| 摘要 |
<p>Particle detecting apparatus for detecting oil mist or other particulate matter comprises a measuring section (5) and an input/output section (6) which are removably attached together. A measuring chamber (60) receives gaseous fluid by diffusion from a receiving chamber (30) connected via an inlet (16) to an area being monitored. The measuring chamber (60) is defined by a cylindrical body (34) housing pairs of light emitting diodes (46A, 46B...) positioned diametrically opposite each other and directing light towards each other through a sampling volume (62) which is viewed by a photo-diode (52) through a viewing aperture (56). The photo-diode (52) detects light scattered by particles in the sampling volume (62). A glass tube (64) protects the LEDs (46A, 46B) from contamination and can easily be cleaned or removed and replaced. Each of the LEDs (e.g. 46A) can temporarily be de-energised in turn so as to act as a light detector, its output in response to light received from the opposite LED (e.g. 46B) being thus a measure of any contamination. The measuring and input/output sections (5, 6) can easily be separated for servicing or replacement.</p> |
