Patent ID: 8232885

Claim:
A photoelectric smoke detector comprising: a smoke detecting unit; and a fire determining unit for determining, based on a signal output from the smoke detecting unit, whether or not a fire has occurred, the photoelectric smoke detector outputting a fire signal when the fire determining unit determines that the fire has occurred, wherein the smoke detecting unit comprises: an installation section; and a smoke inlet section, wherein the installation section comprises: a light emitting element for emitting light to an inside of the installation section; and a light receiving element for receiving the light which is emitted from the light emitting element and scattered by smoke particles within the smoke detecting unit, wherein the smoke inlet section comprises: a plurality of wall members for preventing external light from entering the smoke inlet section; and a smoke inlet formed between the plurality of wall members, and wherein a smoke detecting region is defined in the installation section, wherein the installation section and the smoke inlet section are arranged so as to overlap each other, with the smoke inlet section being positioned on a lower side of the installation section when the photoelectric smoke detector is installed on a ceiling of a monitor space, wherein the smoke inlet section further comprises a partition wall having an opening through which the smoke inlet section is communicated with the installation section, wherein the partition wall has a lower surface that has the plurality of wall members formed thereon, and that has an inclined surface which inclines upwardly in a direction toward the opening so as to guide smoke flowing into the smoke inlet section through the opening into the installation section, and wherein an angle of the inclined surface and an inner diameter of the opening are set so that the smoke flowing along the inclined surface of the partition wall is guided to the smoke detecting region defined in the installation section.