[Hallb-engineering] DC-gas alarms

David Anderson dla at jlab.org
Fri May 19 07:49:59 EDT 2017

To follow-up Morgan's question, I would like to propose a manual of sorts be prepared with all the drawings, possible alarms and proper responses
required to deal with each alarm state.
We are flying blind without reference material......


----- Original Message -----
From: "Morgan Cook" <mcookiv at jlab.org>
To: "George Jacobs" <jacobsg at jlab.org>
Cc: "Hallb-eng" <hallb-engineering at jlab.org>, "dsg-dc" <dsg-dc at jlab.org>
Sent: Friday, May 19, 2017 7:37:52 AM
Subject: Re: [Hallb-engineering] DC-gas alarms

Where can I find the drawings of the dc gas system?  

On Friday, May 19, 2017 6:58:48 Krister Bruhwel wrote:


Thanks George.  Just to clarify, changing dewars is a day time 
activity and should be regularly checked before leaving for the 
evening and weekend.  With the exception of the holidays and failures, 
the on call shouldn't be concerned with it.  Someone please correct me 
if I'm wrong, but this is the way I remember it from before. 


On Thu, May 18, 2017 at 05:02:51PM -0400, George Jacobs wrote:
>    There were a couple of issues;
>    -> Transducer Failure
>        There was a hihi alarm for mix#1 storage tank. The problem
>    associated with too high a pressure in the tank is typically, that the
>    CO2 supply pressure is too low to flow the sufficient gas to produce a
>    10% CO2 in argon mixture. The mix#1 pressure transducer failed,
>    resulting in a rapidly changing signal that crisscrossed the alarm
>    sepoint, resulting in multiple alarms. I have installed a replacement,
>    and am waiting for the new signal to be set up in the cRio.
>    -> CO2 Pressure is too low to maintain 10% mix ratio.
>        CO2 dewars arrive with a variety of pressures, from pressure too
>    low to use as is, to some with pressure too high and already venting
>    from the relief valve. The DC Gas mixing system CO2 supply must be
>    monitored several times daily to insure proper mixing system operation.
>    If the CO2 pressure is too low, the 10% mix ratio will not be 10%. In
>    order to closely monitor the CO2 supply, I have installed a new
>    pressure transducer to monitor CO2 gas supply pressure to the MFCs.
>    There is a lolo alarm at 100 psi.  This alarm should be turned on.
>    If you get this alarm, the following actions are required.
>    1) Check that the CO2 supply pressure at the CO2 pressure regulator
>    outlet pressure gauge on the outside wall of the gas shed matches the
>    alarm value.
>    2) Check the CO2 gas supply valves are open on the connected dewars,
>    flex lines, and pressure regulator outlet valves
>    3) Check individual CO2 dewar pressures - carefully adjust the pressure
>    buildup valve to increase CO2 supply pressure (This takes several hours
>    to come to an equilibrium)
>    4) Replace empty CO2 dewars
>    5) Verify the CO2 pressure regulators on the gas shed wall are set
>    properly.
>    George
>    On 5/17/2017 5:43 PM, Denny Insley wrote:
> Hello all,
>    Krister gave me a call this evening because he was getting constant alarms fr
> om DC-Gas.  I logged in and took a look at
> things and found the #1 mixing tank pressure and the C02 before the MFC's in maj
> or alarm. Both #1 and #2 CO2 flow indicators
> show around 2lpm flow. Krister tried to call George, then talked to Bob. It was
> decided to wait till morning so I disabled both
> alarms in the alarm handler so Krister could keep the phone on.
> Denny
> _______________________________________________
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> [1]Hallb-engineering at jlab.org
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> --
> George Jacobs
> Jefferson Lab (TJNAF)
> STE 12
> 12000 Jefferson Ave.
> Newport News, VA 23606
> (office) 757-269-7115
> (cell)   757-876-0480
> (email) [3]jacobsg at jlab.org
> (website) [4]https://userweb.jlab.org/~jacobsg
> References
>    1. mailto:Hallb-engineering at jlab.org
>    2. https://mailman.jlab.org/mailman/listinfo/hallb-engineering
>    3. mailto:jacobsg at jlab.org
>    4. https://userweb.jlab.org/~jacobsg

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 Krister Bruhwel : Jefferson Lab : (757) 269-7868 
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