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1494231 Continuous casting of fibre-reinforced plaster ACI TECHNICAL CENTRE PTY Ltd 25 March 1975 [26 March 1974] 12463/75 Heading B5A [Also in Division B1] A plaster slurry is cast in a procession of moulds, and fibres deposited on the cast slurry and forced into its surface. The moulds are open ended and interconnected end-to-end by flexible strips so that a continuous sheet of plaster is cast and finally cut into lengths. As described, a plurality of moulds 27 having flat floors and side walls, are formed into a procession by bridging rubber strips, and are moved over a support frame 21. Plaster and water are continuously cast from a mixer 29 (see Divisions B1-B2) into the moving moulds on top of a decorative facing sheet. Sisal or fibreglass fibres (as randomly oriented chopped lengths, rovings, continuous meandering strands, or a random mat) are applied by a dispenser 44, and then forced to the bottom of the plaster layer by a pair of fluted rollers 56. A further layer of fibres is applied by a dispenser 44a, and forced into the plaster upper surface by a pair of open mesh rollers 56a. Any plaster on the mould side walls is wiped back into the mould by driven, toothed rubber discs (62, Fig. 11, not reproduced) and the upper plaster surface is levelled by an endless plastics-coated rubber sheet (64, Fig. 10, not reproduced). The plaster is cut to length over the bridging rubber strips, the moulds slightly separated, and lowered on to a return track. Adjacent the mixer 29, the mould walls are hinged down, the cut sheets removed to a drier by an air blast and vacuum cups, and the moulds raised again to the level of frame 21. The fibre dispensers 44, 44a and pairs of rollers 56, 56a are duplicated so that one of each pair can be raised by cylinders 46, 46a and run away on horizontal tracks for repair or filling. Each fibre dispenser includes several distributing heads (53, Fig. 6, not reproduced) that reciprocate over the moulds to drop the fibres into a turbulent air stream that ensures random orientation.
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