To obtain a flexible membrane weir which can surely maintain the erected state of an inner bag in an outer bag by maintaining differential pressure between the internal pressure of the outer bag and that of the inner bag, and a differential pressure control method therefor.
A line 16A for measuring the internal pressure of the outer bag 14A, and a line 16B for measuring the internal pressure of the inner bag 14B are provided with an outer-bag internal-pressure gauge 18A and an inner-bag internal-pressure gauge 18B, respectively. Additionally, a differential pressure gauge 20 is provided between the lines 16A and 16B. An outer-bag air supply valve 28A, an inner-bag air supply valve 28B, and a blower 24 are controlled at least on the basis of information on the differential pressure which is measured by the differential pressure gauge 20, so that the differential pressure can be kept within a constant range or equal to/greater than a constant value.
Kato Kazunori
Katsuichi Nishimoto
Hiroshi Fukuda