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The
TesTex TS-2000 LFET Tube Scanning system is based on the principles
of Low Frequency Electromagnetic Technique (LFET). It is designed to
quickly scan Boiler Waterwall, Reheater, & Superheater Tubing
found in Utility Boilers as well as larger Industrial Boilers.
Inspections using LFET are conducted from the Tube O.D. (outer
diameter). In many cases, Economizer tubing can also be scanned.
PLEASE NOTE: The TS-2000 can scan magnetic and non-magnetic metals.
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The
TS-2000 System uses scanners that have (8) or (16) pick-up sensors
equally spaced within the concave surface of the actual scanner. The
scanners have a concave surface to match the given O.D. of the tube
to be scanned. Generally, a 120-degree span of the given tube is
being scanned as the scanner moves along the length of tubing. This
allows for a real time, 3-D, color graphic
display of the section of tube being scanned. Because these discreet
pick-up sensors are very small (usually a few millimeters in
diameter), they have higher resolution and greater detection
capabilities for smaller flaws such as pitting.
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The
TS-2000 System detects flaws such as Corrosion Cells & Hydrogen
Damage, Caustic and Phosphate Gouging, Oxygen Pitting, Departure from
Nucleate Boiler, ID Pitting, Corrosion, and Erosion. Flaws can be on
the tube I.D. or O.D. Cracking is also detectable and the detection
of cracking can be optimized through modified pick-up coil
configurations.
Waveform from TS2000 showing erosion anomalies in
a waterwall
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Other
methods for the inspection of tubing components in Boilers are UT
(Thickness as well as A-Scan, B-Scan, C-Scan, Time of Flight
Diffraction, and Phased Array), RT or X-Ray, and EMAT
(ElectroMagnetic Acoustic Transducer). For UT and EMAT, Boiler tubing
needs to be sandblasted, or spot prepared for individual discreet UT
thickness readings. Also, neither UT or EMAT
provide rapid coverage of the tube to be scanned; UT merely does spot
checks while EMAT only scans a strip of tubing less that ¼”
wide. RT/X-Ray has obvious deficiencies such as getting coverage as
well as restraints to conducting testing while other outage
activities are taking place.
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For
Natural Gas or Oil burning boilers, the TesTex TS-2000 does not
require any surface preparation. In Coal burning boilers, a quality
high-pressure water blast usually suffices for the TS-2000 to be
effective. This is primarily because the TesTex LFET is a non-contact
method; the actual scanner surface containing the sensors does not
actually make contact with the tubing. Because the TS-2000 operates
as a very low frequency (usually 10Hz or less), any non-magnetic
deposits do not affect the passage of the electromagnetic field; even
Iron Oxide does not affect the signal path, as Iron Oxide is a very “puffy”
material compared to the base metal being tested.
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- Real time, 3-D, color graphic display; data can be saved for further data analysis or permanent record archiving
- Rapidly gets 120 degree coverage on tubes being tested in a single pass of the scanner
- 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
- Straight sections and bends inspected
- 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 ½” OD tubing up to maximum tubing OD
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