Hochiki Corporation

Hochiki Kabushiki Kaisha

Tosoh Corporation

Naoki Kosugi

Masayuki Ito

Tetsuya Nagashima

Yasuo Torikoshi

Toshiyuki Mori

Hiroshi Yamamura

Hiroshi Sawa

Hirokuni Hoshino

Yoshiki Ohmori

Hironobu Kawai

It is prevented that a malfunction occurs because of a noise. A smoke detection section samples as a smoke detection signal a signal digitized after being output from a light reception section when a light emission section glows, and updates a previous smoke detection signal. A noise detection section samples as a noise detection signal a signal output from the light reception section when the light emission section is not driven to glow. When the noise detection signal exceeds a predetermined noise level, a noise de-influence unit disables updating of the previous smoke detection signal with the newly sampled smoke detection signal so as to process a noise.

Fire detector and noise de-influence method

A multi-sensor type sensor has sensor processors for generating detection data of plural types based on detection signals from a plurality of sensor portions, and a mode switching portion for switching a mode which indicates type of data to be sent to a receiver in response to a mode switching instruction issued from the receiver, and sending selectively the data of the type which corresponds to a current switching mode in response to a data request instruction issued from the receiver. The receiver includes a mode switching indicating portion for switching the mode by transmitting the mode switching instruction which selects type of response data to the fire sensors, and a fire judging portion for judging the fire by receiving the response data from the fire sensors in response to transmission of the data request instruction.

Fire monitoring system and fire sensor

A temperature difference calculator portion detects temperature difference indicating the rate of temperature rise when it receives heat generated by the fire. A correction factor deciding portion decides a correction factor for a smoke signal based on an external temperature and the temperature difference. Finally, a smoke data correction portion corrects smoke data by multiplying the smoke signal detected by a smoke detector and the correction factor.

Fire sensor and fire detecting method

A drive pulse for emitting and turning-off a light emitting element is output, the level difference or the level ratio between the light emission zero point detection signal from a light receiving element having received the light from the light emitting element and a putting-off zero point detection signal from the light receiving element when the light emitting element is put off is calculated, and the level difference or the level ratio is compared with a preset level to thereby determine the abnormality of the light emitting element, the light receiving element and a peripheral circuit. With this arrangement, even if the ratio of noise light occupied in the zero point output is reduced, whether detecting elements and the peripheral circuit are good or bad and whether the elements are abnormally polluted or not can be reliably tested without the effect of the dispersion of the detecting elements and the change of an ambient temperature, whereby the reliability of a smoke detector is improved.

Photoelectric smoke detector and disaster monitoring system using the

A fire disaster monitoring system of the present invention has a control unit and a fire sensor. The fire sensor includes a sensor base and a sensor body. The sensor base incorporates a first memory which stores first address information of the first memory. The sensor body incorporates a second memory and a CPU therein. The second memory stores second address information of the sensor body. The CPU includes an address reader, a comparator and an address generator. When the power is turned on, the address reader reads the address information in the first memory, and reads the address information in the second memory. The comparator compares the read pieces of address information with each other. When the comparison result by the comparator indicates agreement, the address generator leaves the address information in the second memory as valid data. On the other hand, when the comparison result indicates disagreement, the address generator writes the address information in the first memory into the second memory.

System for monitoring disaster prevention

A photoelectric sensor of the present invention includes a light emitting device and a light receiving device for detecting scattered light due to smoke, a light emitting confirming device which lights up when a quantity of light received by the light receiving device is greater than or equal to a threshold and a test light emitting device for emitting light to the light receiving device during the test, wherein a blinking of the light emitting confirming device is started at a time of a test start, and a quantity of light received by the light receiving device is increased in steps so that the blinking is stopped when the quantity is greater than or equal to the threshold. Accordingly, the sensitivity test can be performed by visually counting the number of blinkings of the light emitting device.

Photoelectric smoke sensor and fire detecting system, and sensitivity

A thin-type photoelectric smoke detector which is less susceptible to the effect of disturbance light noise, contamination of a smoke detecting unit, etc., and which ensures high sensitivity for the optical detection characteristic of the smoke detecting section. In the photoelectric smoke detector of the type in which infrared light is irradiated into a flat smoke detecting chamber and the scattered light of the irradiated infrared light due to smoke entering into the smoke detecting chamber is detected by a light-sensing element, there are provided optical members for expanding the visual field of the light-sensing element to a flat visual field corresponding to the cross-sectional shape of the smoke detecting chamber.

Photoelectric smoke detector with expanded visual field

A method for preparing zircon powder, which comprises mixing (1) silica sol and (2) an aqueous zirconium oxychloride solution having a concentration which would be from 0.1 to 2 mols/l after mixed with the silica sol, in a SiO.sub.2 /ZrO.sub.2 molar ratio of from 0.95 to 1.10, heating the mixture to hydrolyze the zirconium oxychloride, followed by dehydration treatment to obtain a powder, heating the powder from room temperature to a calcination temperature over a period of from 0.7 to 30 hours and calcining the powder at a temperature of from 1,200.degree. to 1,400.degree. C. for a period of time satisfying the relation of:

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Tokyo, Japan

Naoki Kosugi