Back to results
US 4,965,031 AGranted
Continuous production of gypsum board
AssigneeThe Celotex Corporation
InventorAlan P. Conroy
Life of this patent
Estimating the term…
Abstract
A continuous process for the production of gypsum board of variable yet predictable density, wherein a fibrous from of stucco produced from gypsum crystals or fibers is combined with standard calcined gypsum and formed into the board. The density of the resultant board varies inversely with the content of fibrous stucco. The process yields lightweight boards suitable as standard wallboards and inorganic insulating boards.
Claims13
A continuous process for the formation of gypsum board which comprises:
- (a) forming an aqueous suspension of gypsum,
- (b) converting the gypsum in the suspension to a calcined product by reaction in a pressure vessel in the presence of saturated steam at a temperature greater than about 110.degree. C. for a period of time sufficient for conversion of all or a portion of the gypsum to fibrous calcium sulfate hemihydrate,
- (c) forming an aqueous suspension of the calcined product of step (b) with non-,fibrous calcium sulfate hemihydrate calcined at normal atmospheric pressure, and
- (d) forming the suspension of step (c) into a desired gypsum board shape, wherein the density of the gypsum board is inversely proportional to the amount of the fibrous calcium sulfate hemihydrate added in step (c).
1 more element
A continuous process for the formation of gypsum board which comprises:
- (a) converting gypsum fibers to a calcined product by calcination under normal atmospheric pressure and at a temperature in the range of from about 120.degree. to 190.degree. C. for a period of time sufficient for conversion of all or a portion of the gypsum fibers to fibrous calcium sulfate hemihydrate,
- (b) forming an aqueous suspension of the calcined product of step (a) with non-fibrous calcium sulfate hemihydrate calcined at normal atmospheric pressure, and
- (c) forming the suspension of step (b) into a desired gypsum board shape.
Dependencies are inferred from the claim text.