Teledyne T360 Manuel d'utilisateur télécharger pdf (Page 209)

Teledyne API Model T360/T360M Operation Manual Principles of Operation

207

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.

7.4.3. Optical Bench & GFC Wheel

Electronically, the Model T360’s optical bench, GFC wheel and associated

components do more than simply measure the amount of CO

present in the

sample chamber. A variety of other critical functions are performed here as well.

7.4.3.1. TEMPERATURE CONTROL

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

. To accomplish

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.

7.4.3.2. IR SOURCE

The light used to detect CO

in the sample chamber is generated by an element

heated to approximately 1100

C producing infrared radiation across a broad band.

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.

07272B DCN6552

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Teledyne T360 Manuel d'utilisateur Page 209