[Hallb-engineering] Cryogenics Wednesday

David Kashy kashy at jlab.org
Mon Aug 23 13:56:56 EDT 2010

Hi Steve,
There will be an ESR down this Wednesday. Cryo wants us to go to Warm 
return between 5:30 and 06:00 Wednesday morning.

I suggest the following procedure.
Start at 5:40 8/25

1) Lock the buffer dewar supply valve (EV8210) in manual mode at 50% to 
limit the flow.
2) Open the buffer dewar back pressure valve (EV8210BP)100%
3) Close the Torus supply valve (EV1110) by 5% again to limit the flow
4) Slowly open the buffer dewar warm return valve (EV8210CD) to 100% 
while watching the pressure of the dewar and the torus they should stay 
below 1.3atm! If the pressures go up reduce the supply valve positions 
EV1110 and EV8210 if necessary the Torus warm return valve (MV1115) may 
be opened but I don't think it will help reduce the pressure much.
5) Protect all hardware in the hall from dripping water or ice by 
covering with plastic and putting catch buckets appropriately. Ice will 
start to melt after the ESR goes fully down.

We should get 4K helium back in the late afternoon.

Please contact me if you have questions or concerns.

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