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Check Valve and Cavitation

PostPosted: Wed Jan 02, 2013 4:19 pm
by lwparchive
I work for a water company in Montana. We have various wells and booster pumps. I have a question concerning one of your pumps.
I am just wondering where is the best place to install a check valve, (2") on one of your pumps which we use as a booster pump. The suction side is about 30 PSI while the high side is about 138 PSI. Currently we have two of these booster pumps which seperately pump approx. 95 GPM each, but together it goes to approx. 180 GPM, although this changes with the level of the Reservoir. The reason i am asking is that in many of our booster stations they only get rebuilt say some where after around 10 to 20 years of service.
But at this particular site it happens to be at a more frequent rate. The cycle seems to be about every 2 1/2 to 3 years. So i was wondering if the check valve could have anything to do with the impellers getting washed out.
The impellers were bascially washed down to nothing (20% - 30%). The check valves are currently on the suction side (which is 2") and are probably located approx. 8" from the pump casing. The discharge side is 1 1/2". It appears to be from cavatation, although there is an air relief valve placed accordingly for this possibility. And it is in working order, and does not seem to pass much air if any. The suction side of these pumps are directly fed from a 6" line, which is approx 2' above the pumps themselves. Any correspondence would be greatly appreciated!!!

Re: Check Valve and Cavitation

PostPosted: Tue Mar 26, 2013 2:33 pm
by dlamp67
There could be an issue with the check valve being on the suction side of the pump. This could cause a situation where the pump is not getting enough inlet water to pump causing possible cavitation. I would relocate the check valve to the discharge side of the pump.