Abstract: Disclosed is a structure for insulating high temperature devices such as furnaces. The insulating structure comprises a shell enclosing a series of refractory, substantially parallel, spaced-apart sheets, one or more of which may be reflective. The insulating structure stores little heat, is compact, and is lighter than refractory brick.

Abstract: Disclosed is apparatus for reflecting incident radiative energy back to a source. The apparatus features at least two planar reflecting facets which intersect at an angle and which are mounted for adjustment of the angle between the adjacent facets. The facets are oscillated in phase to sweep the angle between .pi./2 and .pi./2-.delta. radians. The angle .delta. is selected so that the plane of maximum areal energy density crosses the plane which includes the source. This apparatus thus compensates for the effects of dispersion with known retroreflectors.

Abstract: Disclosed is a mold structure for casting large metallic parts such as ingots so as to avoid the formation of the "shrinkage pipe" which normally develops on the exposed top surface of such castings during their solidification. The structure comprises a cap for placement on a mold which includes a diaphragm having a front surface located to intercept radiation emitted from the top surface of the cooling metal mass and to reemit radiation back thereto, and a means for returning radiation emitted from the back surface of the diaphragm such as an infrared reflector or a stack of baffles. The cap may include means for cooling the reflective surface and suitable ports which allow the interior of the mold and cap to be evacuated. Portions of the mold adjacent its open top may be provided with insulation to prevent heat loss from the metal by conduction. Various means for providing make-up heat to the top surface of the metal mass may also be included in the structure.

Abstract: Disclosed is apparatus for subjecting a workpiece to a controlled temperature comprising a light-weight muffle of high diffusivity material having an interior high emissivity surface, an air cooled envelope surrounding the muffle having an infrared reflective interior surface, and a housing which maintains a vacuum in the space outside of the muffle. Heaters and temperature sensors are spaced about the muffle. The heaters are controlled by an electronic feedback control system which actuates the heaters in response to signals received from the temperature sensors. The apparatus is ideally suited for use in the controlled diffusion processing techniques employed in the fabrication of electronic devices because it applies on the order of 90% of the generated heat to the workpiece, can be rapidly heated up and cooled, and can maintain a selected temperature within narrow limits.

Abstract: An apparatus for transporting a workpiece at high temperature is provided with enclosure means substantially surrounding a workpiece supported, or gripped by, the apparatus. The enclosure includes an interior surface positioned to be exposed to the workpiece and formed from a material that is highly reflective of infrared radiation. Separate segments of the enclosure are movable relative to each other (e.g., hingedly connected to each other) to permit entry and removal of a workpiece. Provision is also made for introducing an inert atmosphere into the enclosure.

Abstract: Disclosed is a process and apparatus for recovering high temperature heat normally lost from materials that have been processed at high temperature, and for transferring this heat directly to materials about to be processed. The apparatus comprises a tunnel having an infrared radiation reflective interior surface through which cool incoming and hot exiting workpieces pass. The cross-sectional shape of the tunnel is elliptical, and the workpieces are moved along focal lines so that radiation emitted from hot workpieces is reflected at the interior surface, directed to cool workpieces, and absorbed. A furnace suitable for subjecting a workpiece to a controlled thermal cycle is also disclosed.

Abstract: Radiant energy emitted from a source (e.g., a door of, or a workpiece within, an industrial furnace), which would otherwise be lost, is recuperated by the placement of an array of reflective cells in the path of the emitted beam. Each reflective cell comprises multiple reflecting surfaces for reflecting the incident beam back toward the opening even if the beam is not perpendicular to any of the reflecting surfaces. The individual facets of each cell are shaped to reduce scattering losses. Additionally, secondary arrays of reflective cells can be employed to intercept, and thus recuperate, even the reduced amount of rays scattered from the primary array. Focusing techniques are employed to minimize dispersion losses.

Abstract: Radiant energy emitted from an opening (e.g., a door in an industrial furnace), which would otherwise be lost, is recuperated by the placement of an array of reflective cells in the path of the emitted beam. Each reflective cell comprises multiple reflecting surfaces for reflecting the incident beam back toward the opening even if the beam is not perpendicular to any of the reflecting surfaces. In a typical construction, the front face of a substrate is coated with a material (e.g., gold) that has a high reflectance in the infrared. A protective layer, which is transparent in the infrared, overlies that coating in order to prevent damage to the coating and to facilitate cleaning. Heat recuperators having dihedral and trihedral individual reflecting cells are described in detail.