| 摘要 |
The subject of the invention is the addition of a static filter system called "parasitic electromagnetic radiation rejector", to a receiver R which is part of a transmitter E/receiver R assembly, for progressive-opacity smoke detection. The internally reflecting rejector, in the shape of a truncated cone or truncated quadrilateral pyramid, concentrates the electromagnetic radiation reaching it axially from the transmitter E, whilst rejecting non-axial undesirable parasitic radiation. Referring to the figure, 1 is the rejector seen from the inside, 2 is the external view thereof, in the form of a template which is inscribed exactly in the casing 9. The photosensitive cell is represented at 4, the identical side platelets at 5-6, the top and bottom platelets at 7-8, the heel piece (shank) 3 providing centring in the direction of the height of the rejector with respect to the photosensitive cell of the receiver. <IMAGE> |
