Furnace construction for plasma arc remelting of metal

Claim 2

A plasma arc remelting installation for producing ingots comprising: a hermetically sealable chamber; an ingot-forming mold contained in said chamber; a plurality of plasma arc torch means positioned above said mold; an electric power supply source, said torch means connectable so as to supply plasma to melt metal; and means enabling a metal charge to be arranged for melting in the plasma arcs and the moltent metal therefrom to be solidified in said mold to form an ingot, at least one of said plasma arc torch means including a plasma arc torch, a ball and socket assembly providing a sealed mounting for enabling projection of said torch from exterior to interior of said chamber so the torch nozzle is disposed within said chamber and enabling adjustment of said torch and an adjustment control mechanism mounted on said furnace adjacent to said ball and socket assembly coacting with said torch to provide and enable infinitely variable universal inclination adjustment of said torch during remelting and including at least two independently operable control members to accomplish the variable universal inclination.

Claim 3

A plasma arc remelting installation as defined in claim 1, wherein said assembly includes means enabling adjustment of said plasma arc torch for movement along its axis and for variable universal angular disposition about a selected point on its axis.

Claim 4

A plasma arc remelting installation for producing ingots comprising: a hermetically sealable chamber; an ingot-forming mold contained in said chamber; a plurality of plasma arc torch means positioned above said mold; an electric power supply source, said torch means connectable so as to supply plasma to melt metal; and means enabling a metal charge to be arranged for melting in the plasma arcs and the molten metal therefrom to be solidified in said mold to form an ingot; at least one of said plasma arc torch means including a plasma arc torch, a ball and socket assembly providing a sealed mounting for enabling projection of said torch from exterior to interior of said chamber so the torch nozzle is disposed within said chamber and enabling adjustment of said torch, and an adjustment control mechanism mounted on said furnace adjacent to said ball and socket assembly coacting with said torch to provide and enable infinitely variable inclination adjustment of said torch during remelting and including at least two independently operable control members to accomplish the variable inclination; said assembly including socket means secured to said chamber and ball means disposed for swivelling movement in said socket means; said torch having a cylindrical elongate body projecting through said ball means and sleeve gland means mounting said torch body within said ball means, said sleeve gland means sealing and permitting adjustable axial reciprocable movement of said torch relative to said ball means; said adjustment mechanism includes gimbal means operatively connected to said torch at a location exterior of said chamber; and said assembly includng further means enabling adjustment of said torch for movement along its axis as well as for the variable angular disposition about a selected point which is on the torch axis.

Claim 5

A plasma arc remelting installation for producing ingots comprising: a hermetically sealable chamber; an ingot-forming mold contained in said chamber; a plurality of plasma arc torch means positioned above said mold; an electric power supply source, said torch means connectable so as to supply plasma to melt metal; and means enabling a metal charge to be arranged for melting in the plasma arcs and the molten metal therefrom to be solidified in said mold to form an ingot; at least one of said plasma arc torch means including a plasma arc torch, a ball and socket assembly providing a sealed mounting for enabling projection of said torch from exterior to interior of said chamber so the torch nozzle is disposed within said chamber and enabling adjustment of said torch, and an adjustment control mechanism mounted on said furnace adjacent to said ball and socket assembly coacting with said torch to provide and enable infinitely variable inclination adjustment of said torch during remelting and including at least two independently operable control members to accomplish the variable inclination; said assembly including socket means secured to said chamber and ball means disposed for swivelling movement in said socket means; said torch having a cylindrical elongate body projecting through said ball means and sleeve gland means mounting said torch body within said ball means, said sleeve gland means sealing and permitting adjustable axial reciprocable movement of said torch relative to said ball means; said adjustment mechanism includes gimbal means operatively connected to said torch at a location exterior of said chamber; and said assembly includng further means enabling adjustment of said torch for movement along its axis as well as for the variable angular disposition about a selected point which is on the torch axis.

Claim 6

A plasma arc remelting installation as defined in claim 3, wherein said adjustment mechanism comprises: a mounting bracket secured to said chamber; and connection means between said gimbal means and said bracket comprising a first member mounted on said bracket for rocking movement about a first axis through the center of said ball means and a second member reciprocally mounted on said first member for movement along a second axis parallel to and offset from said first axis, said second member being connected to said gimbal means; one of said control members connected to selectively rock said first member and the other of said control members connected to selectively reciprocally shift said second member.

Claim 7

A plasma arc remelting installation as defined in claim 4, wherein the connection between one of said control members and the associated member to which it is connected includes a meshed worm and gear sector.

Claim 8

A plasma arc remelting installation as defined in claim 4, wherein the connection between one of said control members and the associated member to which it is connected includes an interengaged axially fixed rotatable screw and shiftable nut mechanism.

Claim 9

A plasma arc remelting installation as defined by claim 1, wherein a coolant system is provided for said mold and said plurality of plasma arc torch means.

Claim 10

A plasma arc remelting installation as defined by claim 1 wherein said mold forms an ingot of polygonal cross-section.

Claim 11

A plasma arc remelting installation as defined by claim 8, wherein the number of plasma arc torch means positioned above said mold is at least equal in number to the apices of the polygonal cross-section shape of said mold.

Claim 12

A plasma arc remelting installation as defined in claim 9, wherein a torch means is disposed in said chamber vertically above each apex of the polygonal cross-section shape of said mold.

Claim 13

A plasma arc remelting installation as defined in claim 9, wherein each of said plurality of torch means includes a ball and socket assembly together with associated said adjustment mechanism.

Claim 14

A plasma arc remelting installation as defined in claim 1, wherein said means enabling a metal charge to be melted provides for top feeding into said chamber of a metal charge in the shape of a blank and includes blank feeding mechanism with means for oscillational rotation of said blank about a vertial axis to accomplish symmetrical melt-off of metal from said blank during remelting.

Claim 15

A plasma arc remelting installation as defined in claim 12, said feeding mechanism adapted to selectively rotate said blank about its axis with respect to the plasma torch arcs and to move said blank along its axis into the plasma torch axes.

Claim 16

A plasma arc remelting installation as defined in claim 12, wherein said feeding mechanism comprises a connection member for attachment to said metal blank and a support means on top of said chamber with suspension means adapted for feeding said connection member axially downward, said oscillational rotation means arranged for rotating said connection member with its connected blank with respect to said plasma arc torch means.

Claim 17

A plasma arc remelting installation as defined by claim 12, wherein said feeding mechanism comprises a cable means for feeding said blank and said oscillational rotation means comprises a rotation drive for selectively rotating said blank about a vertical axis centered with respect to the plasma arcs.

Claim 18

A plasma arc remelting installation as defined by claim 15, in which said cable is wound about a drum, said drum is mounted on a vertical member which is journalled for rotation about the vertical axis of said chamber and said rotation drive comprises a hydraulic cylinder for rotating said vertical member about its axis to selectively rotate said drum cable and blank with respect to the plasma arcs.

Claim 19

A plasma arc remelting installation as defined in claim 12, wherein means are provided for ingot retraction from said mold in a downward direction during remelting.

Claim 20

A plasma arc remelting installation for producing ingots comprising: a chamber; an ingot-forming mold contained in said chamber; a plurality of plasma arc torch means positioned above said mold; an electric power supply source, said torch means connectable so as to supply plasma to melt metal; and means enabling a metal charge to be arranged for melting in the plasma arcs and the molten metal therefrom to be solidified in said mold to form an ingot; at least one of said plasma arc torch means including a plasma arc torch, a ball and socket assembly providing a sealed mounting for enabling projection of said torch from exterior to interior of said chamber so the torch nozzle is disposed within said chamber and enabling adjustment of said torch and an adjustment control mechanism mounted on said furnace adjacent to said ball and socket assembly coacting with said torch to provide and enable infinitely variable inclination adjustment of said torch during remelting and including at least two independently operable control members to accomplish the variable inclination, said torch having a center electrode and a nozzle end structure comprising an elongate hollow body coaxially surrounding and spaced from the lower end of said electrode and a plurality of circumferentially spaced apart electrically conductive heat sink inserts mounted in the interior of said body, around and radially spaced from said electrode, each said insert having a portion radially adjacent said electrode and an end of at least one of said inserts projecting axially beyond the terminal end of said electrode.

Claim 21

A plasma arc remelting installation for producing ingots comprising: a chamber; an ingot-forming mold contained in said chamber; a plurality of plasma arc torch means positioned above said mold; an electric power supply source, said torch means connectable so as to supply plasma to melt metal; and means enabling a metal charge to be arranged for melting in the plasma arcs and the molten metal therefrom to be solidified in said mold to form an ingot; at least one of said plasma arc torch means including a plasma arc torch, a ball and socket assembly providing a sealed mounting for enabling projection of said torch from exterior to interior of said chamber so the torch nozzle is disposed within said chamber and enabling adjustment of said torch and an adjustment control mechanism mounted on said furnace adjacent to said ball and socket assembly coacting with said torch to provide and enable infinitely variable inclination adjustment of said torch during remelting and including at least two independently operable control members to accomplish the variable inclination, said torch having a center electrode and a nozzle end structure comprising an elongate hollow body coaxially surrounding and spaced from the lower end of said electrode and a plurality of circumferentially spaced apart electrically conductive heat sink inserts mounted in the interior of said body, around and radially spaced from said electrode, each said insert having a portion radially adjacent said electrode and an end of at least one of said inserts projecting axially beyond the terminal end of said electrode.

Claim 22

A plasma arc remelting installation as defined in claim 18, wherein said nozzle end structure body provides an annular nozzle orifice having end means defining a nozzle orifice with a smoothly curved, convergent profile surface within said body for providing a substantially laminar flow of plasma gas past said electrode and inserts.

Claim 23

A plasma arc remelting installation as defined in claim 18, wherein at least one of said torch nozzle structure inserts has a portion axially disposed to project beyond the terminal edge of said nozzle body.

Claim 24

A plasma arc remelting installation as defined in claim 18, wherein said electrode terminal end projects beyond the terminal end of said body.

Claim 25

A plasma arc remelting installation as defined in claim 18, wherein said inserts are made from material having a heat conductivity coefficient of at least 0.3 and a melting temperature of at least 2500° C.

Claim 26

A plasma arc remelting installation as defined in claim 18, wherein said torch nozzle body includes a hollow chamber, means are provided for circulating a cooling fluid through said hollow chamber and the terminal end portion of said torch nozzle body disposed radially adjacent said electrode lower end and adjacent said inserts is solid.

Claim 27

A plasma arc remelting installation as defined in claim 18, wherein said ball and socket assembly includes means enabling adjustment of said plasma arc torch for movement along its axis and for variable angular disposition about a selected point on its axis.

Claim 28

A plasma arc remelting installation as defined in claim 24, wherein said assembly includes socket means secured to said chamber, ball means disposed for swivelling movement in said socket means, said torch having a cylindrical elongate body projecting through said ball means and sleeve gland means mounting said torch body within said ball means, said sleeve gland means sealing and permitting adjustable axial reciprocable movement of said torch relative to said ball means; and said adjustment mechanism includes gimbal means operatively connected to said torch at a location exterior of said chamber.

Claim 29

A plasma arc remelting installation as defined in claim 25, wherein said adjustment mechanism comprises: a mounting bracket secured to said chamber; and connection means between said gimbal means and said bracket comprising a first member mounted on said bracket for rocking movement about a first axis through the center of said ball means and a second member reciprocally mounted on said first member for movement along a second member being connected to said gimbal means; one of said control members connected to selectively rock said first member and the other of said control members connected to selectively reciprocally shift said second member.

Claim 30

A plasma arc remelting installation as defined by claim 18, wherein a coolant system is provided for said mold and said plurality of plasma arc torch means.

Claim 31

A plasma arc remelting installation as defined by claim 18, wherein said mold forms an ingot of polygonal cross-section.

Claim 32

A plasma arc remelting installation as defined by claim 28, wherein the number of plasma arc torch means positioned above said mold is at least equal in number to the apices of the polygonal cross-section shape.

Claim 33

A plasma arc remelting installation as defined in claim 29, wherein each torch means includes a ball and socket assembly and adjustment mechanism.

Claim 34

A plasma arc remelting installation as defined in claim 29, wherein a torch means is disposed in said chamber.

Claim 35

A plasma arc remelting installation as defined in claim 18, wherein said means enabling a metal charge to be melted provides for top feeding into said chamber of a metal charge in the shape of a blank and includes blank feeding mechanism with means for oscillational rotation of said blank about a vertical axis to accomplish symmetrical melt-off of metal from said blank during remelting.

Claim 36

A plasma arc remelting installation as defined in claim 32, said feeding mechanism adapted to selectively rotate said blank about its axis with respect to the plasma torch arcs and to move said blank along its axis into the plasma torch axes.