Temp. control of vertical glass panes in multichamber furnace - using optical pyrometers and thermocouples connected to microprocessor for heating panes to bending and toughening temp.

摘要

Furnace having a rapid thermal response, consists of a row of chambers through which the panes are fed stepwise and at a specific speed. The heating power in each chamber is controlled according to a pre-established programme as a function of the temp. of the chamber wall, so the panes reach a desired bending and/or toughening temp. The presence of a pane is detected at the inlet of at least one chamber, and the signal obtd. is used to control the heating power fed to subsequent chambers. The pref. furnace uses heater elements embedded in ceramic fibre panels with density ca. 200kg/cu.m.; and an optical pyrometer is pref. located in the spaces between the chambers. Accurate temp. control despite the absence of some panes creating gaps along a continuous conveyor carrying the panes through the furnace.