Foldable drain pipe for a decanter in a water treatment system

Abstract

A foldable drain pipe for draining effluent from a decanter in a settling tank in a water treatment system, comprising a plurality of pipe sections sealingly connected together end to end by pivotable elbow coupling pairs to form an articulated drain foldable in a vertical direction. The drain pipe is attachable at an upper end to the decanter and at a lower end to a tank outlet in the tank wall. The drain pipe can support its own weight and cannot come into contact undesirably with any other portion of the tank wall. The pipe unfolds upward as needed when the decanter and effluent level are high, and folds compactly between the decanter and the tank outlet when the decanter and effluent level are low. Multiple hobble apparatus options may be selected as defined herein to prevent rotational hyperextension of any of the elbow coupling pairs to assure that the pipe folds correctly.