| 摘要 |
An automatic setup backscatter particulate monitor includes a small source (38) of narrow beam radiant energy directed into a gas stream containing particulates. A lens (34) that is mounted behind the radia nt energy source (38) collects the energy reflected back from the particulates and concentrates it on a photodetector (48). The beam is directed into the duct at an angle greater than twice the beam spread, minimizing reflection off opposing wall surfaces. Internal radiant energy sources are periodically directed to the detector to verify system integrity. Backscattered energy is corrected for energy reflected fro m the opposite stack wall and for ambient energy.
|
