Near Field Testing

Near Field Testing (NFT) technology is a rapid and cost-effective solution intended specifically for fin-fan carbon-steel tubing inspection. This technology relies on a simple driver-pickup eddy current probe design providing very simple signal analysis. NFT is specifically suited to the detection of internal corrosion, erosion or pitting in carbon steel tubing. The NFT probes measure lift-off or ‘fill factor’ and convert it to amplitude-based signals. Because eddy-current penetration is limited to the inner surface of the tube, NFT probes are not affected by the fin geometry on the outside of the tube.

How it works

NFT technology uses two coils — a transmitter and a receiver. Typically the receiver coil is close to the transmitter coil, taking advantage of the transmitter’s near-field zone — that is, the zone where the magnetic field from the transmitter coil induces strong eddy currents, axially and radially, in the tube wall.