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Junior Member
 
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Last Login: 2/1/2008 6:26:27 AM
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| | We are looking at putting some Gorman Rupp (or pioneer) type pumps for a sewage pump station, because is eliminates the cost of a new pumpwell. What is peoples experience in this situation? Do they rag up any worse than the screw type impellers of flygt submersibles? How often do you have to derag? Presently we have been offerred the pioneer P4 and P6. We have been advised the suction lift is 7.5 m at our speeds (1450 rpm). Is this achievable in practice. I will do a NPSH calculation. Regards Grant H, Australia |
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Supreme Being
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Last Login: Yesterday @ 6:27:09 AM
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| | Grant, I would do the NPSH calc and allow a good margin. A wide margin will be necessary to ensure that the pump will pass solids and rags under difficult circumstances. Regards TerryF |
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Last Login: 3/25/2008 7:07:46 PM
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| | Terry, My experience is that priming at or near 7.5 meters is not overly reliable. NPSHR aside, there is a practicle matter. The pump curve may say it can do it, but flooded suction pumps (ie..submersibles) will provide greater reliability. If you have a ragging problem, have you ever considered a chopper pump for the application? Might be worth a look.
Marc |
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Supreme Being
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| | I agree , hence my comment to allow a wide margin. Regards TerryF |
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Junior Member
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Last Login: 2/1/2008 6:26:27 AM
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| | Your reply regards suction lift and NPSH is noted. Also if the sewerage includes some warm industrial waste, the temperature elevation would significantly affect the NPSHa. I am not keen on mascerator pumps, because the cutters need regular maintenance in gritty environments. Has anyone had hands on experience with Gorman Rupp pumps pumping raw sewage? Also, can they compare the performance against submersible sewage pumps? Thanks Grant |
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Supreme Being
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Last Login: Yesterday @ 6:27:09 AM
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| | Grant, I have seen photos of them on sewage pump stations as the primary pumping plant but have no personal experience. Some of the pumps used by hire companies for emergency pumping are GR. I have looked at using them in a treatment plant to replace a submersible waste activated sludge pump but i only had a maximum suction lift of 3 metres but i stayed with a flygt because i couldn't get the flows i required. Personally i would be wary of specifying one of these where it was routinely required to operate at high suction lifts in sewerage conditions. In saying that they are an interesting concept and as an industry we should always be open to new and different ideas. Regards TerryF |
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Supreme Being
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Last Login: 6/18/2008 10:17:32 AM
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| | I've had about 10 years experience with both. We currently have 6 G&R pumps 4 of which are pumping raw sewage. They are pretty reliable and I would much prefer a dry well set up than submersible pumps. We don't have much trouble with these pumps clogging. Usually when we do have clog it is in the discharge check valve not the pump. It depends on the nature of the waste to be pumped. Domestic? "A prison system? Still domestic kind of." |
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Supreme Being
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Last Login: 6/26/2008 4:01:08 PM
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| | I know what you mean by the "kind of" qualifier. Main differences that I've seen with prisons are : relatively high strength wastes ( BOD >300) because of low flush toilets, food wastes from kitchens, and lack of I / I, and very large spikes in flow, due to regimentation of activities. Also, lots of screenable type stuff ( e.g., plastic packets that condiments come in). Another thing that is apparently pretty common is for the prisoners to stuff sheets and such into the toilets, in order to cause flooding. This is done to force a move to a different cell, and for the general principle of aggravating the guards. That could really add to the clogging problems you describe. |
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Last Login: 3/27/2008 4:23:09 PM
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| J.W.Koch (11/27/2007)
I've had about 10 years experience with both. We currently have 6 G&R pumps 4 of which are pumping raw sewage. They are pretty reliable and I would much prefer a dry well set up than submersible pumps. We don't have much trouble with these pumps clogging. Usually when we do have clog it is in the discharge check valve not the pump. It depends on the nature of the waste to be pumped. Domestic? "A prison system? Still domestic kind of." The City I work for has over 100 GR pumping raw sewage in it's system. I agree that they are good running pumps. The only time we really have to pull one open is when something that shouldn't have been in the system to begin with gets caught in the impeller. Another thing i like about them is that they are easy to work on. You have to be careful with the oil seals though when you rebuild one. |
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