| 摘要 |
<p>1468176 Packaging radiographic films AGFAGEVAERT 10 April 1974 [27 April 1973] 20183/73 Heading B8C Radiographic films are packaged between peripherally sealed thermoplastic sheets, for example of PVC or polyethylene. The longitudinal seals are located at the edges of the film to prevent movement of the film within the package and to allow exact abutment of the edges of the package when it is spirally wrapped around an article, for example a tube, an extended length of which is to be examined. Sealing may be effected ultrasonically or by high frequency electrodes. One example of a package comprises a pair of films 13, 14 sandwiched between paper/lead laminates 15, 16 all located within a pair of peripherally sealed sheets 11, 12. A tab may be welded to one end of the package, pulling off of the tab weakening the seals and facilitating easy opening of the package. A package may be made by passing a film assembly 20 and a pair of covering films 11, 12 between a pair of transverse welding high frequency reciprocable electrodes 27, 28 and a pair of longitudinally welding high frequency rotatable electrodes 29, 30. Packages thus formed are either completely separated by knives 34, 35 or partially separated by them and wound on to a storage reel 36, 37. The transverse welding electrodes may be actuated by sensing the arrival of the leading edge of a film assembly as by a radiation detector device or by a pivoted roller device.</p> |
