| 摘要 |
502,585. Metal-vapour lamps. GENERAL ELECTRIC CO., Ltd. (Patent- Treuhand-Ges. f³r Elektrische Gl³hlampen) March 9, 1938, No. 7388. [Class 39 (i)] [Also in Group XXXV] A number of high-pressure metal vapour lamps and an incandescent filament are contained in a common envelope, one terminal of each of the lamps and one terminal of the incandescent filament being all connected together and the other terminal of the filament and the lamps being separated from each other, so that the lamps can be supplied with alternating currents displaced in phase relatively to one another, all of which pass through the filament. The common envelope may be coated with phosphorescent material excited by the radiation from the lamps. An arrangement is shown in Fig. 1 comprising an outer envelope 2, coated with phosphorescent material 3 and containing two high-pressure metal vapour lamps 4, 5 inclined in opposite directions at 45‹ to the axis of the envelope and a tungsten filament 6 lying in the axis thereof. The lamps have thermionic electrodes 7 heated by the discharge and starting electrodes 8. The lower end 11 of the filament and the two lower electrodes 7 of the lamps are connected together, while the other electrodes and the other terminal of the filament are connected to separate contacts 10, 12, 13. Fig. 2 shows a circuit arrangement in which the filament contact 10 is connected directly to one terminal of the A.C. supply, the contact 12 of one lamp to the other terminal of the supply through a choke 15 and the contact 13 to the same supply terminal through a condenser 16 and choke 17. The contacts 10 and 12 may be connected through a condenser 18. The impedance of the choke 17 is preferably less, but only slightly less, than the impedance of the condenser 16, and 'the condenser 18 is so adjusted that the discharge through the lamps 4 and 5 are approximately equal. In a modification, the choke 17 may be formed as part of the choke 15. The discharge lamps may have a common discharge envelope. |
