| 摘要 |
PURPOSE:To perform optical adjustment by providing one light shielding plate which has the apertures corresponding respectively to two IR detectors and is freely djustable in position and changing simultaneously the visual field of each IR detector by adjusting the position of the light sielding plate. CONSTITUTION:A light shielding plate 12 having two apertures A, B which correspond respectively to two detectors (a), (b) and have the area smaller than the area of filters 8, 10 is provided freely adjustably in position in the juxtaposing direction of the detectors (a), (b) by means of a spring 13 energized to return the same and a positional adjustment screw 14. While zero gas is run in a cell 1, the position of the plate 12 is adjusted to change the visual fields of the detectors (a), (b) simultaneously in the stage of maintaining roughly the same visual fields thereby offsetting the quantity of the background light radiated from the cell 1 and providing the optical balance of the two detectors (a), (b). While sample gas is flowed, an IR detector 7 detects only the radiation quantity radiated from the component of the measuring object among the IR light transmitted through the 1st and 2nd filters 9, 10. |
