I used a Neslab HX-150A refrigerated recirculator at the University of
Vermont from 1990-1994 with great success to cool the diffusion pumps of a
SIRA II, as well as to cool a small mercury diffusion pump on a
sulfide/sulfate/carbonate extraction line I built.  The recirculator was on
the opposite side of a fairly large lab from the mass spec.  I ran opaque
green garden hoses between the recirculator and the mass spec and between
the recirculator and the extraction line.  I split the flow between the
mass spec and the extraction line using a T-connector.  Connections at the
mass spec were secured by ordinary hose clamps.  I had the luxury of
running the hoses along small troughs below the floor level covered by
grates nearly flush with the floor that we had installed to drain away
spilled water, so that the hoses did not interfere with movement by
personnel around the lab.  Because of the considerable distance the
recirculated water traveled, I lowered the temperature of the outgoing
water a couple of degrees lower than normal.  I used a few drops of
algicide in the recirculator's reservoir, and that worked well to.
Maintenance was relatively minor and the manufacturer was close by in New
Hampshire.  Because the unit was air cooled, it contributed to increasing
the ambient temperature in the lab, but I took care of that with the air
conditioning that I would have installed anyway.  The noise level wasn't
too loud, but if one has the option of setting the recirculator up in
another room or outside of the building in some covered space, that would
be preferable.  Andrei Lini could tell you how the unit has functioned
since 1995.

Steve


>To all listmembers,
>
>Furthering the discussion about mains water cooling, we have
>tried this method in the past but experienced corrosion problems
>in the narrow bore copper tubing used to circulate water around
>the mass specs between the diff pumps, causing local flooding.
>If your water is metered, it is also an expensive option!
>
>We've found that chilled recirculators can improve a diffusion
>pump's performance compared with cooling by mains water which, in
>summer, is at a relatively high ambient temperature making it less
>efficient.  Interested to hear if this experience is shared by others.
>
>Thanks for all the suggestions and comments received to date.
>
>Mike Isaacs

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