TA Instruments TGA 2050, Operator'S Manual

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TA I
NSTRUMENTS
TGA 2050 3–17
Purge gas can be obtained from a pressurized
cylinder or an in-house supply source. Gas
supplied from an in-house source should be
passed through a sieve dryer to remove any trace
of moisture before in enters the TGA.
It is important to maintain the proper ratio of
flow rates between the balance chamber and the
furnace housing. Having the separate balance
chamber purge prevents decomposition gases
from entering the balance chamber. The recom-
mended setting for the purge rate is 100 cc per
minute or less. The flow distribution should be
10 percent to the balance chamber and 90
percent to the furnace.
To maintain this flow distribution, you will need
to connect a flowmeter to each of the purge
fittings on the back of the TGA instrument. Set
the purge gas flow rates by adjusting these
meters. The PURGE port goes to the TGA
furnace, and the BALANCE PURGE goes to the
balance chamber.
Before you start the purge gas, make sure that
the desired gas is connected to the purge ports,
that all lines are clear, and that your supply of
purge gas is sufficient for the experiment.
Always maintain constant purge flow rates and
distribution throughout your experiment;
changing the purge during an experiment can
affect the data.
Running an Experiment