Study For Calibration Device Of Optic Fiber Radiation Thermometer For Liquid Steel

In the process of steel production,the temperature of liquid steel is an important factor to the quality of products. In order to improve the speed and accuracy of the liquid steel measurement, a new-style optic fiber radiation thermometer for liquid steel based on fiber-optic sensing technology has been designed. To ensure the measuring accuracy of the measurement results in the process of production, a radiation source is needed to calibrate the optic fiber radiation thermometers. At present, most of the industrial radiation thermometers are calibrated by the blackbody furnace. However, due to the restriction of high-temperature materials, producing a high-temperature blackbody furnace is a big expense and the heating-up time required to the setting calibration temperature-point is too long. Therefore, it couldn't meet the requirement for rapid and batched calibration.In this paper, considering the limitations in calibrating the fiber optical radiation pyrometers with blackbody furnace, according to the principle of radiation thermometry, a new calibration device using tungsten strip lamp as the radiation source is introduced.First, the principle of radiation thermometry is discussed in details and the verification system of radiation thermometer is introduced. According to the theory of blackbody radiation, the working principle and mathematical model of the calibration device is deduced. Meanwhile, the characteristics of tungsten strip lamp and the design proposal of the calibration device are introduced in details. In the end, based on the calibration experiments, accuracy and uncertainty of the calibration device is evaluated and the expended uncertainty in 1500℃is 4.2℃.After testing for nearly one year, the error of calibration is no more than 3℃. It has come up to the calibration requirements of optical fiber radiation thermometer for liquid steel. The device is inexpensive and easy to operate with simple structure. It could calibrate the optical fiber radiation thermometers in a shorter time and meet the requirements for on-spot calibration and batched production. As a result, it will improve the economic benefits and has a great potential market value.