GB360889A - Improved manufacture of electric glow lamps - Google Patents

Abstract

360,889. Electric incandescent lamps. SUNDBERG, H. E., 36, Valhallavagen, Stockholm. May 9, 1930, No. 14376. Convention date, May 10, 1929. Void [Published under Sect. 91 of the Acts]. [Class 39 (ii).] An electric incandescent lamp is provided with an internal glower which is highly absorbent of heat rays and receives heat reflected from the walls of the. bulb. A portion only of the wall is permeable to light, the remainder of the bulb being made substantially reflective of all rays, while the part that is permeable to light is adapted to retain heat and to form a filter to pass only rays of short wave length. The filter may be arranged as a grating consisting of an accumulation of particles of precious metals, copper, nickel, iron, &c. The walls of the bulb may be frosted externally or internally, and a reflecting portion thereof may consist of a metallic coating obtained by thermal decomposition or chemical reduction of suitable materials. A glower for use in the lamp may be obtained by electrically heating a tungsten wire and passing it through a heat absorbing substance such as an oxide, carbide, nitride, &c. of a rare element. Preferably the metallic filter is protected by a thin coating of glass, water glass, &c.