Adsorbent fractionator with automatic cycle control and process

Claim 1

1 . Apparatus having a sorbent bed for alternately adsorbing and thereby reducing the concentration of first gas in a mixture thereof with a second gas to below a limiting maximum concentration thereof in the second gas and then regenerating the sorbed bed by desorption of adsorbed first gas without application of heat, a vessel (1, 2) being provided,a chamber therein for a bed (10, 10) of sorbent having a preferential adsorptivity for the first gas and that is regenerated by desorption of first gas without application of heat; a line (3, 4) for delivering influent gas at an inlet end of said bed; a line (7, 8) for delivering effluent gas from an outlet end of said bed; a capacitor (20, 21) having two conductors of selected surface area spaced from each other a sufficient distance to define a space sized to accommodate a volume of sorbent as the dielectric whose change in first gas content, detected as a function of dielectric constant, causes a change in capacitance thereof and means responsive to the change in capacitance to give a signal being provided, characterized by the capacitor.(20 21) being positioned in the bed (10, 10) to said means giving a signal when a selected capacitance indicating a selected first gas content slightly lower than that corresponding to regeneration is reached or exceeded so that if a fully regenerated bed were switched onstream under nonsorbing conditions, there would be no regeneration when it entered the regeneration cycle; and means for halting the regeneration in response to the signal, even if the drying cycle continues, thereby ensuring that any purge flow and energy used in regeneration of the bed will not be wasted.