Atomization in a Static System

A steady flow of hydrogen was established over the unheated filament at a pressure, pg, which was determined by the rate gas entered the reaction cell and the rate gas was removed by pumping due to the ionization gauge, the walls, and the port. When the temperature of the filament was raised rapidly to a value in the range 1100-1500°K, the pressure in the cell fell to a value P, which remained steady for about 30 sec before it began to increase. The new pressure P remained constant as long as the glass walls of the reaction cell, which were kept at 

There are two main corrections which have to be made to observed parameters in both static and flow systems. First, if the pressure gauge is at a temperature different from that of the reaction vessel, allowance must be made for thermal transpiration 14). Second, if a heated filament is in a steady state, there will be a temperature gradient at the ends where it is attached to heavier gauge supports, and, especially for short filaments, the necessary correction (25) can be quite large. 

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