System for metering and film packaging of bitumen and like materials

摘要

A system for metering and film packaging of bitumen and like materials that are solid at room temperature and molten liquid when heated. The packaging film is thermoplastic, having a melting point not exceeding the temperature of molten bitumen. The material of the packaging film in liquid form is compatible with bitumen without deleteriously affecting the characteristics of the bitumen. In the system, bitumen in a hot molten state is pumped at a filling station into empty molds that are lined with release material. The fluid bitumen is metered at the filling station to supply a predetermined quantity in each mold. The filled molds are conveyed through a lengthy cooling station that may include a water bath and after a suitable time, e.g. 2 to 4 hours, the bitumen solidifies into slabs. The individual molds are comprised of multiple sections including a removable bottom and side walls that can shift from a closed mold-defining position to a discharge position in which the side walls are spaced apart sufficiently to permit the solidified slab to leave downwardly through an open bottom. The system includes an ejection station at which the molds are successively opened and the bottoms momentarily removed to permit pushers to force the slabs downwardly out of the molds onto a conveyor that leads the slabs to a wrapping station at which the cooled solidified slabs are packaged in a biaxially oriented stretched heat-shrinkable thermoplastic film. Thereafter the enveloped slabs are transported through a shrink tunnel to contract the wrapped film tautly about the slab. Next the shrink-wrapped slabs are stacked on pallets ready for shipment. The molds from which the slabs were discharged are closed, the bottoms reapplied and the molds are recycled.