GB452128A - Improvements in or relating to electric incandescent lamps - Google Patents

Abstract

452,128. Electric incandescent lamps with residual gases. ALEXANDER, P., and JANOSKA, G., 93, Rue Elise, Brussels. Nov. 9, 1934, No. 32353. Void [Abridged as open to inspection under Sect. 91 of the Acts, May 14, 1935]. [Class 39 (ii)] The bulb of an electric incandescent lamp contains, in addition to the current carrying incandescent body, a catalyst and a carbon compound which, in a cyclic process, is dissociated by the heat of the incandescent body into gaseous substances which combine on the catalyst with the accompaniment of luminous phenomena. In the example the bulb contains carbon monoxide, and the catalyst consists of the oxides of the rare earth metals, such as a mixture of thorium oxide and cerium oxide. At the operating temperature of the incandescent body the carbon monoxide is dissociated into its constituents, which at the surface of the heated catalyst combine, to form carbon monoxide. The catalyst may be supported upon a cylindrical grid or network surrounding the incandescent body and as near to the latter as is necessary for the catalyst to become heated to the temperature at which the catalytic effect occurs. Preferably the incandescent body, catalyst, and a filling of carbon-monoxide are enclosed in a hermetically sealed infusible transparent container which is enclosed within an evacuated lamp bulb of the usual type. In order to diminish the quantity of heat lost by the lamp, a selective filter, consisting in known manner of one or more layers of metal such as silver, may be provided in the path of radiation, whereby incident rays of long wave length, particularly the heat rays, are reflected back, while the rays of short wave length, particularly the light rays are transmitted. Preferably the filter is so shaped and arranged that the reflected heat is directed largely upon the catalyst, or upon the incandescent body. The filter may be arranged either on a separate supporting body surrounding the incandescent body, or directly on the wall of the container enclosing the incandescent body and catalyst. Alternatively the filter may be provided on the outer bulb. The catalyst may be provided directly on the incandescent body.