[labnetwork] Automated Emergency shutoff valve

[John Shott]

Matthieu:

While I have no specific experience with this particular emergency gas 
shutoff valve, I've got a bit of experience with some things that send 
remote shutoff signals to cylinders.  Before I share my experiences with 
you, I want to make sure that I understand how your are hoping or 
planning to use this valve.  To be honest, if all of the details have 
been handled properly, this seems to be a pretty clever approach.

On what gases are you planning on using this valve?  They are clearly 
advertising it for use with chlorine but it is not clear that it will 
work with other CGA and tank valve configurations (including cylinders 
equipped with DISS fittings).  While automated shutoff would also be 
attractive with many of our toxic friends, I'd be very leery of using 
this with silane, germane, DCS, hydrogen, ammonia, or methane  ... or 
anything this is flammable ... for fear that the motor (which could be 
in close proximity to a leak) is not designed/rated for such use and 
could ignite a fire before it got your cylinder closed.

Second, is this likely to be used in gas cabinets?  And do those 
cabinets already have a pneumatically controlled valve that shuts off 
the gas somewhere in the pigtail before it gets to the regulator?  If 
so, have you worked out the details of how this automatic valve would 
work in concert with the pigtail valve both in emergency shutdown 
situations and in normal bottle change events?

I do like being able to shut cylinders remotely ... in addition to gas 
detection shutdowns, seismic shutdowns, and signals from fire alarms, 
smoke detectors, etc., we have a total of 14 "break glass" emergency 
shutdown switches scattered throughout our lab that are located in any 
area where a gas leak could happen.  These just become digital inputs 
into our TGMS PLC.  That gives us a convenient way of shutting down all 
gases quickly and remotely .... even if a gas detector hasn't "smelled" 
anything.

While most of our gas cabinets still use only pneumatically controlled 
shutoff valves in the pigtail we are gradually migrating to use of 
pneumatic cylinder valves.  We currently use pneumatic valves on all of 
our 100% germane and silane cylinders.  I like being able to shut those 
gases at the cylinder rather than pretty close to the cylinder ... 
particularly since a lot of leaks occur at the CGA/DISS connection.  Our 
gas cabinets have front panel selection of whether we are using 
pneumatic cylinder valves or hand wheels ... so that is convenient for 
us.  I'm not sure that pneumatic cylinder valves are common on all gases 
and in all locales, so that may not be an option for all.  Where 
pneumatic cylinder valves aren't available or a viable option, I think 
that this motor drive is a clever approach and worth exploring ... 
particularly if it can be use on just about any CGA connection and 
cylinder valve.  I'd feel even better about it if it were rated Class 1 
Div 2 so that it could be used on more flammable/pyrophoric gases ...

I'll be curious to hear if our gas handling friends at Critical Systems 
and some of the other folks with much gas handling experience have to 
say ... but I think that anything that allows you to close a cylinder 
without having your nose 15 cm from the CGA connection is worth some 
careful exploration.

Let me know if you have any further questions and good luck with your 
renovation.

John


On 5/14/2015 10:02 AM, Matthieu Nannini, Dr. wrote:
> Collegues,
>
> Our facilites dept. is reviewing our operations before a 
> « used-to-be-not-so-major » renovation. They are flirting with this 
> idea of installing Emergency Gas Cylinder Valve shutoff like sold by 
> the following company: http://www.halogenvalve.com/
> These valves would be hooked up to our TGMS.
>
> Any of you has such an installation ? Anyone could comment ?
>
> Thanks
>
> -----------------------------------
> Matthieu Nannini
> McGill Nanotools Microfab
> Manager
> t: 514 398 3310
> c: 514 758 3311
> f: 514 398 8434
> http://mnm.physics.mcgill.ca/
> ------------------------------------
>
>
>
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