Rotary gas washers

A rotary gas washer comprising a casing in which is arranged a droplet generator including a ring of radially extending blades or wings mounted for rotation about a vertical axis and means for distributing liquid over the surfaces of the wings or blades so that during rotation liquid is accelerated by the blades and flows to the peripheral edge of the surfaces from where it is shed to form streams of liquid droplets, a gas inlet scroll for directing the inlet gas to flow around the generator with a radially inward component of velocity and having a height adjacent the generator substantially equal to the axial height of the generator, and a gas outlet scroll having an inlet directly above the inlet scroll and connected thereto by a vertical duct having approximately the same diameter as said ring of blades or wings, wherein the radially innermost portion of the peripheral wall of the inlet scroll is spaced from the periphery of the generator by a predetermined minimum distance to provide around the generator an annular reaction space within the scroll for interaction between the shower of droplets and the gas.