gas tight disconnection?

[giume]

Hi everyone.

I work in Nuclear Magnetic Resonance and my samples are glass tubes about 5-10 mm OD.

I need to transfer a solution from tube A to a tube B, with B under vacuum. Then I need to be able to detach tube B from the setup and insert it in the magnet for the experiment.

Any suggestions on a valve/connector that would allow me to detach tube B from the line but keeping the tube under vacuum without leeking air in it?

 

[zeusfaber]

I have a mental image (probably from about forty years ago) of somebody flaming the evacuated tube upstream of the sample until it softens and collapses on itself, then just snapping the sample off in the middle of the collapsed section.

Did I imagine that?

A.

 

[IRstuff]

I think that technique has been around for a while; thermometers and like, etc., so at least 5 centuries.

We've done similar things with vacuum Dewars; we pump down the Dewar through a thin-walled copper tube and crimp/cut in one operation. The resultant vacuum can survive up to 5 years or more.

OP, what material is the tube? What materials can it be?

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert!

https://www.youtube.com/watch?v=BKorP55Aqvg

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[waross]

I called an old friend, retired after a career as director of NMR services at a major university.
With about one inch of sample in an 8 inch NMR sample tube, held vertically use a torch to heat the tube near the top until it collapses and seals.
SOP in NMR labs.

Bill
--------------------
Ohm's law
Not just a good idea;
It's the LAW!

 

[itsmoked]

Perhaps the old standard lab vacuum/gas systems. They use ground glass interfaces with glass ball valves (which are cylinders).

Can't use ANY metal what-so-ever.

Keith Cress
kcress -

http://www.flaminsystems.com