FGG Inspections

throughout the tube. The ultrasonic pulses are emitted along a
path parallel to the tube axis. A rotating 45 degree mirror then
reflects these pulses into the tube wall. Reflections from the ID
and OD of the tube follow the same path back to the transducer.
The time echo between the ID and OD is used to represent the
wall thickness. As the mirror rotates the UT beam is traversed
around the circumference and each pulse is mapped as horizontal
scan line on the screen of the IRIS 9000. Per revolution 192
readings are taken and 2400 revolutions are completed per
minute. The probe is advanced at a optimum speed of 2.54
meters per minute. This speed ensures 100% coverage. The IRIS
system requires a clean water flow of around 40 psi, and the
tubes to be cleaned down to a bare metal state. The IRIS results
are the most definitive yet to be invented for the inspection of air
cooled and liquid cooled tube bundle heat exchangers.