ECO PHYSICS, INC3915 Research Park Drive, Suite A-3 , Ann Arbor, , Michigan, United States

ECO PHYSICS, INC. was formed in 1995 as the US distributor for ECO PHYSICS AG of Switzerland. ECO PHYSICS has been offering sales support, training and service to our US customers from our offices in Ann Arbor, Michigan by our excellent team which includes 3 factory trained service staff. We stock all commonly required service parts and offer 24 hour turn around on service parts orders. Let us assist you with your NOx analyzer requirements.

We think of ourselves as innovative and application-orientated professionals who offer our clients total solutions. All our instruments undergo strict quality-control testing. Do talk to our specialists and get their professional advice. We look forward to hearing from you.

 Chemiluminescence NOx Analyzers rely on NO2 converters to provide a reading of total NOx, or NO + NO2. These converters last an average of 10,000 hours or about one year of continuous operation. As the converter loses its ability to convert NO2, the instrument will measure a lower percentage of the NO2 in your sample stream and provide a less accurate NOx value. The converter efficiency can be tested with a cylinder of NO2, however NO2 standards are known to have a short shelf life. The alternative method approved by the EPA is the Bag Test Method in section 16.2 of method 7E. This method, used by ECO PHYSICS, only requires a Tedlar bag, the same stable NO standard used for instrument calibration, and a source of ambient air (or other gas containing at least 19.5% oxygen).
The test involves filling half the Tedlar bag with NO, half with the compressed air and then immediately placing the bag on the analyzer sample inlet for a test lasting 30 minutes. You record the initial NOx value and then measure the NOx after 30 minutes. During this time NO is reacting with Oxygen (O2) in the bag to form NO2—however the total NOx concentration in the bag stays the same. If the final NOx measurement has decreased by more than 2% the converter has failed to meet specification. Converter efficiency testing is the best way to ensure your analyzer is providing an accurate NOx value in your measurements.