The calculation of the shadow factor of single coil filament
A computer method for calculating the power-reduction factor of a single-coil filament is presented. The filament of incandescent lamps is coiled, which is why a fraction of radiation is trapped in the filament. The relationships between the geometric parameters of a cylindrical helix (pitch ratio and mandrel ratio) and the shadow factor are developed. A FORTRAN program based on the numerical solution of algebraic equations and on three-dimensional numerical integration has been developed.<<ETX>>
Calculation of the performance parameters of tungsten filament lamps using the exponent rules
The experimentally known values of the 14 exponents associated with the exponent-rules for vacuum and gas-filled tungsten filament lamps are utilized to obtain the temperature dependence of performance parameters such as power demand, lumen output, life and efficacy. It is also shown that the data on emissivity of tungsten reported by Jones and Langmuir are consistent with theory in contrast to those obtained by Roser and Wensel. Further, the analysis predicts a higher power loss factor and a longer life for gas-filled tungsten filament lamps than for vacuum lamps.
Calculation of the radial tungsten transport in cylindrical gas-filled incandescent lamps
The rate of tungsten transport in a cylindrical gas-filled incandescent lamp has been calculated. The theory is based on the assumptions of Langmuir and Fonda. In this model the transport has been determined by the rate of diffusion through the stationary Langmuir zone. The diameter of that zone has been calculated according to the method of Elenbaas. In the present method the position dependence of the diffusion coefficient is introduced. A result is that the rate of tungsten transport as a function of the envelope diameter has a minimum. The inner envelope diameter is then equal to that of the Langmuir zone. The theory gives also an easy method of calculating the working pressure of the inert gas from the filling pressure.