Cable supported rake arm thickener

Abstract

Support of rake arms in a thickener is by sets of separate support cables and separate torque cables extending from outboard-of-the-center positions of rotating trusses extending radially of the sedimentation tank. The sets of support cables are attached in a vertical plane between spaced positions on a common point on the trusses to spaced radial positions along inner hinged rake arms so that the entire weight of the arms is taken up by the support cables. Torque cables extend from a single point on a truss generally midway of the truss but at a radially offset position from the center line of containing the support cable attachments on the truss or multiple trusses. The torquing or pulling action of the torque cables, also produces no thrust load along the rake arms. This eliminates the need of a heavy large center structure adjacent the rake arm hinges to absorb a rake arm thrust load against the hinges. The hinges are supported by relatively thin posts extending from the rotating trusses. Thus there is no large central structural members with scale build-up impeding the flow of settled material to the central sludge withdrawal outlet. Scale clean-up is reduced in magnitude and frequency due to a much reduced amount of structural steel and structure.