Theory of Operation T400 Ozone Analyzer Operator’s Manual
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13.2.3. PARTICULATE FILTER
The Model T400 Ozone Analyzer comes equipped with a 47 mm diameter Teflon
particulate filter with a 5-micron pore size. The filter is accessible through the front
panel, which folds down to allow access, and should be changed according to the
suggested maintenance schedule described in Table 11-1.
13.2.4. PNEUMATIC SENSORS
13.2.4.1. Sample Pressure Sensor
An absolute value pressure transducer plumbed to the outlet of the sample chamber is
used to measure sample pressure. The output of the sensor is used to compensate the
concentration measurement for changes in air pressure. This sensor is mounted to a
printed circuit board next to the internal pump (see Figure 3-5).
13.2.4.2. Sample Flow Sensor
A thermal-mass flow sensor is used to measure the sample flow through the analyzer.
The sensor is located in down stream from the absorption tube but upstream from the
critical flow orifice. This sensor is mounted to the same printed circuit board as the
pressure sensor (see Figure 3-5).
