[Dsg-mvt] MVT mixing.

[Amrit Yegneswaran]

just talked to george about why safety is not approving the MFC and the mix1 and mix2 buffer tanks in the hall. 
i don't have the reasons why they didn't approve, so find it puzzling because: 
the lower explosive limit for iso-butane is 1.8% vol. 
given the tot. vol. of isobutane in the buffer tank to the vol of the hall (anyone know the vol. of the hall?, i'm guessing about 50 mega liters), putting the tanks in the hall should not be an issue. 

if the concern is that in case of a failure of the mfc, all the gas from the outside tank could windup inside the hall (in my opinion"impossile") we could put a simple straightforward safety interlock. 

of course we have to set the buffer tanks in an ignition free area. 
we could consider the area near the truck ramp, now that the hall b techs don't smoke there. 

anyway, just a thought. 

glad to hear from george that the premix cylinders are expected tomorrow. 









From: "Brian Eng" <beng at jlab.org> 
To: dsg-mvt at jlab.org 
Sent: Thursday, January 11, 2018 1:58:15 PM 
Subject: Re: [Dsg-mvt] Mix 1 Setpoint 

Also, the full scale (which determines minimum flow) can be adjusted if need be. 

For that I would need to know what the maximum flow rate you'd need out of the Ar MFC. 

It can be set from 1391 - 2780 sccm, the min flow is 1.5% of that value, so 41.7 sccm as currently configured. 

I don't know if the MFC retains that value when switching gases, so we'd need to test that if you decide we should change the value. 

----- Original Message ----- 
> From: "Brian Eng" <beng at jlab.org> 
> To: dsg-mvt at jlab.org 
> Sent: Thursday, January 11, 2018 1:49:09 PM 
> Subject: [Dsg-mvt] Mix 1 Setpoint 

> Hi Maxime, 
> 
> The flow rate you guys are requesting is currently to low for the Ar MFC, so it 
> isn't flowing anything. 
> 
> I would suggest raising the FMT (or FTT) setpoint to something higher. 

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