Abstract: A filter apparatus has an elongated shaft, a plurality of filtering elements mounted on the shaft and spaced from one another in direction of elongation of the latter, and means for cleaning the filtering elements. The cleaning means includes a source of cleaning medium under elevated pressure and a plurality of nozzle elements communicating with this source. The nozzle elements face toward surfaces of filtering material provided on the filter elements and are turnable relative to these surfaces. The cleaning medium is ejected from the nozzle elements at a pressure between substantially 5 and 100 bar toward the surfaces of the filtering material of the filter elements so that the cleaning medium removes a cake deposited during a filtering process from the surfaces of the filtering material and thereupon also cleans the filtering material of the filter elements.

Abstract: Anaerobic fermentation of substrates with microorganisms is carried out by a process and with an apparatus wherein fermentation is conducted in a container having an upper cylindrical section, a lower conical section, and between the upper and lower sections an apertured bottom wall containing a plurality of openings. During fermentation, the substrate and microorganisms are recirculated from an outlet in the upper cylindrical section to an inlet in the lower conical section and upward in the container through the openings in the apertured bottom wall at sufficient fluid velocity to agitate the substrate and microorganisms therein and prevent settling of the microorganisms in the container. The apertured bottom wall serves as the sole means of agitation, and the use of this process and apparatus enables a significant reduction in the usual fermentation period.

Abstract: A filter apparatus has an elongated shaft, a plurality of filtering elements mounted on the shaft and spaced from one another in direction of elongation of the latter, and means for cleaning the filtering elements. The cleaning means includes a source of cleaning medium under elevated pressure and a plurality of nozzle elements communicating with this source. The nozzle elements face toward surfaces of filtering material provided on the filter elements and are turnable relative to these surfaces. The cleaning medium is ejected from the nozzle elements at a pressure between substantially 5 and 100 bar toward the surfaces of the filtering material of the filter elements so that the cleaning medium removes a cake deposited during a filtering process from the surfaces of the filtering material and thereupon also cleans the filtering material of the filter elements.

Abstract: A filter apparatus has an elongated shaft, a plurality of filtering elements mounted on the shaft and spaced from one another in direction of elongation of the latter, and means for cleaning the filtering elements. The cleaning means includes a source of cleaning medium under elevated pressure and a plurality of nozzle elements communicating with this source. The nozzle elements face toward surfaces of filtering material provided on the filter elements and are turnable relative to these surfaces. The cleaning medium is ejected from the nozzle elements at a pressure between substantially 5 and 100 bar toward the surfaces of the filtering material of the filter elements so that the cleaning medium removes a cake deposited during a filtering process from the surfaces of the filtering material and thereupon also cleans the filtering material of the filter elements.

Abstract: A filter has a housing defining a closed chamber around a hollow shaft which is rotatable in the housing and which carries a plurality of filter elements so that fluid can be pumped through the filter elements into the hollow interior of the shaft. The shaft is rotatable with the filter elements relative to the housing for cleaning filter cake off the filter elements between filtering operations. An annular and hollow bellows-type seal surrounds the shaft and has one axial end secured to the housing and an opposite axial end engageable with the shaft for sealing the shaft relative to the housing. This bellows-type seal is made of thin and flexible stainless steel. The inside of the seal may be pressurized by a liquid or gas to force the end of the seal against the shaft and form a tight connection therebetween.

Abstract: A vessel is provided for cultivating microorganisms. Said vessel contains a body of liquid, and a hollow rotary impeller is mounted in the vessel and has in the region of its axis of rotation a liquid inlet formed with a venturi-shaped constriction. A plurality of first gas outlets communicate with the liquid inlet in the region of the constriction so that the suction resulting from the liquid flow will pull the gas through these first outlets. A plurality of second gas outlets are located on the periphery of the impeller remote from the first outlet.