Method for wet mixing cementitious slurry for fiber-reinforced structural cement panels
AssigneeUnited States Gypsum Company
InventorsLloyd M. George, Ashish Dubey, Eugene Scott Stivender
Life of this patent
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Abstract
A process employing a wet mixer having a vertical mixing chamber for forming a wet slurry of a cementitious powder and liquid. The vertical mixing chamber is designed to provide the required amount of mixing to provide thoroughly mixed, uniformly thin slurry within a mixing residence time that allows for adequate supply of slurry to ensure continuous operation of an associated cement panel production line. Gravity feed for supply of cementitious powder and water to the slurry mixing area of the chamber is also disclosed.
Claims12
A method for preparing lightweight cement composite slurry which can be supplied in a continuous curtain for uniformly covering a thick layer of fiber in the production of a reinforced structural cement panel comprising:
- feeding a dry cementitious powder comprising cement, gypsum and aggregate from a bin into a horizontal powder mixer having a horizontally mounted screw auger;
- discharging the dry cementitious powder mixture from the screw auger into a horizontal pre-mixer equipped with a paddle rotated about a central horizontal axis by the screw auger;
- feeding a liquid stream comprising water, into the horizontal pre-mixer through an inlet;
- mixing the cementitious powder and liquid to form a wet powder slurry mixture;
- dropping the pre-mixed powder and liquid mixture from the upper portion of a vertically oriented mixing chamber to a lower portion of the vertically oriented mixing chamber equipped with a paddle mixer rotated about a vertical shaft by a top mounted motor;
- mixing the water and powder in the lower portion of the vertically oriented mixing chamber;
- and
- pumping the slurry to a slurry headbox for depositing the slurry as a continuous curtain on a thick fiber layer on a web in a panel production line,
- wherein the powder and liquid are mixed for an average mixing residence time in the mixing chamber lower portion of about 10 to about 360 seconds while a spinning paddle applies shear force to the slurry in the mixing chamber to mix the powder and water to produce a uniform slurry of a lightweight cement composite that has a consistency that will allow the slurry to uniformly cover a thick layer of fiber on a web to produce a fiber reinforced structural cement panel.
Dependencies are inferred from the claim text.