Optical energy radiated from fuel flame in boiler so far is widely use for furnace flame detection. Most of the flame detectors are of infrared type both in China and abroad.

利用炉内燃料燃烧过程中火焰辐射的光能监测炉膛火焰是目前应用的最广泛的方法，红外线火焰监测器在国内外应用最广。

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With its far-infrared detectors, Herschel has been able to re-visit familiar objects to provide new data.

BBC: Herschel space telescope to go blind