As many have done, I purchased the Type700BP (The 710DA for 0-2psi) for use
at the output of my magnets before they tie into the line for our helium
recovery system. The regulators contain a port on the bonnet labeled as a
vent which I believed would vent to atmosphere in the case of over
pressurization upstream. This would protect the magnets in a case when the
helium recovery compressor might shut down blocking downstream flow. Not
the only safety measure, but one I thought existed.
It turns out, after discussion with Control Air, that this vent is
non-functional on the Type 700BP models. They use the same bonnet on a
number of regulators and is a hold over from other designs. In short, this
unit will not vent anywhere other than downstream - and if the downstream
is blocked - pressure will build on your magnets.
I may be the only one who misunderstood how this worked on these back
pressure regulators, but I wanted to send out this warning in case I'm
not. Your helium recovery line will need some other relief valve in the
case in which the recovery compressor were ever to shut off (due to an
interruption in the chilled water supply, for example)
We use a Direct Recovery system for Quantum Design with no intervening
collection bag, so there is no a built in protection as there is in a High
or Medium pressure collection system.
I think the simplest solution is to put a tee off the collection line prior
to connection to the recovery system, and install a 1psi relief valve.
That's my plan at the moment but I would like to hear other suggestion or
thoughts on this.
Best
--
Ken Sharp-Knott
Department of Chemistry
NMR Facility Manager
Virginia Tech
(540)267-6502 (Cell)
(540)231-0885 (Office)
Received on Mon May 10 2021 - 05:24:41 MST