Measuring the radiant efficiency of infrared curing heaters
Natural gas-fired catalytic infrared (IR) heaters are a technology of choice for curing of powder coatings, both from a cost-effectiveness and a product-quality standpoint. For optimal performance, an IR heater must have a high radiant efficiency (radiated power output/gross power input). This article discusses the development of a technique to measure the radiant efficiency of IR heaters. The method uses four radiometers in an enclosure, which sweeps a circular arc about the heater.
The radiant efficiency of a catalytic thermal heater was measured at 57 percent, close to the theoretical maximum. This high efficiency translates into fast curing and a high-quality coating. Natural gas-fired IR heaters are used in processes such as thermoforming of plastics, drying of paint, and curing of powder coatings. Power transmitted per unit area is typically 20 times higher with IR than with convective heat transfer. For powder coatings, this means reduced curing time and increased production capacity, with less use of plant space and a lower fuel bill.