| 摘要 |
PURPOSE:To prevent adverse influence of the destruction of a photodetecting member to be inflicted upon a system to be measured by providing a frame member which covers the flank of a photodetecting member which transmits the combustion light in a combustion chamber to the outside and part of a photodetection surface. CONSTITUTION:The frame member 2 convers the flank of the photodetecting member 1 made of a quartz glass rod which has excellent heat resistance and pressure-tightness and high photoconductivity and the part of the periphery of the photodetection and surface 1a which is exposed in the combustion chamber. The frame member uses a metallic material which is transparent, firm, and easily worked so as to prevent external light from entering the photodetecting member 1 and also protect said member against a mechanical shock. Consequently, even if the photodetecting member 1 is broken, none of its broken pieces falls out of the frame member 2 and abnormality of the flame sensor itself does not exert any influence upon the system to be measured. |
