Abstract: A process vessel (2) is for achieving contact between at least one fluid passing through the vessel (2) and a packing material contained therein. The process vessel (2) has a peripheral wall (8) disposed around a longitudinal axis, an inlet for permitting entry of fluid into the vessel and an outlet for permitting the exit of fluid from the vessel. A redistributor (4) is located within the vessel (2) and the redistributor (4) follows a locus (3) which extends around the inside surface (10) of the peripheral wall (8). The locus (3) is neither perpendicular or parallel to the longitudinal axis and is preferably spiral or helical.