Abstract: A fire alarm system which comprises one or more detecting sections for detecting a change in the surrounding phenomena due to a fire in an analog form; a storing section for storing the analog data output from the detecting section or sections; a level comparing section for comparing a data level represented by present instantaneous analog data output from the detecting section or sections and a predetermined level; fire judging instructing section which extracts a plurality of data stored during a predetermined period of time back to from the time when a comparison signal is obtained from the level comparing section, calculates a change amount between the respective extracted data and generates an output for initiating the calculation when the number of the calculated change amounts exceeding a predetermined amount exceeds a predetermined number; and a fire judging section for receiving the data stored in the storing section in response to the signal from the comparing section and/or fire judging instructing

Abstract: A flame detector comprising a flame sensor, a storing section for storing a predetermined reference value, a comparing section for comparing a value of a signal from the flame sensor which changes in amplitude corresponding to a change in flickering of flames with said reference value and adapted to detect flames when the value of said signal exceeds the reference value, and a flame determining section which comprises a computing section for computing a ratio of an amplitude value of a minus change component to an amplitude value of a plus change component of changes in flickering of flames. The storing section stores a preset first threshold value and a preset second threshold value higher than said first threshold value, and the flame determining section signifies the presence of flames is when the ratio of the amplitude values of the signals is larger than the first threshold value and lower than the second threshold value.

Abstract: An analog fire detector which comprises sensor means for detecting, in analog form, one or more kinds of quantity of state which change due to fire; a sampling means for sampling the detection outputs from the sensor means with a predetermined period; and fire determining means which predicts future fire data changes from the sampling data and generates a fire determination output signal when the prediction data satisfies predetermined fire conditions.

Abstract: A process for detecting a change in the physical phenomena caused by a fire in an analog form, periodically sampling the analog detection data, calculating moving average values of the time series sampling data for filtering, and establishing the sampling period and the number of smoothing data provided for the moving average calculation so that a cut-off frequency of the filtering is established which is coincident with the maximum frequency of the main frequency components of the analog detection data. The invention also relates to a fire detector and a fire alarm system for carrying out such a process.

Abstract: An apparatus is disclosed for releasably locking a fireproof door in an open position. A latch mechanism includes a hook connected to the door. The hook is releasably engaged with an actuator plate swingable between a latching position and a release position. Its motion is restricted by resilient means having bias adjustment means. A toggle mechanism keeps the actuator plate in its latching position until the toggle mechanism is struck by a remote-controlled solenoid plunger to release the door and let it close. If the solenoid malfunctions, the door can be closed manually with a force dependent on the setting of the bias adjustment means.

Abstract: 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.

Abstract: A light emitting unit and a photo sensing unit are separately arranged to face with each other, and a pulse light is emitted from the light emitting unit at every constant period, and the photo sensing unit receives the pulse light attenuated by a smoke, thereby detecting a fire. When a power source is turned on, a microcomputer in the photo sensing unit stores the first photo sensing data as an initial photo sensing data in a memory. The initial photo sensing data is fixedly stored and held and is not erased due to a temporary cut off of the power source. The photo sensing data is converted to correction photo sensing data using a correction ratio to perform the fouling correction and the fire is discriminated on the basis of the correction photo sensing data. The correction ratio is corrected when the correction period reaches 50 minutes. A correction amount of a single correction ratio is suppressed to a microvalue.

Abstract: 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.

Abstract: In an apparatus for closing a fireproof door, a holding device comprises a latch mechanism and a slider. The latch mechanism comprises an actuator member swingably supported in a housing which is provided with a tubular portion wherein a stopper is inserted and downwardly biased by a spring, the biasing force of the spring being adjustable by a screw which is threaded into the tubular portion. The slider is provided with an inclined surface at the front end thereof and a through-hole to receive the stopper therein. The slider is slid into the spacing formed between the actuator member and the housing with upwardly guiding the stopper by the inclined surface of the slider and the slider is locked by the stopper when it falls into the through-hole of the slider. The slider is released from the latch mechanism by swinging the actuator member or upwardly pushing the stopper against the biasing force of the spring.

Abstract: A smoke detector comprising a light emitting section from which pulse light is radiated to a detection area with a predetermined period and a light receiving section which is disposed so as to be opposite to the light emitting section to receive the light for detecting a change caused in the detection area in the form of a change in photo-output level. The light receiving section has a monitor terminal for outputting a monitor signal corresponding to the photo-output level. When a measuring apparatus is externally connected to the monitor terminal, the supervision period is shortened as compared with the normal supervision period, so as to enable the monitor signal to be supervised substantially in real time, thereby facilitating an adjusting operation.

Abstract: The detection signals regarding the temperature or smoke concentration generated due to the fire are sampled. The sampled data is processed by being averaged. An occurrence of a fire is determined on the basis of the processed data, i.e. - the averaged data, after completion of the averaging processes. The detection signals which are used for the fire determined are obtained by performing a moving mean calculation of a plurality of sampled data as one group and/or by executing a simple mean calculation of a plurality of moving mean data as one group.

Abstract: When a transmitter receives an abnormal detection signal from a leaked gas alarm or the like, the transmitter starts the transmitting operation and repeatedly transmits the detection information together with the address information by a radio wave for a constant transmitting operation time interval. A receiver is of the intermittent reception type whereby the receiving operation is performed at every constant idle time, thereby preventing a consumption of a power source of a battery. When the transmitting radio wave is received at a timing of the intermittent reception, the receiving operation is continued and an alarm signal is generated on the basis of the last information which is transmitted due to the single transmitting operation, thereby allowing an alarm representing the leakage of gas to be generated and closing a gas shut-off valve, or the like.

Abstract: A fire detector which outputs a change in physical phenomena caused by fire, such as a change in smoke density, in the form of analog voltage signal, by, for example, a photoelectric type sensor, an ionization type sensor, a thermal sensor, a gas sensor or the like, converts the output voltage into a pulse width corresponding to the voltage level by a voltage-pulse width converting circuit, counts quick clock pulses over the pulse width by a pulse counter, and transmits the count output from the pulse counter, in the form of digital signal, to a central signal station.

Abstract: An analog-type fire detector for detecting, in the form of an analog amount, a change in physical phenomena caused by occurrence of a fire, which intermittently detects a change in the ambient physical phenomena caused by occurrence of a fire, generates an analog signal corresponding to an amount of the change, converts the analog signal into a pulse signal of a duration corresponding to the level of the signal, generates periodically from a reference pulse generating means a reference pulse of a predetermined duration, detects by a discriminating means a difference in pulse durations between the output signal from the pulse duration converting means and the reference pulse, charges or discharges a capacitor corresponding to the difference detected, and hold-outputs for a predetermined period by a hold-outputs means a signal corresponding to a voltage across the capacitor at the time when the charging or discharging is stopped.

Abstract: In an apparatus for closing a fireproof door in case of emergency, the fireproof door and a release, which is secured to a door frame, are interconnected by a link mechanism comprising first, second and supplemental link arms. One end of the first link arms is pivoted to a driving shaft of a door closer secured to the fireproof door. The other end of the first link arm is pivoted to one end of the second link arm, the other end of which is pivoted to the release. The supplemental link arm is connected between the central point of the second link arm and a slider which is slidably mounted inside the release and latched by a latch mechanism when the fireproof door is open.When the slider is released from the latch mechanism by electrizing a solenoid which operates the latch mechanism, the slider is slid inside the release by the closing force of the door closer transmitted via the link mechanism, thereby closing the fireproof door.

Abstract: In a fire detection system having at least one fire sensor, a receiver including a power source connected to the fire sensor for supplying a power source voltage to the fire sensor and a receiving relay for receiving a fire detection signal from the fire sensor, and at least one power/signal line for coupling the fire sensor to the receiver, the receiver comprises a timer for producing a clock signal over the time of day and command means for providing predetermined detection sensitivity change commands of the fire sensor which are programmed according to the time of day in response to the clock signal from the timer, and the fire sensor comprises sensitivity change control means for changing the detection sensitivity of the fire sensor in response to the detection sensitivity change command from the command means. The fire detection sensitivity of the fire sensor is varied in accordance with predictive fire damage conditions predetermined in view of the activities of people during the time of day.

Abstract: In a communication system including communication transmitting means for modulating a carrier wave having a fixed frequency by a communication signal having communication content and for radiating the modulated signal wave, and receiving means for receiving the modulated signal radiated from the communication transmitting means to demodulate the communication signal, the communication system comprises a communication shielding area provided at a desired location on a boundary between communication areas for limiting the extent of the communication areas in which the modulated signal is transmitted, and shielding transmitting means for transmitting the shielding signal wave into said communication shielding area, the shielding signal wave being received by the receiving means tuned to the carrier wave frequency at a signal receiving level equal to or more than the receiving level of the modulated signal.

Abstract: In a photoelectric detector having a light transmitting section and a light receiving section disposed remote from each other, intermittent illumination of a light source of the light transmitting section is detected and processed by the light receiving section in synchronism with the intermittent illumination by way of power lines interconnecting the light transmitting and light receiving sections. To this end, a circuit for intermittently supplying a power source to the light transmitting section is provided in the light transmitting section or the light receiving section and the intermittent power supply is utilized as a synchronizing signal to intermittently illuminate the light source and to allow the light receiving section to transmit and process a received light signal or a signal based thereon in synchronism with the intermittent illumination.

Abstract: 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.

Abstract: Fire detection signals are produced with high reliability based upon a quantity smaller than a predetermined quantity from a fire sensing system which detects predetermined standard quantities of combustion products (or physical quantities) such as heat, smoke or light produced by a fire. The system includes a fire sensor connected in parallel with a first semiconductor switching element and a second semiconductor switching element contained in two independent power-supply circuits. The first power-supply circuit contains the first semiconductor switching element which detects a combustion quantity smaller than the standard quantities and which is rendered conductive upon receipt of an early output produced by the fire sensor. The first power supply circuit is connected in parallel with a second power-supply circuit containing the second semi-conductor switching element which detects the standard quantities and which is rendered conductive upon receipt of an alarm output produced by the fire sensor.