B - 5
HAPSITE ER Operating Manual
Fittings on the Tedlar bags are typically 3/16 in. diameter; the inlet systems for the
HAPSITE are 1/8 in. diameter. Connection of the probe to the Tedlar bag can be
made with a stainless steel Swagelok type adapter, 3/16 in. to 1/8 in. The
recommended parts for this adapter include:
3/16 in. to 1/8 in. Reducer . . . . . . . . (Swagelok part# SS-300-R-2)
3/16 in. Teflon Ferrule Set . . . . . . . . (Swagelok part# T-300-Set)
1/8 in. Nut . . . . . . . . . . . . . . . . . . . . (Swagelok part# S-S-202-1)
1/8 in. Ferrule Set . . . . . . . . . . . . . . (Swagelok part# SS-200-Set)
The 3/16 in. O.D. tube on the Tedlar bag valve will slip into and out of the 3/16 in.
nut on the adapter, which can be easily finger tightened to seal, leak-free, on the
Teflon ferrule set. Care should be taken to not completely unscrew the 3/16 in. nut
from the adapter each time a Tedlar bag is removed. This will prevent the dropping
of nuts and ferrules. The 1/8 in. end of the adapter is a swaged connection to the
1/8 in. male Swagelok fitting on the end of the HAPSITE ER probe, so wrenches
will be required to make a leak free connection.
The Tedlar bag valve should be open only during the HAPSITE sample taking cycle
to save gas usage.
B.1.3 Gas Cylinder Safety, Contamination Checks, and Corrective Steps
Safety of operations should always take precedence in
the working environment. Gas cylinders should be
properly affixed to lab benches with clamps, or chained
to the wall for safety. A safety certified gas cylinder cart
should be available in the vicinity of where the cylinders
are normally used, for moving them and replacing empty
cylinders. Gas cylinders should never be transported
with the regulator attached!
Tedlar bags may be cleaned for reuse, or replaced with new bags. To clean a Tedlar
bag for use with different VOC's or concentrations, partially fill with VOC-free N
2
or
VOC-free air, heat it to 40-50°C by wrapping the bag with an electric blanket for
several minutes, then evacuate the bag contents through the open valve with a
clean transfer line to a diaphragm vacuum pump. This operation should be
repeated 10 times for a normal cleaning. Then the bag may be stored filled with
VOC free N
2
or VOC-free air until needed.
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