Clay mould - has shaped filter layer as the mould for water to be forced from the clay through the filter by high pressure

摘要

To produce clay blanks (6), in a thin walled or solid or hollow shape, the fluid clay material is fed into a water permeable mould of negative shape to fill it. A high pressure is applied, pref. above 100 bar, and water is forced out of the clay material. Pref. after moulding, remaining fluid clay material is removed and the moulded clay in the mould is subjected to further pressure by air at a high pressure, pref. above 100 bar. Compressed air is used to remove the blank (6) and/or to extract water from the mould and/or to remove surplus fluid clay. Within a pressure sealed housing a pressure resistant filter layer (5) gives the negative shape of the blank (6) to be formed. A support (4) between the filter layer (5) and the housing has hollow zones to lead off water pressed out of the clay through the filter layer (5). A connection (7) gives the feed of the prepared fluid clay and a connection (8) for compressed air removes surplus liquid clay. The housing is fitted with at least one opening (9). The housing is in at least two parts (2.1,2.2) and at least one frame is round the housing. The filter layer (5) is a porous fired ceramic material. The support (4) between the filter (5) and the housing is loose gravel bonded by synthetic resin. A compressed air connection is fitted to the opening (9) in the housing. A membrane separates the clay and the pressure medium. Inserts (12), with low or no porosity, cover part of the filter layer (5). The filter layer (5) has zones of different porosity and different thicknesses. ADVANTAGE - The process does not require plaster moulds so mould drying and energy costs are eliminated.