Toll Free: (888) 892-0303 | Ph: (712) 722-0337 | Fax: (712) 722-1787
Two inexpensive technologies exist to detect ozone. They are electrochemical and heated metal oxide semiconductor (HMOS).
An electrochemical ozone sensor uses a porous membrane that allows ozone to diffuse into a cell containing liquid or gel electrolyte and the electrodes. When the gas comes into contact with the electrolyte, a change in electrochemical potential between the electrodes is produced. Associated electronic circuitry will amplify, and control the signal. The signal is proportional to the ozone concentration (partial pressure) and is displayed in PPM or PPB.
- very linear
- rapid response - around 1-2 sec
- excellent repeatability and accuracy
- limited temperature range and sensitive to changes in temperature
- humidity extremes can destabilize the sensor
- sensitive to EMF/RFI
- limited storage life (18-24 months)
- not accurate below 0.01-PPM
HMOS
A heated metal oxide semiconductor (HMOS) sensor works by heating a small platinum substrate to a 300-deg F temperature. At this temperature, the substrate is very sensitive to ozone. A proportional signal is sent to the electronics and displayed in PPM or PPB.
- more linear vs. electrochemical
- can detect PPB ozone levels - will go below 0.01 PPM
- good repeatability and accuracy
- slow start-up - can require 8-24 hour minimum warm-up time to heat element & burn off contaminants
- not an instantaneous response - around 1-2 minutes
- cannot tolerate any smoke from cigarettes - smoke requires a minimum of 24-hours to burn off - other airborne particulates must be eliminated
- cannot handle any VOCs [volatile organic compounds] as VOC sensors utilize the same technology
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Toll Free: (888) 892-0303
Ph: (712) 722-0337
Fax: (712) 722-1787