| 摘要 |
PURPOSE:To facilitate the mounting of a exhaust pipe securing the maximized S/N ratio of a smoke density sensor, by arranging a projecting section and a light receiving section integral in a head to align the optical axis of the measuring optical path optimum. CONSTITUTION:A light emitting/receiving head 10 is connected to an LED 50 and a photodiode 52 through a cable 48 with a connector 46. A groove is provided on the circumference of a casing 12 near the outside end thereof and a connector 46 is snapped. The cable 48 is provided with optical fibers 54 and 56 connected to respective photoconductors 30 and 32 to return light beam from the LED50 to the diode 52 across a measuring gap comprising a notch 28. These head 10, cable 48 LED 50 and diode 52 compose a smoke density sensor. The light beam is absorbed according to the density of the smoke of an exhaust gas flowing through the measuring gap and the smoke density is detected according the ratio between the incident light and the transmission light with the diode 52. |
