Dear Kurt,
I have been using cheaper red rubber tubing (3/8" x 1/8") from VWR
Scientific for the last several years. We never had any problem. You need
to follow some rules for using them:
- Pass liquid N2 slowly at the beginning, Let the tube freeze
slowly. Speed up flow after that.
- Do not pull the tube or move the tank when the tube is frozen
- Warm the tube up using hot air dryer if you are in a hurry, otherwise
give couple of minutes for the tube to soften
- keep another tube line ready and handy, in case one of the line breaks,
when you pull the frozen tube.
I instruct my student helpers once and they do not have any problem filling
liquid N2 in the dewars.
You can also buy transparent and more expensive teflon tubing for this
purpose. The cost is more and they hardly break. You can also watch the
liquid flowing.
Sandip
At 11:23 AM 10/18/2002 -0400, you wrote:
>All,
>
>I am forwarding the below request on behalf of a colleague of mine here at
>Lubrizol. I know that this has appeared before on AMMRL.
>
>We have been using thick black vacuum hoses to do our nitrogen fills since
>1984 and never have we seen one shatter sending pieces of frozen rubber
>flying in all directions. They do split occasionally but this recent
>occurrence was clearly a safety hazard that we do not want to encounter again.
>
>We appreciate any input into where we can find a metal nitrogen transfer line.
>
>Best Regards,
>Kurt
>________________________________
>Kurt Wollenberg(KFW) Phone:(440) 347-2026
>The Lubrizol Corporation Fax:(440) 347-4482
>Wickliffe, OH 44092 Mail:153B
>mailto:kfw_at_lubrizol.com http://www.lubrizol.com/
>
> -----Original Message-----
>From: Karabatsos, Julie
>Sent: Friday, October 18, 2002 10:30 AM
>To: Wollenberg, Kurt
>Subject: Search for LN2 transfer line
>
>Kurt,
>
>Here is what we are looking for;
>
>
>
>We are looking for a safe means of transferring liquid nitrogen from the
>dewar to the NMR during our weekly nitrogen fills. We have always used the
>thick black vacuum hoses, attached to the dewar with a clamp. This has
>worked fine, but periodically the hoses crack during a fill, and yesterday
>one actually shattered. We are hoping to find a metal transfer line
>similar to the helium transfer line. The line would have to be fitted with
>a tip at one end to connect with the dewar, and some sort of fitting at
>the other end to slide onto the nitrogen inlet port on the NMR. Does
>anyone have ideas where we can look?
>
>
>
>Julie F. Karabatsos
>
>The Lubrizol Corporation
>Phone: 440-347-2260
>fax: 440-347-4482
>email: jfka_at_lubrizol.com
PEACE
********************************************** Best
Wishes ******************************************
Dr. Sandip K. Sur
NMR Manager and NMR Application Scientist
Department of Chemistry
University of Rochester
Rochester, NY 14627-0216
Note: New Area Code 585
Tel: (585) 275-4705 (W)
(585) 586-7794 (H)
Fax: (585) 506-0205
Email: sur_at_chem.rochester.edu
Received on Mon Oct 21 2002 - 13:37:38 MST