A flap gate includes a door body and a flap ancillary part. When the door body is in its down position, a movable end portion of the door body is located forward of a supported end portion. The door body changes its position between the down position and a maximum up position. The flap ancillary part applies tilt-up moment to the door body only when the door body is located in a position between the down position and a first position. The flap ancillary part also applies tilt-down moment to the door body only when the door body is located in a position between the maximum up position and a second position.

To effectively block a corner portion from an influx of water. A floating flap gate apparatus 1 constructed to enable a forward end of a door body to swing upwards around a base end thereof. The floating flap gate system 1 has floating flap gates 11 and 12 arranged in a first rectilinear region S1 and a second rectilinear region S2 respectively, and a corner flap gate 21 installed at a corner portion C where S1 and S2 intersect. The corner flap gate 21 has a plurality of door bodies 22 divided by straight lines passing through a part of the corner portion C where lines extending in a width-wise direction of a base end side bottom surface of the door bodies 13 of the floating flap gates 11 and 12 intersect. Among the plurality of door bodies 22, a door body adjacent to the door bodies 13 of the floating flap gates 11 and 12 and the door bodies 22 adjacent to the door bodies 13 are connected by hinge structures 32 and 31 that maintain a water-impervious state. The corner flap gate rises or lowers, following a raising or a lowering of the door bodies of the floating flap gates, thereby making it possible to effectively block a corner portion from an influx of water.

To effectively block a corner portion from an influx of water. A floating flap gate apparatus 1 constructed to enable a forward end of a door body to swing upwards around a base end thereof. The floating flap gate system 1 has floating flap gates 11 and 12 arranged in a first rectilinear region S1 and a second rectilinear region S2 respectively, and a corner flap gate 21 installed at a corner portion C where S1 and S2 intersect. The corner flap gate 21 has a plurality of door bodies 22 divided by straight lines passing through a part of the corner portion C where lines extending in a width-wise direction of a base end side bottom surface of the door bodies 13 of the floating flap gates 11 and 12 intersect. Among the plurality of door bodies 22, a door body adjacent to the door bodies 13 of the floating flap gates 11 and 12 and the door bodies 22 adjacent to the door bodies 13 are connected by hinge structures 32 and 31 that maintain a water-impervious state. The corner flap gate rises or lowers, following a raising or a lowering of the door bodies of the floating flap gates, thereby making it possible to effectively block a corner portion from an influx of water.

A gate, leaf, and method for controlling water levels in a body of water. The gate comprises a moveable barrier (which may be a leaf), a restoring device such as a spring, and a profile. The barrier automatically opens or closes an amount to allow less or more water through as a result of changes in the water pressure in the upstream body of water. This helps maintain a water level in the upstream body of water. The profile disturbs the flow of water through the gate to influence the water pressure on the barrier. The profile may help provide a more linear curve for the water moment on the barrier across the range of barrier positions. A more linear curve for the water moment may help maintain equilibrium with the restoring moment across the range of barrier positions. The method comprises disturbing the flow of water over a barrier to redistribute the pressures of the water on the barrier.

A gate, leaf, and method for controlling water levels in a body of water. The gate comprises a moveable barrier (which may be a leaf), a restoring device such as a spring, and a profile. The barrier automatically opens or closes an amount to allow less or more water through as a result of changes in the water pressure in the upstream body of water. This helps maintain a water level in the upstream body of water. The profile disturbs the flow of water through the gate to influence the water pressure on the barrier. The profile may help provide a more linear curve for the water moment on the barrier across the range of barrier positions. A more linear curve for the water moment may help maintain equilibrium with the restoring moment across the range of barrier positions. The method comprises disturbing the flow of water over a barrier to redistribute the pressures of the water on the barrier.

A mechanical closure device comprises an enclosure having four sides, a top and bottom and defining a discharge opening at the bottom. A floodgate assembly is interiorly removably mounted to the enclosure and comprises a pair of doors pivoted on a hinge assembly between an opened position and closed position. In the closed position, the doors seal against the flange to prevent passage of water through the discharge opening. A discharge drain assembly is preferably disposed on one door and has an opened and a closed position. An appendage is provided to facilitate opening and of the door. Upon removal, the floodgate assembly is stably positionable on a multipositionable service rack. A multipurpose tool is employed unlatching the floodgate doors and slidably removing the floodgate assembly.

A mechanical closure device comprises an enclosure having four sides, a top and bottom and defining a discharge opening at the bottom. A floodgate assembly is interiorly removably mounted to the enclosure and comprises a pair of doors pivoted on a hinge assembly between an opened position and closed position. In the closed position, the doors seal against the flange to prevent passage of water through the discharge opening. A discharge drain assembly is preferably disposed on one door and has an opened and a closed position. An appendage is provided to facilitate opening and of the door. Upon removal, the floodgate assembly is stably positionable on a multipositionable service rack. A multipurpose tool is employed unlatching the floodgate doors and slidably removing the floodgate assembly.

A water control gate pivotable about a horizontal axis. Control may be by a combination of inflatable actuators and ballast chambers in combination with means for preventing over-rotation. Sealing between gate panels and between gate panels and abutments may be by means of seals inflated hydrostatically. The present invention is bottom hinged water control gate actuated by a combination of ballast chambers and inflatable actuators. The invention further includes an inflatable sealing means. The invention is particularly suited for use as a navigation lock gate system or as a flood control gate in a watercourse such as a navigation canal.

A water control gate pivotable about a horizontal axis. Control may be by a combination of inflatable actuators and ballast chambers in combination with means for preventing over-rotation. Sealing between gate panels and between gate panels and abutments may be by means of seals inflated hydrostatically. The present invention is bottom hinged water control gate actuated by a combination of ballast chambers and inflatable actuators. The invention further includes an inflatable sealing means. The invention is particularly suited for use as a navigation lock gate system or as a flood control gate in a watercourse such as a navigation canal.

Single-door flap gates and double-door flap gates are disclosed. A first flap gate includes a first door coupled with a first hinge, a second door coupled with a second hinge, wherein the first door and the second door together form a continuous concave surface, wherein the first hinge and the second hinge couple with a wall, and wherein, when in a closed position, the first door and the second door rest against the wall to cover an opening thereof. The opening may correspond to an end of a pipe that extends away from the first door and the second door. Further, the continuous concave surface may include a radius of curvature configured to be substantially similar to a radius of curvature of the wall, wherein the wall may be interior wall of a cylindrical structure.