What is an ozone meter?
Description and Application.
The detector uses a thin-film semiconductor sensor. A thin-film platinum heater is formed on one side of an alumina substrate.
A thin-film platinum electrode is formed on the other side, and a thin-film semiconductor is formed over the platinum electrode by vapor deposition. The semiconductor film, when kept at a high temperature by the heater, will vary in resistance due to the absorption and decomposition of ozone. The change in resistance is converted to a change of voltage by the constant-current circuit.
The measuring range of the instrument is 0.01 ppm to 9.5 ppm ozone in air. The readings are displayed on a liquid crystal display that reads ozone concentrations directly. The temperature range is 0°-40° C, and the relative humidity range is 10%-80% RH.
Calibration.
Calibrate instrument before and after each use. Be sure to use a well-ventilated area since ozone levels may exceed the PEL for short periods. Calibration requires a source of ozone.
Controlled ozone concentrations are difficult to generate in the field, and this calibration is normally performed at SLTC. Gas that is either specially desiccated or humidified must not be used for preparing calibration standards, as readings will be inaccurate.
Special Considerations.
• The instrument is not intrinsically safe.
• The instrument must not be exposed to water, rain, high humidity, high temperature, or extreme temperature fluctuation.
• The instrument must not be used or stored in an atmosphere containing silicon compounds, or the sensor
will be poisoned.
• The instrument is not to be used for detecting gases other than ozone. Measurements must not be performed when the presence of organic solvents, reducing gases (such as nitrogen monoxide, etc.), or smoke is suspected; readings may be low.
Maintenance.
The intake-filter unit-Teflon sampling tube should be clean and connected firmly. These should be checked before each operation. Check the pump aspiration and sensitivity before each operation.
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