Sciencemadness Discussion Board

Ultra high vacuum

XeonTheMGPony - 20-8-2016 at 05:08

Most ultra high vacuum systems require a turbo molecular pump or a vapor diffusion pump.

Now I have worked with the latter, and they can be messy as now days they use oil instead of Mercury and they require heating and such, and the other fun point is vapor can some times go on a trip and slowly coats the chamber if your baffling isn't well set up.

I was wondering, based off ion engines why not use an electrical field to accelerate remaining gas molecules to the rotary vane pump?

https://en.wikipedia.org/wiki/Electrostatic_fluid_accelerato... < Concept

No oil or moving parts, silent operation (Moot point I guess giving the rotary vane pump will be making noise)

So my question is: Am I missing any thing glaringly obvious that would render this idea non functional?

For those curious my old now stolen system used a 56L stainless steel keg as the chamber and a small refrigeration system as the water trap the evaporator was built inside a pressure cooker packed with Stainless steel wool scrubbers then to the diffusion pump then rotary vane pump (2stage)

Gauges where ion gauges and thermister digital.

Basically I plan to just carbon copy my old design but if possible get rid of the diffusion pump and try my linear direct current accelerator pump idea.

Possible fabrication styles and means of functioning:

http://www.thomastownsendbrown.com/hydro/images/pump5.jpg

http://www.ee.washington.edu/research/seal/projects/EFAproje...



[Edited on 20-8-2016 by XeonTheMGPony]

[Edited on 20-8-2016 by XeonTheMGPony]

[Edited on 20-8-2016 by XeonTheMGPony]

unionised - 20-8-2016 at 06:11

Like this?
https://en.wikipedia.org/wiki/Ion_pump_(physics)

XeonTheMGPony - 20-8-2016 at 06:40

Quote: Originally posted by unionised  
Like this?
https://en.wikipedia.org/wiki/Ion_pump_(physics)


Similar but rather then capturing, compressing, basically replacing the use of the turbo or vapor diffusion pumps.

But I'll give that a more thorough read.

But it is seeming more and more the idea is worth while to make a prototype for!

careysub - 20-8-2016 at 06:50

There is this:


Attachment: basu2015.pdf (1.6MB)
This file has been downloaded 567 times


yobbo II - 13-9-2016 at 12:58

What is your opinion of this vacuum gauge.
Thanks

http://www.ebay.co.uk/itm/Old-ROBINAIR-Thermistor-Vacuum-Gau...

XeonTheMGPony - 17-9-2016 at 05:37

Quote: Originally posted by yobbo II  
What is your opinion of this vacuum gauge.
Thanks

http://www.ebay.co.uk/itm/Old-ROBINAIR-Thermistor-Vacuum-Gau...


Pretty old but looks like a good one Robin air tends to be good quality, can't go wrong for the price.

The heads are a consumable though, so it may need to be replaced, but if it is reading eradic clean with pure isopropyle alcohol first as oil will sod up the readings if it gets on the thermister.

unionised - 17-9-2016 at 08:13

It won't measure down to anything like UHV.
You may not be able to obtain spare measuring heads for it.
It will probably need calibrating.