Wow. I had no idea this happens to everyone. I got 40 responses. In my
case, it happened because after my last He fill, I removed the latex
tubing connecting the 2 N2 exits too soon. The main points of the
responses:
1. Use L-shaped metal tubing to prevent it from dropping into the N2
can.
2. Use metal which is not attracted to a magnet.
3. Use N2 gas. Heat it somewhere on the metal tube away from the magnet.
It still takes forever.
4. Close the unblocked N2 exit, and put the spring loaded relief valve
on the N2 entrance.
Two responders were concerned about O2 molecules in the solid H2O which
might drop into the liquid N2, and their effects on the shims.
Thank you all very much, Bob Honeychuck
Original posting:
-------------------------------------------------------------------------------
> Subject: Blockage
> Date: Mon, 11 Mar 2002 17:15:23 -0500
> From: Robert Honeychuck <rhoneych_at_gmu.edu>
> To: ammrl_at_chemnmr.colorado.edu
Our Spectrospin Bruker 300 MHz 52 mm magnet has developed a blockage
which I assume is due to solid H2O in one of the N2 exits. The other N2
exit is not blocked, and the N2 entrance is not blocked. I haven't tried
to pressurize the N2 can or poke through the ice, deciding instead to
ask if any of you have solved this problem before. I don't know what the
inside structure is in the region where I am guessing the blockage is,
so I am reluctant to poke at it.
Thank you very much.
Bob Honeychuck
George Mason University
Received on Fri Mar 22 2002 - 11:23:43 MST