Abstract: A preheater for cullet is disclosed, in which hot gas coming from a hot supply duct can be passed through the cullet while yielding heat to the latter and can be carried away through a hot gas exhaust duct. The cullet is guided between guiding walls forming a cullet shaft and permitting gas entry as well as gas exit. Means are provided for repeatedly moving at least one of the guiding walls (23, 24,25,26) laterally relative to another guiding wall (23-26) so as to change the spacing between them.

Abstract: A method and a system for uniformly heating a glass stream flowing in the feeder of a glass melting furnace wherein power or energy is supplied through the electrodes immersed in the glass melt and wherein the temperature of the glass stream is continuously detected, has the current flowing between cooperating electrodes maintained constant independently of the resistance defined by the glass melt by controlling the voltage as long as the temperature of the glass stream does not deviate from predetermined limits and the current flow of at least a number of electrodes positioned at the inlet of the feeder are controlled to compensate for temperature variations when the tolerable deviation limit has been exceeded.