Inspecting a flood-affected centrifugal creek pump - video transcript

Pat Daley from Daley Water Services describes how to inspect a flood-affected centrifugal creek pump in a case study video.

[Nathan Bradley, property owner]

In this situation Pat, where the water has been over this pump for – possibly at the longest period it was probably under water for at least 12 days – what is the best things to look for? The first thing I would do is obviously clear the debris and then the telescopic slide shaft there and give that a grease ... even though they are greased every day but it has been under water for a long time. The rubber coupling, I mean, whether there is crap in that, whether it needs to be cleared and then obviously all the bearings inside the pump.

[Pat Daley from Daley Water Services]

That's for sure, Nathan, the debris that you can see obviously, but some of the things that you can't see like sediment inside these tyres ... which can not wear everything out immediately but it sends the balance of the shaft ... could be put out of balance quite a bit and that will load up these bearings and also it gets magnified into the back of the engine.

So particularly with high speed engines, this one would not be running at high speed but quite often with high speed engines the tortional vibration that goes into that fly wheel can damage the crank shaft ... so a lot of damage can be done from simply the sediment inside that tyre. They are not an easy thing to pull apart and check but it is well worthwhile in trying to clean it out.

The other areas are that as you stated are that you would grease, well this a good idea to give it probably a little more grease just to see whether any water droplets come out of the bearings ... because if there is any water in there then the temperature when you get the pump going the temperature rises fairly quickly and that's what does the damage to the bearings.

[Nathan Bradley]

Is it a good idea for this time to possibly use high temperature grease instead of general purpose grease?

[Pat Daley]

I would probably go for high temperature grease because it is a little bit higher density as well so it will take up some of those water droplets out of there. The other areas are any of your seals just to make sure the debris is completely clear from the seals, and even the telescopic shaft that you mentioned while it is not a high moving part you will get wear in there if there is sediment sitting in on top of the telescopic shaft.

As far as the pump itself goes any of these pumps that have got a packing gland which that is really the way you are sealing the air out of the pump so that you can prime the pump and keep the prime ... while inside there is gland packing as you would have seen. If you get deposits of sediment in there and you are running it, it will grind away at the main shaft, so it is a good idea to back those nuts off a bit and get an air compressor and blow around the gland packing and just do them back up again as normal. In case you are not sure with gland packing it should have about 5 drips a minute is what you need. You don't want to stop the water coming out because it will burn the shaft and the packing.

The bearings here once again you grease those and look for any signs of water bubbles coming out through the seals cause the seals are not good enough to keep the water in there so the grease pressure will push that water out. If you do see a lot of water in there that's when you would probably look at pulling it apart. But certainly look for the signs of water first. It's the same as for that counter shaft bearing here of course, grease it and observe whether any water bubbles come out.

Moving away from some of this moving stuff though, the other things I do look at the water source that might have changed down there so next time you go to pump you don't want to be putting sand and stuff though the system and you might want to make sure you have a pumping hole there ... and on the discharge here we have an air valve on the non return valve chamber there where you just make sure nothing has built up inside and things like that. But other than that it would be good to go.

Watch the Inspecting a flooded centrifugal creek pump case study video.