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Paramagnetic O2 Purity Analyzer
Operational Theory
2.1 Introduction
The analyzer is composed of three subsystems:
1. Paramagnetic Sensor
2. Sample System
3. Electronic Signal Processing, Display and Control
The paramagnetic sensor and the sample system are located in the
Analysis Unit while the Electronic Signal Processing, Display and Control
systems are housed in the Control Unit.
The sample system is designed to accept the sample gas and transport
it through the analyzer without contaminating or altering the sample prior
to analysis. It is described in detail in Part II Section 6.4 of this manual.
The Analysis Unit is separate from the Control Unit in order to
provide critical temperature stability. The paramagnetic sensor is an
electromechanical device that translates the amount of oxygen present in
the sample into an electrical signal. It is a partial pressure device sensitive
to both operating pressure (vent pressure) and temperature fluctuations.
The output from the sensor is compensated for pressure variation using a
baseline pressure initially set during calibration. Temperature at the sensor
is held constant using an 80 Watt heater controlled by a PID temperature
controller located in the Control Unit. Feedback from the sensor to the
PID controller is supplied by an RTD installed in the Analysis Unit. The
paramagnetic sensor is described in Part II Section 6.2.
The electronic signal processing, display and control subsystem
simplifies operation of the analyzer and accurately processes the sampled
data. The microprocessor controls all signal processing, input/output and
display functions for the analyzer. Figure 2-1 is a block diagram for the
Control Unit and Figure 2-2 is a block diagram for the Analysis Unit.
These diagrams indicate the functionality of each unit and the interaction
between them.
Teledyne Analytical Instruments
Operational Theory
19
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