Smoke and Chemical Sensors: 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 the control of environmental pollution both atmospheric and ground but is also used in process control applications to detect the presence, absence, or levels of impurities in processing chemicals.
Smoke detectors and heat sensors (automatic sprinklers) are now commonplace in the industry for the protection of people, and equipment, and for monitoring and control of chemical reactions.
This article will help you understand and become familiar with other sensors that play a very important part in process control, but may not be encountered on a daily basis. The following are covered in this chapter:
■ Position, distance, velocity, and acceleration sensors
■ Rotation sensors using light and Hall effect sensors
■ Force, torque, load cells, and balances
■ Smoke detectors, gas, and chemical sensors in the industry