Abstract: A pump unit comprises an electric motor (11) and a centrifugal pump coupled thereto, whose pump impeller (14) is located on an extension of the motor shaft projecting into the pump casing (13) and has annular sealing members (141) on the back facing the motor (11) which, on delivering sewage or similar liquids, prevent the penetration of filamentary or fibrous constituents contained in the flow medium into the space behind the pump impeller (14). The annular sealing members, which are movable relative to one another, have on their periphery axially directed and preferably corrugated or sawtooth or trapezoidal profiling. The axially projecting corrugations or the like can preferably run round the periphery and the profiled edge portion of one ring can be at least substantially covered by the unprofiled edge portion of the other ring.

Abstract: An aerator device which includes a submersible unitized electric motor-pump assembly designed by a housing in which is an electric motor having a shaft projecting therefrom and carrying a pump impeller, a second housing having a liquid chamber in which is located the pump impeller, a first opening in the second housing through which the pump impeller is insertable into the liquid chamber, a second opening in the second housing in general axial alignment with the first opening through which liquid is drawn into the liquid chamber, first and second plurality of nozzles arranged in generally axially aligned pairs for directing a liquid discharge from the liquid chamber in generally radially outwardly directed streams to atmosphere, and an aerator chamber opening into individual aerator chambers between the pairs of nozzles for aerating the liquid prior to the discharge thereof into a body of water within which the device is adapted to be submerged.

Abstract: The disclosure is of a device comprising a submersible electric motor-pump assembly, a substantially annular inner chamber closely surrounding said pump and connected to the delivery thereof, a substantially annular outer chamber surrounding said inner chamber, an air supply conduit connected to said outer chamber, and a plurality of nozzle elements constituting ejector nozzles in the boundaries of said inner chamber and said outer chamber whereby liquid escapes from said inner chamber and entrains air from said outer chamber and is discharged in the form of aerating jets.

Abstract: A sewage pump immersible in a conveyed medium and including an electric motor and a pump member connected therewith with there being also a suction opening. The sewage pump has comminuting devices arranged no further downstream than in the region of the suction opening for comminuting sucked-in admixtures. A principal feature of the sewage pump is that elements selectively of the retaining and repelling type are provided in combination with the comminuting devices for acting on the suction of the pump member to counteract the suction flow.

Abstract: An apparatus for introducing air into a liquid including an aerator housing having inner and outer walls defining an inner pressure chamber and an outer air chamber with jet nozzles being carried by the inner walls and opening radially outwardly for directing liquid jets from the pressure chamber through the air chamber, catching nozzles carried by the outer wall and opening outwardly therefrom in alignment with the jet nozzles for receiving a combined liquid and air flow therefrom, a driven liquid pump in the pressure chamber and a compressed air generator driven by a motor and carried thereby, and an air conduit leading from the compressed air generator into the air chamber.

Abstract: A submersible pump with guide means wherein guide elements include a guide sleeve provided with an aligning gap which during lowering of the pump assembly slides upon an aligning rail connected to the foot of the delivery conduit of the pump.