Patent ID: 8448479

Claim:
An ion elution unit that generates metal ions from electrodes when a drive circuit applies a voltage between the electrodes, the ion elution unit comprising: a water feed valve for feeding water to the ion elution unit; and a control unit configured to control the drive circuit when the water feed valve is feeding water to the ion elution unit to firstly apply the voltage between the electrodes by applying a positive voltage potential to a first electrode during a first adjustable voltage application period to cause the first electrode to act as an anode relative to a second electrode acting as a cathode so that the first electrode will provide the metal ions during the first adjustable voltage activating period, to secondly apply no voltage difference between the first and second electrodes during an adjustable voltage application halt period, and thirdly to apply the positive voltage to the second electrode during a second adjustable voltage application period to cause the second electrode to act as the anode relative to the first electrode acting as the cathode so that the second electrode will provide the metal ions during the second voltage activating period, the control unit being further configured to adjust at least one of the length of the first adjustable voltage application period, the length of the adjustable voltage application halt period, the length of the second adjustable voltage application period, and the length of an overall ion elution period that includes at least the first adjustable voltage application period, the adjustable voltage application halt period, and the second adjustable voltage application period to adjust the amount of eluted metal ions being produced to a desired level, wherein the electrodes are disposed along water current fed, wherein metal ion eluted from the electrodes are either silver ions, copper ions, or zinc ions, and wherein the control unit is further configured to control the drive circuit to adjust the voltage applied to the electrodes during at least one of the first adjustable voltage application period and the second adjustable voltage application period such that a constant current flow between the electrodes can be maintained.