Abstract: Flame detecting apparatus is disclosed for detecting the presence of ultraviolet radiation indicating the presence of a fire. The apparatus itself includes a housing with at least one aperture, an alarm and a UV detector extending through the aperture for triggering the alarm, and protective wings disposed about the aperture to protect the UV detector without blocking same from the ultraviolet radiation.

Abstract: An apparatus and method for sensing electro-magnetic radiation and analysing the resultant electrical signal waveform, in order to determine whether the radiation originates from a fire condition, monitors variations in the signal waveform over a predetermined period of time. The amplitudes of the successive transitions in the waveform and the elapsed time between the transitions are measured. Two two-dimensional matrices are produced. The first of these is made up of a plurality of co-ordinate points each corresponding to a respective pair of successively occurring signal transitions. The position of each such point in the matrix is dependent on the respective amplitudes of the two transitions making up each pair. The second matrix is also made up of a plurality of co-ordinate points each corresponding to a respective pair of the signal transitions.

Abstract: In a flame detecting apparatus for detecting the flame of fire or the like using a sensor 1, a signal processing unit 3 includes a span counting section 5 for dividing a time base into several time spans, each having a predetermined time interval, and counting the number of signals output from the sensor 1 as a count value for each span, a count value storage section 6 for storing the count value for each span output from the span counting section 5, and an calculation section 7 for judging the occurrence of flame by taking into account the count values counted for the past spans which have been stored in the count value storage section 6, as well as the count value of the latest span, when the count value of the latest span is output from the span counting section 5.

Abstract: In fire detector apparatus for monitoring an extended area from an elevated location, and especially for detecting forest fires, a scanning assembly (1) has azimuthal freedom of movement. A row of adjoining infrared detector element pairs (S, S') is disposed on a common support (7) in the focal plane of a reflector (6). Detector extent or area increases from the optical axis upward, and the detectors are connected with decreasingly sensitive circuitry. As a result, detection areas having different elevations have nearly equal distance range, and detection sensitivity is essentially independent of distance so that a remote forest fire is detected with the same degree of certainty as one close by. For the elimination of false alarms due to diffuse thermal radiation, detector elements are arranged in pairs, side-by-side on the same support (7), and connected in differential circuitry.

Abstract: The presence of a burner flame, in a multiple burner installation, is monitored by sensing a signal indicative of the spectrum of the fluctuating component in the radiation of the flame over a range of frequencies. In the lower frequency range a measure is obtained of the difference of signal strength at two predetermined frequency levels. The signal strength is also measured at a higher frequency. At the higher frequency there is a significant difference in signal intensity between the flame-on and flame-off conditions, while the change of signal strength between the spectra of flame-on and flame-off conditions in the lower frequency range is sensitive to frequency. By processing the two measures together they can augment each other and produce an enhanced change of signal between flame-on and flame-off conditions, making detection easier.

Abstract: A flame detecting and alarm system has a ultraviolet radiation sensor (UV sensor) which detects ultraviolet radiation and outputs sensor output pulses. The spacings of the sensor output pulses represent amounts of energy of the ultraviolet radiation detected by the UV sensor. Each pulse spacing of the sensor output pulses is measured, and the pulses are regarded as "continuous" if the pulse spacings are less than a predetermined time period. The presence of a predetermined number of "continuous" sensor output pulses is interpreted as a recognition of a flame, and an alarm is activated.

Abstract: A light off detecting arrangement for sensing the presence of a flame in a region such as the afterburner of a turbine engine is disclosed. An optical focusing device such as a lens or mirror is located near a quartz window adjacent the afterburner for concentrating electromagnetic radiation emanating from the region. An optical (fiber optic) pathway receives the concentrated electromagnetic radiation from the optical focusing device and conveys that radiation thru the optic filters to an opto-electrical converter for converting incident electromagnetic radiation to electrical signals. A frequency selective optical device such as an infrared filter is interposed between the optical focusing device and the opto-electrical converter for insuring that a preselected portion only of the electromagnetic radiation emanating from the region is converted to electrical signals.

Abstract: A thermal detector arrangement includes a number of channels, each including a collimator for collimating incident radiation to a respective optical filter. Each optical filter has a respective radiation passband characteristic with one having a passband spanning the passbands of all of the other optical filters. The radiation passed by each optical filter is passed to a thermal detector, which preferably is in the form of a thermally isolating membrane acting as a radiation absorbent cavity and supported by a semiconductor substrate. The output signals from the thermal detectors are multiplexed, amplified by an amplifier having voltage offset compensation and digitally processed to provide an indication of a fire to be sensed.

Abstract: A fire-perimeter, temperature-differentiating mapping system for creating a temperature-level-differentiated, visually readable outline of a ground fire, which outline is suitable for in-scale registered overlay of a related topographic map for the purpose of aiding firefighters in determining where best to allocate fire-fighting resources.

Abstract: A fire sensing system, a process for sensing a fire and an environment monitor are disclosed. The system includes infrared sensors with sensing wavelength bands sensing an infrared radiation from an infrared source. One of the sensing wavelength bands is a CO.sub.2 -molecular resonance radiation wavelength band. The system determines whether a disastrous fire occurs or not on the basis of outputs of the sensors and a change in a ratio of the outputs. The process computes the temperature of the infrared source from a ratio of outputs of infrared sensors with at least two sensing wavelength bands of an infrared radiation from a monitored area, produces the intensity of infrared radiation of either of the bands from the computed temperature and computes a heating area from the intensity and the output of a corresponding infrared sensor. The process determines the progress of a fire.

Abstract: A method and apparatus for determining and indicating the flame quality, or efficiency of the air-fuel ratio, in a fixed firing rate heating unit, such as an oil burning furnace, is provided. When the flame brightness falls outside a preset range, the flame quality, or excess air, has changed to the point that the unit should be serviced. The flame quality indicator output is in the form of lights mounted on the front of the unit. A green light indicates that the flame is about in the same condition as when the burner was last serviced. A red light indicates a flame which is either too rich or too lean, and that servicing of the burner is required. At the end of each firing cycle, the flame quality indicator goes into a hold mode which is in effect during the period that the burner remains off. A yellow or amber light indicates that the burner is in the hold mode. In this mode, the flame quality lights indicate the flame condition immediately before the burner turned off.

Abstract: A heating system controller is suitable for controlling a heating system based on a plurality of sensed control signals representing control parameters. The heating system controller has a first input suitable for being coupled to provide a control signal. The heating system controller also includes a sensor, coupled to the first input, for sensing control signals at the first input, the control signals having a first pattern, a second pattern, or a third pattern detected over at least two successive time periods. The heating system controller includes a control mechanism, coupled to the sensor for controlling the heating system based on the first, second and third patterns. The control mechanism causes the controller to change modes when the third pattern is sensed.

Abstract: An explosion suppression system and triggering apparatus therefor are provided for quenching gas and dust explosions. An electrically actuated suppression mechanism which dispenses an extinguishing agent into the path ahead of the propagating flame is actuated by a triggering device which is light powered. This triggering device is located upstream of the propagating flame and converts light from the flame to an electrical actuation signal. A pressure arming device electrically connects the triggering device to the suppression device only when the explosion is sensed by a further characteristic thereof beside the flame such as the pioneer pressure wave. The light powered triggering device includes a solar panel which is disposed in the path of the explosion and oriented between horizontally downward and vertical. Testing mechanisms are also preferably provided to test the operation of the solar panel and detonator as well as the pressure arming mechanism.

Abstract: A directionally-sensitive flame detection apparatus and method for determining the presence of flame in a combustion chamber zone of a gas turbine. A radiation detector is coupled to the monitored combustion zone by a radiation collimator having mechanically-lowered internal reflectance so as to enhance the effective collimation angle. In this manner, a narrowed detector view angle is provided that is substantially independent of radiation wavelength or the material properties of the collimator tube.

Abstract: A method of detecting flame within a region where flame is expected. Radiation emissions from the region are measured within selected portions of the visible and infra-red frequency bands. Spectral characteristics of the two measurements, including their auto spectra, coherency and transfer function, are derived. The derived spectral characteristics are compared with prestored spectral signatures representative of the spectral characteristics of radiation emitted from the region within the selected portions of the visible and infra-red frequency bands while known flame conditions prevail within the region--thereby estimating the deviation of the derived spectral characteristics from the prestored spectral signatures. The deviations aforesaid are compared with predetermined threshold alarm values to assess the presence or absence of flame.

Abstract: In one embodiment a bundle of optic fibers of different lengths are inserted through the case wall of a solid fuel or a hybrid rocket motor and extends through the wall of the fuel grain to the edge of the bore in center thereof. As the grain burns in a normal manner, from the center toward the outer periphery of the case, the bright flame of ignition is seen at the end of the fiber optic fiber adjacent to the flame. The length of each fiber in the bundle is used to determine the burn rate and amount of grain left to ignite. In another embodiment different length fibers of a bundle are looped into the grain and back to the exterior of the case and light emitting diodes are positioned at one end of each fiber with a light-detecting means at the other end. The light through the diodes is monitored to detect a no-light condition which exists when a fiber is destroyed by the burn. In yet another embodiment a single optic fiber is used with a light source and a light reception means at one end.

Abstract: The presence of a flame from a burner is determined by analyzing the signal produced by a radiation sensor aimed at a burner. Specifically, a Fourier transformation is applied to the signal producing amplitude values for a spectrum of component frequencies produced by changes in the power of the flame over time. A logarithmic value is derived for each of the amplitude values. The degree of linearity of the distribution of the component frequency logarithmic amplitude values provides an indication of the flame presence. Several parameters, including integrated linear error, linearity regression correlation and slope difference, provide an indication of the degree of linearity. A plurality of values for each of these parameters are produced during an interval of time.

Abstract: A circuit for detecting presence of a flame receives a flame signal from a standard photocell positioned to receive radiation from the flame and digitally processes the amplitude variations in the photocell's output to sense for the presence of frequencies near a frequency which is characteristic of a flame. The frequencies substantially higher than the characteristic frequency are filtered from the signal, and the remaining signal is sampled at a frequency which is preferably four times the characteristic frequency. The samples are converted to digital values and processed using a discrete Fourier transform. If the value resulting from the transform operation exceeds a preselected value, presence of a flame is essentially certain. Such digital processing allows use of a dedicated microcircuit or a microprocessor for the flame sensing function and avoids the need for many large discrete components.

Abstract: A fiber optic fire and overheat sensor system 10 includes a fiber optic cable 12 having a lens 14 at a distal to direct radiation from a fire 16 into the cable 12 and to a radiation detector 18 disposed at a proximal end of the cable 12. Detector 18 is coupled to a fire sensor 19. The detector 18 is sensitive to two wavelength bands including a short wavelength band of approximately 0.8 to approximately 1.1 microns and a long-wavelength band of approximately 1.8 to approximately 2.1 microns. A controller 21, such as a microprocessor, analyzes the fire sensor 19 output signals which correspond to the two spectral bands to determine if a fire is present. The system 10 further includes a body of fluorescent material 20 disposed at the distal end of the cable 12. The material 20 can be interposed between a reflecting surface, such as a mirror 22, and a lens, such as a collimating lens 24. A fiber optic coupler 26 and 26a launches radiation from a source 28, such as a laser diode, into the fiber optic cable 12.

Abstract: A system for detecting an overheat condition in aircraft preferably includes two control units each connected to eight thermal imaging modules. The thermal imaging modules monitor the cargo by for an overheat condition and if any module detects an overheat condition, the control unit verifies the overheat condition and then triggers an alarm. The control units execute routines to monitor and test their operational status and that of each thermal imaging module. The control units are connected to the aircraft electronics to indicate the location of an overheat condition or any malfunctioning control units and thermal imaging modules. The thermal imaging modules are identical to each other and include an infrared detector, a rotating optical assembly, threshold circuitry and a motor. The optical assembly is rotated by the motor to provide the detector with a conical field of view. The optical assembly focuses the radiation in the cargo bay on the infrared detector.

Abstract: A fiber optic fire detection and temperature measurement system 10 includes a fiber optic cable 12 having a lens 14 at a distal to direct radiation from a fire 16 into the cable 12 and to a radiation detector 18 disposed at a proximal end of the cable 12. Detector 18 is coupled to a fire sensor 20. The detector 18 is sensitive to three wavelength bands including a short wavelength band of approximately 0.8 to 1.1 microns and a long-wavelength band of approximately 1.8 to 2.1 microns. A controller 22, analyzes the fire sensor 20 output signals which correspond to the two spectral bands to determine if a fire is present. The fiber optic conductor of cable 12 includes an optical filter 32 having a temperature dependent radiation transmission characteristic. Radiation from a fire passes via cable 12 to the detector 18.

Abstract: A fiber optic fire detection and temperature measurement system 10 includes a fiber optic cable 12 having a lens 14 at a distal to direct radiation from a fire 16 into the cable 12 and to radiation detector 18 disposed at a proximal end of the cable 12. Detector 18 is coupled to a fire sensor 20. Detector 18 is sensitive to three wavelength bands including a short wavelength band of approximately 0.8 to 1.1 microns, a mid-wavelength band of approximately 1.3 to 1.5 microns and a long-wavelength band of approximately 1.8 to 2.1 microns. A controller 22, analyzes the fire sensor 20 output signals which correspond to the two spectral bands to determine if a fire is present. The fiber optic conductor is doped with a material selected for its temperature dependent fluorescent emission characteristics. Radiation from a fire passes via cable 12 to the detector 18. A pulse of radiation from source 28 passes from a coupler 26 and 26a to the cable 12.

Abstract: A combustion control device capable of detecting a self-discharge state caused by a failure of an ultraviolet ray detecting tube by interrupting flames from a combustion mechanism to an ultraviolet ray detecting tube by opening and closing a shutter, integrating, by an integrating circuit, detection signals from this ultraviolet ray detecting tube only when the shutter is closed, comparing the result of this integration with a preset judgement level by use of a first judgement circuit, and determining a failure by comparing a result of this comparison with a preset failure judgement frequency by use of a second judgement circuit, thereby improving maintainability.

Abstract: A flame detector has a sensor for producing a digital waveform representing a flickering flame. Its turning points are detected and the magnitudes between successive such points are measured. The value of each such magnitude is plotted on a graph whose horizontal axis represents the current value and whose vertical axis represents the immediately preceding value. Points are produced lying in regions away from the diagonal and from the axes. If the detected waveform originates from a regularly varying interfering source, the corresponding points will lie on or near the diagonal. If the interfering source is a waveform undergoing step changes, the corresponding points will lie adjacent to the axes. In this way, discrimination between flames and interfering sources of radiation can be made.

Abstract: For the detection of heat sources within an area to be maintained under surveillance, several scanning units at different scanning stations are linked to a common radiation sensor by respective optical fibre transmission elements. A gating means, such as a rotary mask with an opening, is indexed stepwise to gate each transmission element in turn to the common sensor.

Abstract: A method for producing reflectors in a continuous length of optical fiber is disclosed. The present process includes the steps of preparing the ends of two or more optical fibers, placing one or more of these fibers in a vacuum system and applying a metallic or dielectric coating to the fiber ends, and then fusing the prepared, coated ends of the fibers together until the reflectivity of the region reaches a desired value.

Abstract: A flame detector that comprises a housing adapted to contain a flame sensor and circuitry for processing signals produced by the sensor; the housing has a predetermined outer diameter, and a thin, highly thermally reflective coating is adhered to an outer surface of the housing to shield the sensor and circuitry from high ambient temperatures, whereby the detector is operable at the high ambient temperatures while having an outer diameter that is substantially the same as the predetermined diameter.

Abstract: A method of detecting flame within a region where flame is expected. Radiation emissions from the region are measured within selected portions of the visible and infra-red frequency bands. Spectral characteristics of the two measurements, including their auto spectra, coherency and transfer function, are derived. The derived spectral characteristics are compared with prestored spectral signatures representative of the spectral characteristics of radiation emitted from the region within the selected portions of the visible and infra-red frequency bands while known flame conditions prevail within the region--thereby estimating the deviation of the derived spectral characteristics from the prestored spectral signatures. The deviations aforesaid are compared with predetermined threshold alarm values to assess the presence or absence of flame.

Abstract: An optical fire detection system that uses cosmic radiation or a radioactive source to test whether the ultraviolet light detector tube operates properly and includes self test logic to independently verify that the detector electronics are functioning properly. A high voltage is applied across the ultraviolet light detector tube to produce pulses of current when radiation is present. A pulse rate discriminator circuit measures the current pulses and outputs a fire signal if the pulse rate is equal to or greater than the pulse rate produced by ultraviolet radiation from a fire. A background count circuit also measures the current pulses from the ultraviolet light detector tube to test whether the ultraviolet light detector tube is operational. At least one current pulse should be detected within a specified time because the detector tube senses cosmic radiation or radiation from the radioactive source.

Abstract: An alarm system for warning of a creosote chimney fire hazard, having both means to produce a visible alarm when the creosote temperature is nearing the creosote flash point, and means to produce an audible alarm when light from actual ignition of a creosote fire is detected. The invention also provides means to discriminate against detection of wood fire light, to minimize false alarms.

Abstract: A flame detector, for use with a photocell which produces a flame signal when the photocell is exposed to a flame, is used for detecting the presence of a flame. An input circuit is coupled to the photocell for receiving and buffering the flame signal. The buffered flame signal is filtered and amplified in a filter. An output circuit further amplifies the filtered flame signal providing an output flame signal. A switch is also used in the flame detector for substantially short circuiting the flame signal to a known value upon receiving a switch-close signal from either a test computer or from a hot refractory detection circuit. A flame-out condition is detected by the hot refractory detection circuit which generates an HRD signal causing the flame signal to be substantially short circuited to a known value thereby eliminating a false flame signal caused by hot refractory shimmering.

Abstract: A flame detecting device indicates the presence or absence of a flame. The detecting device includes both an IR detector for sensing the IR frequencies of the flame and a UV detector for sensing the UV intensity of the flame. Information is stored defining IR frequency and UV intensity standards. A microcomputer is operatively connected to the IR and UV detectors and compares the two detector outputs to the two respective standards in accordance with a program establishing defined conditions in terms of IR frequency and/or UV intensity that must be met for a flame present or flame absent signal to be rendered on a bar graph display.

Abstract: In an infrared flame detector system an infrared photodetector is positioned to receive infrared radiation from the flame to be detected. The output of the infrared flame detector is amplified with a gain readily switchable between two different gain values. The amplified output signal is filtered by a programmable high pass filter, in which the corner frequency can be selected to have different values and is readily switchable between two different values to correspond with different fuels generating the flame being detected. The output of the programmable filter is full wave rectified to provide a DC signal level corresponding to the AC signal generated across the photodetector. This DC signal level is compared with a reference signal voltage selected to correspond with the signal voltage produced when no flame is present, to provide an indication of the presence or absence of a flame.

Abstract: A method of detecting fires utilizing its flicker frequency spectrum provides a standard theoretical flicker frequency spectrum which is compared to the real time spectrum over a 2 second time period. The comparison includes whether or not the real time fire spectrum deviates from the idealized fire spectrum by a minimum amount and has further discrimination against false fire signals, including the extent of time of the real time spectrum is outside a predetermined window and a limit on maximum deviations.

Abstract: A method and improved apparatus for generating and transmitting the distinguishing radiation characteristics of a fire, an ignition and fire, or an ignition without a fire, to a fire sensing system under test are disclosed. Varying radiant energy attributes of a fire, and in particular a hydrocarbon fire such as might be encountered in a vehicle fuel or engine compartment are safely generated by a blackbody transmitter 100, an ultraviolet transmitter 200 and an ignition flash transmitter 300, having appropriate radiation sources. The radiation sources may be conveniently assembled into a palm-sized radiation "head" 101. The transmitters may be selected sequentially to test installed fire sensing systems in aircraft or vehicles or during manufacture where the environment does not permit the use of an actual fire.

Abstract: A fire detection system has a detector for sensing optical radiation from a spark or flame or hot spot and an optical waveguide comprising an elongate hollow tube, having an inlet end portion for placement in a hostile, hazardous environment, and having an outlet end portion for emitting light rays to the detector and for placement in a benign, non-hazardous environment, and having a reflective inner surface forming a passage for transmitting the optical radiation from the tube inlet end portion to the tube outlet end portion by successive internal reflections.The elongate hollow waveguide tube is sealed at the inlet end portion by a lens which admits the optical radiation to the tube; and at the outlet end typically by the detector. The sealed tube is filled with an inert gas, such as nitrogen, which helps to maintain the reflective interior surface of the tube.

Abstract: An apparatus is provided for automatically unlocking the guard bars on a window in response to the output signal of a fire detection device. In a preferred embodiment a smoke alarm having a pair of relay-controlled contacts is used in conjunction with a solenoid arrangement to unlock the window bars. Power to the smoke detector and the solenoid circuit is supplied by a rechargeable battery, so that in the event of power failure the automatic window bar unlocking apparatus continues to operate.

Abstract: An apparatus for monitoring a flame which emits light, the apparatus comprising: (a) a detector for detecting the light and outputting a signal corresponding to the light; (b) a casing for enclosing the detector, the casing including an aperture for the light going to the detector; (c) a blower for supplying air to the casing; and (d) a windmill for periodically shuttering the light to the detector with a shuttering frequency, the windmill being driven by the supplied air.

Abstract: A flame scanning system for monitoring a combustion process by detecting flame emission characteristics in the ultraviolet light spectrum. A metered relative flame intensity signal, flame-off signal, and flame-on signal are provided. A self-diagnostic feature produces a flame marginal signal indicative of substandard flame operation; a tube marginal signal indicative of imminent UV tube failure is also produced. A scanner shutter mechanism includes a check failure feature for detecting UV tube failure. An electronic assisted sighting indicator is also included to assist during on-sight scanner positioning and to provide optimum scanner placement.

Abstract: This invention relates to an automatic fire extinguishing equipment adapted to direct a nozzle towards the position of a flame starting within a supervising zone so as to discharge a fire extinguishing liquid to extinguish the flame, which equipment comprises a flame detecting apparatus including a detecting element for detecting a flame and device for scanning and driving the detecting element in a horizontal direction and a vertical direction, for searching the supervising zone and outputting data concerning the flames; a storage section for storing the detection data from the flame detecting apparatus; a fire extinguishment controlling section which decides the sizes of the distributed flames on the basis of the storage data from said storage section; a nozzle assembly including the nozzle and device for controlling the direction of the nozzle in response to a control from the fire extinguishment controlling section.

Abstract: A system for detecting a flame or droplets of burning polypropylene in an area below an upper surface of a conventional wet bench used in semiconductor production includes at least one sensor, a threshold detector, a discrimination, a counter and a latch. The sensor detects radiation generated by activity in the area and for generating a sensor signal in response to the detected radiation. The threshold detector determines whether the activity has a cross-sectional area which exceeds a predetermined threshold area. The discriminator determines whether the activity displays a flicker rate or a droplet rate that is within the predetermined flicker rate range.

Abstract: A flame detecting apparatus and a flame detecting method which utilizes a flame detector having a directivity and provided with a photodetector such as a photodiode or a phototransistor which produces a photo-output in response to the intensity of light incident thereupon. The flame detector is scanned sequentially in the horizontal and the vertical direction within a supervisory region. When a photo-output from said flame detector obtained in the horizontal or vertical scanning by said scanning means exceeds a predetermined threshold value, one of the horizontal and the vertical scanning is suspended, while repeating the other, vertical or horizontal, scanning at the same horizontal or vertical position several times. Flame determination is made when the changes in the photo-outputs, which is obtained through the repeated scanning, exceed a predetermined value and they last over a predetermined scanning angle.

Abstract: Apparatus for sensing the ex(i)stence of a fire and providing a warning, if desired, with improved discrimination against the possibility of false alarms. Dual channel detectors are used, one detector being set to respond to incident radiation having a wavelength in the range of 0.8 to 1.1 microns while the other wavelength range is significantly displaced therefrom, being selected for wavelengths in the range from 14 to 25 microns. Reliability of true signal detection is further improved by the provision of separate flame flicker bandpass filters in the respective channels, these bandpass filters being set for different passbands. Circuits providing ratio discrimination, threshold detectors and delay circuitry are combined with the dual spectrum detectors and disparate flicker frequency filters to achieve improved performance.

Abstract: A fire detection system discriminates between a HEAT round that does not initiate a secondary fire and a HEAT round which does initiate a secondary fire. The system of the invention measures the peck intensity of a penetrating HEAT round in order to determine a secondary threshold level which is subsequently utilized to detect a resulting hydrocarbon fire. Also, the system performs a statistical analysis of the slope of the round thermal signature to determine if a secondary fire may be occurring.

Abstract: A fire sensor can perform a sophisticated analysis of the outputs of radiant energy detectors, while minimizing size, weight, and cost, by employing a microprocessor to analyze the detector outputs. In a preferred embodiment, an Intel 2920 Signal Processor is utilized as the microprocessor.

Abstract: A system and method for detecting a fire source in a supervised region by means of fire detectors which effectively scan all over such region. A plurality of reference fire sources of the same geometric shape of the minimum size to be regareded as a fire are assumed to be located in successive predetermined position on the floor of the supervised region. Vertical control means successively sets the vertical deflection angles of each detector along the respective straight lines from each detector which graze by the upper end of the respective fire sources and to the lower end of the succeeding fire source. The system also comprises horizontal control means for causing the detectors to horizontally scan the supervised region. Upon detection of a fire, the detectors provide fire detection signals to a central processor unit which then actuates a spray nozzle to direct fire extinguishing fluid on the fire.

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: A flame detector in which an infrared ray sensor having a specific infrared ray sensitivity and a visible ray sensor having a specific visible ray sensitivity are provided and output signals from both sensors are amplified by amplifiers, which in turn provide output signals to a phase discriminator circuit, the output signal from the amplifier for the infrared sensor output being also fed to a rectifier circuit for rectifying only a predetermined level or higher portion of the amplified output; an output signal from the rectifier circuit is fed to an integrator circuit and also fed to another integrator circuit through a switch which is opened when the output level of the phase discriminator circuit is "H"; then output signals from the integrator circuits are compared by a comparator and at the same time the output signal from said another integrator circuit is compared with a preset value by a comparator; and output signals from both comparators are fed to a control circuit which issues an alarm when the out

Abstract: A fire and explosion detection and suppression system protects a hangar within which may be stored jet aircraft whose engines may be run up particularly in the re-heat mode. Two radiation sensors are mounted within the hangar and detect for at least predetermined amounts of radiation of predetermined and different types (e.g. one sensor may be a UV sensor and the other may be an IR sensor). When they simultaneously detect sufficient radiation, they operate an AND gate. This fires off suppressor units. To prevent false alarms due to radiation emitted by a running jet engine or a jet engine running in re-heat mode, such a running jet engine is sensed by a transducer responsive to the emitted acoustic or vibrational energy. This blocks the AND gate.

Abstract: A fire and explosion detection and suppression system protects two physically adjacent zones in each of which there is a UV sensor and an IR sensor. In each zone, simultaneous detection, by the pair of sensors, of sufficient respective levels of UV and IR causes an AND gate to set off suppressor units to discharge suppressant into the zone being protected. Some of this suppressant may drift into the adjacent zone and may attenuate UV radiation in that zone. Thus, for at least a temporary period, that zone may be incapable of detecting a subsequently occurring fire or explosion. Therefore, by means of a latching circuit the output signal of an operating one of the AND gates temporarily renders the circuit of the adjacent zone capable of operating independently of UV radiation.