Infrared detectors of gas
Strips of absorption of many combustible gases are in the infrared range of an electromagnetic light spectrum, and the principle of absorption in infrared area is used already many years as laboratory analytical means. The infrared detector of gas belongs to low-power and compact type of the equipment used for industrial detectors of gas. These sensors have several advantages in comparison with catalytic type. They are characterized by very high speed of a response - less than 10 seconds, low operational costs and the simplified control thanks to function itself of diagnostics at the modern equipment with microprocessor management. They can also be tolerant to any known "poisons", failure-safe and will successfully work in the inert atmospheres and in the wide range of temperatures, pressure and humidity of environment. The principle of operation of the sensor of gas of this kind is based on absorption of two lengths of waves in the infrared range when light passes through sample mix with two wavelengths, one of which is established on peak of absorption of the defined gas, and another is not present. Two light sources pulse alternatively each other, directing light on a usual optical path that it left through explosion-proof "window" and then passed through sample gas. Bunches of beams then are reflected by a retro a reflector and again come back through a sample to the device. The detector compares force of a signal of beams of a sample and standard and by subtraction defines concentration of gas.