Envirosafe

[Stephen Santoliquido]

Another method sometimes used in situations where the desired evacuation
rating can't be reached or can't be verified or if it can't be held for some
reason (other than because of a leak), if you have dry nitrogen available,
is to evacuate, charge dry N2, evacuate, charge dry N2 then evacuate once
more.

On Tue, Oct 28, 2008 at 12:56 PM, George Selby <gselby4x4 at earthlink.net>wrote:

> At 12:25 PM 10/28/2008, you wrote:
> >A home style compressor is pretty useless for this.  I have a similar
> >venturi unit, and it only pulls a decent vacuum on a BIG industrial
> >compressor.  Also good to keep in mind that the compressor will be
> >running constantly for the half hour of so it takes to establish a decent
> >vacuum.
>
> I have the same type unit, and it works OK for me on a 4HP
> compressor.  It is really useful to see if you have any leaks (pull
> it as low as it will go, then close the valves and see if it holds
> vacuum.    By pulling the vacuum in about 3 stages, allowing the
> compressor to recover in between stages, I can get the vacuum down to
> within a pound of the specs, which has always worked for me.  The
> biggest problem I have is moisture starts accumulating inside the
> venturi device where the air from the compressor comes out, and this
> starts interfering with the pulling of the vacuum.  So I would
> recommend having a moisture trap on the line from the
> compressor.   One final note - it is very loud.  If you have nearby
> neighbors, the combination of the air compressor running contantly
> and air coming out at full speed is quite obnoxious.
>
> George Selby
>
>
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