Abstract: Embodiments of the present disclosure relate to a flame detector. The flame detector comprises a light guide system including a first end and a second end opposite to the first end, a light path being formed between the first end and the second end and extending along an optical axis; a first hole disposed at the first end, extending along the optical axis and forming a part of the light path, the first hole being configured to receive light emitted by a flame to be detected; and a second hole disposed at the second end, extending along the optical axis and forming a part of the light path, sizes of the first and second holes and a length of the light path being configured such that a detection angle of the light guide system is between 0.5 degrees and 3 degrees.

Abstract: Embodiments of the present disclosure relate to a flame detector. The flame detector comprises a light guide system including a first end and a second end opposite to the first end, a light path being formed between the first end and the second end and extending along an optical axis; a first hole disposed at the first end, extending along the optical axis and forming a part of the light path, the first hole being configured to receive light emitted by a flame to be detected; and a second hole disposed at the second end, extending along the optical axis and forming a part of the light path, sizes of the first and second holes and a length of the light path being configured such that a detection angle of the light guide system is between 0.5 degrees and 3 degrees.