Breathing Air Pump Filter?

I have a new old stock Gast 1023 3/4 Hp vacuum/blower pump and would like to
use it to supply a hood for painting, blasting, etc. with remote air. I know
this pump is used for some breathing air applications but I am unsure of
exactly how they filter out any impurities introduced by the pump, or if it
is necessary. Does anybody know what's needed on the outlet side of the
pump? Thanks.
Reply to
ATP
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Are you positive that it's never been used? For my remote air, I simply use a stack of ten fans, with paper crosses in between each one, all inside a cardboard sleeve. Works well, and produces quite adequate flow even at the end of long lengths of 1" tube. And no possibility of nasties in the air. Low power and quiet too.
Reply to
Ian Stirling
What are the "paper crosses" for?
Reply to
Ken Moffett
If you put two fans next to each other, then the total pressure created by them is nearly the same as one fan. This is due to the air coming out of the fan rotating in the same direction as the fan, so the next set of fanblades just stalls.
If however you place card dividers in the airflow, in the form of crosses, so that the air from each fan blows through them, then it is stopped from rotating, and each fan adds to the total pressure.
Reply to
Ian Stirling
Yes, I opened the box. I bought several of them at an auction, all in the original shipping box from the manufacturer.
Interesting.
Reply to
ATP
I guess this is also seen in various forms of machinery like turbofan engines and pumps, where there are stacks of interleaved rotating and stationary fan blades. The air from each stage is re-directed in the opposite rotation direction I suppose.
Jim
Reply to
jim rozen
What is the general design of the pump? Is it just a shop-vac type thing? If so, there is little problem. Oil sealed pumps or oil lubricated pumps of any sort are troublesome, as you've got to ensure no oil gets into the breathing gas. Any pump that involves oil lubrication and high pressure can in principle generate CO. This can also happen if the oil mist/vapour is in the inlet airstream.
Reply to
Ian Stirling
I'm jumping in cause I've used the Gast pumps in machines. I think they are dry carbon vane pumps. They are noisy as hell and I don't have a clue as to whether they are "man-rated" to supply breathing air.
Reply to
Jim Stewart
Gast also makes diaphragm-type pumps. Those would be a better choice than a carbon vane pump. The second would be almost the worst choice.
Jim
Reply to
jim rozen
Yes. There are probably better shapes to use than the cross, but it's easy to make.
Reply to
Ian Stirling
GAST does make rototy vane pumps for breathing purposes. We used them for "medical air" in retrofitting a Beech King Air to an air ambulence (many years ago). Of course we had filters and traps on the input and output. Check page 4 of:
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Reply to
Ken Moffett

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