| 摘要 |
845,814. Sealing by dielectric-heating. RHENOPACK, G.m.b.H. July 22, 1958 [July 25, 1957], No. 23453/58. Class 39(3). [Also in Groups VIII and XVII] Cushion type packages are formed from a flexible tube 1 being filled with a liquid or pasty material by first flattening an area to be sealed by a compressed air jet, then heat sealing the flattened wall parts together and finally cooling the sealed surface with the air jet. In Fig. 1 the heat sealing is performed by two high frequency electrodes 5 reciprocable against the tube 1 from within housings 2, the compressed air flowing from an annular passage 11 surrounding each electrode. In a modified construction, Fig. 4 (not shown), the housing .2 is constructed such that the air does not flow over the surface of the electrode 5 but escapes through an annular shaped orifice in the end face of the housing. In a further modified form, Fig. 5 (not shown), the compressed air passes through a bore in the electrode. As the housings 2 in Fig. I are moved towards the tube 1 they engage stops 14 to prevent contact with the tube 1, the electrodes 5 being propelled forwardly by inertia until they contact the tube 1 whereafter they are retracted by springs 8. In a modified construction the housing 2 may be moved towards the tube 1 by a first air operated piston and the electrode 5 is then moved into engagement with the tube 1 by a second air operated piston. In another construction such movements are controlled by a linkage system coupled to the housings 2 and operated by cams secured to a revolving shaft. |
