure after B is started? The conditions for describing the sensation are not sufficient.
It should be disassembled for inspection; preliminarily, it is estimated that there might be a blockage in the flow channel, or problems with the internal components, gaskets, etc. Please carry out a disassembly inspection, and we hope the original poster will share the results of that inspection so that we can learn from them.
Is the impeller corroded? Is there any leakage in the casing?