Abstract: A method of producing near net shape fusion cast refractories. The method includes the steps of continuously introducing refractory particles into a melting furnace, rapidly heating the particles, depositing the heated particles into a melt pool, continuously introducing the molten material into a mold, and continuously withdrawing a solidified body from the mold as the molten material continually solidifies. The above stated method produces a fusion cast refractory having a generally random, fine, uniform microstructure; uniform chemistry; and generally evenly distributed closed pores.

Abstract: An impeller for a molten metal pump having a cup-shaped body comprised of a sidewall and a closed end portion that define a cavity. A plurality of shear vanes extend radially from the outer surface of the impeller, particularly from the end portion of the impeller. The impeller also has a plurality of openings extending laterally through its sidewall, wherein the openings have center lines disposed parallel to lines extending radially from the center of the cavity. The openings may be equidistantly spaced about the periphery of the sidewall. The impeller may also be comprised of a bearing member forming a portion of the sidewall.

Abstract: A process for the manufacture of high purity, ultra-fine aluminum nitride powder by the carbo-nitridization of alumina. Agglomerates uniform in both size, chemical composition and porosity are formed containing a stoichiometric mixture of alumina and carbon with the addition of a small amount of catalyst. The agglomerates are furnaced in a controlled manner in a well-mixed reaction vessel to achieve a uniform and consistent level of conversion. Milling of the as-reacted agglomerates under a controlled atmosphere will produce high purity, micron sized aluminum nitride powder.

Abstract: Improved inorganic ceramic papers comprising heterogeneous grades of ceramic fibers, namely small, high surface area fibers and at least one larger, lower surface area ceramic fiber are bonded into a matrix with the aid of an inorganic binder system having at least one metal oxide with an average particle size below 200 nm. Multiple different grades of inorganic ceramic fibers and small particle size inorganic binders impart good tensile strength and flexibility characteristics in the same sheet.

Abstract: Metal particles are melted by mixing them with molten metal contained in a bath. A shaft-supported, rotatable impeller is immersed into the molten metal and rotated so as to establish a vortex-like flow of molten metal. Metal particles are deposited onto the surface of the molten metal in the vicinity of the rotating impeller. The particles are submerged substantially immediately after being deposited onto the surface of the molten metal. The impeller includes a thin rectangular prism having sharp-edged corners and vanes that extend upwardly from the prism. The impeller also can be used to disperse gas into the molten metal by pumping the gas through a bore extending the length of the shaft and out of the impeller along the lower surface of the impeller. The gas is sheared into finely divided bubbles as it rises along the sides of the impeller.

Abstract: A molten metal filter includes a refractory plate having an opening therethrough. A refractory filter element is attached to the refractory plate and projects therefrom, the exterior surfaces of the filter element generally defining a rectangular prism. The filter element is hollow so as to define an interior cavity. The filter element includes an opening in that portion of the filter element that is attached to the refractory plate, the opening surrounding the opening in the refractory plate such that fluid communication is established between the cavity and the opening in the refractory plate. In the preferred embodiment, a plurality of filter elements are provided, which filter elements are connected to the refractory plate such that adjacent sides of the filter elements are oriented vertically and are disposed generally parallel to each other.

Abstract: A process and apparatus for the manufacture of high purity, ultra-fine aluminum nitride powder by the carbo-nitridization of alumina. In the method, agglomerates uniform in both size, chemical composition and porosity are formed containing a stoichiometric mixture of alumina and carbon, and a small amount of catalyst, and furnaced in a controlled manner in a well-mixed two chamber reaction vessel having optional top or bottom fluidizing gas feed to achieve a uniform and consistent level of conversion. Milling of the as-reacted agglomerates under a controlled atmosphere will produce high purity, micron sized aluminum nitride powder. The reactor is an automatically controlled fluid bed reactor for treatment of refractory materials with a hot fluidizing gas having a two chamber design in which the lower furnace chamber and reactor bed are removable from the bottom of the reactor. With unique reactor, unusually high reaction temperatures of up to 2000.degree. C. are obtainable.

Abstract: A drive system for impeller shafts includes a coupling that has a universal joint that is lubricated under all operating conditions. A housing is connected to the universal joint, which housing includes a hollow end portion adapted to receive the non-threaded end of an impeller shaft. A threaded stud projects from the end of the shaft and into the housing where the stud is secured by means of a nut. The nut is readily accessible to the user so that the axial position of the shaft can be adjusted without difficulty. The nut is releasably held within the housing so that the shaft and stud, with nut attached, can be quickly disconnected from the coupling. The invention also includes a modified "square drive" configuration for the ends of the shaft that is extremely strong and enables the shaft to be connected to the impeller and the coupling very easily.

Abstract: A molten metal pump includes an impeller disposed at the end of an elongate drive shaft. The drive shaft is disposed within an elongate, hollow post. The impeller and the end of the post are adapted to be immersed in molten metal. An inert gas is conveyed through the gap between the outer surface of the drive shaft and the inner surface of the post, which gas is discharged into the molten metal in the vicinity of the impeller. Because the drive shaft is insulated from the molten metal, it can be made of a durable material such as steel; because the post is stationary relative to the molten metal, the metal is stirred only by the impeller, and not by the drive shaft. The invention includes other features such as a quick disconnect capability and a radial adjustment capability.

Abstract: A molten metal pump includes a filter that prevents ingestion of foreign material such as dross from molten metal within which the pump is immersed. The filter is a large structure that is secured to the base of the pump surrounding the pump's inlet. The filter forms a cavity adjacent the pump's inlet. The filter has a low porosity while maintaining a high flow rate for the pump. The filter is a semi-toroidal structure that is attachable to a pump base having an upper inlet. The filter surrounds the pump's inlet. The filter includes a central opening through which access can be had to the pump's impeller for purposes of inspection, repair, or replacement without disturbing the attachment between the filter and base.

Abstract: Apparatus for making ceramic tubes from a mixture that includes ceramic powder. The mixture is extruded through a die to form a tube. The tube is passed through an open-ended dryer, calciner, transition zone, sintering furnace, and cooler. Thereafter, the tube is cut to the desired length (which may be very long). The quality of the tube is enhanced by applying a vacuum to the mixture prior to extrusion. For tubes made of non-oxide ceramics, an inert atmosphere is maintained both inside and outside the tube in all sections of the equipment that operate above 200.degree. C. A controlled tension is applied to the tube by means of first pinch rolls disposed downstream of the dryer and second pinch rolls disposed downstream of the cooler.

Abstract: A moldable refractory composition containing from about 42 to about 83% by weight of a liquid vehicle, such as water; from about 13 to 50% by weight of ceramic fiber; from about 0.5 to 7% by weight of an inorganic binder derived from an inorganic colloidal dispersion having active hydroxyl groups capable of reacting with hydroxyl groups of the ceramic fiber; and from about 0.5 to 5% by weight of a high molecular weight organic resin which serves multiple functions including tackifier of the wet composition, cohesiveness of the wet composition, appropriate rheology of the wet composition to provide shelf life and a wide range of applications and in dry composition to provide green strength. Also described is the method of manufacture for the subject refractory moldable composition.

Abstract: The filtration of molten ferrous metal is accomplished by providing a porous ceramic filter preferably comprising particles of alumina and partially stabilized zirconia that are spaced by interconnected cells to form circuitous and tortuous pathways throughout the ceramic body. The filter is a disc-like structure that can have different surface configurations such as corrugations or a waffle design. The filter can be flat-surfaced with an array of cylindrical openings or counterboard openings extending completely through the filter, or with openings extending partially into the filter from the upper and lower sides of the filter. Several relatively thin filters can be arranged in tandem, if desired.

Abstract: As an article of manufacture an intumescent conforming mounting pad for fragile structures comprised of at least two plys of intumescent sheet material adhesively bonded together over a predetermined part of their adjoining faces said plys and being offset a predetermined amount lengthwise whereby said pad can be bent around a fragile structure and the ends can be joined without cracking or buckling.

Abstract: A method for controlling the magnesium content of molten aluminum includes the steps of injecting a halogen gas into the molten aluminum, sampling a portion of the resulting gases evolved from the molten aluminum, detecting the presence of constituents in the sampled gases and/or characteristics of the sampled gases indicative of the imminent evolution of unreacted halogen gas, and adjusting the rate of halogen gas injection to approach the point where unreacted halogen gas is about to be evolved. In the preferred embodiment, the halogen gas is chlorine; the detected constituents are gaseous hydrogen chloride (CHl) and aluminum chlorhydrate compounds (Al.sub.2 Cl.sub.x .multidot.(OH).sub.6-x); and the detected characteristic is the opacity of the sampled gases. The invention includes a technique for adjusting the rate of halogen gas injection so as to approach the optimal rate. The invention also includes (1) a sensor for detecting the content of HCl and Al.sub.2 Cl.sub.x .multidot.(OH).sub.

Abstract: A torque coupling system includes an impeller that is connected to one end of an impeller shaft without the use of threads. The connection is made by cement and dowels. A drive system for the shaft includes a hollow coupling into which the other end of the shaft can be fitted. The shaft includes longitudinally extending slots formed at its end. The coupling includes spaced, longitudinally extending keys adapted to be fitted into the slots formed in the shaft. The drive system also includes a torque limiter that is connected intermediate the coupling and a drive motor. If the drive motor is an electric motor, the motor can be provided with automatic shut-down circuitry that is activated in the event of a current/torque overload. Visual and aural alarms are provided to alert the user that a shut-down has occurred.

Abstract: The filtration of molten ferrous metal is accomplished by providing a porous ceramic filter preferably comprising particles of alumina and partially stabilized zirconia that are spaced by interconnected cells to form circuitous and tortuous pathways throughout the ceramic body. The filter is a disc-like structure that can have different surface configuration such as corrugations or a waffle design. The filter can be flat-surfaced with an array of cylindrical openings or counterbored openings extending completely through the filter, or with openings extending partially into the filter from the upper and lower sides of the filter. Several relatively thin filters can be arranged in tandem, if desired.

Abstract: Fused cast refractory moldings having a random microstructure, which are near in size and configuration to the desired final shape, and process and apparatus used in their manufacture are described. The process includes rapid melting of the refractory material followed by controlled rapid cooling. Laminated composite fused cast refractories may be produced.

Abstract: A torque coupling system includes an impeller that is connected to one end of an impeller shaft without the use of threads. The connection is made by cement and dowels. A drive system for the shaft includes a hollow coupling into which the other end of the shaft can be fitted. The shaft includes longitudinally extending slots formed at its end. The coupling includes spaced, longitudinally extending keys adapted to be fitted into the slots formed in the shaft. The drive system also includes a torque limiter that is conected intermediate the coupling and a drive motor. If the drive motor is an electric motor, the motor can be provided with automatic shut-down circuitry that is activated in the event of a current/torque overload. Visual and aural alarms are provided to alert the user that a shut-down has occurred.

Abstract: A handleable, flexible, crack resistant intumescent sheet material for use in mounting fragile structures comprising a preformed intumescent layer, and a reinforcing layer bonded to the intumescent layer and having a tensile strength greater that the intumescent layer.