Being airtightness feature of production manner of the flexible sheet make hollow tube annular body for airtightness feature and the said feature of the orbicular water storage tank and the orbicular airtightness sheet which is constructed to

摘要

PROBLEM TO BE SOLVED: To provide an airtight mechanism for a circular water storage tank capable of easily and effectively protecting sealing of a water storage space when repairing or mending a roof section of the circular water storage tank, and a manufacturing method for a hollow-tube circular body made of a flexible sheet used for the same mechanism capable of expanding in a circular state by injecting a gas and making the inner wall of a main body firmly stick on the peripheral edge section of the circular airtight sheet and preventing mixture of foreign bodies such as dust or the like.;SOLUTION: The airtight mechanism for a circular water storage tank is provided with the circular airtight sheet built on an upper section of the main body of the circular water storage tank, and a hollow-tube polygonal circular body made of a flexible sheet. In the manufacturing method for a hollow-tube circular body made of a flexible sheet used for the airtight mechanism of the circular water storage tank, notches formed by two approximately sine curves joining both edges are formed on 15-60 places in the longitudinal direction of the flexible strip sheet, and a hollow-tube is formed by joining both edges of the flexible strip sheet after joining the flexible sheets adjacent to the notch.;COPYRIGHT: (C)2008,JPO&INPIT