The Overflow Valve or Surface Valve is designed for free flow installations where the upstream level must be controlled. The concept includes an articulation axis at canal base and a hydraulic operating element composed of one or two hydraulic cylinders located in the center or on both sides.
The valve deck, with a lenticular profile or with the shape of a “fish belly”, rigid in torsion, regulates the upstream water level. It has a natural tendency to open under the action of water pressure and presents itself as the preferred overflow equipment for barrages.
Its maximum evacuation capacity is obtained by an water level monitoring system and can be upgraded by several energy free hydraulic safety devices.
As an option, a high position locking device, manual or automatic, can be fitted in order to safely maintain the water reserve during maintenance operations.