Abstract: The invention relates to a solution for enriching a liquid with oxygen. For this purpose, oxygen from the ambient air is introduced into the liquid by means of an injector and is partially dissolved in it. The liquid which leaves the injector, and which is laden with dissolved and undissolved gas components of the air, is then introduced into at least one degassing unit (2), which is connected downstream to the injector, for the removal of undissolved gas components that form bubbles in the liquid. According to the invention, the injector involves a multiple injector having at least two injector chambers (11, 12, 13, 14).

Abstract: The proposed rotary pump for transporting liquids containing solids is composed of a pump housing (1) and an impeller (2) disposed on a rotating driven shaft. The pump housing (1) encloses a flow space having an intake region (4) and having a pressure region (5) surrounding the periphery of the impeller (2), as well as also a back space (6) of the impeller. According to the invention, the gap (3) relative to the back space (6) of the impeller is completely sealed opposite the flow space relative to the transported liquid with the solids contained therein, wherein, however, there is provided a connection of the back space (6) of the impeller to the pressure region (5), by which its aeration and venting are made possible.

Abstract: The invention relates to a device for impeller sealing in centrifugal pumps for fluid media, by means of which the gap between pump housing (1) and at least one impeller (2) is completely sealed against a transport of material from the pressure side (3) of impeller (2) to the suction side (4) thereof. According to the invention, a sealing ring comprising a rigid pressure ring (7) as well as an annular elastic sealing lip (8) joined with pressure ring (7) is disposed in pump housing (1) between pressure side (3) and suction side (4), whereby, when the centrifugal pump is in operation, sealing lip (8) is applied in sliding manner over the entire periphery of impeller (2) on a sliding surface (6) formed on impeller (2) in the region of impeller intake (5). For this purpose, the sealing ring is positioned in pump housing (1) by means of an adjusting member (9) and its sealing lip (8) inclined against said sliding surface (6) is pre-stressed.