Back to results
US 5,670,947 AGranted
Light scattering smoke sensor
AssigneeHochiki Corporation
InventorTetsuya Nagashima
Life of this patent
Estimating the term…
Abstract
In a light scattering smoke sensor of the present invention, a first diaphragm portion is disposed just aheat of a light receiving device, and a second diaphragm portion is disposed ahead of the first diaphragm portion. A gap between the first and second diaphragm portion is a smoke introducing portion which introduces smoke to a smoke detecting space via a gap between labyrinth members and the second diaphragm portion.
Claims8
A light scattering smoke sensor comprising:
- a housing defining a smoke detecting space therein, said housing having an opening for introducing smoke into said smoke detecting space;
- a plurality of labyrinth members located within said housing and substantially surrounding said smoke detecting space;
- light emitting means for emitting light to said smoke detecting space;
- light receiving means for receiving light scattered by smoke introduced into said smoke detecting space;
- first diaphragm means, which is disposed in front of said light receiving means, for defining a visual field of said light receiving means;
- second diaphragm means, which is disposed in front of said first diaphragm means, for defining a visual field of said light receiving means;
- and
- a cover member for covering said receiving means, in which said first diaphragm means is provided
- wherein said first and second diaphragm means defining a smoke introducing section therebetween through which said smoke passes as said smoke flows from said opening to said smoke detecting space.
6 more elements
Dependencies are inferred from the claim text.