| 摘要 |
PURPOSE:To improve a system for detecting an open hole of a tubular body by a method wherein a guide pipe through which an extrusion blow molded tubular body is guided by being inserted with a gap, and a wind speed-sensor detecting air blown out from the tubular body side midway in an axial direction of the guide pipe are provided. CONSTITUTION:An extrusion blow molded corrugated tube 7 is successively guided in a guide pipe 1, and when the tube 7 passes, whether or not an open hole exists on the tube 7 is detected. When the open hole does not exist on the tube 7, a wind speed-sensor 11 does not detect any ejection of air from the tube 7 side, and the open hole is judged not to exist. Besides, when any open hole exists on the tube 7, air blown in an air blow process is blown out outside the tube 7 from the open air part, and by detecting a flow of wind owing to the blown out air with the wind speed-sensor 11, an open hole-defective part is judged to exist. |
