Backflow weir sewer system main duct - has hinged flap held in incoming or on-going line above water at normal level by floating counterweight

摘要

The backflow weir for the outlet from a drain system etc. into an outfall, flowing at right angles to it, allows unrestricted flow into the outfall at normal water level by a hinged flap (5) which shuts at high water. The flap is so mounted in the drain system that at normal water level it is above the cross-sectional area through which flow takes place. A separated control shaft (11) is connected (12) to the outfall (4) at high water. The shaft contains a counterweight (10) coupled to the hinge spindle (6) of the flap. Water, entering the shaft at high water, causes the counterweight to float upwards so that it no longer counterbalances the weight of the flap, which swings down into the pipe. ADVANTAGE - No need for floor height differences, and no slurry and dirt deposition.