Which scanning device is mounted in a tire-like container filled with couplant?

• A. Rotating scanner
• B. Wheel transducer
• C. Circular scanner
• D. Axial scanner

Answer: (B)

This question tests how a transducer can be designed to maintain continuous acoustic contact on a curved surface. A wheel transducer is built as a wheel-shaped housing, often described as tire-like, and it is filled with couplant. As the wheel rolls or slides over the test surface, the couplant stays in place, ensuring a steady acoustic path and enabling a circumferential scan around round parts. This configuration is ideal for inspecting cylindrical objects where you want to keep constant contact without reapplying couplant.

The other terms refer to different scanning concepts: a rotating scanner is a broader category that may or may not use a tire-like couplant wheel; a circular scanner implies an array arranged around a circle but not necessarily mounted in a tire-like housing; an axial scanner moves along the axis rather than around a circumference.