GB1120432A - Improvements relating to dielectric heating apparatus - Google Patents

Abstract

1,120,432. Oscillator circuits; R.F. couplings. RADYNE Ltd. 24 Sept., 1965 [21 Sept., 1964], No. 38449/64. Headings H3F and H4A. A radio frequency heating apparatus comprises an oscillator in which a valve 1 is positioned inside and near the lower end face of a combined screening and resonating cavity 2, the grid or cathode terminal of the valve 1 is connected to the said lower end face, an inductive element 5 is connected between the anode cap 4 of the valve 1 and the upper end face 6 of the cavity 2, and an output connection 8 is tapped along the inductive element 5. As described, a spring pad 4a is provided upon the anode cap 4 and an isolating capacitor 4b is intermediate it and the lower end of the tubular inductive element 5, which has an annular surround 12 providing a capacitance to the shell of the cavity 2. The upper end of the element 5 extends to the upper end face 6 of the cavity 2, and is connected thereto. From tapping extensions 7, which may be from 0À3 to 0À5 of the distance down the element 5, symmetrically arranged parallel conductive strips 8, Fig. 2 (not shown) are taken through holes in the upper end face 6 to a fixed electrode 9 of a variable output capacitor, the other electrode 10 of which is hinged and is connected through a conductor 11 to the heating apparatus.