Abstract: A processor for particulate material including a cylindrical vortex chamber, a main inlet duct communicating with the chamber at one otherwise closed end for supplying particulate substance in a direction substantially tangential to the interior surface of the vortex chamber and preferably inclined toward the other end, with the cylindrical portion of the vortex chamber being provided with a number of further inlets for the supply of active medium consisting essentially of slits in the vessel wall, with adjacent portions of vessel wall being bent out of the cylindrical curved plane, forming, by such bent portions, inlets which will direct the active medium into the vortex chamber in a tangential and inclined direction similar to the preferred direction of the inlet duct. A particulate material outlet and active medium outlet are also provided.

Abstract: A joint compound, having crack resistance substantially equal to joint compounds containing mica, wherein the mica has been replaced by low length to width ratio gypsum crystals formed by the hydration of calcium sulfate to calcium sulfate dihydrate, particularly crystals formed in the presence of citric acid.

Abstract: A large T-square having retractable pins for temporary attachment of the T-square to the face of a product such as a gypsum wallboard.

Abstract: A method of making gypsum wallboard in which a portion of the conventional foamed gypsum slurry for forming the wallboard core is fed through a relatively low speed agitator wherein a defoaming agent is thoroughly admixed therewith, and this portion of the slurry is then disposed along the edge portion of the wallboard being formed, whereby a hard-edge wallboard is produced using less energy than used with prior methods for making a hard-edge wallboard.

Abstract: An elongate sheet metal stud having a cross-section including a central web and two oppositely directed flanges on the two sides of the stud extending perpendicularly from the web, and having the ends of the flanges detached from the web and free to straddle the floor and ceiling tracks, permits ease of stacking a plurality of studs and provides firmness while screwing board to the flanges.

Abstract: A broad knife for applying joint compound to one side of an inside corner, having compound previously applied to the other side, the blade of which knife has a small protuberance adjacent the side edge of the blade, on the top face, adapted to ride along the surface of the previously applied joint compound on the other corner side.

Abstract: A thin, circular mixing apparatus for receiving from separate sources (1) dry calcined gypsum powder and (2) the liquid ingredients of the core of a gypsum wallboard, with the liquids being fed to a small diameter radially inward centrifugal pump portion, the dry ingredients being fed to a medium diameter circular portion into which the centrifugal pump elements continually force the liquids in an outwardly spiralling path and having a radially outermost circular portion into which the mixture is further forced in a continued outwardly spiralling path and out from which the mixture is discharged, between rotating radially outwardly projecting teeth.

Abstract: Formed sheet metal elongate studs and furring channels with two separate sections bonded together, each section having means for attachment to a wall base or a wall facing material. The sections are bonded together with a heat-sensitive material, preferably a hot-melt adhesive, which melts and separates the sections in a fire, and also tends to reduce thermal conductivity through the stud under conditions that do not melt the adhesive.

Abstract: The air flow in one zone of a gypsum wallboard dryer involves removal of the air from the wallboard drying section at one end of the elongate wallboard drying section, followed by directing a major portion of this air through fans to accelerate the air flow, next heating the air in an elongate plenum, through which the air passes, by directing high intensity flame angularly into the air flow from the periphery of the elongate section, thus creating agitation within the air flow to create uniformity of temperature therethroughout prior to directing the heated, thoroughly mixed air back into the wallboard drying section, at an end of the section opposite to the end from which it was originally removed.

Abstract: Drying oils are used to improve strength and durability characteristics of gypsum wallboard paper with many unexpected additional advantages. Applied before board manufacture, critical porosity characteristics are left uninterrupted. Applied after board manufacture, shear strengths are obtained beyond expectations.

Abstract: Continuous calcination of gypsum is provided by uniformly feeding uncalcined gypsum into the calcining batch in a kettle to a location below the surface but above the uppermost agitator, and allowing calcined gypsum to be discharged from the kettle through a discharge outlet in the wall of the kettle at the top surface of the calcining gypsum.

Abstract: A window having the highly desirable appearance of being a plurality of panes each adjoined to adjacent panes by cross-bars having the triangular cross-section, on each face of the window, which is typical of the cross-bars of wooden divided sash, which appearance is created by the printing of a single design on only one side of the window with only one color, and incorporating unpainted areas to produce the illusion of three-dimensional depth of a triangular cross-section.

Abstract: An exterior wall or a roof-ceiling structure having, on the interior side, a wallboard with a front face which forms the interior wall or ceiling surface and a back face, which is adhered to wall framing members. The back face has a paper-foil laminate which is adhered to the basic board back side, with the foil side of the laminate adhered directly to the basic board back side. The paper side of the laminate is adhered directly to the wall framing members.

Abstract: A wall of gypsum wallboard adhered indirectly to studs, in which the studs have an intermediate material, which has a preplanned degree of weakness, affixed to the stud face, and to which material the wallboard is adhered, to hold it relative to the studs, whereby on removal of the wallboard, the relatively dried bead of adhesive is easily removed from the wallboard back side and/or the stud face, leaving both in condition for reuse with new adhesive, in constructing a new wall.

Abstract: Plastic sheet material, laminated to the front face and side edges of wallboard, having excess sheet width at each side edge, is uniformly and rapidly trimmed to a neat skived edge which becomes firmly adhered to the wallboard edge, by abrading through the sheet material with a rotary abrader such as a nylon brush.

Abstract: Intersecting hollow flat strips are adjoined by a concealed semi-rigid thin clip, having the configuration of a wide plus sign. The flat strips have half thickness cutouts to permit interlocking engagement of two intersecting strips, with the thin clip inserted within the cutouts. The thin clips have dimensions and configurations which permit assembly or disassembly with slight force but prevent unintentional disassembly.

Abstract: A temporary holding of wallboard against studs with adhesive therebetween, while the adhesive sets, involving an elongate semirigid rod removably affixed at one end to the stud, the other end projecting out from between the edges of two adjacent wallboards, and a retainer plate engaging the flexible rod and pressing the wallboards against the stud, the engagement of the plate with the rod being such that the rod prevents the plate from moving away from the wallboard until removal is desired.

Abstract: A predecorated printed paper on the gypsum wallboard with a clear washable coating over the printed paper, and having a thin coating of polyethylene emulsion on the back paper which overcomes the tendency of the coated predecorated paper to stick to the back paper of an adjacent board when the boards are piled in stacks for storage and shipment.

Abstract: Lightweight gypsum wallboard produced by continuously combining a small amount of surface active agent with a liquid stream which stream is made up of substantially all of the liquids to be used in the manufacture of a continuous web of gypsum wallboard, subjecting this mixture to an intense agitation with vaned saw tooth-like rotary blades in a foam generator while adding a controlled quantity of air thereto, forming a uniformly dispersed foam of very small bubbles from the liquid by completely generating all of the surface active agent therein to form this foam, and mixing this foamed liquid with finely ground dry calcined gypsum in a suitable mixing device to form a foamed settable gypsum slurry, disposing the slurry between paper cover sheets, and forming a continuous web of gypsum wallboard.

Abstract: A continuous calciner, particularly advantageous in converting gypsum to plaster, with two coaxial cylindrical walls, provides for heating air within the inner cylinder and then directing the air, for conveying and heating fine particles, along a spiral path, between the walls of the two coaxial cylinders, extending from one end of the calciner to an exit at the second end.