Infrared Radiation Techniques for Glass Surface and Temperature Distribution Measurements

The measurement of glass temperature is essential to the understanding and control of efficient glass processing operations. The physical principles of temperature measurement using infrared techniques are described. Emphasis is primarily placed on infrared radiation thermometry (pyrometry) for measuring glass surface temperature and the spectral remote sensing method for recovering temperature distribution in glass. The radiation thermometry for measuring glass surface temperature is reviewed, and difficulties caused by the presence of spectrally selective attenuation of radiation by atmospheric constituents or combustion products such as H20, C02, and others are discussed. Criteria for selecting spectral bandwidths appropriate under the circumstances of glass manufacturing are given, with special emphasis on the effects of environmental spectral absorption. A technique for reconstructing the temperature distribution in glass from remotely sensed spectral emission data is presented. The validity and accuracy of the spectral remote sensing method is established by comparing temperature profiles in glass samples under a variety of different physical conditions with independent measurements.