rfet1rfet2

 

 

 

 

 

 

 

 

 

  • Driver coil is excited by AC current and generate  magnetic fields.
  • Magnetic fields travel towards the tube wall then forms Eddy Current sheath.
  • Eddy Current itself produces magnetic field and this magnetic field is traveling along the outside surface(Remote Field). Then it re-enters into the tube wall.
  • If there is any wall thickness changes in the path, the magnetic field will be distorted.
  • This will be detected by receiver coil then measure the phase and amplitude changes.
  • Direct field is eliminated by increasing the distance between the two coils ( 2  tube OD Distance)

Advantage of RFET

  • Suitable for ferromagnetic tubes such as those found in heat exchangers and boilers.
  • Localized corrosion, Pittings
  • Equally sensitive to internal and external flaws.
  • Can inspect tubes up to 75mm OD with 5mm thickness.
  • Relatively insensitive to probe liftoff or wobble.
  • Typical pull speed between 6” and 12” per second.