Suction Spools

Yes. Do you have a specific pump in mind?

yes...

Can we now begin the slow, confusing process where you reluctantly describe your pumping system and we finally understand the whole situation ?

Let us begin..

Is the suction piping diameter the same size ( or smaller than) the pump suction nozzle ?

Do you have an MBA ?

So cynical after such a short time?

I do like the MBA reference.

Sizing up the suction one size at the pump flange is such a standard feature that I would suspect anything smaller. I'm a retired Steamfitter, but we all suffered through integration by parts. Buy the swedge and the larger pipe; cavitation is worth avoiding.

I'm not sure what you mean by "suction spool" It this simply a section of piping leading to the pump inlet? Or some other part of the pump, like what is commonly referred to as an inducer? Or some specialized stationary hardware in the suction piping?

Also drbobwoolery, what is a swedge?

Ed Weldon

Swedge is another term for a reducer. The first piece of piping off the suction side of a pump is a short spool which can be dropped out to service the pump with minimal disruption of surrounding piping.

Short answer to OP is "yes". The reason for a suction spool or spool piece is actually twofold. The intake of a pump creates great turbulance in the medium and the installation of a spool actually smooths out the flow, which in turn improves the performance of that pump. Secondly a spool piece can be removed in order to access the volute and impellar, without stripping complete pump, of standard centrifugal pumps. The length of this spool should be five times the diameter in length to ensure the smoothing. ( if your suction pipe is 100mm in diameter the length of the spool must be 500mm.)

Another way of achieving the smooth flow is to install one size larger on the intale line. Elbows or bends should never be installed directly to the inlet (suction) of a pump. irrespective of pipe sizing.