FLAW DETECTOR FOR SPIRAL SEAM JOINED STEEL PIPE

摘要

PURPOSE: To automatically detect a flaw on a joint seam of a spiral seam steel pipe. ;CONSTITUTION: A flaw detector comprises a path measuring means A for measuring paths SA, SB on A and B sides from a flaw detection gate and a shoulder echo from a supersonic flaw detector 1 and an averaging means B for additionally averages respective values wherein the paths SA, SB are all taken and measured with a constant interval and obtaining averaged path values SC, SD. It further comprises a comparison means C which compares the path values SC, SD with a dead zone value F, outputs a right going output or a left going output for moving a probe arm 1C toward right or left when SC-SDF and SD-SCF respectively, but does not output it when |SC-SD|≤F, a moving output generating means D for outputting an output to an electromagnetic switch 5A or 5B and a probe arm moving mechanism.;COPYRIGHT: (C)1994,JPO&Japio