Mechanical integrity monitoring of heat exchanger Nondestructive methods such as eddy current testing.
2.
Tubing inspection is generally limited to non-ferromagnetic tubing and is known as conventional eddy current testing.
3.
In the traditional version of eddy current testing an alternating ( AC ) magnetic field is used to induce eddy currents inside the material to be investigated.
4.
The applicability of the traditional version of eddy current testing is therefore limited to the analysis of the immediate vicinity of the surface of a material, usually of the order of one millimeter.
5.
In shell and tube heat exchangers, Eddy current testing is sometimes done in the tubes to find locations on tubes where there may be leaks or damage which may eventually develop into a leak.
6.
The applicability of the traditional version of eddy current testing is therefore limited to the analysis of the immediate vicinity of the surface of a material, usually of the order of only a few millimeters.
7.
A recent technique, referred to as Lorentz force eddy current testing ( LET ), exploits the advantages of applying DC magnetic fields and relative motion providing deep and relatively fast testing of electrically conducting materials.
8.
In principle, LET represents a modification of the traditional eddy current testing from which it differs in two aspects, namely ( i ) how eddy currents are induced and ( ii ) how their perturbation is detected.
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