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hi all,
i need to calculate the power of the pump, supplier sent me a diagram so that i can calculate the output power of the pump and he told me that the equatuion is
power = pressure x Dicharge but @ the selected air input pressure to the pump
We use:
Inlet flow rate of liquid is 60 lit/min= 16 g/min @ 8 bar
therefore the pressure of outlet liquid will be 82 psi
power= 82 x 16 / 1714 = 0.76 hp
which is illogical.
could anyone lend me hand in solving that problem,
thank u in advance,
marwa

first question is why do you need to know the "power" of the diaphragm pump? if to see if you have enough compressor, the pump supplier should be able to give you a curve of flow and output pressure vs cfm at various air pressures at the pump air inlet. if you need to know if the pump will produce a req'd flow and output pressure, use the same curve. hopefully you have an idea of required system pressure, which will give you a minimum air pressure you will require (some diaphragm pumps can actually produce output pressure of twice the inlet air pressure). normally though you must exceed the system pressure req'd in air pressure supplied, otherwise the pump is basically balanced and won't pump. the nice thing about a diaphragm pump is they are inherently variable speed by adjusting the input air pressure - assuming you have enough compressor capacity. you mention 8 bar - is this your plant air system pressure (118psi)? knowing this and some idea of system pressure req'd at your design flow rate will give you an idea from the pump curve whether this pump will work or not, assuming you are within stnd diaphragm parameters on other fluid characteristics.