| 摘要 |
797,202. Dielectric heating. RADO, L. July 5, 1954 [July 23, 1953], No. 20486/53. Class 39(3) In welding thermoplastic material by dielectric heating between opposed non- rotatable H.F. electrodes, at least one electrode 1, 3 presents a welding surface of semi-circular or quarter-circular cross-section of a radius greater than the thickness of the material to be welded, so that the electrodes on meeting touch each other only on a line. Both electrodes may be semi-circular or one electrode may be flat. The thermoplastic is thus sealed along a line 6 and is either cut along the line or is thinned to be easily tearable. A liquid filled thermoplastic tubing 5 of polyvinyl chloride may thus be sealed at intervals between the electrodes which may have a thin rubber covering 3a covered by a this sheet of cellulosic material. Specifications 599,174 and 675,073 [both in Group XVII] are referred to. |
