How to Measure Output of Commercial Ozone Generators

Test Performance of your Commercial Ozone Generator

Commercial ozone generators are sold all over the world from many manufacturers past and present. These ozone generators usually produce ozone from ambient air that is blown across a corona or UV device that produced ozone from the ambient air blown through the generator.

Ozone output is normally measured in mg/hr. To calculate mg/hr of ozone produced we must know the mass of ozone and the volume of air. These calculations along with the equipment and methodology required are listed below.

It is important to understand and realize that the quality of ambient air, temperature of the air, relative humidity of the air, and cleanliness of the UV light or Corona discharge device are very critical. As these parameters may change over time ensure you quantify and qualify each parameter before beginning this test. Also understand that manufactures of these ozone generators may not ever test ozone production, or may test production with a wide variety of ambient temperatures, relative humidities, and other factors.

 

Equipment required:

 An ozone meter will be required to measure ozone concentration in the air leaving the ozone generator. This must have a sample pump to draw a sample of gas from your flow tube into the monitoring device. This will provide the most accurate ozone measurements without disrupting your air flow. Ideally a UV based ozone analzyer will be used to measure ozone levels due the greater precision and accuracy available. However, there are some ozone meters available using electrochemical or HMOS sensor cells that can pull a gas sample into the sensor and provide reasonable accuracy. For the best accuracy in ozone production choose the most accurate ozone meter possible.

UV-100 Ozone Analyzer for sale or rent
UV-100 Ozone Analyzer

The specific ozone analyzer we recommend to use for this testing is the UV-100 Ozone Analyzer.  This is available for sale, or for rent for shorter term needs.

 

A Monometeris used to measure airflow by measuring the velocity of airflow in your flow tube. A digital monometer can be obtained that will measure airflow in a variety of units of measure. For the best accuracy in ozone production choose the most accurate monometer possible.

 

A Flow Tube must be constructed to measure airflow from the ozone generator. This tube can be constructed of PVC or other plastic materials. The airflow from the ozone generator must have as much turbulence removed as possible to accurately measure air speed. This tube must be sealed directly to the outlet of the ozone generator and must not restrict air flow in any way. Actual air flow of the ozone generator in normal operation must be obtained and measured accurately.

measure output of ozone generator
The illustration above provides an example of how to measure output of ozone from a commercial ozone generator using instructions provided here.

 

Units of measure:

For more information on common ozone related units of measure click HERE.

mg/hr = grams per hour – commonly used to measure output of commercial ozone generator. 1 mg/hr = 1,000 mg/hr ozone

ppm = parts per million – commonly used to measure ozone concentrations in ambient air. Can be measured by weight or by volume, most commonly is measured by volume, for the purpose of this article we are using only ppm by volume.

m3/min = cubic meters per minute = measurement of air flow from ozone generator

m/s = meters per second= measurement of air speed, monometer will measure air speed in m/s

 

Calculations:

Ozone production calculation:

mg/hr = (m3/min x 60) x (ppm x 2.14)

 Example:

  • 100 mm x 100 mm square flow tube (100 mm is about 4”)
  • 10 ppm ozone concentration
  • 5 m/s air speed in flow tube (5 m/s = 16.4 ft/s)

100 mm = 0.1 meters

0.1 x 0.1 = 0.01 m2

0.01 m2 x 5 = .05 m3/second

.05 x 60 = 3 m3/min

(3 m3/min x 60) x (10 x 2.14) = 3,852 mg/hr ozone production

Additional information:

How ozone is produced

How corona discharge ozone generator work

How UV lamp ozone generators work

White paper: Validation of Gas Flow Measurement Druing Ozone Generator Performance Testing

White Paper: Guideline for Measurement of Ozone Concentration in the Process Gas From an Ozone Generator

How to measure output of industrial ozone generators

Test performance of your industrial ozone generator

Ozone generator production is normally measured in g/hr or lb/day for these ozone generators. For more information on units of measure click here. This article will use g/hr for all calculations.

To determine the g/hr of ozone from an ozone generator we must determine the grams of ozone that are produced in a given hour period of time. This is done by determining the gas flowrate through the ozone generator and the concentration of ozone in that gas.

Concentration of ozone is normally measured in g/m3 or % by weight.

Equipment required:

  • UV Ozone Analyzer
  • Supply-gas flow-meter
  • Ozone gas flow meter
  • Ozone destruct device

A UV Ozone Analyzer is required to measure high concentrations of ozone accurately. The high concentrations of ozone produced by an industrial ozone generator can be measured accurately and reliably using a UV based ozone analyzer. The UV Ozone analyzer will measure ozone in either g/m3 or % by weight. This will provide the concentration of ozone gas produced by the ozone generator.

A Supply-gas flow-meter is any flow measurement device that is measuring the total oxygen or dry air supply-gas flowing through the ozone generator. This will measure the volume of gas and provide the total mass of gas to determine total ozone production.

The Ozone Gas flow-meter will regulate the amount of ozone gas flowing through the ozone analyzer. Most UV based ozone analyzer are rated for a gas flow rate of 1-2 LPM. Therefore when dealing with total gas flows greater than 2 LPM ozone gas flow must be diverted around the ozone analyzer and continue to the point of use. This ozone gas flow-meter will be used to control and regulate the ozone gas flow through the ozone analyzer.

The Ozone Destruct Device will be used to safely catalyze all ozone back to oxygen after the UV ozone analyzer. This will allow ozone to be measured in a safe environment.

 

The illustration below provides an example of how this equipment can be configured. This may be a temporary set-up to test an ozone generator, or be a permanent part of a large ozone system where confirming ozone production is imperative.

Measure output of an industrial ozone generator
How to measure output of ozone generator with ozone analyzer

 

Units of measure:

For more information on common ozone related units of measure click HERE.

G/hr = grams per hour – this is the most common measurement of ozone production.

Lb/day = pounds per day – this is a common unit of measure for very large ozone generators

wt% = percent by weight = common method of measuring ozone concentration by weight

g/m3 = grams per cubic meter = best method to determine ozone concentration by weight

 

Calcuations:

Your ozone analyzer may provide ozone concentrations in % or g/m3. Calculations for either are shown below. Only LPM is used to measure flow for convenience.

g/m3:

Ozone Output (g/hr) = ((LPM x 60) x 0.001) x g/m3

percent by weight using oxygen as a feed gas:

Ozone Output (g/hr) =(( LPM x 0.001) x 60) x(14.3 x % by weight)

percent by weight using dry air as a feed gas:

Ozone Output (g/hr) =(( LPM x 0.001) x 60) x(12.8 x % by weight)

g/hr – lb/day:

1 lb/day ozone = 18.89 g/hr ozone

 

Note:

When wt% is used to measure ozone concentrations, the calculation to determine ozone output is different between air and oxygen gas due the fact that density of the gas is different. This requires separate conversion calculations used to determine the output of an Ozone Generator (as shown above). Due to this reason we prefer to always use g/m3 when measuring ozone concentrations and ozone production.

Original and complete document found HERE

How to measure output of an ozone generator with an ozone sensor

Measuring Ozone Generator Output

Tech note from EcoSensors

We have sold many instruments for testing ozone generators either when they are manufactured or at the customer’s site. Most popular for this is our A-21ZX because of its 0-10 ppm range. Our new UV-100 ozone analyzer using the ultra violet absorption principle will measure over the 0-100 ppm which will be suitable for measuring the output of most smaller ozone generators. The UV-100 can log the data for playback and analysis at a later time, and it can send the data directly as it is sensed to a PC.

A-21ZX
UV-100 ozone analyzer
UV-100

It is key to realize that the output of ozone generators is almost always measured in grams per hour whereas ozone instruments measure concentrations in parts per million. To relate these two mathematically, you need to know the generator’s air flow rate in cubic meters per minute. The formula is:

Output (g/hr) = .128 X air flow(m3/min) X concentration(ppm).

= .00364 X cfm X ppm in cubic feet per minute units

For typical small generators, such as for room air “purification,” outputs of 1/10-1/2 gram/hour are used. For their air flow rates, our A-21ZX will reach its 10 ppm maximum reading at 1/2 gram per hour or a little less (from which we can deduce that the air flow rate is typically 3-4 m3/min which is indeed typical for equipment blowers). The easiest way to get the air flow rate is from the label on the blower.

The concentration of ozone declines rapidly as the measurement distance increases from the generator. Ozone that reads 10 ppm right at the output grill rarely exceeds .1 ppm 1 meter from the generator.

Information obtained from EcoSensors Tech Support