Patent ID: 7897079

Claim:
A method of producing a gypsum/fiber board comprising the steps of: mixing ground gypsum and host particles of a fibrous reinforcing material and sufficient liquid comprising water to make a slurry having fibrous solids and at least 60% liquid by weight; calcining the gypsum in the presence of the host particles and the water, by heating the slurry under pressure, to form a slurry mixture comprising water and calcium sulfate alpha hemihydrate crystals; feeding the slurry mixture through a headbox to a panel forming area over the upper surface of a flat porous forming fabric of a moving conveyor; providing a transverse member over a portion of the forming fabric, wherein a downstream portion of the transverse member is under a downstream portion of the headbox or downstream of the headbox; passing a layer consisting essentially of reinforcing mesh under the headbox, over the transverse member, and into a forming pond on the forming fabric to embed the reinforcing mesh in the slurry mixture in the forming pond, wherein the transverse member extends transverse to a direction of movement of the mesh, and wherein the transverse member comprises a sheet located over a portion of the forming fabric, the sheet having an upstream portion, a downstream portion, and a middle portion between the upstream portion and the downstream portion, wherein the upstream portion of the sheet is upstream of an upstream lip of the head box, wherein the middle portion of the sheet is under the headbox, wherein the reinforcing mesh passes between the sheet and the headbox and into the forming pond to embed the reinforcing mesh in the slurry mixture in the forming pond, wherein the sheet has transverse bends to form an inverted S-shaped curve, with the lowest elevation of the sheet where a bottom of the sheet contacts the forming fabric under the headbox and the highest elevation of the sheet at the infeed of the mesh upstream of the headbox, and an intermediate elevation of the sheet at the downstream end of the sheet, removing water from the slurry mixture to form a panel mat with the mesh embedded in the panel mat; pressing the panel mat having the embedded mesh; rehydrating the calcined gypsum of the pressed panel mat to form a board comprising bonded host particles and gypsum with the mesh embedded in the board; and drying the board to provide a finished board with the mesh embedded in the finished board.