Abstract: A device is described which accurately and reproducibly identifies points on the circumference of a non-vertical pipe for use as reference marks for pipe inspections. The device comprises a light-permeable disk-shaped chamber having a plurality of pockets spaced about its circumference, a light source transmitting a beam of light through the chamber, and a light-activated switch positioned to detect the light beam. The chamber contains a freely moving ball sized to be retained by the pockets. The device is mounted to revolve about the axis of the pipe. As it revolves the ball moves from one pocket of the chamber to another, interrupting the beam of light and triggering the light-activated switch, thereby indicating that the device has passed to a pre-selected circumferential position on the non-vertical pipe.

Abstract: A device is provided for reducing internal reflections from the tire of an ultrasonic search wheel probe or from within the material being examined. The device includes a liner with an anechoic chamber within which is an ultrasonic transducer. The liner is positioned within the wheel and includes an aperture through which the ultrasonic sound from the transducer is directed.