Furnaces for heating glass

Claim 2

A furnace comprising: a. a furnace chamber for containing glass in the molten state having a bottom wall and an upstanding peripheral wall, b. upstanding rod-like electrodes arranged within the chamber in respective rows defining the lateral boundaries of a plurality of adjacent heating zones, each having a length exceeding its lateral dimension, and collectively occupying substantially the whole of the furnace chamber, c. an alternating current supply circuit having i. input terminals for connection respectively to the poles of a polyphase source of alternating current, ii. output terminals each connected to one or more of said rows of electrodes iii. transformer means iv. conductor means connecting said transformer means in a configuration between said input and output terminals to apply a voltage across each of said heating zones, and v. regulator means for adjusting said voltages relatively to each other.

Claim 3

A furnace according to claim 1 wherein: a. the number of heating zones is equal to the number of phases of the polyphase source multiplied by a whole number b. the transformer means includes a number of primary windings and a number of secondary windings each equal in number to the number of phases of the source, c. said secondary windings are connected to said output terminals and therethrough to the rows of electrodes in such a manner that each secondary winding applies voltage across the same number of heating zones as do the remaining secondary windings.

Claim 4

A furnace according to claim 1 wherein: a. the input terminals are connected to a three-phase alternating current source, b. the transformer means includes primary and secondary windings connected by said conductor means for effecting conversion from said three-phase source to develop two-phase output voltages at said output terminals, c. the total number of said heating zones is an even number, d. said output terminals are connected to said rows of electrodes in a manner such that each of said two phase voltages is applied across an equal number of said heating zones.

Claim 5

A furnace according to claim 1 wherein: a. the input terminals are connected to a three-phase source, b. the transformer means includes primary and secondary windings for effecting conversion from said three-phase source to develop two-phase output voltages in quadrature with each other at said output terminals, one of said output terminals being common with respect to said output voltages and two non-common with respect to said output voltages, c. the total number of the heating zones is an odd number, d. said output terminals are connected to said rows of electrodes in such a manner that each of said output voltages is applied across an equal number of said heating zones, and an additional one of said heating zones is bounded laterally by rows of electrodes connected respectively to said non-common output terminals.

Claim 6

A furnace according to claim 1 wherein: a. said input terminals are connected to a three-phase alternating current source, b. the transformer means comprises separate transformers each including a respective secondary winding and a respective primary winding, c. said respective secondary windings are connected in series with each other to provide a common one of said output terminals and two non-common ones of said Output terminals, d. said respective primary windings are connected by said conductor means in circuit with a further transformer to said input terminals.

Claim 7

A furnace comprising: a. a furnace chamber for containing glass in the molten state having a bottom wall and an upstanding peripheral wall, b. upstanding rod-like electrodes arranged within the chamber in respective rows defining the lateral boundaries of a plurality of adjacent heating zones, c. an alternating current supply circuit having i. input terminals for connection respectively to the poles of a polyphase source of alternating current, ii. output terminals each connected to one or more of said rows of electrodes iii. transformer means, iv. conductor means connecting said transformer means in a configuration between said input and output terminals to apply a voltage across each of said heating zones, and v. regulator means for adjusting said voltages relatively to each other. d. at least one outlet in said furnace chamber for outflow of glass therefrom, e. channel means in a lower part of said furnace chamber including channels extending from each of said zones to said outlet whereby stagnation or inequality of dwell or residence time of glass in any of said heating zones relatively to the remainder is reduced.

Claim 8

A furnace comprising: a. a furnace chamber for containing glass in the molten state having a bottom wall and an upstanding peripheral wall, b. upstanding rod-like electrodes arranged within the chamber in respective rows defining the lateral boundaries of a plurality of adjacent heating zones, c. an alternating current supply circuit having i. input terminals for connection respectively to the poles of a polyphase source of alternating current, ii. output terminals each connected to one or more of said rows of electrodes iii. transformer means, iv. conductor means connecting said transformer means in a configuration between said input and output terminals to apply a voltage across each of said heating zones, and v. regulator means for adjusting said voltages relatively to each other. d. at least one outlet in said furnace chamber for outflow of glass therefrom, e. channel means in a lower part of said furnace chamber including channels extending from each of said zones to said outlet whereby stagnation or inequality of dwell or residence time of glass in any of said heating zones relatively to the remainder is reduced.

Claim 9

A furnace according to claim 6 wherein: a. said channel means includes: i. a collector channel leading from a central region of said bottom wall to said outlet, ii. feeder channels extending transversely of said collector channel to convey glass thereto from heating zones spaced laterally from said collector channel.

Claim 10

A furnace according to claim 7 wherein said channel means includes further feeder channels extending longitudinally of respective heating zones and communicating with the first said feeder channel.

Claim 11

A furnace according to claim 6 wherein said channel means is defined by raised parts of said bottom wall of said furnace, through which raised parts said electrodes extend.

Claim 12

A furnace according to claim 9 wherein: a. said raised parts, through which said electrodes extend in at least those rows other than the rows situated at lateral boundaries of said furnace chamber, are separated from each other by gaps or slots defining the first said feeder channels.

Claim 13

A furnace according to claim 9 wherein said raised parts comprise block elements which are structurally separate from the remainder of said bottom wall of said furnace chamber and are made of a material which is selected to have a resistance to erosion under operating conditions of the furnace which is greater than that provided by those parts of said bottom wall relatively to which said block elements are raised.

Claim 14

A furnace according to claim 7 wherein said collector channel is situated beneath a portion of the glass in said furnace chamber which is at or near earth potential.

Claim 15

In a furnace comprising an elongate furnace chamber for containing glass in the molten state having a bottom wall and upstanding side and end walls extending respectively along the longer and shorter peripheral boundaries of the bottom wall through which latter respective rod-like electrodes extend, the improvement wherein: a. the rod-like electrodes are arranged within the chamber in respective rows each extending generally parallel to said end walls and each containing more than two of said electrodes, said rows defining lateral boundaries of a plurality of laterally adjacent heating zones having lateral dimensions less than their lengths between said side walls of said chamber, b. said heating zones collectively occupy substantially the whole of said furnace chamber, c. said furnace chamber has at least one outlet adjacent a respective one of said side walls, d. said bottom wall includes means defining channels extending from said heating zones to said outlet, e. an alternating current supply circuit is connected to said eleCtrodes to provide respective voltages across said heating zones.

Claim 16

In a furnace comprising an elongate furnace chamber for containing glass in the molten state having a bottom wall and upstanding side and end walls extending respectively along the longer and shorter peripheral boundaries of the bottom wall through which latter respective rod-like electrodes extend, the improvement wherein: a. the rod-like electrodes are arranged within the chamber in respective rows each extending generally parallel to said end walls and each containing more than two of said electrodes, said rows defining lateral boundaries of a plurality of laterally adjacent heating zones having lateral dimensions less than their lengths between said side walls of said chamber, b. said heating zones collectively occupy substantially the whole of said furnace chamber, c. said furnace chamber has at least one outlet adjacent a respective one of said side walls, d. said bottom wall includes means defining channels extending from said heating zones to said outlet, e. an alternating current supply circuit is connected to said eleCtrodes to provide respective voltages across said heating zones.

Claim 17

The improvement claimed in claim 13 wherein said loading of said polyphase source is at least approximately balanced.

Claim 18

A furnace according to claim 1 wherein: a. each of said rows of electrodes includes more that two electrodes, b. in each of said rows successive electrodes are spaced apart by a distance less than the least lateral dimension of the heating zone or zones bounded laterally by said row.

Claim 19

A furnace according to claim 6 wherein: a. said channel means includes a plurality of collector channels each extending longitudinally of a respective one of said heating zones, b. said furnace chamber has outlets communicating respectively with said collector channels.

Claim 20

A furnace according to claim 6 wherein: a. said channel means includes a plurality of collector channels each extending longitudinally of a respective one of said heating zones, b. said furnace chamber has a single outlet communicating with each of said collector channels.

Claim 21

A furnace according to claim 13 wherein the channels include: a. a channel extending longitudinally within each of said heating zones, b. channels extending laterally of said heating zones connecting each of said longitudinally extending channels with laterally adjacent ones thereof.

Claim 22

A furnace according to claim 18 wherein: a. said laterally extending channels extend between adjacent electrodes in said rows, b. said adjacent electrodes extend upwardly through respective raised portions of said bottom wall having upwardly presented surfaces above the bottoms of said channels.

Claim 23

A furnace according to claim 19 wherein said electrodes in rows situated adjacent to said end walls extend upwardly through raised portions of said bottom wall contiguous with said end walls and extending continuously therealong between said side walls.

Claim 24

A furnace according to claim 18 wherein the furnace chamber has a single outlet at a position on the mid-region of the length of one of said side walls.

Claim 25

A furnace according to claim 13 wherein: a. the channels include channels extending longitudinally within each heating zone, b. an outlet is provided in said chamber at an end of each of said zones.

Claim 26

A furnace comprising: a. a furnace chamber for containing glass in a molten state having a bottom wall and an upstanding peripheral wall, b. upstanding rod-like electrodes arranged within the chamber in respective rows defining the lateral boundaries of a plurality of adjacent heating zones and collectively occupying substantially the whole of the furnace chamber, each of said rows comprising at least three electrodes spaced apart from each other longitudinally of the row by a distance less than the minimum lateral dimension of a heating zone of which said row defines a lateral boundary, c. an alternating supply circuit having i. input terminals for connection respectively to the poles of a polyphase source of alternating current, ii. output terminals each connected to one or more of said rows of electrodes, iii. transformer means, iv. conductor means connecting said transformer means in a configuration between said input and output terminals to apply a voltage across each of said heating zones, and v. regulator means for adjusting said voltages relatively to each other.

Claim 27

A furnace comprising: a. a furnace chamber for containing glass in a molten state having a bottom wall and an upstanding peripheral wall, b. upstanding rod-like electrodes arranged within the chamber in respective rows defining the lateral boundaries of a plurality of adjacent heating zones and collectively occupying substantially the whole of the furnace chamber, each of said rows comprising at least three electrodes spaced apart from each other longitudinally of the row by a distance less than the minimum lateral dimension of a heating zone of which said row defines a lateral boundary, c. an alternating supply circuit having i. input terminals for connection respectively to the poles of a polyphase source of alternating current, ii. output terminals each connected to one or more of said rows of electrodes, iii. transformer means, iv. conductor means connecting said transformer means in a configuration between said input and output terminals to apply a voltage across each of said heating zones, and v. regulator means for adjusting said voltages relatively to each other.