PIPE INSPECTION APPARATUS AND PROCESS

摘要

An openable ring assembly (2) is externally centered around and moved parallel to the centerline of a stationary pipe (3a). As a low-frequency EM source signal (9) is applied to the ring assembly, the time and/or frequency shifts of a detected EM signal from the source signal can be correlated to pipe wall thickness without removal of external pipe insulation (4) and metal cladding (4a), if present. The ring assembly may be opened or expandably segmented to allow pipe thickness detection around obstructions or larger diameter pipe. Centering is preferably accomplished by using rollers (12) circumferentially attached to the ring assembly.