摘要 |
In accordance with this invention, a misalignment detector apparatus is provided for a transmissometer with an underfilled reflector. The transmissometer has a transceiver that projects a collimated beam of light of small diameter across a smokestack to a circular reflector of substantially greater diameter than the collimated beam of light so that the reflector is underfilled. The reflector includes apparatus for sensing the position of the collimated beam of light with respect to the center of the reflector and its position on the reflector when it is not on center which allows operator notification of when the beam is on the reflector and when the beam is off the reflector thereby requiring maintenance/realignment.
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