[Dsg-dc] DC gas safety system

[Marc McMullen]

Just an update on this matter. We spoke with Bob Miller yesterday and he 
informed us that currently DC gas is flowing without the need for the 
solenoid  safety system. The gas is being exhausted through bubblers for 
passive pressure safety controls. The old solenoid controls system will 
not be used at this time. Hall B is planning the path forward on the use 
of the solenoid safety system, they may be switching to a logic based 
(either cRIO or PLC) system and they will inform the DSG of results of 
the decision in the future. In the mean time the DSG will come up with a 
cost estimate to upgrade the current solenoid controls, and a plan to 
integrate it into the gas system controls to provided monitoring.

Thanks,
Marc
On 5/25/2017 12:04 PM, Ed Folts wrote:
> Thanks you all for including me in the loop. I think it is a great 
> idea to build an updated version of this control box. Having said that 
> it must comply with the rules for non UL tested components as called 
> out in EHS&Q manual chapter 6200. I have talked to Chris Cuevas and 
> has agreed to have his group do the certification inspection. In order 
> for him to do that he will need to be kept in the loop of fabrication 
> beginning with the schematics. The fabrication should be supervised if 
> not accomplished by a qualified electrical worker.
>
> thanks again
>
> Ed
>
>
> On 5/24/2017 9:45 AM, Brian Eng wrote:
>> While I haven't looked at it in depth, off-hand I don't think we need 
>> to change the design; if it worked for CLAS6 that should be enough 
>> validation that the system is sound.
>>
>> What does need to be changed is the implementation: not having any 
>> wiring outside of the chassis itself, replacing grommets with 
>> connectors, adding serviceable fusing, and small things like 
>> switching from lamps to LEDs, etc.
>>
>> We'll start putting together a parts list for the new system.
>>
>>> On May 23, 2017, at 7:09 PM, Amrit Yegneswaran <yeg at jlab.org> wrote:
>>>
>>> marc,
>>> with regards to §2, highlighted, after much deliberation, i am of 
>>> the opinion that because of the exigent circumstances, cosmic tests 
>>> and noise source debugging, replacing the underrated cable with a 
>>> cable of adequate rating, was the right thing to do. however, i am 
>>> concerned about the compliance of this old system with current 
>>> safety requirements. one definitely does not want to encounter 
>>> hitherto unknown problems. so, notwithstanding the circumstances, 
>>> the system needs to be replaced as soon as possible.
>>>
>>> as we discussed at the meeting today, dsg could build a safety 
>>> system to replace the existing system; hall b technicians could run 
>>> the new cables (if needed).
>>>
>>> brian, please discuss the matter with george and come up with a 
>>> design; mindy will fabricate the needed parts, which marc and george 
>>> can install.  brian, george, and marc please provide a cost estimate 
>>> for the new system.
>>>
>>> amrit
>>>
>>> From: "Marc Mcmullen" <mcmullen at jlab.org>
>>> To: "dsg-dc" <dsg-dc at jlab.org>
>>> Sent: Tuesday, May 23, 2017 5:11:40 PM
>>> Subject: [Dsg-dc] DC gas safety system
>>>
>>> Hi Morgan,
>>>
>>> Brian and I have replaced the 24VAC source cables which run from the
>>> SFL3 gas safety system box, to the distribution box (small one with the
>>> barrier blocks). We have also removed the bad barrier block from the
>>> distribution and relocated the R1/2 solenoid power wires to the single
>>> barrier block.
>>>
>>> Brian calculated the total draw of the solenoids to be just under 6amps
>>> for R1/2, the new cable p/n rates it at 15A vs. 4.9A (rating for 18awg
>>> cable, which was replaced).
>>>
>>> We tested the solenoids with the safety system box in local mode. All
>>> were audibly verified. We left the supply flow at 0Lpm, as you 
>>> requested.
>>>
>>> Thanks,
>>>
>>> -- 
>>> Marc McMullen
>>> Detector Support Group
>>> 757-269-7738
>
>
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-- 
Marc McMullen
Detector Support Group
757-269-7738