| 摘要 |
PURPOSE:To detect the presence of a defect accurately and quickly by having an electrolytic liquid filling a metal pipe lined with an insulating material while an electrode is inserted into the metal pipe and a voltage is applied between the electrode and the metal pipe to detect current. CONSTITUTION:A metal pipe 10 lined with an insulating material 12 is closed with a lid 14 at the lower side end thereof and an electrolytic liquid 16 is injected into the pipeline 10 to the fullest from the upper end thereof. Then, an electrode 22 is mounted at the center of the lid 14 piercing it and a voltage is applied between the metal pipe 10 and the electrode 22 from a power source 26. In this case, if the inner surface of the metal pipe 10 is covered evenly with a lining material 12, the electrode 22 and the metal pipe 10 are insulated so completely to keep current from flowing. But when there is any defect in the lining material 12 and the inner surface of the metal pipe 10 is exposed at the defect, current will flow through the electrolytic liquid 16 thereby permitting accurate and quick detection of possible defects. |
