Eco Sensors
Ozone Analyzer, Model UV-100
21
Division of KWJ Engineering Inc.
User Manual, Rev. 2.0
[email protected] or (800) 472-6626
APPENDIX E
Theory of Operation
The Eco Sensors Ozone Monitor is designed to enable accurate measurements of indoor ozone over a
wide dynamic range extending from a limit of detection of .01 ppm by volume (ppmv) to an upper limit
of about 1,000 ppm based on the well-established technique of absorption of ultraviolet light at 254 nm.
The Ozone Monitor is light weight (4.7 lb., 2.1 kg.) and has low power consumption (
≈
5 watt) relative to
conventional instruments and is therefore well suited for applications such as:
• Industrial hygiene monitoring where ozone may be present in the workplace.
• Control of ozone generators and systems.
• Research and quality checking of ozone emitting equipment.
• Monitoring high ozone concentrations such as process off-gassing.
Theory of Operation
Absorption of UV light has long been used for measurements of atmospheric ozone with high precision
and accuracy. The ozone molecule has an absorption maximum at 254 nm, coincident with the
principal emission wavelength of a low-pressure mercury lamp. Fortunately, few molecules found at
significant concentrations in the atmosphere absorb at this wavelength. However, interferences, such
as organic compounds containing aromatic rings, can occur in highly polluted air.
Hg Lamp
Temperature Sensor
Air Pump
Photodiode
Absorption Cell
Pressure Sensor
Solenoid Valve
Ozone
Scrubber
Air Inlet
Schematic Diagram of
UV-100
