Teledyne 9700 - Flue gas analysis system - Manual (Page 10)

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General Information Model 9700
TELEDYNE BROWN ENGINEERING
Analytical Instruments
To protect the Micro-Fuel Cell against damage from low
ambient temperatures and reduce the range required of the
compensation circuit, the analyzer is equipped with a
thermostatically controlled heating system that will not permit
the interior of the instrument to drop below 85 deg F.
To eliminate inaccuracies accompanying the positive
temperature coefficient of the Micro-Fuel Cell, a specially
selected thermistor and network of precision resistors are
utilized to produce a negative coefficient of matching
characteristics .
The variable element (thermistor) in the compensation network
is physically located in the same assembly as the Micro-Fuel
Cell so that both devices are exposed to essentially the same
temperature conditions.
• Integral Sample Pump Control
Because the analyzer was essentially designed to measure the
oxygen content of flue gas, provisions for powering and
controlling an electrically driven accessory sample pump have
been built into the analyzer. Terminal strip connections as well
as protective fusing are provided. Pump power is controlled
through the same RANGE switch that controls analyzer power
(see Dwg. B-l0913).
• Modular Electronics
The analyzer is equipped with integrated circuit (IC)
semiconductor electronics. Components are mounted on a plug-
in printed circuit board, as are various optional electronic
features, i.e., alarms and converter. Printed circuit assemblies
are preset and adjusted for immediate replacement.