Abstract: A bottom suspension arrangement is provided for a screw conveyor assembly ed in the pumping of waste water and the like. The assembly includes a stationary cylindrical jacket having an open bottom end, a screw conveyor mounted within the jacket for rotation about a central axis, and an anti-friction bottom bearing on the screw conveyor extending outwardly of the bottom open end of the jacket. The bottom suspension arrangement is attached to the screw conveyor assembly at its bottom end, and comprises a rigid, substantially L-shaped lever having one leg mounted at its terminal end on the bearing and having its other leg spaced from and extending along the upper side of the jacket. A suspension point is located at the terminal end of this other leg for the attachment of a suspension device, and the one leg overlaps radially with the open bottom end of the jacket.

Abstract: A method and apparatus is disclosed for purifying the waste water in an avated sludge-waste water mixture. In dependence upon the state of purification of the waste water, the mixture is ventilated in automatically controlled manner by a gas comprising molecular oxygen. The automatic control of ventilation is exercised by the use of a monitoring device which measures the visible depth of the waste water and, depending upon the measured value, starts-up or switches-off the ventilation.

Abstract: A screen disposed in an elongated sewage channel is cleaned by the movement f a screen comb along the vertically disposed, spaced apart bars of the screen from the bottom to the top. The screen comb is pivotally attached to the end of a rake arm which is formed of a single elongated element. The opposite end of the rake arm is pivotally attached to one end of a support arm (which support arm is pivotally attached at its opposite end to a fixed supporting structure). At a point along the length of the rake arm it is pivotally attached, by way of a laterally extending pin, to a single endless chain moving along a single guide track. Thus, the rake arm is supported in cantilever fashion from the guide track. A supporting roll around the laterally extending pin at a point supported by the guide track allows the pin (as well as the rake arm) to be moved by the endless chain along the guide track.

Abstract: A device for cleaning of a screen located in a water conduit is provided h a screen rake which has a screen comb at one end thereof, the screen rake being mounted and driven by a chain to be guided in a path such that the screen comb cleans the screen, deposits the screenings in a bin and returns to clean the screen again in a continuous and non-interrupted fashion. The path is formed by a number of connected angle bars which are curved in shape and which are placed between a number of chain wheels around which the chain is wrapped for movement thereover. The screen rake is pivotably connected at the end opposite to the screen comb to the end of a hinged support, the hinged support being pivoted around a stationary bearing and having a counterweight at the other end thereof.