Dear All,
Our two spectrometers are on the ground floor of a building with 4
levels. Basement, Ground, floors 1, 2, and 3. There is a 4th floor but
the airlines do not go there. The building was built in the 1960's.
The compressor is a single unit by Ingersol-Rand and is sited in the
basement. Compressed air is reticulated using cast iron pipes. There
are several 'risers' feeding the floors and (semi) horizontal feed
lines supply the labs where short "risers" supply the benches.
Both instruments have water traps. Occasionally the traps are close to
overwhelmed. I wonder if any of you have encountered this situation
and found some solution. The compressor, in the course of its work,
may produce liquid water according to the Ideal Gas Law where n (moles
of vapour) = PV/RT. Ythis liquid accululated in the compressor's
ballast tank and is automatically expelled. Compression will also heat
the air, and when this compressed air cools again, some moisture will
come out of 'solution' and this is also drained from the ballast
chamber by an electronic system which detects liquid water and vents
it. The air under pressure delivered to the building will thus be
saturated. My theory is that the problem arises when compressed air is
drawn off on the upper levels. A leak on the upper levels might be a
major cause. As the air expands it cools and moisture is again
released. Now it accumulates in the pipework. If the horizontal feeds
are perfectly horizontal the water would flow down through the
pipework to the compressor and be vented. Otherwise it will accumulate
in the low-points of the system. A sudden demand at a lower building
level may 'sweep some of this moisture to the lower levels. If the
spectrometer happens to be in a "local minimum" on the pipework, the
water trap (manual and routinely emptied) is overwhelmed.
An electronic trap which vents any moisture every few hours sounds
like a possibility. It would have to be quick to avoid affecting the
sample temperature regulation.
I would appreciate your views and critique of my apmospheric physics.
Sincerely,
Andy
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Received on Fri Feb 13 2009 - 23:20:27 MST