Sanitary couplings with Viton seals for High Vacuum?

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Jaron_Veld
Posts: 4
Joined: Mon Dec 19, 2022 2:23 pm
Real name: Jaron Veld

Sanitary couplings with Viton seals for High Vacuum?

Post by Jaron_Veld »

Hi guy's,

I wanna start building a high vacuum setup but i'm starting from blank (Bought two Turbo pumps yesterday, still working on my motor controller)
I've stumbled across these Tri-Clamp couplings on aliexpress and they look a lot like KF type couplings used in high vacuum.
The Tri-Clamp types are normally used for 'Sanitary' applications, so bewing, food production etc.
Could this system be used in combination with Viton seals for high vacuum?
I've already bought some samples and gonna build an adapter for it soon.

Just curious on your opinions on using them for High vacuum.

Also, what material is easily machinable and works good for high vacuum applications?
I'm now casting and machining aluminium and brass but they both seem not ideal for high vacuum. Any idea's?
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Emma Black
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Joined: Wed May 11, 2022 9:42 am
Real name: Emma Black

Re: Sanitary couplings with Viton seals for High Vacuum?

Post by Emma Black »

Hi Jaron,
After buying a very cheap tri-clamp sight glass to use as a gas dryer a while ago I was surprised how close they are to KF fittings, expect the clamps seem a bit more heavy duty. You may need a centring ring for the seals so they have pressure on them it all directions, unless you get something to fit in the clamp groove exactly, but I can't see any reason why they shouldn't work for a reasonable vacuum level. Would be interested to see the results, as these fittings are very inexpensive.

Some on here have fusors with shells completely machined out of aluminium, so it will be just fine for most fusor levels of vacuum.
Jerry Biehler
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Location: Beaverton, OR

Re: Sanitary couplings with Viton seals for High Vacuum?

Post by Jerry Biehler »

Tri-clover fittings should be fine with most levels of vacuum. They are just non-standard and won't mate up properly with existing vacuum components. They are usually made from 304 stainless which is food grade vs 316 which has better corrosion resistance.

Nothing wrong with aluminum or brass for vacuum. A lot of older vacuum hardware is made from brass and you can silver braze it. Not so much any more. The issue with brass is brazing, you need to use hard solders that dont contain cadmium to prevent outgassing. On roughing lines you can get away with generic solder though. I have use cast aluminum plate for base plates and have had no issues, I use the cast aluminum tooling plate like MIC6.
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