Combination Near field Remote field probes, a Breakthrough in Ferromagnetic Tube Testing
Detecting Outside Defects with Near Field™ Eddy Current in Heat Exchanger Tubes
RE: GOOD NEWS FOR THE ect 48
There is good news on the ect 48 Eddy Current System with an RFT/NFT combination probe (Patent Applied For) capability for inspecting ferromagnetic tubes.
We recently used the ect 48 RFT/NFT capability to participate in a study by EPRI, the Electric Power Research Institute. The following excerpts are taken from EPRI’s final report, NDE for Carbon Steel Heat Exchanger Tube Support Plates and Tube Fretting, EPRI, Charlotte, NC: 2005, 1011252:
“Remote field, near field, magnetically biased eddy current, and flux leakage examination are invaluable nondestructive evaluation (NDE) methods that are used extensively to investigate integrity of ferromagnetic tubing found in heat exchangers . . . but these methods pose a formidable challenge to characterize tubing flaws underneath or close to carbon steel support structure locations. This phenomenon has been accepted as a limitation by the industry.”
“This report is primarily focused on volumetric tubing flaws such as 360° outside diameter tube fretting.”
“The Near Field™ examination technique was superior in detecting and sizing all tube fretting wear that was provided in this project.”
That’s Eddy Current Technology technology!
To give you some background on this study, EPRI invited all Manufacturers of electromagnetic testing devices for heat exchanger tubes to participate. Five signed up, including ourselves. Two of the companies that signed up never bothered to submit a final report. Of the three that did, the only methods reported on were Remote Field and Near Field™ Electromagnetic Testing. No one submitted a report with the other techniques, such as Magnetic Flux Leakage and Partial Saturation. The three that submitted final reports all reported on Remote Field testing, which just cannot do as well as Near Field™ testing because Remote Field testing gets too much interference from the support plate.