Abstract: An impeller for centrifugal pumps having at least one blade for delivering solids-containing media has, between a leading edge of the blade and a circumferential direction, an angle ?, and between a leading edge of the blade and a meridional direction, an angle ?. Depending on the dominant speed, the associated angles ?, ? are less than 90°, preferably less than 70°, in particular less than 50°.

Abstract: An impeller for centrifugal pumps having at least one blade for delivering solids-containing media has, between a leading edge of the blade and a circumferential direction, an angle a, and between a leading edge of the blade and a meridional direction, an angle ? Depending on the dominant speed, the associated angles ?, ? are less than 90°, preferably less than 70°, in particular less than 50°.

Abstract: A centrifugal pump with a rotor having at least one blade and a method for configuring the profile of a blade is provided. The blade has a profile which is obtained by superposing a symmetric profile with at least one additional profile and a camber line whose blade inlet angle is smaller than 0°.

Abstract: A method and an apparatus for producing biogas from organic matter including a container (1) which is charged with fermentation substrate by a delivery system (13). At least one stirring mechanism (2) is arranged in the container. The feedback value of at least one measurable variable is detected and transmitted to a control unit (4). A reference variable is also provided to the control unit. The control unit calculates the deviation of the feedback value from the reference value, and actuating variables which modify the power input of the stirring mechanism and/or the composition of the container contents and/or the flow behavior of the container contents are adjusted as a function of the deviation.

Abstract: An impeller of a centrifugal pump is provided. The impeller includes at least two blades (4) for conveying media containing solids. An impeller blade leading angle (?1) is smaller than 0°. The blade angle (?) increases in a first section (9) until a value of 0° is reached. In a second section (10), another increase occurs until a maximum value is reached. In a third section (11), the blade angle (?) decreases again.

Abstract: A method and apparatus for producing biogas from organic matter including a container (1) which is charged with fermentation substrate by a delivery system (13), and at least two stirring mechanisms (2) arranged in the container, the stirring mechanisms having propellers (3) which are rotated and generate mostly horizontal currents of the fermentation substrate in the container. The propeller diameters, the propeller geometries, and the positions of the propellers in the container are selected such that a shared mixing zone of the medium is generated in the container. Data for determining the mean speed and/or the viscosity of the medium in the mixing zone are detected and transmitted to a control unit (4) which varies actuating variables which modify the power input of the stirring mechanism into the mixing zone and/or the composition and/or the flow behavior of the container contents.

Abstract: An impeller of a centrifugal pump is provided. The impeller includes at least two blades (4) for conveying media containing solids. An impeller blade leading angle (?1) is smaller than 0°. The blade angle (?) increases in a first section (9) until a value of 0° is reached. In a second section (10), another increase occurs until a maximum value is reached. In a third section (11), the blade angle (?) decreases again.

Abstract: An axially operating stirring element, preferably a propeller manufactured from sheet metal, having propeller blades arranged radially around an axis (A) and in which at least one propeller blade has a sharpened edge on the discharge or trailing edge side.

Abstract: A centrifugal pump with an impeller which has a single helically-formed blade and which is not sensitive to sand abrasion or seizing of the impeller is achieved by providing the impeller (1) with a shielding plate (3) arranged on the suction side which transitions from an axial course given at the suction inlet of the impeller into a radial course, by providing that the blade entry angle (&bgr;1) in the area which is in danger of cavitation in the event of an abrupt onset of flow is at least 5° smaller than the angle of incident flow (&bgr;0), and thereafter the blade angle &bgr; in the axial region of a meridian section through the impeller (1) increases at least to the magnitude of the blade exit angle (&bgr;2), and finally a blade angle (&bgr;) exceeding the blade exit angle (&bgr;2) in the radial area of the meridian section decreases back down to the magnitude of the blade exit angle (&bgr;2).

Abstract: A centrifugal pump having a housing which includes an impeller mounted in the housing. At least one guide vane is mounted between a hub and the housing and in-line with the impeller. The guide vane has a leading guide. A recess is provided in proximity to the leading edge of the guide vane providing a connection between the spaces located on both sides of guide vane to prevent clogging of the impeller by fibrous components flowing in pump medium.