Abstract: A programmed bar screen cleaner removes debris from a screen positioned in a channel to prevent the flow of the debris to a liquid treatment. A rake has tines for engaging the screen to move the debris toward and past an upper end of the screen to remove the debris from the screen. Automatic and controllable raking operations are provided to handle the situation in which there is debris jammed in the screen. The jammed debris resists the movement of the rake along the screen, which is sensed via rake motor overloaded, indicated by motor current in excess of a limit. The existence of a jammed rake causes positive release of the rake from the face of the bars, and further movement of the rake is controlled according to the nature of the problem which caused the jamming.

Abstract: A programmed bar screen cleaner removes debris from a screen positioned in a channel to prevent the flow of the debris to a liquid treatment. A rake has tines for engaging the screen to move the debris toward and past an upper end of the screen to remove the debris from the screen. Automatic and controllable raking operations are provided to handle the situation in which there is debris jammed in the screen. The jammed debris resists the movement of the rake along the screen, which is sensed via rake motor overloaded, indicated by motor current in excess of a limit. The existence of a jammed rake causes positive release of the rake from the face of the bars, and further movement of the rake is controlled according to the nature of the problem which caused the jamming.

Abstract: A header conduit provides an elongated passageway through which waste liquid and sludge ("waste") are guided and enter the conduit along a path that is tangential to at least the inner surface of the conduit which such incoming waste first contacts. When the conduit has an inner surface of circular cross-section, the passageway is elongated enough that the incoming waste enters the conduit along a path tangential to the circular surface. To better assure axial flow of the waste in the conduit to an outlet, the passageway provides both the tangential flow and is at an acute angle to the longitudinal axis of the conduit. The incoming waste is thereby provided with an axial component. In this manner, the passageway assures that the energy and momentum of the incoming waste is helical in direction. The waste previously admitted into the header conduit is urged by the newly entering waste to continue to flow helically in the conduit.