ECA DefHi Probes

See Circumferential Cracks—Rotating Probe Performance, Bobbin Speed

The DefHi® probe is Eddyfi® groundbreaking high-definition, multiplexed ECA probe. It’s designed to inspect the non-ferromagnetic tubing in condensers, feedwater heaters, and heat exchangers.


  • One-pass combination bobbin and array probe
  • Sizing of circumferential and axial cracks*
  • Optimum resolution and uniform sensitivity with oval-coil technology
  • Uncompromising durability (highly kink-resistant cable, replaceable centering devices)
  • Wider frequency range (HW to HF)
  • Convenient analysis with strip chart for bobbin and 2D/3D C-scans for array imaging

*Available with advanced options only


It can efficiently detect circumferential cracks at tube support plates and tubesheets—something conventional bobbin probes notoriously fail at. The DefHi can also detect and size typical defects in any orientation such as wear, corrosion, and micropitting, as well as detect Stress Corrosion Cracking (SCC). The probe’s unique ECA multichannel design offers the same performance as a rotating probe, but at bobbin probe speeds, all in a single pass.


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Better Sensitivity

The DefHi probe overcomes many of the down sides of conventional tube inspection techniques. The probe uses oval coils for a higher coil density, which enables detecting defects and estimating their circumferential length and position, something that a standard bobbin probe can’t do. Bobbin probes are limited to the number of channels of the test instrument—usually 4 or 8—which makes their sensitivity too low to be adequate. Multiplexing the oval coils makes it possible to accommodate up to 128 channels giving it a much greater sensitivity.

This high-definition sensitivity is uniform and can detect defects oriented in any direction, which can’t be matched by other so-called array probes (non-multiplexed array probes) or Air-Conditioning (AC) probes.

Thus, compared to standard ECT bobbin probes, the DefHi can discriminate between the various complex geometries inside heat exchanger and condenser tubing to allow accurately detecting, sizing, and characterizing small-volume longitudinal and circumferential cracks.

Better Speed

Compared to rotating probe technology, the DefHi can typically scan tube ends at a rate of 5 seconds per tube thanks to electronic channel multiplexing. It leverages the physical inputs of the Ectane® 2 test instrument to accommodate up to 128 channels. Hence, the DefHi probe is capable of the same kind of high-speed acquisitions as bobbin probes, while still being able to inspect complete lengths of tubes.

Better Visualization

Along with conventional signals, Magnifi® also uses DefHi’s inspection data to produce 2D and 3D C-scans with color palettes to distinguish between defects—something that’s not possible with bobbin probe data. For example, with the DefHi probe, tubesheets yield angular responses in relation to defects, so they clearly appear on C-scans as having circumferential length and depth, which makes them easy to spot and characterize.



Coil technologies
  • Differential and absolute bobbin
  • Transmit-receive array oval pancake coils
  • 1 × row for circumferential defects
  • 2 × rows for circumferential and axial defects
Maximum inspection speed
  • 1 m/s (39.4 in/s)
  • 9 mm (0.375 in)
  • Non-kink nylon
Calibration standard
  • Modified ASME standard
  • 160 pins