Patent ID: 6914535
Filing Date: 2005-07-05
Classification: G08B

Abstract:
1. A light scattering type smoke sensor comprising: a sensor main body; a cover defining a smoke detection chamber within and said cover having a plurality of smoke influx entrances around the periphery for introducing smoke particles into said smoke detection chamber; a plurality of labyrinth members located within said cover and substantially surrounding said smoke detection chamber for obstructing direct light from crossing said labyrinth members to said smoke detection chamber; a light emitting part for emitting light toward said smoke detection chamber formed by said labyrinth members; a light detecting part for receiving light scattered by said smoke particles from said light emitting part in said smoke detection chamber; a holder for establishing an unrestricted scattering angle θ so there is no directivity to said smoke particles introduced to said smoke detection chamber which is situated in said sensor main body at the upper part of said smoke detection chamber; wherein said holder includes openings oriented at opposite facing sides for embedding said light emitting part and said light detecting part without protruding into said smoke detection chamber; wherein said holder is constituted with said light emitting part and said light detecting part mounted in fixed positions so that the optical axis from said light emitting part which faces said smoke detection chamber and the optical axis of scattered light that is dispersed by said smoke particles in said smoke detection chamber which faces said light detecting part intersect at a predetermined horizontal plane first angle α and intersect at a predetermined vertical plane second angle β.