PROCESS AND APPARATUS FOR GAS FILLING AND CLOSING A GAS-TIGHT ENVELOPE FOR AN ELECTRIC LAMP ARC WELDING TORCH WEAVING METHOD

摘要

1460856 Discharge lamps ITT INDUSTRIES Inc 21 March 1974 [29 March 1973] 12538/74 Heading H1D [Also in Division B3] In a method and apparatus for filling a gasdischarge tube envelope 1, which is made of alumina and welded to metal end tubes 2, 2SP1/SP with narrow openings 3, 3SP1/SP, is enclosed in an enclosure 5 having an outlet 7 and an inlet 6. Solid substances 4 required for the discharge, e.g. mercury or sodium, are initially placed in envelope 1. With inlet 6 closed, air is pumped out by way of outlet 7, which is then closed, and inlet 6 is opened to admit gas, e.g. argon or Xenon, to the enclosure 5 and envelope 1. Two electrodes 10, 10SP1/SP aligned with the tubes 2, 2SP1/SP and the axis of envelope 1 are mounted in the walls of enclosure 5. Arcs are struck between the electrodes and the respective tubes 2, 2SP1/SP alternately as controlled by a change-over switch 15, for times determined by a timeswitch 12, to seal the metal tubes. Pieces of metal 9, 91 may be placed in tubes 2, 2SP1/SP, and the tubes may be of niobium and the pieces of metal of zirconium, the metals forming a sealing alloy. In a modification (Fig. 3, not shown), only one end of the envelope 1 is contained in an enclosure (51).