Current equalization means and method for unequally loaded cables in an electric glass melting furnace

Claim 2

An electric furnace for resistive heating of a molten material having a negative temperature coefficient of resistanCe, comprising: a chamber for containing said material; a pair of electrodes immersed in said material; a source of alternating current; current carrying means comprising plural paths connected between each of said pair of electrodes and said source; and magnetic coupling means for inductive coupling of a magnetic field generated by each current path of said current carrying means in opposition to at least one other magnetic field generated by another current path of said current carrying means.

Claim 3

An electric furnace as defined in claim 1 wherein said current carrying means includes a pair of cables connected in parallel between each of said pair of electrodes and said source.

Claim 4

An electric furnace as defined in claim 2 wherein said magnetic coupling means includes a plurality of ferromagnetic cores each having an aperture through which two of said cables may be passed.

Claim 5

An electric furnace as defined in claim 3 wherein said cores extend along said cables for a distance of the order of inches.

Claim 6

An electric furnace as defined in claim 3 wherein said cores are constructed from a plurality of laminations.

Claim 7

An electric furnace as defined in claim 1 wherein said current carrying means includes first and second cables connected in parallel between one of said pair of electrodes and said current source and third and fourth cables connected in parallel between the other one of said pair of electrodes and said current source; said coupling means includes first, second and third ferromagnetic cores; and said first and third cables pass through an aperture in said first core, said second and fourth cables pass through an aperture in said second core and said first and fourth pass through an aperture in said third core.

Claim 8

An electric furnace as defined in claim 1 wherein said current carrying means includes first and second cables connected in parallel between one of said pair of electrodes and said current source and third and fourth cables connected in parallel between the other one of said pair of electrodes and said current source; said coupling means includes first and second ferromagnetic cores; said first cable and a loop of said second cable pass through an aperture in said first core such that the magnetic fields generated in said first core by current flowing in said first and second cables are in opposition; and said third cable and a loop of said fourth cable pass through an aperture in said second core such that the magnetic fields generated in said second core by current flowing in said third and fourth cables are in opposition.

Claim 9

An electric furnace for Joule effect heating of molten glass comprising: a chamber for containing said glass; a pair of electrodes immersed in said glass; a source of alternating current; N current carrying cables between said source and said pair of electrodes including, a first group of N/2 current carrying cables connected in parallel between one of said pair of electrodes and said current source, and a second group of N/2 current carrying cables connected in parallel between the other end of said pair of electrodes and said current source; and N-1 ferromagnetic cores each having one cable from said first group and one cable from said second group passing through an aperture therein whereby each of said N cables passes through an aperture in at least one of said N-1 cores.

Claim 10

An electric furnace for Joule effect heating of molten glass comprising: a chamber for containing said glass; a pair of electrodes immersed in said glass; a source of alternating current; N current carrying cables between said source and said pair of electrodes including, a first group of N/2 current carrying cables connected in parallel between one of said pair of electrodes and said current source, and a second group of N/2 current carrying cables connected in parallel between the other end of said pair of electrodes and said current source; and N-1 ferromagnetic cores each having one cable from said first group and one cable from said second group passing through an aperture therein whereby each of said N cables passes through an aperture in at least one of said N-1 cores.

Claim 11

An electric furnace for Joule effect heating of molten glass, comprising: a chamber for containing said glass; a pair of electrodes immersed in said glass; a source of alternating current; N current carrying cables between said source and said pair of electrodes including, a first group of N/2 current carrying cables connected in parallel between one of said pair of electrodes and said current source, and a second group of N/2 current carrying cables connected in parallel between the other one of said pair of electrodeS and said current source; a first group of (N/2) - ferromagnetic cores each having one cable and a loop of another cable from said first group of cables passing through an aperture therein such that the magnetic fields generated in each core of said first group of cores by current flowing in said cables are in opposition and whereby each cable of said first group of cables passes through an aperture in at least one core of said first group of cores; and a second group of (N/2) -1 ferromagnetic cores each having one cable and a loop of another cable from said second group of cables passing through an aperture therein such that the magnetic fields generated in each core of said second group of cores by current flowing in said cables are in opposition and whereby each cable of said second group of cables passes through an aperture in at least one core of said second group of cores.

Claim 12

An electric furnace for Joule effect heating of molten glass, comprising: a chamber for containing said glass; a pair of electrodes immersed in said glass; a source of alternating current; N current carrying cables between said source and said pair of electrodes including, a first group of N/2 current carrying cables connected in parallel between one of said pair of electrodes and said current source, and a second group of N/2 current carrying cables connected in parallel between the other one of said pair of electrodeS and said current source; a first group of (N/2) - ferromagnetic cores each having one cable and a loop of another cable from said first group of cables passing through an aperture therein such that the magnetic fields generated in each core of said first group of cores by current flowing in said cables are in opposition and whereby each cable of said first group of cables passes through an aperture in at least one core of said first group of cores; and a second group of (N/2) -1 ferromagnetic cores each having one cable and a loop of another cable from said second group of cables passing through an aperture therein such that the magnetic fields generated in each core of said second group of cores by current flowing in said cables are in opposition and whereby each cable of said second group of cables passes through an aperture in at least one core of said second group of cores.

Claim 13

An electric furnace for Joule effect heating of molten glass, comprising: a chamber for containing said glass; a pair of electrodes immersed in said glass; a source of alternating current; a plurality of current carrying cables connected in parallel between one of said pair of electrodes and said current source; and a ferromagnetic core having an aperture therein through which a pair of said cables pass such that the current flows in said cables are in opposition.

Claim 14

An electric furnace for Joule effect heating of molten glass, comprising: a chamber for containing said glass; a pair of electrodes immersed in said glass; a source of alternating current; a plurality of current carrying cables connected in parallel between one of said pair of electrodes and said current source; and a ferromagnetic core having an aperture therein through which a pair of said cables pass such that the current flows in said cables are in opposition.

Claim 15

An electric furnace for Joule effect heating of molten glass, comprising: a chamber for containing said glass; a pair of electrodes immersed in said glass; a source of alternating current; a first plurality of current carrying cables connected in parallel between one of said pair of electrodes and said current source; a second plurality of current carrying cables connected in parallel between the other one of said pair of electrodes and said current source; and a ferromagnetic core having an aperture therein through which a first cable from said first plurality of cables and a second cable from said second plurality of cables pass such that the current flows in said first and second cables are in opposition.

Claim 16

An electric furnace for Joule effect heating of molten glass, comprising: a chamber for containing said glass; a pair of electrodes immersed in said glass; a source of alternating current; a first plurality of current carrying cables connected in parallel between one of said pair of electrodes and said current source; a second plurality of current carrying cables connected in parallel between the other one of said pair of electrodes and said current source; and a ferromagnetic core having an aperture therein through which a first cable from said first plurality of cables and a second cable from said second plurality of cables pass such that the current flows in said first and second cables are in opposition.

Claim 17

An electric furnace as defined in claim 11 wherein the cables of said first and second plurality of cables have substantially equal electrical characteristics.

Claim 18

An electric furnace for Joule effect heating of molten glass comprising: a chamber for containing said glass; a pair of electrodes immersed in said glass; a source of alternating current; a first plurality of current carrying cables connected in parallel between one of said pair of electrodes and said current source; a second plurality of current carrying cables equal in number to said first plurality connected in parallel between the other one of said pair of electrodes and said current source; and a plurality of ferromagnetic cores each having an aperture having a pair of said cables passing through said aperture to pass their respective currents at any instant in opposite directions through said aperture, whereby each of said first plurality of cables and at least all but one of said second plurality of cables passes through an aperture in at least one core of said plurality of cores.

Claim 19

An electric furnace for Joule effect heating of molten glass comprising: a chamber for containing said glass; a pair of electrodes immersed in said glass; a source of alternating current; a first plurality of current carrying cables connected in parallel between one of said pair of electrodes and said current source; a second plurality of current carrying cables equal in number to said first plurality connected in parallel between the other one of said pair of electrodes and said current source; and a plurality of ferromagnetic cores each having an aperture having a pair of said cables passing through said aperture to pass their respective currents at any instant in opposite directions through said aperture, whereby each of said first plurality of cables and at least all but one of said second plurality of cables passes through an aperture in at least one core of said plurality of cores.