| 摘要 |
796,913. Seaming non-metallic sheet materials. FENWAL LABORATORIES, Inc. July 31, 1956 [Aug. 9, 1955], No. 23667/56. Class 42 (1). [Also in Group XI] Sheets 11, 11 are sealed to each other and to tubes 12 simultaneously by establishing an alternating electric field between the sheets and and a second harmonically unrelated field between the sheets and the tubes. The first field is provided by a radio frequency generator 19 connected to the dies 14, 14 while the second is provided by a generator 27 which is connected to a rod electrode 16 inside the tube 12 and to the dies 14 through a capacitor 22 having a low impedance at the generator frequency. Variable capacitors 25 and adjustable taps 24 on an inductance 21 control the load impedance on the generator 19 and the voltage applied to the dies 14. A number of tubes of different shapes and sizes may be simultaneously sealed to the sheets 11, 11, the rod electrodes being connected to the generator 27 through capacitors chosen to produce the same voltage gradient for each sheet to tube seal. The Specification describes a prior apparatus in which the sheet to tube and sheet to sheet seals are effected in succession bv separate generators brought into operation by a switch. |
