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Electrochemical vs. HMOS Ozone Sensing

Two inexpensive technologies exist to detect ozone.  They are electrochemical and heated metal oxide semiconductor (HMOS).

For further information, click through to this page on our new site:  HMOS vs. Electrochemical Ozone Sensors

Electrochemical Sensor:
 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.

Advantages:

bulletvery linear
bulletrapid response - around 1-2 sec
bulletexcellent repeatability and accuracy

Disadvantages:

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limited temperature range and sensitive to changes in temperature

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humidity extremes can destabilize the sensor

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more sensitive to EMF/RFI than HMOS

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limited storage life (18-24 months)

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not accurate below 0.01-PPM

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affected by chlorine gas

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.

Advantages:

bulletvery linear
bulletcan detect PPB ozone levels
bulletgood repeatability and accuracy

Disadvantages:

bullet

slow start-up - requires 8-24 hour minimum warm-up time to heat element

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not an instantaneous response - around 1-2 minutes

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cannot tolerate any smoke from cigarettes - smoke requires a minimum of 24-hours to burn off

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cannot handle any VOCs [volatile organic compounds] as VOC sensors utilize the same technology

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affected by chlorine gas

 

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See our New Site  www.ozonesolutions.com