Principles of Operation Teledyne API T703/T703U Calibrator Operation Manual
200
O
3
Generator Temperature Control 9.5.3.1.
In order to operate at peak efficiency the UV lamp of the O
3
generator is
maintained at a constant 48ºC. if the lamp temperature falls below 43ºC or rises
above 53ºC a warning is issued by the CPU.
This temperature is controlled as described in the section on the relay PCA (see
Section 9.2.3.2). The location of the thermistor and heater associated with the O
3
generator is shown below:
O
3
Generator
Heater Control PCA
(Heater is located beneath
the PCA)
Figure 9-17: O
3
Generator Temperature Thermistor and DC Heater Locations
9.6. PHOTOMETER OPERATION
The calibrator‟s photometer determines the concentration of Ozone (O
3
) in a
sample gas drawn through it. Sample and calibration gasses must be supplied at
ambient atmospheric pressure in order to establish a stable gas flow through the
absorption tube where the gas‟ ability to absorb ultraviolet (UV) radiation of a
certain wavelength (in this case 254 nm) is measured.
Gas bearing O
3
and zero air are alternately routed through the photometer‟s
absorption tube. Measurements of the UV light passing through the sample gas
with and without O
3
present are made and recorded.
Calibration of the photometer is performed in software and does not require
physical adjustments. Two internal variables, a slope and offset are used to adjust
the calibration of the photometer.
The CPU uses these calibration values, the UV absorption measurements made
on the sample gas in the absorption tube along with data regarding the current
temperature and pressure of the gas to calculate a final O
3
concentration.
MEASUREMENT METHOD 9.6.1.
Calculating O
3
Concentration 9.6.1.1.
The basic principle by which photometer works is called Beer‟s Law (also
referred to as the Beer-Lambert equation). It defines the how light of a specific
To Next Page
Loading...