Charging device and electric dust collector

A charging device for charging particles such as dust, mist or the like in dust-containing air by using corona discharge generated by applying a high voltage, comprising:

• a downstream side grounded electrode plate which is placed so as to obstruct a flow of the dust-containing air and has a plurality of openings for allowing the dust-containing air to pass therethrough;
• an upstream side grounded electrode plate which is placed on an upstream side of the downstream side grounded electrode plate in the direction of the flow of the dust-containing air so as to obstruct the flow of the dust-containing air, and has a plurality of openings for allowing the dust-containing air to pass therethrough;
• a supporting plate which is placed between the downstream side grounded electrode plate and the upstream side grounded electrode plate;
• a plurality of downstream side discharging electrodes which are supported by the supporting plate so as to extend from the supporting plate towards the downstream side grounded electrode plate, and placed so as to correspond to the plurality of openings of the downstream side grounded electrode plate respectively;
• and
• a plurality of upstream side discharging electrodes which are supported by the supporting plate so as to extend from the supporting plate towards the upstream side grounded electrode plate, and placed so as to correspond to the plurality of openings of the upstream side grounded electrode plate respectively,
• wherein tip parts of the plurality of downstream side discharging electrodes penetrate the plurality of openings of the downstream side grounded electrode plate respectively and project to a downstream side of the downstream side grounded electrode plate in the direction of the flow of the dust-containing air, each of the tip parts of the plurality of downstream side discharging electrodes and each of edge parts of the plurality of openings of the downstream side grounded electrode plate are positioned so as to have a predetermined gap between them, tip parts of the plurality of upstream side discharging electrodes are positioned on a downstream side of the upstream side grounded electrode plate in the direction of the flow of the dust-containing air, and each of the tip parts of the plurality of upstream side discharging electrodes and each of edge parts of the plurality of openings of the upstream side grounded electrode plate are positioned so as to have a predetermined gap between them.