Method and apparatus for pre-heating vitrifiable batch

Apparatus for use in pre-heating a vitrifiable batch prior to its introduction into a glass-melting furnace, comprising a feed shaft into which vitrifiable batch can be fed and providing a flow path for hot gases escaping from such furnace, at least one support in said shaft for temporarily supporting batch material while heat is transferred to it from such hot gases, said support including a plurality of spaced bars and disposed so that its bottom side forms part of the boundary of the gas flow path and so that between such support and the inner surface of the shaft there is a gap via which such gases can flow upwardly past and in contact with such support.

Apparatus for use in pre-heating a vitrifiable batch prior to its introduction into a glass-melting furnace, comprising, a feed shaft into which vitrifiable batch can be fed, at least one support in said shaft for temporarily supporting batch material, said support having apertures, heating means for heating batch material on such support to bring such material to a flowable condition in which it can flow downwardly through the support apertures, said heating means including electrodes between which an electric current can be passed for generating heat in said supported batch material by Joule effect.

A process for pre-heating a vitrifiable batch prior to its introduction into a glass-melting furnace using hot gases from the melting furnace, comprising directly exposing at least one support having apertures to gases from the furnace, feeding at least part of the batch onto the apertured support, temporarily retaining batch material by such support, heating batch material on the support until it is in at least a partly molten condition in which it flows through the support apertures and, during the step of heating, heating the support in part by heat transferred thereto from the hot furnace gases and in part by heat generated directly in the support by another energy source.

A process for pre-heating a vitrifiable batch prior to its introduction into a glass-melting furnace using hot gases from the melting furnace, comprising directly exposing at least one support having apertures to gases from the furnace, feeding at least part of the batch onto the apertured support, temporarily retaining batch material by such support, heating batch material on the support until it is in at least a partly molten condition in which it flows through the support apertures and, during the step of heating, batch material while retained by the support is heated in part by heat transferred thereto from the hot furnace gases and in part by heat generated directly in such supported material by another energy source which includes passing an electric current through batch material retained on the support thereby to generate heat in that material by Joule effect.

A process for pre-heating a vitrifiable batch prior to its introduction into a glass-melting furnace using hot gases from the melting furnace, comprising directly exposing at least one support having apertures to gases from the furnace, feeding at least part of the batch onto the apertured support, temporarily retaining batch material by such support, heating batch material on the support until it is in at least a partly molten condition in which it flows through the support apertures, and heating the batch to a temperature above 600.degree. C. before feeding the batch onto the apertured support.