Infrared Application of the Month #1:
Drying Water-based Stain on Wood
A manufacturer of wood-based panels wished to replace their solvent-based staining system. They chose a mediumwave IR system from Heraeus Noblelight to dry water-based stain prior to UV lacquering. The new system is faster (the water-based stain is completely dry prior to lacquering), the design is compact, and installation was facilitated within the existing line.
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Infrared Application of the Month #2:
Softening Paint on Steel Sheets Prior to Rollforming
A manufacturer of rollformed steel sheets had used a gas-heated air oven to soften paint on PE-coated sheets, but wanted greater control over the process. The solution was a shortwave conveyorized oven from Heraeus Noblelight. Heaters are activated by photocells that sense the product; IR power is regulated and switchable in zones depending on desired line speed and product thickness.
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Tech Center Spotlight:
Carbon Mediumwave Heaters
High heating efficiency and rapid cool down make the mediumwave carbon heater from Heraeus the only medium-wave heater to offer you shortwave response times. Suitable for all medium-wave applications, this heater also offers the capability to match temperatures to the optimum absorption wavelength for each application. Together, these features eliminate overheating and contamination of sensitive substrates.
A particular large portion of medium wave radiation is absorbed in water, solvents and plastics and converted into heat. This allows significant benefits: carbon heaters dry printing inks, with less stress for the paper because the radiation acts more intensively on the ink. The high power heater increases print drying speed and reduces drying time. It also heats plastics in a targeted manner, with less heating of the surrounding environment.
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Special Designs:
Slot Heater
Infrared heater with a slot in one of the tubes, working like a drying channel for fibers or ropes. Twin tube made of quartz glass, gold coating around the whole heater. Fast response medium wave heater. The special slot design makes drying very intensive and efficient.
A wide assortment of other special design heaters is available from Heraeus. Click HERE for details.
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Technical Learning: Advantages of IR Technology, Part 2
High Speed and High Efficiency
As a result of the greater heating rates and the high degree of control available with electric IR process heating, most products can be heated much more rapidly than in a convection oven. Thus, it is possible to decrease the product's residence time in the heating unit and increase the throughput of products. This enables manufacturers to make better use of their production facilities.
For example, an electric IR oven can provide a high heating rate to cure paints (including hard-to-cure, water-based paints) in a fraction of the time required in a convection oven. High heating rates are possible for curing paint in an IR oven because the short-wave IR radiation may be partially transmitted through certain coatings to heat the substrate.
The times to heat various materials in both An electric IR oven can heat many materials far more quickly than can a convection. For example, for steel and aluminum, the time to heat 0.05 inch thick panels to 300°F (149°C) is more than six times faster in the electric IR oven.
For plastic and wood, the time differences are even more dramatic. The higher heating rate supplied by an IR oven causes the surface temperature to rise to 300°F (149°C) without fully heating the interior of the material. In a convection oven, it takes much longer to reach 300°F (149°C) because of the lower heating rate and because the product is heated throughout.
For curing a coating on plastic or wood, an IR oven has an advantage in that the coating can be heated to the curing temperature without appreciably heating the material in depth. Thus, a coating could be cured without overheating and damaging the material. Furthermore, the cool-down time would be less because the material would not be heated in depth.
Electric IR heating is capable of delivering a higher percentage of the input energy to the product than convection oven heating. Due to the higher efficiencies of the IR system, the per-product processing cost can be comparable to -- or lower than -- gas convection. Furthermore, the long preproduction heat-up times required for convection ovens waste energy that would, in an IR system, be put into heating the product. Electric IR heating is efficient because more heat is delivered to the product, not lost to the surrounding air and not up a flue.
to be continued in the next issue...
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That's it for this month's issue of Application Notes for IR Heating. Feel free to encourage your colleagues to subscribe. Just click HERE to send them an invitation to subscribe. It's quick, easy, FREE, and no-obligation.
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