Date: Thu, 10 Sep 2020 14:33:05 -0700
Tara,
I would recommend brazing where possible. Most of my system was brazed,
including quite close to the magnets.. I did not notice any significant
outgassing during the pump down to get ready for He introduction and I
would think that any that did occur slowly would be trapped in the He
purification stage. The only place I used compression fittings was
where I attached the He flow gauge, which is plastic. Obviously, heat
here would not work. The fittings did need a little extra tightening
above normal and I checked them with a leak sniffer while tightening to
make sure.
I have attached a couple of pictures of the plumbing around one of my
magnets. You can see where it was brazed versus compressed. As with
your set up, I used 2" copper pipes for the main recovery linesafter
the big shut off valve. As a caution, if you look at the plastic
luovers covering the window, you will notice a bit of twisting in the
ones closest to the pipe. The torch got a bit too close here and
slightly warped them.
Allan Kershaw
Director of Advanced Instrumentation
Department of Chemistry
University of Southern California
840 Downey Way LJS 159
Los Angeles CA 90089
213 740-6376
On 9/9/20 1:47 PM, Tara Sprules, Dr. wrote:
> Hello,
>
> While I am sure there will be discussion of this at the IVAN event
> coming up next week, we may have some plumbing work done prior to
> that, and have had some back and forth about whether the
> polymer/compression fittings the plumber is suggesting (they would be
> ordered for use with helium) would be sufficient to prevent leakage or
> contanimation (offgassing) of recovery lines. The price is supposed to
> be about the same as brazed connections, but the installation of the
> polymer fittings would be much easier- which is a factor to consider
> when working close to 8 magnets. We have established that we will be
> using 2" copper piping, and had indicated that we prefer brazed
> connections.
>
> Has anyone used compression fittings to join sections of copper pipe
> for their recovery systems? Is/was it OK?
>
> Thanks very much,
>
> Tara
>
>
>
> *********************************************
> Dr. Tara Sprules
> QANUC
> Quebec/Eastern Canada High Field NMR Facility
>
> www.nmrlab.mcgill.ca
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(image/jpeg attachment: He_Plumbing_Closeup.JPG)
(image/jpeg attachment: He_Plumbing.JPG)