WATER TANK, TANK COVER AND A METHOD FOR STORING WATER

摘要

The invention concerns a water tank comprising a container part (1) and a lid part (2). The lid part (2) is arranged to float on the water surface of the water enclosed in the container part (1) and is provided with a vertical peripheral surface (10) which will form a narrow channel with the wall of the container part (1). According to the invention, the peripheral surface (10) has a height equal to at least 4 % of the effective depth of the tank. The invention also concerns a tank lid (6, 10) with a peripheral surface (10) with corresponding height. The invention further concerns a method for storing water in such a tank. According to the method, ballast (3) is provided on top of the lid (6, 10) in sufficient amount to press water into the narrow channel to a height of at least 4 % of the effective depth of the tank. A non-corrosive liquid (5) is then added in the narrow channel to form a layer of corresponding height.