Gypsum board manufacture with co-rotating spreader roller

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. The speed of the spreader roller, the tension in the facing sheet, and the viscosity of the bond promoting material are varied within predetermined limits to adjust the thickness of the bond promoting material layer and prevent build up of said material on the spreader roller.

Dependencies are inferred from the claim text.