ULTRASONIC FLAW DETECTING DEVICE FOR REACTION TUBE

PURPOSE:To perform speedy, high-precision flaw detection by providing an adapter with an ultrasonic transmitter and a receiver additionally and dipping the adapter in water. CONSTITUTION:A cylindrical holder 10 of two-split structure covers the outer periphery of a reaction tube RT and the adapter 4 is supported slidably along the outer periphery of the reaction tube RT by a parallel link 24 which is fitted so that a guide groove 21 covers the peripheral weld bead RSB of the reaction tube RT. Then the ultrasonic transmitter 22 and receiver 23 are mounted in fitting holes bored in the outer periphery of the adapter 4. When a motor 13 is rotated by operating the console panel of this device like this, a pinion 15 rotates through a variable speed reducer 14 and a large-diameter gear 16 which engages it rotates on the outer periphery of the reaction tube RT at a low speed. Therefore, the adapter 4 is dipped in the water in a water receptacle 6 through a hard pin 17 and an eye plate 20 and rotates around the weld bead RSB at a low speed. Thus, the transmitter 22 and receiver 23 while dipped in the water completely detects a flaw, so the adverse influence of air contamination is removed and the flaw detection is carried out speedily with high accuracy.