Multistage vs Single Stage
Multistage vs Single Stage
(OP)
Would there be any advantage to use single stage pumps or multistage pumps?
In my application, it would be cheaper to use a single multistage than two single stage in series. It would also take up a whole lot less room to house a single multistage with one backup.
One long time pump salesman told me to avoid using multistage pumps if I could. I think he meant that they are harder to maintain.
Do you see any merit to that arguement? In another similar application I know the other company used some multistage pumps in series and they had no issues whatsoever.
Thanks
In my application, it would be cheaper to use a single multistage than two single stage in series. It would also take up a whole lot less room to house a single multistage with one backup.
One long time pump salesman told me to avoid using multistage pumps if I could. I think he meant that they are harder to maintain.
Do you see any merit to that arguement? In another similar application I know the other company used some multistage pumps in series and they had no issues whatsoever.
Thanks





RE: Multistage vs Single Stage
Now then is a single impellar better or worse than two impellars. I'd go for two impellars normally. The way you can get the required head as per the fan laws is to increase the speed of a single impellar. To get double the head, you'll increase the speed by 1.414. (sqrt 2). But then you'll get 141% of the flow, so you'll need a smaller impellar and so on.
I'd rather have an 1750 RPM pump than a 3600 rpm pump, just call me old fashion, but as they say, speed kills or at least increases the risk. As for the salesman saying multi stage pumps being avoided, his company probabilly didn't make multistage pumps. In the pipeline industry we have no choice and we use as high as 16 stages in a single pump. If you really want to see some multistage, look at a REDA pump, they can have over 50 stages.
RE: Multistage vs Single Stage
The company I spoke with makes multistage pumps as well. These pumps are for a pipeline. He said that the trend for pipeline pumps is more towards having single stage in series rather than multistage pumps.
RE: Multistage vs Single Stage
In the size you are looking at I can't see that a multi stage will be any more of a maintenance problem than a single stage of this size, which ever way to go you are still talking about 5000hp. Although if you can place single stage pumps along the pipe line this is also a consideration but should form part of your study.
Does the company you are speaking with have standard design for your duty or will they need to design something?
RE: Multistage vs Single Stage
The trend is not more single stage in the pipeline industry. The trend is to adjust speed and VFD controls to adjust for different conditions. The trend is to build fewer pump stations and operate at higher pressures. This is a liquid and the pressure drop and HP is nearly linear.
RE: Multistage vs Single Stage
RE: Multistage vs Single Stage
RE: Multistage vs Single Stage
never heard of that. Granted I'm in a totally different field, but nuclear plants use multi-stage pumps and they are required to be highly reliable. I also don't see why a system with multiple single stage pumps would be any simpler than one with a single multiple stage pump. IMO, having multiple pumps equals more chances for something to go wrong..
Patricia Lougheed
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RE: Multistage vs Single Stage
Hopefully someone with some pipeline experience can chime in to give their 2 cents.
Boiler feedwater pumps or clean services which have constant flows and fluid properties would have luck with any pump, I'd say.
RE: Multistage vs Single Stage
"Why don't you knock it off with them negative waves? Why don't you dig how beautiful it is out here? Why don't you say something righteous and hopeful for a change?" Oddball, "Kelly's Heros" 1970
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RE: Multistage vs Single Stage
Your final statement in the original posting seems to say a lot, "__________I know the other company used some multistage pumps in series and they had no issues whatsoever."
RE: Multistage vs Single Stage
If you need redundant pumps, then you could in stall two two stage 5000 HP pumps or three one stage 2500 HP pumps. Now in this application, you'd be ahead.
RE: Multistage vs Single Stage
Good name thou, hope you're over 25...Patricia, as always right, pointed out that a number of things that could go wrong with several pumps instead of several stages of one pump. For fluids with less viscosity, like liquid gases, you need anyway multiple stages to avoid cavitation, to overcome NPSH problems and not lastly, the lubrication of those bearings, using perhaps your process fluid to lubricate and cool the bearings. My 2 cents would be on the multistage when comes to large units and large power sources, one breaks down once, two break down twice.
cheers,
gr2vessels
RE: Multistage vs Single Stage
RE: Multistage vs Single Stage
Slurry pumping over long distances uses multiple single stage pumps, rather than single multi stage pump. Generally slurry pumps do not come in multi stage versions. For variable flow rates as the flow (head) requirements drop off the higher stage pumps are switched off and slurry is pushed through the pump. I would agree with Artsi look carefully at the specific requirements of the process, fluid characteristic range (viscosity/density), flow range and then do the value engineering on it and derive the best answer.
Good Luck, Cheers
Mark Hutton