Pittsburgh Corning Corporation

Howard Beattie Johnson

Harold Lloyd Weaver

Fred Simms Coffey

A dilute slurry that includes mineral wool fibers, a clay binder, other binders and a flocculent is introduced into a forming tank at several elevations and with sufficient velocity to circulate toroidally therein. A mandrel having the desired configuration of one surface of the shaped article is lowered into the forming tank and rotated at a preselected speed. Vacuum is applied to the rotating mandrel and a substantially uniform layer of solids is deposited on the outer surface of the mandrel while the filtrate is withdrawn through an internal portion of the mandrel and conveyed to a filtrate recovery tank. After a layer of a preselected thickness is deposited on the outer surface of the mandrel, the mandrel is removed from the forming tank and vacuum is maintained on the mandrel to reduce the water content of the accreted fibers to between about 40 to 65% by weight water. Thereafter, while on the mandrel, the accreted fiber-shaped article is trimmed to provide an outer surface of a desired configuration. The trimmed article is thereafter sprayed with a coating material while vacuum is maintained on the mandrel so that the coating material penetrates the surface of the shaped article. The shaped article is thereafter removed from the mandrel and trimmed to provide a fibrous shaped article having a desired configuration and thickness.

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Bradford, PA, United States of America

Howard Beattie Johnson