Abstract: An electrostatic precipitator wherein a gaseous carrier medium is caused to pass through one or more electrostatic filters to be relieved of the major percentage of impurities. The thus purified carrier medium is caused to flow through a tapering funnel-shaped section of the outlet wherein the lower layer of the flow is caused to enter an elongated horizontal slit-shaped aperture leading to a chamber which narrows in the direction of flow of carrier medium therein and discharges into a first conduit for evacuation of the lower layer. The upper layer enters a polygonal or cylindrical second conduit at a level above an adjustable flat or otherwise configurated partition which extends into the funnel-shaped section at the intake end of the second conduit and whose inclination can be changed to vary the size of the aperture leading to the chamber.