GB767326A - Improvements relating to high frequency heating equipment - Google Patents

Abstract

767,326. R.F. couplings. RADIO HEATERS, Ltd. July 12, 1955 [July 16, 1954; Dec. 1, 1954[, Nos. 20821/54 and 34847/54. Class 40(7) Coupling in the output circuit of highfrequency dielectric heating equipment is effected by means of a single turn metal strip coil mounted on supports at its four corners and connected as part of the generator " tank " circuit and a secondary coil consisting of a single turn of metal strip surrounding the first coil and threaded through the gap between the pairs of supports. In one embodiment the tank circuit includes a capacitor comprising interleaved plates 1 and 2. Plates 1 are supported on insulators 3 and plate 2 supported on further insulators attached to the casing 10 and not visible in the Figure. Connected to the plates 1 is a bracket 5 of considerable width on which are mounted a pair of conductive pillars 6 supporting the corners of one end of strip metal coil 7. The other end of coil 7 is supported by a similar pair of pillars 8 on bracket 9 attached to plate 2. The secondary coil 14 extends from output terminal 13, mounted on insulating panel 12, round coil 7 and between the pairs of pillars 6 and 8 and is then attached to earthed work table 11. In a modification (Figs. 3 to 5, not shown) the high potential end of the secondary coil is attached toa metal rod carrying the movable plates of a variable condenser. Interleaved fixed plates are connected together and to the output. The condenser is adjusted by means of a worm drive and insulating strips connecting link. If the length of the tank circuit is considerable intermediate supports may be provided necessitating the use of two or more secondary coils which may be in parallel or coupled to independent outputs.