ULTRASONIC FLAW DETECTION FOR PIPE

摘要

PURPOSE:To enable the estimation of the residual life of a heat exchanger tube by calculating the distance to the inner wall thereof from the axis center thereof based on an ultrasonic pulse. CONSTITUTION:A high frequency pulse oscillated from a transmittor section 4 is sent to a probe 1 through a receiving section 6 and a cable 5. The high frequency pulse transmitted to the probe 1 is oscillated as an ultrasonic pulse along the axis of a tube 2 with water in a housing 7 and in the tube 2 as medium and irradiates the inner wall of the tube 2 with a mirror 3. Then, echo waves from the surface of the inner wall of the tube 2 and those from the surface of the outer wall thereof 2 though weak are reflected along the axis of the tube with the mirror 3 to be received with the probe 1 and then, transmitted to the receiving section 6 through the cable 5. The high frequency pulse transmitted directly to the receiving section 6 and the echo waves are developed on a time base with a time base section 9 to be displayed 10 while sent to an operational section 12 through an arithmetic input processing section 11 which calculates the distance to the inner wall of the tube from the axis center thereof by a proportional expression allowed for tube material and water temperature. The data thus obtaines are sampled in terms of a heat exchanger tube to estimate the residual life thereof by extremal value statistics.