Spillway for discharging extraordinary floods at dams having at least two flood discharge structures
AssigneeGTM Entrepose
InventorFrancois Lemperiere
Life of this patent
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Abstract
For the purpose of providing a more economical alternative to conventional control gates for the quasi-permanent closure of all or part of the length of the overflow spillway of a dam except when discharging extraordinary floods, the invention consists of installing on the sill of the spillway a water level raising means comprising at least one heavy element, held by gravity on the sill, the water level raising means or its element being designed to overturn at a predetermined head corresponding to a headwater level not higher than the predetermined maximum water level in order to discharge extraordinary floods, smaller floods being discharged by a separate flood discharge structure.
Claims17
Spillway for discharging extraordinary floods for dams and similar works having two flood discharge structures, one of the two discharge structures being an overspill sill whose crest is set at a first predetermined level lower than a second predetermined level corresponding to a maximum reservoir level for which the dam is designed, the difference between the said first and second predetermined levels corresponding to a predetermined maximum discharge of an extraordinary flood, and a moveable water level raising means closing off the said sill, wherein the water level raising means comprises at least one heavy rigid element resting on the crest of the overspill sill and held in place thereon by gravity, the said element having a predetermined height at least equal to the difference between the first and second predetermined levels and being of such size and weight that the moment of the forces applied by the headwater on the element comes to equal the moment of the gravity forces tending to maintain the element in place on the overspill sill so that consequently the element is destabilized when the water reaches a third predetermined level at most equal to the second predetermined level.
Dependencies are inferred from the claim text.