Discovery TGA™ Getting Started Guide
Page 13
TGA System Components
The Discovery TGA is comprised of the following major hardware components:
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The Tru-Mass™ balance, which provides precise measurement of sample weight. The balance is the
key to the TGA system.
•
The heating system, or furnace (wire-wound for TGA 55 and TGA 550, infrared for TGA 5500),
which controls the sample temperature.
•
The Autoloader or Autosampler, which loads and unloads the sample to and from the balance. The
Autosampler platform has a built-in pan punching mechanism (standard on the TGA 5500 and optional
on the TGA 550) that is used in conjunction with the optional sealed aluminum pans (also standard on
the TGA 5500 and optional on the TGA 550).
•
The heat exchanger, which dissipates heat from the furnace.
•
The gas delivery module (GDM), which controls the purge gas to the balance and furnace.
The next few pages briefly describe the components of the TGA.
Balance Assembly
The TGA balance assembly is a null balance system consisting of the balance meter movement, the bal-
ance arm, the balance position sensor, the hang-down wire assemblies, the sample pan, and the tare pan.
•
The balance meter movement is a taut-band meter movement to which the balance arm is attached.
•
The balance arm is an assembly constructed of beryllium copper alloy attached to the meter move-
ment.
•
The balance position sensor is comprised of an LED source and a pair of photodiodes on printed circuit
boards that detect the null position of the meter movement.
The TGA has two hang-down wire assemblies: one for the tare pan and one for the sample pan. Each
assembly consists of a hang-down wire and beryllium copper decoupler loop. The hang-down wire has
hooks on each end used to connect the pan to the loop. The loop connects the hang-down wire to the
balance arm. The longer hang-down wire is for the sample side.
The tare hang-down wire, tare pan, and any counterbalance weight mechanically balances the weight of the
sample pan and sample hang-down wire.
