Teledyne 3010PA - Split architecture percent oxygen analyzer - Manual (Page 62)

Part II: 2-1
Oxygen Analyzers Part II: Analysis Units
Operational Theory
2.1 Introduction
The Analysis Unit is composed of two subsystems: the Micro-Fuel Cell
sensor and the sample system.
The Micro-Fuel Cell is an electrochemical galvanic device that trans-
lates the amount of oxygen present in the sample into an electrical current.
The sample system is designed to accept the sample and calibration gasses,
select between them (in response to Control Unit signals), and transport the
gas through the analyzer—without contaminating or altering its composition
before it reaches the sensor.
The electronic signal processing, display, and control systems are
housed in the remote Control Unit, covered in Part I if this manual.
2.2 Micro-Fuel Cell Sensor
2.2.1 Principles of Operation
The oxygen sensors used in the Model 3010 series are Micro-Fuel Cells
designed and manufactured by Analytical Instruments. They are sealed
plastic disposable electrochemical transducers.
The active components of a Micro-Fuel Cell are the cathode, the anode,
and aqueous KOH electrolyte in which they are immersed. The cell converts
the energy from a chemical reaction into an electrical current in an external
electrical circuit. Its action is similar to that of a battery.
There is, however, an important difference in the operation of a battery
as compared to the Micro-Fuel Cell: In the battery, all reactants are stored
within the cell, whereas in the Micro-Fuel Cell, one of the reactants (oxygen)
comes from outside the device as a constituent of the sample gas being