| Infrared Technology | Applications |
	Infrared Technology
	INFRARED RADIATION FEATURES Temperature Measurement Principle Radiation Principle DS RATIO Optical Performance SIGHTING EMISSIVITY EMISSIVITY TABLE BLACKBODY OPTICAL LENSES
	What Is Infrared Radiation? Infrared thermometers operate by means of infrared radiation. Infrared occupies a portion of the electromagnetic spectrum between visible light radio waves. The electromagnetic spectrum is a group of different types radiation. These types include gamma rays, x-rays, ultraviolet light, visible infrared radiation, microwaves, and radio waves. Infrared radiation waves longer than visible light waves. Infrared light waves are not visible to the eye. The term infrared, which means "below red," reflects the fact that light is found just below red light on the electromagnetic spectrum   | TOP |
	Features Noncontact temperature sensors measure IR energy emitted by the target, have fast response, and are commonly used to measure moving and intermittent targets, targets in a vacuum, and targets that are inaccessible due to hostile environments, geometry limitations, or safety hazards. The cost is relatively high, although in some cases is comparable to contact devices.   | TOP |
	Contact and Non-Contact Temperature Measurement Contact temperature sensors must equilibrate with the temperature of the target material. For example, the mercury in a thermometer takes on the temperature of the air and expands or contracts accordingly. When a contact sensor is exposed to a different temperature, it may take some time for it to equilibrate. This is known as the response time of the sensor. In some applications, it is not practical or possible to use contact sensors. Because infrared sensors can measure temperature at a distance with very small response times, they are suited for use in these cases.   | TOP |
	Principle of temperature measurement Thermal infrared detectors convert incoming radiation into heat, raising the temperature of the thermal detector. This change in the temperature is then converted into an electrical signal, which can be displayed and amplified.   | TOP |
	Radiation Principle All objects are composed of continually vibrating atoms, with higher energy atoms vibrating more frequently. The vibration of all charged particles, including these atoms, generates electromagnetic waves. The higher the temperature of an object, the faster the vibration, and thus the higher the spectral radiant energy. As a result, all objects are continually emitting radiation at a rate with a wavelength distribution that depends upon the temperature of the object and its spectral emissivity.   | TOP |
	Field of View (FOV) ratio vs. Distance to Diameter (DS) ratio The field of view is the angle of vision at which the instrument operates, and is determined by the optics of the unit. The FOV is the ratio of the distance from the target to the target diameter. The smaller the target, the closer you should be to it. When the target diameter is small, it is important to bring the thermometer closer to the target to insure that only the target is measured, excluding the surroundings.   | TOP |
	Optical Performance The D:S is defined as the ratio of distance with diameter of spot size which contains 90% of the maximum receiving radiation in front of the target. The precise definition of dimension is shown the following chart. | TOP |
	Laser Sighting The Laser spot is used to indicate the spot of measuring region, but not to emit some something to measure, which is usually misunderstanding. The sensor is located beside of the laser module and with the collimated and same light path with the laser light.   | TOP |
	Emissivity Emissivity is the ability of an object to emit or absorb energy. Perfect emitters have an emissivity of 1, emitting 100% of incident energy. An object with an emissivity of 0.8 will absorb 80% and reflect 20% of the incident energy. Emissivity is defined as the ratio of the energy radiated by an object at a given temperature to the energy emitted by a perfect radiator at the same temperature. All values of emissivity fall between 0.0 and 1.0.     Infrared Radiation   Good Emitter Emissivity ~0.9 Refectivity ~0.1 Poor Emitter Emissivity ~0.1 Refectivity ~0.9   | TOP |
	EMISSIVITY TABLE Material Temp (℃/℉) Emissivity Gold (pure highly polished) 227/440 0.02 Aluminum foil 27/81 0.04 Aluminum disc 27/81 0.18 Aluminum household (flat) 23/73 0.01 Aluminum (polished plate 98.3% pure) 227/440 0.04 577/1070 0.06 Aluminum (rough plate) 26/78 0.06 Aluminum (oxidized @ 599℃) 199/390 0.11 599/1110 0.19 Aluminum surfaced roofing 38/100 0.22 Tin (bright tinned iron sheet) 25/77 0.04 Nickel wire 187/368 0.1 Lead (pure 99.9% - unoxidized) 127/260 0.06 Copper 199/390 0.18   599/1110 0.19 Steel 199/390 0.52 599/1110 0.57 Zinc galvanized sheet iron (bright) 28/82 0.23 Brass (highly polished): 247/476 0.03 Brass (hard rolled - polished w/lines) 21/70 0.04 Iron galvanized (bright) - 0.13 Iron plate (completely rusted) 20/68 0.69 Rolled sheet steel 21/71 0.66 Oxidized iron 100/212 0.74 Wrought iron 21/70 0.94 Molten iron 1299-1399/3270-2550 0.29 Copper (polished) 21-117/70-242 0.02 Copper (scraped shiny not mirrored) 22/72 0.07 Copper (plate heavily oxidized) 25/77 0.78 Enamel (white fused on iron) 19/66 0.9 Formica 27/81 0.94 Frozen soil - 0.93 Brick (red - rough) 21/70 0.93 Brick (silica - unglazed rough) 1000/1832 0.8 Carbon (T - carbon 0.9% ash) 127/260 0.81 Concrete - 0.94 Glass (smooth) 22/72 0.94 Granite (polished) 21/70 0.85 Ice 0/32 0.97 Marble (light gray polished) 22/72 0.93 Asbestos board 23/74 0.96 Asbestos paper 38/100 0.93 371/700 0.95 Asphalt (paving) 4/39 0.97 Paper (black tar) - 0.93 Paper (white) - 0.95 Plaster (white) - 0.91 Plywood 19/66 0.96 Water - 0.95 Wood (freshly planned) - 0.9   | top |
	blackbody A totally absorbing body that does not reflect radiation. It is worth to know that, in thermal equilibrium, a blackbody absorbs and radiates at the same rate; the radiation will just equal absorption when thermal equilibrium is maintained. Manufacturers use the blackbody to calibrate the products with some setup target temperatures, and we are capable to design and manufacture the blackbody calibrators with special demands.   | TOP |
	Optical Lenses There are two types of IR optical elements: reflective elements and refractive elements. As the names suggest, the role of reflective elements is to reflect incident radiation and the role of refractive elements is to refract and transmit incident radiation. We have both optical elements for different types of our products.   Ge lenses---ST68x Series The most popular materials used in manufacturing refractive optics of IR systems are: germanium (Ge), silicon (Si). Germanium is a silvery metallic-appearing solid of very high refractive index (n~ 4), that enables designing of high-resolution optical systems using minimal number of germanium lenses. Additionally, due to its very high refractive index, antireflection coatings are essential for any germanium transmitting optical system. Germanium has a low dispersion and is unlikely to need colour correcting except in the highest-resolution systems, which is used in ST68x serie products.   Plastic Fresnel Lenses—ST65x Series Most of infrared thermometers are simply to detect the target temperatures without higher optical performance, like long distance detection. We have design the Fresnel Plastic Lenses and get the better cost for users in most applications.   | TOP |
	Note that ordinary glass does not transmit radiation beyond 2.5 μm in IR region. Fused silica is characterised by very low thermal expansion coefficient that makes optical systems particularly useful in changing environmental conditions. It offers transmission range from about 0.3 μm to 3 μm.
	Applications
	Because of the specialized nature of infrared measurement, infrared instruments are more widely used in some industries than in others. Infrared thermometers are commonly used are in the steel, glass, and plastics industries. They are also widely used for preventive maintenance.
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	Steel Industry
	The steel industry uses infrared thermometers because the product is in motion and temperatures are very high. A common steel industry application is temperature at the continuous caster, where molten steel begins its transformation into slabs. Reheating steel to a uniform temperature is critical to preventing deformation, and infrared thermometers are used to measure the temperature inside reheaters. In hot rolling mills, infrared thermometers are used to check that product temperatures are within rolling limits. In cold mills, infrared thermometers monitor the temperature of steel while it is cooling.
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	Glass Industry
	In the glass industry, the product is also often in motion, and is heated to very high temperatures. Infrared thermometers are used to measure temperatures in the melt furnace. Portable sensors measure the exterior to detect hot spots, and the temperature of the molten glass is measured to determine proper furnace exit temperature. In flat glass production, sensors measure temperatures at each processing stage. Incorrect temperatures or rapid temperature change can result in uneven expansion and contraction. For bottle and container production, molten glass flows into a forehearth, where it is kept at uniform temperature. Infrared sensors are used to monitor the temperature of glass in the forehearth so it is in proper condition when it reaches the exit. In glass fiber production, infrared sensors are used to monitor the temperature of the glass in the forehearth, and also in the curing oven. Another application for infrared sensors in the glass industry is in windshield production.
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	Plastic Industry
	In the plastics industries, infrared thermometers are used to avoid contamination of the product, to measure moving objects, and to measure plastic at high temperatures. In the blown film extrusion process, temperature measurements to adjust heating and cooling help maintain the plastic's tensile integrity and thickness. In the cast film extrusion process, sensors help control temperatures to maintain proper product thickness and finish uniformity. In sheet extrusion, sensors allow the operator to adjust the die heater and roll cooling to maintain product quality.
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	Preventive Maintenance
	Using a portable thermal imaging system, maintenance personnel can look for potential or actual problem areas. Examples include overheated windings in a motor, plugged cooling fins on a transformer, bad connections on a capacitor bank, and heat buildup on the cylinder heads of a compressor. Any problem that manifests itself with increased heat, or a temperature profile that stands out from its surroundings, can be addressed with a portable thermal imaging system. In many cases, problems can be found in time to correct them, before they require shutting down the process.
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	Chemical Industry
	In the petrochemical industry, refineries use thermal imaging systems in regularly scheduled preventive maintenance programs. These programs include process furnace inspections and thermocouple validation. In process furnace inspection, infrared imagers are used to inspect heater tubes for carbon scale buildup. This buildup, which is called coking, results in higher furnace firing rates and increased tube temperatures. These higher temperatures can reduce heater tube life. Because coking prevents the product from absorbing the tube's heat uniformly, areas where coking occurs appear warmer than other parts of the tube surface when using our infrared thermometer.
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