Patent ID: 8915672

Claim:
A movable breakwater including a plurality of sleeved steel pipes aligned parallel to each other on a straight line and inserted vertically, said plurality of sleeved steel pipes penetrating a bottom of a water into a ground under the water with top faces of said sleeved steel pipes opened to the water, and buoyant steel pipes inserted into the respective sleeved steel pipes in a manner capable of being raised and lowered, the movable breakwater comprising: an air chamber provided in each of the buoyant steel pipes at a position so that an upper end of said air chamber is always under water level while each of the buoyant steel pipes is rising from a lowest position to a completely raised position regardless of the vertical position of the buoyant steel pipes, allowing water to come in and go out as well as being capable of storing compressed air; a buoyancy tank provided at a position under the air chamber in each of the buoyant steel pipes and at a position so that an upper end of said buoyancy tank is always under water level regardless of a vertical position of the buoyant steel pipes, and having gas hermetically sealed in said buoyancy tank; an air charging means for supplying compressed air to the air chamber; and an exhaust means positioned above the air chamber in each of the buoyant steel pipes, for exhausting compressed air in the air chamber out of the buoyant steel pipes, wherein the buoyant steel pipes are raised to emerge from water by buoyancy generated by supplying compressed air to the air chamber by the air charging means and buoyancy of gas in the buoyancy tank.