Abstract: A boom is mounted for pivotal movement about the center from which the arcuate shape of a filter screen is struck and a cleaner is pivoted to the free end of the boom. A single reversible drive unit is operatively connected to the cleaner for exerting a force thereto to tilt the cleaner toward a cleaning position. A stop operatively and rigidly connects the cleaner to the boom to transmit force from the cleaner to the boom as a pivotal force only after the cleaner is tilted to the cleaning position to thus rigidly connect the drive unit and cleaner to the boom.

Abstract: A bar screen with a screen cleaner has a vertically movable carriage with a rake pivotally connected thereto by pivot arms. A foldable lever assembly is pivotally connected to the carriage and to the pivot arms and assures a fully extended position and a folded position which correspond to a position of engagement of the rake with the screen and a position of disengagement of the rake with the screen, respectively. A lower stop engages the foldable lever assembly and moves it from a folded position to an intermediate folded position at the end of downward movement of the carriage and before the lever assembly reaches fully extended position so that the rake remains in a position of disengagement with the screen during downward movement of the carriage and is held in this position until the lever assembly is moved to fully extended position in response to upward movement of the carriage.

Abstract: A process and apparatus for the batch-wise filtering of a sludge-like material in which the discharge period of the filter press is used for filling a pressure vessel containing air with a pump being also used during this period. During the filtration period the pump can operate solely for feeding the filter press to thereby increase the filtration capacity and reduce the required filtration period. During the discharge period the pump also operates exclusively for feeding the pressure vessel to further speed up the process. The pump can operate continuously and the different steps of the process can be controlled by only opening and closing control valves.

Abstract: This invention relates to apparatus for continuously discharging liquid from a container, such as a waste water tank having a discharge pipe with an inlet located adjacent the container floor and an outlet located outwardly of the container. The liquid flow is controlled by a control unit which operates as a function of the liquid level in the container. The discharge pipe has a riser section between its inlet and its outlet which extends upwardly to an apex section to define an overflow for the liquid. The riser section is adjustable in height which is controlled by control means that always maintains the overflow at a constant elevation below the liquid level in the container.

Abstract: Apparatus for separating liquid and/or solid particles suspended in a gaseous and/or vaporous media stream centrifugally has a curved channel through which the media stream flows. A turbulence chamber is connected to the concave side of the curved channel and accommodates a partial stream of the media stream and has at least one discharge opening for particles separated from the partial stream and at least one exhaust opening for the particle free fraction of the partial stream. At least one of the walls of the curved channel and the turbulence chamber has a cavity for the passage of a heat transfer medium.

Abstract: A process for treating wastewater with oxygen in which oxygen of a higher concentration than atmospheric oxygen is contacted at least intermittently with the water surface and introduced into the wastewater through agitation of the water surface. At least a part of the total volume of the wastewater is treated by carrying out alternately at least two of the following three modes of operation: (a) surface aeration of the wastewater using atmospheric air; (b) oxygenation while maintaining atmospheric pressure above the wastewater; and (c) oxygenation while maintaining positive pressure above the wastewater with the operating modes alternating with each other in response to variations in the volume and/or character of the wastewater being treated. The wastewater is circulated on a horizontal course and is exposed to the introduction of oxygen or oxygen-enriched air in one or several sections of its course whereas it is exposed to the atmosphere on the remainder of its course.

Abstract: A chamber filter press embodying movable filter plates suspended for movement along horizontal guides by an endless transporting assembly driven by a reversible motor and carrying dogging members which cooperate with cams on the filter plates as the press is opened. A switch connected to a time control device reverses the motor when the filter plate which has just been moved rests against the previously moved filter plate and at the end of a preset time the time control device switches the motor from reverse to forward motion. The motor is stopped by a limit switch which is operated by a dogging member at the end of a preset time after the last filter plate has been moved forward.

Abstract: Apparatus for conveying and dewatering wet coarse screenings debris comprises a drag chain conveyor having a conveying flight. A pressing unit is mounted above the conveying flight and exerts a downward pressure on the debris. A trough having a perforated bottom is mounted beneath the conveying flight in the vicinity of the pressing unit.

Abstract: Water having calcium compounds therein is softened by admixing an alkaline precipitating agent and finely divided crystalline calcium carbonate therewith in a mixing zone prior to the addition of a flocculating agent containing trivalent metal ions whereupon the calcium compounds are then changed inside a reaction zone into calcium carbonate. At least a part of the calcium carbonate newly precipitated from the water in the reaction zone prior to addition of the flocculation agent is immediately withdrawn and recycled to the mixing zone.

Abstract: The upper flight of an endless filter belt is supported by a backing sheet as it passes through a feeding and initial partial dewatering zone. The upper flight of the filter belt then passes through a main dewatering zone while being subjected to pressure in a direction to force liquid therethrough. Drainage slots in the upper surface of the backing sheet extend at an angle to the direction of travel of the upper flight and leave narrow strips between adjacent slots which engage the under surface of the upper flight.