Pump backflow issue
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I heard from an old colleague that, for centrifugal pumps, under normal operation, smaller pumps usually have backflow while larger pumps do not. Regarding this, no relevant specifications or reasons have been found. I would appreciate the help and guidance from fellow sailors. Thank you!
This needs to be determined based on the operating conditions. In general, whether it is a small pump or a large pump, it should not be under pressure for an extended period of time.
So do you think it is reasonable for the small pump not to experience backflow while the large pump does experience backflow during normal operation? What is the basis? Thank you!
There is some truth to this; typically, the minimum return line for small pumps uses a throttle orifice plate, which ensures that there is always flow； The minimum return line for large pumps usually uses a flow control valve; when the pump is operating normally, this valve is closed, so there is no flow.
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It is related to the minimum continuous operating stable flow rate of the pump and the minimum flow rate required for thermal control
Thank you all for your generous help; I personally agree with the suggestion from the 4th floor. Thank you!
Perhaps the small pump has low power, and continuous backflow can prevent pressure buildup without consuming much extra energy. Large pumps have high power, and continuous backflow indicates an unreasonable design; such backflow requires a lot of electricity
Generally, centrifugal pumps have an appropriate range for pressure and flow rate; the smaller the pump, the narrower this range. Small pumps are usually specified with a capacity that is higher than necessary. In the absence of backflow, the pump pressure remains high at low flow rates, and since small pumps have poor pressure resistance, well, you can imagine what happens.