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I know this might not be the most ideal place to ask this question, but I couldn't think of any place better.

I recently purchased a high vacuum chamber setup and have been disassembling it for transport. I removed the hot cathode ion gauge, and then on further inspection, I realized it used an unfamiliar mounting flange. It is a gendered connection. Does anyone know what type it is?

male flange with brass? gasket

same side

I was weary of trying to remove what looks like a brass gasket. It's pretty thin.

female end - no CF style knife edge

same side as above

No Conflat style knife edges, but the edge on the first step is fairly sharp, and might ramp upwards (hard to tell)

dimensions

mes
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  • I understand there was only the brass gasket? Can you add dimensions, diameters etc? – mart May 04 '20 at 19:34
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    @mart There was nothing else, unless I dropped it (pretty sure I didn't). That doesn't mean there wasn't supposed to be something else there. After all, when I removed the turbopump that had a CF flange, someone double stacked copper gaskets, so who knows what else they did/didn't do.. Using a tape measure, on the female side I got 2" OD, then 1 3/8, then 1 1/4 for the ID of the small ledge and finally 1", and didn't bother with the welded bit. The male end had essentially identical dimensions. It's fairly tight, but I wouldn't call it an interference fit. – mes May 04 '20 at 20:00

1 Answers1

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I have some experience with high vacuum so thought I put in my two cents along with what I was able to find on this particular flange. My first inclination was this is a custom unit and I have since checked with my vacuum community and they are of the same opinion.

Here is an exact quote from the most serior person in our group, "Looks custom. I would think an o-ring would fit over the shoulder in that thin groove and then get compressed when the two flanges are bolted together".

I have come across several unique flanges, especially when it comes to cathode gauges mounting to the chamber side. Here are a couple I just pulled off the shelf in the lab:

enter image description here

These will likely never see service again and are kept for the extremely unlikely event that they might be useful to someone down the road who could have them machined for their particular application.

Here are some photos of some connections that are currently installed on my 80's era General Ionex Tandem Accelerator:

enter image description here

The main point I am making is even though conflats and KFs are ubiquitous today, odd configurations were common a few decades ago and it is usually to deal with attaching the cathode gauge(s) to a custom vacuum chamber. In my experience these unusual pieces work quite well so long as the are in good condition, cleaned and installed properly with good and correctly sized o-rings.

If you need help locating a new o-ring - brass, copper, gold or otherwise, PM me; although it looks like yours is probably fine (assuming there wasn't also a rubber unit, but that is unlikely)

Good luck with your new system, and hope this helps!

eatscrayons
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  • Thanks, eatscrayons (user name is familiar. Can't remember from where). Your answer makes sense, especially in light of the fact that much of the equipment in the setup originated in the 80's. I personally never ended up using the equipment as I found a flaw in my theory which precluded the need for experimentation. I have since donated all of it to the local maker space. – mes Dec 21 '22 at 03:03
  • No problem mes, and a good final destination for used lab equipment. Good luck with the growing hypotheses, science is an amazing place to work! – eatscrayons Dec 22 '22 at 21:18