Hi Darren,
We split our helium, ref gasses, O2 to 5 peripherals distributed between
two mass specs.
Pros:
Only one regulator, tank, purifier needed
Can help with diagnostics (i.e. running the same tank through different
devices)
Less to tanks to monitor
Less space, tank rent required
Cons:
One leak can impact the whole system
Backup tank, alarm or switch over for helium is advised
A sudden high flow in one area could impact another device
More fittings/leaks are possible
I use 1/4" tubing to all the main split between each mass spec, and 1/8"
tubing to each device. Finally there is a short coil of 1/16" for
moving things. I also put shut off valves at every device so I can
perform maintenance or take it out of service if there is a leak.
We also installed a low pressure helium alarm. In my highest
consumption I go through one helium tank every two weeks. So I use HP
not UHP, and a thermal purifier.
This really has worked fine for us. I have one EA that is mounted a
ways from the 1/4" supply line so when I purge the autosampler I make
sure no peaks are coming out on another device. I can get a short
baseline shift if two EA's are purging autosamplers.
Ben
Benjamin Harlow
Manager, Stable Isotope Core Laboratory
Washington State University
School of Biological Sciences
G-81 Eastlick
Pullman, WA 99164-4236
Office: 509-335-6161
Lab: 509-335-6154
Fax: 509-335-3184
Laboratory for Biotechnology and Bioanalysis (LBB2) Stable Isotope Core
http://www.isotopes.wsu.edu
-----Original Message-----
From: Stable Isotope Geochemistry [mailto:[log in to unmask]] On
Behalf Of Darren R. Grocke
Sent: Friday, May 08, 2009 8:26 AM
To: [log in to unmask]
Subject: [ISOGEOCHEM] Refitting gas lines
Dear Isogeochemist's
I'm refitting some gas lines in the mass spec lab here in Durham and
I'd like some comments and feedback. I'd like to know the Pro's &
Con's of splitting gas tanks - for example, having two helium tanks
feeding through one regulator and helium purger into two separate mass
spectrometers (one with a gas bench and the other with an EA/TCEA
combo)? Also, is it advisable to do this with reference gases too,
such as CO2?
If any of you have experience with this kind of set-up, are there
issues I need to be aware of? Advice on monitoring regulators. Also, a
preference for tubing diameter (1/4 inch, 1/8 or 1/16)?
Any photos showing such a set-up would also be great - please send
directly to ([log in to unmask]).
All and any advice greatly appreciated.
Cheers
Darren
Dr Darren R. Grocke
Reader in Stable Isotope Geochemistry
Department of Earth Sciences,
Durham University,
Science Labs,
South Road,
Durham DH1 3LE
England
[log in to unmask]
http://www.dur.ac.uk/earth.sciences/
Tel: +44 (0) 191 334 2282
Fax: +44 (0) 191 334 2301
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