Two suctions
Two suctions
(OP)
I have a small 30 gpm centrifugal 3 hp 3500 rpm pump with two suctions. One suction is small and close to pump, the other if large but far more distant. Both are same elevation. When starting up the flow favors the nearer chamber and quickly empties it first. I attribute this to the much lower inertia of the water in the small chamber. My solution was to nearly close the valve to the nearer smaller chamber. I will probably change that to a small orifice. My question is this: How do I predict such a difference in startup flow between the two chambers? And how do I size the restrictive orifice to the smaller chamber? Note that the two chambers are piped together just before the pump suction. The smaller chamber contains the pump start stop switch based on level. No need to tell me it was a messy design. It was hemmed in by location requirements.





RE: Two suctions
RE: Two suctions
To attempt to get equal flow, which is what I assume you want, you need to get the overall frictional losses, assuming there is no head difference, a equal as you can. This will be difficult with any fixed device like an orifice so some sort of variable control is advised if you really want to get true equal flow.
My motto: Learn something new every day
Also: There's usually a good reason why everyone does it that way
RE: Two suctions
By the way, mwinn , I doubt if "a pump with two suctions " is a proper term for what you mean.
RE: Two suctions
My motto: Learn something new every day
Also: There's usually a good reason why everyone does it that way
RE: Two suctions
It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)
RE: Two suctions