An adsorbent fractionator directional flow control valve assembly includes two inlet valves, two exhaust valves, and a valve body. The valve assembly controls the directional flow of an influent gas mixture into one of two vertical desiccant tanks of an adsorbent fractionator, or desiccant dryer, and an effluent gas flowing in reverse through the opposite desiccant tank. The valve body is a single unitary piece, which may be a casting, and couples the inlet valves and the exhaust valves, which may be four identical valve subassemblies, providing flow communication between these and an inlet port, two exit ports, and an exhaust port. |