A water flow control device is provided that opens to allow water to leave a basin and pour into another pool of water. The water flow control device closes when the level in the pool of water is such that an influx of water could be returned to the basin. The water flow control device has a buoyancy apparatus that opens and closes the water flow control device based upon the level in the pool of water. The water flow control device also has a conveyance channel apparatus that directs water from the basin through the water flow control device in the event the buoyancy apparatus provides an opening to do so.

A water flow control device is provided that opens to allow water to leave a basin and pour into another pool of water. The water flow control device closes when the level in the pool of water is such that an influx of water could be returned to the basin. The water flow control device has a buoyancy apparatus that opens and closes the water flow control device based upon the level in the pool of water. The water flow control device also has a conveyance channel apparatus that directs water from the basin through the water flow control device in the event the buoyancy apparatus provides an opening to do so.

A movable tsunami buffer dam has a unit configured such that a plurality of separate units, each of which having a shape in which a frame made of a light material is sandwiched by a pair of plates made of a light material, is stacked with said plates disposed in a pile; and a locking member for locking said unit to a ground surface such that said unit can rise up from said ground surface and collapse onto said ground surface. The separate units has a structure in which water from a tsunami can advance into a space formed between said plates by said frame.

A required thickness is ensured due to said unit being configured such that said separate units are stacked, and the manufacturing cost is reduced to a greater extent than in the case of a dam configured from a single separate unit of said required thickness, because the big size lumber for obtaining the units is very expensive. The unit is installed in a state of being collapsed on said ground surface at normal times, and when a tsunami arrives, said unit rising up due to the force of the tsunami and the buoyancy of the seawater, resisting the passage of the tsunami and reducing the power of the tsunami.

In order to structurally simplify a frame that is a component of a door body and to reduce required levels of manufacturing precision and assembly precision, thereby reducing a manufacturing man-hour, provided is a floating flap gate 1 installed on a road surface rs at an entrance portion of a building or an underground space. An upward swinging support portion is composed of a bottom fitting 5, a resin plate 6 configured to support a door body 4 when the door body 4 is raised, a water cut-off film 13 covering the bottom fitting 5 and the resin plate 6, a first pressing plate 14, and a second pressing plate 16. The bottom fitting 5 has a convex circular arc-shaped surface 5a. The resin plate 6 has a concave circular arc-shaped surface 6a to be mated with the convex circular arc-shaped surface 5a of the bottom fitting 5.

In order to structurally simplify a frame that is a component of a door body and to reduce required levels of manufacturing precision and assembly precision, thereby reducing a manufacturing man-hour, provided is a floating flap gate 1 installed on a road surface rs at an entrance portion of a building or an underground space. An upward swinging support portion is composed of a bottom fitting 5, a resin plate 6 configured to support a door body 4 when the door body 4 is raised, a water cut-off film 13 covering the bottom fitting 5 and the resin plate 6, a first pressing plate 14, and a second pressing plate 16. The bottom fitting 5 has a convex circular arc-shaped surface 5a. The resin plate 6 has a concave circular arc-shaped surface 6a to be mated with the convex circular arc-shaped surface 5a of the bottom fitting 5.

In order to achieve a swing motion type retractable floodgate using a cost-effective torsion structure, the present invention is provided with a swing pivot support mechanism, a friction shoe, a door bottom support seat, and an operation step during a tidal flow. The support mechanism allows free rotation about three axes and restricts motion in the three axis directions, and a pulling force acts on the support mechanism. The friction shoe dissipates tidal energy during closing operations in a tidal flow to a level that prevents damage to the door. Reactive forces are endured by reducing impact forces with the flexibility and strength of the door bottom support seat. Suitable tidal energy dissipation is performed by selecting friction force strength in the operation step.

In order to achieve a swing motion type retractable floodgate using a cost-effective torsion structure, the present invention is provided with a swing pivot support mechanism, a friction shoe, a door bottom support seat, and an operation step during a tidal flow. The support mechanism allows free rotation about three axes and restricts motion in the three axis directions, and a pulling force acts on the support mechanism. The friction shoe dissipates tidal energy during closing operations in a tidal flow to a level that prevents damage to the door. Reactive forces are endured by reducing impact forces with the flexibility and strength of the door bottom support seat. Suitable tidal energy dissipation is performed by selecting friction force strength in the operation step.

A water flow control device is provided that opens to allow water to leave a basin and pour into another pool of water. The water flow control device closes when the level in the pool of water is such that an influx of water could be returned to the basin. The water flow control device has a buoyancy apparatus that opens and closes the water flow control device based upon the level in the pool of water. The water flow control device also has a conveyance channel apparatus that directs water from the basin through the water flow control device in the event the buoyancy apparatus provides an opening to do so.

A water flow control device is provided that opens to allow water to leave a basin and pour into another pool of water. The water flow control device closes when the level in the pool of water is such that an influx of water could be returned to the basin. The water flow control device has a buoyancy apparatus that opens and closes the water flow control device based upon the level in the pool of water. The water flow control device also has a conveyance channel apparatus that directs water from the basin through the water flow control device in the event the buoyancy apparatus provides an opening to do so.

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.