The Helix-XT is an ultrasonic based system for inspecting ferrous and nonferrous tubes from the inside. It is based on the Internal Rotating Inspection System (IRIS), which can be applied on almost any material.
With the Helix-XT, accurate thickness measurements can be taken at any location along the tube, so small changes in thickness are measurable and the exact location of pitting and corrosion can be determined.
The system uses an immersion pulse echo technique in which a stream of water is used to spin a turbine containing the transducer: see below.
The turbine rotates a mirror, set at 45 degrees, to reflect the ultrasonic pulses radially into the tube wall.
Reflections from the inner and outerwalls of the tube follow the same path back to the tranducer. The time interval between the first echo–the inner wall–and the second echo–the outer tube wall–measures the tube’s wall thickness.
One hundred percent of the tube is inspected through a helical path, which is created when the transducer head traverses through the tube.