GB533727A - Improvements in x-ray apparatus - Google Patents

Abstract

533,727. X-ray tubes. MACHLETT LABORATORIES, Inc. Nov. 16, 1939, No. 30218. Convention date, Nov. 17, 1938. [Class 39 (i)] [Also in Group XX] X-ray apparatus comprises a tube with a rotary anode having a substantially flat target face and a cathode which directs an electric stream on it to one side of its axis of rotation the tube being supported in a housing with its longitudinal axis inclined to that the X-rays pass through a window in the wall of the housing. In the form shown, the metal oil-filled housing for the tube consists of upper and lower parts 21, 22 connected by horizontal flanges and ray proofed where necessary by a lead lining 27. A window 28 which may be of a phenolic condensation product, is held by a threaded ring 30 and has an inner wall 28b which lies at an angle to the longitudinal axis of the housing and parallel to the adjacent part of the wall of the tube. The tube is inclined, and is supported at one end by being lashed by cords 40 to an inverted forked bracket 36 partly embracing the tube neck 34, and at the other end by an inverted fork bracket 41 in which the tube neck is held by a cross-bar 44. The supply cables enter the casing through insulating thimbles secured in neck portions extending rearwardly from the ends of the upper part of the casing. The tube shown comprises an anode in the form of a flat disc 91 of tungsten or other suitable material, mounted by a stem 88 on a rotor formed by a cylinder 75 of ferromagnetic material in which is embedded a copper squirrel cage consisting of bars 95 connecting end rings 94. The rotor is carried by ball bearings on a shank 59 sealed by a suitable seal 73 to a re-entrant portion of the end of the tube. The stator, consisting of the laminated core 70 and windings 69 is mounted by a bracket 71 in the housing so as to surround the rotor. The cathode comprises two coiled filaments 106a, b, Fig. 10, of different lengths, arranged in semi-cylindrical channels in a block 104, the surface of which is formed as two inclined fans which direct the two electron streams on to the same area of the target. The block is carried by an arm 103 mounted on a slotted sleeve 99 secured by straps 100 to a tube 98 through which pass the filament leads. The tube 98 may contain also a conductor 110 coated with gettering material.