| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for inspecting airtightness in tank by which the defective spot of a weld line can be discovered and specified accurately and easily. SOLUTION: An exhaust pipe 14 and a pressure regulating valve 15 which are connected to an exhaust blower are respectively attached to manholes 11 and 12 provided on the top of a tank 1. Firstly, an inspector 21 enters the tank 1 while the tank 1 is maintained in an empty state and sprays a soap-and- water solution 23 upon a weld line 22 in the tank 1. Then the air pressure in the tank 1 is reduced to -50 mmAq. The tank 1 has exhaust ports 16 (16a and 16b) connected with vinyl hoses 10, and the evacuated state in the tank 1 is confirmed on a U-shaped manometer 19. In case the weld line 22 has a defective spot 24, the spot 24 can be discovered and specified accurately and easily when the pressure in the tank 1 is reduced, because outside air infiltrates into the tank 1 through the spot 24 and the sprayed soap-and-water solution 23 bubbles.
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