Abstract: An induction heating apparatus and method of use wherein the apparatus includes two poles, each pole comprising a pair of spaced apart coils wherein at least one of a spacing between the poles and the pole pitch is adjustable to control the power density transferred to a workpiece across its width. In some embodiments, movable flux shields are also adjusted to control power density transferred along edge portions of the workpiece.

Abstract: Induction heating apparatus and methods are presented for pipe end heating using a solenoid coil to heat a controlled length of a pipe workpiece by adjusting the relative positions of the solenoid coil with a flux diverter positioned relative to the pipe end to divert flux from the coil to control inductive heating of the pipe workpiece end.

Abstract: Induction heating apparatus and methods are presented for pipe end heating using a solenoid coil to heat a controlled length of a pipe workpiece by adjusting the relative positions of the solenoid coil with a flux diverter positioned relative to the pipe end to divert flux from the coil to control inductive heating of the pipe workpiece end.

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 continuous- or intermittent-melt induction furnace useful for heating and/or melting semi-conductor or other materials includes an induction coil, a susceptor switchable between open and closed electric circuit modes, and a crucible. The susceptor is inductively or resistively heated in the closed circuit mode and transfers heat to material in the melting cavity to make it susceptible to inductive heating. The susceptor is then switched to the open circuit mode and the susceptible material is directly inductively heated to melt remaining solid material. A cone-shaped flow guide in the melting cavity improves molten material flow to improve the ability to draw small-particle material into the melt and increase crucible life due to improved heat uniformity. A trap passage communicating with the melting cavity and an exit opening in the crucible allows the flow of material through the exit opening to be controlled by pressure differentials on either side of the trap passage.

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 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: 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 casting system includes a filtration assembly including a filter vessel housing spaced filters pre-heated to a temperature approximating a pouring temperature of molten material to be filtered to prevent breakage of the filter due to thermal shock from contact with the molten material. Preferably, an induction coil is used to inductively heat a susceptor adjacent the filter vessel or inductively heat filters which themselves serve as susceptors. Typically, the filter vessel is disposed below a pouring vessel and above a mold, pour cup and any sprue system used and is heated independently from the same. The filters are heated during pouring to facilitate flow of the molten material therethrough whereby very fine filters may be used. Spacing of the filters enhances flow control and allows a head of molten material to form whereby dross floats to the top of the head to prevent its entry into the mold.

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: A continuous- or intermittent-melt induction furnace useful for heating and/or melting semi-conductor or other materials includes an induction coil, a susceptor switchable between open and closed electric circuit modes, and a crucible. The susceptor is inductively or resistively heated in the closed circuit mode and transfers heat to material in the melting cavity to make it susceptible to inductive heating. The susceptor is then switched to the open circuit mode and the susceptible material is directly inductively heated to melt remaining solid material. A cone-shaped flow guide in the melting cavity improves molten material flow to improve the ability to draw small-particle material into the melt and increase crucible life due to improved heat uniformity. A trap passage communicating with the melting cavity and an exit opening in the crucible allows the flow of material through the exit opening to be controlled by pressure differentials on either side of the trap passage.

Abstract: A continuous- or intermittent-melt induction furnace useful for heating and/or melting semi-conductor or other materials includes an induction coil, a susceptor switchable between open and closed electric circuit modes, and a crucible. The susceptor is inductively or resistively heated in the closed circuit mode and transfers heat to material in the melting cavity to make it susceptible to inductive heating. The susceptor is then switched to the open circuit mode and the susceptible material is directly inductively heated to melt remaining solid material. A cone-shaped flow guide in the melting cavity improves molten material flow to improve the ability to draw small-particle material into the melt and increase crucible life due to improved heat uniformity. A trap passage communicating with the melting cavity and an exit opening in the crucible allows the flow of material through the exit opening to be controlled by pressure differentials on either side of the trap passage.

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: A continuous- or intermittent-melt induction furnace useful for heating and/or melting semi-conductor or other materials includes an induction coil, a susceptor switchable between open and closed electric circuit modes, and a crucible. The susceptor is inductively or resistively heated in the closed circuit mode and transfers heat to material in the melting cavity to make it susceptible to inductive heating. The susceptor is then switched to the open circuit mode and the susceptible material is directly inductively heated to melt remaining solid material. A cone-shaped flow guide in the melting cavity improves molten material flow to improve the ability to draw small-particle material into the melt and increase crucible life due to improved heat uniformity. A trap passage communicating with the melting cavity and an exit opening in the crucible allows the flow of material through the exit opening to be controlled by pressure differentials on either side of the trap passage.

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: A method and apparatus for accelerated cooling of a furnace such as a furnace containing a susceptor. Cooling gases are split whereby a first percentage are provided to cool the furnace while a second percentage are provided to assist in cooling the heated cooling gases after cooling the furnace, whereby the percentages are changed throughout the process. The system further provides for unique cooling flow arrangement in the furnace which promotes maximum heat transfer through swirling.

Abstract: An induction melting furnace includes a detection system for sensing metal penetration into a wall of the furnace depending upon detecting heat flow from the hearth to the furnace. The furnace includes a crucible including a refractory lining for holding molten metal, a coil for inductively heating the molten metal, and a power supply for supplying energy to the coil and the detection system. An electrode system is interposed between the coil and the lining comprising a sensing mat housing conductors receiving a test signal from the power supply, wherein the sensing mat includes a temperature sensitive binder that varies conductivity between the conductors in response to heat penetration through the lining. The sensing mat is preferably comprised of flexible phillosilicate mica for enhanced thermal conduction and the binder comprises an organic resin compound which carburizes at a predetermined elevated temperature.