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Re: Cheap vacuum pump


From: 	Alfred A. Skrocki[SMTP:alfred.skrocki-at-cybernetworking-dot-com]
Sent: 	Sunday, November 02, 1997 3:33 AM
To: 	Tesla List
Subject: 	Re: Cheap vacuum pump

On Friday, October 31, 1997 11:48 AM Mike Harrison
[SMTP:wwl-at-netcomuk.co.uk] wrote;

> >Years ago I read an article in an ancient volume of "Scientific
> >American" magazine.  The author described how to build a vacuum pump
> >using a rotary compressor from a discarded refridgerator.  He vented
> >the freon, drained out the old oil, & refilled it with vacuum pump
> >oil.  Of course, he had to solder on a few pieces of copper tube for
> >hookup.  He used it to make a homebrew x-ray tube, so it must've
> >pulled a pretty hard vacuum!  For poor coilers who can't afford a real
> >pump, this sounds like a cheap & interesting experiment that could
> >lead to better poly caps.  When I get back to the US I plan to try it 
> >myself

The refrigerator compressor used in the old conversions is the infamous 
Rolator compressor and when properly converted worked BETTER than the 
$500.00 + Welsh vacuum pumps! Don't giveup hope finding them though, I
found one lying at the curb just last year, so they are still to be found.

> I wonder if it would be possible to convert one of the very cheap  car
> tyre inflator pumps into a vacuum pump - I've not had one apart, but
> if it can generate 30-60psi to inflate a tyre, it outta suck fairly
> well! Or maybe it would just suck :-)

All the tire inflation pumps I have ever taken apart were either diaphram 
pumps or sloppy piston pumps, neither of which make even reasonable vacuum 
pumps! Insteayou should be looking at the automobile air-conditioner 
compressor for some of them are rotory blade compressors just like the old
Rolators and the Welsh vacuum pumps. I remember a few years back that 
the BELL JAR (Steve Hanson's vacuum head newsletter) There was some 
discussion about identifying which automobile air-conditioner compressors 
would convert well for vacuum pump usage, as to what progress has been made 
on that endevor, I have no idea. Steve has a WEB SITE at;

    http://www.tiac-dot-net/users/shansen/belljar/


                               Sincerely

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                           Alfred A. Skrocki
                   Alfred.Skrocki-at-CyberNetworking-dot-com
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