An air cleaner includes a flying body having a main body unit in which a control unit controlling flying movement is stored, and a propeller disposed around the main body as propulsion for floating the flying body; and a dust collector connected to the flying body, and including an intake opening and an exhaust opening. The propeller is disposed inside or under the dust collector, the dust collector electrostatically attracts dust in air flowing from the intake opening, and the flying body is a drone structured so that the propeller takes in air from an upper side and exhausts the air to a lower side.

Provided are an apparatus and a system for classifying particles. The apparatus for classifying particles includes: an internal electrode which has a column shape; an external electrode which is spaced apart from the internal electrode and disposed to surround the internal electrode, and generates an electric field through an interaction with the internal electrode; and an aerosol supply unit which supplies aerosol particles to a separation space between the internal electrode and the external electrode, in which the separation space, through which the aerosol particles are introduced into the particle classifying apparatus and flow, is formed to be narrowed toward a lower aerosol flow side from an upper aerosol flow side into which the aerosol particles are introduced.

Provided are an apparatus and a system for classifying particles. The apparatus for classifying particles includes: an internal electrode which has a column shape; an external electrode which is spaced apart from the internal electrode and disposed to surround the internal electrode, and generates an electric field through an interaction with the internal electrode; and an aerosol supply unit which supplies aerosol particles to a separation space between the internal electrode and the external electrode, in which the separation space, through which the aerosol particles are introduced into the particle classifying apparatus and flow, is formed to be narrowed toward a lower aerosol flow side from an upper aerosol flow side into which the aerosol particles are introduced.

A charging device or an electric dust collector has a downstream side grounded electrode plate 90 placed so as to obstruct the flow of a dust-containing air and having openings 91 for allowing the dust-containing air to pass therethrough, a supporting plate 60 placed on the upstream side of the electrode plate 90, and downstream side discharging electrodes 80b supported by the supporting plate 60 so as to extend from the supporting plate 60 towards the electrode plate 90, and placed so as to correspond to the openings 91. The tip parts of the discharging electrodes 80b penetrate the openings 91 and project to the downstream side of the electrode plate 90, and the tip part of each discharging electrode 80b and the edge part of each opening 91 are positioned so as to have a predetermined gap between them.

A charging device or an electric dust collector has a downstream side grounded electrode plate 90 placed so as to obstruct the flow of a dust-containing air and having openings 91 for allowing the dust-containing air to pass therethrough, a supporting plate 60 placed on the upstream side of the electrode plate 90, and downstream side discharging electrodes 80b supported by the supporting plate 60 so as to extend from the supporting plate 60 towards the electrode plate 90, and placed so as to correspond to the openings 91. The tip parts of the discharging electrodes 80b penetrate the openings 91 and project to the downstream side of the electrode plate 90, and the tip part of each discharging electrode 80b and the edge part of each opening 91 are positioned so as to have a predetermined gap between them.

An electrification apparatus for an electrostatic dust collector, including: a first electrode part having a shape of a plate having a plurality of through holes formed thereon in such a manner as to apply one of positive and negative electrodes thereto; and a second electrode part having protrusions each having a plurality of fine conductive fibers in such a manner as to protrude outwardly from the through holes of the first electrode part, whereby electrification performance is improved and harmful ozone and electromagnetic waves are reduced.

An electrification apparatus for an electrostatic dust collector, including: a first electrode part having a shape of a plate having a plurality of through holes formed thereon in such a manner as to apply one of positive and negative electrodes thereto; and a second electrode part having protrusions each having a plurality of fine conductive fibers in such a manner as to protrude outwardly from the through holes of the first electrode part, whereby electrification performance is improved and harmful ozone and electromagnetic waves are reduced.

An air freshener is disclosed. The air freshener includes a body case defining the air freshener, the body case having a filter installation opening formed in one side thereof, a filter housing disposed in the body case, the filter housing having a power terminal disposed therein, a drawer configured to be withdrawn from the inner space of the filter housing through the filter installation opening, and an electric dust collector separably located in the drawer, the electric dust collector having a power-receiving terminal disposed therein, wherein the power terminal contacts the power-receiving terminal in the state in which the drawer is settled in the inner space of the filter housing.

An air freshener is disclosed. The air freshener includes a body case defining the air freshener, the body case having a filter installation opening formed in one side thereof, a filter housing disposed in the body case, the filter housing having a power terminal disposed therein, a drawer configured to be withdrawn from the inner space of the filter housing through the filter installation opening, and an electric dust collector separably located in the drawer, the electric dust collector having a power-receiving terminal disposed therein, wherein the power terminal contacts the power-receiving terminal in the state in which the drawer is settled in the inner space of the filter housing.

A dust collection assembly (100) comprises a first annular ring (110) and a second annular ring (120). The first annular ring (110) is provided with a first electrical connection member (113) for connection to either the positive pole or the negative pole of a power source; the second annular ring (120) is disposed both separatedly from and insulatedly from the first annular ring (110); the second annular ring (120) is provided with a second electrical connection member (123) for connection to the other of the positive or negative poles of the power source. Also disclosed are an air purification device and an air conditioner comprising the present dust collection assembly (100).