Hello Sheng,
I usually only reply to the sender, but I'm sending this to the whole list because I just sourced and purchased a Pump-Out operator for my Bruker-provided Cryofab transfer lines... maybe this will save someone some time.
All you need is a good mechanical vacuum pump, and the appropriate Pump-out operator for the type of transfer line that you have.
If you have a recent Bruker magnet, then you probably received the flexible braided stainless steel Cryofab transfer line (What Cryofab calls a "Flex U-Tube" transfer line). These can be pumped down by acquiring their "1/2" Pump-out Operator". I recently bought one of these from Cryofab for $260.00, part number: OPE1/2-KF. The -KF specifies the KF-25 vacuum coupler for use with a standard If you use Part# OPE1/2 (without the KF), you will receive a pump-out operator that has a straight tube to which you can attach a vacuum hose directly.
You can see a photograph of this tool by scrolling down this page, look for "Pump Out Operator": http://www.cryofab.com/products/cryogenic-transfer-lines/liquid-helium-transfer-line-CFHT
Instructions for using this Pump-out operator can be found at: http://www.cryofab.com/manuals/Cryofab_pump-out_operator_.5_inch_instructions
I now have three of these Cryofab transfer lines from Bruker, so this was a good investment of $260.00... especially since I discovered one of my lines had lost all vacuum as I was pre-cooling to fill one of my 400MHz magnets!
If you have an Oxford magnet, you will likely have a "less flexible" Oxford transfer line. These have a pump-out valve normally closed with a HEX-nut. I belive Oxford provided a pump-out accessory for every one of their transfer lines delivered with a magnet. I have at least four of these, and they all work with any of my Oxford transfer lines. If you can't find one, give me a shout and I can send you one to use (but I'll need it back ;o).
If you have a Varian R2D2, the rigid transfer lines provided with those had a pump-out valve built-in to the transfer line because they were notorious for losing vacuum easily.
I hope this helps.
Best regards,
-Rich S.
---
Richard K. Shoemaker, Ph.D.,
Research Professor & Director, NMR Spectroscopy Facility
University of Colorado at Boulder
Phone: (303) 492-7062 Fax: (303) 492-5894
E-Mail: Richard.Shoemaker_at_Colorado.edu<mailto:Richard.Shoemaker_at_Colorado.edu>
Web: http://chemnmr.colorado.edu/rshoe
From: Cai, Sheng [mailto:sheng.cai_at_marquette.edu]
Sent: Thursday, August 4, 2016 3:03 PM
To: ammrl_at_ammrl.org
Subject: AMMRL: liquid He transfer line
Hi all,
Our liquid helium transfer line is losing the vacuum. Is there any vendor where we can re-vacuum it? Thank you very much.
Sheng
Received on Fri Aug 05 2016 - 08:17:22 MST