Regenerating drying system

Claim 1

In a system for drying air: a. a source of air to be dried; b. a pair of vessels containing desiccant material past which air must move in the drying of same; c. said vessels being alternately connected in a drying step between said source and a discharge point for dried air; d. one of said vessels having the desiccant material therein being regenerated while the desiccant material of the other of said vessels is removing moisture from air supplied at said source; A. said vessels being arranged so that the flow of air through the other vessel connected for removing moisture therefrom is in one direction, while B. said one vessel having the desiccant material therein being regenerated having the flow of regenerating air in the opposite direction from the flow of air in the other vessel; e. circuit means for connecting said vessels alternately for drying and regeneration by flow therethrough in said opposite directions comprising; f. a bypass circuit connected between said source and the connection of said source to the vessel in said drying step and bypassing a part of the air from said source; g. a heater in said bypass circuit for heating said bypass air before being diverted to said one vessel; h. additional circuit means for connecting said one vessel to the other vessel with heated bypass air which has regenerated the desiccant therein; i. a cooling circuit connected in shunt with said by pass circuit and having a cooler connected therein including means for directing cooler air in an opposite direction through the desiccant of said one vessel to cool the desiccant therein after the desiccant has been regenerated.