[Hallb-engineering] [New Logentry] Follow-up Re: Hall B Cryogenic Problem - PLC/Comms/Blowing Reliefs

kashy at jlab.org kashy at jlab.org
Thu Sep 14 02:20:03 EDT 2017

Logentry Text:
Buffer Dewar put on warm return. Its current level is 49% 
RV8120 sealed itself after the pressure dropped due to 4K supply and return shutoff. 
I manually opened EV8670BY by lifting the actuator up ~0.2" to allow a bypass around the solenoid heat shield. This helped drop the pressure on RV8670 and I used the hair dryer (hot air gun) to melt the ice and get the relief to seal.

We should do the following ASAP
1) add a 30/30 gage to the guard vac pump line (PT8677)
2) Find and position the EV manual control box
3) Get a new on-call list to the guard shack (theirs is from 2012)
4) Determine how we will get 24/7 on-call support for PLC's of the new cryo system (both short and long term)!

We must:
1) remount EV8670BY before starting the cooldown

We should consider doing the following before starting the cooldown:
1) installing the new flow meters on the magnet warm return gas panel, this is not needed now and can wait for a future warm up of the solenoid, but if time allows it can be down now...

In the not to distant future we must:
1) make a drip tray around RV8670
2) make a drip tray around the Torus service tower
3) figure out how to get the guard shack involved in cryo alarms for Hall B. The automatic text/e-mail to cell phones is not sufficient! there were lots of mails/texts last night to phones including my own but the only reason I knew of this was a phone call to my home phone from a person. Thanks Jonathan Creel! He got the notice that there was a cryostat leaking in Hall B from the crew chief who got the message from a guy on the PSS team. Then the guard shack will be able to call down the list including home numbers until someone is reached!!!


This is a plain text email for clients that cannot display HTML.  The full logentry can be found online at https://logbooks.jlab.org/entry/3484401
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