GB936996A - Improvements in or relating to electron discharge devices - Google Patents

Abstract

936,996. Thermionic cathode tubes. TELEFUNKEN G.m.b.H. Dec. 22, 1959 [Dec. 23, 1958], No. 43429/59. Class 39 (1). In an ionization monometer comprising a cathode 6, an ionizing electrode 9 and a collector 10 for collecting positive ions, the cathode 6 being outside the ionizing electrode 9 and the ionizing electrode 9 surrounding the collector, the electrodes are all connected to terminal pins all disposed at the base of the envelope, the pin connected to the collector electrode being surrounded by the pins connected to the cathode and ionizing electrodes, and a portion of the envelope is so formed that the electrical leakage path from the pin connected to the collector to any other pin is longer than the distance between the respective pins. The directly heated filamentary cathode 6 is held taut by a spring 7 secured to pillar 8, the ionizing electrode 9 is a helix and the collector 10 is a wire. The ionizing electrode helix may have flat spiral terminations. The struts or other supports of the ionizing electrode are made integral therewith so that in degassing they can be made incandescent together with the ionizing electrode. A large insulation resistance between the collector 10 and other electrodes is achieved by forming the envelope with a collar having a reentrant portion. There may be two cathodes. The ionization monometer measures the pressure in its own enclosure or in a vessel coupled thereto.