PREVENTIVE FENCE AGAINST PROLIFERATION OF PLANKTON IN LAKE WATER

摘要

PROBLEM TO BE SOLVED: To economically and efficiently purify water in a water reservoir or the like, by connecting a sheet to the lower end of floats to form a fence and forming the lower end of fence so as to be vertically movable. ;SOLUTION: When the clearance between the lower end of a fence 1 supported by a plurality of foamed styrol floats 3 and the lake bottom, becomes narrow owing to the fall of water level, air is led to an air chamber 4 at the upper stage through an air pipe 7. The upper stage air chamber 4 expands and floats up while bending a polyester sheet 2 and the length of the fence 1 under the water level gets shorter. When the length under the water level can not be sufficiently shortened only by bending a part of the sheet 2 because of the floating-up of the upper stage air chamber 4, further, air is led to the second air chamber 4 from the uppermost chamber to make the sheet float and moreover bend the sheet. In this way, since damage of the fence can be avoided, water in a water reservoir or the like can be economically and efficiently purified.;COPYRIGHT: (C)1997,JPO