Patent GB-456243-A (GB)
Title: Improvements in or relating to single phase mercury vapour rectifier valves
IPC: H01J13/48
Filed: 1936-02-08
Abstract: 456,243. Mercury - vapour rectifiers. NAAMLOOZE VENNOOTSCHAP PHILIPS' GLOEILAMPENFABRIEKEN, Emmasingel, Eindhoven, Holland. Feb. 8, 1936, No. 3934. Convention date, March 30, 1935. [Class 39 (i)] A single-phase rectifier comprises a cylindrical container, which consists of a lower metal part, containing the mercury cathode, and an upper glass part sealed thereto, igniting and maintaining anodes located immediately above the cathode and a main anode arranged above the auxiliary anodes in such manner that its axis is parallel to that of the container wherein the seals between the glass and metal parts are separated from the discharge space by screens or by the construction of the container. A metal part 1, Fig. 1, is provided with a water jacket 2 and is sealed to a glass part 6 provided with leading-in wires 27 for the auxiliary anodes 12, 13 and with a joint 7 for the leading- in wire to the main anode 11. An insulating tube 10 on the anode stem 8 supports a member 14 to which is clamped the conducting support 15 of the immovable maintaining anode 12. An insulating tube 16 surrounds the conductor 15. The movable ignition anode 13 is supported from an iron armature 22 through the conducting member 18 which is adapted to slide within an insulating tube 19 clamped to the support 14. Recesses in the anode house the auxiliary anode supports. A magnet 25, supported on the member 14, is adapted upon energization of the winding 24 on the tube to attract the armature 22 and withdraw the electrode 13 from the mercury to ignite the arc. The joints are screened from the discharge by members 29, 30 in which holes 32 are provided to facilitate the return of condensate to the cathode. Members 26 screen the conductors 27 from the discharge. Three of the valves shown in Fig. 1 are connected to a three-phase supply as shown in Fig. 2. Auxiliary secondary windings 40 are connected at their ends through chokes 42 and magnet coils 44, 45 respectively to the maintaining and ignition anodes 12, 13 and through a centre tapping to the cathodes 17. When connected to a three-phase supply, the coil 45 is energized, due to the contact between the electrode 13 and the cathode, to lift the electrode 13 to ignite the arc. Maintaining arcs are then struck to the anodes 12, 13 and the discharge currents energize the coils 44, 45 to maintain the electrode 13 in its raised position. In another form, a hollow anode 50, Fig. 3, is screwed to a metal member 54 which is sealed to glass portions 51, 59 of the container and constitutes the anode terminal. An insulating member 56 is clamped between the anode and the member 54 through a metal ring and, with the insulating member 57, screens the joints from the discharge. A conical polepiece 73 is clamped to the pinch and is adapted to attract a conical armature to which anodes 67 are secured through eyelets and metal studs surrounded by metal and insulating bushes. An auxiliary anode 64 is connected to a metal tube 62 which is surrounded by an insulating tube 63 and slidingly contacts with the leading- in wire 61. The tube 63 is rigidly secured through members 68 to the tubes 65 so that all the auxiliary anodes move together. A fullwave rectifying circuit, comprises two valves shown in Fig. 3 and a main secondary winding 83, Fig. 4, connected to the anodes 50. A secondary winding 84 is connected at its ends to the anodes 67 and a centre tapping thereon is connected through the magnet coils 78 to the cathode. An auxiliary rectifier 88, energized by a winding 85, is connected in such manner that the magnet coils are energized when the electrode 64 is immersed in the cathode. All of the electrodes are lifted by the magnet and the auxiliary electrodes strike maintaining arcs, the discharge currents of which flow through the magnet coils to maintain the electrodes in their raised position. The voltage produced by the auxiliary rectifier need not be equal to the voltage necessary for striking the arc and the load thereon ceases when the electrode 64 is raised. In another form, maintaining anodes 111, Fig. 5, a starting incandescent cathode 108 and an auxiliary anode 105 are supported from the pinch by conductors mounted in insulating tubes and passing through a hollow main anode 94. An insulating disc 112 is housed within the main anode and is supported on the anode 105 through insulating tubes 113, 115 and the cylindrical metal, carbon or insulating screen 114 which dips into the mercury and is provided with discharge slots. The distance between the main anode and the container is less than the mean free path of the electrons to screen the joint from the discharge. A full-wave rectifying circuit embodying valves shown in Fig. 5 comprises a secondary winding 119, Fig. 6, connected to the main anodes, heater windings 122 for the cathodes and windings 121 connected to the auxiliary anodes through chokes 123. The auxiliary anodes 105 are connected through resistances 126 to the main anodes. The centre tappings on the heater windings are connected to the main cathodes through resistances across which are developed potentials which impose a negative bias on the screens 114 with respect to the incandescent cathodes 108 to form cathode spots on the mercury cathodes externally of the screens. A source of current may replace the resistances and a switch may be provided to disconnect, preferably automatically, the incandescent cathodes after ignition. Specification 192,673, [Class 39 (i)], is referred to.