Disclosed are a composite gypsum board and a method of preparing composite gypsum board. The board contains a set gypsum core sandwiched between two cover sheets. The core is formed from a slurry containing stucco, water, and optional ingredients such as foaming agent, accelerator, retarder, polyphosphate, starch, and dispersant, and core intumescent material. The board also contains at least one skim coat and/or hard edges. A face skim coat layer can be included on one side of the core, facing a face cover sheet. A back skim coat layer can be included on the other side of the core, facing a back cover sheet. Hard edges are known in the art and can be formed, e.g., continuously from a stucco slurry for forming the face and/or back skim coats. Preferably, the back skim coat layer and/or the hard edges are formed from a slurry containing stucco, water, skim coat or edge intumescent material (which have the same desired characteristics), and other optional additives as desired. The skim coat or edge intumescent material can be composed of the same material as the core intumescent material, if desired, but the skim coat and/or edge intumescent material is present in a higher relative concentration in its respective slurry than the amount of core intumescent material in the core slurry. Examples of suitable intumescent materials include expandable vermiculite (e.g., No. 4 or No. 5 according to the US naming system, or combinations thereof), expandable graphite, perlite, or any combination thereof.

Techniques of forming a foamed insulation material from gypsum waste are disclosed herein. One example technique includes mechanically comminuting the gypsum waste from an original size into particles of gypsum at a target size smaller than the original size and mixing the particles of the gypsum with a binder to form a mixture of particles and binder. The binder is configured to bind the particles of gypsum upon hydration. The example technique can further include performing air entrainment on the mixture until a foam is formed from the mixture having the particles of gypsum and binder. The foam has water that causes the binder to bind the particles of gypsum. The example technique can then include removing moisture from the mixture with the formed foam to form a foamed insulation material from the particles of gypsum.

A system for controlling a line speed of a conveyor belt of a conveyor system during product changeovers in a wallboard production line includes a computer processor, a calculation module for calculating a predetermined mass rate of a supply of ingredients transported on the conveyor belt and deposited into a mixer during a product changeover period, and a speed adjustment module for adjusting the line speed of the conveyor belt, using the processor, based on at least one of the predetermined mass rate and the line speed of the conveyor belt for reducing an overshoot during said product changeover period.

Methods of making gypsum panels, and the panels and systems of panels prepared by such methods are provide. The methods include forming a first gypsum slurry by combining stucco, water, and a siliconate and setting the first gypsum slurry to form at least part of a core of the gypsum panel.

A production line and process including a moving carrier web for transporting the panel, and a device for controlling thickness of a formed, but not yet set, fiber reinforced cementitious panel slurry on the web. The thickness control device may include an angled rigid plate for contacting a downstream end of the angled plate with the slurry on the moving carrier web and a mounting stand for mounting the angled rigid. The thickness control device may include a flat horizontal plate at a fixed height over the moving carrier for contacting the entire lower surface of the horizontal plate with a facer on the slurry on the moving carrier web. Or, the thickness control device may include the angled plate and include the horizontal plate that contacts the facer.

A gypsum panel includes a gypsum core containing a termiticide with poor water solubility, wherein the gypsum core has a first end region, a center region, and a second end region having an equal thickness and extending along a thickness direction from one surface side to another surface side, the termiticide is contained in each of the first end region, the center region, and the second end region, and a content of the termiticide in the center region is lower than a content of the termiticide in the first end region and in the second end region.

A slurry feed apparatus for depositing a slurry upon a moving forming web having a direction of travel, including: a headbox mounted transverse to the direction of travel of the moving web, having a back wall, sidewalls, a concave transverse front wall, an open top, and an open bottom for directing slurry onto the forming web; a moveable dam releasably attached to the back wall, a seal attached to a bottom wall of the dam; and a headbox support system extending from opposed the sidewalls. Also disclosed is a continuous process for depositing a uniform layer of a cementitious slurry containing reinforcing fibers from the headbox onto a traveling web.

There is provided an inspection apparatus for inspecting a plate-shaped inspection target being conveyed. The inspection apparatus includes a light source configured to emit a linear light. beam extending along the thickness direction of the inspection target to irradiate a side surface at a lateral end of the inspection target in a width direction orthogonal to a conveying direction of the inspection target, an imager configured to capture the light beam emitted from the light source and irradiating the side surface at the lateral end of the inspection target, an imager driving device configured to move the imager, and an imager controller configured to control the position of the imager. The imager controller is configured to control the position of the imager according to the position of the lateral end of the inspection target.

A gypsum slurry mixer output canister is provided, including a canister housing having an upper end, an opposite lower end and defining a canister interior, a cover secured to the upper end, a slurry inlet in operational relationship to the upper end, a spiral block associated with the upper end, and having a helical flow surface depending into the interior. A flow distributor is secured to the lower end and is in fluid communication with the interior, and a slurry outlet is defined by the lower canister housing end.

The invention relates to a conveyor line (1) for the continuous production of drywall boards as well as a slurry distributing device (22) which is used in this conveyor line (1). The distributing device is used for the uniform and low-speed flow distribution of slurries (20).