United States Gypsum Company

Richard James Haszel

James Wittbold

Alfred C Li

Chris C Lee

David R Blackburn

Brent E Groza

Bruce Lynn Petersen

James R Wittbold

A gypsum slurry is provided that includes calcium sulfate hemihydrate; water; a dispersant component comprising at least one of the following a comb-branched polymer with polyether side chains, naphthalene sulfonate-formaldehyde condensate or melamine sulfonate-formaldehyde condensate; a foaming agent; and a polycondensation component with three polycondensation repeating units. Also provided is a method for making a gypsum slurry with a foaming agent in which the ratio between the dispersant component and the polycondensation component is adjusted to control for the size of foam bubbles in the gypsum slurry. Gypsum products made from the gypsum slurry are provided and methods for making the products are provided as well.

Additives in gypsum slurries and adjusting their proportions

A panel is provided that includes stucco, water and a dispersant component having dispersing properties and comprising a comb-branched polymer with polyether side chains, naphthalene sulfonate-formaldehyde condensate or melamine sulfonate-formaldehyde condensate. A polycondensation component is also included in the slurry that includes three repeating units. A method of making the gypsum panel includes combining stucco, water and a first dosage of a first dispersant to form a slurry, the first. A second dosage of a second dispersant is added to the slurry. Properties of the gypsum slurry are tested and it is formed into a product. The product sets and properties of the product are identified. The first dosage or the second dosage is changed based on the properties of the slurry or product.

Additives in gypsum panels and adjusting their proportions

A method for providing a smoothly mixed slurry to a web is provided which includes inserting calcined gypsum and water into a mixer (), agitating the contents of the mixer () to form an aqueous dispersion of the calcined gysum, and passing the agitated contents from an outlet () of the mixer () into a slurry dispensing apparatus () including a flexible, resilient conduit (). Additionally, the method includes the step of creating a back-pressure on the mixture in the slurry dispensing apparatus by constricting the conduit (). The constricting of the conduit () is effected by a constrictor valve () located on the conduit ().

Slurry mixer constrictor valve

An apparatus and method for controlling the flow of a slurry is provided which includes using a constrictor valve on a mixing and dispensing apparatus. The constrictor valve includes a first guide plate and a second guide plate that are spaced a distance apart along the length of the conduit. Extending between the two guide plates, a plurality of elongate members have first and second ends engaged on the first and second guide plates. Upon rotation of at least one of the first and second guide plates, the elongate members are configured to impart pressure on, and constrict the conduit.

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Mundelein, IL, United States of America

Richard James Haszel