User's Manual

Theory of Operation M400E Ozone Analyzer Operator’s Manual
11.2.3. PARTICULATE FILTER
The Model 400E 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 12-2.
11.2.4. PNEUMATIC SENSORS
11.2.4.1. 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 3-4).
11.2.4.2. 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 3-4).
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