GB591100A - Improvements in flameproof and similar industrial well-glass lighting fittings - Google Patents

Abstract

591,100. Electric light fittings. HOLOPHANE, Ltd., and ENGLISH, S. May 25, 1943, No. 8312. [Classes 75 (ii) and 75. (iv)] A flame-proof lighting fitting shown in Fig. 1 comprises a cast iron or brass connecting box 1, a conical casting 3 secured to the underside of the box 1, a well glass 8 secured by a ring 5 to the rim of the casting 3, and a diffusing glass screen 12 resting on the rim of the well glass and extending slightly below the filament of the lamp 7. The screen 12 is formed preferably on its outer surface with horizontal prismatic rings 13 which deflect downwardly light emitted at small angles below the horizontal to limit the intrinsic brilliance of the source. The well glass may be formed with vertical diffusing prisms 14. Cushioning material 11 may be interposed between the screen on the well glass which is cemented between the ring 5 and a backing ring 9. Fig. 2 shows another construction in which a prismatic or translucent glass reflector 15 rests on a shoulder 16 in the well glass 8. The well glass 8, reflector 15, holding ring 5 and backing ring 17 are attached to the housing 19 by a chain 20 by which they are supported when renewing the bulb 7. In another construction a reflector around the bulb is supported by a metal gallery carried by the conical housing. In a further construction, downwardly-reflecting prisms are formed on one side of the well glass and diffusing screens on the other, or the upper zone of the well glass is coated with a translucent enamel. All forms permit free air circulation in the fitting.