GB1375580A - - Google Patents

Abstract

1375580 Seaming non-metallic sheet material EASTMAN KODAK CO 9 Nov 1971 [9 Nov 1970] 51983/71 Heading B5K [Also in Division B8] Apparatus for continuously forming liquid filled pods P each having a seal 18 which ruptures when the pod is compressed, comprises a heatsealer 25 for making the seal 18 between superposed thermoplastics-coated webs 10, and a further heat-sealer 26 which strengthens seal 18 at regularly spaced intervals to form mid-regions 19 which will not rupture. A further heat-sealer 27 makes the other longitudinal seal 17 while a nozzle 28 is inserted between the webs to introduce the liquid, which may be a photographic developer. Rotary sealing device 31 then forms transverse end seals 16 and a central partitioning seal 20. Finally, a rotary cutter 32 severs the pods along the seals 16 for discharge on to conveyer 33. Each heat sealer 25, 27 comprises heater bars 38, 39 with sealing jaws 38<SP>1</SP>, 39<SP>1</SP> and heating elements 40 and thermocouples 43 controlling temperature. Upper jaw 38<SP>1</SP> is retractable against spring 57 when holder 48 is pivoted about pintle 51. At higher web speeds, an electric sonic vibrator 62 is mounted on holder 48 to reduce friction at the jaws. Mid-sealer 26 comprises a rotating drum bearing eight temperature-controlled heaters 69 beneath a cup position 66 carrying the webs, the seal 18 of the webs being pressed on the shaped heaters by four spring-loaded rollers 77. Transverse sealer 31 comprises eight heated sealing jaws 95 on heated ring 96 which rotates to carry the webs past ironing heads 98. Each jaw carries two surfaces 95 to form seals 16 and a central surface 105 to form partition seal 20. Heads 98 are moved radially inwards by arcuate cam 130. Liquid is supplied by a constant discharge pump synchronized with the web drive so that each pod receives the same amount of liquid regardless of the web speed. The webs may comprise a base of kraft paper, a layer of metal foil, and a thermoplastic coating.