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Frequently Asked Questions
Here are the answers to the most commonly asked questions at Solar Products.

Question No. 1

Can Solar Products' heaters be attuned to an appropriate wavelength?


ll infrared heaters have the ability to be attuned to a specific wavelength. The infrared wavelength produced by a heater is inversely proportional to the heater's output temperature.

Electric heaters have an infinite ability to be adjusted within heater temperature limits. This permits a greater amount of flexibility for matching a heater's output with a industrial application's requirements. Gas heaters, on the other hand, have less capability for adjustment. Generally, the output produced by a gas heater can range from 100 percent to 70 percent. Below that point, gas heaters will usually shut off. 

Many professionals think that an optimal goal is to match the output wavelength of a heater with a product's absorption. Although it can be a good starting point, this principle is not always helpful. Short, medium, and long wavelength heaters can often be used for most applications. Generally, shortwave heaters will heat, cure, or dry the product in the shortest amount of time, mediumwave heaters will take slightly longer, and longwave heaters will require the most time. Certain factors can, however, make the above statement incorrect. An example is the process of heating a white plastic sheet, common in thermoforming applications. Because shortwave infrared is color sensitive, black colors will quickly absorb shortwave infrared, but white colors will reflect a much larger amount of the energy. In this case, a mediumwave heater can actually heat a white sheet of plastic faster than a shortwave heater. Because of this tendency, testing is the only way to effectively determine the results.

All heaters currently in use worldwide do not output their energy at a single wavelength. Rather, every heater's output energy distributes across multiple wavelengths, although it usually has a peak wavelength that relates to the emitter's temperature. (25% of the energy is at a shorter wavelength than the peak and 75% of the energy is at a longer wavelength than the peak). A number of factors affect a decision to determine which wavelength emitter is appropriate. These considerations include the initial cost of the system, operating cost, available space, process speed, and maintenance costs.

The choice of Solar Products' panel heaters for industrial applications is due to their high radiant efficiency (typically 80%), long life (25,000 hours), durability, flexibility in available sizes, and temperature uniformity.

Question No. 2

Does infrared energy penetrate a sheet of plastic?


Infrared heat does penetrate a sheet of plastic within certain limits. Studies have previously shown that infrared energy will penetrate it up to .015 inches. Past that point, the sheet is only heated via conduction. The real penetration amount will depend, however, on a number of influential variables, such as heater output energy, wavelength, sheet type, sheet characteristics, and sheet color.

Heat cycle times depend on the sheet's conduction and the amount of power that it can absorb before its surface begins to overheat and possibly burn. When ABS plastic (acrylonitrile-butadiene-styrene) and HDPE plastic (high density polyethylene) are compared, we have found that ABS will burn at a much lower temperature than HDPE. For this reason, the heater temperature for ABS applications typically does not exceed 800°F. On the other hand, when a sheet of HDPE is heated, the temperature of the heaters can be raised to 300 to 400°F without causing any damage to the sheet's surface. This increased temperature permits more energy to be absorbed by the sheet. HDPE is a crystalline material that requires more energy to heat the sheet than ABS, an amorphous material. The ability to raise the temperature higher with HDPE is important because it reduces the heating cycle time. Even with more power, HDPE typically needs one second per mil to be heated, whereas ABS can be heated in .5 seconds per mil. The heating rate for ABS is accomplished with a lower heater temperature, and, therefore, a lower energy output. The above considerations are only general rates for heat transfer, however. The rate of heat transfer will increase as the sheet's thickness decreases, and decrease as the sheet's thickness increases. In other words, heating cycle times are proportional to the square of the sheet's thickness.

Question No. 3

What size heaters does Solar Products offer?


The choice of a heater's size depends on the type of heater required for a given application. The F-Series model is our most commonly produced heater because of its high radiant efficiency (typically 80%), long life (25,000 hours), durability, flexibility in available sizes, temperature, and uniformity. Heaters in the F-Series product line can be constructed in standard sizes between 6" and 12" wide and 6" increments in length up to 60" for the 6" wide heater and up to 84" for the 12" wide heater. Because we are a custom manufacturer of heaters, both the heater's length and width can be customized to your exact requirements within good engineering limits. The width can be constructed from 3" to 30", and the length can be constructed from 6" to 84", though we prefer not to build a heater 30" x 84" because of its reduced durability.

Our G and M series of glass and metal face heaters have more limits on their lengths and widths. Glass face heaters typically are not longer than 36", and metal face heaters are usually not longer than 48".

Our Q-Series heaters are restricted further in size. Because of a limit on the size of the quartz used to build the heaters, the Q-Series heaters are commonly built in smaller sizes, such as 6" x 12" and 12" x 12". Q-Series heaters have been manufactured in sizes up to 15" x 16".

Note: The size limits for all the heaters mentioned above will vary depending on the particular application requested. The sizes given are only intended to be general guidelines to abide by.


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