In a gas separation process a pressurized gaseous mixture is passed through a first bed of adsorbent while a second bed is being regenerated by desorbing gas therefrom and venting or discharging such gas from the second bed. The adsorbent is of such a character that one component of the gaseous mixture is preferentially adsorbed. The non-adsorbed component or components are collected as product. After a chosen time flow of gas into the first bed and out of the second bed is stopped, and the two beds are placed in communication with one another through a flow restrictor means so as to reduce the pressure difference therebetween. The flow restriction means is effective to prevent fluidization of the beds. The intercommunication between the two beds is stopped before the pressure difference therebetween has been eliminated and the gas mixture is then passed through the second bed, while the first is regenerated. The pressure difference between the two beds is then reduced and the cycle of operations repeated.