Aluminum CF Flanges

[Brian McDermott]

Does anybody know a supplier of aluminum CF flanges? My research project (pyroelectric crystal fusion) requires flanges with better thermal conductivity than stainless steel. Lesker has them, but the 4.5" flanges we need are $185 each and the special gaskets are $120 for 10. Is there another supplier or is this as good as it gets?

[Raymond Jimenez]

Hi Brian,

Atlas Technologies (http://www.atlasuhv.com) sells some aluminum CF flanges, although they have an SS insert for the actual knife-edge, so you can use the normal Cu gaskets. They also cost an arm and a leg, though. Lesker's probably as good as it gets.

Raymond J

[Brian McDermott]

Yeah, we were looking at those too, but $608 a pop is too much to justify the improvement in thermal conductivity.

[Andrew Seltzman]

You could use a SS flange with a copper insert for cooling.

Andrew Seltzman
www.rtftechnologies.org

[murrayim]

Brian,

Check out solid copper gaskets.

http://www.duniway.com/images/pdf/pg/p- ... lat-fl.pdf

If you use a solid gasket on a bored conflat flange, you can conduct heat directly through the copper gasket.

Ian Murray

[Doug Coulter]

I bought some ISO style 6" aluminum flanges for about $100 each, I needed the AL for other reasons than conductivity, but these use Viton O rings so they can't be heated too much. Most people needing to get heat in or out of a vacuum use feedthroughs that allow fluid to be piped through (and you can use them for electric feedthroughs at the same time). I like some of the ideas above, too.
Though SS isn't very conductive at all, though a thin section it's pretty good. One of my electrical feedthroughs is made of very thick copper for high current, and it also does OK moving the heat around.

You might want to consider a redesign along more conventional lines than pulling heat through a flange that way. Obviously you could make your own fluid feedthrough by drilling a couple of copper pipe sized holes in a standard blank flange, then silver soldering them in. For small stuff there's little trouble with thermal expansion problems.
Curl up the tube inside, and (silver) solder copper flashing to it to have a plate heat collector.
If you need electrical insulation too, I know no way other than buying one.

http://www.ancorp.com

Might help you. With Lesker, if they didn't make it themselves and its not obvious where else to get it, it tends to be marked up rather severely. You're paying for their service in aggregation and tech support, which is sometimes a good deal.

[bevan]

I work for Leskers Europe and saw your request. Aluminum flanges are a bit of a pain - not many people want them. Their primary use is in low magnetic applications (synchrotron rings) where they compete against 316LN SS flanges - which are so espensive that it is almost worth making an aluminium chamber, even though it is a pain to weld to the same standard.

The essential problem is economy of scale - we sell 1000's of SS conflat flanges so we can make them cheap. Alu flanges are sold in the 10's or maybe 100's, so, although we keep stock, they are expensive because of machine setting and them not really worth the bother, especially as they need aluminum gaskets to work - copper is unreliable with aluminium knife edges.

I used to work for ITL, manufacturing in europe for many of the big US companies and we would always no bid aluminium CF flanges - not worth the bother.

What base pressure are you going for? If it is not too high (1x10-8, possibly 9's) , I would suggest that you use a KF50 (NW50/QF50) aluminium flange with an alumium metal seal - it can go lower than viton and the QF50-200-AB are cheap as chips - list price is $10.00, the clamps are $14.00 and you could mate it with a SS KF50 port. Only problem is getting a metal seal - we can get them for you in Europe and I am sure that Leskers US could. If not, getting a ring in aluminium that is basically diamond shaped should not be too difficult - If you want I could get you dimensions that would work. If your base pressure is within 1x10-6, you may even get away with a viton centering ring, it would even form an electrical contact for you.