Advanced / Specialist Non-Destructive Testing

Internal Rotating Inspection System (IRIS)

IRIS is an ultrasonic method for the nondestructive testing of pipes and tubes. The IRIS probe is inserted into a tube that is flooded with water, and the probe is pulled out slowly as the data is displayed and recorded. The ultrasonic beam allows detection of metal loss from the inside and outside of the tube wall. As shown in the below illustration a beam from an ultrasonic transducer is reflected from a mirror set at 45 degrees so that the reflected ultrasonic beam impinges on the tube I.D. at right angles. Part of this beam is then reflected from the tube I.D., while the remainder is transmitted through the wall thickness and is reflected from the tube O.D. The time difference between the two reflected signals is then used to measure the tube wall thickness. The mirror is mounted on a water driven turbine that rotates at speed of about 2 000 rpm. Measurements are then made around the full tube circumference and as the probe head is pulled through the tube the ultrasonic beam maps out a spiral along the tube length. If the probe pulling speed is sufficiently slow, taking into account the inspection parameters, a 100 % coverage of the tube surface is achieved.