Abstract: In a method for frequency analysis of a signal of a hazard detector, wavelet transformation is combined with fuzzy logic analysis. In the transformation, based on orthonormal or semi-orthonormal wavelets, an original signal is fed to a multi-stage filter cascade of pairs of high-pass/low-pass filters. From the output of the high-pass filter, wavelet coefficients and values of the original signal, each filter stage produces an association function. The functions are normalized and analyzed further in accordance with fuzzy logic rules. The method is particularly suitable for analyzing signals from flame detectors, noise detectors and the like. As processor code for transformation and analysis is kept short, high speed and accuracy are achieved at low cost.

Abstract: A flash and voice warning system generally comprises a power supply with charging circuit, a smoke sensor power supply and auto reset circuit, a smoke sensor (or manual operation), a circuit for converting current to voltage, a single-chip microprocessor, a 60 Hz square wave generator, a control circuit, a buffer, a current amplifier, a high-voltage circuit, N-discharge tube circuits, N-triggering circuits, a flash lamp direction control circuit, and a voice circuit. The smoke sensor is arranged in an appropriate position of a building and the other circuits are mounted within a control box made of fire-proof material. Hence, the flash and voice warning system for fire accidents can direct people where to flee from the fire in case of fire accidents.

Abstract: A method and system for preventing smoke and fire damage in a clean room within which a tool including an electrically powered element is located. The method includes the step of providing the tool with a system including a fire proof housing, a sensor, an environmental sealing mechanism, an operator panel and a controller. The fire proof housing is secured over the tool and includes a door and at least one port to the tool. The sensor monitors an environmental condition within the housing and generates a sensor signal. The environmental sealing mechanism seals the at least one port and the door to the housing in response to the control signals to render the housing environmentally sealed. The operator panel includes visual indicators responsive to actuation signals. The controller is adapted to receive and process the sensor signals and to execute a shutdown control sequence during which the control signals and the actuation signals are generated.

Abstract: A controlling interface unit is linked to a plurality of event sensors associated with a premises. There is at least one manner of establishing communication, using wired communication lines or radio transmissions between this interface unit and, on the one hand, a remote alarm receiving center for monitoring the sensors at the premises, and, on the other hand, a remote auxiliary facility for filtering out potential false alarms from those premises. The interface unit is capable of routing signals originating from a selected type of sensor to the auxiliary filtering facility instead of or in addition to transmitting the same signals to the alarm receiving center. Depending on the circumstances, feedback signals may then be transmitted from the auxiliary filtering facility to the controlling interface unit to negate an alarm condition. Optionally, a memory unit may be linked to the controlling interface unit to store data from the event sensors for a limited time period.

Abstract: An ambient condition detector includes a sensor for a first ambient condition and a second, sensor which is responsive to a second ambient condition not necessarily correlated to the first condition. Control circuitry, coupled to both sensors, processes an output from the first sensor to reduce transients and/or noise therein which are not correlated to the first ambient condition. Processing characteristics are altered in response to an output from the second sensor. The processing can take place at the detector or, in part, at the detector and, in part, at a displaced, common control element.

Abstract: A fire alarm radio transmitter and receiver set is provided with a radio transmitter and a radio receiver. The radio transmitter has a plurality of temperature sensors, a first memory keeping data including an address of a building, a first controller for generating transmission data by combining the data and an identification code and for allowing an alarm to emit an alarm signal, a frequency generator for generating a frequency radio signal and for mixing the frequency radio signal with the transmission data and a transmitter for transmitting the transmission data.

Abstract: An electrical fire sensing and fire prevention/extinguishing system which senses properties of electrical fires in cabinets having electrical circuits or circuit boards and detects sparks for detecting an electrical short in the electrical circuits or circuit boards. Upon detecting a spark, power to the electrical circuits or circuit boards is turned off to prevent a fire from developing within the cabinet. Furthermore, the electrical fire sensing and fire prevention/extinguishing system senses heat increases and smoke for activating a fire extinguishing device to extinguish a fire and turning off power to the electrical circuits or circuit boards.

Abstract: A controller which controls the operation of the solenoid valve that regulates the flow of gas to the burner within a fuel-gas fired burner system is disclosed. The controller performs a number of diagnostic tests on the system components and provides an output in the form of a series of pulses having a specific code"embedded" therein to identify a fault condition when it occurs. The series of pulses is applied to a light emitting diode. A code reading device having an optical sensor and a liquid crystal display is provided to intercept the light pulses emitted by the light emitting diode and to"translate" the code embedded therein so that the specific fault condition can be identified and displayed on the liquid crystal display.

Abstract: The asset monitoring system and associated method includes an asset monitor for providing a remotely located central station with information relating to a container, such as a trailer, both during tethered periods in which the energy storage reservoir of the asset monitor is electrically connected to an external power source, such as the electrical system of a tractor or truck, and during untethered periods in which the energy storage reservoir of the asset monitor is electrically untethered or disconnected from the external power source. As a result, the energy storage reservoir is recharged by energy received from the external power source during tethered periods and supplies energy to the asset monitor during both tethered and untethered periods. The asset monitor also includes a controller for controlling its operations. The controller includes tether status determining means for separately identifying tethered periods and untethered periods.

Abstract: A method of detecting the content of impurity in a gaseous medium has the steps of continually detecting impurities in the gaseous medium, emitting analyzing signals that vary with variation in impurity content, and statistically analyzing the emitted signals. When statistically analyzing the emitted signals, newer signals are accorded greater influence on outputs than are older signals, which become gradually less influential.

Abstract: An alarm apparatus for shaking a piece of furniture in response to detection of a physical occurrence, such as smoke, fire, CO.sub.2, or even a burglar, is provided. The apparatus includes a detector for detecting the physical occurrence and emitting a signal in response thereto. Connected to the detector is a signalling device that is positioned adjacent the piece of furniture to be shaken in response to the signal emitted from the detector. The signalling device includes a rotating cam shaft with a cam member thereon, against which is positioned one end of a cam follower. The opposite end of the cam follower is directed toward the piece of furniture, so that movement of the follower over the cam as the cam shaft rotates causes the furniture to move up and down.

Abstract: A monitoring apparatus for alerting an operator to the need to change a temperature control system filter includes a mechanism for selecting and setting a primary period of filter use to assure replacement before the filter becomes clogged; a mechanism for counting out the selected primary period; a mechanism for activating a signalling device to signal the operator to replace the filter, absent replacement of the filter; a mechanism for sensing replacement of the filter; a mechanism for resetting the mechanism for counting to begin the counting out the selected primary period again upon replacement of the filter; a mechanism for counting out a secondary period measured from the end of the primary period; a mechanism for shutting down the system at the end of the secondary period absent replacement of the filter; and a mechanism for detecting a fire within the building. The apparatus preferably additionally includes a mechanism for shutting down the temperature control system upon detection of a fire.

Abstract: An intelligent fire detection system is disclosed which includes a control panel and a plurality of detectors distributed throughout the building being protected. The software of the panel treats the detectors as being in one or more groups. All the detectors in a group can be in the same room. The detectors are set so as to be sensitive to small concentrations of smoke eg 0.3% per meter obscuration. Only if all the detectors in a group, or a predetermined lesser number of the detectors in a group, have smoke concentrations at or above the threshold level does the panel establish an alarm condition. The panel can also establish an alarm condition when the presence in any single detector of smoke at a higher concentration eg 3% per meter obscuration is detected. The system can alternatively include detectors sensitive to other emissions from a fire eg heat, ionized particles or carbon monoxide.

Abstract: A new door with built-in smoke and fire detector for incorporating a smoke and fire detector into a door. The inventive device includes a door having a generally rectangular configuration. The door includes front and rear surfaces. The door includes a short upper edge, a short lower edge, and long opposed side edges. The short upper edge has a recess extending inwardly thereof. The front and rear surfaces have a plurality of openings therethrough in communication with the recess. An alarm system is coupled with respect to the recess in the short upper edge of the housing.

Abstract: A smoke detector that comprises three different power sources. First one is the 110/220 volt AC house current, through a step down transformer or that can be hard wired into the home or factory. Second one is a moveable 9 volts rechargeable backup battery. Third one is a solar cell array with a plastic lens that provides up to 9 volts of current through a trickle charger/voltage regulator. The trickle charger also used to recharge the backup battery. With the trickle charger, the solar cell array can cause the smoke detector to alarm with only enough ambient light. The instant invention of the smoke detector unit overcomes the limits of the now market available smoke detectors, by being adjustable, moveable providing more current via the solar cell array to provide a complete recharge to the backup battery. Any voltage lower than 9 volts will lower the charge of the 9 volt rechargeable battery to the current 8 volts to 8 volts and so on up to 9 volts.

Abstract: A fire detector, for connection in a fire protection/alarm system, comprises an array of sensors, or a single sensor, of the semiconductor resistor type impregnated with a noble metal. The detector is responsive, by way of a decrease in its resistance, to an increase in any one or more parameters indicative of a fire, namely the atmospheric concentrations of carbon monoxide, hydrogen and water vapor, and temperature, so that a fire is detected regardless of which of these indicators is present. The sensor responds to all of the parameters, and the output signal simultaneously represents changes in all the parameters.

Abstract: The present invention utilizes the modulation ratio between the flicker of a sensor signal and the absolute signal average to detect fire conditions. The system of the present invention requires that the signal on a sensor channel be above a certain threshold and the ratio of the flickering portion of the signal to the absolute signal average be within a certain range. The system may be applied to any sensor signal in response to any source, including, but not limited to, radiation, acoustic or optical signals including ultraviolet, visible or infrared radiation. Signals may be filtered with a median filter to remove noise. A least-mean-square curve-fit is made to the data to account for any growth or decay in the fire signal. The flicker can be calculated using any of several metrics such as standard deviation, p-norms, or maximum deviation, but mean deviation seems to provide optimal performance. The modulation ratio system can be augmented with a separate detection scheme for large-scale fires.

Abstract: A system and method for automatically detecting fires in select areas, and reacting thereto to put out the fires. A stationary, earth orbit satellite, pilotless drone aircrafts or piloted aircraft contains one or more infrared detectors and optical means for detecting small fires when they first occur in fields and wooded areas, preferably where man made campfires and trash dumping are prohibited. A computer in the satellite, drone or piloted aircraft and/or on the ground receives and analyzes image signals of the earth area or areas being monitored and, upon detecting infrared radiation of varying intensity and variable shape, indicative that a fire has started, generates coded signals which are (a) indicative of the coordinate locations of the fire, (b) the extent of the fire, (c) the shape of the area(s) burning, (d) the direction of movement of the fires (e) the speed(s) of the flame fronts, (f) smoke condition, (g) intensity of the fire, (h) fire ball location(s), etc.

Abstract: A fire detector having a greatly reduced frequency of generating false alarms. An AND gate is responsive to outputs from first and second fire detector modules that are responsive to the detection of first and second characteristics of a fire, respectively, to signal the detection of a fire if both of these characteristics have been detected. At least one override path is included to enable the occurrence of a particular type of fire to be signaled that would not otherwise be signaled by the output of said AND gate.

Abstract: A method and system for determining flame characteristics in the time domain by analyzing the fluctuations of a time-domain output signal of a flame scanner monitoring a burner flame. A mean level (as well as maximum high and low levels) of the time-domain signal are determined during a predetermined time interval. Numerous intermediate levels are positioned between the mean level and the high and low levels. Several crossing numbers are obtained by counting how often the signal crosses the mean level and the intermediate levels during the time interval. These crossing numbers are plotted on a graph, wherein the crossing numbers are plotted against the relative distance between the levels. A curve is interpolated between the points thus obtained and an area under the curve is determined. The crossing numbers are normalized to the area to obtain normalized crossing numbers.

Abstract: A home safety system comprising a smoke detector, a carbon monoxide detector and a microphone connected to a transmitter. The smoke detector is powerable by a/c current and by a battery, and comprises a sensor for sensing smoke connected to an audible alarm signal. The carbon monoxide detector is powerable by a/c current and by a battery and comprises a sensor for sensing the presence of carbon monoxide connected to an audible alarm signal. The transmitter comprises means for communicating signals from the carbon monoxide detector and smoke detector to a remote location. The invention further comprises an emergency lighting system connected to the carbon monoxide detector and smoke detector. The light system is powered by a battery and adapted to turn on in the event of a power failure, a signal from the smoke detector or a signal from the carbon monoxide detector. The lighting system can also be used as a night light.

Abstract: An electronic alarm system of the kind used in commodity surveillance systems includes an alarm element which is adapted to receive a magnetic alternating field transmitted from a transmitter by means of a transmitter coil and also adapted to re-transmit a magnetic alternating field, wherein a receiver which includes a receiver coil is adapted to receive and detect the re-transmitted alternating field. The transmitter coil and the receiver coil are one and the same coil (1). Between the transmitter (TX) and the receiver (RX) on the one side and the transmitter-receiver coil (1) on the other side, there is provided an electronic unit (14) which includes a transformer (5) and a resistance (2) which are so adapted that when transmitting, a first part of the transmitter power will be applied to the transmitter coil (1) and the remaining part, a second part, will be applied to the resistance (2).

Abstract: A multifunction passive infrared occupancy sensor functions as an occupancy sensor for security systems and also as an occupancy sensor for energy management control systems. The occupancy sensor comprises at least one segmented infrared lens array wherein the segments of the infrared lens array establish different optical lobes in the field of view of the occupancy sensor. At least one pyroelectric infrared detector is positioned at or near the focal point of the segmented infrared lens array, for detecting movement of infrared sources within the field of view of the occupancy sensor and producing an output signal representative thereof. A processing means analyzes the output signal of the detector for security detection purposes by detecting changes in the output signal greater than a given security threshold.

Abstract: A forest surveillance and monitoring system for the early detection and reporting of forest fires in a forest area under surveillance. The system comprises a number of remote detectors placed within the forest area and telemetrically linked to a central processing system. Each remote detector comprises an infrared sensor and video camera mounted on a remotely controllable moving platform. The remote detector also contains a weather sensor for collecting critical weather data at the remote site. Located at each remote site is a remote processor which controls all data collection, the remote processor being in communication with the central site via a remote communication subsystem and central communication system which are linked via radio. The central control site receives weather data and alarm information as well as video images from the remote detector site via the communication system.

Abstract: A system for imaging a flame and the background scene. The flame imaging system consists of two charge-coupled-device (CCD) cameras. One camera uses a 800 nm long pass filter which during overcast conditions blocks sufficient background light so the hydrogen flame is brighter than the background light, and the second CCD camera uses a 1100 nm long pass filter, which blocks the solar background in full sunshine conditions such that the hydrogen flame is brighter than the solar background. Two electronic viewfinders convert the signal from the cameras into a visible image. The operator can select the appropriate filtered camera to use depending on the current light conditions. In addition, a narrow band pass filtered InGaAs sensor at 1360 nm triggers an audible alarm and a flashing LED if the sensor detects a flame, providing additional flame detection so the operator does not overlook a small flame.

Abstract: Outputs from a smoke detector and non-fire sensors such as temperature and humidity can be combined to produce a delay in a signal from the smoke sensor indicative of a potential fire condition. The signals can be combined locally and all of the sensors can be carried in a single housing. Alternately, the sensors can be carried in separate housings and combined at a remote control panel. The value output from the humidity and temperature sensor can be used in determining whether or not to produce a delay. Alternately, the rate of change of either or both parameters can be used to determine whether a delay is necessary.

Abstract: A fire sensor according to the present invention includes a sensor base, a sensor body and an address unit. The sensor base is mounted and fixed on a predetermined position, for example, a ceiling. The sensor body includes a plurality of pins for electrically connecting the sensor body with the sensor base, and a first fitting member for electrically and mechanically connecting the sensor body with the sensor base. The plurality of pins are formed on a surface of the sensor body connectable to the sensor base and circumferentially arranged on a circle with a predetermined radius. The sensor base has a second fitting member which is electrically and mechanically fitted to the first fitting member.

Abstract: An ionization chamber for use in a smoke detector includes first and second outer electrodes and a non-reflective center electrode. The non-reflective center electrode can be formed as a metal electrode having a non-reflective coating or as a non-reflective, conductive plastic elements. The ionization chamber can be incorporated into combination smoke detector which includes a photoelectric sensor. A non-reflective center electrode, associated with the ion-type sensor is symmetrically located in the detector and displaced from the photoelectric sensor.

Abstract: A flame detector employs a plurality of wavelength selective radiation detectors and a digital signal processor programmed to analyze each of the detector signals, and determine whether radiation is received directly from a small flame source that warrants generation of an alarm. The processor's algorithm employs a normalized cross-correlation analysis of the detector signals to discriminate between radiation received directly from a flame and radiation received from a reflection of a flame to insure that reflections will not trigger an alarm. In addition, the algorithm employs a Fast Fourier Transform (FFT) frequency spectrum analysis of one of the detector signals to discriminate between flames of different sizes. In a specific application, the detector incorporates two infrared (IR) detectors and one ultraviolet (UV) detector for discriminating between a directly sensed small hydrogen flame, and reflections from a large hydrogen flame.

Abstract: A flame is detected by signal analysis for intensity variations in radiation received by a sensor. A low-frequency spectrum of the signal is analyzed for mid- and cut-off frequencies, and the signal is classified as periodic or non-periodic. Periodic signals with a mid-frequency (.omega..sub.mp) above a first frequency value (G.sub.1), and non-periodic signals with a cut-off frequency (.omega..sub.gc) above a second frequency value (G.sub.2) are classified as interfering signals. The first frequency value is determined by the flicker frequency of a stationary flame having a magnitude corresponding to a flame of minimum magnitude to be detected. The second frequency value is selected greater than the first frequency value (G.sub.1).

Abstract: A fire detector having a greatly reduced frequency of generating false alarms. An AND gate is responsive to outputs from first and second fire detector modules that are responsive to the detection of first and second characteristics of a fire, respectively, to signal the detection of a fire if both of these characteristics have been detected. At least one override path is included to enable the occurrence of a particular type of fire to be signalled that would not otherwise be signalled by the output of said AND gate.

Abstract: An alarm for sensing different conditions of an ambient air presents a housing for an alarm circuit, the housing having lobes for first, second and third circuit sensors surrounding a single circuit alarm. The alarm circuit delivers the current to a logic chip which produces a current for sounding the alarm in different patterns according to the sensed air condition. The configuration of the housing depends the alarm below the housing proper so as not to interfere with the alarm sound. The housing allows the installation of three air condition sensors at one selected location.

Abstract: A fire alarm system utilizes outputs from different types of fire sensors, such as photoelectric smoke sensors or ionization type smoke sensors and combines those outputs by subtraction so as to establish a delay interval during which one or both of the sensor output values must exceed a predetermined threshold value to cause the system to go into an alarm condition. Prior to subtracting the outputs from one another, each of the outputs can be raised to a predetermined exponential value so as to emphasize the effects of larger sensor output values. Where the two types of fire sensors each are generating outputs indicative of a fire condition, the calculated delays will be relatively short. In instances where only one of the two sensors is generating an output indicative of a fire condition, the calculated delay will be longer, so as to inhibit false alarms.

Abstract: The application describes a method and apparatus for detecting fire. The apparatus includes a fire detector and a mounting means adapted for attachment to both existing structures and new construction in such a manner as to not protrude into the interior spaces of structures. The method includes the steps of providing a fire detector and recessing the detector into the walls of the structure providing power to the detector and monitoring the detector.

Abstract: A camera includes a plurality of photosensors disposed on an imaging surface. The photosensors separately output respective photodetection signals, and are grouped into a plurality of photosensitive units each including at least two of the photosensors. The photosensors of each of the photosensitive units have respective detection wavelength ranges which do not overlap one another. The photodetection signals outputted from selected ones of the photosensors of each of the photosensitive units are used in performing spectrum analysis. R (red), G (green), and B (blue) signals are synthesized from the photodetection signals outputted from the photosensors of each of the photosensitive units and are used in displaying an ordinary color image.

Abstract: An electric control is shown for gas furnaces which controls fan motors and ignition controls based on inputs from a room thermostat (32), a high limit control and an ignition control (14) including a gas valve. A flame sense circuit (42, 42') is coupled to a microprocessor (U2) and includes a flameprobe (P1) energized by line power through a capacitor (C3) via a quick connect (QC31). A capacitor (C4) is charged by a 5 volt DC source through resistor (R12) and inputted to an inverter (U3, S2) which provides a low signal to the microprocessor when no flame is present. When a flame is present the capacitor (C4) discharges through the flame causing the inverter to change state providing a high to the microprocessor indicating that a flame is present. A diagnostic network comprising a low leakage diode (CR10) and serially connected resistor (R11) is coupled between the microprocessor (pin 8) and the input of the inverter (U3) so that the operation of the flame sense circuit can be tested.

Abstract: A test circuit for testing a signal input circuit having a threshold, an operational amplifier 3, for example, which converts voltages of input signal into a binary signal and supplies it to a logic circuit, a register 8, for example, is provided with signal lines 91, 92 connecting an input end and an output end of the register 8 through a switch 9. The test circuit judges a threshold of the operational amplifier 3 on the basis of voltage of a signal inputted to the operational amplifier 3 and a value of an output signal outputted from the operational amplifier 3 through the signal line 91, the switch 9, and the signal line 92 by turning switch 9 on. It is possible to perform testing at high speed without software processing. It is also possible to make the occupied area on one chip small when a plurality of signal input circuits are provided on the chip.

Abstract: A system for detecting randomly occurring signals, particularly signals representative of a fire condition, having a radiation detector for receiving the signals, peak detector circuits for identifying the peak values of the received signals, peak duration signals for determining the time between adjacent peak signals, and a collection buffer for accumulating values representative of successive peak durations. The peak duration times are compared and evaluated to determine whether regularly occurring patterns of the received signals exist, or whether the received signals are randomly occurring, and an output signal is generated whenever the comparison indicates that the received signals are random in nature.

Abstract: A fire detector includes a scattered light detector unit and an ionization detector unit which are arranged upon a common base at each side of the center axis of a compartment defined by the base and a peripheral wall extending from the base. The scattered light detector includes a light source and a receiver, with their principal axes intersecting in a point of intersection which is positioned at one side of the center axis of the compartment and thus extends eccentric to the center axis. The ionization detector unit includes a holder for a preparation to be ionized, with the holder being arranged at the other side of the center axis. Suitably, a heat detector is further provided in the center axis.

Abstract: A fire alarm which consists of a housing, an alarm assembly and a switch assembly. A driving spring in the alarm assembly is used for storing driving energy. As soon as a nylon string in the alarm is burnt and broken, the driving spring will drive small hammers to hit a bell cup to send out a warning signal to warn people that a fire is taking place. At the same time, a switch is closed to actuate an electric alarm to provide a persistent alarm as long as electric power is available.

Abstract: A fire detection apparatus discriminates white smoke, black smoke and flame in a protected area based on changing characteristics of optically measured distances. The apparatus includes a distance meter having a light emitter for emitting a pulse of light energy towards a reference object, such as a distant wall, and a light detector for receiving the pulse of light energy reflected from the reference object or any intervening object. A distance to the reference object or the intervening object is determined based on the lapse of time from the emission to the detection of the pulse of light energy. White smoke is deemed detected when the distance measured is less than a reference difference and is substantially free of fluctuations. Black smoke is detected when the distance measured is more than the reference distance and is also substantially free of fluctuations. Flame is detected when the distances measured differ from the reference distance and fluctuates substantially.

Abstract: Disclosed is a fire detection and engine monitoring system of the type which utilizes a pair of elongated thermistor strands extending over substantially the same path to provide redundancy. A resistance of the two thermistor strands are sensed and a resistance difference signal is generated. The resistance signal is monitored for abnormal differences between the two identical thermistor devices which are essentially exposed to the same operation conditions. Such differences are indicative of the deterioration over time of the condition of one of the sensors.

Abstract: An apparatus and method is disclosed for a fiber optic based fire detection and tracking system. An optical time domain reflectometer (OTDR) interrogates at least one optical fiber with a melting point defining a threshold temperature for fire detection. The OTDR measure the time of flight of a light pulse originating at each optical fiber input end and reflected back to determine the linear position of interruptions along an optical fiber which allows for fire detection and location.

Abstract: An improved method of locating an underground mine fire by comparing the pattern of measured combustion product arrival times at detector locations with a real time computer-generated array of simulated patterns. A number of electronic fire detection devices are linked thru telemetry to a control station on the surface. The mine's ventilation is modeled on a digital computer using network analysis software. The time reguired to locate a fire consists of the time required to model the mines' ventilation, generate the arrival time array, scan the array, and to match measured arrival time patterns to the simulated patterns.

Abstract: A system for detecting fires uses at least two carbon dioxide sensors positioned at spaced locations in a room. Each sensor produces an electrical output signal representative of the carbon dioxide concentration in its vicinity. A computer calculates the ratio of the concentration sensed by each sensor to the concentration sensed by each of the other sensors, and any imbalance in the distribution of carbon dioxide will be reflected in these ratios. Random variations prevent the ratios from being equal, and the magnitude of the random variations is quantized by calculating the standard deviation of the ratios. The ratios are then normalized and compared to a threshold level that corresponds to a chosen false alarm rate.

Abstract: There is disclosed a multi-zone microprocessor fire control apparatus. The control apparatus employs a microprocessor which monitors a plurality of zones. Each zone may be associated with a smoke detector and which smoke detector will provide a predetermined condition when smoke is present in a zone. The microprocessor is controlled to monitor each zone by scanning the zones in a predetermined sequence. The microprocessor is associated with the key pad. According to the present invention, the key pad is accessed by a serviceman who inserts a given code into the key pad indicative of a one man test mode. The microprocessor recognizes the selection of this mode and therefore anticipates receiving an alarm condition due to the fact that the serviceman, after accessing the key pad, will enter a selected zone to provide an intentional alarm at that zone.

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: A device for monitoring combustion efficiency of a burner with a burner fe has an acoustic sensor probe positioned within the burner, flame signature generating circuitry responsive to the acoustic probe, means for correlating flame signatures with known optimum efficiency characteristics to yield an indication of relative combustion efficiency, and output means for display of the relative combustion efficiency.

Abstract: The invention discloses a method and an apparatus for explosion protection of plants, pipelines and the like by monitoring chronologically successive values of the system pressure in the potentially explosive area and by comparing these values with a predetermined pressure threshold, where the exceeding of this pressure threshold is used as a triggering criterion for initiating explosion protection provisions. According to the invention, instead of predetermining a constant value as the pressure threshold, the pressure threshold is updated continuously in accordance with the system pressure prevailing at that time. As a result, the pressure threshold can be set with a smaller safety margin above the system pressure than before. Brightness and temperature thresholds may also be used singly, or together with pressure in any combination in continuous value monitoring.

Abstract: A smoke detector having variable sensitivity to smoke levels and using one button both to test the smoke detector and actuate a mode of diminished sensitivity to smoke levels. The smoke detector is operable in a normal sensitivity mode and a diminished sensitivity mode with rapid switching between the modes. The sensitivity to smoke levels is substantially constant when in either the normal or diminished sensitivity mode.