Asking for advice on a dry vacuum pump (Wob-l Dry Pump 2585C-02)

[Ilan Pierres]

Hi,

You might have already seen my introduction post, but in case you didn't, I'm trying to build a cabinet around a (demo) fusor (Makezine style).

This involves some constraints, one being the smell and odor released by oil vacuum pumps, which is why I was considering a dry vacuum pump.

I've already looked into vacuum pump recommendations, and it seems that pumps capable of achieving around a 5-micron vacuum are suggested. One example is the Kozyvacu TA500, which is a dry pump. However, when reviewing its technical data, I found that this pump has an ultimate vacuum rating of only 40 microns.

The dry pump I was considering (because it’s a good deal at ~200 euros) has an ultimate vacuum of 60 microns: the Wob-L Dry Pump 2585C-02
https://shop.welchvacuum.com/s/product/ ... et-c8bd6=2

So, I was wondering if a vacuum system with this pump would still work to make the fusor glow at around 5-10kV.

Thanks a lot.

[Dennis P Brown]

Since your only aim is to get a gas discharge, certainly a dry pump (60 microns ultimate) is acceptable and for a permanent display in doors for visitors, a good idea. Through, for a lower voltage system (for safety), best to work in the torr range. In any case, that pump is still excellent for maintaining the vacuum. If the chamber will be evacuated, back filled to operate, then a simple open/close valve would be needed.

I do not know what gas you intend to use for the chamber (deuterium would be a bad idea) so ultimate pressure might or might not be an issue to purge the system before back filling with the desired gas. If argon, I do feel the 60 microns ultimate pressure would be ok. Trace oxygen wouldn't be an issue if you repeatedly exhaust and re-fill three times before achieving the final fill pressure.

Aside: don't know what you will do/require to excite the chamber but certainly a neon sign transformer would be very viable.

Nice project to have and I wish you good luck on finishing it. When you do, PLEASE (!) update us and with pictures!

[Philippe David]

Isn’t noise going to be the biggest issue? I’d optimize for that

[Liam David]

Hold on! That listing says 60 TORR not 60 mtorr = 60 microns. That pump will not work well even for a rudimentary glow discharge, and certainly not a 5-10kV fusor glow.

[Dennis P Brown]

Oh, that is terrible even for a dry pump. I've had dry pumps do well under a torr. Missed that (assumed the poster had the correct info.)

[Ilan Pierres]

Thanks to all of you for your replies, Yes I've looked back at the data and it's way above what's recommended. I'm looking back at normal oil pumps because they seem to have reall good vacuum for quite a low price !

[Ilan Pierres]

I'm know looking at this one : https://valuetool.pl/en/offer/value-pro ... /v-i215s-m
Normal 2 stage oil pump, 15 microns vacuum but only 1,5 CFM, But I guess if the there are almost no leaks for a 1 Litter chamber this would be enough ?

[Dennis P Brown]

This time I looked at the pump. For a demo that just has a bright plasma glow, that will work. Not for real fusion, of course. You'll likely need a few hundred volts to light the plasma but that isn't hard to get.

[Ilan Pierres]

Hi everyone, I finally managed to get all the components together to build my fusor and get my first plasma, it's not great, nor is it uniform but I think by building a better annode next time it will get better.

I also have my (Pretty much) final shape for my furniture piece (Pics attached)
Thanks for your advice to all of you !

[Dennis P Brown]

Well, that design is certainly one spectacular cabinet to say the least! Your a really great artist as well as a fusor engineering technician. I'm impressed and thank you for posting.