Occasionally, water or waste water is collected and needs to be returned back to the source, a holding tank, reservoir, river or sea. The returned liquid is transported by pipes back to the discharge point. If the end of pipeline is not covered, then foreign matter and even animals can get inside the pipeline when there is no flow coming out of the pipe.

Also, if the water level at the source rises and reaches a level above the discharge pipe, then the liquid can flow back up the pipeline.

To prevent these problems, a flap valve is mounted at the open end of pipe line.

A flap valve is a kind of check valve consisting of a body and disc. It can be used in both sewage and clean water media as long as correct materials are selected. When the outflow begins, the disc is pushed forward by effect of the flow. The disc angle is slightly offset to the vertical (typically 5 Deg) – so when the flow stops , the disc closes by gravity and effects a water tight seal between the disc and body seat.

Flap valves are mounted at the end of a horizontal pipe line. The shaft should be in the horizontal position and the mounting flange should be in the vertical position. The flap valve can either be bolted to the flanged end of the pipeline or directly to the wall surface at the end of the pipeline providing that it is smooth and vertical.

There is no need regular maintenance required for these valves, especially if they are installed in clean water pipe-line. If it is uninstalled, we recommend cleaning inside. For dirty water or sewage discharge, it is recommended to hose down from time to time to remove any trapped debris.