The detection of smoke, radiation, and chemicals is of great importance in industrial
processing, not only as it relates to the safety of humans, and to the control of atmospheric
and ground environment pollution, but also is used in process control applications
to detect the presence, absence, or levels of impurities in processing
chemicals.
Smoke detectors and heat sensors (e.g., automatic sprinklers) are now commonplace
in industry for the protection of people and equipment, and for the monitoring
and detection of hazardous chemicals. Low-cost smoke detectors using infrared
sensing or ionization chambers are commercially available. Many industrial processes
use a variety of gases in processing, such as inert gases (e.g., nitrogen), to prevent
contamination from oxygen in the air. Conversely, gases or chemicals can be
introduced to give a desired reaction. It is necessary to be able to monitor, measure,
and control a wide variety of gases and chemicals. A wide variety of gas and chemical
sensors are available, and the Taguchi type of sensor is one of the more common