Abstract: An induction furnace which provides a controlled escape pathway for superheated metal is disclosed. The induction furnace comprises a base layer of refractory material in the bottom of the furnace vessel. The base layer of refractory is composed of a first refractory having a maximum operational temperature and a second refractory having a maximum operational temperature lower than that of the first refractory. At least a portion of the second refractory is arranged in a contiguous zone through the thickness of the base layer. The base layer supports a packed granular refractory lining that extends up along the side wall of the vessel. In one embodiment of the invention, the base layer takes the form of a means for pushing out the packed granular lining from the furnace. The pusher means is arranged for axial movement within the furnace in response to a driving force applied from below the base layer. The pusher means contains the contiguous zone of the second refractory.

Abstract: A hot dip batch coating pot for containing a coating material in a liquid state. The pot comprises a container portion having a horizontal bottom and vertical side walls, with the bottom and said side walls defining an interior volume for containing said coating material. At least one coreless induction furnace is mounted on a side wall of the container portion. The coreless induction furnace defines an interior volume in communication with the interior volume of the container portion for inductively heating the coating material. The coreless induction furnace is disposed at an angle to the vertical.

Abstract: Apparatus for inductively melting a quantity of metal without a container includes a first induction coil having a plurality of turns defining a volume for receiving a quantity of metal, the first induction coil being adapted to exert a force on the metal, a second induction coil having a plurality of turns at substantially right angles to the turns of the first induction coil, the second induction coil, being disposed within said volume coaxial with the first induction coil. Both the first and second induction coils have connectors thereon for connecting the coils to at least one power supply for energizing the first and second induction coils. A support is provided for supporting the metal from below, and has an opening through it. The support includes a raised segmented rim around substantially its entire periphery. The support is maintained at a preselected temperature. In an alternate embodiment, structure is also provided for imparting rotational motion to the support.

Abstract: A system for simultaneously melting metal and holding molten metal for treatment and the like comprises a plurality of separate induction furnaces, each having an induction coil. The induction coil of each furnace is arranged to inductively heat metal in its associated furnace. A plural-output power supply is operatively connected to the induction coils for supplying ac power to the coils. The power supply comprises at least one rectifier section having an output and a plurality of high-frequency inverter sections equal to the number of separate induction furnaces Each inverter section has an input operatively associated with the rectifier section output for receiving power from said at least one rectifier section and an output operatively connected to a respective one of the induction coils for supplying ac power to the induction coil. Switches are provided for selectably interrupting power from selected ones of said plurality of inverter sections to their associated induction coils.

Abstract: Induction heating vessels and methods are disclosed. One embodiment of an induction heating vessel is a bottom pouring vessel with a crucible for containing a molten metal to be heated and having an outlet in the bottom. A metallic shell with integral current limiters surrounds the crucible. A stopper is provided for selectably controlling the flow of molten metal through the outlet. A method of preheating an induction heating vessel comprises placing a susceptor inside the vessel prior to charging the vessel with material to be heated and inductively heating the susceptor by an induction coil.

Abstract: An induction melting vessel comprising a refractory crucible having an opened top end and closed bottom end, with a substantially continuous side wall. A substantially continuous metallic shell surrounds and generally conforms to the side wall and extends for at least a majority of the height of the side wall from the bottom end to the top end. The shell has a bottom end corresponding to the bottom end of the crucible and a top end corresponding to the top end of the crucible. A portion the shell adjacent the top end thereof and a portion of the shell adjacent the bottom end thereof have discrete physically integral but electrically isolated regions therein for limiting the flow of electric current in the shell. In one embodiment of the invention, the regions are defined by a plurality of slits through the shell and extending from the top and bottom ends thereof toward the respective opposite ends. The slits have a length not exceeding have the distance to the respective opposite end.

Abstract: In one embodiment, an induction furnace is disclosed having a crucible, first and second set of induction coils surrounding the crucible and master and slave inverters, whereas in another embodiment, related to a channel-type induction furnace, the lower portion of the crucible houses at least first and second induction coils. The master and slave inverters each have a switching device with known turn-off-time characteristics for generating an alternating polarity output voltage across a load. The master inverter monitors the current, detects the zero-crossing of the current in the first induction coils, and generates a control signal in response to such detection of zero-crossing. The control signal is generated at an interval following the detection of the zero-crossing which is greater than the turn-off-time characteristic of the switching device.

Abstract: Method and apparatus for internally heating solid bodies using electromagnetic induction. The method comprises generating an electromagnetic induction field and causing it to induce the flow of an electric current in a preselected portion of a solid body to be heated. The electric current has a direction and magnitude sufficient to cause internal heating of the preselected portion of the body. The induction field and the body are rotated relative to one another for causing the direction of the induced current to rotate relative to the body about a preselected location to cause overheating at the preselected location. The body is cooled, except for the preselected portion to be heated. The apparatus comprises a coil for generating an electromagnetic induction field for inducing the flow of an electric current in a preselected portion of a solid body to be heated. The electric current has a direction and magnitude sufficient to cause internal heating of the preselected portion of the body.

Abstract: A vibratory flow feed conveyor with a removable conveyor pan includes a base mounted on a supporting surface, a vibrator frame fixed to the base, a conveyor pan mountable on the vibrator frame for oscillatory movement with respect thereto, connecting members on the conveyor pan and cooperating mating connector members on the vibrator frame for removably attaching the conveyor pan to the vibrator frame, and a vibrator operatively associated with the vibrator frame for imparting oscillatory movement to the vibrator frame and the conveyor pan.

Abstract: An apparatus for directing electromagnetic flux near an induction coil comprises a loop-shaped member adapted to conduct electromagnetic flux, defining an axis parallel to the central axis of the induction coil and extending substantially the length of the coil. The loop-shaped member acts as a return circuit for minimizing a stray magnetic field external to the coil.

Abstract: A control system for power delivered to an inductive load includes automatic control with a manual override for emergency situations. The system monitors the power delivered to the load and varies the power delivered to the inductive load by controlling the phase difference between the voltage and current delivered to the load. Feedback to the control system automatically controls the phase difference between voltage and current in response to the measured power delivered to the load. Provision is made for introducing an external signal into the feedback circuit, whereby the external signal supersedes the automatic control of the power delivered to the load.

Abstract: A coreless induction furnace comprising a crucible for holding a quantity of metal to be heated by the furnace. The crucible has an open top, side walls and a closed bottom. An induction coil is operatively associated with the crucible for generating a time-varying magnetic induction field. Coupling structure extending above the top of the crucible is provided to couple at least a portion of the induction field to the center portion of the top surface of the metal to be heated.

Abstract: Power is controllably supplied to a resistive load. Power is passed from a power supply through a selectably operable switch directly to the resistive load and simultaneously to an energy storage device in parallel with the load. After a predetermined interval, the energy storage means causes the switch to open, thus causing the energy stored in the energy storage means to be transferred to the load. The switch is periodically closed according to a predetermined frequency.

Abstract: The solid metal to be melted is placed within an induction coil which is adapted to provide a greater electomagnetic force towards the lower portion of the quantity of metal. The solid metal rests on a support, having an opening therethrough, which is kept at a low temperature relative to the metal as it melts. When energy is provided to the coil, the metal melts from the top downward, but the concentration of electromagnetic force towards the bottom of the metal causes the liquid metal to retain a cylindrical shape. When most of the metal is melted, the liquid metal passes through the opening in the support into a casting mold.

Abstract: An apparatus and method for inductively melting a quantity of metal, without having to contain the metal in a crucible, is described. The solid metal to be melted is placed within a first induction coil excited by an alternating current and adapted to provide a greater electromagnetic force towards the lower portion of the quantity of metal. The solid metal rests on a support, having an opening therethrough, which also comprises means for keeping the support at a low temperature relative to the metal as it melts. When energy in the form of the alternating current is provided to the coil, the metal melts from the top downward, but the concentration of electro-magnetic force towards the bottom of the metal causes the liquid metal to retain a cylindrical shape. A non-varying electromagentic field is applied to the quantity of metal to minimize violent stirring of the molten portion of the quantity of metal caused by the time-varying field.

Abstract: The instant invention is directed to a stopper rod spatial control mechanism for use in combination with a bottom discharge holding reservoir for molten metal having a nozzle. The mechanism comprises a base, an outer tube and an inner tube. The outer tube has a longitudinal axis which is perpendicular to the base. The outer tube is swingably mounted about an axis parallel to and spaced away from the longitudinal axis. The inner tube is telescopically mounted within the outer tube. The inner tube is reciprocally movable along the longitudinal axis and is rotatable about the longitudinal axis. A servomotor is mounted at a lower end of the outer tube. A ball screw is connected to and rotated by the motor. A ball nut is affixed to the inner tube and cooperates with the ball screw. A boom having a first end and a second end is affixed to the inner tube adjacent its first end and rotates with the inner tube about the longitudinal axis. A stopper rod depends from the second end of the boom.

Abstract: A method of refining steel utilizing induction melting furnaces sized for use in micro mills consists of charging a medium frequency induction melting furnace having a maximum production rate of about 50 tons per hour with pre-refined steel, and melting steel in the furnace. The melted steel is transferred to a refining vessel, the refining vessel has a high free board, induction heating and stirring capacity and apparatus for supplying blasts of gas. The refined steel is then transferred to a tundish for a continuous casting operation.

Abstract: An apparatus and method for controlling the pour of molten metal into individuals molds. The apparatus comprises a reservoir for holding molten metal to be poured into at least one mold having a sprue and a mold gating system, and a flow control device operatively associated with the reservoir for controlling the flow of molten metal from the reservoir into the mold. A sensor continuously senses the image of the surface of the molten metal in the mold and generates image area information representative of the surface area of the metal relative to the surface of the mold. A sampling circuit repetitively samples the image area information during a pour and generates sampled image area information at a preselected sampling rate. A comparator repetitively compares the sampled image area information to a preselected reference area value and generates a difference value representative of the difference between the image area information and the reference area value.

Abstract: A packaging system for an induction furnace has an equipment housing within which is located all the operating equipment for the furnace. The equipment is centrally located within the housing and is reached by access panels in the housing cover, which forms a deck. The operating equipment is fully enclosed and protected by the housing, yet can be easily reached by means of the access panels for maintenance, troubleshooting and the like.

Abstract: A plurality of carriages, each containing a pouring ladle, are provided for pouring molten metal into moving molds of a conveyor. The carriages are essentially driven from a single motor and move in a closed loop containing a loading zone and a pouring zone. Each carriage contains a clutch pump and a brake pump to control movement along the loop. Rotation of ladles to a pour position is attained by use of a parallelogram linkage on the carriage and remotely located variable pour rate controls.