Abstract: In a capacitive deionization water desalination apparatus, the waterways of the cell are physically switchable between treatment-phase and purge-phase. In treatment-phase, the waterways conduct the flow of water thickness-wise, in-series, through the whole stack of electrodes and spacers. In purge-phase, the waterways conduct the flow of purge-water into the edges of the spacers, and along the spacers parallel to the plane of the spacers.

Abstract: A water treatment apparatus comprising a stack of circular electrodes with a central through hole, the electrodes are supplied with electricity so as to form anodes and cathodes in alternating intercalation. The anodes and cathodes so arranged to lie in such close-spaced parallel face to face relationship as to form a capacitive deionization cell. Water to be treated is passed from the outside of the stack, radially inward through between the electrodes into the central through hole and then axially out of the stack.

Abstract: In a capacitive deionization water desalination apparatus, the waterways of the cell are physically switchable between treatment-phase and purge-phase. In treatment-phase, the waterways conduct the flow of water thickness-wise, in-series, through the whole stack of electrodes and spacers. In purge-phase, the waterways conduct the flow of purge-water into the edges of the spacers, and along the spacers parallel to the plane of the spacers.

Abstract: The softener is based on a capacitive-deionization (CDI) cell, in which the hardness ions are extracted, and disposed of still intact, in concentrated form. The softener is combined with a chelate to inhibit precipitation, in the appliance, from the concentrated effluent. The chelate being citric acid, the acidity is effective to keep the hardness ions in solution. The purify and regenerate modes of operation of the softener can be timed to coincide with the washing and rinsing cycles of the appliance, whereby the presence of the softener does not affect the speed and performance of the appliance.

Abstract: The capacitive electrodes of the CDI cell are arranged to form a tube. Water to be treated flows through the tube-walls. The CDI electrodes are permeable, and form the tube-walls, whereby the flow passes through the thicknesses of the electrodes and of the spacers. The electrodes may be in the form of concentric tubes, or may be wrapped spirally.

Abstract: The electrodes of the described CDI cell are porous and permeable. The liquid to be deionized (e.g. salt water to be desalinated) flows through the electrodes. The electrodes are arranged in a stack, alternating anode/cathode, and water being treated passes through every electrode in the whole stack. For regeneration, the cells are connected (short-circuited) together, and the ions are dislodged mainly by flushing action. The through-flow arrangement can be realized in a number of different configurations.

Abstract: A water treatment apparatus comprising a stack of circular electrodes with a central through hole, the electrodes are supplied with electricity so as to form anodes and cathodes in alternating intercalation. The anodes and cathodes so arranged to lie in such close-spaced parallel face to face relationship as to form a capacitive deionization cell. Water to be treated is passed from the outside of the stack, radially inward through between the electrodes into the central through hole and then axially out of the stack.