Apparatus for shrink packaging

Claim 1

Apparatus for packaging articles constituting the work to be packaged in heat-sealable, heat-shrinkable plastic film, comprising a tunnel means for conveying an item of work along a predetermined path through the tunnel with the work enwrapped in heat-sealable, heat-shrinkable plastic film and with the margins of the film overlapping one another at the bottom of the work for being heat-sealed together, said conveying means comprising a roller conveyor having a series of rollers inclined to the horizontal with one end constituting its entrance end at one end of the tunnel at a higher elevation than its other end constituting its exit end for gravity feed of the work through the tunnel, thermal radiation heating means mounted within the tunnel for directing thermal radiation toward the roller conveyor and hence toward work travelling on the conveyor through the tunnel for heating the film wrapped around the work as the work travels through the tunnel, at least one roller of said conveyor adjacent its entrance end constituting a heat-sealing roller for heating the said margins of the film on the bottom of an item of work as it travels over said heat-sealing roller to heat-seal the said margins of the film, said heat-sealing roller being blackened for being heated to sealing temperature by absorption of thermal radiation from said thermal radiation heating means, other rollers of said conveyor being unblackened and having a lower thermal radiation absorptivity factor than said heatsealing roller.