Patent GB-599612-A (GB)
Title: Electron discharge devices and associated circuits, particularly for ultra-high-frequencies
IPC: H01J19/80
Filed: 1944-09-22
Abstract: 599,612. High-frequency discharge apparatus. MARCONI'S WIRELESS TELEGRAPH CO., Ltd. Sept. 22, 1944, No. 18178. Convention date, Oct. 30,1942. [Class 39 (i)] A high-frequency electron discharge device has an anode sealed into one end of the envelope 10, Fig. 1, and formed with one or more channels of U-shaped cross-section within which is or are disposed a similarly shaped cathode and grid assembly or assemblies. The anode 14 is either frusto-conical with two parallel U-sectioned channels, Figs. 1, 2, or frusto-conical with a single annular channel, Figs. 4-6 (not shown), or cylindrical with an annular U-sectioned channel cut into the cylindrical surface, Fig. 7. (not shown). The frusto-conical anode 14, Fig. 1, is provided with two parallel U-shaped channels 14<1>, within which are disposed U-shaped grids 13 and cathodes 11. The U-shaped grids 13 are secured to an apertured disc 20, Fig. 2, by angle members 13<1>, and the disc 20 is supported by members 21 from an annular ring 18 sealed through the envelope 10. The indirectly heated cathodes 11 are formed of flat ribbon folded to U-shape or of two strips conductively joined along one edge and are supported from an apertured disc 22 by legs 11<1> and by a U-shaped member 11<11>. The disc 22 is sup. ported by fingers 23 from an annular ring 19 sealed through the envelope 10. Heaters 12 are provided for the cathodes 11. The cathode heater leads 26, 27 are provided with a byepass condenser 28 formed by the conductive disc 22, an apertured insulating disc 29, conductive plates 30, 31, insulating discs 34, 35 and clamping plates 36, 37, the entire assembly being secured together as a unit. The plates 30, 31 are provided with legs 32, 33, 32<1>, 33<1>, to which the heater wires are soldered, the latter being cross-connected so as to place the heaters in parallel. During manufacture, the cathode 11 and grid 13 are assembled as a unit and maintained in spaced relation by glass beads 24, Fig. 1, before being secured to the annuli 19, 18 respectively. The resonator walls 41, 43, 47 are provided with spring fingers 45<1>, 46 and 50 which engage the cathode and grid rings 19, 18 and the anode flange 16 respectively ; the resonators may be provided with apertures so that a cooling medium can be directed over the ring seals of the discharge tube. The anode 14 has cooling fins 17. Feed-back is provided between the two resonators by a transmission line 54, 56, 57, the amount of which can be varied by rotating the loop 54 by knob 55 or by sliding the member 57 in a slot 58 by member 59. Alternatively, the feed - back arrangement may be dispensed with if the grid-cathode resonator is excited by energy from an external source. In the modified construction of Fig. 4 (not shown), the cathode comprises two concentric collar-like members spaced apart by rods and enclosing a plurality of heaters located between the spacing rods, the collars being joined at one edge thereof so as to provide the required U-shaped crosssection. One heater lead of each heater is connected to a disc directly supporting the cathode and the other heater lead is connected to a ring insulatingly supported from the cathode disc. An insulating spacer is supported on the cathode disc and extends into a bore in the anode block so as to maintain the correct grid-anode spacing. In the modified construction of Fig. 7 (not shown), the anode is made in two parts secured together by a screw.' The cathode is in this case formed by a pair of flat ring-like members spaced apart by rods and enclosing a plurality of heaters, the inner edges of the rings being joined so as to form the required U-shaped cross-section. The cathode supporting structure includes two conducting rings insulated from one another, one end of each heater being conductively connected to one ring and the other end to the other ring.