Abstract: Described is a drive motor, in particular for a pump, which has a rotor having a drive shaft, and a stator enclosed by a stator casing which is enclosed by an outer casing. The stator casing and the outer casing form an intermediate space which is hermetically sealingly closed off and which is filled with a cooling fluid. The cooling fluid is positively moved by means of a coolant impeller. For that purpose the coolant impeller is coupled to the drive shaft of the electric drive motor by means of a permanent magnet coupling which is in the form of a synchronous coupling, a hysteresis coupling or an eddy current coupling.

Abstract: The invention concerns a method of treating filamentous and flocculating microorganism-bearing effluent, sludge or organic substrates used in biogas installations, for reducing or avoiding the formation of bulking sludge, floating sludge and/or foam, wherein the effluent, sludge or organic substrates is or are guided in a flow passage and in the flow passage subjected to a shear loading which is sufficient to reduce the relative ratio of the number of filamentous microorganisms in relation to flocculating microorganisms. The invention further concerns an apparatus for carrying out the method.

Abstract: Described is a drive motor, in particular for a pump, which has a rotor having a drive shaft, and a stator enclosed by a stator casing which is enclosed by an outer casing. The stator casing and the outer casing form an intermediate space which is hermetically sealingly closed off and which is filled with a cooling fluid. The cooling fluid is positively moved by means of a coolant impeller. For that purpose the coolant impeller is coupled to the drive shaft of the electric drive motor by means of a permanent magnet coupling which is in the form of a synchronous coupling, a hysteresis coupling or an eddy current coupling.

Abstract: A hydrodynamic machine such as an agitator or a pump has a seal at the fluid medium side in the form of a sliding ring in a coaxial opening in the impeller wheel hub. To prevent particle deposits and blockages in the region of the seal the hub engages into a pot-shaped opening in the housing, forming a conical outwardly enlarging annular gap. Formed on the outside of the hub is a spiral means which when the hub rotates produces a fluid flow outwardly of the annular gap to counteract a deposit of contaminating matter such as particles and fibers from the fluid in the annular gap and thus also at the seal.

Abstract: A fluid flow machine wheel as for an immersion agitator or for a waste water, slurry, sewage or feces pump or for a recirculation pump, comprises a shaft hub having an inner hub portion and an outer hub portion, between which there is disposed a hub damping element comprising an elastic material. Blades project from the outer hub portion. Blade damping elements of elastic material are provided between the outer hub portion and each respective blade. The fluid flow machine wheel may have either only the hub damping element or only the blade damping elements. The damping element or elements at least reduce vibration of or damage to the wheel or its drive motor, transmission, mountings for same and so forth, caused by uncontrolled hydraulic conditions or properties and afflux flows.

Abstract: In general submerged pumps are lowered into a trench by means of the power cable (12) which passes into the pump head (10). In order to avoid an unnecessary loading on the power cable (12) the invention proposes providing a protective hose which surrounds the power cable (12) and which is secured to the pump head (10) and by means of which the submerged pump can be lowered without in that case loading the power cable.