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Jim Wilkins[_2_]

wrote in message
...
On Saturday, May 27, 2017 at 2:26:40 PM UTC-4, Steve W. wrote:
wrote:
If a centrifugal pump with a maximum pressure of, say, 10 psi is
supplied with water at 80 psi will the water pressure coming out
of
the pump be 90 psi? I think the pressure will be 90 psi. Am I
wrong?
Thanks,
Eric

IF the volume of water remains constant the pressure coming out
will be
at most 80 psi. if the pump is designed to produce 10 psi. It may
be
lower depending on the size of the housing and the restriction the
impeller creates. Say your input side is 2" and the pump can
produce 10
psi. at zero head pressure out of a 1.5" outlet.

Feed that pump with an 80 psi head pressure and the pump won't add
any
pressure because it cannot pump faster than the water is already
flowing
through it.

That's exactly what I thought, but Jim's reference to multi-stage
pumps threw me. Since water isn't compressible, I don't see how the
multi-stage pumps work. For gas, no problem, but I don't get it for
liquids.

--
Ed Huntress

That reference showed it could be done, but not how. I was hoping it
would lead someone who knows more than I do about fluid dynamics to a
better description.