Fenwal Controls of Japan, Ltd.

Tadayuki Shibuya

Masao Iguchi

Kanji Numao

Shintaro Masumoto

Takuya Ookawa

A photoelectric smoke sensor includes a housing having a circuit accommodation chamber, an inflow chamber provided in the housing, a light emitting portion provided in the inflow chamber, and a light receiving portion provided in the inflow chamber. The light emitting portion includes a first light and a first support portion surrounding the first light guide. The light receiving portion includes a second light guide and guiding the light to the light receiving element and a second support portion surrounding the second light guide. The first support portion and the second support portion are configured to prevent escape of a flame from the circuit accommodation chamber to the inflow chamber.

Photoelectric smoke sensor

Provided is an explosion-proofed photoelectric smoke detector capable of preventing the surrounding gas from taking fire generated by an explosion inside it and of eliminating filling spaces around a light-emitting device and a light-receiving device with resin, thereby checking explosions due to deterioration of the resin, which enables the detector to be used, with the devices exposed to gases in explosion-proof zones. The light emitting/receiving devices are arranged outside of an explosion-proof enclosure having a circuit compartment. They respectively have hollow cylinders A and B, light emitting/receiving elements, and light-guiding members A and B for transmitting emitted light and guiding received light, wherein a gap between the tube wall of each hollow cylinder and each light-guiding member and a length of each member between an opening formed in each cylinder and a light exiting/entering end thereof enable the devices to prevent fire generated inside the detector from leaking out thereof.

Photoelectric smoke detector

A photoelectric smoke sensor capable of detecting smoke with high accuracy is provided. The present invention relates to the photoelectric smoke sensor which detects smoke flowing into a housing by light. The present invention is provided with a light emitting element provided by being faced with a detection region in the housing and emitting inspection light to the detection region, a light receiving element provided at a position shifted from an optical path of the inspection light of the light emitting element by being faced with the detection region and receiving diffused light which is the inspection light having hit the smoke and diffused, so as to detect the smoke, and a reflecting member provided in the housing and deflecting and reflecting the inspection light emitted from the light emitting element so as not to enter the light receiving element.

The present invention can detect smoke with high accuracy. A light emitting portion is provided with a light emitting element outputting the inspection light with high brightness, the distribution of which is adjusted. A reflection portion collects the inspection light from the light emitting element to the detection region. A diaphragm portion transmits the collected light toward the detection region, while removing light diffused to regions other than the detection region a light shielding portion shields the light diffused to the regions other than the detection region. The light emitting element is provided with a light source outputting the inspection light with high brightness and a parabolic reflective mirror whose curved surface reflects light from the light source toward the detection region, the reflected light being in a doughnut shape in which the center is relatively dark and the periphery is bright.

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Tokyo, Japan

Tadayuki Shibuya