Abstract: The raw material in a raw material feeding apparatus of a melting cast installation is supplied, through a guide cylinder vertically mounted inside a furnace wall, towards a melting pot of a casting apparatus. A plurality of plasma arc torches, for heating the raw material, are positioned on the upper rotatable half of said furnace wall and are radially arranged around the axis of said guide cylinder with front ends thereof directed individually towards said melting pot. The raw material feeding apparatus may consist of a rotatable cylindrical drum laid substantially horizontally and a helical compartment wall to define a raw material path inside said cylindrical drum. A cylindrical limiter may be vertically mounted, inside said guide cylinder, for vertical movement so as to form an adjustable annular path for raw material between said limiter and the internal surface of said guide cylinder.

Abstract: In apparatus for filling a container suitable for storage with radioactive solid wastes arising from atomic power plants or the like, a plasma arc is irradiated toward a portion of the wastes to melt the portion of the wastes; portions of the wastes are successively moved so as to be subjected to irradiation of the plasma arc to continuously melt the wastes; and the melts obtained by melting the wastes are permitted to flow down toward the bottom of the container.

Abstract: A plasma torch includes an annular cathode having an annular peripheral edge from which an arc is discharged. A pair of annular nozzle elements are coaxially disposed on the opposite sides of the cathode. Each nozzle element has an annular edge hanging over the annular peripheral edge of the cathode, and the annular edges of the nozzle elements define therebetween an annular outlet opening for the torch. Gas is introduced between the cathode and the nozzle elements and emitted through the annular outlet opening in a plasma jet. A magnetic field is developed across the annular outlet opening to cause the plasma jet to rotate along the annular peripheral edge of the cathode for its uniform emission from the entire perimeter of the annular outlet opening.

Abstract: An apparatus for filling a container with radioactive solid wastes comprises a melting furnace for melting the wastes and a feed-in device for feeding the wastes into the melting furnace. The wastes introduced into the feed-in device through a charge port are fed laterally and fed from an inlet formed in the side wall of the melting furnace into the melting furnace. The wastes fed into the melting furnace are melted therein, and a resultant melt is poured from an outlet formed in the side wall of the melting furnace into a top-open container placed under the outlet.

Abstract: A device for pulverizing incombustible large solid radioactive wastes arising from atomic power plants or the like. The device comprises a furnace body provided with a vacant space for melting radioactive wastes, a gripper mounted on the furnace body to support the radioactive waste, plasma torches mounted on the furnace body to irradiate a plasma arc toward the lower end of the wastes, and a water vessel disposed below the vacant space.

Abstract: A plasma torch includes an annular cathode having an annular peripheral edge from which an arc is discharged. A pair of annular nozzle elements are coaxially disposed on the opposite sides of the cathode. Each nozzle element has an annular edge hanging over the annular peripheral edge of the cathode, and the annular edges of the nozzle elements define therebetween an annular outlet opening for the torch. Gas is introduced between the cathode and the nozzle elements and emitted through the annular outlet opening in a plasma jet. A magnetic field is developed across the annular outlet opening to cause the plasma jet to rotate along the annular peripheral edge of the cathode for its uniform emission from the entire perimeter of the annular outlet opening.

Abstract: A heat treating apparatus including a crucible to contain molten metal, at least one plasma ejecting nozzle which is constructed so as to generate a plasma jet and is secured with respect to the crucible around the central axis of it and a magnetic field generating means to generate a magnetic field interacting with the plasma jet and deflecting it.

Abstract: A feeding electrode of a heating means is a hollow cylinder with an open lower end, and is mounted on a frame. An arc-generating electrode is also mounted on the frame, and is disposed inside the feeding electrode. The lower end of the feeding electrode is immersed in a molten metal pool contained in a ladle. An electric arc struck between the arc-generating electrode and the molten metal pool inside the feeding electrode heats the molten metal pool.

Abstract: A heat treating apparatus including a crucible to contain molten metal, at least one plasma ejecting nozzle which is constructed so as to generate a plasma jet and is secured with respect to the crucible around the central axis of it and a magnetic field generating means to generate a magnetic field interacting with the plasma jet and deflecting it.