| 摘要 |
<p>1,103,466. Closing filled bags. A. WINDMÍLLER, and M. GENNERICH, [trading as WINDMÍLLER & HÍLSCHER]. 9 March, 1965 [10 March, 1964], No. 9971/65. Heading B8C. [Also in Division B5] The closure seal of a filled plastics bag is formed by jointly turning over the edge portions 4a, 5a of the bag walls 4, 5 adjacent to the filling end on to an outside surface, e.g. the wall 4, of the bag, and heat sealing the inner ply 4a of the back-folded portion 7 to the outer ply 5a thereof at 6b and to the outside surface 4 of the bag at 6c by first applying heat without pressure and then applying pressure. During the sealing operation, the walls 4, 5 become sealed together at 6a but, during transport and storage, the walls 4, 5 become spread apart near the seal and they peel apart in the portion 6a of the seal. In one embodiment of apparatus for effecting the seal, Figs. 4 and 5, bags 1 are fed from a filling station on a conveyer in the direction of the arrow 11. The open bag end is gripped, e.g. by an operator, and the portion 7 is applied over a guide rail 12. The portion 7 moves into a U-section guide belt 13 driven at the same speed as the conveyer 10 and having incisions 16 in the limbs thereof to effect reversal thereof. The bag end is held against the surface of the belt 13 by suction from a pump connected to a chest 18 connected to holes 17 in the belt 13. The rail 12 terminates in a slot nozzle 20 which discharges hot air to heat the bag end. When the bag leaves the belt 13 with the end heated to the sealing temperature it passes between a pair of pressing belts 22 to effect the seal. The rail 12 may be coated with an anti-sticking agent and may serve as a preheating bar. In a modification, Fig. 7 (not shown), the bag end may be heated by a radiator 25 having electrical resistance wires embedded therein. The guide belt 26 comprises holes 17 in the web and holes 27 in the limbs thereof and the suction chest 28 embraces three sides of the belt 26. In another embodiment, Figs. 8-11 (not shown), the portion 7 of the bag 1 being fed by the conveyer 10 is folded over the rail 12 and then moves through a folding roller 30 and between belts 31, 32 driven at the same speed as the conveyer 10. The back-folded end of the bag 1 protrudes beyond the belts 31, 32 by an amount corresponding to the desired width of the heat seal. The sealing heat is applied by radiators 37, 38, 39 containing electrical resistance wires. Cooling elements 40, 41 prevent excessive temperature rise of the belts 31, 32 and of the bag material adjacent thereto. Pressing rollers 42, 43, 44, 45 which may be fluid cooled press the heated protruding end to effect the seal. In a modification, the roller 30 is replaced by a deflecting plate.</p> |
