Recent Excerpt:
Our biggest issue is that we run water as a solvent and if the power fails
Bruker turns off the VT air flow and that can lead to freezing a sample in
the probe which might crack the tube. Bruker sells a board for $10K that
solves this but that is too much for us to spend on this and I personally
feel it is such a foreseeable problem the board should have been included
with the initial purchase, particularly when the probe is designed for
protein work.
The other risk when running water as a solvent is loss of compressed air
supply. Bruker uses some pneumatically driven valves in the platform and
below 55 psi they may cut out and force a warmup.
I have put some significant effort towards developing a work around and
think I can do so for about $500 in parts but have not completed the design
yet.
Hey Cryoheads,
We have these same Bruker Cryoprobe issues here, and have implemented some
simple, inexpensive solutions that I'm willing to share. We are fortunate
enough to have an outage-proof house N2 gas supply, but this will work with
any backup air or N2 gas supply from a cylinder or LN2 gas pack.
The first device is an automatic air/N2 switchover to change the
spectrometer's gas supply to house N2 gas if the conditioned NMR air
pressure drops, or if the power goes out. The unit has a switch to manually
select N2 gas for VT work. I haven't built one lately, but I'm sure the
parts cost < $500. The major parts are a 3-way solenoid valve and a
pressure-actuated switch. We have these on several spectrometers, both
Bruker and Varian.
The second device is a solenoid valve to bypass the Bruker VT controller if
power goes out. It is also a 3-way valve, supplying the probe VT port from
the console VT controller when power is up. When power is out, the probe VT
port is supplied directly from the spectrometer air supply, through a needle
valve set to allow approx. the same flow under both conditions. Parts cost
~$150. This is only installed on the spectrometer with a Bruker Cryoprobe.
Feel free to contact me off-list for more details.
Cheers,
Jerry Hirschinger, NMR Instrumentation Specialist
Purdue Interdepartmental NMR Facility
560 Oval Dr. West Lafayette, IN 47907-2084
Office: Wetherill 365A
Phone / Fax: (765) 494-5288 / 494-0239
Cellular: (765) 427-3034
Received on Thu Jul 27 2006 - 17:54:02 MST