Abstract

A new method of Trapping oil Vappor back diffusing from the fine side jet of an oil diffusion pump, formarly proposed with some experimental results, was applied to three stage specially designed fractionating pump.
The ultimate vacuum of 7.4×10^-6mm Hg was reduced to 1.4×10^-6mm Hg by using the trap. More effect of the trap is expected by introducing an other oil suitable for the purpose.