Re: vacuum pump
A simple glass trap, inmersed in a container with an "eutectic" salt and
ice mix will lower the vapor pressure of water to almost -17 °C, this should be
lower than the oil's water vapor pressure.
Tesla List wrote:
> Original Poster: Ed Phillips <evp-at-pacbell-dot-net>
> 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