METHOD AND DEVICE FOR LONG-RANGE GUIDED-WAVE INSPECTION OF FIRE SIDE OF WATERWALL TUBES IN BOILERS
First Claim
1. An apparatus for long-range torsional guided-wave inspection of the fire side of a waterwall tube, the apparatus comprising:
- a plate magnetostrictive sensor probe;
a frame for positioning the plate magnetostrictive sensor probe against an external surface of the waterwall tube;
a compressible/expandable bladder positioned between the frame and the plate magnetostrictive sensor probe in a manner that directs the magnetostrictive sensor probe against the external surface of the waterwall tube; and
an electromagnet positioned across the frame in a manner that pulls the frame and the associated bladder and plate magnetostrictive sensor probe against the external surface of the waterwall tube.
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Accused Products
Abstract
Methods and devices for inspecting waterwall tubes for the detection of fire side damage over a long length of the tube are described. The system of the invention uses a magnetostrictive strip and a flat coil-type plate magnetostrictive sensor (MsS) that are held in place on the waterwall using a specially designed frame and an electromagnetic circuit. The magnetostrictive strip and plate type MsS are positioned against a tube in the waterwall using an elastomeric pad or a fluid filled bladder to achieve close contact and good mechanical coupling between the magnetostrictive strip and the tube surface. When current activated, the electromagnet holds the entire assembly in place and provides a DC bias magnetic field required for plate magnetostrictive sensor probe operation. Long-range guided-waves are pulsed into the tube and reflected signals are detected within the same sensor structure. The received signal data representative of a long section of the tube under investigation is then analyzed for the presence of anomalies and defects. When data acquisition for a particular tube or tube section is completed the electromagnet is turned off and the entire device is moved to the next tube in the waterwall.
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Citations
18 Claims
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1. An apparatus for long-range torsional guided-wave inspection of the fire side of a waterwall tube, the apparatus comprising:
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a plate magnetostrictive sensor probe; a frame for positioning the plate magnetostrictive sensor probe against an external surface of the waterwall tube; a compressible/expandable bladder positioned between the frame and the plate magnetostrictive sensor probe in a manner that directs the magnetostrictive sensor probe against the external surface of the waterwall tube; and an electromagnet positioned across the frame in a manner that pulls the frame and the associated bladder and plate magnetostrictive sensor probe against the external surface of the waterwall tube. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A method for long-range torsional guided-wave inspection of the fire side of a waterwall tube, the method comprising the steps of:
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providing and positioning a plate magnetostrictive sensor probe over an external surface of the waterwall tube along a portion of a circumference of the tube; providing and activating an electromagnet across the plate magnetostrictive sensor probe to draw and maintain the sensor probe into contact with the external surface of the waterwall tube; and connecting the magnetostrictive sensor probe to magnetostrictive sensor instrumentation and generating and receiving interrogation signals into and from the waterwall tube under inspection. - View Dependent Claims (14, 15, 16, 17)
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18. A method for long-range torsional guided-wave inspection of the fire side of a waterwall tube, the method comprising the steps of:
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preparing the external surface of the waterwall tube to provide mechanical compliance between the waterwall tube and a sensor probe to be placed in contact therewith; providing and positioning a plate magnetostrictive sensor probe over the prepared external surface of the waterwall tube along a portion of a circumference of the tube; providing a strip of magnetostrictive material between the plate magnetostrictive sensor probe and the prepared external surface of the waterwall tube; providing and positioning a compressible/expandable bladder over the plate magnetostrictive sensor probe; providing and positioning a rigid inverted U-shaped frame over the compressible/ expandable bladder and plate magnetostrictive sensor probe; providing and activating an electromagnet across the plate magnetostrictive sensor probe to draw and maintain the sensor probe into contact with the external surface of the waterwall tube; establishing a bias magnetic field within the magnetostrictive strip to optimize torsional wave magnetostrictive sensor operation using the activated electromagnet; and connecting the magnetostrictive sensor probe to magnetostrictive sensor instrumentation and generating and receiving interrogation signals into and from the waterwall tube under inspection.
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Specification