| 摘要 |
PROBLEM TO BE SOLVED: To judge the flaw part of a joined part without cutting off a passage for inspection even if length capable of being inspected by one work is larger and load is applied by providing two joining layers between the mutually superposed parts of water barrier sheets of the joined part of them in parallel to the longitudinal direction of the joined part to form a passage ensured in airtightness. SOLUTION: In a joined part 1, the end part of an upper water barrier sheet 2 and the end part of a lower water barrier sheet 3 are superposed one upon another and two joining layers 5, 6 equal in thickness are arranged and interposed between the superposed parts so as to provide an interval and the space surrounded by the upper and lower water barrier sheets 2, 3 and two joining layers 5, 6 is formed as a passage 4 having airtightness. By detecting the fluctuations of the pressure in the passage after the pressure in the passage is reduced, the flaw of the joined part of the water barrier sheets is inspected. As compared with an inspection method pressurizing the interior of the passage, the peeling possibility of the joined part is eliminated and pressure can be reduced with large pressure difference and the length of the joined part inspected at once can be extended and the efficiency of inspection work can be enhanced. |
