The characteristics of four types of radiation pyrometers in which Si cell, Phototube (Sl), thermopile, and PbS cell are used respectively, have been studied. Influences of emissivity variation, water film, steam, and scale on pyrometer readings are measured. A rotary furnace is used as a model that treats moving hot steel sheets.
As the standard of radiation pyrometers, a blackbody furnace and its effective emissivity has been investigated.
Results obtained are as follows.
1) The effects of emissivity variation, water film, steam, and scale on are smaller for the radiation pyrometers using shorter wave lengths (<lu) than for those using longer wave lengths.
2) The temperature distributions of the spherical blackbody furnace are excellent at present momen and the estimated effective emissivity is expected to be greater than 0.995.
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