A sapphire fiber thermometer for high temperature measurement is described. The mechanism of the fluorescence temperature measurement is based on the basic physical phenomenon of photoluminescence. The so-called photoluminescence essentially is the superthermal radiation luminescence when some materials are stimulated by ultraviolet, visible or a certain form of the infrared electromagnetic radiation. The fluorescence lifespan and fluorescence strength of all fluorescence materials will imply some temperature correlation within some homologous temperatures. It uses a specially grown sapphire fiber as thermometer probe. The end part of the sapphire fiber is doped with Cr3+ion by means of the laser heat pedestal growth (LHPG) method and coated with some high radiant material to constitute a mini fiber cavity. The fluorescence thermal probe offers the advantages of a compact structure, a high performance and the ability to withstand high temperatures in detection. According to the surface temperature, we can obtain the inner temperature by the temperature field. It can be used to measure the steel fluid of the tundish in continuous cast steel machines. An experimental system of the thermometer and the preliminary experimental results are presented.

Date Published: 31 December 2008
PDF: 6 pages
Proc. SPIE 7130, Fourth International Symposium on Precision Mechanical Measurements, 71301A (31 December 2008); doi: 10.1117/12.819584

Published in SPIE Proceedings Vol. 7130:
Fourth International Symposium on Precision Mechanical Measurements
Yetai Fei; Kuang-Chao Fan; Rongsheng Lu, Editor(s)