Method and apparatus for pre-heating vitrifiable batch

Claim 2

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 including a plurality of spaced bars to gases from the furnace, feeding at least part of the batch onto the support, temporarily retaining batch material by such support, and heating batch material on the support until it is in at least a partly molten condition in which it flows through the spaces between bars.

Claim 3

A process as defined in claim 1 wherein during the step of retaining, batch material is temporarily retained by a plurality of supports including a plurality of spaced bars, the supports being located at different levels, and at least part of the batch material flows through at least two such supports, one after another, before reaching the furnace.

Claim 4

A process as defined in claim 1 comprising directing at least a part of the hot furnace gases to flow upwardly past and in contact with batch material on the support.

Claim 5

A process as defined in claim 3 wherein during the step of retaining, batch material is temporarily retained by a plurality of supports including a plurality of spaced bars, the supports being disposed at different levels and in staggered relationship so that, as considered in plan view, they overlap, and comprising directing at least a part of the hot furnace gases to flow upwardly along an undulating path past and in contact with batch material on each support.

Claim 6

A process as defined in claim 1 wherein during the step of heating at least part of the batch is at least partially melted while in the upper layers of a heap of batch material on the support.

Claim 7

A process as defined in claim 1 comprising directing at least part of the hot furnace gases to flow across and in contact with the top of a heap of batch material on the support.

Claim 8

A process as defined in claim 6 comprising directing at least part of the hot furnace gases to flow across and in contact with the bottom of the support and then to flow across and in contact with the top of a heap of batch material on that support.

Claim 9

A process as defined in claim 1 wherein during the step of heating the support is heated 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.

Claim 10

A process as defined in claim 1 wherein during the step of heating, an electric current is passed through batch material retained on the support thereby to generate heat in that material by Joule effect.

Claim 11

A process as defined in claim 1 comprising heating the batch to a temperature above 600° C. before feeding the batch onto the support.

Claim 12

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.

Claim 13

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.

Claim 14

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.

Claim 15

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.

Claim 16

Apparatus as defined in claim 12 wherein the support is disposed so that between such support and the inner surface of the shaft there is a gap via which said hot gases can flow upwardly past and in contact with such support.

Claim 17

Apparatus as defined in claim 12 wherein the support has a retaining wall, bordering the gap, for retaining a heap of batch material on such support.

Claim 18

Apparatus as defined in claim 12 wherein in the vicinity of the support there is a passageway for hot furnace gases which leads out of said shaft near the bottom of that support and back into said shaft at a position such that gases leaving that passageway will be directed across and in contact with batch material on such support.

Claim 19

Apparatus as defined in claim 12 comprising means for directly generating heat in the support.

Claim 20

Apparatus as defined in claim 12 wherein the support extends over the entire cross-section of said shaft.

Claim 21

Apparatus as defined in claim 12 wherein there is a plurality of supports located at different levels and in staggered relationship in said shaft so that said supports define with each other and with the inner surface of the shaft an undulating path for hot gases escaping from said furnace.

Claim 22

Apparatus as defined in claim 12 wherein the support is disposed horizontally.

Claim 23

Apparatus as defined in claim 12 wherein the support is formed by spaced bars.

Claim 24

Apparatus as defined in claim 20 wherein the support is formed by spaced hollow bars and further comprising means for circulating cooling medium through such bars.

Claim 25

Apparatus as defined in claim 12 wherein the bars have a between-bar spacing greater than 10 mm.

Claim 26

Apparatus as defined in claim 12 wherein there are at least two supports formed by spaced bars and located at different levels so that batch material can feed through one said support onto another and the supports are at different levels which have different between-bar spacings.

Claim 27

Apparatus as defined in claim 23 wherein the support has a between-bar spacing greater than that of at least one support disposed at a lower level in the shaft.

Claim 28

Apparatus as defined in claim 12 comprising means in the form of a variable-delivery vibrating distributor for feeding vitrifiable batch into said shaft.

Claim 29

Apparatus as defined in claim 12 comprising an inclined chute for guiding batch material from the bottom of said shaft into a glass-melting furnace.

Claim 30

Apparatus as defined in claim 12 wherein the support is formed by the heating means.

Claim 31

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.

Claim 32

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.

Claim 33

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.

Claim 34

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.

Claim 35

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° C. before feeding the batch onto the apertured support.

Claim 36

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° C. before feeding the batch onto the apertured support.