Hochiki Corporation

Hochiki Kabushiki Kaisha

C. Hochiki Corporation

Yukio Yamauchi

Hiroshi Shima

Kari Mayusumi

Shigeru Ohtani

Takeshi Tanigawa

Ichiro Endo

Hiromitsu Ishii

Hiroshi Sawa

Tadashi Sugiyama

Tetsuya Kubo

Hiroyuki Kitta

Hiroshi Homma

Atsushi Manmoto

Kentaro Ito

A fire sensor comprising a baseplate, a temperature detecting element, and a protective case. The baseplate has an outside surface which serves as a heat sensing surface which is exposed to a hot airflow generated by a fire. The temperature detecting element thermally contacts with the inside surface of the baseplate to detect the temperature of the baseplate. The protective case contacts with the radially outer portion of the inside surface of the baseplate to form a hermetically sealed space between itself and the baseplate. The temperature detecting element is confined within the hermetically sealed space. The baseplate has the temperature detecting element in approximately the central portion of the inside surface thereof and also has a shape and a material which meet the condition that the product of the thickness and heat conductivity of the baseplate is 1.1&#xd7;10(W/K) or less.

Fire sensor

A fire heat sensor comprising a high-temperature detecting portion provided with a temperature detecting element which exhibits a fast heat response to a rise in ambient temperature, and a low-temperature detecting portion provided with a temperature detecting element which exhibits a slow heat response to a rise in ambient temperature. The fire heat sensor further comprises a resin member by which the high-temperature detecting portion and the low-temperature detecting portion are integrally formed so that heat energy is transferred from the temperature detecting element of the high-temperature detecting portion to the temperature detecting element of the low-temperature detecting portion. In the fire heat sensor, differential heat sensing is performed based on temperatures detected by the low-temperature detecting portion and the high-temperature detecting portion.

Fire heat sensor

A fire sensor comprising a heat detection element for detecting heat from a hot airflow generated by a fire, a sensor main body, and an outer cover, which has a plurality of plate fins protruding from the sensor main body, for protecting the heat detecting element. The plate fins have a predetermined offset angle to a center line passing through the center of the outer cover and are erected approximately perpendicular to the sensor main body.

A light source image, i.e., a near field pattern of the light-emitting face of a laser diode which emits laser light having the electric field component in a predetermined direction is formed by an imaging lens at an image forming position of a smoke detecting area through which a flow of sucked air passes. A light receiving device is disposed on an optical axis which passes through the image forming position of a light source image in the smoke detecting area and which is set in a plane that is substantially parallel to the direction of the electric field component of the laser light, and receives scattered light due to a smoke particle passing through the imaging position of the light source image and the vicinity of the imaging position.

Smoke detecting apparatus with a predetermined direction electric field

The pulse width of a light reception pulse signal a from a light receiving device is detected, and the smoke density is detected based on a total pulse width of pulse widths per unit time period. Alternatively, the smoke density may be detected based on an integrated value of the light reception pulse signal a from the light receiving device per unit time period. Even if the flow rate of the sucked air is varied, the total light reception pulse width value per unit time period is not varied, so that the smoke density can be accurately detected.

Smoke detecting apparatus utilizing light signal pulse widths

A light emitting device for projecting a light beam onto a monitor area, and a light receiving device, arranged so that a light beam is not directly received by the device, for receiving diffused light caused as a result of fine particles, such as dust, or smoke caused by a fire, entering the monitor area, are provided. Also, an amplifying device for amplifying an output from the light receiving device, and a counting device for counting the output from the amplifying device in units of time are provided. In addition, a computing device for computing an average value or an integrated value of the output from the amplifying device in units of time, and a determining device for determining the level of contamination of the monitor area on the basis of the count value of the counting device and for determining the level of the fire on the basis of the average value or the integrated value computed by the computing device, are provided. As a result, a smoke detecting apparatus consisting of a single unit capable of detecting both smoke and fine particles can be provided, the apparatus detecting a fire on the basis of an environmental abnormality.

Smoke detecting apparatus capable of detecting both smoke fine particles

First sensors measure physical quantities correlated with the heat release value of a fire source, and second sensors measure physical quantities correlated with the amount of the product of burning. At least a pair of one first sensor and one second sensor are arranged in a zone to be monitored. A first threshold of high sensitivity and a second threshold of low sensitivity are set at the first sensors. A third threshold is set at the second sensors. A pre-alarm is given only when the level of signals from the second sensors exceeds the third threshold. A fire alarm is given when the level of the signals from the second sensors exceeds the third threshold and when the level of signals from the first sensors exceeds the first threshold. The outputs from a plurality of such sensors detecting different objects, such as heat and smoke, are processed in the manner in which these outputs are combined together to reliably detect fires and to give a fire alarm. It is possible to improve the accuracy of detecting fires, and to reduce the incidence of false alarms.

Combined method of determining fires

A fire discriminating apparatus for determining whether there is the outbreak of fire in an area under surveillance in accordance with the temperature difference between a temperature detection value of the area and a reference temperature. The apparatus includes a temperature sensor for detecting an ambient temperature; sampling means for sampling the detected temperature of the temperature sensor at a given period, temperature difference detecting means for computing a temperature difference between the detected temperature and a reference temperature each time the detected temperature is sampled by the sampling means, fire discriminating means whereby when the temperature difference is greater than a predetermined threshold value the outbreak of a fire is determined and an alarm command signal is generated, and reference temperature correcting means whereby a correction value obtained by multiplying the temperature difference obtained upon each sampling by a given factor smaller than 1 is added to the reference temperature to correct the reference temperature for the detection of temperature difference during the next sampling.

Fire discriminating apparatus

A fire alarm system which makes fire determination based on a novel idea which considers various changes of the physical phenomena in the surroundings caused in relation with the occurrence of a fire in terms of changes of vectors. These changes in the physical phenomena are detected by the detecting section in the form of analog data and processed by a data sampling section as sampled data and stored in a storing section in such a manner as discriminating them by the detecting sections. The tendencies of the changes are computed in a first computing section and the vectors representing the present or future conditions of the physical phenomena are computed from the sampled data. The vector is compared in a comparing section with a preliminarily set data related to the fire detection and when the relation therebetween is not a predetermined one, an alarm is given through an alarming section.

Fire alarm system

A gas sensor and a method for detecting a small amount of a gas such as CO contained in air entering a space between electrodes ionized by a radiation source. At least one radiation source is provided for ionizing at least a part of the space between the electrodes disposed so as to oppose each other and a radio d/x of a distance d cm between the electrodes to a field strength x V/cm of the ionized space is set to be 0.4 or more so as to obtain a change in the ionic current sufficient to realize gas sensing based on the formation of cluster ions within the ionized space.

Gas sensor and gas detecting method

A gas sensor comprising a device by which photo absorption is changed in the presence of hydrogen gas or hydrogen containing compound gas and an optical detecting means for detecting the change of photo absorption. The device is provided in the form of a laminate made of a metal adsorbing and dissociating hydrogen or hydrogen containing compound gas and a solid compound which is reduced by hydrogen atoms produced in the metal to change photo absorption.

Gas sensor

A temperature detecting apparatus having a first transistor connected in diode configuration or a first diode, with its forward current set in certain value. A second transistor has similar electrical characteristics as the first transistor or the first diode, with the anode or cathode of the first transistor or the first diode being connected to the base of the second transistor. The temperature difference between the first transistor or the first diode and the second transistor is detected by means of the variation of the collector current of the second transistor. In another embodiment, a third transistor matched to second one is used with common base connections. The first transistor is coupled to the common base coupling.

Temperature detecting apparatus

A temperature detecting device having rapid temperature sensing characteristics and with a fully protected temperature sensitive element. A transistor pellet potted in a resin casing having at least one thin wall is mounted in a metal protective tube in thermal contact provided through a small amount of filler material of high thermal conductivity. A heat collector is disposed around the protective metal tube in close thermal contact therewith. The edges of the heat collector are held in position against ribs formed on an insulating casing by engaging members of a protective ring which fit into corresponding notches formed in the upper portion of the ribs. Protrusions formed on the protective member prevent its rotation and removal hence making the device essentially tamperproof.

Temperature detecting device

A monitoring system having physical condition detectors arranged at places remote from a central receiving device so as to detect changes in the physical condition of a matter to be observed such as temperature, light and smoke. The central receiving device impresses detection mode signals on the output portions of detectors to control the outputs thereof. When said receiving device receives an output fed from said detectors by one of detection mode signals, said receiving device displays a physical condition of matter responding to the detection mode signal, thereby enabling the physical condition of matter to be continuously observed responding to detection mode signals and according to the lapse of time.

Physical condition monitoring system for detection in remote places

In response to oscillator output pulses, a sample pulse generator supplies sample pulses to a fire sensor. In response to the sample pulses, the fire sensor produces a fire sensor signal. A judging circuit receives the fire sensor signals and, if they exceed a predetermined level, produces a judging pulse having a longer pulse duration than the oscillator pulses. This judging pulse is used to trigger an alarm signal. A monitor circuit consists of an AND gate and an OR gate. The AND gate receives as inputs the oscillator pulses and the judging pulses. The OR gate receives as inputs the output of the AND gate and the sample pulses. The output of the OR gate constitutes a monitor pulse that allows the simultaneous monitoring of three conditions, as follows:

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Kanagawa-ken, Japan

Yukio Yamauchi