Patent ID: 7513963

Claim:
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 an upper portion of a vertically oriented mixing chamber equipped with a paddle rotated about a central vertical shaft of the paddle; dropping the dry cementitious powder mixture from the upper portion of a vertically oriented mixing chamber to a lower portion of the vertically oriented mixing chamber; feeding a liquid stream comprising water, into the upper portion of the vertically oriented mixing chamber through multiple inlets, separately from the dry cementitious powder; dropping the liquid stream from the upper portion of a vertically oriented mixing chamber to the lower portion of the vertically oriented mixing chamber so that the liquid stream contacts the powder in the lower portion of the chamber equipped with the paddle mixer; 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.