Superpermeability of solid membranes and gas evacuation Part II Permeation of hydrogen through a palladium membrane under different gas and membrane boundary conditions

Abstract

The permeation of atomized hydrogen through palladium membranes has been studied in view of its application for hydrogen pumping and recuperation. The atom permeation probability for a single impact with a membrane is measured by an atomic beam experiment in high vacuum and is found to be 0.1–0.2 practically independent of atomic hydrogen pressure, membrane thickness, temperature and boundary conditions in the wide ranges investigated. Thus, the membrane appears to be only a few times less permeable for atomic hydrogen than an opening in a thin wall and so a very large rate of hydrogen evacuation can be achieved. This is true in particular for ‘non-active’ palladium membranes, which have low permeability for molecular hydrogen and consequently can compress the gas by a factor of some orders of magnitude. Experimental results agree with the theory considered in Part I * of the present paper. Two † variants of pump construction are described capable of hydrogen evacuation followed by purification, compression and recuperation if required. The operation of these pumps is studied under different conditions. Both pumps described include the incandescent filament as a hydrogen atomizer, whose capacity limits the pumping speed. The utilization of the developed effect seems, however, to be most promising in cases where atomization is available by itself, for example, in thermonuclear fusion reactors.