Patent ID: 7850768

Claim:
An air filtering apparatus for electrolyzing water in an electrolytic bath by applying a voltage between electrodes in the electrolytic bath, supplying the generated electrolytic water to a gas-liquid contact member and blowing air to the gas-liquid contact member to filter the air, comprising: a scale removing unit for inverting the polarities of the electrodes to remove scale deposited on the electrodes; a judging unit for judging on the basis of a current value flowing between the electrodes whether the scale is removed from the surface of the electrode; a bypass passage through which electrolytic water flowing out from the electrolytic bath bypasses the gas-liquid contact member; a bypass valve for prohibiting the electrolytic water containing the scale from being supplied to the gas-liquid contact member and guiding the electrolytic water to the bypass passage; and a controller being operative to close the bypass valve when the polarities of the electrodes are inverted, and to open the bypass valve in response to the judging unit judges that the scale is removed from the surface of the electrode.