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Basics of Thermal Imaging technology.ppt

The document provides an overview of thermal imaging technology, covering its principles, applications, and training requirements. It explains how thermal imagers detect heat patterns to identify issues in various settings, particularly in maintenance and diagnostics. Additionally, it discusses the importance of understanding emissivity and proper usage of imaging techniques to capture quality thermal images.

Engineering◦
Thermal Imagers 1 WELCOME
Thermal Imagers 2 -9.4°C 74.4°C 0 20 40 60 WORKSHOP ON THERMAL IMAGING
Thermal Imagers 3 AGENDA •Basics of Thermal Imaging •Applications of Thermal Imaging •Choosing a Thermal Imager •Hands on Training
Thermal Imagers 4 What is Thermography? • The use of electronic “cameras” to detect radiant energy or heat • Produces a visual image called a thermogram (or heat picture) • Some cameras infer temperature based on the amount of radiation detected • Thermography is a powerful tool for machine and building maintenance
Thermal Imagers 5 What is Thermography? • Is Not Infrared Photography • The Thermal Imager Produces a Thermal Image • The Thermographer Analyses the Image and draws inferences • Training is an Important part iof Thermal Imaging
Thermal Imagers 6 What is thermography In nature some of the animals have the vision of objects in thermal form and not as normally as we see ! ! ! e.g. a Rattle snake does not see the world as we normally see it but it sees the object / its prey thermally.
Thermal Imagers 7 History of thermography This technology was for years being used for military application to view objects and infiltrations at the borders and so on. Further as the technology flourished this found applications in Medical applications to find out problematic areas in animal & Human bodies.
Thermal Imagers 8 • Is the science of seeing heat patterns using special electronic cameras Rather than seeing light, these remarkable instruments create pictures of heat. They measure infrared (IR) energy and convert the data to images corresponding to the temperature. Thermal imaging Cameras
Thermal Imagers 9 Heat and energy • As an object warms up, it radiates more energy, as photons, based on: – Temperature – Emissivity •Infrared radiation is electromagnetic radiation, similar to light and radio waves •Wavelengths between 2-15 microns are called thermal infrared radiation
Thermal Imagers 10 Heat and Visible light •When an object reaches approximately 644C(1200F) visible light is emitted •Visible light has shorter wavelengths that infrared radiation
Thermal Imagers 11 X-rays Ultra- violet Near Infrared Short Wave Infrared Middle Infrared Long Wave Infrared Microwave Wavelength in Microns (µm) 10-4 10-2 0.28 0.40 0.70 2.00 6.00 8.00 104 15.00 Thermal The TIs are digital imagers that takes long wave infrared thermal pictures in the 7.5 to 14 micron range. The electromagnetic (EM) spectrum is just a name that scientists give a bunch of types of radiation when they want to talk about them as a group. Infrared radiation, like light and radio waves, is a form of electromagnetic energy. The electromagnetic spectrum
Thermal Imagers 12 An Infrared System Windows and Optics Object Environment Detector Electronic Display or Other Output 453¡C SP1 470¡C EMS ¯.85 IR Sensor Collected IR Energy IR Electronics S T
Thermal Imagers 13 How do we get the picture? 120 Elements 160 Elements Each of the element or pixels, contain an accurate temperature value. The Imager, through the use of a complex set of algorithms, assign specific colors that correspond exactly with the temperature value found at the specific X Y coordinate.
Thermal Imagers 14 Thermography Interpretation Higher Temp. Lower Temp. InfraredInstitute.com InfraredInstitute.com InfraredInstitute.com InfraredInstitute.com 21.8°C 34.7°C 22 24 26 28 30 32 34
Thermal Imagers 15 IR Camera •Lens •Detector •Processing electronics •Controls •Image display •Image storage
Thermal Imagers 16 Principles of Heat transfer • Heat is transferred from warmer areas to cooler areas by: – Conduction (in solids) – Convection (in fluids) – Radiation (mainly from surfaces) • Heat flow can be either: – Transient – Steady-state
Thermal Imagers 17 Surface temperature • Our interest is most often to understand internal heat sources: – Abnormal resistance in electrical connections – Mechanical friction – Missing or damaged insulation • What is the relationship between the surface temperatures we see and the internal heat source?
Thermal Imagers 18 Thermal gradient • A thermal gradient exists from the inside to the outside • The primary factors influencing this are: – Conduction – Thermal capacitance – Convection – Load on the system – Emissivity of the surface – State change on the surface
Thermal Imagers 19 •Is non-contact •Applies to most types of equipment and conditions •is obtained without disturbing production •quickly identifies specific locations •allows for detection of problems before failure •can scan large areas quickly to identify areas of concern Thermal imaging Benefits
Thermal Imagers 20 Emissivity and Blackbodies Ideal Blackbody “Real Body” Perfect absorber and emitter Some energy is reflected and transmitted Emissivity () =1 Emissivity () < 1 I I I I R T     I 
Thermal Imagers 21 Radiometric imaging • The camera detects infrared radiation • The source can be: – Reflected – Transmitted – Emitted • Only the emitted radiation tells us about surface temperature.
Thermal Imagers 22 Emissivity • Emissivity is a material property that describes the efficiency with which an object radiates or emits heat. • Emissivity is a value from 0-1.0 – Shiny metals have low emissivity – Non-metals have high emissivity
Thermal Imagers 23 How to set emissivity •Use emissivity tables as guidelines only Measurements below .6 are unreliable — even when you set emissivity correction values •Press F1 or F3 to raise or lower the emissivity setting.
Thermal Imagers 24 Reflected Temperature Compensation •Targets that have low emissivities will reflect energy from nearby objects. This additional reflected energy is added to target’s own emitted energy and may result in inaccurate readings. Use the RTC function to compensate for reflected temperature from emitted energy In some situations objects near the target (machines, furnaces, or other heat sources) have a temperature much higher than that of the target. And in other cases the reflected temperature may be lower than the target such as when a clear sky is reflected.
Thermal Imagers 25 Thermal Imaging is a surface Technology
Thermal Imagers 26 Qualities of a good image • Focus • Brightness • Contrast • Perspective • Composition • Angle of view A good image should exhibit all of these attributes
Thermal Imagers 27 Qualities of a good IR image • Focus • Thermal level • Thermal span • Thermal range • Perspective • Composition • Palette
Thermal Imagers 28 Focus •A well focused image provides clarity and depth not witnessed from an out of focus image. •Focus is the most important step when capturing a quality thermal image and cannot be changed after saving the image.
Thermal Imagers 29 Level and Span • Cameras can be set for “auto” or “manual” rescaling • Auto rescaling adjusts image to highest and lowest temp in FOV • Taking advantage of the manual level and scale adjustment can give you better thermal resolution within the FOV
Thermal Imagers 30 Level and Span Manually adjusted Auto Scaled
Thermal Imagers 31 Resolving detail Resolution defines the ability of the TI to resolve and measure detail at a given distance It is possible to detect objects that are too far away or too small to accurately measure. Just because you can see it doesn’t mean you can accurately measure its temperature
Thermal Imagers 32 Thermal imaging enables service/installer/maintenance technicians to STOP fighting fires and fix problems before they result in large-scale losses. – Find hot spot – Fix equipment before failure – Keep equipment operating efficiently Proactive vs. Reactive
Thermal Imagers 33 CONDITION MONITORING Condition Based Maintenance is the maintenance initiated as a result of knowledge of the condition of an item from performing inspections with condition monitoring technologies.
Thermal Imagers 34 CONDITION MONITORING TECHNIQUES Rotating Equipments Electrical Stationary Equipments Equipment to be Inspected Chillers Transformers Insulation Motors Circuit Breakers Tanks Pumps Capacitors Refractory Fans High-Voltage Switches Roofs Generators Motors Steam traps Compressors Controls Building envelope Gear Boxes Panels Furnace interiors Cables Piping leaks Generators Heat exchangers HV Terminations Valves Inspection Technology Thermography Thermography Thermography Vibration Measurement Oil Analysis Ultrasound Alignment/balancing Ultrasound Combustion analysis Oil testing (ferrography) Corona Testing Air flow Ultrasound Volt/amp Levels Ultrasound Motor circuit evaluation Power factor test
Thermal Imagers 35 Advantages of a Thermography CM Program • Find the problem before it finds you! • Improved less expensive maintenance • Consistent and improved availability • Increase in production rate • Reduced maintenance costs • Extend asset life (less need for capitol expenditure) • Reduce asset base i.e. spare parts • Increased product quality and consistency.
Thermal Imagers 36 Questions?