GB534178A - Improvements in and relating to methods of making glass enclosures - Google Patents

Abstract

534,178. Making electric incandescent lamps. BRITISH THOMSON-HOUSTON CO., Ltd. Jan. 10, 1940, No. 523. Convention date, Jan. 12, 1939. [Class 39 (ii)] [Also in Group XXIII] In order to facilitate the sealing together of glass sections in definite relation with respect to one another to form an enclosure, particularly an electric lamp of the kind described in Specifications 515,091 and 526,924, the sections are formed with sealing-surfaces at the outer edges of their rims, and with co-operating surfaces which keep the parts in registry during the sealing-operation, the co-operating surfaces being separated after sealing to prevent the formation of strains in the seal. The two sections, 11, 12, Fig. 2, are provided with sealing surfaces 24, 25 respectively, and the section 12 is provided with an annular flange 30 which cooperates with a flat surface 29 on the section 11. The parts 29, 30 are spaced from the surfaces 24, 25 a sufficient distance to be unaffected by the heat of the sealing burners. When the sections are assembled, the rims are heated by pointed flames from a number of burners 34, the sections being rotated while being heated. As the glass softens, the section 12 descends by gravity until the flange 30 rests on the surface 29. When the seal is completed, and while the glass is still plastic, the sections are separated slightly, as shown in Fig. 3, to prevent strains from being set up in the seal. The separation may be effected by blowing a gas, preferably nitrogen. into the enclosure to lift the section 12 until it is arrested by a stop. The separation can be effected, also, by mechanical means such as by a suction cup gripping the outer surface of the section 12.