Fenwal Controls of Japan, Ltd.

Kanji Numao

Masao Iguchi

Tadayuki Shibuya

Shintaro Masumoto

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

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.

Light emission portion, photoelectric smoke sensor, and suction-type smoke sensing system

A photoelectric smoke detector may detect presence of smoke by utilizing a light emitting element and a light receiving element whose optical axes intersect with each other. The photoelectric smoke detector may include a casing for storing the light emitting element and the light receiving element. Inlet and outlet ports may be respectively provided in one and the other sides of the casing, the inlet and outlet ports bringing air flow into the casing. Rectifying light blocking means may be provided contiguously with each of the inlet and outlet ports, the rectifying light blocking means preventing entry of disturbance light into an interior space and forming a flow line of smoke extending from one or the other inlet and outlet port to the other or the one inlet and outlet port such that the flow line passes through a detection area by the light emitting element and the light receiving element.

A photoelectric smoke detector is provided which is suitable for being downsized without detection capability deterioration. The present invention relates to a photoelectric smoke detector for detecting presence of smoke by utilizing a light emitting element and a light receiving element whose optical axes intersect with each other. Then the photoelectric smoke detector has: a specialized labyrinth function fulfilling part for playing only a labyrinth function of bringing air flow into an interior space thereof and preventing entry of disturbance light into the interior space; and a smoke detecting part which is provided above the specialized labyrinth function fulfilling part so that an interior space of the smoke detecting part is communicated with the interior space of the specialized labyrinth function fulfilling part, and which has the light emitting element and the light receiving element built therein and has a small hole for extracting air flow that has passed through a detection area near an intersection between the optical axes of the light emitting element and the light receiving element.

Growing community of inventors

Tokyo, Japan

Kanji Numao