Relationship between flow rate and pressure in centrifugal pumps
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This post was last edited by foam_ZPTK on 2018-2-25 at 23:16. There is a centrifugal pump at my station, and the outlet pressure is usually around 4.8. But today the pressure suddenly dropped to 4.3. When oil comes to my station from the upstream station, it follows a bypass process; after one hour, the liquid level did not change, which indicates that the pump is still pumping oil, at a rate of about 140 per hour. However, by checking historical data, when the pump pressure reaches 4.8, the displacement is more or less the same. Theoretically, displacement and head are inversely proportional; this is hard to explain. There is another question: can gate valves be installed vertically? Are there any standards for this?
Is the oil the same for both times? You can’t use diesel one time and gasoline another time, right? Is the flow rate measured by a flow meter? On the characteristic curve of a centrifugal pump, the head decreases as the flow rate increases; it does not reverse.
Has the inlet pressure dropped? A decrease in outlet pressure does not mean that the head also decreases; if the head remains unchanged, the flow rate should change little.
To determine the cause of such phenomena, it is necessary to observe how the trend graph of pressure decline looks. If there is a gradual decrease over time, it may be related to damage inside the temperature control equipment; if the change is sudden, then it is advisable to check the instruments for any issues.