METHOD OF MOULDING OF ACRYLIC PLASTIC PRODUCTS, MAINLY OF HEMISPHERICAL PORT-LIGHT, AND INSTALLATION FOR MOULDING OF PRODUCTS OF THICK ACRYLIC PLASTIC Russian patent published in 1997 - IPC

FIELD: moulding of acrylic plastic products of a complex shape of very thick acrylic plastic, for instance, port-lights for underwater apparatuses. SUBSTANCE: the method consists in the fact that the blank of acrylic plastic is clamped around the edges between broaching and clamping rings; prior to clamping or after it the blank is heated to a high-elastic state, after that local peripheral cooling of the blank edge is performed, then the product is moulded through a broaching ring to the preset height producing an air pressure differential near the blank (or by high pressure, or air rarefaction), and after the product being moulded attains the preset height it is slowly and evenly cooled, the air pressure and clamping around the product edges remaining unchanged; after the product is cooled the pressure is relieved and the product is unclamped. To realize the described method, a special installation for moulding of thick acrylic plastic product, using a branching ring, clamping ring and a rubber seal is offered; the sealed cavity between the product blank and one of the rings is connected to the source of pressure differential; device for local peripheral cooling of the blank edge located around the edges of the installation. The device for local peripheral cooling of the blank is made in the form of a square-section hollow tube fixed on the end face of the broaching ring, and another square-section hollow tube fixed on the end face of the clamping ring; the tube interiors are connected to the coolant feed and drain tubes. EFFECT: facilitated procedure. 4 cl, 4 dwg