GB646026A - Improvements in and relating to evacuating apparatus - Google Patents

Abstract

646,026. Making electric lamps. BRITISH THOMSON-HOUSTON CO., Ltd. Feb. 7, 1947, No. 3724. Convention date, Feb. 7, 1946. [Class 39 (ii)] [Also in Group XL(a)] An electric discharge lamp evacuating and filling apparatus comprises a plurality of conduits 47 having means e.g., a solenoid valve 52 and a pump (not shown) for maintaining a rough vacuum therein and a movable assembly e.g., an indexible turntable 1 including a fine vacuum pump 3, a support 22 for a lamp 27 connected to the pump inlet and a solenoid valve 14 between the pump 3 and the lamp 27 and complementary ports 43, 45 on the table 1 and a support 2 for connecting the higher pressure side of the pump 3 with a different one of the conduits 47 in each of a plurality of positions of the table 1. Sixteen stations are mounted on a peripheral flanges 5 and each comprises a pump 3, valve 14, support 22 and lamp 27 and at one of the stations viz., that shown, is provided a xenon, argon or hydrogen gas duct and a solenoid valve 54 energized by a mercury switch 56 responsive to pressure within the duct 47 and hence of the lamp 27, assuming valve 14 to be open. In operation closing of a manual switch 65 supplies power through slip rings 63, 64 and lines 66, 67 to the condenser pump heating elements and through a cam switch 69 to the solenoid of the switch 14. The switch 69 when closed corresponds to the open position of the valve 14 in all but the one position of the table 1 at which the lamps 27 are loaded. With a switch 72 in the L.H. position the valve 52 is open and the valve 54 closed to roughly evacuate the particular system in register. On moving the switch 72 to the R.H. position the valve 54 is opened when the pressure in the duct 47 is reduced enough to close the mercury switch 56 whereupon gas floods the pump 3 and the lamp 27; the consequent rise in pressure then effecting closure of the valve 54. As the table indexes to the next position the cam switch 69 opens to close the valve 14 thus shutting off the inlet side of the pump 3 whilst the lamp is being sealed, removed and a new one loaded. The pressure to which the lamp 27 is filled is varied by the setting of the switch 56.