TS 2000 Tube Scanner
The TesTex TS-2000 LFET Tube Scanning System uses the Low Frequency Electromagnetic Technique (LFET) to quickly scan tubing in boiler waterwalls, reheaters and superheaters in utility boilers and large industrial boilers.
Inspection are performed from the tube OD (outer diameter), but flaws can be detected on both the OD and ID surfaces.
In addition, both magnetic and non-magnetic metals can be scanned (as can economizer tubing).
The TS-2000 scanners have concave surfaces to match the OD of the tubing. Depending upon the tube’s diameter, either eight (8) or sixteen (16) sensors are used, and they are equally spaced within the concave surface of the unit. The sensors do not touch the surface of the tube.
Usually a 120-degree span of the circumference is scanned as TS-2000 moves along the tube’s length.
The TS-2000’s sensors are very small–a few millimeters in diameter–greater detection capabilities for smaller flaws such as pitting as well as the display of high resolution, real time, 3-D, color graphics of the scan results. Results can be saves for further analysis or permanent archiving.
The TS-2000 System detects flaws, including corrosion cells and hydrogen damage, caustic and phosphate gouging, oxygen pitting, departure from nucleate boiler, ID pitting, corrosion, and erosion.
Cracking is also detectable and its detection can be optimized by modifying the pick-up coil configuration.
Additional features of the TS-2000 are:
- Special Scanners made that only have ½” stand-off therefore being able to scan reheater tubing
- No surface preparation needed for gas or oil burning boilers
- Quality high-pressure water blasting usually sufficient for coal burning boilers
- 2,000 – 3,000 linear feet of tubing can be scanned in a 10-12 hour shift with one inspection team
- Scanning can be conducted from skyclimbers or hard scaffolding
- Low signal-to-noise ratio
- Scanner sizes from half-inch (½″) OD tubing up to maximum tubing OD
Advantages over Competing Technologies
Other methods of boiler tube inspection include:
- Ultrasound (or UT), which scans for thickness, A-Scan, B-Scan, C-Scan, time of flight diffraction, and phased array;
- RT or X-Ray
- ElectroMagnetic Acoustic Transducer or (EMAT)
For ultrasound and ElectroMagnetic Acoustic Transducer methods, boiler tubing needs to be sandblasted, or spot-prepared for individual discreet UT thickness readings. In addition, neither the ultrasound nor ElectroMagnetic Acoustic Transducer method provide rapid scanning coverage; UT merely involves spot checks while EMAT only scans a strip of tubing less that one-quarter-inch (¼″) wide.
RT/X-Ray methods have obvious deficiencies, including getting coverage and limitations to testing while other outage activities are occurring.
Unlike competing products, for both natural gas and oil burning boilers, the TesTex TS-2000 LFET requires no surface preparation, and in coal burning boilers, a quality, high-pressure water blast usually suffices for the TS-2000 to be effective.
The TS-2000’s efficacy is due to the fact that the TesTex LFET is a non-contact method; the scanner surface containing the sensors does not touch the tubing. Because the TS-2000 operates as a very low frequency (usually 10Hz or lower), any non-magnetic deposits do not affect the passage of the electromagnetic field. In fact, iron oxide does not affect the signal path because it is a very “puffy” material compared to the base metal of the tube.