[labnetwork] LN2 Dewar filling controllers

[Bob Hamilton]

Keith Bradshaw,

I am about to install a Magnatrol 24V direct acting cryogenic fill valve 
on our fill station. We will preserve our manual shutoff valve and add a 
1-hour spring wound timer for fills. We've found fills times for our 160 
L cylinders takes about an hour given our bulk tank pressure of 40 psi 
and expect it to take longer, in the future, when we raise this 3000 
gallon tank from 40 to 80 psi (i.e. a larger "flash loss").

It is interesting to read about your experience. I have no experience 
with electronic direct acting cryogenic valves and bulk fills. I did 
consider a pilot-operated valve using the tanks N2 pressure as the 
motive force but I went for the simpler direct acting route using an 
electromagnetic valve.

Choosing 24V AC means I can run a cable to the fill station and avoid a 
110V hazard.

I'm not looking for any surprises so your warning is appreciated!

Bob Hamilton

Robert Hamilton

University of California at Berkeley

Microlab Facilities Manager

Rm406 Cory Hall

Berkeley, CA 94720-1770

510-642-2716

510-642-2916 (Fax)

510-325-7557 (Cell)

bob at silicon2.eecs.berkeley.edu <mailto:bob at silicon2.eecs.berkeley.edu>



On 3/25/2010 12:43 PM, Keith Bradshaw wrote:
>
> We had a LN2 electric valve stick during filling and are looking for a 
> better system.
>
> What do you use for filling the big LN2 dewars?  We are filling from a 
> 3,000 gallon tank.
>
> Cordially,
>
> Keith Bradshaw
>
> Keith Bradshaw
>
> 972-883-2099
>
> RL 10
>
> University of Texas at Dallas Clean Room
>
> NSERL building
>
>
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