TA Instruments TGA 2950 Operator's Manual page 238

Appendix D
NOTE:
D–4
The following description of the EGA furnace may
also be found in Chapter 4 of this manual.
The EGA furnace consists of a quartz glass
sample tube surrounded by an electric resistance
heater, both of which are contained within a
water-cooled furnace housing. The housing is
mounted to a furnace base that raises and
lowers the furnace for sample loading and
unloading.
The sample tube has a purge gas inlet that
passes through the right side of the furnace
housing. A fitting on the left side of the housing
allows connection of a transfer line to carry
exhaust gas to a spectrometer such as a mass
spectrometer. Because the heater is external to
the sample tube, evolved gases from sample
decomposition within the sample tube do not
come in contact with the resistance elements or
the furnace ceramic refractory.
Cooling air enters through the furnace base and
passes upward between the outside of the
sample tube and the inside of the furnace,
completely separating the cooling air from the
sample and the sample zone.
The furnace is a resistance heater wound on
alumina ceramic, which allows sample zone
temperatures as high as 1000°C with heating
rates up to 50°C/min.
A Platinel II* thermocouple is positioned in the
furnace, just above the sample pan, where it
monitors the sample environment temperature.
*Platinel II is a registered trademark of Engelhard
Industries.
TA I TGA 2950
NSTRUMENTS