A mixed bed filter is used to finely polish demineralised water
A mixed bed filter polishes demineralised water from, for example, an EDI plant. In this way we can ensure that the last minerals and salts are removed from the water.
The filter contains a mixture of two resins that act as cation and anion exchangers (attracting positive and negative ions respectively). As a rule, a mixed bed filter is not regenerable, so resin renewal is done either by replacing the resin alone or by replacing the complete filter (typically done during a scheduled service).