Hello all,
A couple of months back I asked about brazed vs compression fittings for connecting copper pipe for a helium recovery system.
We have just finished testing our copper pipe header, which comprises around 400 ft of 2" copper pipe that will carry the boiloff from 8 instruments in two connected buildings to our helium recovery system. After an initial test with compressed air, when one faulty join was found, we flushed the system thoroughly by repeatedly pressurizing to ~25-30 psi of helium and releasing it. (As I realized when I did the math, this takes only a portion of a standard helium gas cylinder!).
Finally we filled to 25 psi with helium at the end of the day last Friday. When we got to checking it on Wednesday the pressure had held! The plumbers used the Veiga ProPress system with EPDM seals.
It remains to be seen how it performs under operation. We don't anticipate issues with temperature, as there will be ~20 ft of 1/2 inch flex steel lines connecting the magnet exhaust to the recovery line at each instrument. In terms of holding helium gas, it seems to work! As I know there are a number of people at various stages of planning and installation I wanted to pass on our experience to date, and will certainly update once the system is up and running (should be early 2021).
Best wishes,
Tara
On 2020-09-09 4:47 p.m., 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
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Dr. Tara Sprules
QANUC
Quebec/Eastern Canada High Field NMR Facility
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Received on Thu Nov 26 2020 - 14:57:57 MST