Patent ID: 6799466
Filing Date: 2004-10-05
Classification: G01N

Abstract:
An apparatus for inspecting Kraft recovery boiler tubing for fireside defects, the Kraft recovery boiler tubing including a tubular conduit, a portion with an axial length, a fireside, a cold side, and a membrane connecting the tubular conduit with the Kraft recovery boiler tubing, for undesirable characteristics, comprising:a transducer system, said transducer system including a first piezoelectric transducer that induces guided waves in the tubular conduit from the cold side. a toneburst generator that induces two-dimensional Lamb waves that propagate in packets in a sweeping a range of frequencies from 10 kHz to 2 MHz in said conduit, said first piezoelectric transducer having means for partial circumferential loading of said first piezoelectric transducer external to the fireside of said tubular conduit and on the cold side of said tubular conduit and above the membrane connecting the tubular conduit with the Kraft recovery boiler tubing, a second piezoelectric transducer spaced from said first piezoelectric transducer along the axial length of the portion of the tubular conduit that detects the fireside defects of said conduit by receiving said two-dimensional Lamb waves that contain information about the fireside defects, said second piezoelectric transducer having means for circumferential loading of said second piezoelectric transducer external to the fireside of said tubular conduit and on the cold side of said tubular conduit and above the membrane connecting the tubular conduit with the Kraft recovery boiler tubing.