The strange material make multi- selects the thinning section of the tube heavily and measures the wall thickness of the thinning section the manner

摘要

PURPOSE:To conduct measurement at the installing spot by irradiating the surface of a duplex pipe which is made of different materials with radioactive rays and the thickness of which is to be measured to detect a measuring part, and then irradiating the wall of the measuring part of the pipe with radioactive rays to detect the thickness. CONSTITUTION:Radioactive rays 8 are projected to the face of an inner tube 5 of a duplex pipe 6 from a focus 7 obtained by the near focusing method. A film 9 photographed by X rays passing through the surface of the tube has dark and bright parts in density, reflecting the thickness of the inner tube 5. Since the thickness of the inner tube 5 where the X rays pass is different from the thickness (distance L) from the center of the pipe 6, the density distribution is operated with a suitable correction through mathematic treatments, whereby a part where the tube is worn down is detected. Then, after the worn part is shifted sideways in parallel to the film 9 from the center of the pipe 6, radioactive rays 8 are irradiated to the wall of the tube from the focus 7 according to the far focusing method. Accordingly, an image of the worn part is received on the film 9. The density change of the image during the photography is measured to detect the degree of the wear, thereby presum ing the time while the function of the pipe 6 can be maintained.