2 Diffusion pumps + extras

Every fusor and fusion system seems to need a vacuum. This area is for detailed discussion of vacuum systems, materials, gauging, etc. related to fusor or fusion research.
Post Reply
Nicker
Posts: 29
Joined: Tue Jul 21, 2009 12:14 pm
Real name: Nick DePasquale
Contact:

2 Diffusion pumps + extras

Post by Nicker »

I recently got two pumps from eBay.
I have no experience with diffusion pumps. Can anyone give me a basic idea on these two that I got, and any idea what all the extra hardware is attached to the NRC one?

As to cleaning them, taking them apart looks fairly easy, a suggestion on what I can use to clean the insides? (steelwool, cloth).

Thanks

-Nick DePasquale

















Tyler Christensen
Site Admin
Posts: 551
Joined: Mon Feb 23, 2009 9:08 pm
Real name:

Re: 2 Diffusion pumps + extras

Post by Tyler Christensen »

It looks like the NRC one has a lot of valves on it. The inlet has a pneumatic bonnet valve connecting to a roughing pump and also directly connects to the outlet via another pneumatic valve going into a cross. There are also a number of vacuum gauges, however it looks like the one on the inlet is damaged. There also looks to be some sort of a trap on the outlet going to where the chamber would go.

It is essentially setup like this: http://privatewww.essex.ac.uk/~bolat/ba ... ystem.html

You can get some idea of how to operate the valves on that page. It is a nice setup to have all those valves since it allows for you to take your chamber to atmospheric while leaving diffusion on, even though that isn't too necesary for fusion work.
Chris Roberts
Posts: 60
Joined: Sun Jul 06, 2008 8:35 pm
Real name: Chris Roberts

Re: 2 Diffusion pumps + extras

Post by Chris Roberts »

I do have an EP-2A diff pump which I am going to use on my fusor. One helpful thing I can offer is the amount of oil it requires. It took me a couple of calls to various people to find out, but from what the consensus was, it takes 100ml of oil. I have not been able to run mine and find out for sure, but that is at least a start.

As far as cleaning it goes, you can just reach into the inlet and carefully pull the pump's diffusion stack, or "christmas tree" out, and undo the 6 screws holding the top and bottom halves together. Then, you may give it a thorough cleaning, I used rubbing alcohol. I would not particularly recommend acetone, as it degrades the o-rings. Then, you can just reassemble it and assuming the heater works you are good as new. Hopefully some of this helps.

-Chris
Nicker
Posts: 29
Joined: Tue Jul 21, 2009 12:14 pm
Real name: Nick DePasquale
Contact:

Re: 2 Diffusion pumps + extras

Post by Nicker »

Thanks Tyler for the explanation on the giant NRC monster I have. Like you stated, it is a nice setup, but not needed for what we are trying to achieve here. So i'll take it apart it all apart, see what guages I have and clean the pump.

Chris cleaning seems easy enough, thanks.
User avatar
Doug Coulter
Posts: 1312
Joined: Sun May 27, 2007 3:18 pm
Real name: Doug Coulter
Location: Floyd, VA, USA
Contact:

Re: 2 Diffusion pumps + extras

Post by Doug Coulter »

To me, this looks like a "lets bounce this off that, and measure the other thing" piece of stuff. Very nice score!

Down the road, you'll find having all these nice fittings around will help with fusor experiments, which chamber I assume is the last picture here. Looks like the diff pumps are air cooled? They need some sort of cooling, so be sure to have that, or all the oil will wind up elsewhere.

We use the pretty-cheap diffoil from lesker while we learn about diff pumps. (my other cars are Pfeiffer turbos ;~). There's better oil around, probably not the silicone type stuff for fusors, but stuff that doesn't put an insulation layer on your electrodes (santovac), but it's costly and not for while you're still learning not to have it go into the chamber or backing pump.

Looks like you've got some interesting sensor heads on this -- look them up. They may be pretty valuable/useful.
Why guess when you can know? Measure!
Post Reply

Return to “Vacuum Technology (& FAQs)”