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US 2024/0118240 A1Published application
Lift-off compensated eddy current system
AssigneeEvident Canada, Inc.
InventorsRémi Leclerc, Benoit Lepage
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Abstract
Techniques for compensating the sensitivity variations induced by lift-off variations for an eddy current array probe. The techniques use the eddy current array probe coils in two separate ways to produce a first set of detection channels and a second set of lift-off measurement channels without the need to add coils 5 dedicated to the lift-off measurement operation.
Claims10
A lift-off compensated multi-frequency eddy current system for indicating a flaw in a material under test, the system comprising:
- an eddy current probe having a set of interface coils, the set of interface coils including:
- at least one first interface coil arranged to induce a first eddy current in the material in response to a first input excitation signal frequency;
- at least one second interface coil arranged to induce a second eddy current in the material in response to a second input excitation frequency that is different from the first input excitation frequency;
- and
- at least one third interface coil arranged to sense a response signal, wherein the response signal is a composite response to the first eddy current and the second eddy current;
- and
- a back-end circuit coupled with the at least one third interface coil, the back-end circuit to:
- receive the response signal;
- and
- extract a lift-off signal and a defect signal from the response signal.
7 more elements
A multi-frequency method for indicating a flaw in a material under test, the method comprising:
- using at least one first interface coil, inducing a first eddy current in the material under test in response to a first input excitation signal frequency;
- using at least one second interface coil, inducing a second eddy current in the material under test in response to a second input excitation frequency that is different from the first input excitation frequency;
- using at least one third interface coil, sensing a response signal, wherein the response signal is a composite response to the first eddy current and the second eddy current;
- and
- extracting, using a back-end circuit coupled with the at least one third interface coil, a lift-off signal and a defect signal from the response signal.
2 more elements
Dependencies are inferred from the claim text.