GB313727A - Improvements in or relating to electric discharge devices for producing ultra violetradiation - Google Patents

Abstract

313,727. Freedman, P. May 22, 1928. Low - pressure metallic - vapour apparatus; vacuum tubes.-In discharge lamps for producing ultra-violet radiation and either of the kind having a mercury or other vaporizable electrode or in which the discharge passes through permanent gases only, the leads to the several electrodes are brought through one common stem in which the leading-in wires are sealed. The lamp shown in Fig. 1 has two mercury electrodes 10, 11, the leads being brought through a single stem 7. The lead to the electrode 11 is insulated from the mercury pool 10 by a glass tube 12 integral with the stem, and from the arc discharge by a chain of interfitting conical beads 13 of porcelain &c. Fig. 3 shows a lamp as described in Specification 313,726 with a modified starting- device, the auxiliary electrode of which consists of a metal chain or flexible conductor 32 kept in a fixed position with respect to the mercury pool by means of an insulating float 33. The lamp shown in Fig. 4 is started by an auxiliary discharge between pointed wires 44, 45 which is caused by resistances 46, 47 to be short-circuited when the main arc strikes. Fig. 5 shows a lamp similar to that shown in Fig. 1, but having a solid electrode at the sealed end. A similar lamp is described (Fig. 6, not shown) with solid electrodes at both ends. Some of the conductors or resistances may be operated at a high temperature as described in Specification 313,726.