Patent ID: 7488421

Claim:
Water processing method, by means of membrane distillation, wherein the water to be processed is held in a supply chamber, a wall of which is formed at least in part by a stack of membrane layers which are permeable to water vapor, said stack comprising a hydrophobic membrane and a hydrophilic membrane, wherein the hydrophilic membrane runs parallel to the hydrophobic membrane and is located on the side of the hydrophobic membrane that is remote from the water to be processed, the hydrophilic membrane has a greater thickness in comparison with the hydrophobic membrane, the hydrophilic membrane has a lower thermal conduction per unit area in comparison with the hydrophobic membrane, a vapor pressure difference between the water to be processed and condensed water is created by a pumping action so that the membrane distillation is driven by the vapor pressure difference resulting from the pumping action, the water condensing in the pores of the hydrophilic membrane, the water pressure difference is at least partially created by the fact that the condensed water is pumped out of the hydrophilic membrane by a micropump method including a force acting on the water molecules in the pores of the hydrophilic membrane, and wherein, in order to provide an electro-osmotic pump action, two flat electrodes are arranged in parallel with the hydrophilic membranes such that at least a layer of the hydrophilic membrane runs between the two electrodes.