Abstract: Device for aerating and/or mixing water in a basin, using a means to impart a rotational motion to the water and having guide means (57) which convert the rotational motion into a combined horizontal and vertical motion of the water. Said guide means can be screw-shaped or plate-shaped elements of suitable shape and dimensions.

Abstract: Apparatus designed to mix and/or aerate waste water by floating on the surface of the water, comprising a motor (2) having a shaft (3) oriented downwards and driving a propeller (4), a guide tube (5), a water-deflecting device (6) and at least two floats, an upper float (9) and a lower float (10), mounted apart one above the other and arranged concentrically relative to the axis of the motor (2), which allow the apparatus (1) to be positioned between two limiting levels relative to the surface of the water:a lower level where only the upper float (9) is situated on the surface of the water and in which the apparatus is suitable for use as a mixer anda upper level where only the lower float (10) is operational and in which the apparatus is suitable for use as an aerator.

Abstract: Apparatus for mixing air with liquid, an aerator or oxygenator, comprises a motor or other power drive generally mounted in vertical position on a floating or a fixed structure, the motor having a shaft extending downwards through an opening in the center area of the float or fixed structure and bearing on its lower part a screw pump portion located in a cylindrical volute section just below the water level. When the apparatus is operating, the waste-water is sucked by means of the screw pump from the bottom of the body of liquid at which the apparatus is positioned and is pushed upwards in order to be diffused by means of a centrifugal impeller having outwardly curved blades, at least one of which extends downward to merge with a spiral shaped portion of a blade on the screw pump.

Abstract: Apparatus for mixing air with liquid (aerator or oxygenator) comprises a motor or other power drive generally mounted in vertical position on a float or a fixed structure, the motor having a shaft extending downwards through an opening in the center area of the float or fixed structure and bearing on its lower part a propeller located in a cylindrical volute section just underneath the waterlevel. When the apparatus is operating, the waste-water is sucked by means of the propeller from the bottom of the body of liquid on which the apparatus is floating and pushed upwards in order to be diffused by means of a rotating diffusion head in the shape of a paddle-wheel. This feature increases efficiency of the installation, allowing the velocity of the fluid leaving the propeller to be kept as low as possible and the dimensions of intake volute and propeller to be increased.