Re: vacuum pump

Tesla List wrote:
> Original Poster: "Antonio Carlos M. de Queiroz" <acmq-at-compuland-dot-com.br>
> Tesla List wrote:
> > I need to vacuum it out.
> > I was wondering if a vacuum pump intended for auto repair would work for
> > this purpose.
> If you like to build things, I once made a vacuum pump that could
> not be simpler. I cut a plastic pen in two, so I had two tubes, one
> ending in a point with a small hole. The internal space of that pen
> was just enough for the paint charge. One end of the other half I
> shaped as a funnel. I then mounted the two tubes with the point
> close to the funnel inside a section of a larger tube (1"),
> with both ends closed by plastic disks. At one end, I fixed an
> additional pen tube to be used as output connection through another
> hole in a disk. All the joints were firmly glued, air tight.
>              +---------+
>              |         |
> water in ====|===> >===|===== water out
>              |        ==== vacuum
>              +---------+
> With water from a reasonably high pressure source flowing
> (a few meters drop), the vacuum goes easily to the boiling point of
> water, about 0.5 cm Hg.
> Antonio Carlos M. de Queiroz


        Have often wondered if a water aspirator of this type would be OK for
the kind of evacuation being discussed here, but worried over the vapor
pressure of the water vapor in the "vacuum" line.  Freeze trap would
take care of that, I guess.  Wonder if you have any thoughts on the