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Capillary Gas Fitting

Posted: Mon Jun 03, 2019 11:36 pm
by Mark Rowley
Shown is the capillary gas fitting I plan on using to slowly feed gas into the 2.75” cross chamber. The needle valve will be a slow flow Swagelok SS-SS4. I’m also considering another higher flow valve before that with a T fitting so I can purge the feed line faster.

Mark Rowley

Re: Capillary Gas Fitting

Posted: Tue Jun 04, 2019 6:27 am
by Richard Hull
Carl Willis and one or two others have, in the past, used that exact tiny bore SS tubing, but about 10 feet of it carefully coiled up in a 4 inch diameter to really deeply reduce the flow rate. Carl later settled on a precision laser drilled disc to warrant a precision flow rate over a variable gas line pressure range.

I have actually bought several of these coils with attached swagelock fittings as part of vacuum assemblies used in the medical and fab systems at hamfests and even at our yearly HEAS gathering.

Carl's original posting is well buried in past posts. The locating of this old post is an exercise left to the student.

Richard Hull

Re: Capillary Gas Fitting

Posted: Wed Jun 05, 2019 5:12 am
by Mark Rowley
Richard,
I think this may be the thread you were referring to. I vaguely recall reading it 13 years ago.

viewtopic.php?f=6&t=2631&p=15853&hilit= ... oil#p15853

Mark Rowley

Re: Capillary Gas Fitting

Posted: Wed Jun 05, 2019 5:46 am
by Richard Hull
You found it! Wow! I am suitably impressed. Yes, that was when I was still in the 500K top end with Fusor IV. Carl was a leader in gas flow control ideas. Actually, he was always a super innovator as was Jon Rosenstiel. Ultimately, Jon would blow past us all in Neutron numbers and, along with Carl, did some of the first activation work and submitted gamma spec charts by the dozen.

Richard Hull