The self-priming capacity of centrifugal pumps
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A storage tank and its feed pump base are at the same elevation (0 meters). However, the pump inlet pipe extends from the top of the storage tank down to the bottom of the tank (a height of about 3 meters), and then passes through a section of horizontal pipe before dropping down to the pump inlet. In other words, this inlet pipe actually creates an upward pouch at the pump’s inlet (the piping cannot be adjusted). When a bottom valve is installed on the pipeline inside the storage tank, does this pump still need to be considered based on a 3-meter self-priming height? It can be treated as a regular centrifugal pump.
Surely suction is being taken into consideration, and it’s not just the suction capability of 3m – pipe pressure drop and other factors are also relevant.
I think it’s possible, as long as the pump outlet valve is closed tightly before stopping the pump and there are no leaks, and the liquid level in the storage tank is above the outlet of the insertion tube; in that case the liquid won’t flow back, so it’s not necessary to fill the pump
A regular centrifugal pump will do; the inlet pipeline must be filled with water before starting, as there should be no air present. .
Depending on the usage, if the requirements are not high, a simpler diaphragm pump will suffice; there’s no need for filling the pump or anything similar
I have not encountered this design in practice; when selecting a pump, the 3m self-priming height need not be considered, but the impact of resistance in the inlet pipeline must be taken into account. Additionally, under normal conditions, the temperature of the tank must be taken into account to prevent cavitation at the top of the 3m-high inverted U-shaped tube; otherwise, it will cause problems. My humble opinion