eddy current tube testing

eddy current tube testing simulation with indications of 25, 50 and 75 percent of depth , as well as a through hole indication.

[JW]

I did this for Trane 35 years ago testing primarily condenser tubes in Centrifugal Chillers, small condensers and absorption machines. I used a dual coil sensor and a Tektronix oscilloscope. The signals I saw were far different from this single trace. What I saw was more closer to an outline of north america that would make a sharp dip backwards indicating pits starting at 10% depth. Dips forward were generally due to an expansion of the tube near the tube support plate/s. My largest job I worked alone on was testing the California State Central Plant which had 5 Chillers at 1, 500 tons of AC each. Each chiller had tubes at 22 ft. long made from cupronickel 95/5. A total of 9, 500 tubes. 😮
I had to condemn all 9, 500 tubes in the plant. They used once though water as the cooling source which was from a well system that had fine black sand near the Sacramento River. Over the lifetime of the plant the erosion from the sand left long gouged trails down the lengths of the tubes and every so often a chiller would flood internally. The tubes that were covered by the diverter plate were untouched and were my best test tube to compare with. The signal itself for that level of damage was all over the scope and easy to read. The readout we used then was a paper chart like the old ekg machines. The cost to replace the tubes was said to be $400, 000 dollars. About 6 yrs later they tore down the plant and built the new Central Plant that is there today

[gordon]

You should make more of these videos. You could licence them for training.

[MDIBRAHIM-vnpx]

Anybody have clear videos Eddy current testing with calibration

[AndrewMorgan]

This looks like an absolute probe, with one coiled balanced in air and the other coil balanced for thinning of tube wall in a calibration tube, I used to be in NDT, tube testing inspection, also used the differential type 2 coil probe, also did IRIS and DART, as well as Centest for ferrous tubing.