| 摘要 |
PROBLEM TO BE SOLVED: To obtain an inspection method, in which the presence of a hardly visible and small protrusion on the lining face of a small-diameter tube, a longer tube or the like can be determined surely by a method, wherein an inspection jig is inserted into a lining metal tube, whose inner wall is coated with synthetic resin and the jig is moved in the axial direction of the tube. SOLUTION: A lid J of an inspection-jig loading and discharging device D is opened, and an inspection jig C of a prescribed diameter is loaded into the discharge device D from a loading port I. Then, after the lid J is tightened, a valve F is opened, compressed air is supplied into the discharge device D, and the inspection jig C is moved inside a tube in the axial direction of the tube using the supplied compressed air. Then, if a coating protrusion does not exist inside the tube, the inspection jig C is passed smoothly up to the terminal of the tube, however, if coating protrusion exists inside the tube, the inspection jig C is stopped at this position. In this case, the stopping position of the jig C is detected by making inspection-jig passage detecting device G move in the axial direction of the tube. In addition, when the lining metal tube is a curved tube, by the use of a spherical body as the inspection jig C, the presence of a coating protrusion can be confirmed easily.
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