[labnetwork] Gas delivery cylinders and lines

[Dennis Schweiger]

Bruce,

everything Tom has stated is right on the money in regarding longevity of a
corrosive gas delivery system.  Here at the University of Michigan our
Chlorine, Boron Trichloride, and Ammonia, systems have been in use since
about 2002, and look just as good as the day we installed them.  We use all
automated cabinets, DISS cylinder connections (CGA is crazy for any HPM
material like this), and shoot for a bottle change cadence of about every
12-18 months (short filling the cylinders so that the product life isn't
compromised).

You're welcome to stop by and have a look if you're ever up this way.
Dennis Schweiger
Lurie Nanofabrication Facility
University of Michigan

734.647.2055 Ofc


On Fri, Feb 22, 2013 at 6:28 PM, Tom Britton <
tbritton at criticalsystemsinc.com> wrote:

>  Hello Bruce,****
>
> ** **
>
> The life of a corrosive gas system is a function of how clean you keep the
> gas. Moisture is the enemy of most corrosive gases, and it doesn't take
> much to wipe out your system. We've been reconditioning gas cabinets for 12
> years now and have been around these systems for close to 30 years and
> we've seen systems that last a couple of weeks and others that are still
> running strong after 10 years. The difference between the two is how the
> systems are cared for.****
>
> ** **
>
> Here are a few things you can do to maximize the life of your gas systems:
> ****
>
> ** **
>
> 1. Make sure to adequately cycle purge your gas cabinet when changing
> bottles. Always use the automated cycle purge function on your gas cabinet
> and set it to a minimum of 75 cycle purges. What this does is effectively
> remove the corrosive gas before you open the connection and allow
> atmosphere to enter the tubing, and then removes the atmosphere effectively
> after you install the bottle, before you reintroduce the corrosive gas.
> Your higher quality gas cabinets will pull a vacuum on the pigtail to the
> primary shutoff valve, before you open the gas cylinder, so you don't mix
> spec gas with N2.****
>
> ** **
>
> 2. Make sure that you have the "trickle purge" option for the process
> purge enabled, and that you quickly change cylinders. The trickle purge
> allows a small amount of nitrogen to fill the tube during the cylinder
> change so atmosphere can't migrate up the pigtail, while the quick cylinder
> change minimizes the time that the tubing is open to atmosphere.****
>
> ** **
>
> 3. Always use DISS fittings for both the spec gas AND purge gas. No CGA
> fittings! With DISS fittings you get a high purity connection as opposed to
> the friction seal of a CGA, and with the DISS it is also assured you get a
> higher purity purge gas which lowers the moisture content of the nitrogen.
> ****
>
> ** **
>
> 4. Make sure you get UHP grade spec gas and nitrogen, as the purity is
> higher therefore the moisture is lower.****
>
> ** **
>
> 5. Keep your cylinders, as well as your gas cabinets, in a climate
> controlled room. You're in New York, so if you leave your cylinders in a
> cold room and hook them up to a warm system, you'll have an issue with
> moisture.****
>
> ** **
>
> 6. Make sure you have a dedicated purge cylinder per gas cabinet. Don't
> connect all the cabinets to a house purge or 1 purge bottle. The reason is
> the potential of contaminating your N2 if you lose a check valve and back
> stream spec gas into your N2 supply. ****
>
> ** **
>
> Note: If you have a contaminated gas line, you will most likely first see
> it in the regulator. The pressure will begin to "creep" and the regulator
> won't shut off. This is because moisture falls out at the pressure drops,
> and corrosion starts to build on the poppet at the seat interference area,
> on the diaphragm and downstream of the seat. Replacing the regulator won't
> help as your line is contaminated. At this point you would have to rebuild
> your gas panel, and quite possibly your gas line to the tool.****
>
> ** **
>
> These are a couple of ways that you keep you system clean and moisture
> free which allows your gas systems to stay trouble free. If you need any
> direct help, please let me know. I'd be happy to help wherever I can.****
>
> ** **
>
> Best to you sir, and good luck. I hope this helps.****
>
> ** **
>
> Tom Britton****
>
> Sales Manager****
>
> Critical Systems, Inc.****
>
> 7000 W. Victory Road****
>
> Boise, ID 83709****
>
> Direct: 208-890-1417****
>
> Shop:   877-572-5515****
>
> www.criticalsystemsinc.com****
>
> ** **
>
> *"World Leader in UHP Reconditioned Gas*
>
> *   Delivery & Abatement Technologies"*
>
> ** **
>
> ** **
>
> ** **
>
> *From:* labnetwork-bounces at mtl.mit.edu [mailto:
> labnetwork-bounces at mtl.mit.edu] *On Behalf Of *Bruce Tolleson
> *Sent:* Thursday, February 21, 2013 11:26 AM
> *To:* LABNET MIT
> *Subject:* [labnetwork] Gas delivery cylinders and lines****
>
> ** **
>
> Dear Labnetwork,****
>
>   What replacement cycles or life time expectancies do you have in place
> for bottled gasses and delivery lines, specifically for corrosive gasses
> like Cl2 and BCl3?****
>
> ** **
>
> Bruce E. Tolleson****
>
> Rochester Institute of Technology****
>
> 82  Lomb Memorial Drive, Bldg 17-2627****
>
> Rochester, NY 14623-5604****
>
> (585) 478-3836****
>
> [image: http://www.rit.edu/~962www/logos/tiger_walking_rit_color.jpg]****
>
> ** **
>
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>
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