Improvements in Incandescent Electric Lamps of the 'Nernst' Type


17,282. Drake, B. M., Ram, G. S., and Nernst Electric Light, Ltd. Aug. 29. Incandescent lamps.-An incandescence body G of the Nernst type is placed in series with a steadying-resistance R, R', variable by hand or automatically to keep the current constant as the incandescence body becomes old, when the lamp is supplied at constant pressure. A part R of the resistance may be fixed, and consist of nickel. The variable part R<1> is adjusted until the fixed resistance R begins to show red in the dark. Several forms of the variable resistance R<1> are described. It may consist of nickel, platinum, or other wire wound on a porcelain insulator, a spring contact being movable along it by a screw with a milled head. Or the wire R<1> may be wound partly on a rotatable porcelain cylinder F, and partly on a parallel metal rod S, which may be turned by a milled head M in opposition to a spring acting on the cylinder F. Either of these arrangements may be turned automatically by electromagnetic means, instead of the milled head. In other forms, spring contacts are movable rectilineally along the resistance by a hot wire or a core and solenoid in opposition to a spring ; or a hot wire helix may have its coils closed together more or less by a hot wire or a core and solenoid, to vary its temperature and residtance ; or a hot wire sagged by a spring may be more or less short-circuited by contact with stationary curved metal strips.




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