Electrostatic filter

Claim 1

An electrostatic filter for separating solid particles or liquid particles or a combination of both suspended in air, comprising: an electrically conducting, elongate separation tube having air-inlet openings distributed over the surface thereof, said separation tube being open at one end and closed at the other end by an end wall, at least one elongate electrode positioned within said separation tube in spaced relation thereto, a high-voltage direct current source connected across said separation tube and said at least one elongate electrode to produce an electric charge current from said electrode to said separation tube, a layer of air-permeable material on the outer surface of said separation tube covering all of said air-inlet openings, a housing having an air-intake opening at one end thereof and an air-outlet opening at the other end thereof, said separation tube being supported within said housing by sealing means transversely dividing the interior of said housing into a suction chamber and a separation chamber with the open end of said separation tube communicating with the suction chamber having the air-outlet opening and the remainder of said separation tube projecting into the separation chamber having the air-intake opening, and suction means connected to the air-outlet opening of said housing for drawing air into said separation tube through said layer of air-permeable material and said air-inlet openings, said layer of air-permeable material being dimensioned and said air-inlet openings being dimensioned and spaced over the surface of said separation tube to provide an air resistance such that substantially the same pressure drop of the air passing through said layer and said air-inlet openings to the interior of said separation tube along the whole of the length of said separation tube covered by said layer is created.