Abstract: An electric dust separator, adapted to remove solid or liquid particles from a gas stream, comprises a separating space defined by two coaxial cylindrical walls. The gas stream to be purified flows through the separating space in a helical path. Dipole charges are induced in the particles to be removed by means of a radial electric field which is too weak to cause a substantial ionization of the gas. The electrodes generating the field are shaped and arranged in such manner that the field intensity increases from the inside to the outside, and that the field is locally concentrated at the outer wall, but homogeneous at the inner wall. The particles are agglomerated and move downwardly along the outer wall. There is only a slight adherence of particles to the outer wall. The helical flow of the gas stream is obtained either by tangentially introducing the stream in the separating space, or by a rotation of the separating space.