Patent GB-376761-A (GB)
Title: Improvements in or relating to electric vacuum tubes
IPC: H01J5/06
Filed: 1931-03-30
Abstract: 376,761. Discharge apparatus; switches. BRASCH, A., 4, Clausewitzstrasse, Charlottenburg, and LANGE, F., 7, Reichstagsufer, both in Berlin. March 30, 1931, No. 9580. Convention date, April 1, 1930. Addition to 365,609. [Class 39 (i).] The high-voltage discharge tubes of the parent Specification for generating hard X-rays and rapid cathode and canal rays are modified by forming the wall of the tube, or that part across which the discharge takes place, by assembling a large number of thin insulating and conducting layers flat upon one another in planes transverse to the axis of the discharge. The conducting layers are not connected to any external source of potential. In an assembly of metal washers 5, Fig. 1, and insulating washers 6, 7, the washers 5 extend inwards beyond the washers 6, 7 to screen the latter from the discharge and the insulating washers 7 extend outwards beyond the washers 5. The distance along the inner wall between adjacent washers 5 is made greater than the direct distance between the washers 5 by cutting away the insulating washers at the sides near their inner diameter or by inserting several insulating washers of different internal diameters as shown between adjacent washers 5. The washers are held together by the pressure due to the internal vacuum or by an insulating press. The vacuum is maintained by an outer tube or moulding or by a rubber tube fitting elastically over the tube or by making the washers 6 of rubber. Alternatively, rubber rings may be arranged in grooves in the washers 7 or between inner and outer insulating rings. The tube may be immersed in oil. To prevent the discharge striking the washers, the tube may increase in diameter towards the anode end. The insulating washers may be of high dielectric constant to increase the capacity and the disruptive strength of the wall and may be of cardboard, regenerated cellulose, porcelain, mica, glass, quartz or steatite. Organic insulating materials may be coated with a heatresisting material such as sulphur or glass. The end plates 1, 2 may be of metal or of insulating material carrying electrodes 3, 4. An emission source is provided at one end according to the polarity of the corpuscles generated. The tube may be energized from impulse generators producing very high voltages for small fractions of a second and may be used for the conversion of elements or for the treatment of cancer with hard radiations for short periods. The potentials may be sufficient to extract electrons from the cold electrode material. The generation of hydrogen positive rays is referred to. The Specification as open to inspection under Sect. 91 (3) (a) comprises also tubes in which the inner wall is grooved to receive metal rings and describes a lenticular form of tube made from two bell-shaped parts 12, 13, Fig. 5 (Cancelled), grooved or corrugated as at 16, concentric metallic cylinders 17 being arranged to overlap as in the upper half of the Figure or opposite one another as in the lower half. The application of the tube constructions to high-voltage rectifiers with a hot or other cathode and to vacuum circuit-breakers is specified. This subject-matter does not appear in the Specification as accepted.