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Thermographic Testing
Vibrotech
Reliability
Services
Limited
What is Thermography?
Infra Red Thermography is a technique for producing a visible image of invisible (to our eyes) infra red radiation emitted by objects due to their thermal conditions
Thermography
Objectives of Test
• To detect hot or cold area’s
• To determine absolute temperature
• To view Thermal profiles
• To detect temperature loss
Thermography
Infra Red is part of the Electromagnetic Spectrum
• It travels in straight lines at the speed of light
• The useful part is divided between Short and Long wavelengths
• Use of the correct wavelength is essential
Test Equipment
• Hand held portable camera• Battery Powered• Operating at correct
wavelength• Range…..-20°c to +1500°c
• Sensitivity…..0.1°c at 30°c• Real time display • Image Recording capability
Why Thermography?
• Non Contact
• Rapid Scanning
• Data can be recorded in differing formats
• Images produced are comprehensive & reliable
• Is there a viable alternative?
Principles of Operation
• Object radiates infra red radiation• Temperature difference• Differences are detected and displayed visually• Emissivity values must be observed
Advantages
• Non Contact
• Non Intrusive
• Can work at a distance
• Fast and Reliable
• Portable
• Convincing Results
Limitations
• Non Intrinsically safe
• There must be a temperature difference for certain surveys
• Operator experience is essential
• Filters may be needed for certain applications
• Sensitivity and Resolution reduce with distance and angle of view
Electrical
• Switch Gear
• Fuse boxes
• Cable runs
• Electrical connectors
• Insulation
• Transformers
Junction Box
22.7°C
43.7°C
25
30
35
40
SP01
Fan
18.7°C
37.4°C
20
25
30
35
AR01
Fuse Box
23.3°C
38.1°C
25
30
35
LI01
Electrical Connections
Used for the detection of;
• Corroded connections
• Slack / loose connectors• Connectors at too high an
operating temperature• Hot spots
Transformers
• Electrical connections• Insulators• Thermal profile• Operating
temperature• Liquid Level
Refractory Linings
• Torpedo ladles
• Boilers
• Furnaces
• Exhausts
• Ducting
• Kilns
Rotary Kiln - Access Door
77.8°C
129.3°C
80
90
100
110
120SP01
SP02
SP03
SP04
LI01
Kiln - Refractory Lining
22.5°C
48.7°C
25
30
35
40
45
SP01
SP02
SP03
22.6°C
58.5°C
30
40
50
SP01
SP02
SP03
LI01SP04
Torpedo Ladle
Steel Carrying Ladle
Building Surveys
Used to detect,
• Lack of insulation• Cold air infiltration
Draughts• Moisture traps• Hot / warm air escaping• Structural Integrity
• Heating / Cooling
Building Surveys
Building Surveys
Moisture/Water Ingress
• Leaking Roof• Bridged Cavity• Leaking pipes
Refinery & Petro-Chem
• Vessel Surveys
• Blockages
• Defective lagging or insulation
• Steam traps
• Erosion / Corrosion
Vessel Surveys
Flare Stacks
Process Plant
The above Thermograms show how Thermography can be used as a very fast and effective maintenance tool.– The image on the right has a defective cylinder
Process Plant
Thermography may be used for;
• Corrosion surveys• Ensuring valve operation• Leaks• Blockages
Process Plant
• Hot spots• Cold spots (Cryogenics)
• Damaged or missing insulation
• Tank levels
Miscellaneous
• The detection of process or manufacturing faults
• Can be used as a quality control tool
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