| 摘要 |
PURPOSE:To detect the welded part of a piping without peeling the coating, by radiating the radiant ray to the circumferential part of the coated piping and detecting the transmitted radiant ray. CONSTITUTION:A truck 3 which runs in the lengthwise direction of a piping 1 is placed on a rail plate 2 fixed onto a heat insulator 1' of the coated piping 1. Radiant ray sources 16 and 19 are installed on attaching bodies 13 and 13' attached to the truck 3, and detectors 17 and 20 which detect the radiant ray from these radiant ray sources are provided on the attaching bodies 13 and 13'. After these radiant ray sources and detectors are moved vertically and are set to prescribed positions of the circumferential part of the piping, the truck 3 is run repeatedly to count the quantity of radiation based on detection signals from detectors in each position in the lengthwise direction of the piping 1. If a welded part exists on the piping, the radiant ray is absorbed by the bead of the weld, and the counted value in the weld is smaller than that in parts other than weld, and thus, the position of the weld is detected. |
