GB295321A - Cathode ray oscillographs - Google Patents

Abstract

295,321. Norinder, E. H. Aug. 9, 1927, [Convention date]. Vacuum tubes.-Cathode-ray oscillographs for automatically recording electrostatic, and magnetic field variations such as those produced by lightning discharges and other transient disturbances are provided with a target electrode 9, Fig. 7, intercepting the undeflected cathode beam and preventing its impinging on the recording surface and with oppositely acting deflecting devices such as plates 8, 11 or coils in front of and behind the target 9 and deflecting the beam around the target 9. The recording surface, such as a photographic film in the metal body, 1, is moved relatively to the beam transversely to the defections. The film may be rapidly rotated or the beam oscillated transversely to the defections, by the field of a coil carrying alternating ing current. To record in an unfogged portion of the film, the origin of the record may be deviated by deflecting plates or coils 13 supplied with steady current, the coils being preferably inside the tube. An apertured screen 12 between the parts 11, 13 concentrates the deflected beam. The target 9 is maintained at a definite potential or insulated but is preferably earthed. The tubular anode 6 may be watercooled and is earthed and the cathode 5 is maintained at a negative potential of say 60,000 volts. On connecting the plates B, 11 as shown to earth and to a potential divider B connected to a highpotential line A. no record is obtained except for a lightning discharge &c. The centre of the record has a. dark band due to the, target 9 and the width of this band may correspond to the normal voltages in the line A. The tube is of metal except for the glass tube 4 connecting the anode 6. and the cathode 5. The plates 8. 11, the screen 12 and the coils 13 are mounted in removable frames 7, 10 in metal tubes 3, 2. The parts 1, 2, 3, 6 have conical joints and the ends of the tube 4 are cut off and ground at right angles to the axis of the tube. The leads 18, Fig. 2, to the parts 5, 8, 11, 13 are insulated from and supported by conical plugs 14 detachably sealed by grease into seatings in a ferrule 15 and in the tubes 2, 3. Vacuum-maintaining compounds may be used at the joints at the ends of the tube 4. The Specification as open to inspection under Sect. 91 (3) (a), comprises also a reference to a gas pressure of 6-10 microns in the tube 4 and 1 micron in the parts 1, 2. This subject-matter does not appear in the Specification as accepted.