Abstract:
A filtering module, for example a nanofiltration or reverse osmosis module, is made of membranes arranged in a stack with flat sheets of feed channel spacer and permeate carrier. The stack has packs formed of two membrane sheets sealed on four sides and enclosing a permeate carrier. The packs alternate with sheets of feed channel spacer through the thickness of the stack. One or more permeate-collecting pipes pass through the thickness of the stack. The sheets of feed channel spacer have seals along two sides and around the permeate-collecting pipes. A module is formed by placing one or more stacks in a pressure vessel with a seal between the stack and the pressure vessel at a downstream end of the stack.
Abstract:
A liquid pumping system includes at least two water cylinders that are each controlled by a hydraulic piston. A rotary valve controls the hydraulic pistons. The rotary valve has an inner unit that rotates within an outer unit. Slots provided between the inner and outer units control the duration, rate and direction of hydraulic fluid supply to the hydraulic piston. A liquid pumping process comprises distributing an initial flow of pressurized hydraulic fluid between the hydraulic cylinders. The hydraulic cylinders move through a cycle in a phased relationship to provide a constant sum of flow rates from the liquid pumps. In a water treating process, feed water is pumped through the membrane unit. Brine from the membrane unit is returned to each liquid pump while that liquid pump is feeding water to the membrane unit.
Abstract:
A roll-to-roll process and apparatus is disclosed for treatment of a membrane substrate. The apparatus and process processes the membrane substrate in a forward direction using one or more treatment solutions, and then processes the membrane substrate in a reverse direction using other treatment solutions. The treatment solutions used in the forward and reverse directions are preferably chosen so that the treatment sequence is the same in both directions. In this manner, the membrane substrate can accumulate reaction time by repeated processing in forward and reverse directions. t,?
Abstract:
Membranes are arranged in a stack with flat sheets of feed channel spacer and permeate carrier. Flat feed channels and permeate channels alternate through the thickness of the stack. Edges of the feed channels are sealed along the length of the stack. Edges of the permeate channels are sealed across the width of the stack. The stack may be more than 1.5 m long. Optionally, membranes may be sealed to each other without being folded. A filtration element comprises a stack and a shell. The shell has at least an inlet to the feed channels and a permeate outlet. Optionally, the element may be operated in a permeate side cross flow configuration. Parts of the stack may be pre-assembled, in some cases by an automated process. The filtration element may be used for reverse osmosis, forward osmosis, pressure retarded osmosis or nanofiltration.