Abstract: Membrane-ready fibrous faced gypsum panels, methods, and apparatus are provided. The panels include a first fibrous mat having a first surface and a second surface, a second fibrous mat having a first surface and a second surface, a gypsum core in contact with the second surfaces of the first and second fibrous mats, and a material coating that covers the first surface of the first fibrous mat and forms a substantially smooth outer surface.

Abstract: A cementitious product with strengthened composite structure is provided. Energy-efficient methods for manufacturing such products are provided as well and include dewatering a partially-set cementitious product by applying vacuum, and also creating a concentration gradient across the product thickness. Systems for manufacturing such products are provided as well.

Abstract: Disclosed is a gypsum board forming device which provides improved slurry spread. The device includes a forming table with an arcuate or angled profile that promotes a uniform slurry spread. An arcuate or angled hinge plate can also be included to further promote the uniform distribution of slurry prior to an extrusion plate.

Abstract: The present invention provides an apparatus and a method for fractionating gypsum slurry which can surely control the density of the gypsum slurry fractionated from the mixer (fractionated slurry), which can restrict change of the flow rate of the fractionated slurry, and which can reduce the consumption of foam or foaming agent. The fractionation apparatus (30) fractionates the gypsum slurry from a mixer (4) for mixing calcined gypsum and water. The mixer has a hollow connector section (50), which allows the gypsum slurry to flow from a mixing area inside of the mixer into a chute section (5), and the chute section (5) discharging the inflow of gypsum slurry through its slurry discharge port onto a gypsum board liner paper. The fractionation apparatus has a slurry fractionation port (33) opening to the chute section or the hollow connector section, and causes a part of the gypsum slurry in the chute or hollow connector section to be delivered to a slurry delivery conduit (11,13,19).

Abstract: A method and apparatus for providing an evenly mixed additive enhanced gypsum slurry to a web. Calcined gypsum and water are inserted into a mixer through at least one inlet of the mixer. The contents are agitated to form a slurry. The slurry is passed from an outlet of the mixer into a conduit. An additive is introduced into the slurry along a length of the conduit to achieve a flow stream of a slurry/additive mixture. A cross section of the flow stream is expanded in the conduit while not changing direction of the flow stream and a direction of the flow stream is changed while not expanding the cross section of the flow stream and conduit, all prior to the flow steam exiting from an outlet of the conduit.

Abstract: The present invention relates to a system and associated method for the production of gypsum in manufacturing plant. More specifically, the invention relates to the production of alpha-type gypsum in a gypsum board manufacturing plant. The system yields increased efficiencies by capturing heat given off during processing steps and using that heat to reduce the energy needed for calcination. The invention finds particular application in the production alpha-type gypsum. The present invention is described in greater detail hereinafter in conjunction with the following specific embodiments.

Abstract: A gypsum board forming device (10) constitutes an apparatus of producing gypsum boards. A layered formation of a lower sheet (1), an upper sheet (2) and a gypsum slurry (6) passes through a forming gate (40). The forming device forms the formation into a plate-like configuration with use of upper and lower plates (20, 30). The upper plate (20) is constituted from a fixed substrate plate (21) and a movable plate (22), and the movable plate is in surface-to-surface contact with the upper sheet of the layered formation. A plurality of actuators (50) is supported by the substrate plate. Each of the actuators applies an upward or downward load (P) to the movable plate locally for a local deformation of the movable plate owing to a deflection thereof. A gate size (T) is locally changed by displacement of the movable plate relative to the substrate plate.

Abstract: A thermosetting solution composition composed of a biphenyltetracarboxylic acid compound containing a partial lower aliphatic alkyl ester of 2,3,3?,4?-biphenyltetracarboxylic acid and/or a partial lower aliphatic alkyl ester of 2,2?,3,3?-biphenyltetracarboxylic acid, an aromatic diamine compound in a molar amount larger than a molar amount of the biphenyltetracarboxylic acid compound, a partial lower aliphatic alkyl ester of 4-(2-phenylethynyl)phthalic acid compound in a molar amount as much as 1.8-2.2 times a molar amount corresponding to a difference between the molar amount of the aromatic diamine compound and the molar amount of the biphenyltetracarboxylic acid compound, and an organic solvent composed of a lower aliphatic alcohol is of value for manufacture of a prepreg.

Abstract: Disclosed is a gypsum board forming device which provides improved slurry spread. The device includes a forming table with an arcuate or angled profile that promotes a uniform slurry spread. An arcuate or angled hinge plate can also be included to further promote the uniform distribution of slurry prior to an extrusion plate. As a result of the improved slurry spread, gypsum board with increased strength and durability can be created.

Abstract: With a building board with a base body (10) with a porous surface and a paper web (14) applied onto the porous surface with intermediate arrangement of a curable binder (36), the paper web applied onto the base body is provided with a primer (34) that is suitable for covering binder that has penetrated through the paper web (10) and for promoting an adhesion between the surface of the paper web and a dyeing liquid (38), which can be applied to the surface of the paper web provided with the adhesion promoter by means of a programmable printing method, in particular an inkjet printing method.

Abstract: Disclosed is a gypsum board forming device which provides improved slurry spread. The device includes a forming table with an arcuate or angled profile that promotes a uniform slurry spread. An arcuate or angled hinge plate can also be included to further promote the uniform distribution of slurry prior to an extrusion plate. As a result of the improved slurry spread, gypsum board with increased strength and durability can be created.

Abstract: Disclosed are building board manufacturing techniques that minimize the build-up of slurry on associated forming equipment and also produce panels with enhanced physical properties. The methods involve applying a dissolvable film laminate to one or more fiber mats at the outset of the forming process. In the un-dissolved state, the film acts as a containment envelope for the gypsum slurry and any free floating glass fibers. During subsequent curing, the film is dissolved by vaporized water. In its dissolved state, the film is liquefied and coats the fibers of the underlying mat. This results in a building board with improved physical properties.

Abstract: The present invention relates to a system and associated method for the production of gypsum in manufacturing plant. More specifically, the invention relates to the production of alpha-type gypsum in a gypsum board manufacturing plant. The system yields increased efficiencies by capturing heat given off during processing steps and using that heat to reduce the energy needed for calcination. The invention finds particular application in the production alpha-type gypsum. The present invention is described in greater detail hereinafter in conjunction with the following specific embodiments.

Abstract: A method for coating a fire-resistant substance onto a carrier veil and products containing fire-resistant substances are provided. The method includes delivering a pliable carrier veil in a traveling web, drawing the carrier veil web through a reservoir defined by a nip of two rollers and containing the fire-resistant substance, where the carrier veil is coated with the fire-resistant substance. The method also includes controlling the amount of fire-resistant substance on the carrier veil web by setting a nip dimension between the two rollers, passing the carrier veil through the nip of the two rollers and providing the fire-resistant substance as a slurry suitable to coat the veil exiting the nip with a layer effective to provide a selected fire resistance. Heat is applied to the carrier veil sufficient to accelerate a curing reaction in the fire-resistant substance.

Abstract: A multilayer gypsum board forming device, and a gypsum additive delivery system in which additives are delivered to one or more layers of a multi layered gypsum board panels, including engineered polymers, includes at least one additive assembly connected in-line with a first gypsum delivery receptacle for providing an additive fluid feed into the stream of a first gypsum slurry being transported through said first gypsum delivery receptacle for homogenously adding an additive to the first gypsum slurry, and a second gypsum delivery receptacle transporting a second gypsum slurry, in fluid communication with the mixer providing the first gypsum slurry, having a different set of characteristics from those of the first gypsum slurry. At least one outer surface including a polymeric compound or wax emulsion additive entrained therein essentially encases the core gypsum within two facing layers.

Abstract: A head-box for depositing slurry upon a moving web including a main metering roll, a companion roll disposed in closely spaced relation to the metering roll and a vibrating gate which forms a nip between the metering roller and the gate. The nip is arranged to retain a supply of the slurry, and the rolls are driven so slurry retained in the nip progresses over an upper outer peripheral surface of the metering roll to be deposited upon the web. Also, preferably included is a doctor blade disposed in operational relationship to the metering roll for directing the slurry downwardly from the outer metering roll surface to a point above the surface of a carrier for a fiberglass layer upon which the slurry layer is deposited. The vibrating gate and doctor blade may be pivotally mounted to either side of the surfaces of the head-box.

Abstract: A gypsum board forming device (10) constitutes an apparatus of producing gypsum boards. A layered formation of a lower sheet (1), an upper sheet (2) and a gypsum slurry (6) passes through a forming gate (40). The forming device forms the formation into a plate-like configuration with use of upper and lower plates (20, 30). The upper plate (20) is constituted from a fixed substrate plate (21) and a movable plate (22), and the movable plate is in surface-to-surface contact with the upper sheet of the layered formation. A plurality of actuators (50) is supported by the substrate plate. Each of the actuators applies an upward or downward load (P) to the movable plate locally for a local deformation of the movable plate owing to a deflection thereof. A gate size (T) is locally changed by displacement of the movable plate relative to the substrate plate.

Abstract: Embodiments of the invention comprise a method of making a construction board (also known as wallboard) and a device for making same. The resulting construction board is formed by mixing of at least magnesium oxide, magnesium chloride, and a binding agent into a slurry, adding particulized solid material while funneling the slurry, and extruding the slurry comprising the particulized solid material.

Abstract: There is provided a lightweight plaster board having a cellular porous plaster core, excellent in adhesion to a covering base paper for a plaster board, free from dry-out in side edge parts of the plaster board, and with no disadvantage in workability for driving a nail into the plaster board. The plaster board includes a plaster core having a front surface, a back surface, and four side surfaces, and at least one covering base paper that covers the front surface, the back surface, and the at least two opposite side surfaces of the plaster core.

Abstract: A method for generating foam for gypsum product manufacturing includes injecting water through a conduit and injecting a foaming agent through the conduit to form a first solution comprising the water and the foaming agent. The method includes straining the first solution in the conduit and injecting air through the conduit to form a second solution comprising the water, the foaming agent and the air. The method also includes straining the second solution in the conduit to form foam and communicating the foam to a gypsum product manufacturing device.

Abstract: The technical problem of the invention is to improve the wetting of wood fibers with a binding agent. This technical problem is solved according to the present invention by a device for wetting wood fibers (10, 109) with a binding fluid, with a transport pipe (16, 105) for transporting the wood fibers (10, 109), with a fan (14, 106) for generating a transport air current, with a guide tube (17, 109) connected to the transport pipe (16, 105), with a fan (20, 110) for generating a conveying air current in the guide tube (17, 109), with means (27, 12) for supplying the binding fluid in the guide tube (17, 109). The invention also relates to a process for wetting wood fibers with a binding fluid.

Abstract: The present invention relates to a system and associated method for the production of gypsum in manufacturing plant. More specifically, the invention relates to the production of alpha-type gypsum in a gypsum board manufacturing plant. The system yields increased efficiencies by capturing heat given off during processing steps and using that heat to reduce the energy needed for calcination. The invention finds particular application in the production alpha-type gypsum. The present invention is described in greater detail hereinafter in conjunction with the following specific embodiments.

Abstract: A multilayer gypsum board forming device, and a gypsum additive delivery system in which additives are delivered to one or more layers of a multi layered gypsum board panels, including engineered polymers, includes at least one additive assembly connected in-line with a first gypsum delivery receptacle for providing an additive fluid feed into the stream of a first gypsum slurry being transported through said first gypsum delivery receptacle for homogenously adding an additive to the first gypsum slurry, and a second gypsum delivery receptacle transporting a second gypsum slurry, in fluid communication with the mixer providing the first gypsum slurry, having a different set of characteristics from those of the first gypsum slurry. At least one outer surface including a polymeric compound or wax emulsion additive entrained therein essentially encases the core gypsum within two facing layers.

Abstract: A cover stock supply system for continuously feeding cover stock to a wallboard production line includes: a plurality of cover stock cradles for receiving rolls of cover stock; a splicing table; a cover stock cutter disposed between the cover stock cradles and the splicing table. The cover stock cutter has a positioning loop around a cover stock feed path and a cutting cable attached to the positioning loop. Cutter is configured and adapted to rotatably deploy the cutting cable from the drawn position on a first side of the cover stock feed path to a re-set position on a second side of the cover stock feed path upon motion thereof around the cover stock feed path.

Abstract: A multiple layer fiber reinforced material and method of constructing the same including the provision of a first layer of a roll lofted glass material. Optional variants include the pre-application of plywood, OSB or fiber reinforced cement board materials prior to the first glass layer. A layer of a rolled fiber reinforced material is applied over the rolled glass material, with or without backing board material, and at least a second layer of the roll lofted glass material is applied over the rolled fiber reinforced material. A layer of a second rolled glass material is applied over the subsequent layer of the first glass material and a urethane resin syrup is intermixed with said layers of glass material and the fiber reinforced material. An application of heat and pressure results in the formation of the reinforced material. A flexural, closed cell foam material may also be applied to provide acoustical insulating properties to the multi-layer fiber material.

Abstract: A feed apparatus for use in depositing a slurry upon a moving web having a direction of travel includes a main metering roll, a companion roll disposed in closely spaced relation to the metering roll to form a nip therebetween. The nip is constructed and arranged to retain a supply of the slurry, and the rolls are driven so that slurry retained in the nip progresses over an upper outer peripheral surface of the metering roll to be deposited upon the web. Also preferably included is a thickness control roll disposed in operational relationship to the metering roll for controlling thickness of a layer of slurry drawn from the nip over the outer metering roll surface. Preferably, the metering roll, the companion roll and the thickness control roll are driven in the same direction.

Abstract: A gypsum board forming device having a gypsum forming station including two laterally disposed edger shoes, and at least one laterally disposed edger bar clamping element on the edger bar. In one embodiment a laterally extending forming plate extends over the top surface of the formed gypsum board, the forming plate including a plurality of micropore conduits through which pressurized water is supplied to provide a film of smoothing water over the top surface of the gypsum board. In another embodiment the edger shoes have a flapper mechanism for retaining unset slurry skimmed off the surface of the gypsum board by the edger bar.

Abstract: A system for making wallboard or backerboard sheets may include a mixer for mixing materials for making aerated concrete, at least one face layer supply, and a former downstream from the mixer. The former is for forming core material having opposing first and second major surfaces and comprising aerated concrete, and for securing at least one face layer from the at least one face layer supply onto at least one of the first and second major surfaces of the core material. The system may also include a cutter downstream from the former for cutting the core material and at least one face layer secured thereto into a plurality of wallboard or backerboard sheets. The provision of aerated concrete for the core provides many key advantages over conventional gypsum wallboard sheets, and/or conventional backerboard sheets, such as gypsum greenboard or cementitious backerboard, for example.

Abstract: A process for manufacturing plasterboard and a plasterboard manufacturing unit are provided, the process including feeding hydratable calcium sulphate and water into a first mixer (2) and into a second mixer (3); feeding in a facing (5); preparing a first gypsum slurry in the first mixer (2); preparing a second gypsum slurry in the second mixer (3); applying the first slurry onto the facing and forming a crude surface layer; applying the second slurry onto the crude surface layer and forming a crude core layer with a density lower than that of the crude surface layer; forming a plasterboard; hydrating and drying the board. This process allows the formation of the different layers of gypsum to be controlled independently.

Abstract: An improved method and apparatus for imparting a smooth surface to a gypsum fiber panels. The method involves imparting energy to the surface of the slurry as the slurry is dewatered just prior to rehydration. The apparatus used to impart the energy is an air lance including an air source such as a blower, a distribution manifold and a plurality of nozzles to direct the flow of air at the surface of the slurry. In operation, the air lance directs a flow of air against the surface of the slurry. The flow disrupts the slurry to a fraction of its total depth, thus dispersing clumps or flocs of crystals in the depth that would give the surface of the finished panel a rough surface if they were allowed to remain.

Abstract: A method for manufacturing sheets of plasterboard includes (i) forming the sheet; (ii) setting it by hydration until a hydrated product with a content of below 80% is obtained; (iii) continuing hydration in at least one revolving barrel; and (iv) drying. The revolving barrel includes a number of branches.

Abstract: A method for manufacturing sheets of plasterboard includes forming the sheet; setting the sheet with hydration; and drying while the sheet is being rotated. A barrel is used for drying.

Abstract: The present invention comprises apparatus for the manufacture improved structural panel with synthetic ingredients, such as vermiculite and fibers. The improved structural panel achieves enhanced lateral and surface integrity by the use of fibers within the core of the structural panel and adhesives and smooth materials (such as foil) as a surface coating. The apparatus is particularly suited for manufacture of the structural panel at low cost and high efficiency.

Abstract: A system and method for monitoring the conditions in a gas plasma processing system while varying or modulating the RF power supplied to the system, so that resulting signals of the electrical circuits of the system provide information regarding operational parameters of the system or the state of a process. Significant improvements in sensitivity and accuracy over conventional techniques are thereby achieved. In addition, the plasma processing system can be thoroughly tested and characterized before delivery, to allow more accurate monitoring of and greater control over a process, thereby improving quality control/assurance of substrates being produced by the system. The information obtained by the modulation technique can be displayed on a monitor screen, in order to allow an operator to accurately monitor the system/process and diagnose any problems with the system/process.

Abstract: A retainer is used with an apparatus for polishing a substrate. The substrate has upper and lower surfaces and a lateral, substantially circular, perimeter. The apparatus has a polishing pad with an upper polishing surface for contacting and polishing the lower face of the substrate. The retainer has an inward facing retaining face for engaging and retaining the substrate against lateral movement during polishing of the substrate. The retaining face engages a substrate perimeter at more than substantially a single discrete circumferential location along the perimeter.

Abstract: A cementitious panel comprising a cementitious core which is fabric-reinforced at the surface thereof and whose longitudinal edges are reinforced by a network of fibers. A panel may be obtained wherein the surface edge reinforcement layers are relatively strong and hard such that a nail or screw may be driven through the edge of panel without pre-drilling and without breaking, even when nailed or screwed almost at the very limit of the edge of the panel. Such a panel may provide a long lasting substrate for humid or wet areas such as shower rooms and bath rooms.

Abstract: Heat sink and electrically non-conducting thermal interface having shielding to attenuate electromagnetic interference. The interface comprises a generally planar substrate having first and second outwardly facing surfaces. The substrate is formed from a material, preferably a polymer, that is both thermally conductive and has a high dielectric strength. Formed upon the outwardly facing surfaces are layers of a thermally conductive compound for facilitating heat transfer. The invention further comprises an improved heat sink comprising a baseplate coupled with a folded-fin assembly, the latter being compressively bonded thereto via a pressure clip and pressure spreader assembly. The base plate is attachable to a heat-dissipating component, and may optionally include a ground contact connection for use with components that are not already grounded.

Abstract: Provided are a process and an apparatus for producing gypsum boards, both of which feature minimized occurrence of defective products and especially excellent continuous productivity and superb efficiency. Making use of the facts that lining paper sheets for gypsum boards are insulators and a gypsum slurry held between the lining paper sheets is a good electrical conductor, a detection of an electric current flowing between an upper forming unit and a lower forming unit or a like method makes it possible to promptly detect any localized tearing which may occur in the overlay paper and/or underlay paper due to an undesired object or the like mixed in during continuous production of gypsum boards and moreover, to readily remove the undesired object or the like as a cause for the tearing without stopping the production of gypsum boards while preventing the localized tearing from spreading over the entire width of the paper.

Abstract: An improved method and apparatus for imparting a smooth surface to a gypsum fiber panels. The method involves imparting energy to the surface of the slurry as the slurry is dewatered just prior to rehydration. The apparatus used to impart the energy is an air lance including an air source such as a blower, a distribution manifold and a plurality of nozzles to direct the flow of air at the surface of the slurry. In operation, the air lance directs a flow of air against the surface of the slurry. The flow disrupts the slurry to a fraction of its total depth, thus dispersing clumps or flocs of crystals in the depth that would give the surface of the finished panel a rough surface if they were allowed to remain.

Abstract: An apparatus for use in the manufacture of plasterboard (100) having at least a first side faced with a facing liner (2), a cementitious core (1) and an opposite side faced with a backing liner (4), includes a support surface (3) with a required surface finish to support the facing liner (2) and the first side of the plasterboard, pressurized fluid supply means to supply a fluid at above atmospheric pressure and at least one fluid directing means (5) to direct the pressurized fluid from the pressurized fluid supply means onto the opposite side of the plasterboard after the cementitious core (1) has partially set but before it has set to a knife set point. The pressurized fluid exerts a substantially uniform pressure on the backing liner (4) and the opposite side of the plasterboard, thereby smoothing the facing liner (2) and the first side of said plasterboard by urging them toward the support surface (3).

Abstract: A system for making wallboard or backerboard sheets may include a mixer for mixing materials for making aerated concrete, at least one face layer supply, and a former downstream from the mixer. The former is for forming core material having opposing first and second major surfaces and comprising aerated concrete, and for securing at least one face layer from the at least one face layer supply onto at least one of the first and second major surfaces of the core material. The system may also include a cutter downstream from the former for cutting the core material and at least one face layer secured thereto into a plurality of wallboard or backerboard sheets. The provision of aerated concrete for the core provides many key advantages over conventional gypsum wallboard sheets, and/or conventional backerboard sheets, such as gypsum greenboard or cementitious backerboard, for example.

Abstract: A system for making wallboard or backerboard sheets may include a mixer for mixing materials for making aerated concrete, at least one face layer supply, and a former downstream from the mixer for forming core material having opposing first and second major surfaces and comprising aerated concrete. The former is preferably also for securing at least one face layer from the at least one face layer supply onto at least one of the first and second major surfaces of the core material. The former may include a mold downstream from the mixer for receiving the materials for making aerated concrete therein and allowing the materials to rise and stiffen into a body, an autoclave downstream from the mold for curing the body, and a saw blade downstream from the autoclave for sawing the body into sheets of core material. A magnetic field generator is provided adjacent the saw blade for causing the saw blade to be substantially flat to saw substantially flat sheets of core material from the body.

Abstract: A system and method for monitoring the conditions in a gas plasma processing system while varying or modulating the RF power supplied to the system, so that resulting signals of the electrical circuits of the system provide information regarding operational parameters of the system or the state of a process. Significant improvements in sensitivity and accuracy over conventional techniques are thereby achieved. In addition, the plasma processing system can be thoroughly tested and characterized before delivery, to allow more accurate monitoring of and greater control over a process, thereby improving quality control/assurance of substrates being produced by the system. The information obtained by the modulation technique can be displayed on a monitor screen, in order to allow an operator to accurately monitor the system/process and diagnose any problems with the system/process.

Abstract: A novel wallboard composition is disclosed comprising a unique combination of synthetic binders selected for their ability to establish a strengthened permanent bond in the final dry state for use in a wallboard composition comprising primarily gypsum, and in a wallboard composition comprising an expanded mineral such as Perlite which largely reduces the amount of gypsum over current gypsum wallboard formulations, thus reducing the weight while maintaining the strength of the wallboard structure. In a preferred embodiment, the lightweight, strengthened wallboard of the present invention also comprises an optional covering veneer that is applied to the top ply of the face paper to provide increased strength, moisture resistance, and fire retardency, and the back paper top ply is treated to provide increased flexural strength.

Abstract: A novel wallboard composition is disclosed comprising a unique combination of synthetic binders selected for their ability to establish a strengthened permanent bond in the final dry state for use in a wallboard composition comprising primarily gypsum, and in a wallboard composition comprising an expanded mineral such as Perlite which largely reduces the amount of gypsum over current gypsum wallboard formulations, thus reducing the weight while maintaining the strength of the wallboard structure. In a preferred embodiment, the lightweight, strengthened wallboard of the present invention also comprises an optional covering veneer that is applied to the top ply of the face paper to provide increased strength, moisture resistance, and fire retardency, and the back paper top ply is treated to provide increased flexural strength.

Abstract: A system includes a saw comprising at least one saw blade for sawing at least one body of aerated concrete into sheets of core material having opposing major surfaces, at least one face layer supply, and a conveyor for advancing the sheets of core material along a path of travel as at least one face layer is secured thereto from the at least one face layer supply. The system may further include a shuttle for repetitively advancing the at least one body of aerated concrete past the at least one saw blade to saw successive sheets of core material. The shuttle, in turn, may comprise a car for carrying the at least one body of aerated concrete, a track for guiding the car, and at least one actuator for moving the car along the track. The saw blade may extends in a substantially horizontal direction. Accordingly, the saw may further comprise a vertical indexer for vertically indexing the at least one saw blade to saw successive sheets of core material.

Abstract: A system for making wallboard or backerboard sheets may include a former for forming core material having opposing first and second major surfaces and comprising aerated concrete, and for securing at least one face layer from at least one face layer supply onto at least one of the first and second major surfaces of the core material. The former may include a saw blade for sawing bodies of cured aerated concrete into sheets of core material, a lower conveyor for advancing a series of bodies past the saw blade, and an upper conveyor for conveying a remaining portion of a body downstream from the saw blade back to a position upstream from the saw blade. Accordingly, the former provides for the efficient processing of relatively large cured bodies of aerated concrete to be formed into wallboard or backerboard sheets.

Abstract: A novel construction board composition is disclosed comprising a unique combination of synthetic binders selected for their ability to establish a strengthened permanent bond in the final dry state for use in a construction board composition comprising primarily gypsum, and in a construction board composition comprising an expanded mineral such as Perlite which largely reduces the amount of gypsum over current gypsum construction board formulations, thus reducing the weight while maintaining the strength of the construction board structure. In a preferred embodiment, the lightweight, strengthened gypsum construction board of the present invention also comprises an optional covering veneer that is applied to provide increased strength, moisture resistance, and fire retardency, and the back paper top ply is treated to provide increased flexural strength.

Abstract: Methods and apparatus are disclosed for producing gypsum board having at least one facing sheet, a core of cementitious material such as low density gypsum, and an intermediate layer of bond promoting material, such as higher density gypsum located therebetween. The apparatus includes a forming table having a transverse gap. The facing sheet travels along the forming table over the gap. A spreader roller has an outer surface extending partially into the gap to depress the facing sheet. The bond promoting material is deposited on the facing sheet upstream of the spreader roller and the spreader roller outer surface rotates in the same direction as the facing sheet to coat the facing sheet with the bond promoting material. The core layer material is deposited on the facing sheet downstream of the spreader roller on top of the bond promoting coating.

Abstract: A gypsum/fiber board having improved impact resistance is produced by mixing predetermined amounts of fibers, calcined gypsum and water to form a mixture of wetted, loose fibers; laying out a reinforcing mesh over the upper surface of a forming belt; depositing said mixture on said mesh to form a layer of said mixture, said; and compressing said mesh together with said layer of mixture to embed said mesh in the lower surface of said layer to form a board composed of bonded fibers and gypsum with said mesh embedded in the surface thereof.