| 摘要 |
In a photoelectric smoke detector of the type wherein the quantity of light incident upon a light receiving element from a light source is varied in accordance with the concentration of the smoke to be detected thereby producing an electric signal, there are provided a light shielding member for preventing the light from the light source from impinging directly upon the light receiving element and an adjusting screw located near top of the light shielding member for adjusting the quantity of the light projecting to the detection region from the light source and the quantity of the reflected light impinging upon the light receiving element from the smoke. |
