Velocity Limit at Centrifugal Suction Flange
Velocity Limit at Centrifugal Suction Flange
(OP)
I have seen pump suction velocity limit recommendations of between 5 - 7 ft/s. Assume this is for the suction pipe, however what are the velocity limits at the pump flange? Goulds model 3196 centrifugal pump appears to have very high velocities at the pump inlets. For example the 1.5x3-10 has a 3 inch suction while the pump curve extends beyond 360 gpm. This corresponds to velocities upwards of 17 ft/s at the pump inlet which appears improper. Is there a published guideline for velocity at pump inlets?





RE: Velocity Limit at Centrifugal Suction Flange
The velocity at the pump inlet is the pump manufacturer's responsibility.
RE: Velocity Limit at Centrifugal Suction Flange
Inlet piping is often, though not always a larger diameter than the discharge line / header due to issue over friction losses and NPSH, but you need to size for your conditions.
My motto: Learn something new every day
Also: There's usually a good reason why everyone does it that way
RE: Velocity Limit at Centrifugal Suction Flange
RE: Velocity Limit at Centrifugal Suction Flange
RE: Velocity Limit at Centrifugal Suction Flange
RE: Velocity Limit at Centrifugal Suction Flange
My motto: Learn something new every day
Also: There's usually a good reason why everyone does it that way
RE: Velocity Limit at Centrifugal Suction Flange
RE: Velocity Limit at Centrifugal Suction Flange
Maybe what your supervisor is referring to is the practice of selecting pumps to operate at higher speeds than lower speeds. Higher speeds result in a less expensive pump but with a shorter lifespan. Pumps that operate at lower speeds tend to last longer.
RE: Velocity Limit at Centrifugal Suction Flange
The inlet velocity in the suction nozzle to a pump is not really comparable to the velocity in pipe, it's an integral part of the hydraulic design. The inlet nozzle size is related to the eye area of the impeller which is related to the flow rate the pump is designed for.
Answer me this: if you think a 3" suction is too small for 360 gpm, what do you think about the 1.5" discharge on that pump? Doesn't the 360 gpm have to exit the pump as well?