Abstract: A smoke density monitor system comprises an imaginarily dividing a space to be monitored two-dimensionally into a plurality of imaginary subspaces so that plural paths passing through a plurality of arbitrary subspaces are arranged to intersect each other; measuring the transmittance of light along each path; calculating a transmittance of light at each imaginary subspace using a mathematical method in which the measured result of the transmittance of the each path are placed into matrices and the solution to an equation involving the matrices is carried out with matrices; and determining a smoke density at each of the imaginary subspace on the basis of the transmittance at each subspaces.

Abstract: In a fire monitoring system for monitoring the occurrence of a fire in which a space to be monitored is imaginarily subdivided into plural subspaces so that plural channels passing through the subspaces are set so as to intersect to each other in a lattice form. The propagation speed of ultrasonic waves propagating through each of the channels is measured, on the basis of which the propagation speed of the ultrasonic waves in each of the subspaces is calculated in the same manner as the solution for each element of a matrix is obtained, and then the temperature in each of the subspaces is obtained. By providing the system with a humidity sensor, the temperature for a dry condition is obtained.

Abstract: An alarm apparatus includes a plurality of sensors connected in parallel with each other between sensor lines extending from a receiver and sounding devices connected between the sensor lines in correspondence to at least one of the sensors. The receiver includes a unit for changing a voltage supply condition of the sensor lines. A control circuit is provided to each audio device so as to selectively control the audio devices when the voltage supply condition is changed, so that a audio device corresponding to an activated sensor, or all of the audio devices, can be arbitrarily controlled to generate audio alarm signals.

Abstract: A fire sensor of the polling type in which plural fire sensors connected via a common line to a central monitoring point are called in sequence in accordance with individual addresses, wherein an address setting section in the fire sensors is improved. Address setting rotary digital code switches are installed on a printed circuit board on which the other components of the sensor are mounted, and holes for accessing the rotary code switches are formed in a body case in positions confronting the switches.

Abstract: An environmental abnormality detection apparatus has a detection portion for detecting a phenomenon such as a fire or gas leakage, and a signal processor such as a microcomputer or the like for determining whether an environmental abnormality has occurred in accordance with a detection signal from the detection portion and for generating an alarm signal when the abnormality occurs. A power source control circuit is provided to intermittently supply power to the signal processor and to stop power supply in accordance with an end of processing signal from the signal processor.

Abstract: A centralized monitoring method for fire alarm processing, wherein, with respect only to specially designated ones of plural terminal units at least special data common to the special terminal units is transmitted to a central unit with priority over all other data and irrespective of a predesignated calling sequence. The central unit then responds to the special terminal units with absolute priority.

Abstract: A composite detector includes a plurality of sensors of the same or different types, a plurality of analog switches connected to outputs of the plurality of sensors, and an operation circuit, such as an operational amplifier. The sensors detect physical phenomena such as heat, smoke and gas according to different principles of detection, and output analog detection signals. The analog switches are controlled by a selector operated with a control signal from a central monitor or magnitudes of outputs from the plurality of sensors. The operation circuit calculates outputs from the plurality of analog switches.

Abstract: A fire sensing unit is provided with apparatus which sends out a code identifying the type of sensor apart from transmission of the quantized signals of the analog output of the sensor of the sensing unit. Thus the data processing unit of the receiving unit of a fire detection system including the sensor can be simplified because the receiving unit need not collate the types of the installed sensors with a list of addresses stored therein. Also replacement of sensors can be easily effected since the information regarding the type of sensors is stored in the sensing unit.

Abstract: A separation type detector includes at least one pair of transmission and reception units connected through a transmission line, detects environmental abnormality according to changes in pulse beams or ultrasonic waves transmitted from the transmission unit and received by the reception unit, and sends an abnormal signal to a central monitor through the transmission line. The transmission and reception units respectively include transmission circuits assigned with an identical address. The pair of transmission and reception units are synchronously operated in response to a command from a central monitor.

Abstract: In a light-transmission type smoke detector, a smoke chamber is composed of a disc-like block of a non-conductive material one side of which has a spiral groove and is coated with a conductive bright metal film and a casing mounted on the block, said casing having a plurality of labyrinth structure smoke entrances. An electric circuit system is placed on the other side of the disc-like block and is covered by a shield sheet. The shield sheet and the coating metal film are electrically connected to shield the electric circuit system.

Abstract: A fire alarm system employing multiple sensors can accurately and quickly respond to real fires with an alarm signal and prevent issuance of a false alarm due to noise or the like. A pair of decision circuits in a fire signal receiver receive fire detection signals from respective sensors and produce fire occurrence signals representing a first level of probability that a fire has occurred and decision signals representing a second lower level of probability that a fire has occurred. A fire alarm is issued when a fire occurrence signal has been outputted by any one of the decision circuits or when a decision signal is simultaneously outputted by both decision circuits.

Abstract: An improved apparatus for detecting environmental disturbances such as the occurrence of a fire, a gas leak or the like, includes a central processing unit and a plurality of terminal detectors, wherein an identification code is assigned to each of the detectors and the central processing unit sequentially calls the detectors in rotation requesting them to transmit thereto the data collected on smoke concentration, gas concentration, temperature or the like. The apparatus is provided with a display unit and a memory. Data collected by each detector concerning on the environmental condition of the place where each detector is installed are stored in the memory in time series. When a signal for data exceeding a fixed reference level is received, a provisional alarm is raised for the operator and the stored data for a limited period of time in the past are displayed.

Abstract: A signal transmitting junction unit for a hazard alarm system includes a signal transmission control unit, a zone line circuit connected to an electric source and having at least one hazard sensor connected thereto and an analog digital convertor; and the zone line circuit outputs the source voltage when a sensor connected to the zone line detects a hazard, outputs a voltage between the source voltage and the zero voltage when the sensor is under the normal monitoring standby condition, and outputs no voltage when the sensor is out of order upon calling from the central control unit and the voltage is digitized by the analog-digital converter and sent back to the central control unit through the transmission control unit.

Abstract: In a polling type surveillance control apparatus for a security system, inherent addresses are assigned to respective terminal devices such as smoke detectors, temperature sensors, gas leakage detectors, fire partitions and smoke dampers. When a self address detector in the terminal device detects a coincidence between the address signal from a central station and a preset self address, the terminal device indicates it has been accessed or energized and power control thereof may also be performed.

Abstract: In the light-scattering type smoke detector with a disorder detecting circuit, the Munsell value of lightness of the inside surface of the dark chamber is raised to 2-4. Thereby, not only disorder of the apparatus but also performance drop of apparatus parts can be detected.

Abstract: A photoelectric smoke sensor terminal has an address signal detector for detecting whether or not an address assigned to the terminal coincides with an address represented by an address signal from a main unit. Only when the coincidence signal is supplied to a switch circuit is a photoelectric smoke sensor turned on. The terminal also has an item data memory for supplying item data (e.g. gas leakage and smoke generation data) so that a plurality of item data signals together with an output signal from the sensor can be transmitted on a single transmission line.

Abstract: An atmospheric abnormality detection system includes a command discriminator and a display/alarm circuit in each sensor terminal. When the command discriminator receives a coincidence signal from an address comparator, the command discriminator causes an A/D converter to convert an analog sensor output to a digital signal as response data. When an abnormal state display command is transmitted from a main unit to the command discriminator, the command discriminator causes the display/alarm circuit to display information indicating the abnormal state and/or generate an audible alarm.

Abstract: An alarm terminal device has a lower limit voltage generator for generating as a lower limit voltage an analog signal which is produced from a temperature sensor and which is lower than a first predetermined value, and an upper limit voltage generator for generating as an upper limit voltage an analog signal which is produced from the temperature sensor and which is higher than a second predetermined value. At least one additional sensor is provided for generating an analog data signal having a voltage higher than the upper limit voltage or lower than the lower limit voltage so as to indicate any information other than that contained in the analog signal from the temperature sensor. A disconnection or a short circuit of a platinum resistor of the temperature sensor can thus be represented by the analog data signal to be quantized by an analog-to-digital converter employed in the sensor.