NDT.net - February 1999, Vol.4 No.2

APPLICATIONS OF LASER PROFILOMETRY FOR TUBE INSPECTION

Richard D. Roberts
1-800-233-3345

21414 68th Avenue South / Kent, Washington 98032
(253) 872-9500 / (253) 872-8967 (Fax) / Email: RichardR@qi2.com, Web Site: http://www.qi2.com

Related Article:
|Laser Profilometry as a Inspection Method for Reformer Catalyst Tubes|

General Theory of Optical Triangulation
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Optical Triangulation Diagram       Lateral Detector

Small Rotating Probe Head Which Contains Optics, Laser Diode, and Detector
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Example of How Laser Profilometry Probe Collects Data in Tube      1.0" & 2.0" Articulated Laser Profilometry Probes

Example of Full System Which Utilizes Laser Profilometry in Harsh Field Environments
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Applications of Laser Profilometry in Plant Inspections Detectable Failure Mechanisms

  • SMALL BORE TUBING:
    i.e. Heat Exchangers, Feedwater Heaters, Steam Generators, Lube Oil Coolers, etc.
  • TUBING WITH BENDS:
    i.e. Boilers, U-Bend Exchangers, etc.
  • LARGER DIAMETERS:
    i.e. Reformers Tubing, Serpentine Furnace Tubing, Nozzles, etc.

  • Corrosion
  • Erosion
  • Pitting
  • ID Expansion Due to Creep
  • Open Cracking
  • Denting
  • Swelling

Benefits of Technology

  • Accuracy
  • High Resolution
  • Not Effected by Exterior Attachments (i.e. Fins, etc.)
  • User Friendly Data Interpretation
  • Non Contact Method
  • No Couplants Required (i.e. Water, Gel, etc.)

Mussel Damage in Main Condenser Tubing
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Laser Profilometry Image of Mussel Lodged in Main Condenser Tube      Main Condenser Aboard a Super Oil Tanker

Rifled Boiler Tubing
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Laser Profilometry Image of Sample Rifled Boiler Tube      Rifled Boiler Tube

Pitting in Boiler Tubing
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Laser Profilometry Image of Pit in Boiler Tube      Performing Boiler Inspection Using Laser Profilometry Principle

Corrosion Identified with Laser Profilometry in Finned Exchanger Tube
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Laser Profilometry Image of Corrosion in Finned Exchanger Tube      Corroded Finned Exchanger Tube

Example of Catalyst Dusting Damage
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Laser Profilometry Image of Catalyst Dusting in Reformer Tube      Drawing of Catalyst Dusting Failure Mechanism in Reformer Tube

Example of Finned Furnace Tube
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Laser Profilometry Image of Corrosion in Furnace Tube      Finned Furnace Tube

Example of Split in Economizer Tube
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Profilometry Image of Split in Economizer Tube      Split Economizer Tube

Benefits of TechnologyTechnology Limitations

  • Accuracy
  • High Resolution
  • Not Effected by Exterior Attachments (i.e. Fins, etc.)
  • User Friendly Data Interpretation
  • Non Contact Method
  • No Couplants Required (i.e. Water, Gel, etc.)

  • I.D. Surface Inspection Only
  • Requires Surface To Be Clean

LOTIS 5-Inch Probe
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BASIC DATA SHEET (Listed In mm - In Inches )
Probe SizeCalibration Standard DiametersProbe
Probe
Size
Probe OD
(Max. - Can Vary Depending on Centering Device)
NOM 1 2 3 4 5Identification
15.911.713.511.112.313.514.715.9Straight Only
19.112.714.812.714.315.917.519.5Straight Only
25.419.124.120.321.823.625.427.2171.5
31.820.132.524.627.933.038.143.2Straight Only
50.834.548.435.641.948.354.661.0139.7
63.538.160.245.753.361.068.676.2254
88.9Minimum = 76.7 83.878.783.888.994.099.1Straight Only
127.0Minimum = 111.8124.0113.3116.8124.0129.3134.6Straight Only
PROBE DATA SAMPLING PARAMETERS
Resolution ModePitch
(Axial Spacing)
Sample Points Per
Revolution
Revolutions Per
Minute (RPM)
Draw Rate
(mm Per Second)
Draw Rate
(Seconds Per 3.04 Meters)
Date File
(Per 3.04 Meters Approx.)
Very Low2.5180 (80*)180076.240 Sec.464K (206*)
Low1.3180 (80*)180038.180 Sec.928K (412*)
High0.51360 (160*)9007.6400 Sec.4.3M (1.9*)
Very High0.25360 (160*)9003.8800 Sec.8.6M (3.8*)

Jog ModeN/AN/AN/A152.420 Sec.N/A
* 15.9 and 19.1 mm Probe Parameters
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/DB:Article /AU:Roberts_R_D /IN:Quest /CN:US /CT:VT /CT:optic /CT:laser /CT:chemical /ED:1999-02