What could be the problem causing the pressure of the DG horizontal multi-stage pump to fluctuate, as well as the high temperature at the outlet?
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This post was last edited by lee2033 on 2016-12-14 at 19:08. A 75KW DG horizontal multi-stage pump experiences fluctuating discharge pressure during operation, as well as varying current levels (ranging from 40–50A to 200A). When the discharge pressure is low, the temperature at the outlet is high; it’s quite hot to the touch. I don’t know what the reason is? The valves on the inlet and outlet pipelines have passed a preliminary check and are fully open. The bearing housing temperature is not high either. What could be the problem?
I searched online and found that \"emptying\" refers to the situation where, during normal operation of the pump, it suddenly starts making noise, vibrating, experiencing a decrease in head and flow rate, reduced efficiency, fluctuations in motor current, and pressure gauge readings that fluctuate or even drop to zero. If any of these symptoms occur, it indicates that the pump has become empty. ” “There is also this phenomenon: if the pump’s flow rate is high, the liquid being pumped cannot reach the required flow rate, resulting in vacuum formation. ” If there’s time available, how should it be handled? There are 5 pumps in use at the site; the others all work normally, but this one exhibits this issue whenever it is operated alone.
Based on the situation you described, it is recommended that you check for cavitation in the impeller (of the equipment)； Observe whether the pump’s vibration increases when the outlet pressure is low; it is also possible that the inlet flow rate decreases momentarily (due to operational factors).
Cavitation: Is the inlet filter clogged?
Close the outlet valve, check the current level, and then open the outlet valve to 25%, 50%, and 100% respectively to observe the fluctuations in current. If there are no fluctuations at 25%, the fluctuations are minor at 50%, and significant fluctuations occur at 100%. Try it this way. It seems that there is a problem with the process pipeline, or perhaps the control valve on the outlet pipeline is not sensitive enough.
It is likely that either the inlet is blocked or the inlet piping is not properly configured; other pumps are taking away the flow rate from this pump.
Check the inlet pipeline to see if there is any flow
Check the section before the pump of the faulty pump