Calibration Photometer System - Thermo Scientific 49i Instruction Manual

Calibration
Equipment Required
Calibration Photometer
4-2 Model 49i Instruction Manual
1. Irradiate the air with an ozone generating UV lamp to convert nitric
oxide to nitrogen dioxide. Alternatively, pass air through Purafil® which
oxidizes nitric oxide to nitrogen dioxide and scrubs nitrogen dioxide.
2. Pass air through a large column of activated charcoal to remove residual
nitrogen dioxide, ozone, sulfur dioxide, hydrocarbons, and so on.
3. Pass air through a molecular sieve.
4. Pass air through a final particulate filter to remove particulates which
originate in scrubbing columns.
Note An important requirement for the calibration photometer operation is
that the zero air used to reference the photometer come from the same
source as the zero air used in the ozonator. This is to effectively cancel
impurities present in the zero air source.
A UV photometer calibration system which includes an ozone generator, an
output port or manifold, a photometer, and a source of zero air is required.
System
The Thermo Scientific Model 49i Ozone Photometric Primary Standard
satisfies the calibration photometer system requirement in a single
convenient package. In addition, the Model 49i can be modified to operate
as a calibration photometer by removing the ozone scrubber and plumbing
zero air into the common port of the ozone-free solenoid valve, as shown in
Figure 4-1. If the Model 49i is modified to operate as a calibration
photometer, it must be dedicated for calibration and not be used for
monitoring ozone at any time.
Thermo Fisher Scientific