Across the street over here at UCSD, we have a Balston/Whatman
air dryer (of the kind that is supposed to take the output air
down to a dewpoint of -70C) that supplies three 500s and a 600.
Three of the systems have Bruker BCU05's that run more or less
constantly. We have had no problems with the cooled air lines
icing up. Before we installed the Balston, the BCU05's would
ice up immediately, so we could only run the BCU05's with N2
instead of air. Our building air is very wet; we installed an
extra pre-filter ahead of its built-in pre-filters, with a large
bowl and a drain left permanently open as a bleed, to keep liquid
water out of the Balston. We did have a problem with the Balston
after it had been installed a few months, but that was caused by
one of its valves sticking, and manifested itself as the air
supply shutting off completely at random intervals. It's been
running more than a year since that was fixed with no further
problems so far.
As for your question about some way to check the moisture content of
the air - I haven't tried this, but if you could find a glass cold
trap (preferably of the kind where the coolant is contained in an
inner thimble) and put it in-line in your air stream, it might work
to gradually lower the cold-trap temperature until you observed
condensation; this should be a direct measure of the dew-point. Of
course, this couldn't be adapted to a continuous on-line measuring
device, if that's what you need.
John M. Wright, Dept. of Chemistry & Biochemistry, MS 0314, UCSD,
La Jolla, CA 92093-0314; jwright@ucsd.edu; (619) 534-3049
> From: John Chung <chung@scripps.edu>
> To: ammrl@bloch.cchem.berkeley.edu
> Subject: wet vt air
>
> howdy
>
> it's raining on the west coast, but i'm more concerned today about
> a sudden icing up of vt air chillers on our spectrometers, most
> likely caused by our compressed air being wet.
>
> i need some help/input into figuring out what to do about it.
[description of symptoms deleted........]
> since all signs seem normal and i'm not sure how to proceed,
> I'D LIKE TO KNOW IF ANYONE OUT THERE HAS A WAY OF "QUANTIFYING"
> THE AMOUNT OF MOISTURE IN YOUR COMPRESSED AIR.
> and by this i mean something i can rig up myself and not go
> and buy a fancy measuring device which for one would take too
> long...
>
> or if any of you have any suggestion on what to do other than
> running all vt off our nitrogen generators (which i have done for
> two of the machines for now), since the nitrogen generator itself
> is fed the same air and is probably not as dry as we'd like
> if indeed the inlet air is wet.
>
> thanks for your help.
>
> John Chung
>
> *************************************************************
> Manager, NMR Laboratories (619)784-7453 (Office)
> Dept. of Molecular Biology, MB2 784-7455 (Lab)
> The Scripps Research Institute 784-9822 (Fax)
> 10666 N. Torrey Pines Rd. email: chung@scripps.edu
> La Jolla, CA 92037 http://www.scripps.edu/~chung
> *************************************************************
>