Abstract: A method and system for calcining gypsum to recover gypsum in a form consisting essentially of calcium sulfate anhydrite is disclosed. The method includes the steps of feeding the ground gypsum material into a first kettle and heating the ground gypsum in the first kettle to the first predetermined temperature. The first predetermined temperature is preferably below 400.degree. F. so that the gypsum will still contain a sufficient amount of chemically-combined water so that it will self-fluidize by release of water vapor so that it will flow through the apparatus. The ground gypsum is then overflowed through at least one subsequent stage and heated to a final predetermined temperature to produce an anhydrite product. To produce insoluble calcium anhydrite or dead burn material, the final predetermined temperature is greater than 900.degree. F. and preferably within the range of about 900.degree. F.-1300.degree. F.

Abstract: A method and system for calcining gypsum to recover gypsum in a form consisting essentially of calcium sulfate anhydrite is disclosed. The method includes the steps of feeding the ground gypsum material into a first kettle and heating the ground gypsum in the first kettle to the first predetermined temperature. The first predetermined temperature is preferably below 400.degree. F. so that the gypsum will still contain a sufficient amount of chemically-combined water so that it will self-fluidize by release of water vapor so that it will flow through the apparatus. The ground gypsum is then overflowed through at least one subsequent stage and heated to a final predetermined temperature to produce an anhydrite product. To produce insoluble calcium anhydrite or dead burn material, the final predetermined temperature is greater than 900.degree. F. and preferably within the range of about 900.degree. F.-1300.degree. F.

Abstract: This invention is a process and foaming system for producing foamed gypsum board which permits the production and control of large foam voids in the gypsum core by adjusting the ratio of a first foaming agent and a second foaming agent. My process includes the steps of preforming a first foaming agent which forms stable foam voids in a gypsum slurry and independently preforming a second foaming agent which forms unstable foam voids in a gypsum slurry. Independently, blending the two different foaming agents is the key to controlling void size. A greater amount of the second foaming agent and a lesser amount of the first foaming agent is preferred.

Abstract: Apparatus and method for belt transfer printing of nonflat surfaces of porous articles wherein the printing of the article by a first region of the belt is carried out substantially simultaneously with the inking of a second region of the belt. In a preferred embodiment, the apparatus comprises an endless belt with a screen printing device disposed along a first run of the belt and a vacuum workpiece support box disposed along a second run of the belt with an opposed sealing frame. A workpiece is loaded in the vacuum box, a vacuum is created through the workpiece to draw a pattern carrying region into printing contact with the workpiece surface while another pattern is being inked onto a second region of the belt. The workpiece is replaced with a second workpiece and the second region of the belt is advanced into registration with the second workpiece.

Abstract: An intersection spacer is disclosed for use in a subceiling structure of a grid of open-ended runner beams and intersecting open-ended cross beams, the intersection spacer being generally square in horizontal cross section with inverted vertical corner edges forming four outwardly directed protrusions adapted to engage within the beam ends. A top plate on the spacer bears the weight of the ceiling. A bottom cap on the spacer carries a decorative panel. The spacer may be made of two identical mating halves. A method of assembling a subceiling with such intersection spacers is also disclosed.

Abstract: Hang-on furniture supporting studs standing independently at the intersection of wallboard partitions are tied together by an intersection stud for proper orientation and stabilization.

Abstract: A setting accelerator for calcined gypsum plaster and a process for its preparation are disclosed. The accelerator comprises finely ground calcium sulfate dihydrate having composite coatings on the particles of firstly a calcination inhibiting material such as sugar and secondly a coating of aluminum sulfate hydrate. The accelerator is particularly useful in the formation of gypsum wallboard.

Abstract: Expanded perlite coated with an amino-functional siloxane and a silicone wetting agent, and a joint compound incorporating same, which, when applied to gypsum wallboard, has improved bonding properties and greater uniformity in paint gloss appearance between the surface of the joint compound and the surface of the wallboard.

Abstract: A structure comprising movable doors for use in tub enclosures or shower stalls, each door having a frame and a panel mounted in the frame, and adjustment apparatus for raising or lowering one side of the door to compensate for out-of-plumb wall conditions, the adjustment apparatus comprising a pair of complementary adjustment members slidably inter-engaged along edges oblique with respect to the upper edge of the doorframe, a lower adjustment member being affixed to the doorframe and an upper adjustment member having a hanger assembly integral therewith provided with rollers or glides adapted to move on a track provided on a supporting doorframe or header.

Abstract: Expanded perlite is produced while simultaneously or substantially simultaneously coating the expanded perlite with an hydrophobic coating material by passing the expanded perlite and heated expander exhaust gases from the expansion chamber through a cooling and coating chamber provided with spray nozzles to provide a stream of atomized coating material onto the expanded perlite, while upstream thereof an air intake and temperature sensor are situated to control the air flow and temperature in the cooling and coating chamber so as to provide proper curing temperatures for the coating material upon the expanded perlite before it is separated from the exhaust gases.

Abstract: Mineral filler materials are provided with improved hydrophobic coatings by pressure coating of porous minerals using steam as a carrier for the coating material. Thereby more complete sealing of fissures and cracks in the porous filler materials' surface is provided, resulting in very water-resistant coated particles useful in filling polymeric substrates such as paints, plastics and joint compounds.