US Patent 6971741 Liquid storage container

A hollow tubular member 170 is provided in the interior of the container 100 having a liquid-supply port 106 underside thereof as seen in the vertical direction, which tubular member is connected at one end to the liquid-supply port 106 and has a float 180 at the other end. Liquid-supply holes 190 and 191 are provided in the tubular member at positions in the vicinity of the float and in the vicinity of the liquid-supply port, respectively. The tubular member is raised vertically upward by the buoyancy of the float. Since the position of the float descends as the surface level of liquid stored in the container descends, the tubular member deforms therewith so that the liquid-supply holes are always located in specific concentration layers, respectively, to be capable of taking the liquid having specific concentrations into the tubular member.