METHOD AND APPARATUS FOR DETECTING DEFECTIVE PORTION ON OUTER SURFACE NOT EXPOSED OF PIPE

摘要

METHOD AND APPARATUS FOR DETECTING DEFECTIVEPORTION ON OUTER SURFACE NOT EXPOSED OF PIPEABSTRACT OF THE DISCLOSUREA method and apparatus for detecting a de-fective portion on the outer surface not exposed of apipe, which comprises: heating or cooling a pipe, theouter surface of which is not exposed, from the sideof the inner surface thereof so that a difference intemperature is produced between a portion of the innersurface of the pipe corresponding to an accumulationof foreign matters or a thinner portion as a defectiveportion on the outer surface not exposed of the pipeand a portion of the inner surface of the pipecorresponding to a normal portion of the outer surfaceof the pipe; then shooting the inner surface of thepipe by means of a thermal imaging system while thedifference in temperature still remains on the innersurface of the pipe to obtain a thermal image ofthe difference in temperature; and detecting theaccumulation of foreign matters or the thinner portionas the defective portion on the outer surface of thepipe by means of the thus obtained thermal image.