There are many process applications where infrared will perform better than convection heating. The benefits of infrared are covered in detail in this article.
Tip 1: Cost Savings
Infrared systems will likely be smaller in overall size than convection, resulting in lower overall material and fabrication costs. The smaller footprint can possibly save a substantial amount of floor space.
Tip 2: Rapid Response
The ability of electric infrared heaters to heat up and cool down rapidly is paramount to any discussion about infrared vs. convection oven systems. Electric infrared can be turned on and off quickly like a light bulb. Infrared heaters take only seconds to reach full power. The electromagnetic waves become thermal energy that radiates to the product very quickly. The ability of electric infrared to heat a product is limited only by the product’s ability to absorb infrared energy.
Conversely, gas convection systems need time to heat up and to cool down. To heat a given substrate to temperature using convection, the oven must reach its operational temperature, and the substrate must be subjected to that heated environment for the time needed for it to reach its optimal temperature. The convection oven may take many minutes to reach its operational temperature.
Tip 3: Control and Configuration Flexibility
Electric infrared heating offers the user a high degree of control flexibility. As noted previously, electric infrared heaters can be turned off and on in a short time. In addition, electric infrared heaters can be programmed to provide heat-up and cool down cycles that suit products sensitive to overheating. Infrared emitters can deliver heat at low rates similar to a convection oven — or heat that is more than 20 times greater. Heating rates greater than 80 kW/m2 are seldom necessary although electric infrared can produce more. Electric infrared ovens can have multiple zones, each with a different heat profile. Independently controlled heating, drying and curing zones can be incorporated into a single oven.
Tip 4: Faster Speeds
Due to the faster heating rates and the high degree of control available with electric infrared process heating, most products can be heated faster than in a convection oven. Thus, it is possible to decrease the dwell in the oven and increase the throughput.
Tip 5: Increased Efficiency
The use of electric infrared may enable some manufacturers to make better use of their production facilities by delivering per-product processing costs that are comparable to, or lower than, those of a gas convection oven. Electric infrared will deliver a higher amount of input energy to the product than a gas convection oven. An electric infrared oven does not require a long startup time as might be required with a convection system. When infrared is the heat source, heat is delivered directly to the product and not into a carrier medium such as air. Infrared radiation can be directed to precisely heat only select areas of an assembly without overheating other areas that may be heat sensitive.
Tip 6: Compact Footprint
Electric infrared ovens tend to be more compact in size because electric infrared emitters deliver more heat to the product in less space than convection ovens. Production floor space can be better utilized.
Because heat delivered by infrared emitters is not dependent on convection (airflow), infrared ovens usually require much less insulation and bulky frames. Also, because there are no moving parts, there are no motors and motor supports for the heating components. Some manufacturers will hang infrared panels from the ceiling to save floor space.
Tip 7: Reliability
Electric infrared process heating systems tend to be reliable. With no moving parts or motors, they are, in most cases, modular. The ability to quickly heat up and cool down is important. For instance, in the time it takes a gas system to reach full temperature, an infrared system can be cooled enough to be worked on for maintenance.
Tip 8: Product Quality
Electric infrared energy emissions can be controlled, directionally directed, and temperature controlled more accurately than is possible in a convection oven.
For instance, infrared systems effectively heat materials such as coatings and paints that must be dried or cured. Infrared energy will penetrate the coating and warm the substrate material, flashing off the solvents quickly to eliminate bubbles and blistering. Infrared heating does not require convection currents to heat the product being manufactured; consequently, the uncured finish is not disturb by airflow — an effect found in convection ovens that can cause unpredictable or unacceptable finishes at times. Airborne particles are not deposited on the surface because the air turbulence in the oven can be limited to that of the products’ movement through it.
Tip 9: Versatility
An infrared oven or dryer’s operating parameters are versatile because most systems have short setup times, easy control of temperature and controllable speed. Consequently, many different products with different heat profiles and desired results can be run on the same manufacturing line.
Increases in line speeds that increase production rates usually are attainable by adding infrared modules. The length of most convection ovens is set to heat products for a particular time based on line speed through the oven or dryer. Many operations that have convection dryers add infrared to the input or output side to increase speed and production.
Tip 10: Environmentally Friendly
In today’s markets, manufacturers are increasingly required to adhere to regulations that limit the amount of emissions of solvents allowed to be freed into the atmosphere. Many manufacturers are replacing solvent-based coatings, adhesives and paint with water-based systems to comply with air quality standards. Usually, it takes longer to dry or cure water-based chemistries than to flash off solvents. Fortunately, electric and gas infrared heating can increase the rate of heating coated surfaces thereby recovering efficiencies lost in the switch to water-based materials.
Also, infrared heat processing systems will generate less heat into a surrounding air-conditioned work area, less noise emissions, and fewer noxious odors than convection systems.
While it makes sense to consider both infrared and convection systems, be sure to understand what advantages infrared heating can offer your process and company.John McKechnie, Anderson Thermal Devices Inc.
John McKechnie is Sales Manager at Anderson Thermal Devices Inc., Hawthorne, N.J., a manufacturer of electric infrared heat processing systems.
For more information, call (800) 720-5256 or visit www.andersonthermal.com.