Abstract: The invention relates to an agitating device, in which a hyperboloid agitating body (6) is connected to a drive mechanism (2, 3) by means of a shaft (4). Several ribs (7) running from the circumferential boundary (Ur) in the direction of the shaft (4) are provided on the upper side (0) of the agitating body (6). According to the invention, the efficiency of the agitating device may be improved, whereby a height (h1) of the ribs (7) at least incrementally increases from the circumferential boundary (Ur) of the agitating body (6) in the direction of the shaft (4).

Abstract: The invention relates to a device for gassing liquids, particularly waste water, comprising a gas supply line (1) and at least one gassing element (2), which has a longitudinal axis (L) and can be attached to the gas supply line in a positive manner. In order to simplify the mounting of the gassing element (2), the invention provides that the gassing element (2) has at least one fixing plate (8), which laterally projects relative to the longitudinal axis (L) and which serves to establish a non-positive connection with the gas supply line (1).

Abstract: A stirring and aerating device for activated sludges, wherein a towerlike frame is formed by a carrier element (2, 3) receiving a drive device (1) and at least three support elements (4) extending from said carrier element, wherein an air inlet is provided for an aerating device (7) located in a plane beneath a stirring element (9) that is connected to the drive device (1) by the shaft (10). In order to increase service life of the device, the air is let in through a passage resembling a line that extends in a longitudinal direction in at least one of the support elements (4).