Reflectors installed behind quartz emitters direct infrared energy toward the product -- unless they’re too dirty to operate effectively.

Many electric infrared ovens rely on quartz medium-wave or short-wave infrared emitters to impinge heat on the product. Reflectors installed behind the emitters are therefore necessary to direct the infrared energy efficiently toward the product. Reflectors designs vary in patterns or composition, but all are designed to allow for ease of maintenance and cleanliness.

While air is virtually transparent to infrared radiation, water vapor, dirt, dust and paint overspray that fall on the infrared element or reflector will absorb infrared radiation. Both infrared and convection ovens require regular preventive maintenance. Maintenance of infrared ovens includes examination of the emitters and replacing any that have failed. In addition, regular cleaning of reflectors in electric infrared ovens will help maintain efficiency.

To understand the importance of reflector cleanliness, you need to look at what reflector maintenance means to the overall efficiency of the electric infrared oven. Most industrial infrared ovens are designed around the customer’s specific needs and application. This makes it difficult to define “oven efficiency” in generalized terms that can be applied to every situation. However, an industry-wide accepted definition for oven efficiency is that it is equal to the amount of energy absorbed by the product divided by the total energy consumed by the oven.

Efficiencies measured on various infrared ovens will vary in the range of 10 percent to 70 percent. The main factors that affect infrared oven efficiency are oven design; product (surface characteristic, geometry and position to infrared); reflectors (including reflector design and cleanliness); and exhaust and cooling system design and operation.

The following example illustrates the importance of reflector maintenance. Assume a typical, well-designed, well-maintained infrared oven operates with efficiencies in the 25 percent range. (This means that in order to put 1 kW/hr of energy into the product, you will have to buy 4 kW/hr of electricity.) With dirty or damaged reflectors, the oven efficiency could possibly fall to 20 percent. This means that to do the same job as before, you now have to buy 5 kW/hr of electricity -- assuming the oven has the capability. Therefore, what appears to be a slight reduction in efficiency (only 5 percent) causes a significant increase in power consumption (25 percent). This is why regular maintenance and cleaning of an infrared oven is extremely important.

In addition, heat sources should be kept as clean as the reflective areas of the equipment. If the heat sources become dirty, this will cause overheating and reduce their efficiency and reduce their expected life. To clean the quartz envelope, wipe it off with a cloth dampened with alcohol, then follow with a soft dry cloth. Do not touch the lamp with bare hands after cleaning.

Some ovens and control panels are equipped with filters. Filters should be periodically checked and changed as soon as they become dirty. Of course, determining how often the oven should be cleaned will depend on shop conditions.

10 Tips: Quartz Infrared Heaters

  1. Infrared oven maintenance includes regularly examining the emitters and replacing any that have failed.

  2. Regular reflector cleaning will help maintain efficiency.

  3. Develop a maintenance schedule that includes checking the operation of all heat sources.

  4. Keep all dust, dirt and paint overspray away from the oven openings.

  5. Heat sources should be kept as clean as the reflective areas of the oven.

  6. If heat sources become dirty, they may overheat and experience a reduction in operating efficiency.

  7. When cleaning any reflective surface, blow away all loose dirt and dust; then wipe the reflectors with a clean, soft cloth or other a nonabrasive material.

  8. To clean the quartz tube infrared lamp or quartz lamp heat source, don gloves. Then, wipe the lamp with a cloth dampened in alcohol, followed by a soft, dry cloth.

  9. Do not touch the emitters with bare hands after cleaning.

  10. Some infrared ovens’ emitters provide a nearly instant response with virtually no warmup time required.

Fostoria Industries