Infrared Application of the Month #1:
Tube Forming
A plastics application required higher levels of efficiency for its ovens. The tube forming process requires heat to be evenly applied across the surfaces of the product. A tunnel heater using Heraeus Noblelight twin-tube infrared heaters allowed quick switching on and off, and provided a consistent and thorough heat source for the application. The system uses optical pyrometers for closed loop control and precise temperature measurement.
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Infrared Application of the Month #2:
Thermoforming PE plates for Orthopedic Products
A manufacturer of polyethylene products for orthopedic applications sought an effective heat source for thermoforming of product components. After careful review the company chose a modular infrared system from Heraeus Noblelight. The system employs nine infrared modules positioned inside an existing oven. New electrical design and pyrometer power control are key components of this new, more efficient system.
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Tech Center Spotlight:
Shortwave Twintube Heaters
Shortwave IR heaters from Heraeus are suitable for all applications in which the attainment of high temperatures in the shortest possible time is what counts. Their emission maximum is between 0.9 and 1.6 micron. Among their advantages are high radiation density in the most compact space, and low space requirements.
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Special Designs:
Ring Heater
Designed for horizontal use, this shortwave ring heater, internally focused for intense rapid heat-up of rods, stakes etc. is made of quartz glass, has a diameter of 8 mm, a two-sided connection, and is available with or without the Heraeus gold reflector.
A wide assortment of ring heaters are in stock at Heraeus. Click HERE to for details.
Technical Learning: Introduction to IR Technology, Part 4 (conclusion)
Developments in process heating
During World War II infrared heating became more widely recognized. The main applications were in the metal finishing fields, notably in the curing and drying of paints and lacquers on military equipment. Banks of lamp bulbs were used very successfully, and although by today's standards the power intensities were very low, the technique offered much faster drying than the fuel-fired convection ovens of the time. Production bottlenecks were overcome and military supplies to the armed forces were maintained.
After the urgency of war production had passed, the adoption of infrared heating techniques continued, albeit on a much slower basis. As industries reverted to normal peace time operations, prewar methods of production were reinstated in order to resume full output as quickly as possible, and to provide immediate employment for the returning members of the armed forces.
However, in the mid 1950s the motor vehicle industry again began to show interest in the capabilities of infrared for paint curing, and a number of production line infrared tunnels came into use. The familiar lamp bulbs were by now being complemented by a new tubular lamp of higher radiant intensity but smaller in physical size. This allowed a much higher packing density to be achieved, hence a higher power intensity over a given area of radiant emission.
With the interest in infrared heating now renewed, new types of heat sources (heaters) were developed to fill the ever widening needs of industry. There now exists a variety of types, shapes and sizes with an extensive range of intensities and operating temperatures. This flexibility enables the equipment designer to meet a vast range of process heating requirements, such as paint curing, moisture evaporation, printing ink drying and heating of solid materials. Thus the technique is not restricted to a unique heating condition but may be as powerful or as gentle as a particular process requires.
Summary of benefits
The growth in popularity of infrared systems over the past 30 years stems not only from numerous production benefits provided by this form of heating but also from more mechanized production processes and new heat setting materials being deployed in industry. Certain benefits are, of course, common to all infrared systems, but additional specific benefits are often obtained depending on the process under consideration.
In general infrared systems provide the following:
- Rapid heating of the product. In all but a few exceptional cases radiative transfer of heat is much faster than convection. A more constant rate of heating is obtained because the source temperature is normally much higher than that of the product, even at the end of the heating cycle.
- Low energy costs because of short heating times, and the ability to apply the heat only where and when it is required.
- Cleanliness in operation as the heat sources do not cause contamination.
- Elimination of atmospheric pollution due to the absence of combustion products.
- Ease of control combined with safe operation.
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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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