How do I configure a helium recovery system that won't perturb my magnet's stability?
I'm concerned that just hooking up a hose that connects the helium exhaust of all our magnets to a community recovery system shared with EPR and Physics labs is going to lead to pressure fluctuations that will compromise our magnets' stability, specifically its lineshape stability.
I know we should have one-way valves in place, but well before I arrived our engineer removed the Bruker one-way valve from the magnet and instead placed a more industrial-looking one-way valve at the manifold on the wall.
My main question is whether we need to purchase a manostat to enhance stability. They cost ~$10K, which isn't a trivial chunk of our maintenance budget.
I'm open to any suggestions.
asked Dec 15 '09 at 05:10
Here is what I found on the AMMRL archive (ammrl login and password applies). These are summaries from different years: 1997, 2001 and 2007. The posts also have some information on who has such systems.
Pressure maintenance does seem to be a concern.
The recovery system can place either an increased pressure or a partial vacuum downstream of the magnet check valve (one-way), depending whether the collector is full or being pumped out. This variable pressure downstream of the check valve will certainly vary the pressure inside the magnet, because the check valve operates according to the differential pressure between inlet and outlet. The magnet mfr. assumes the outlet is at atmospheric pressure. To avoid pressure fluctuation in the magnet, a helium manostat would indeed be necessary. The question I would ask is whether the pressure fluctuations without a manostat are great enough to cause significant problems in the spectra, and for that I have no definite answer.
answered Jul 23 at 10:45