Abstract: Disclosed herein are a graphite crucible for electromagnetic induction-based silicon melting and an apparatus for silicon melting/refining using the same, which performs a melting operation by a combination of indirect melting and direct melting. The crucible is formed of a graphite material and includes a cylindrical body having an open upper part through which a silicon raw material is charged into the crucible, and an outer wall surrounded by an induction coil, wherein a plurality of slits are vertically formed through the outer wall and an inner wall of the crucible such that an electromagnetic force created by an electric current flowing in the induction coil acts toward an inner center of the crucible to prevent a silicon melt from contacting the inner wall of the crucible.

Abstract: Various embodiments provide an apparatus and methods for containing the molten materials within a melt zone during melting. The apparatus may include a vessel configured to receive a material for melting therein and an induction coil with unevenly spaced turns along its length. Induction coil can have a series of turns acting as a first (e.g., load) induction coil and a series of turns acting as a second (e.g., containment) induction coil. The material in the vessel can be heated and contained by the separated turns of the induction coil. A plunger can also assist in containing material during melting. Once the desired temperature is achieved and maintained for the molten material, operation of the induction coil can be stopped and the molten material can be ejected from the vessel into a mold using the plunger.

Abstract: Apparatus and process for heating and melting a material in a susceptor vessel are provided wherein phase synchronized ac voltage is supplied from a separate power source to each one of at least two induction coils in separate zones around the vessel. Power magnitude from each source to an induction coil is controlled by pulse width control of the source's output voltage. Output frequency from each source is either fixed or variable based upon the electrically conductive state of the material. Optional electromagnetic stirring is achieved by establishing a phase shift between the voltage outputs of the power supplies after the material in the susceptor vessel has melted.

Abstract: An induction furnace includes a melting induction coil for inductively heating a pair of susceptors for melting particulate material falling freely in a free fall zone between the susceptors. A feeder having a rotatable hollow shaft with fingers extending therefrom breaks up the material, which falls onto a vibrating dispersion plate and then into the free fall zone. A preheating induction coil inductively heats a susceptor which radiates heat to particulate material moving over the dispersion plate. An adjustable gap between the feeder and dispersion plate controls material flow. A funnel collects falling molten material and directs it through a nozzle into a mold. Induction coils control melting within the funnel. One induction coil heats the nozzle and may be controlled to allow the nozzle to cool sufficiently to form a solid plug in the nozzle whereby molten material pools above the plug.

Abstract: A pusher furnace includes furnace sections having respective susceptors, a slide rail extending through the furnace sections for sliding pusher plates thereon and an alignment assembly for aligning the susceptors and slide rails of adjacent furnace sections. A support structure spaces the susceptors from insulation therebelow to protect the insulation from degradation from contact with the susceptors. The susceptors are slidably mounted on the support structure to accommodate thermal expansion and shrinkage of the susceptor. The upstream end of the slide rails have beveled upper edges to help prevent the pusher plates from catching thereon. The upstream ends are also laterally tapered to reduce the degree of force encountered should a pusher plate catch thereon. Adjacent insulation members have expansion joints filled with a refractory felt. The susceptors slidably and sealingly engage exhaust ports to allow for thermal expansion and shrinkage of the susceptor without damaging the exhaust port.

Abstract: A compression system for an inductively heated pusher furnace controls movement of susceptors during thermal contraction thereof. The system includes a plurality of furnace sections each having a susceptor wherein each susceptor abuts an adjacent susceptor and wherein the susceptors include first and last susceptors. A compression plate abuts the first susceptor to apply force thereon toward the last susceptor to keep the susceptors in abutment with each other during contraction of the susceptors during cooling thereof. An actuator for moving the compression plate is preferably automatically controlled by a computerized control system. The susceptors together form a tunnel through which pusher plates travel and have overlapping joints which seal against the escape of gasses and allow for a degree of susceptor contraction without forming a gap therebetween even in the absence of compression of the susceptors.

Abstract: An induction furnace includes a pair of induction coils with a pair of faraday rings disposed between the induction coils to substantially prevent mutual inductance between the first and second induction coils. The induction coils preferably have a different size circumference and may be coplanar. The prevention of mutual inductance provided by the faraday rings is particularly useful for a pusher furnace in which adjacent furnace sections are heated to different and rather specific temperatures.

Abstract: An induction furnace includes an induction coil, an electrically non-conductive crucible having an inner diameter disposed within the induction coil, and an electrically conductive member disposed below the crucible and having an outer diameter which is further from the induction coil than is the inner diameter of the crucible. Due to the non-conductive nature of material disposed within the crucible at lower temperatures, the induction coil initially inductively heats the conductive member, which transfers heat to the material to melt a portion of the material. Once the material is susceptible to inductive heating (usually upon melting) the susceptible material is inductively heated by the induction coil. During the process, inductive heating of the material greatly increases as inductive heating of the conductive member greatly decreases due to low resistivity of the molten material and due to the molten material being closer to the coil than is the conductive member.

Abstract: An induction furnace includes an induction coil, an electrically non-conductive crucible having an inner diameter disposed within the induction coil, and an electrically conductive member disposed below the crucible and having an outer diameter which is further from the induction coil than is the inner diameter of the crucible. Due to the non-conductive nature of material disposed within the crucible at lower temperatures, the induction coil initially inductively heats the conductive member, which transfers heat to the material to melt a portion of the material. Once the material is susceptible to inductive heating (usually upon melting) the susceptible material is inductively heated by the induction coil. During the process, inductive heating of the material greatly increases as inductive heating of the conductive member greatly decreases due to low resistivity of the molten material and due to the molten material being closer to the coil than is the conductive member.

Abstract: This invention relates to a device for melting or refining glass or glass ceramics. According to the invention, such a device is provided with the following characteristics: a channel which is arranged in an essentially horizontal manner and which is provided with an inlet and an outlet for the glass melt; and an HF coil for coupling HF energy into the melt is allocated to the channel. The channel is made of a plurality of metal pipes in a similar way to a skull pot. Said pipes can be connected to a cooling medium.

Abstract: The invention relates to a device for melting or refining glass or glass ceramics. According to the invention, a device of this type is provided with the following characteristics: a plurality of tubes which are U-shaped and arrange side by side so that they form a cage like skull channel that is open on top, and a high frequency oscillation circuit which comprises an induction coil. The tubes can be connected to a cooling medium. The induction coil wraps around the channel in such a manner that winding sections extend along the lateral walls of the channel.

Abstract: The invention relates to a device for melting or refining glass or glass ceramics. According to the invention, a device of this type is provided with the following characteristics: a plurality of tubes which are U-shaped and arrange side by side so that they form a cage like skull channel that is open on top, and a high frequency oscillation circuit which comprises an induction coil. The tubes can be connected to a cooling medium. The induction coil wraps around the channel in such a manner that winding sections extend along the lateral walls of the channel.

Abstract: The invention relates to a device for the melting or purifying of inorganic substances, in particular of glass, which comprises a number of metal tubes which may be attached to a cooling medium and which are arranged next to each other, in such a way that together they form a container, a high frequency coil for the injection of energy into the container contents and a plastic coating for the metal tubes, the decomposition temperature of which lies below the temperature of the melt. The cooling system is configured and arranged, such that the temperature of the boundary layer of the melt, immediately surrounding the component, lies beneath that of the decomposition temperature of the coating material.

Abstract: A metallothermy method includes continuously withdrawing an ingot of a metal product such as uranium or a uranium alloy as it is formed from an oxide or salt of the metal. The method employs upper and lower communicating crucibles. The upper crucible contains a layer of reducing medium floating on a solvent medium. The metal oxide or metal salt is reduced as it is introduced into the layer reducing medium to form metal particles and slag. The settling metal is melted by further induction heating, collected in the lower crucible and withdrawn. The slag is absorbed by the solvent medium which is regenerated with the use of electrolysis.

Abstract: There is described a hybrid furnace comprising a microwave source, and an enclosure for the confinement of both microwave and RF energy for containing an object to be heated. The microwave source is coupled to the enclosure. The furnace further includes an RF source coupled to the enclosure, and a controller for controlling the quantity of microwave energy and RF energy to which the object to be heated is exposed. There is also described a method of operating a furnace of the above type to the heat an object. The microwave source is actuated to induce an electric field to heat the object and the RF source is controlled to selectively provide an oscillating electric field within the object to be heated at a location at a temperature where the field strength of the microwave-induced electric field falls below a predetermined threshold value.

Abstract: A metal material such as scraps of metal is directly heated by electromagnetic induction, and the resulting molten metal is fed to a heatup zone where the molten metal is further heated to a required temperature. More specifically, the metal material to be melted, which has been charged into a heat and melt zone, is preheated and melted by an induction coil, and the molten metal is passed via a connection portion to the heatup zone, and is stored there. The thus accumulated molten metal is further heated by an induction coil to a necessary temperature. The molten metal is taken out of the furnace by opening a tap hole when this is desired. Various kinds of gases can be selectively introduced into the apparatus via an gas inlet. By keeping the tap hole in an open condition, the molten metal can be continuously taken out of the furnace. With the induction heating method which has heretofore enabled only an intermittent melting operation, the metal material can be continuously melted and taken out.

Abstract: Furnace for the continuous melting of mixtures of oxides by direct induction at high frequency and a very short refining time and with a low energy consumption, comprising an intake (14) and a nozzle (15) for the continuous discharge of oxides into a metal crucible (3) having cold walls heated by a high frequency coil (5), characterized in that the height of the oxide bath is between 2 cm and 20% of the diameter of the metal crucible and in that the furnace hearth (4) is both transparent to the inducing magnetic field and sufficiently cooled to ensure the formation and maintenance of a protective solid crust at the bottom of the crucible.

Abstract: A method and apparatus for forming a stream of molten material. The apparatus includes a melt container having a bottom wall in which is formed an aperture. A funnel is adapted and constructed to receive molten material from the aperture in the container, and includes a plurality of fluid-cooled metallic segments. The funnel segments define an inner funnel contour that decreases in cross-sectional area from the inlet end to the outlet end of the funnel. An electrically conductive coil surrounds the funnel, and has a shape corresponding to the outer shape of said funnel. A source of medium-frequency current in selective electrical connection with the coil. The method begins with the step of providing a predetermined quantity of molten material in a melt container. A metallic funnel is provided in fluid communication with the melt container, and includes a plurality of fluid-cooled funnel segments. The method also includes the step of providing an electrically conductive coil surrounding the funnel.

Abstract: In the operation of a hot metallizing furnace for lengths of metal, in particular metal strip, in which the length of metal to be coated is passed from above through the upper zone of a smelt of a coating material located in a smelt container, the smelt container can be heated by means of an induction coil made up of partial coils arranged axially on top of one another. During hot metallizing the upper partial coil(s) is/are connected to a medium frequency source of electricity in a single-phase manner. For the removal of the deposits which accumulate in the lower area of the smelt vessel, the lower partial coil(s) is/are connected to a three-phase current mains frequency source of electricity. The agitated deposits are then removed from the smelt using a collecting vessel.

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: A method and apparatus for growing an extended length single crystal of a Group III-V or II-VI material such as GaAs by moving a crucible containing a seed crystal and precompounded crystal material encapsulated in a molten encapsulant preferably vertically in a multi-zone furnace between two furnace zones maintained at temperatures above the melting point of the encapsulant but below the melting point of the crystal material through an intervening short "spike" zone maintained at a temperature at least equal to the melting temperature of the crystal material to crystallize the precompounded crystal material with the seed crystal, and tipping the crucible in the furnace, e.g. by tipping the furnace with the crucible in it, to decant the encapsulant prior to recovering the crystal.

Abstract: A semiconductor wafer processing furnace includes an elongated processing chamber enclosing a first zone and a second zone extending along a first reference axis, and a wafer support assembly having a support member and associated translation elements for selectively translating the support member between the zones, along the first reference axis, in response to an applied position signal. Temperature elements control the first and second zones to have selected first and second temperatures, respectively. A controller applies the position signal to the translation elements, in response to an applied control signal representative of a desired temperature of the region surrounding the support member. Responsive to the position signal, the translation elements position the support member along the reference axis such that the temperature of the region surrounding the support member substantially matches the desired temperature.

Abstract: An inductive heating device for uniformly heating a workpiece at rest has a plurality of heating coil units disposed so as to surround the workpiece. The heating coil units are connected in parallel to a power source, and a transformer is used to vary the voltage across the terminals of the outermost units to increase the current flowing through these outermost units. The device, therefore, has a very short insufficient heating temperature zone attributable to an end magnetic flux effect.

Abstract: A direct induction furnace or device for melting a charge held in a cold sheath or shroud with electromagnetic confinement of the conducting portions of the charge. The cold shroud comprises a cylindrical sidewall, which is composed of a plurality of juxtaposed segments in the shape of a hairpin inductor, each formed by two parallel tubular conductors, which are insulated from each other along their entire interface with the exception of a transverse section which electrically and hydraulically connects one end of one of the sections to the adjacent end of the other section.

Abstract: Workpieces are heat treated as they are advanced through and tumbled within a rotary retort. The retort is heated by electrical current which is inductively induced by coils disposed in surrounding relationship with the retort. A flared distributor on the exit end of the retort causes the workpiece to dribble continuously out of the retort.