Pulse Eddy Current Control (PEC) for measuring wall thickness without direct probe / control surface contact (LIFT-OFF presence). The PEC control consists in the analysis of the induced currents dispersed inside a conductive component following an electromagnetic variation.
There are 3 stages:
The emission phase (of the pulse) during which the probe introduces magnetic fields that penetrate and stabilize in the thickness of the component.
The cut-off phase, which introduces strong induced currents into the component when the magnetic field emission is abruptly stopped.
The receiving phase (of the impulse), in which magnetic sensors measure the decay of the induced currents spread in the thickness of the material.
Data acquisition method:
Grid mapping - extremely versatile
Dynamic mode (unique to Lyft) - higher resolution - better detection for small defects Measurements on the external surface, with or without sheet metal (aluminum, galvanized steel) or insulator, on splits and blisters.
Can be used near or on elbows, supports, valves, metal structures, nozzles, flanges, pipe supports and through: concrete, polymer coating, wire mesh, reinforcing rods. Applicable on lines starting from 4 "(102 mm) and insulated equipment that can be inspected with the following combinations of wall thickness / insulation thickness:
Thickness from 3.18 mm to 38.10 mm
Insulation from 0.0 mm to 152.4 mm
Limits:
Edge effect (about the overall dimensions of the probe) near metal structures, this does not allow to discriminate the internal and external side of the defect (under study)
Could not detect small pits
Difficult to use on elbows / bends less than 200mm (8 inches) in diameter.
It can be used for:
Corrosion detection under fireproofing (CUF)
Accelerated Corrosion Flow Detection (FAC) Eddyf's Lyft instrument is used in this control
Technical specification ISO 20669: 2017 - "Non-destructive-testing - Pulsed eddy current testing of ferromagnetic metallic components".
