Abstract: A sintered refractory product having a granulate bonded by a matrix and comprising, in percentages by mass based on the oxides, —more than 40% chromium oxide Cr2O3, —less than 50% aluminium oxide Al2O3, ?1% or more zirconium oxide ZrO2, of which at least 20% by mass is stabilised in the cubic and/or quadratic form, ?0.1% or more yttrium oxide Y2O3, acting as a stabiliser for the zirconium oxide ZrO2, —less than 1.9% hafnium oxide HfO2, the total content of chromium, aluminium and zirconium oxides Cr2O2+Al2O3+ZrO2 being greater than 70%.

Abstract: Provided is an air cooled combustion furnace system to effectively operate a combustion furnace for generation of heat energy via combustion of a solid fuel so as to optimize thermal efficiency. The combustion furnace system includes a combustion body structure provided with a hopper and having a combustion space for production of heat energy via combustion of a solid fuel, a cooling device integrally formed in multiple layers with the combustion body structure to cool the combustion body structure via distribution of air, a negative pressure induction device to create a negative pressure within the combustion body structure by suctioning air, a fuel supply device, a grate device constructed by coupling a plurality of grate segments to one another and serving to support the solid fuel being combusted, and a clinker removal device to remove clinkers generated during combustion of the solid fuel from the grate device.

Abstract: An apparatus for manufacturing front glass for an electronic device produced between an upper mold and a lower mold and having an at least partially curved surface, the apparatus including an inner tube 10 of a specific length and having an entrance portion for allowing the mold assembly for heat treatment to enter the inner tube and an exit portion for allowing the mold assembly after the heat treatment to exit; a conveyer belt for feeding a plurality of mold assemblies thereon, at specific speed in such a way as to pass through the inner tube; and a high temperature chamber 20 surrounding the inner tube between the entrance portion and exit portion of the inner tube and having a heat source for forming a high temperature atmosphere in order to form the front glass fed within the inner tube.

Abstract: A heating electrode assembly for a crystal growth furnace includes: a heat insulation board unit that is disposed between a furnace wall and a heater, that includes a first surface facing the furnace wall and a second surface facing the heater, and that is formed with a hole extending through the first surface and the second surface; an electrode unit that includes an electricity input portion mounted to the furnace wall, a post portion disposed in the hole, and an abutment flange connecting the post portion and the heater; and an electrical insulating unit including a tubular sleeve that is disposed in the hole and that surrounds the post portion, and a pad that is clamped between the abutment flange and the second surface.

Abstract: A vacuum oven or vacuum furnace is disclosed having a heat distribution sleeve that conforms to the shape of an interior heating chamber. The heat distribution sleeve may be of generally annular shape, like a ring, and located in a substantially regularly spaced and offset relationship from a heating element located within walls adjacent the interior heating chamber. The heat distribution sleeve includes a thermal conductive material which absorbs and re-radiates heat emitted from the heating element, thereby providing more consistent and regular radiation fields for heating treating a work piece that is loaded on a work holding tray and, upon the vacuum oven being in an operational position, the work piece is located within the furnace chamber.

Abstract: A heating electrode assembly for a crystal growth furnace includes: a heat insulation board unit that is disposed between a furnace wall and a heater, that includes a first surface facing the furnace wall and a second surface facing the heater, and that is formed with a hole extending through the first surface and the second surface; an electrode unit that includes an electricity input portion mounted to the furnace wall, a post portion disposed in the hole, and an abutment flange connecting the post portion and the heater; and an electrical insulating unit including a tubular sleeve that is disposed in the hole and that surrounds the post portion, and a pad that is clamped between the abutment flange and the second surface.

Abstract: A vacuum oven or vacuum furnace is disclosed having a heat distribution sleeve that conforms to the shape of an interior heating chamber. The heat distribution sleeve may be of generally annular shape, like a ring, and located in a substantially regularly spaced and offset relationship from a heating element located within walls adjacent the interior heating chamber. The heat distribution sleeve includes a thermal conductive material which absorbs and re-radiates heat emitted from the heating element, thereby providing more consistent and regular radiation fields for heating treating a work piece that is loaded on a work holding tray and, upon the vacuum oven being in an operational position, the work piece is located within the furnace chamber.

Abstract: A high-temperature furnace for melting materials, e.g. silicon, wherein the furnace comprises a vessel having a wall which defines an inner chamber. A crucible containing the material to be melted is positioned inside of the chamber and heating means is arranged around the crucible. An insulation package is provided in the chamber for protecting the vessel wall from the heat generated by said heating means. Specifically, the package comprises a support ring of insulation mounted in the chamber, a sleeve of insulation supported on the ring and extending upward between the heating means and the vessel wall, a catch tray adapted to receive any material which may leak from the crucible during heating mounted through the support ring, and a top and a lower layer of insulation to thermally seal the crucible within the package during heating.

Abstract: The method of making a single crystal, especially a CaF2 single crystal, includes tempering, in which the crystal is heated at <18 K/h to a temperature of 1000° C. to 1350° C. and held at this temperature for at least 65 hours with maximum temperature differences within the crystal of <0.2 K. Subsequently the crystal is cooled with a cooling rate of at maximum 0.5 K/h above a limiting temperature between 900° C. to 600° C. and then further below this limiting temperature at maximum 3 K/h. The obtained CaF2 crystals have refractive index uniformity <0.025×10?6 (RMS) in a (111)-, (100)- or (110)-direction and a stress birefringence of less than 2.5 nm/cm (PV) and/or a stress birefringence of less than 1 nm/cm (RMS) in the (100)- or (110)-direction. In the (111)-direction the stress birefringence is <0.5 nm/cm (PV) and/or the stress birefringence is <0.15 nm/cm (RMS).

Abstract: The present invention provides a radiation apparatus with capability of preventing heat convection, which comprises a blackbody furnace having a cavity therein and an air pressure adjusting unit. The air pressure adjusting unit coupled to the blackbody furnace for adjusting the air pressure of the open end of the cavity according to the temperature difference between the cavity and the outside environment. By means of the design of the present invention, it is capable of preventing heat convection between the cavity and the outside environment by utilizing the air pressure adjusting unit for controlling the air pressure status around the open end of cavity such that the blackbody furnace is stable for services of calibrations and tests.

Abstract: A fixture (30) adapted to permit the heated exchange of a liner (14) from an operating vertical furnace (10). The fixture is adapted to secure to the base of the liner (14) to both unlock and lower the heated liner, such as a silicon carbide liner, at an controlled rate. The fixture is also adapted to elevate a new liner into the operating vertical furnace at a controlled rate to control the rate of heating of the liner as it is inserted into the operating vertical furnace. The fixture includes an inner ring (34), a low-friction Teflon® ring (36), and an outer ring (38) permitting the rotation of the inner ring within the outer ring. Advantageously, the low friction ring comprises a flanged portion and a vertical portion allowing rotation of the inner ring within the outer ring even when elevated at extreme temperatures exceeding 500° C.

Abstract: A system for heating optical members includes a thermally-conductive inner housing defining an interior volume for receiving an optical member to be heated, a thermally-insulative outer housing at least partially containing the thermally-conductive inner housing, and a heating structure disposed outside the inner housing and configured to provide heat through the thermally-conductive inner housing and into the interior volume defined by the inner housing.

Abstract: A vacuum oven for decontaminating items, a system incorporating multiple such vacuum ovens and a method of operating such system are provided. The ovens are portable. They can have a vacuum drawn in them and can be heated by being coupled to a vacuum and a power source, respectively at a first location and then be decoupled from the vacuum and power sources and moved to a second location such as a glove box or clean room while still maintaining a vacuum.

Abstract: A method rebakes and graphitizes pitch-impregnated carbon bodies in an encapsulated Castner-type lengthwise graphitization furnace in one step. A furnace shell is constructed of element modules and can carry out the method. A furnace utilizes the furnace shell. The oxygen content in the interior of the furnace is kept below 4% by volume. The method is carried out under atmospheric pressure or at pressures that differ only slightly from the atmospheric pressure.

Abstract: A system for heating optical members includes a thermally-conductive inner housing defining an interior volume for receiving an optical member to be heated, a thermally-insulative outer housing at least partially containing the thermally-conductive inner housing, and a heating structure disposed outside the inner housing and configured to provide heat through the thermally-conductive inner housing and into the interior volume defined by the inner housing.

Abstract: Disclosed is a thermal insulation to be inserted between two structures, surfaces, walls or the walls of components which are to be insulated. The thermal insulation consists of an plurality of hollow spheres made up by loose hollow spheres or by hollow spheres which are interconnected by sintered contacts. The ratio of the outer diameter of the hollow spheres to their wall thickness is 5 300. The hollow spheres are made of silicides, silicide composites, metals and intermetals and the alloys thereof, ceramics or glass. When the walls of the hollow spheres have a closed porous structure, the inner pressure in the hollow spheres is between 0 to 0.1 that of the surrounding air pressure at room temperature.

Abstract: The invention relates to a sintered shaped body comprising a matrix material that contains an aluminum oxide/chromium oxide mixed crystal and an additional mixed crystal selected from at least one mixed crystal according to one of the general formulas La0.9Al11.76−xCrxO19, Me1Al11−xCrxO17, Me2Al12−xCrxO19, Me2′Al12−xCrxO19 and/or Me3Al11−xCrxO18, wherein Me1 stands for an alkali metal, Me2 represents an alkaline earth metal, Me2′ stands for cadmium, lead or mercury and Me3 represents a rare earth metal and x has a value ranging from 0.0007 to 0.045.

Abstract: The present invention is a heat insulating material being a single unit having superior insulating performance as well as sufficient mechanical strength itself to constitute furnace walls, an electric heating unit having the heat insulating material and a method of manufacture of the heat insulating material and the electrical heating unit. The heat insulating material of the present invention includes an outer layer having mainly refractory inorganic fibers and a core layer supported within the outer layer. The outer layer has greater mechanical strength than the core layer. The core layer has a composition having a better insulating performance than the outer layer and extends in a plane substantially perpendicular to the thickness of the heat insulating material. The electrical heating unit of the present invention has a heating element embedded in the heat insulating material.

Abstract: A large diameter quartz crucible with an inner diameter of 22 inches or more comprises an opaque silica glass outer layer having bubbles of 10 .mu.m to 250 .mu.m in diameter and 5 mm to 20 mm in thickness and a transparent silica glass inner layer having 0.5% or less in a bubble content and 0.3 mm or more in thickness which is molten and integrated with an inner surface of the outer layer. The outer layer has an OH group concentration of 80 ppm or less and the gas pressure in a bubble in the outer layer is lower than atmospheric pressure so that a volume expansion ratio of the bubble is minimized when being heated in condition of pulling a single crystal.

Abstract: A high temperature vacuum furnace which has an internal thermal insulation system to reduce heat losses and an external vacuum vessel which is designed to safely dissipate all heat generated within the furnace to the surrounding air. The vacuum vessel wall remains at a low enough temperature to ensure structural integrity and at a low enough temperature to protect elastomer seals without the use of water cooling.

Abstract: Dual electric/gas heating in a crucible melting furnace with segmental lining, and lining and segments of linings for same, are disclosed.

Abstract: A fiber drawing apparatus is provided with an improved fiber draw furnace wherein an inner zirconia tube is surrounded by a radially-spaced annular insulating region of magnesia within a silica beaker. While the magnesia has a melting point approximately the same as zirconia, the electrical conductivity of magnesia is substantially lower, enabling it to withstand higher RF power. Moreover magnesia is more soluble than zirconia in silica, reducing the likelihood of particulate contamination of the fiber.

Abstract: An apparatus and a method for electrically heating a refractory lined process vessel or reactor by directly passing current through an electrically conductive refractory lining using electrical heating assemblies incorporating a resilient, convoluted nickel conductor. When the heating assemblies are attached to the electrically conductive refractory lining, an impressed voltage causes current to flow between the heating assemblies causing the refractory lining to be heated resistively.

Abstract: An induction furnace for heating a portion of an optical preform in order to draw an optical fiber therefrom. The furnace includes a tubular susceptor which is disposed centrally within a housing. The electromagnetic field from a high frequency coil surrounding the susceptor is coupled to the susceptor to heat and reflow a portion of the preform. A cellular refractory tubular insulator is located between the coil and the susceptor.

Abstract: A heat shielding cladding for walls, ceilings, or similar surfaces, especially of industrial furnaces, including butted together parallelepipedal modules that are secured to the wall and comprise a plurality of held together and compacted fiber mat webs that are prestressed in a direction parallel to the wall. Adjacent modules are held together in a permanently flexible bond on non-prestressed sides thereof by at least one filamentary, temperature-resistant binder that is guided, without kinking, from a surface of the heat shielding cladding that is remote from the wall to the wall.

Abstract: A non-fibrous ceramic liner for induction furnaces is provided by vertically stackable ring-shaped liner segments made of ceramic material in a light-weight cellular form. The liner segments can each be fabricated as a single unit or from a plurality of arcuate segments joined together by an interlocking mechanism. Also, the liner segments can be formed of a single ceramic material or can be constructed of multiple concentric layers with the layers being of different ceramic materials and/or cellular forms. Thermomechanically damaged liner segments are selectively replaceable in the furnace.

Abstract: A heating apparatus including a process tube in which the target objects are arranged in an internal heating area and a multilayer insulating structure arranged so to enclose the process tube. At the inner face of an inorganic molded structure of bulk density 0.3-0.8 g/cm.sup.3, an inorganic insulating layer of bulk density 1.0-2.0 g/cm.sup.3 covered on the inner face or all faces thereof by inorganic cloth is provided to form the multilayer insulating structure. The inner face of the inorganic insulating layer is used to support a heat generating means. A cooling means is also provided for cooling the flat heating area of the process tube. As a result, a heating apparatus of the present invention is provided that features excellent endurance against spalling, deterioration and chemical reaction, and which is capable of long term stability with respect to temperature increase and decrease.

Abstract: A furnace lining is formed by a plurality of lining bricks. The bricks have surfaces defining an internal surface of the lining that is to face the interior of the furnace and to receive therefrom radiant heat. At least one depression is formed in the lining and opens onto the surface through an opening. The depression has internal wall surfaces that are geometrically configured to cause radiant heat from the furnace interior that impinges on a first internal wall surface to be reflected thereby and to impinge therefrom onto a second internal wall surface. Thus, the heat will be absorbed by the bricks of the lining, and such heat will be emitted thereby from the inner surface thereof.

Abstract: A vertical gradient freeze single crystal growing apparatus utilizing a direct monitoring furnace which is possible to obtain rapid high temperature heating and uniform temperature distribution by using direct monitoring furnace as a higher temperature part furnace provided with double quartz tube applied with gold thin film, and also capable of observing entire process of single crystal growing directly by naked eye.

Abstract: A high frequency core and coil electric metal melting furnace is shown. This furnace has a lined channel in its inductor for carrying the molten metal. The invention provides an improved inductor for a core and coil furnace that is not subject to leakage of the molten metal from the channel into the rammed refractory support bed for the channel which leakage otherwise shortens the lift of the furnace. Also a method of lining the channel in the inductor for carrying the molten metal which forms the core is disclosed.

Abstract: A furnace comprising a cylindrical heater and a cylindrical insulation around the heater, wherein the insulation has anisotropy in heat transfer and a direction along which the thermal conductivity of the insulation is small corresponds to a direction along which temperature gradient within the insulation is steep. The insulation is formed of plural anisotropic parts arranged such that the direction along which thermal conductivity is low of one part blocks heat transfer from a direction along which the thermal conductivity of another part is high.

Abstract: A lining for use in an aluminum reverberatory furnace or the like for heating molten aluminum in a cavity which cavity is formed by a roof, sidewalls and a bottom which are to be lined with refractory materials. The lining comprises a band of hot face refractory material around the interior periphery of the cavity sidewalls for contacting molten aluminum in the furnace at the normal operating levels of the upper surface of the molten aluminum. A layer of backup refractory material is interposed between the furnace shell and the band of hot face refractory material.

Abstract: A refractory product is shown in the form of a dense sintered alumina-chromia, zirconia-alumina-silica, zirconia-alumina body, or zirconia-chromia-alumina having less than about 8% of homogeneously distributed closed porosity formed by sintering an intimate interdispersion of fine particles of alumina-chromia, zirconia-alumina-silica, zirconia-alumina, or zirconia-chromia-alumina.

Abstract: A support plate is used, together with the shell of a vessel for the holding and/or refining of aluminum, in combination with a refractory sheet and a metal heating element container positioned in a graphite block to protect said heating element and to thus extend the life of said heating element. Oxidation of the graphite block is precluded, as is the attack upon the heating element by chlorides passing through the pores of said graphite block.

Abstract: A furnace with the end portions of a heater supporting anchor rod embedded in the rigid sidewall insulation of the furnace. The anchor rods do not deflect under the weight of the heaters and the entire weight of the anchor rods and heaters is supported by the sidewall insulation.

Abstract: The electric resistance heating elements of a heat treating furnace are suspended within a work chamber by hanger rods threaded into nuts which are welded to the inside of the outer wall of the chamber to avoid the need for forming holes through the outer wall. Spacers are supported by adjacent hanger rods and hold thin radiation shields in spaced relation over the entire span extending from rod-to-rod.

Abstract: A characteristic feature of the furnace disclosed in the present invention is the presence therein of additional current-carrying elements with the free end thereof sunk relative to the effective area of the furnace brickwork. The elements are connected with the terminals of a power source of the opposite polarity with respect to the connection of the main current-carrying elements of a corresponding operating area.

Abstract: A heat treating furnace in which an electrical resistance heating element is disposed in a chamber and is energized by way of a power feed through conductor which extends slidably through the wall of the furnace. An insulating washer and a retaining washer may be installed on and removed from the inner end portion of the feed through conductor from inside the furnace without either removing the conductor from the furnace wall or disconnecting the conductor from the heating element. A power terminal block and inlet and outlet lines for cooling water are adapted to be quickly and easily disconnected from the outer end portion of the feed through conductor to permit the conductor to be easily pulled inwardly through the furnace wall for servicing.

Abstract: An improved heat treatment furnace and method of constructing the same is enclosed wherein the duct work of the furnace includes directional vanes and adjustable plenum vents and chamber dampers to yield a substantially uniform air flow pattern within the heat treatment chamber. The plenum vents and chamber dampers are provided with remotely operable actuating means which permit rapid adjustment of the vents and dampers from the exterior of the furnace during the heat treatment process and/or furnace certification. The furnace additionally incorporates a novel ribbon heating element/fiber insulation assembly and construction method which substantially reduces furnace operating costs and insures that only convectional heat transfer (as opposed to radiant) occurs within the heat treatment chamber of the furnace.

Abstract: An apparatus and method for insulating an electric furnace having resistive heating elements in which precast support rings comprising studs, a ring and a plurality of rods are welded to a furnace wall alternatively with placing batts of ceramic fiber insulation over the support rings against the furnace wall to form an inner insulated furnace wall. The rods have rotatably mounted removable ceramic hangers having an inner hook for supporting a serpentine electric heating element such that there is no danger of a short circuit with the metal support ring if the hanger fails.

Abstract: A fused salt reduction cell for producing aluminum comprises a cathode pot having an outer steel shell supported on or by metal structural parts, a thermally insulating layer and an inner lining which is of carbon, is electrically conductive and is resistant to attack by the molten aluminum and the electrolyte.In the region of the electrolyte there is a layer which runs horizontally around the cell dividing the carbon lining into a lower part and an upper part. This layer is of a material which is resistant to the electrolyte at temperatures up to 1000.degree. C. and has a much lower shear strength than that of the carbon lining.

Abstract: A high temperature box annealing furnace for metallic coil annealing practices. The furnace comprises a fixed base and a removable bell capable of achieving a sealed relationship with the base. The interior of the bell side walls, end walls and roof are lined with ceramic fiber insulation and are provided with electrical resistance heating elements. The heating elements are divided into at least two separately controllable zones, a first zone including the heating elements mounted on the bell roof and the upper portions of the bell side and end walls and a second zone including the heating elements mounted on the lower portion of the bell side and end walls. The base comprises a steel framework supporting a cast refractory base member configured to support one or more coils. Each coil is provided with a cover and the cast refractory base member provides a sand seal for the lower edge of the covers. The cast refractory base has an atmosphere inlet for each coil positioned at the center or eye of the coil.

Abstract: A kit is provided that is especially designed for relining electric furnaces of circular cross section and relatively standard dimensions. Prefabricated rings of ceramic fibers bonded together with an inorganic binder form integral, rigid bodies that can be easily handled. Some rings are provided with protruding hangers at predetermined desired locations, spaced around the interior circumference of the ring. The hangers are each formed with an upturned hook at one end of a short intermediate section that supports the heating ribbon and with a straight, elongated section at the other end thereof which is oriented at an angle of between about 115.degree. and about 155.degree. thereto. The elongated ends fit into downwardly inclined holes which are correspondingly oriented at an angle between 25.degree. and 65.degree. to the interior, vertical, circumferential wall of the ring.

Abstract: A furnace includes a jacket (1) which is removably mounted to a bottom plate construction (2) so that the jacket can be mounted on any one of a number of the bottom plate constructions. A cap (3) is removably secured on an upper part of the jacket by latches (4), and electric resistance elements (16, 22) are mounted adjacent to an inner surface of the jacket by a plurality of strips (14) having pins (15) thereon. Since the jacket is removably mounted on the bottom plate construction, after a burning process has been completed, the jacket can be removed from the bottom plate construction and placed on another similar bottom plate construction to initiate another burning process while the products which have been previously burned are allowed to cool. In the event that quick cooling of the products is not desirable, the cap may be removed and replaced by a simple, intermediate cap so that the products are allowed to cool more slowly.

Abstract: A suspension system for an electric heating element array of a furnace comprises first and second suspension arms with a hanger element support member extended therebetween. The suspension arms are pivotally mounted to a support rod passing through the insulation module and linked to the furnace wall via the module attachment system. Upon affixation of the insulation module to the furnace wall the suspension arms are pivoted until the support member contiguously transverses the hot face of the module. A plurality of hanger elements are suspended from the support member with the heating elements then hung therefrom.

Abstract: An electrical resistance furnace which includes a number of electrical resistance heating elements arranged around the sides and surrounding a space containing a crucible or similar container to be heated, the elements being supported at least at their ends by fire-brick material and being surrounded by heat insulation, wherein both ends of each resistance element extend through apertures in the fire-brick material so that by removing part of the heat insulation access may be gained to both ends of the element from the exterior of the furnace to permit removal and repair or replacement of the element.

Abstract: The present invention is directed to an improved resistance welding pin especially adapted for fastening of batts of insulating material to metallic air conduits, such as the ducts of air conditioning and heating systems. The pin is characterized by a novel corrugated shank portion extending between the head of the pin and the sharpened tip which functions, inter alia, to dissipate the heat generated in the shank during welding, with a plurality of attendant advantages.

Abstract: The present invention is directed to graphite shields (or shields of other materials which may react chemically or be oxidized in a vacuum furnace but which when condensed do not readily conduct electricity) or graphite shield liners used to protect electrical insulating devices from having electrical shorting path means develop thereon.

Abstract: This invention relates to an electrical element support system that utilizes a series of ceramic hanger elements of generally rectangular cross-section which are adapted to be inserted into a clip which is attached by welding or bolting to the furnace wall. The clip provides bearing surfaces which match surfaces on the hanger element to provide support for the electrical element which is carried at the end of the support. The outer end of the hanger element generally has a hook or other device which is adapted to hold a particular electrical heating element.

Abstract: A flexible cover for a carbon bake pit has a flexible, expanded metal backing to which is attached a blanket of insulating ceramic fibers. This construction allows the cover to flex in order to conform to the surface of the material in the pit. Lifting means are attached to the expanded metal backing in a manner so as to permit this flexibility.