Analytical Industries AII-2000 M Oxygen Analyzer - Manual (Page 11)

4.8 Mounting
Every analyzer and monitor is equipped with a male dove tail bracket and
triangular shaped thick metal wire stand secured to the rear of the enclosure.
Tripod Wire Stand
Secured between bumper feet on either side of the battery compartment is a
triangular shaped thick metal wire stand that is hinged under the dove tail
bracket secured at the opposite end of enclosure.
Unsnap the triangular thick metal wire stand from between the bumper feet
and pull it away from the enclosure to form a tripod which allows the device to
sit upright on any flat surface
Dove Tail Bracket
The male dove tail bracket is secured to the rear of the enclosure with two
screws. The 1” female dove tail pole bracket (HRWR-1075) is an optional ac-
cessory that is commonly found in medical applications. The v-shaped male
component simply slides into and out of the pole mounted female section.
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5 Operation
5.1 Principle of Operation
The AII 2000 Series Oxygen Analyzers and Monitor utilize an electrochemical
galvanic fuel cell type oxygen sensor of the type that is extensively used to
measure oxygen concentrations from 0% to 100% in gas streams. Oxygen, the
fuel for this electrochemical transducer, diffusing into the sensor through a gas
permeable membrane reacts chemically at the sensing electrode to produce an
electrical current output proportional to the oxygen concentration in the gas
phase. The sensor has an absolute zero meaning that when no oxygen is pre-
sent to be chemically reacted the LCD displays 00.0 oxygen.
The sensor’s signal output is linear over the entire range, remains virtually con-
stant over the specified useful life and drops off sharply at the end. The sensor
itself requires no maintenance and is simply replaced at the end of its useful life
like a battery. Inasmuch as the sensor is a transducer in its own right, its ex-
pected life is not affected by whether the analyzer is ON or OFF.
The relationship between the sensor’s signal and changes with the oxygen
concentration is both proportional and linear, thus allowing single point calibra-
tion. Other factors that can affect the signal output are described in Section 5.2
Application Considerations and Section 3 Safety Warnings which should be read
before use.
Historically, the expected life of galvanic fuel type sensors has been specified as
“in air (20.9% O
2
) at 25°C and 760mm Hg”. The actual life of any galvanic fuel
type sensor is inversely affected by changes in the average oxygen concentra-
tion, temperature and pressure it is exposed to during its useful life. For exam-
ple, the AII-11-60 sensor has a 60 months expected life in air (20.9% oxygen)
at 25°C and ambient pressure, however, in a 100% oxygen atmosphere the
expected life is 12.6 months [60mo/(100%/20.9%)].
AII 2000 Series Oxygen Analyzers and Monitors are battery powered by (2) AA
alkaline batteries and controlled by a state-of-the-art microprocessor. The bat-
teries provide enough power to operate the analyzer continuously for approxi-
mately 1,200 hours. Both devices utilize a membrane type keypad for users to
communicate commands to the microprocessor. The monitor is menu driven to
accommodate the alarm functions. The digital electronics provide features such
as system diagnostics, warning indicators, controls and an alarm capability for
continuous monitoring that enhance both safety and effectiveness. The design
criteria, quality program and performance features ensure reliable and accurate
oxygen measurements.
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