GB473530A - Improved rectifier comprising an ionic rectifying tube having an incandescent cathode - Google Patents

Abstract

473,530. Discharge apparatus. NAAMLOOZE VENNOOTSCHAP PHILIPS' GLOEILAMPENFABRIEKEN. April 19, 1937, No. 11170. Convention date, April 21, 1936. [Class 39 (i)] In an ionic rectifying tube 3 having an incandescent cathode 1, the discharge path between the cathode and anode or anodes is arranged in a magnetic field, the lines of force of which connect the cathode and anodes. This enables pressures of less than 0À01 mm. of mercury to be employed in the tube to minimize the risk of back ignition without appreciably decreasing its life. In the full-wave rectifier shown, the anodes 2 are made of magnetic material and the magnetic field is produced by a permanent magnet 5 outside the tube, with its poles adjacent the anodes. A non-magnetic screen 7 prevents direct discharge from the cathode to the anodes. The magnetic field may also be produced by an alternating current in synchronism with the current to be rectified, or by a current pulsating in synchronism with the anode currents, so that the field at each anode disappears during the nonconducting phase of the anode. The tube is preferably filled with mercury vapour obtained from a supply of mercury in a cooled attachment of the tube. The required low pressure may be secured by keeping the mercury supply at a temperature at which its vapour pressure corresponds to the pressure desired in the tube.