Principle of Fibre Optic Infrared Thermometer
Fiber optic infrared thermometer is a type of infrared thermometer. Also called fiber optic sensing thermometer, the main principle of ordinary infrared thermometers is to detect the surface temperature of the object by sensing the infrared rays emitted by the object itself in a non-contact manner. For fiber optic infrared thermometers, the difference from ordinary infrared thermometers is that infrared rays are transmitted to the sensor through optical fibers, so that the optical system and circuit system of the thermometer can be separated.
Principle of fiber optic infrared thermometer
Infrared radiation is the most widespread electromagnetic radiation that exists in nature. It is based on the fact that any object will produce its own molecules and atoms in irregular movements under normal circumstances, and constantly radiates thermal infrared energy, and the movement of molecules and atoms The more intense the radiation, the greater the energy of the radiation; conversely, the energy of the radiation is smaller. Objects with a temperature above absolute zero will radiate infrared rays due to their own molecular motion.
Therefore, by measuring the infrared energy radiated by the object itself, its surface temperature can be accurately measured. This is the objective basis on which infrared radiation temperature measurement is based. The infrared energy is focused on the photodetector and converted into a corresponding electrical signal. The signal is converted into the temperature value of the measured target after being corrected by the amplifier and signal processing circuit according to the algorithm inside the instrument and the target emissivity. Fiber optic infrared thermometer transmits light to the sensor through optical fiber instead of focusing it directly on the sensor through a lens. The rest of the principles are the same as ordinary infrared thermometers.
Advantages of fiber optic infrared thermometer
1. Since the optical system and circuit system are separated, when used in industrial field applications, the optical system of the thermometer can be installed in a high-temperature environment (withstands 200 degrees in the field environment), and can work stably online for a long time. Since the optical system does not contain electricity at all, the industrial site where it is installed is completely explosion-proof. The circuit part of the thermometer can be installed indoors or away from the high-temperature site, and connected through the optical fiber and optical path part, thus completely avoiding the high temperature at the temperature measurement site from interfering with the temperature measurement of the instrument.
2. Since the infrared signal of the fiber optic infrared thermometer is transmitted to the sensor through the infrared optical fiber of special material, when the light path is focused on the optical fiber, only the spot size of the optical fiber cross-section can be transmitted to the sensor through the optical fiber, thus avoiding The effect of focusing a large area of light directly on the sensor and baking the sensor on the working stability and life of the sensor is eliminated. In addition, the infrared optical fiber is made of special materials, and only the required infrared band can be selected to pass through the optical fiber, which further reduces the baking of the sensor by the light. Therefore, the light infrared thermometer has better stability and longer service life than the integrated infrared thermometer.
