Wednesday, February 23, 2011

Vacuum System

Gathering stuff for the first panels and other materials while waiting for the shop. I rescued a couple of seized 1/2 hp pumps from the dumpster. These were completely trashed with some kind of vapor that caused extensive rusting of the cast pump stators. The innards were really full of gritty rust, cementing the vanes in the rotor. In each case a pretty beefy 1/2 hp direct drive engine would not turn them!!!  For my use I guess these will do, even if not perfect,  as I don't need a micron level vacuum.  I think the plan would be to debulk with a shopvac and turn these beauties loose on the infusion and bagging.

Welch 8907
These are the inner parts of the pump cassette. I have brushed them to remove as much crust as easily possible. The swept surfaces look better than I had hoped although the vanes are shot. 

Time to get serious with the crust rust.  First step was a hot dip wash with a high energy ultrasonic treatment in anti rust detergent soup followed by a stiff licking with a stiff nylon bristle brush.

Here is the result. Reasonably clean. Unfortunately I broke the casting on the inlet stator while getting the pressed-in shaft face-seal out. Welch are being a bit slow getting back to me re: parts.

Edit: The refurb is going to cost 1/2 a boat buck now, as well as an 8 week wait for the part. Probably still worth it? since I'm still waiting for the township to approve the shop plans

Edwards RV8
This one was really badly siezed, been sitting around for a couple of years untill our recent store room cleanout. There was quite a lot of crusty debris. It was a real problem removing the rotor shaft.  It required the bigger persuader ;-)  Shaft tip a little bent now hope the spyder takes care of that.

This pump is a more sophisticated design than the Welch (it is a 3 stage pump) and if it cleans up I hope I can get the genie back in the bottle on this one.

Edit: Ive been slack about posting, but I have now three 8cft/min pumps. All in good working condition. I think these will be suitable for infusion. Here is how the Edwards pumps cleaned up.

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