PURPOSE: To ensure the assured detection over the entire region of the coated part, by giving the detection to the entire circumference of the steel tube end by the detection brush while the coated steel tube is being advanced in the spiral movement state.
CONSTITUTION: The control is given to the distribution of positive and negative pinhole detection brushes 39 and 40 via handle 22, screw axle 23, height control screw rod 25, angle control screw rod 30 and others. The state of distribution is changed for positive and negative notch detection brushes 45 and 46, and thus these brushes can touch the outer circumference surface of the coated steel pipe covering a wide range from minimum diameter pipe 50 to maximum diameter pipe 51. In such way, the presence or absence is detected for the pinhole of the coated steel pipe by positive and negative pinhole detection brushes 39 and 40. And the existence is detected for the notch part of the coated pipe by positive and negative notch detection brushes 45 and 46 each.
MORII TAKASHI
TAKAHASHI AKIRA
