Device for aerating a liquid

摘要

A device for aerating a liquid comprises an aerating body mounted on a vertical shaft and provided with vanes. The body is arranged to be brought into contact with the liquid surface in order to disturb said surface and thus to introduce air into the liquid. In order to allow the air introduction effect to be varied, the shaft (4) is displaceable vertically with respect to a supporting base (1) by means of guiding and driving means which comprise a bearing sleeve (5) surrounding part of the shaft (4) and rotatably but not slidably connected thereto. The sleeve (5) is provided with a piston (7) which is slidable in a cylinder (8) connected to the base (1) and which is movable with respect to the cylinder (8) by means of a pressure medium supplied to the ends of the cylinder by ducts (13) so as to displace the piston (7) in the cylinder (8) and hence displace the sleeve (5) and shaft (4) in the vertical direction. The pressure medium is provided by a switchable pressure medium source.