Zirkular-Arrays zur US-Rohrinnenprüfung

An inspection system for steam generator heat exchanger tubes is developed. The probe of the system is a miniaturised circualr array with 64 strip-like elements arranged around its circumferential surface. Such a probe can be used mainly for the assessment of pitting damage and it also enables longitudinal cracks in the tube wall to be detected. The sound field structire is generated with a 6-element subgroup of the array probe according to the principles of phased array beam steering. With the aid of a multiplexing circuit the beam is scanned around the probe. The design of the array prlbe is discussed and experimental results are presented.