Re: Vacumm Pups Source

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Luc by way of Terry Fritz <twftesla-at-uswest-dot-net>" <ludev-at-videotron.ca>

Hi Ed 

1. I have a really good one made some years ago by fisher
scientific. It's plastic but really well made better than the one
made for water bed. When I test it some years ago I get near
theoretical vacuum vs water temperature I don't remember the
value gut it's probably simple to calculate or to find a chart on
the net.

2. If you talk about a could trap use in vacuum production (
using a U shape pipe in liquid nitrogen ) no this device is
useful only for high vacuum.

3. The pumping rate.

I know in the beginning of the century people use mercury
aspirator and got vacuum of around .00003 inch of mercury. I
always want to try using a good water centrifuge pomp, vacuum oil
and an aspirator just replacing the water by vacuum oil because
this oil have a low vapor pressure. Who know as high vacuum as
you can reach with set up ?

Luc Benard     

Tesla list wrote:
> 
> Original poster: "Ed Phillips by way of Terry Fritz
<twftesla-at-uswest-dot-net>" <evp-at-pacbell-dot-net>
> 
> Tesla list wrote:
> >
> > Original poster: "Dr. Duncan Cadd by way of Terry Fritz
> <twftesla-at-uswest-dot-net>" <dunckx-at-freeuk-dot-com>
> >
> > Hi Jan, Ed!
> >
> > >Just want to pop in here... with a cheap aspirator you can reach
> > about 50
> > >Torr with a household water faucet, and maybe can do better with
> > higher
> > >water pressure and a better constructed aspirator. <snip>
> >
> > Absolutely right.  I've found the all-glass ones to be significantly
> > better than the plastic ones.  Also if you have direct mains water
> > pressure (kitchen taps are usually direct-to-mains and the one out in
> > my garage is too) it does indeed make a big difference to running the
> > thing off a header tank in the attic.  Finally, the water temperature
> > makes a difference too, because of the vapour pressure variations.  A
> > pump which would pull say 25mmHg in summer would get down to better
> > than 15mmHg in winter, once I measured 8mmHg with a really excellent
> > glass pump, but the water temperature was only around 4C (it was a bit
> > nippy in the lab too ;-)
> >
> > Dunckx
> > Geek#1113 (G-1)
> 
> 1. Where do you get a decent glass aspirator?
> 
> 2. If water temperature makes a difference, as I'm sure it does, would a
> cold trap help in the process?  If so, that would sure be of value in
> the evacuation of capacitors prior to oil backfill.
> 
> 3. Does the inlet water pressure change the ultimate pressure or just
> the pumping rate?
> 
> Ed
> 
> Ed