Inspection of pipes
AssigneeImperial College of Science, Technology and Medicine
InventorsPeter Cawley, David Nathaniel Alleyne, Che Wan Chan
Life of this patent
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Abstract
An apparatus and a method for inspecting elongate members, especially pipes, using Lamb waves. The apparatus and method provide for the propagation of an axi-symmetric Lamb wave of a single mode in one direction along the pipe. A receiver is provided to receive the Lamb wave after its passage along the pipe and convert the received wave for storage, processing and analysis to determine whether or not there are faults present in the pipe. The apparatus includes at least one and usually several excitation rings each having a plurality of Lamb wave exciters deployed in equiangular spacing in a ring clamping structure whereby each exciter can be pressed with equal force against the surface of the pipe under inspection.
Claims18
An apparatus for inspecting a pipe comprising:
- a first excitation ring;
- a second excitation ring, the first and second excitation rings being adapted to be secured to an exterior wall of a pipe;
- a plurality of angularly spaced wave exciters secured to each of the excitation rings, each wave exciter being controlled to induce a propagation, in a single direction along the pipe, of one of:
- (a) a single mode axially symmetric Lamb wave,
- (b) a single torsional mode wave, and
- (c) a single flexural mode wave;
- receiving means for receiving a wave;
- and
- analyzing means for analyzing the received wave and assessing a condition of the pipe.
A pipe inspection apparatus, comprising:
- a first excitation ring;
- a second excitation ring, the first and second excitation rings being adapted to be secured to an exterior wall of a pipe;
- a plurality of angularly spaced wave exciters secured to each of the excitation rings, each wave exciter being controlled to induce a single mode propagation along the pipe of one of:
- (a) a single mode axially symmetric Lamb wave,
- (b) a single torsional mode wave, and
- (c) a single flexural mode wave,
- each of the exciters also receiving one of the propagated waves;
- and
- analyzing means for analyzing the received waves and assessing a condition of the pipe.
A method of inspecting a pipe, comprising the steps of:
- inducing a propagation, in one longitudinal direction of the pipe,
- (a) a single mode axially symmetric Lamb wave,
- (b) a single torsional mode wave, and
- (c) a single flexural mode wave;
- suppressing all but the single mode of the Lamb wave propagating in either longitudinal direction along the pipe;
- suppressing the propagation of any Lamb wave in one longitudinal direction of the pipe;
- receiving the propagated wave;
- and
- analyzing said wave for identifying structures in the pipe, a condition of the pipe being determined as a function of the identified structures.
Dependencies are inferred from the claim text.