What Materials Are Used In Tube Heaters?
Infrared radiant tube heaters are a simple, straight forward product. The theory behind how the system works is easy to understand and the excellent results speak for themselves. However, digging into the details of each unit’s construction is a great way to gather knowledge. In fact, considering the materials used to manufacture these systems will illuminate key components of each product’s functionality.
Re-Verber-Ray low intensity infrared tube heaters manufactured by Detroit Radiant Products use 16-gauge emitter tubes that measure 10′ in length by 4” in diameter. Commonly used by the infrared industry, 16-gauge emitter tubes represent the best balance between performance, responsiveness, safety and price. This type of tube hits the sweet spot of heating so the space will not be under or overheated while the unit fires.
Aside from the gauge of the tubes, there are also several material types from which the tubes are constructed. Each material adds a unique quality and is selected purposefully for each system. Let’s explore the various types of steel used to construct the emissive tubes:
- Hot-Rolled Steel: A common commercial grade ferritic steel that is heated to high temperatures then formed through a rolling die. This material is naturally dark in color, producing moderate emissive values. Characteristics of hot-rolled steel include low cost, limited corrosion resistance and lower heat tolerances.
- Aluminized Steel: A common hot-rolled steel that is coated with an aluminum-silicon alloy by the utilization of the hot-dip process. This alloy material is naturally silver in color, thereby reducing the emissive capacity of the finished product. This, in turn, warrants a special treatment for increased heat output. Characteristics of aluminized steel include higher cost, greater corrosion resistance and an increased heat tolerance.
- Titanium-Stabilized Steel: An enriched version of aluminized steel. The base metal, or substrate, is treated with a small amount of titanium to afford superior strength and heat tolerance. The aluminum-silicon coating is the same as the standard aluminized steel. Characteristics of this material include a superior ability to withstand vigorous cyclic service of higher temperatures, a greater corrosion resistance and a notable cost premium due to materials and availability.
- Stainless-Steel: A higher end commercial grade steel containing substantive amounts of chromium and nickel. The higher cost of stainless-steel limits its use to primarily harsh or humid environments where it exhibits superior corrosion resistance, however it is susceptible to warping at high temperatures due to reduced heat transfer properties. A titanium-stabilized 409 Series stainless-steel tube has a higher heat tolerance than the 304 Series, but can exhibit surface rust. Left without a highly emissive surface coating, both materials demonstrate lower output values.
While these differences may not seem like a lot, over time they make a huge difference for the life of the heater. For example, placing an infrared radiant system with Hot-Rolled or Aluminized tubes into a harsh environment may heat the space, but over the course of its life the heater will experience more corrosion and will likely need more maintenance. Meanwhile, using the less corrosive Stainless-Steel may be more expensive, but economically it is a better choice due to the heater being more resistant to damage.
Overall, there are four things to consider when selecting what type of emitter tube (and in relation, heater) is best for the application:
- Thermal Conductivity, or the ability to transfer heat through a material, allowing for a greater transfer of heat energy.
- Cost, which must be practical and economical without sacrificing quality.
- Corrosion Resistance, especially important in harsh environments.
- Emissivity, or the ability of the heat exchanger to efficiently release heat in the form of radiant energy.
Great Lakes Radiant & Industrials has experts on staff who are ready to discuss your next infrared radiant heat project. As part of the consultation, we assist with product selection to ensure each space is heated properly. During the discovery process, we will ask questions to determine which unit is right for the space, taking into consideration the various properties and materials mentioned above.
For more information, or to speak with someone about finding a solution for your tough-to-heat space, give us a call at 888-501-0252 or email [email protected] today!