Inficon HAPSITE Smart, Operating Manual

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HAPSITE Smart Operating Manual
The smaller "leg" of the sampling tee is coupled to the HAPSITE. The total flow to
the sampling tee should be approximately 1 liter/min. to allow sufficient excess over
the HAPSITE sampling flow rate which is approximately 200 cc/min. and to prevent
external air from being drawn back into the vent "leg" of the sampling tee which
would alter the concentrations delivered from the cylinder or mixer.
B.1.2.2 Inert Sample Bag
Ultra clean Tedlar sample bags, dedicated to a given VOC compound
mix/concentration level, will be the most economic option for regular calibration
(more than once a week) and eliminates the waste of certified gas mix out of the
sampling tee vent. The dedicated Tedlar bag can be filled directly from the
associated gas cylinder or gas mixing system effluent.
WARNING
Regulate the gas delivery to avoid overfilling the bag.
Alternatively, a bag can be filled by delivery of a set volume of the diluent gas (via
a mass flow meter), then adding a set volume of the certified cylinder VOC gas mix,
followed by mixing to homogeneity in the bag to obtain the proper dilution. A 12-liter
Tedlar bag will allow about 60 HAPSITE samplings of the contents between refills.
The use of properly filled Tedlar bags inherently assures that the gaseous contents
are at atmospheric pressure for sampling. A properly filled Tedlar bag will have
plenty of flex left in the bag walls so that the bag can be easily kneaded to mix the
contents. The bag should not be filled to the point where the bag appears like a firm
"air pillow", as the bag would then be at above atmospheric pressure, and could
not be sampled accurately by the HAPSITE. In addition, this would lead to eventual
leakage along the bag seams, destroying the integrity. The use of straight through
on-off valves on the Tedlar bags (such as on 231 -XX series bags by SKC
5
, Inc.)
should minimize any flow restriction variation in gas delivery to the HAPSITE and
are preferred.
Clean Tedlar bags to be filled with a certified gas mix should be filled once with the
gas mix and allowed to stand several minutes for preconditioning, then evacuated
with a transfer line and a diaphragm vacuum pump and refilled again with the mix.
Fittings on the Tedlar bags are typically 3/16" diameter; the inlet systems for the
HAPSITE are 1/8" diameter. Connection of the Hand Control Unit (or the Heated
Line) to the Tedlar bag can be made with a stainless steel Swagelok type adapter,
3/16" to 1/8". The recommended parts for this adapter' include:
5.SKC: (800) 752-8472