The plant produces cigarette filter material, using 22 dryers to remove acetone from the fibrous filter material through evaporation. Ductwork carries away the acetone laden vapors at 800 to 2000ft/min airflow velocity and a normal 140oF operating air temperature, rising to 300oF during steam cleaning.
A complex gas sample extraction system was first considered, but the combination of Pointwatch IR hydrocarbon detectors in Q810 enclosures, which mount directly to a flat duct surface, proved to be an all-round better and more cost-effective choice. Some 24 systems were required.
Considerably less expensive and easier to maintain, as well as simpler to install and reportedly more reliable than vacuum pump driven extractive systems, the enclosure's external mounting provides easy sensor access for inspection and calibration.
Accuracy was proven in evaluation testing by Hoechst Celanese. Monitoring a cross-section of duct airflow as opposed to point only, this system allows gas detection where direct sensor Detector Electronics Corporationn is not practical.
Duct air velocity drives the air sample into upstream air inlet tube holes and into the enclosure, where the factory-installed sensor measures gas concentration and provides an output signal. Downstream sample dump tube returns air to the duct.
The Q810 enclosure can be fitted with any Det-Tronic gas sensor to provide a detection system within air handling, heat/cooling and ventilating or exhaust ductwork of 1 to 10ft size. Acceptable air velocity range is 600 to 4000ft/min.
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