choice of water for water cooled helium compressor

From: Phil Dennison (dennison@uci.edu)
Date: Wed Jan 02 2008 - 15:32:57 PST

Dear all,

If you have a cryoprobe with a water cooled helium compressor, I am
interested in what kind of water you use.

I have a Thermo Neslab heat exchanger which interfaces with our
building cooling water. The important thing is what kind of water is
in the closed loop between heat exchanger and helium compressor.

I previously used de-ionized water, but am replacing the helium
compressor due to poor water flow. I am told that de-ionized water
can dissolve the copper tubing, and indeed my plastic tubing shows a
thin coppery green coating.

One suggestion is to use tap water as long as it satisfies the
specifications for pH and solids content. In order to avoid all that
testing I am wondering if a good solution is simply to buy some
supermarket spring water, or other purified water. I only need about
8 litres to fill the system, so cost would be very low.

Does anyone have any advice on this?

Thanks,

Phil. 

-- 
Dr Phil Dennison
NMR Facility Director			(949)824-6010 (office)
Department of Chemistry			(949)824-5649 (lab)
University of California, Irvine	(949)824-8571 (fax)
Irvine, CA 92697-2025			dennison@uci.edu
USA

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