| 摘要 |
1509708 Sealing bags HAVER & BOECKER KG 19 Sept 1975 [4 Oct 1974] 43241/74 Heading B8C [Also in Division B5] The edge 11 of a filled plastics bag is sealed by conveying the bag through a welding station 20 in which the edge 11 is subjected to welding heat in the absence of contact pressure on the edge 11 and then conveying the bag through a cooling station 41 in which the edge 11 is subjected to a coolant fluid whilst being guided through a gap 33 in which the resulting seam 23 can expand in cross-section in a stress-free state, the cross-section of the seam being greater than the thickness of the bag walls. Filled bags are conveyed by a lower belt (not shown) driven in synchronism with conveyer chains 1, 2 driven by wheels 3, 4, tensioned by wheels 5, 6 and guided by rails 7, 8, the rail 8 being resiliently mounted. The edge 11 of each bag projects above the chains 1, 2 and is squared by a blade 12 for cutting a strip 17 off the bag edge, the strip 17 being removed by a conveyer 13. The squared edge is conveyed through the station 20 at which it is subjected to heat from two radiators 20, 21 to form a seam 23, Fig. 3, which, at the exit of the station 20, is guided by polytetrafluoroethylene-coated rollers 24, 25 mounted on adjustable levers 36, 37 and having a gap 40 therebetween, Fig. 4. At the station 41, the seam 23 is guided by chains 30, 31, Fig. 5, guided by rails 34, 35 adjustable to alter the gap 33 therebetween. Cooling air is supplied through nozzles of a blow tube 32. The thickness of the seam 23 can be adjusted by adjusting the width of the gap 33 and by metering the pressure or rate of flow of the cooling air. |
