Modifying a Edwards nEXT400IID Vacuum Pump for Fusor Use

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Aaron_Brimmer
Posts: 3
Joined: Sun Jan 19, 2025 12:11 am
Real name: Aaron Brimmer

Modifying a Edwards nEXT400IID Vacuum Pump for Fusor Use

Post by Aaron_Brimmer »

Hello all!

I recently came across a nearly free nEXT400IID (B832-00-816) turbomolecular pump that I was able to pick up. The problem that I am having now is determining how to adapt this specific pump to a standard ISO/DN flange. This pump appears to be purpose built for Thermo Fisher mass spectrometers (see the link below for what I mean) so has a specifically designed upper flange for (conceivably) mounting into their machines. The flange is meant to "allow evacuation from three vacuum chambers" but the specific plumbing of these ports appears that anything other than the primary turbo inlet won't receive high vacuum. I've looked around for service manuals for potential machines that may have schematics of how it attaches but to no avail. Before I go through the arduous process of designing an adapter for this pump, has anyone modified one of these pumps before or know someone who has? I'm already designing an adapter but if someone else has already done the work...
https://www.ajvs.com/product_info.php?p ... ry_id=1840

Image

Please let me know if you have any insight into this or advice on how to design the adapter! I'll happily post my progress/design files here if it comes to that.

Best,
Aaron
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Taylor Romain
Posts: 41
Joined: Mon Oct 03, 2022 5:20 pm
Real name: Taylor Romain

Re: Modifying a Edwards nEXT400IID Vacuum Pump for Fusor Use

Post by Taylor Romain »

It seems like configuring this pump for fusor use may involve significant effort, given the need for modifications and adapters. It might be more practical to sell it and opt for a standard turbo molecular pump that’s easier to integrate. Alternatively, you could use a simpler solution, such as the Kozyvacu TA500 2-stage vacuum pump, which can achieve single-micron pressures and might better suit your needs with less hassle.

See: viewtopic.php?t=15463

Also, you should introduce yourself in the Introduction section so the members can gauge your goals and where you’re at in acquiring a chamber, high voltage power supply, and compliance to safety.

Taylor
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Rich Feldman
Posts: 1562
Joined: Mon Dec 21, 2009 6:59 pm
Real name: Rich Feldman
Location: Santa Clara County, CA, USA

Re: Modifying a Edwards nEXT400IID Vacuum Pump for Fusor Use

Post by Rich Feldman »

Welcome, Aaron.
As Taylor says, it would be good to introduce yourself and give an outline of your project.
You talked about ISO flanges, but nothing about fusors outside of one word in the Subject line.
Maybe you want to explore high vacuum after, or in parallel with, fusors.
You have earned some respect by posting in New User Chat Area; many noobs have put more primitive questions in Vacuum Technology area.

I think if you have a working turbopump in hand, including controller,
and you are handy with designing and fabricating adapter-like things, why not go for it!
Shame to waste a beautiful rotating machine.
Show pictures of your pump inlets surface and what you plan to put on it.
All models are wrong; some models are useful. -- George Box
Aaron_Brimmer
Posts: 3
Joined: Sun Jan 19, 2025 12:11 am
Real name: Aaron Brimmer

Re: Modifying a Edwards nEXT400IID Vacuum Pump for Fusor Use

Post by Aaron_Brimmer »

Thanks for the reply Rich and Taylor!

I went ahead and introduced myself on the new user section so I hope that supplies some clarity :)

Some even more background:

I already have a functional DS102 rotary vane pump that consistently gets me to ~8 micron but these regions are still well above my required vacuum of likely less than 0.1 micron (since electron beams can't be generated above approximately that level). As far as I'm aware, some rotary vane pumps can reach this level but will have such a small pump rate that any amount of contamination will ruin the vacuum. Since I'm very comfortable both in CAD and doing metalwork, I figured it would be reasonable to try and get a turbo that I could modify to fit my situation.

To that point, I've actually already designed the adapter and ordered material...

It's designed to use standard ISO flange clamps to attach to the pump then clamps on the top to attach to a standard ISO mount. Should be readily machinable on a manual machine (what I plan on doing). I only modeled the upper flange of the turbo pump so that's what you see on the model. Here's what the assembly looks like, but I'll wait to post any files/drawings until I've actually ensured that this adapter will work...
Attachments
Isometric View Top.png
Isometric View Bottom.png
Cross Section View.png
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