Abstract: A fire alarm system comprises a first light emitting device (11), a first polarizing filter (31), a first light receiving device (21), a second light emitting device (12), a second polarizing filter (32), and a second light receiving device (22). With the above arrangement, the amount of the parallel polarized component to the scattering plane as well as the amount of the perpendicular polarized component to the scattering plane is detected. The ratio between these amounts of light has a correlation with the type of smoke. A calculation section (4) calculates this ratio from the outputs of the light receiving devices (21, 22). A decision section (6) compares the above-described ratio with a reference value which has been preset according to the type of smoke to be detected, whereby the judgement of whether there is a fire or not is performed depending on the type of smoke. Thus, the detection of a fire can be performed from the light scattered by smoke taking into account the type of smoke.

Abstract: A transmission data synchronization system in a disaster prevention monitoring system comprises the steps of: connecting a plurality of terminal units to first and second transmission lines led out from a receiver; sending out access data in the form of a voltage from the receiver through the first transmission line; and sending back response data by a terminal unit specified in the access data in the form of an electric current through the second transmission line during a response time period. The response data sent back by a terminal unit which has responded to the access data sent out by the receiver is formed of terminal state data and checksum data produced by adding the terminal state data to the self-address data. The receiver adds the address data to the terminal state data, and determines that a transmission error has occurred when the data determined from the addition does not match the checksum data.

Abstract: 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.

Abstract: A thermal analog fire detector which is excellent in measurement precision and resolution in both the high and low temperature ranges and which has a wide range of measuring temperatures. A constant voltage E from a constant voltage circuit is supplied to a CPU, an A/D converter and a constant current circuit. The constant current circuit is connected in series to a thermistor. The constant current circuit is constructed to supply a constant current, the value of which being variable in a plurality of stages, to the thermistor controlled by the CPU. The CPU switches the constant current of the constant current circuit according to the measured temperature data. A voltage V across the thermistor is converted into digital data by the A/D converter, and then the converted data is supplied to the CPU.

Abstract: During data transmission between a receiver and each of terminal devices in a disaster prevention supervisory system, the receiver sends calling data including address data for specifying a specific terminal device to the side of terminal devices in a transmission error detection mode. The receiver also causes the terminal device specified by the address data to return error detection response data including self-address data and check data for a current level previously defined. When the current level of the check data in the error detection response data received by the receiver is higher than the level previously defined due to the response of a plurality of terminal devices, it is decided that an abnormality is present in the terminal device of the address specified by the calling data.

Abstract: A radio analog sensor for transmitting analog signals of a temperature or smoke density to a remote place by radio is used as each of sub devices 12-1 to 12-n. When a change of the analog detection signals of a temperature, a smoke density or the like, which is detected by the analog sensor 10 connected to each of the sub devices, is greater than a predetermined value, the analog signals which have been so far stored in a memory are collectively transmitted to the receiver side by radio. Periodic information is also sent from each of the sub devices 12-1 to 12-n once every two hours so as to supervise the state of the sensors. This permits reliable transmission of necessary data to a remote place without decreasing the life of the battery.

Abstract: A thermal detector comprises: an element unit 11 having a heat sensor element 1 such as a thermistor sealed into the terminal end portion thereof, for electrically detecting temperature change; a detector body integrating by means of plastic-forming a pair of fitting members 12 for electrically and mechanically coupling to a detector base; a circuit board 16 mounted on a circuit accommodation portion 15 inside the detector body; and a back side cover 17 for closing and sealing the circuit accommodation portion 15 from the reverse side thereof. Thereby, airtightness of the circuit accommodation portion is secured and it is simplified to make possible automatization thereof. Also, positioning projections 110, 112, 114 and positioning grooves 111, 113, 115 are provided. By respectively fitting these, positioning of the circuit board 16 to a molded body 14, the back side cover 17 to the reverse side of the molded body 14 and the outer cover 13 to the lower side of the molded body 14 is effected.

Abstract: A double-nozzle deluge gun has a pair of nozzles arranged side by side rotatably on a rotatable table and an inter-nozzle control unit for adjusting the inter-nozzle angle measured between two lines obtained by projecting the radiation center lines of the nozzles onto a horizontal plane. Each nozzle has a deflector which is positioned in front of the nozzle during the very short range mode. Each deflector has a side cover which prevents water having passed through the deflector from excessively spreading sideways. The inter-nozzle angle and the water pressure are adjusted in accordance with desired water-reaching ranges, so as to achieve an optimal watering pattern in any range. Thus, the double-nozzle deluge gun can be controlled in accordance with desired water-reaching ranges, so as to achieve an optimal watering pattern having an appropriate width in any range.

Abstract: An anti-disaster system for receiving terminal data in response to the sequential calling of the terminals which is achieved by designating addresses from a receiver and for performing alarming or the like. Each of the terminals has an interrupt transmission section for transmitting a break signal which invalidates a terminal response signal on a timing when the terminal response signal to the receiver is transmitted when an abnormality is detected to notify generation of an interrupt.

Abstract: The present invention relates to an improvement of an ionizing smoke sensor having one radiation source and a two chambered structure consisting of an internal ionization chamber housing an internal electrode having a radiation source and defined by an intermediate electrode, and an external chamber where smoke can flow in, defined by an external electrode and irradiated from the radiation source through an opening in the intermediate electrode. Hitherto, in an ionizing smoke sensor having one radiation source and a two chambered structure, there has been a problem in that the giving of misinformation and noinformation occur when a little amount of thread, moisture or dust invades or a current of air flows an internal ionization chamber through an opening and an external ionization chamber. In addition, the electric field in the internal ionization chamber loses its homogeneity because of the opening, hence V-I characteristics preferable for the internal ionization chamber can not be obtained.

Abstract: By using the ratio of the G component to the R component G/R, or the ratio of the B component to the R component B/R, from a television monitor image, and referring to a conversion table for converting to distribution temperature, a surface temperature of a flame is found for each pixel. An area in which luminance signals included in an image of a surveillance area exceed a prescribed level is sampled as a flame outline, and at least the distribution temperature of a sampled flame region is detected, and distance to a radiant energy source is measured. The amount of radiant energy from the radiant energy source is estimated by computation, based on the sampled flame area and its distribution temperature and the distance to the source of radiant energy.

Abstract: A fire alarm system which radiates light towards a smoke detecting space. Scattered light resulting from smoke that may exist in the smoke detecting space is judged by a receiver with respect to the type of smoke that may prevail in the space. The presence of a fire is judged by comparing the light that has been received with a set threshold level. The threshold level is set to different levels in accordance with the type of smoke detected.

Abstract: 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.

Abstract: A pair of temperature detection devices having different heat time constants and an active device having a predetermined bias are connected in series. The bias is set so as to cause the active device to operate in a saturated region if the temperature is higher than a dangerous level, and to operate in a triode region if the temperature is lower than the dangerous level. The temperature detection devices are chosen so as to cause the voltage generated at the junction of the temperature detection devices to be higher than a predetermined reference voltage if the temperature has been raised to the dangerous level when the temperature is raised slowly, or if the temperature is raised rapidly, even if the temperature is lower than the dangerous level. A constant temperature function and a differential function are generated to detect that a fire has taken place.

Abstract: Disclosed is an anti-disaster system in which terminals are called by the polling system and in which the response signals from the terminals are received and decoded by a receiver to issue an alarming. Each of the terminals has an interrupt transmission section for transmitting an interrupt signal at a predetermined time during the receiver's transmission of the calling signal when an abnormality is detected. The receiver has an interrupt detection section for monitoring the predetermined time during the transmission of the calling signal to detect an interrupt signal from the terminal, and a calling control means for sequentially performing terminal group calling when the interrupt detection output is obtained from said interrupt signal detection section to specify the terminal in which abnormality data is detected.

Abstract: An ionization-type smoke sensor having a 2-chamber 1-radiation source structure including an inner electrode having a radiation source, an intermediate electrode having an opening through which radiation from the radiation source passes, an outer electrode through which smoke may flow inside from outside, and an insulator supporting and insulating the inner electrode, the intermediate electrode and the outer electrode. In the sensor, a fence portion made of an insulating material is formed on and projecting from a surface of the insulator which faces the outer electrode, the fence portion surrounding the periphery of the opening of the intermediate electrode. By virtue of this arrangement, even when the sensor is subjected to flow of air heading from outside toward the opening of the intermediate electrode, the fence serves to reduce the flow of air heading toward the opening, thereby enabling the characteristics of the sensor chambers to remain stable against flow of air.