Does anyone have experience with rebuilding a pump? We're considering that as an alternative to new
Does anyone have experience with rebuilding a pump? We're considering that as an alternative to new
(OP)
I haven't yet gotten cost quotes, but what does everyone think about rebuilding a pump instead of purchasing a new one? Can we expect like new performance and reliability out of it? We'd be going to a professional pump rebuilder.
I don't know what the condition of our current pumps is, just that they output 100-200 psig below their pump curve pressures.
I don't know what the condition of our current pumps is, just that they output 100-200 psig below their pump curve pressures.





RE: Does anyone have experience with rebuilding a pump? We're considering that as an alternative to new
RE: Does anyone have experience with rebuilding a pump? We're considering that as an alternative to new
If you have a swimming pool pump that costs $400, replace it every time. If you have Cat-Cracker bottoms pump that costs $500K, rebuild it every time. I fit falls somewhere in between, then apply the above formula.
Generally a loss in pressure is due to your running clearances opening up due to wear; that is, the wear rings between the pump case and impeller. This causes a portion of the high pressure fluid exiting the impeller discharge to slip back into the suction side of the pump through those clearances. This results in wasted power, increased erosion, and some other crap that you don't want happening. These open clearances could be caused themselves by other things, such as bearings wearing out, imbalance, running the pump at a bad place on the curve.
If you would provide more detail on the pump you have, the service it is in, etc. some of the pros on this site can assist you with some very detailed info on your next step with regard to repair/replce options. Please don't expect detailed and informative answers to general and blurry questions. Sorry if this is offensive to you; but I am a grouchy old man.
RE: Does anyone have experience with rebuilding a pump? We're considering that as an alternative to new
RE: Does anyone have experience with rebuilding a pump? We're considering that as an alternative to new
Dub mac is right though - a vague question = a vague answer. Your call.
My motto: Learn something new every day
Also: There's usually a good reason why everyone does it that way
RE: Does anyone have experience with rebuilding a pump? We're considering that as an alternative to new
RE: Does anyone have experience with rebuilding a pump? We're considering that as an alternative to new
Our pumps are RotoJet RGB III 2x2. Rated at 60 gpm and 2370 head-ft. I don't yet know the original cost or rebuild cost. Pump curve linked here: http://imgur.com/vWsyztA
@1gibson: We want a VFD system, because yes, they are oversized for the majority of use. The pumps in question are used in our high pressure water system. The draw on the pumps is mostly low (~20 gpm) when a few hoses are used, but we want it capable of high capacity (~120 gpm) for when the full cleaning crew is on site. The 200 psi low is not such a problem when just a few hoses are used, but is a major problem when more people/hoses use the system.
@LittleInch: Yes, I know this is significant, and I'm trying to figure out the best energy solution for us. Mostly we are low flow, but the pump has to be capable of putting out high flow, and we want high pressure regardless of flow.
RE: Does anyone have experience with rebuilding a pump? We're considering that as an alternative to new
If you want "high pressure regardless of flow" then you do not want VFD's on centrifugal pumps. VFD will lower pressure by the ^2 of RPM change, and head by the direct ratio of RPM change. This usually means that 1 big pump can't provide the required pressure at very low speed (as you have mentioned above.)
RE: Does anyone have experience with rebuilding a pump? We're considering that as an alternative to new
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: Does anyone have experience with rebuilding a pump? We're considering that as an alternative to new
So my thoughts are for you to work out for how long you need different flows, get a new efficient pump for your flow which occurs the majority of the time then add additional pumps to get your max flow which occurs "occasionally". Don't forget vfds have significant additional losses when looking at power costs.
My motto: Learn something new every day
Also: There's usually a good reason why everyone does it that way
RE: Does anyone have experience with rebuilding a pump? We're considering that as an alternative to new
You should evaluate your service. This pump is not going to perform well in a service with abrasive solids. It acts like a centrifuge, concentrating the solids in the rotor until they build up to the level to grind off the end of the pitot tube. You could try a pitot tube made of a harder material or coated to resist the erosion. But, ultimately, this pump type is not well suited to services with heavy solids present.
Johnny Pellin