Repairing vacuum pump?
Repairing vacuum pump?
(OP)
We have a damaged SIHI liquid ring vacuum pump, model LPH 60520, cast iron casing and ductile iron impeller. Inner surfaces are pretty worn out, with irregular "craters" throughout side covers and casing, some more than 5 mm deep.
What amazes me is that the pump worked OK, up until the day where we had to install the spare one because some of the "craters" were already leaking into the outside of the casing. This pump is used in a rotary vacuum filter where calcium sulphate is removed from a slurry. Due to misuse/abuse, calcium sulphate sometimes ends up inside the pump, which ultimately caused its demise. :(
My question is, can those pumps be repaired? I´m (probably obviously) totally illiterate regarding vacuum pumps, and our vacuum pump supplier told us (obviously)that it cannot be repaired. We´ll get a new one anyhow, besides the spare, but we have a pretty good machine tool shop that works for us and I´m sure they could coat and grind interior surfaces on the damaged one, if only I knew what tolerances it requires, and if those tolerances are critical or not to the correct operation of the pump. I always thought that since the liquid ring acts as seal between casing and impeller, mechanical tolerances weren´t critical. Any comments? Thanks.
p.s. we do need a good vacuum of at least 20 inHg vacuum in our process.
What amazes me is that the pump worked OK, up until the day where we had to install the spare one because some of the "craters" were already leaking into the outside of the casing. This pump is used in a rotary vacuum filter where calcium sulphate is removed from a slurry. Due to misuse/abuse, calcium sulphate sometimes ends up inside the pump, which ultimately caused its demise. :(
My question is, can those pumps be repaired? I´m (probably obviously) totally illiterate regarding vacuum pumps, and our vacuum pump supplier told us (obviously)that it cannot be repaired. We´ll get a new one anyhow, besides the spare, but we have a pretty good machine tool shop that works for us and I´m sure they could coat and grind interior surfaces on the damaged one, if only I knew what tolerances it requires, and if those tolerances are critical or not to the correct operation of the pump. I always thought that since the liquid ring acts as seal between casing and impeller, mechanical tolerances weren´t critical. Any comments? Thanks.
p.s. we do need a good vacuum of at least 20 inHg vacuum in our process.





RE: Repairing vacuum pump?
What region are you located in?
RE: Repairing vacuum pump?
You could metal or ceramic spray the surfaces and grind back to standard or it maybe possible to overbore the stator and shrink a sleeve into it, tolerance wouldn't be critical provided you have enough end clearance between rotor and stator.
RE: Repairing vacuum pump?
RE: Repairing vacuum pump?
If needed use modeling clay to find the clearance.
Keith Cress
Flamin Systems, Inc.- http://www.flaminsystems.com
RE: Repairing vacuum pump?
They can re[air to real good tolerances to bring back to 'as new' and generate excellent vacuum levels.
They are our agents in the North of England !! www.cdrpumps.co.uk
Ash Fenn
www.cdrpumps.co.uk