Abstract: An electric arc furnace includes a crucible having a metal shell for recovering precious metals from spent material. The shell includes a metal tap hole and a slag door positioned above and opposite the metal tap hole. A removable swinging roof is provided above the crucible together with a plurality of electrodes for heating the spent material. Also, a cooling band circumscribes the crucible for cooling the metal shell. Conveyors are provided for distributing the spent material at a plurality of points located between the electrodes and the wall of the crucible. The crucible is tilted to allow the removal of the slag and metal.

Abstract: A combination left- and right-handed roof system adapted for use in electric arc or other furnaces having roof removal in either a clockwise or counterclockwise direction. The roof system is spray cooled by a coolant and includes a coolant drain system divided into at least two segments and having opposing inlets for receiving spent coolant. Two pairs of adjacent coolant outlets are provided for connection with a coolant collection pump, depending upon the direction of roof removal, and each outlet in each of the pairs is associated with a different drain system segment. A removable U-shaped conduit connects the two outlets of the pair disconnected from the coolant collection pump. Coolant may flow from one inlet, directly through a single drain system segment, and be removed from the roof through one of the connected outlets. Coolant may independently flow from the opposite inlet, through the U-shaped conduit and another drain segment, and be removed from the roof through the other connected outlet.

Abstract: A vessel for handling a heated substance such as molten materials, and a method for cooling such a vessel, the vessel having fluid cooled containment means comprising inner and outer walls defining a space therebetween; an inlet into the space for a pressurized fluid coolant; means for spraying the coolant against the inner wall to maintain a desired temperature at the inner wall; an outlet for removing the spent coolant; and means for establishing and maintaining a pressure differential between the space and the coolant outlet to force the spent coolant out of the space through the outlet. The preferred embodiment of the invention is utilized as a roof or side wall for a metallurgical vessel, for example, an electric arc furnace.

Abstract: A spray cooling system for cooling a furnace for the melting or treatment of molten metal, and particularly the roof and/or sidewall of electric-arc, plasma-arc and ladle furnaces. Other types of metal treating furnaces and accessory equipment may also be cooled with the system of the invention. In the invention, spray headers and pipes (14, 16, 18) supply coolant to spray nozzles (70) distributed within a coolant space in a roof structure (10) to spray coolant against the working plates (22) of the roof. The spray pipes and headers also comprise part of the framework for the roof, resulting in a simple, lightweight, one-piece structure. A pump (56) is connected to evacuate the coolant from the coolant space, and thermocouples (58) are embedded in the working plates to monitor their temperature and operate controls to adjust the flow rate so that only the amount of coolant necessary to maintain a desired temperature is supplied to the roof.

Abstract: An electric steel-making furnace with improved spray cooling features. Used spray coolant is disposed of, preferably after gravity removal from the furnace, by means of disc-type pumps, which can be operated continuously, even with a variable or discontinuous supply of exhaust coolant, at great savings compared to venturi-type pumps. Improved discharge outlet arrangements are provided to accommodate forward and rearward tilting movements of the furnace, as in the pouring off of slag and in the tapping of the molten steel product. These provisions may include a novel form of quick-disconnect fitting, to accommodate swinging away of the furnace roof for charging. Simple and efficient delta cooling means are also provided.

Abstract: A spray cooling system for cooling a furnace for the melting or treatment of molten metal, and particularly the roof and/or sidewall of electric-arc, plasma-arc and ladle furnaces. Other types of metal treating furnaces and accessory equipment may also be cooled with the system of the invention. In the invention, spray headers and pipes (14, 16, 18) supply coolant to spray nozzles (70) distributed within a coolant space in a roof structure (10) to spray coolant against the working plates (22) of the roof. The spray pipes and headers also comprise part of the framework for the roof, resulting in a simple, lightweight, one-piece structure. A pump (56) is connected to evacuate the coolant from the coolant space, and thermocouples (58) are embedded in the working plates to monitor their temperature and operate controls to adjust the flow rate so that only the amount of coolant necessary to maintain a desired temperature is supplied to the roof.

Abstract: A roof assembly for an electric arc furnace having a plurality of water cooled trapezoidal-shaped roof segments or panel units arranged in a circular manner and having arcuate surfaces which abut inner and outer fabricated welded support rings and having longitudinal surfaces which do not contact the adjacent panels when in an assembled form. The arcuate surface abutting the inner ring is slanted downwardly towards the outer ring from the top to the bottom surface of the panel, and that abutting the outer ring may have point contact creating a wedging effect for each panel between the support rings. The outer ring provides several spaced apart load bearing members defining openings which permit debris to slide off the assembled roof thereby limiting build-up on the roof, and a conduit of the support rings carries coolant to protect the weldment areas of the rings.

Abstract: A fluid cooled roof assembly for an electric arc furnace comprised of at least three circular sector shaped panels having coolant passages and an outer ring member supporting a plurality of connected arcuate ring sectors which extend upwardly away from the interior of the furnace giving added height thereto, and on which the assembled panels are supported in a flat disposition. The circular sector panels, when assembled, are designed to provide ports for receiving the electrodes and come together at a point location in the center of the roof forming a full circle which completely covers the furnace.

Abstract: A water cooled roof for an electric arc furnace made up of a multiplicity of water cooled panels surrounded by a water distribution and collection ring, each portion of the roof being insulated from each other portion, including the roof panel, support arms and the roof rack. The invention provides a means for interrupting the flow of an inductive current around each electrode by creating a gap in the metal surrounding each electrode, thus insulating the furnace roof or cover from each phase of the three phase current.

Abstract: A roof assembly for an electric arc furnace having a plurality of water cooled trapezoidal-shaped roof segments or panel units arranged in a circular manner and having arcuate surfaces which abut inner and outer fabricated welded support rings and having longitudinal surfaces which do not contact the adjacent panels when in an assembled form. The arcuate surface abutting the inner ring is slanted downwardly towards the outer ring from the top to the bottom surface of the panel, and that abutting the outer ring may have point contact creating a wedging effect for each panel between the support rings. The outer ring provides several spaced apart load bearing members defining openings which permit debris to slide off the assembled roof thereby limiting build-up on the roof, and a conduit of the support rings carries coolant to protect the weldment areas of the rings.

Abstract: Electric furnace dome that is made especially of ceramic material and which has the necessary openings for at least electrodes and material feed, at which time the dome's center (2) inside of the tube systems (3) is cooled at least around the openings with the aid of spiral tube systems (5,7,8,9) whose tube systems (3,5,7,8,9) form a part of the dome's support system.

Abstract: Wall and roof sections for electric arc furnaces are made of graphite blocks with removably attached fluid cooled panels.

Abstract: A cover for a metallurgical vessel has a top part formed as a flat, generally circular, and normally horizontal array of tubes having an outer edge and forming a plurality of vertically throughgoing passages. These tubes extend mainly angularly of the center of the array. Respective pluralities of annular tubes at and extending around the passages are connected with each other at the center and with the tubes of the flat array. This top part has a skirt formed as an annular array of generally vertical tubes extending downwardly from the outer edge and connected with the tubes of the flat array. Respective partially circularly annular collars at the passages on the flat array have inwardly directed closely juxtaposed ends. The collars and tubes are connected together as a rigid assembly. A coolant is circulated through the tubes.

Abstract: A liquid cooled cover for an electric furnace, wherein in order to lengthen the service life of the thermally highly stressed cover, cooling pipes are located essentially parallel and approximately vertically to the furnace tipping direction at a predetermined distance from each other. The cooling pipes are embedded in a fireproof construction material (57, 57') and constitute its reinforcement. The cooling liquid is supplied and removed exclusively via a cover ring, which is constructed as a cooling liquid distributing conduit in the periphery of the cover and which provided with integrated bypass openings. The composite construction of cooling pipes and fireproof construction material achieves a high thermal and mechanical stability of the furnace cover and the cooling system is largely removed from altering temperature stresses.

Abstract: A cover for a metallurgical vessel comprises an annular outer tubular collar defining a center, a plurality of tubular legs extending inwardly from the collar toward the center, and an annular inner tubular collar fixed to the legs and defining a plurality of throughgoing passages. The inner collar is formed by respective inwardly concave tubular sections defining the passages and respective inwardly convex and tubular elbow sections carried on the legs between the passages and forming an undulating annulus with the inwardly concave sections. A multiplicity of cooling tubes extend between the collars and legs and are connected thereto, and a cooler is provided for circulating a coolant through the tubes, collars, and legs. This system ensures excellent cooling right at the passages, so electrodes extending through these passages need not be provided with their own coolers.

Abstract: The invention relates to heat exchange devices for cooling the wall and the refractory of a blast-furnace. Such a device comprises a body shaped substantially as a body of revolution and having first and second end walls and a curved wall extending therebetween, the first end wall being a heat-transfer wall, a supply port and a discharge port for heat-transfer fluid, the ports being spaced-apart radially, the supply port being adapted for tangentially supplying the heat-transfer fluid into the body and the discharge port being adapted for tangentially discharging the heat-transfer fluid from the body, so that, in use, the fluid flows between the ports in a spiral path over the inner surface of the first end wall, the body having no internal obstacle to such flow. (FIG.

Abstract: A dome for an electric arc furnace comprising a central portion of refractory material and a cooled metallic crown consisting of two toroidal conduits joined by radial tubes in such a manner that it is curved. Its own volume permits variations in gas emissions during steel production to be absorbed. It comprises a manifold which fits into an extraction pipeline, so that most of the gas may be collected so as to avoid pollution. A fluid circulates in the conduits and the tubes to cool the crown.

Abstract: The invention relates to a cover for a vessel for a metal melting furnace, in particular an electric arc furnace, with cooling-pipe coils connected to the cover frame and distributed across it, at least one of which cooling-pipe coils is exposed to the furnace hearth, all of which coils lie adjacent to each other.