Electronic boosting control for a glass forehearth

摘要

Appts. for heating molten glass flowing through the conditioning section of a forehearth comprises (a) several pairs of electrodes extending through the sidewalls of the forehearth with their ends terminating adjacent the sidewalls; (b) a circuit connected to the electrodes to provide Joule effect heating of the glass adjacent to the hearth sidewalls, and a source of current and a current controller; (c) two temperature sensors, one positioned in the forehearth at its centre line, adjacent to the end of the conditioning centre, including a thermocouple immersed in the glass; one extending into the forehearth adjacent its sidewall in alignment with the first sensor; (d) a settable override circuit connected to the circuit supply appts. and appts. connecting the override circuit with the second temp. sensor for adjusting the current to the electrodes so as to provide a selected sidewall temp. A system is provided in which a set current level selected by operator can be applied to electrodes positioned in the conditioning section of the furnace so that the sidewall temp. can be brought into agreement with the centre line temp. providing optimum conditioning.