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AssigneeUnited States Gypsum Company
InventorsSteven Burdett Johnson, Charles Allen Whittington, Lyle Dee Fullmer
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This invention provides a method and apparatus for mixing calcined gypsum. The invention comprises a mixer which employs high pressure water to eliminate or substantially reduce the formation of lumps of gypsum inside the mixer which cause paper breaks when the calcined gypsum slurry containing the lumps is used to form the gypsum core in a gypsum wallboard product. High pressure water jets direct a spray of high pressure water at the surfaces within the mixer where the lumps of gypsum are formed. The method of this invention utilizes the high pressure water as part of the metered water that is continuously fed to the mixer, with the balance of the water being fed through low pressure nozzles.
Apparatus for mixing calcined gypsum comprising a top cover and a disk-shaped rotor comprising a rotor body with teeth along the periphery for mixing calcined gypsum with a metered amount of water and other ingredients to form a gypsum slurry, wherein the top cover contains a plurality of low pressure water jets and at least one high pressure water jet, with said high pressure water jet being aligned perpendicularly over the juncture of the rotor teeth and the rotor body, such that a vertical line defined by the high pressure jet and the juncture is perpendicular to a horizontal plane defined by the surface of the disk-shaped rotor, with a portion of the metered water introduced into the apparatus through the high pressure jet and the balance of the water is introduced into the apparatus through the low pressure jets, whereby the formation of lumps of gypsum at said juncture is substantially reduced.
Dependencies are inferred from the claim text.