Abstract: Two different conversion modes are used for determining the water hardness from the conductivity of raw water in a water softening device dividing an influent raw water volume flow into two partial volume flows and subjecting a partial volume flow to a full softening process and re-uniting the two partial volume flows thereafter again into an admixed water volume flow. A first calibration curve reflects the maximum water hardnesses occurring at different conductivities; it is used for automatically controlling the regeneration of an ion exchange resin. A second calibration curve reflects the average water hardnesses at different conductivities; it is used for controlling the ratios of the two partial volume flows in the admixed water. With the invention, variations in the correlations between conductivity and water hardness may be taken into account in order to optimize regeneration and to minimize the hardness tolerances of admixed water.

Abstract: A control unit for a softening device, comprising a primary inlet for untreated water, a primary outlet for blended water, a sensor for determining the water hardness of the untreated water WHraw, or the blended water WHblend, a secondary outlet, a secondary inlet, a bypass line, a blending means which can be automatically adjusted for mixing a blended water flow Vblend(t) from a first partial flow (V(t)part1soft of the secondary inlet and a second partial flow V(t)part2raw of the bypass line, and an electronic control means, wherein the control means is designed to readjust the adjustment position of the blending means by means of the determined water hardness in such a fashion that the water hardness in the blended water flow Vblend(t) is adjusted to a predetermined desired value, enables partial softening of water on the basis of fully automatic blending, thereby utilizing already existing softening devices.

Abstract: A method for operating a water softening system (1) comprising an automatically adjustable blending means for mixing a blended water flow V(t)blended from a first, softened partial flow V(t)part1soft and a second untreated water partial flow V(t)part2raw and comprising an electronic control means (11), wherein the control means (11) readjusts the adjustment position of the blending means by means of one or more experimentally determined instantaneous measured values in such a fashion that the water hardness in the blended water flow V(t)blended is adjusted to a predetermined desired value (SW), is characterized in that the control means (11) ignores at least one of the one or more instantaneous measured values for readjustment of the adjustment position of the blending means in one or more defined operating situations, and instead uses the respectively last corresponding measured value that was valid prior to occurrence of the defined operating situation, or a standard value for the corresponding measur

Abstract: A method for operating a water softening system (1) comprising an automatically adjustable blending means for mixing a blended water flow V(t)blended from a first, softened partial flow V(t)part1soft and a second untreated water partial flow V(t)part2raw and comprising an electronic control means (11), wherein the control means (11) readjusts the adjustment position of the blending means by means of one or more experimentally determined instantaneous measured values in such a fashion that the water hardness in the blended water flow V(t)blended is adjusted to a predetermined desired value (SW), is characterized in that the control means (11) ignores at least one of the one or more instantaneous measured values for readjustment of the adjustment position of the blending means in one or more defined operating situations, and instead uses the respectively last corresponding measured value that was valid prior to occurrence of the defined operating situation, or a standard value for the corresponding measur

Abstract: A control unit (1, 1a) for a softening device (2), comprising a primary inlet (4) for untreated water, a primary outlet (7) for blended water, a sensor for determining the water hardness of the untreated water WHraw or the blended water WHblend, a secondary outlet (5), a secondary inlet (6), a bypass line (9), a blending means which can be automatically adjusted for mixing a blended water flow Vblend(t) from a first partial flow (V(t)part1soft of the secondary inlet (6) and a second partial flow V(t)part2raw of the bypass line (9), and an electronic control means (11, 11a), wherein the control means (11, 11a) is designed to readjust the adjustment position of the blending means by means of the determined water hardness in such a fashion that the water hardness in the blended water flow Vblend(t) is adjusted to a predetermined desired value, is characterized in that the control unit (1, 1a) is designed in the form of an external control unit (1, 1a) for the softening device (2), wherein the control unit (1, 1a

Abstract: In summary, the invention proposes to provide two different conversion modes for determining the water hardness on the basis of the conductivity of raw water in a water softening device (1) dividing influent raw water volume flow V(t)raw into two partial volume flows V(t)partial1soft V(t)partial2raw, subjecting a partial volume flow V(t)partial1soft to a full softening process and re-uniting the two partial volume flows thereafter again into an admixed water volume flow V(t)admixed. Conversion using a first calibration curve (F1) is conservative and reflects the maximum water hardnesses occurring at different conductivities; this conversion mode is used for automatically controlling the regeneration of an ion exchange resin (5), with the capacity of the ion exchange resin being known. The conversion using a second calibration curve (F2) is close to reality and reflects the average water hardnesses (i.e.