| 摘要 |
1313939 Plate casting moulds ROSTERO SA 10 Aug 1970 38381/70 Heading B5A Flat smooth surfaced plates are cast from a polymerizable monomer in moulds defined between hollow heatable metal plates 9 suspended by wheels 12 from a rod 8 laterally extending across a sealed housing 1. Each plate carries on its major surfaces by means of spring clips or the like, glass plates 15, the plates being supported at their lower ends upon smooth ledges 13 carried by each metal plate and being movable away from their associated plates 9. Located between each pair of glass plates to define an upwardly open casting mould is a compressible gasket 33. In use, the distance between the metal plates and thus the width of the moulds is set by adjustable spacers 24 and the metal plates manually moved along the rod to form a series of open topped moulds into which the monomer is then cast. The plates are then firmly clamped together by screw threaded rods 46 manually rotated by means of handles 87. After this the chamber 3 within the casing is evacuated and the metal plates heated to degas the monomer and to initiate polymerization during which the cast material shrinks taking the glass plates with it. After de-gasing the chamber is returned to atmospheric pressure and the heating continued to complete the polymerization, the pressure/temperature relationship being controlled so as to prevent boiling of the cast material. Finally the moulds are unclamped the plates moved apart and the cast sheets carrying the glass plates removed. The glass plates are then removed from the cast sheets. The metal plates preferably comprise upper and lower sheets of steel or a light metal such as aluminium or an aluminium alloy bonded by an epoxy resin 9d to an external frame 9b. Internal spacers 17 divide the interior of the plate into a tortuous flowpath for a heat exchange liquid from an externally located pumping arrangement (see Figs. 3 and 7, not shown). |
