Abstract: A modular heating element that facilitates removal and replacement without disassembly of a furnace provides a precisely controllable process temperature in the range 1000-1400 degrees centigrade. The configuration of the heating element is linear rather than coiled, and the temperature is monitored directly by measuring the electrical resistance of KANTHAL®, or other like Fe Cr Al wire encased in an aluminum ceramic sleeve that provides mechanical support and seals the heating element wire against oxidation, thereby increasing operational temperature and prolonging service life.

Abstract: Metallurgical grade silicon or high purity silicon beads developed from a fluidized bed process are melted in a cooled aluminum crucible, such that a non wetted interface is created between the molten silicon and a cooled supporting substrate that includes a surface layer of substantially inert aluminum oxide. It is believed that the molten silicon does not wet the surface of the supporting substrate and the surface of the supporting substrate does not chemically interact with the silicon. It is shown that, in spite of the enormous temperature difference, molten silicon (ca. 1450° C.) can be stabilized, by appropriate energy control, in direct (but non-wetted) contact with cold (ca. 40° C.) material such as aluminum.

Abstract: A pinch valve is described wherein the critical flow path is modified to form a space between two opposing metal disks that transition between an open and a closed state. The disks are characterized by a spring constant and act like a diaphragm. A closure force is applied externally to completely close the disks and truncate flow, while providing a substantially perfect seal. Removal of the external force enables the disks to spring open and initiate flow. The pinch valve advantageously eliminates valve bodies, dead space, moving parts and seals, such as elastomers, that are subject to wear and corrosion.

Abstract: A furnace incorporating a novel thermal design is disclosed. Heating element temperature is reduced compared to conventional designs while providing a precisely controllable process temperature in the range 1000-1400 degrees centigrade. A plurality of Kanthal heating elements are arranged in a planar array as close to the work as possible, thus approximating an isothermal condition with respect to the work. The process chamber is made of aluminum and its internal surfaces are highly polished to reflect heat. The chamber walls have built in active cooling to carry away non-reflected heat and preserve high reflectivity. The heating elements are modular to facilitate removal and replacement without disassembly of the furnace. The configuration of the heating elements is linear rather than coiled and the temperature is monitored directly by measuring the electrical resistance of the Kanthal wires.