摘要 |
Unusually strong and highly perforated plates are formed by pressurized filtration of a suspension of chopped ceramic fibers in an aqueous dispersion of colloidal alumina or colloidal silica through a mold (10) having a perforated filter base (20) and a pin support base (12) having pins (14) that extend through and beyond the perforations (25) of the filter base (20). Pressurized filtration is preferably conducted by applying vacuum on the downstream side of the mold. When the resulting compact layer of chopped fibers (24) deposited on the perforated filter base (20) has the desired thickness, filtration is stopped. The perforated filter base (20) and pin support base (12) are moved apart to retract the pins (14) from contact with the perforated compact layer of chopped fibers (24) which is transferred to a drier. By operating the drier at a temperature not exceeding about 650.degree.F (343.degree.C), the compact layer of chopped fibers (24) is converted into a novel unsintered, perforated plate of unusual strength.
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