Light guide for transmitting heat radiation from a molten metal to a pyrometer and a method of measuring the temperature of molten metal in a metallurgical vessel using a light guide

摘要

The invention relates to a method and an arrangement intended for measuring the temperature of molten metal 5 in a vessel 4 provided with a lining 6. A light guide 1 of a transparent, heat resistant and corrosion resistant material is passed through the lining 6 and consists of a narrow part in the form of a rod and a broad part 3 with a flat end, where the wide part 3 acts as an optical cavity, radiating essentially as a black body with the temperature of the molten metal, which transmits radiation to a pyrometer 7 via the narrow part. The quotient between the cross-sectional area of the narrow part and the lateral surface area of the wide part 3 facing the molten metal does not exceed 0.5. According to the method, this light guide 1 is mounted in a zone in the vessel 4 where the molten metal 5 has maximal circulation caused by convection and at a depth h that is not less that the sum of the thickness t of the lining 6 and a value that is equal to half the maximal transverse dimension d of the wide part 3 of the light guide. IMAGE