We got one from Haskris, sort of through Varian (was included in the
purchase price, we just had to get together with Haskris so they could
build a unit to match our building's secondary chilled water flow rate and
temperature). One problem we didn't forsee is that the pumps for our
building 2ndary chilled water aren't on emergency power, so when our
building undergoes a power outage, the Haskris unit shuts itself off when
its compressor heats up. The thermal limit of the Cold Probe's helium
compressor is then reached, and the Cold Probe initiates warmup. Near as
we can tell, this takes about 10 minutes. We've invested a lot of money
in UPSs for all the electronics, so this is kind of an Achilles heel for
us. We're trying to get our facilities people to put the pumps on
emergency power, but mucho $$$. For awhile, even short outages (less than
10 seconds, so the building's emergency generators didn't even kick in)
would cause the Cold Probe to shut off, but after talking to Haskris, they
told us that the reset on their unit's compressor is set by default to
"manual" in the factory; once we shifted it to "automatic" we were able to
survive these shorter outages without incident. The water-cooled Haskris
units work very well, but if you don't have uninterrupted chilled water
feeding them, you may have some "unscheduled" probe warmups whenever you
lose water. If the air-cooled works for you (needs only power, but really
pumps out the heat), it might be a better bet. Hope some of this helps
you.
Sean
On Mon, 16 Oct 2006, George T. Furst wrote:
> Hi Folks:
> We just got funding for a new cryoprobe and our wondering what current
> users are using for water chillers for the helium compressor , we cannot use
> an outside one due to university restrictions. .
>
> Thanks
> George
>
>
--
Sean Moran
Bio-NMR Facility Manager
Dept. Biochem. & Cell Biol.
Rice Univ.
Houston, TX 77005
(713)348-3475 (lab)
(713)348-4255 (off)
(832)398-4208 (cell)
(713)348-5154 (fax)
seamus_at_rice.edu
Received on Wed Oct 18 2006 - 09:55:32 MST