Optical Bench & Gfc Wheel - Teledyne T360 Operation Manual

Teledyne API Model T360/T360M Operation Manual
7.4.3. Optical Bench & GFC Wheel
7.4.3.1. TEMPERATURE CONTROL
7.4.3.2. IR SOURCE
07272B DCN6552
corruption. In the unlikely event that the flash chip should fail, the analyzer will
continue to operate with just the DOM. However, all configuration information
will be lost, requiring that the unit be recalibrated.
Electronically, the Model T360's optical bench, GFC wheel and associated
components do more than simply measure the amount of CO
sample chamber. A variety of other critical functions are performed here as well.
Because the temperature of a gas affects its density and therefore the amount of
light absorbed by that gas it is important to reduce the effect of fluctuations in
ambient temperature on the Model T360's measurement of CO
this the temperature of both the sample chamber and the GFC Wheel are
maintained at constant temperatures above their normal operating ranges.
Bench Temperature: To minimize the effects of ambient temperature variations
on the sample measurement, the sample chamber is heated to 48C (8 degrees
above the maximum suggested ambient operating temperature for the analyzer).
The heat source is a strip heater attached to the underside of the chamber housing.
The temperature of the sample chamber is sensed by a thermistor attached to the
sample chamber housing.
Wheel Temperature: To minimize the effects of temperature variations caused by
the near proximity of the IR Source to the GFC wheel on the gases contained in
the wheel, it is also raised to a high temperature level. Because the IR Source
itself is very hot, the set point for this heat circuit is 68C. The heat source is a
cartridge heater implanted into the heat sync on the motor. The temperature of
the wheel/motor assembly is sensed by a thermistor inserted into the heat sync.
Both heaters operate off of the AC line voltage supplied to the instrument.
The light used to detect CO
heated to approximately 1100
This radiation is optically filtered after it has passed through the GFC Wheel and
the sample chamber and just before it reaches the photo-detector to eliminate all
black body radiation and other extraneous IR emitted by the various components
of those components.
in the sample chamber is generated by an element
2
o
C producing infrared radiation across a broad band.
Principles of Operation
present in the
2
. To accomplish
2
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