GB1365986A - Packet sealer - Google Patents

Abstract

1365986 Sealing packages IMPERIAL CHEMICAL INDUSTRIES Ltd 6 June 1973 [22 June 1972] 29332/72 Heading B8C [Also in Division B5] A method of sealing a folded sealable wrapper about a packet 1 comprises conveying a wrapped packet past a member 11 positioned to retain the folded wrapper in position on the packet, maintaining between the packet 1 and the retaining member 11, a movable surface, advancing the surface solely by engagement with the packet relative to the retaining member in the direction of motion of and at substantially the same speed as the packet, and supplying sufficient energy to the area of wrapper in contact with the moving surface to seal the wrapper in that area. As shown a series of packets 1 each wrapped in a vinylidene chloride/ acrylonitrile copolymer coated polypropylene film is fed in a packet-pushing pocket sequence along a base-plate 2 between side walls 3 which retain in position folded end flaps 4 of the wrappers. The packets are fed between a pair of polyethylene terephthalate endless belts 5 within each of which is positioned a retaining member 11 provided with internal electric heaters and temperature sensors (not shown). The surface of each member 11 in contact with the belt is coated with polytetrafluoroethylene to reduce frictional drag between the belt and the member 11, the arrangement being such that as each wrapped packet passes between the members 11 the flaps 4 are heat sealed. The belts themselves may be heated to effect heat sealing and may also be used to transfer matter such as labels to the sealed areas of the packet. Sealing may be effected by other than heat, e.g. by ultrasonic bonding techniques or the end flaps may be coated with pressure-sensitive adhesive, cold adhesive, hot-melt adhesive or heat sealable polymeric adhesives.