rutheb wrote:Does anyone know if this has copper inside the heating element? I read if it doesn't then it is not an infared heater.
Quartz heat lamps
Quartz infrared heating elements emit medium wave infrared energy and are particularly effective in systems where rapid heater response is required. Tubular infrared lamps in quartz bulbs produce useful infrared radiation in wavelengths of 1.5-8 microns. The enclosed filament operates at around 2500 K, producing more shorter-wavelength radiation than open wire-coil sources. Developed in the 1950s at General Electric, these lamps produce about 100 watts/inch (4 w/mm) and can be combined to radiate 500 watts per square foot (54000 watts/square m). To achieve even higher power densities, halogen lamps were used. Quartz infrared lamps are used in highly-polished reflectors to direct radiation in a uniform and concentrated pattern.
Quartz heat lamps are used in food processing, chemical processing, paint drying, and thawing of frozen materials. They can also be used for comfort heating in cold areas, in incubators, and in other applications for heating, drying, and baking. During development of space re-entry vehicles, banks of quartz infrared lamps were used to test heat shield materials at power densities as high as 28 kW/ square foot (300 kW/square meter).
Most common designs consist of either a satin milky-white quartz glass tube or clear quartz with an electrically resistant element, usually a tungsten wire, or a thin coil of iron-chromium-aluminum alloy. The atmospheric air is removed and filled with inert gases such as nitrogen and argon then sealed. In quartz halogen lamps a small amount of halogen gas is added to prolong the heater's operational life.
Much of the infrared and visible energy released is caused by the direct heating of the quartz material, 97% of the near infrared is absorbed by the silica quartz glass tube causing the temperature of the tube wall to increases, this causes the silicon-oxygen bond to radiate far infrared rays.
Quartz glass heating elements were originally designed for lighting applications, but when a lamp is at full power less than 5% of the emitted energy is in the visible spectrum.