Abstract: A banked purification system having, in flow series, an inlet for entry of a fluid, a bank of two or more purification columns in which the fluid is purified by a purifying component, and an outlet for discharging the purified fluid, the columns being arranged in parallel such that the fluid from the inlet splits at first ends of the columns into respective streams which flow through the columns and recombine at second ends of the columns for onward travel to the outlet; wherein the columns have first ports in the side walls of the columns at the first ends, the first ports being connected to each other such that the first ends are placed in fluid communication to create a manifold from the first ends of the columns which splits the fluid from the inlet into said streams.

Abstract: An electronic device is disclosed for controlling gas flow in a gas dryer such as a twin tower regenerative gas dryer. The device has a housing in which is mounted an electronic control circuit. At least two electrically operated valves (e.g. solenoid valves) for controlling functions of the dryer are provided with plugs or sockets and adapted to co-operate with corresponding sockets or plugs in a wall of the housing electrically connected to the electronic circuit. The valves are mounted on, externally of, the housing and are electrically connected to the control circuit.