GB583502A - An improved method of and apparatus for sealing metal to glass - Google Patents

Abstract

583,502. Metal-to-glass seals. BURROW, J. H., MacGREGOR, V. G., REDSTONE, R., and WRIGHT, C. S. July 27,1944. No. 14402. [Class 36] A method of making glass-to-metal seals, shown applied to a radio-valve, comprises heating the metal member to fuse the adjacent portion of the glass relative movement of the metal and glass (during fusion of the latter) being limited by a stop-device, the heating being localized to prevent softening of any previouslymade seal. Fig. 1 shows the assembly of a metal disc 1 between two glass tubes 3, 4 which are to be sealed together as at 14, 15, Fig. 2. The tubes 3, 4 are mounted in relatively-movable dies 5, 6 having a co-operating guide-pin 7. The disc 1 is heated, as by eddy currents or gas flames, and the approach of the dies is limited by the abutment of tungsten stop-pins 8, 9, carried by the die 6, with the under surface of the disc 1. Fig. 5 shows the arrangement for sealing a cap 16 to the upper end of the tube 3 the cap being forced down by the upper die into abutment with a stop-pin 20 mounted in the lower die. Fig. 8 shows the final stage in which a second metal disc 25 is sealed between the tube 4 and a third glass tube 26. In this operation, the cap 16 is held between spring-pressed pins 34, 37, the approach of the dies, on heating the disc 25, being limited by abutment of the disc 1 with pins 30, 31 projecting from the lower die. Specification 475,688 is referred to.