After regeneration has been accompanied by the removal of moisture as well as of heat from the drying medium bed, the system is brought to an identical pressure level before switching over from vessel A to vessel B. The exhaust valve, through which the regeneration and cooling air is expelled closes, so that the build-up of pressure can begin. Only after successful pressure equalisation via the regeneration duct can the dryer system be switched over from regeneration to adsorption. Pressure build-up takes a few minutes only.
