MB Inspection offers a full range of pipe and plate scanners covering diameters from 3 to flat plate. The scanner range includes the original Tank Floor Tester (TFT). All use the magnetic flux leakage method. This enables the scanners to detect corrosion pitting on the top and bottom surfaces of all carbon steel pipe and plate.
The tank floor tester was developed for rapid inspection of bulk storage tank floors.
The magnetic flux method allows detection of corrosion pitting in ferro-magnetic steel plates. Related Handscan and Pipescan™ scanners were developed on the same principle to inspect vessel walls, and pipe, from 3" diameter and above.
When an electromagnetic field is induced in a material, the magnetic flux generated tends to remain within that material. However, if a defect disrupts the magnetic field, some of the magnetic flux is forced outside the bounds of the plate. This creates a flux leakage field in the vicinity of the defect. "Hall Effect"? transducers in the scanner detect the flux leakage field and signal the location of the defect.
Once located, the area can be closely scrutinised, using ultrasonic or other techniques, to accurately measure corrosion damage. Equipment sensitivity depends on the material thickness.
Typically the lower bound sensitivity amounts to 30% wall loss in 6.4 mm thick material; 40% wall loss in 12.5 mm material and 60% wall loss in 19mm thick material.