Water softening device and method of operating a water softening device

Abstract

A water softening device includes a filter configured to remove hardness from a first stream of raw water to produce a second stream of softened water. The filter includes an ion exchange material which is loaded with a first cationic ion species deriving from a tracer salt and with a second cationic ion species deriving from a regenerant salt. The IEX material shows a lower affinity to the first cationic ion species than to the hardness. At the same time the IEX material shows a higher affinity to the first cationic ion species than to the second cationic species. An electrical property of the second stream is monitored by a sensor. A change in the monitored electrical property can be used as an indicator for the exhaustion state of the filter.

Dependencies are inferred from the claim text.