Abstract: A double screen or double-rack grate for use in the extra-fine screening of waste waters includes two rows of rods in laterally staggered arrangements with one row positioned behind the other in the direction of flow of waste water to be screened. Each rod of one row has a hydrodynamic cross section defined by a thickened head portion. Such row of rods is positioned downstream of a first row of rods including rods with substantially rotationally symmetrical cross sections.

Abstract: An interceptor for the continuous removal of solid matter from a mixture of solids and liquids includes a screening drum rotating while in operation in a given direction of rotation. The mixture is fed to the outer surface of the jacket of the drum, whereby the liquid enters the drum and solid matter remains on the outer surface of the drum jacket. A solids discharge device is provided adjacent the outer surface of the drum to remove deposited solid matter. At least the lower half of the screening drum is surrounded by a tank to which a mixture inlet is connected. A liquid outlet is connected to the interior of the screening drum. The level of the mixture in the tank is controlled in such a way that it is above the level of the cleansed liquid inside the screening drum. The mixture introduced into a flow chamber surrounding the drum jacket flows substantially in the same direction as the direction of rotation of the drum.

Abstract: Lifting device with a higher speed in the downward movement area than in the upward movement area, equipped with a driving motor with brake, a gear and a load pick-up system, which runs on an oval or circular or loop-shaped race via a lower and an upper reversion device and which takes up the load in the lower area and delivers it in the upper area. A driving motor is used whose characteristic of torque versus rotation runs relatively flat and whose number of rotations in the downward movement area is in the ratio of at least 1.5:1 compared to the number of rotations in the upward movement area.

Abstract: A security bar rack for installation in the inlets or outlets of water-treatment plants or power stations comprises a number of hollow tubes. A conductive indicator element with uninsulated external surfaces is stretched within each tube and extends over its entire length. Each indicator element is provided with a separate monitoring circuit which actuates a signal element in a way that a detectable alarm signal is emitted if any change takes place in the dielectric condition of the indicator element/tube assembly. In addition a second signal element is provided which is controlled by the monitoring circuit so as to produce a detectable signal to indicate that the device is in a state of readiness to produce an alarm signal.

Abstract: An electric fish-scaring device for water inlet and extraction structures contains several main and counter-electrodes below the surface of the water and which are connected to a voltage supply unit. To monitor operation, at least one simulator electrode is positioned at a predetermined distance in front of the main electrodes.

Abstract: A conveying device for conveying liquid from a supply well features an upright wall having one major surface and extending into the well, conveying means comprising a disk rotatably mounted about a substantially horizontal axis and a plurality of separations connected to the disk about the axis, the wall abutting the separations, a portion of the surface of the wall, the separations and the disk defining cells for conveying the liquid along at least part of the wall surface, and an output channel defined in the wall and intercommunicating with at least one of the cells when in a position near the top of the disk for emptying liquid from the cells as they reach the position;Whereby, when the disk is rotated, it will move the separations into the liquid and the cells will substantially retain their liquid contents until they reach the position.

Abstract: A method and apparatus for cleaning waste water wherein waste water is charged into an apparatus having a plurality of plates adapted for growing a biological mass thereon, and wherein the biological mass is removed by mechanical means in a predetermined period of time independent from the charging of the waste water into the apparatus, and the cleaned waste water is continuously discharged from the apparatus.

Abstract: A conveying device for water or aqueous liquids and in particular for the conveyance of waste water is provided which includes a rotatable conveying wheel having a plurality of cells defined by inner and outer concentric rings and a plurality of radially oriented separation walls. A single disc is secured to one side of the inner and outer concentric rings so that the cells are open at one side. A stationary wall member is provided, at least in the region of upward conveyance of the liquid, and a receiving vessel is positioned in the discharge region of the conveying wheel.