Depletion compartment and spacer construction for electrodeionization apparatus

DETAILED DESCRIPTION The present invention provides a spacer for a depleting compartment of an electrodeionization apparatus which promotes even distribution of liquid through the compartment.
The spacer comprises a shaped element with a liquid inlet means which includes a manifold having a base and projections extending from the base and a plurality of channels.
The inlet means is in fluid communication with a primary manifold and an open central section of the spacer.
The projections promote uniform flow from the primary manifold through the channels.
The central section of the ion depletion compartment includes ribs extending the length of the central section which divide the central section into subcompartments.
The ion exchange resin beads within the subcompartments are retained in the subcompartments by bonding or physically restraining the cationic permeable membrane to one surface of the depleting compartments and to the ribs and bonding or physically restraining the anionic permeable membrane to the opposing surface of the depleting compartment to the ribs, thereby to define the subcompartments.
The concentrating compartments into which ions migrate from the depleting compartments are free of ion exchange beads.
The electrodeionization apparatus can comprise a single stage or a plurality of stages in series wherein the process voltage can be controlled independently in each stage, if desired.