| 摘要 |
794,510. Protective cut-out arrangement. RADIO HEATERS, Ltd. March 5, 1956 [March 14, 1955], No. 7388/55. Class 38 (5). Plastic sheet welding apparatus employing high frequency has its electrodes 20, 22 connected to a safety circuit comprising H.F. choke 11, relay 12, 17, auxiliary D.C. or low-frequency source 13, by-pass capacitor 15 and an earth connection. As plate 22 is also earthed any arcing between plates 20, 22 will complete the safety circuit so as to operate the relay 12, 17 to interrupt the supply to the equipment. In a modification (Fig. 2, not shown) the safety circuit is connected to welding apparatus with tuning stubs. The electrode 22 may alternatively be connected to the lower terminal of source 13 through a further H.F. choke and capacitor 15 replaced by two capacitors in series with their junction earthed. The Provisional Specification describes also an induction heating apparatus employing a work coil. |
