Abstract: A portable temperature data recorder for temporarily storing plural sets of temperature data representative of temperatures at a single location or at different locations, and automatically transferring the stored temperature data to a data processing unit. The portable recorder has a connector for connection thereof to the data processing unit. The portable recorder may further have a connector for connection thereof to a stationary temperature detector or thermometer installed at each measurement location. Alternatively, the temperature recorder incorporate a temperature detector for measuring the temperatures at the measurement locations. A clock circuit may be provided in the portable recorder, so that the temperature data may be stored together with measurement time data. The temperature detector may be a radiation thermometer provided at the measurement location, or built in the portable recorder.

Abstract: In conventional methods of quantitative hydrocarbon analysis in gaseous sles by means of infrared transmission, systematic inaccuracies may be found which are caused by changes in the composition of the components contained in the sample. Such inaccuracies typically amount to 10 to 30% of the measured value, with occasional rises of up to 100%. In order to eliminate this disadvantage the invention proposes that for determining the total mass of gaseous and condensed hydrocarbons radiation be used with a frequency band whose integral infrared absorption has approximately the same value for each of the main hydrocarbons present.

Abstract: Temperature is measured by launching pulses of light into an elongate optical fibre and determining the temperature at positions along the fibre from the intensity of light scattered at those positions. The input pulses can have either the same or two different wavelengths, and the scattered light can be either Raman or Brillouin scattered and either forward scattered or backscattered. One position along the fibre can be maintained at a known temperature in order to provide a reference for other calculations. In particular embodiments the temperature is derived from the ratio between the intensities at two anti-Stokes wavenumber shifts or between an anti-Stokes scattered and a Rayleigh scattered intensity measurement. Otherwise the intensities of Stokes and anti-Stokes shifted Brillouin back scattered light can be used to derive the temperature.

Abstract: An intruder detection system is provided with circuitry for reducing the risk of false alarms from spurious sources. Such circuitry comprises a pulse generator for producing current pulses of predetermined pulsewidth and amplitude each time the output of an intrusion detecting element exceeds or falls belows a preset threshold level, an integrating circuit for integrating the output of the pulse generator, threshold sensing means for activating an alarm when the integrator output exceeds a preset level, and a timing circuit for establishing a predetermined time interval and for discharging the integrating circuit in the event the integrator output fails to exceed such preset level within such predetermined time interval. According to a preferred embodiment, means are provided for resetting the time interval each time the detector output exceeds or falls below the selected threshold level.

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: For reducing the susceptibility to false alarms and for increasing the detection probability of a passive infrared detector, the actual signals obtained from a first sensor element are continuously compared in a correlator with reference or set signals stored in a read-only memory and/or with the actual signals obtained from a second sensor element monitoring the near region. The correlator delivers an output signal which corresponds to the correlation of both signals which are compared with one another. An alarm signal is triggered when the correlation exceeds a predetermined value, for instance 0.7, and the amplitude has reached a predetermined threshold. The infrared detector affords high security against giving of false alarms and a high detection probability, even in the presence of signals possessing a great amount of noise, but also delivers an alarm signal in the event the detector is attempted to be sabotaged, for instance by covering the inlet optical system.

Abstract: A method for detecting and precisely locating features such as susceptor surfaces, wafers and surface depressions and elevations, is disclosed. A modified high angle, infrared, crossed-optics-pair sensor unit is used, as well as both perpendicular and parallel scanning.

Abstract: An accessory for use with spectrophotometers for conducting IR emission spectra analyses of samples comprising a heated highly-reflecting surface for receiving the sample, an apertured reflecting mask located over the sample, and a curved reflector for collecting emissions from the sample via the aperture over a large solid angle to increase the signal-to-noise ratio.

Abstract: Selective thermal examination of a target is provided by scanning the field of view of an infrared detector over predetermined areas of a target. The selection is made by a plurality of infrared fibers having first and second ends with the first ends being stationarily mounted in a fixed array suitable for being scanned by the detector or a detector coupled to each first end which are electrically scanned, while the second ends of the infrared fibers are directed by the user to selected areas of the target which are desired to be thermally examined. The infrared detector or detectors are then scanned over the first ends of the infrared fibers in the fixed array for sequentially thermally examining the selected areas of the target. The selected areas may be changed simply by rearranging and redirecting the second ends of the infrared fibers with respect to the target areas desired to be examined.

Abstract: A method of more accurately measuring the true surface temperature of metal alloy objects without contacting the same. The surfaces of the objects have unknown emissivities that change and that are less than unity. The method includes the step of providing objects having surfaces that radiate infrared energy. The radiated energy is measured at two wavelengths, and a first measurement is provided that is a function of the ratio of the energies at the two wavelengths. The radiated energy is also measured at a single, narrow band wavelength, and a second measurement is provided that is a function of the radiated energy. The two measurements are then electrically combined to provide measurements of radiated energy and thus temperature measurements that are or at least are closer to the true temperature than either of the first or second measurements.

Abstract: An alarm device is built into electrical equipment such as a portable radio receiver or tape recorder and connected to a loud speaker unit for producing an alarm sound by sensing infrared rays emitted from an intruder and sensed by an infrared ray detector included therein.

Abstract: In the present invention, the temperatures of cooling passages in a gas turbine engine blade are changed, as by forcing a heated gas through them. The infrared signatures of the channels are measured during the initial temperature transient of the channels and the signatures are compared with a reference. The reference may be the signature of other channels on the same blade.

Abstract: A cross-correlation fire sensor circuit includes detectors responsive to heat and light radiation, respectively. Electrical signals from the detectors are processed in two distinct channels through low pass filters and samplers. The sampled signals from the two channels are multipled together and the products are summed over a selected interval to provide a correlation function. This function is compared with an adjustable threshold to provide an indication of fire sensing. The circuit is also included as an adjunct to an existing system to provide improved sensitivity for fire sensing in the presence of noise and enhanced discrimination against false alarms. A ratio window detector circuit is disclosed as an alternative cross-correlator for detected radiation.

Abstract: In the manufacture of a multilayer polymer film, the thickness and degree of orientation are simultaneously measured. A beam of infrared radiation having predetermined wavelengths is either transmitted through or reflected by the polymer film to be measured and received by a photodetector. The photodetector provides an electrical output signal which can be analyzed to determine the thickness and degree of orientation.

Abstract: An intrusion detection system includes a plurality of infrared radiation sensitive elements, each of which comprises first and second spaced electrodes between which polarized pyroelectric material is positioned, each element being operative to produce a voltage proportional to the rate of change of infrared radiation incident thereon. The elements are closely spaced to one another and cover substantially all of at least one surface of the pyroelectric material. Multiple fields of view of areas under surveillance are fully covered (with negligibly small gaps). Alternate sensor elements are connected to a first amplifier channel and the other sensor elements are connected to a second amplifier channel. Coincidence means produces an alarm output in response to concurrent intruder signal generation by both of the amplifier channels.

Abstract: A method and apparatus for detecting submillimeter or IR radiation is disclosed. A rare gas, such as xenon, is supplied at its ground state via a pressurized cylinder and an adjustable leak valve into a cryogenically-cooled detection area. The ground state of xenon is double-photon excited to a particularized level of the Rydberg series by a resonance lamp and a laser. The doubly-excited gas is then further excited by the radiation to be measured. A field ionization and an ion measurement indicative of the radiation intensity is achieved.

Abstract: In one exemplar embodiment, a method and apparatus are disclosed for detecting the accumulation of frost on the evaporator coils of refrigerating equipment. An emitter or source of electromagnetic radiation having a selected narrow band of wavelengths and a selected intensity directs the electromagnetic radiation at the frost. A detector, spaced from the frost and emitter, receives the narrow band of electromagnetic radiation and detects changes in the intensity of the radiation due to absorption or scattering of the radiation by the frost in a relation proportional to the thickness of the frost. Control means responding to the detected change in intensity of the radiation is provided to initiate a defrost cycle and control the accumulation of the frost on the evaporator coil surfaces. Other embodiments of the invention include a liquid level detector and a physical state phase change detector.

Abstract: In one exemplar embodiment, a method and apparatus are disclosed for detecting the accumulation of frost on the evaporator coils of refrigerating equipment. An emitter or source of electromagnetic radiation having a selected narrow band of wavelengths and a selected intensity directs the electromagnetic radiation at the frost. A detector spaced from the frost and emitter receives the narrow band of electromagnetic radiation and detects changes in the intensity of the radiation due to absorption or scattering of the radiation by the frost in a relation proportional to the thickness of the frost. Control means responding to the detected change in intensity of the radiation is provided to initiate a defrost cycle and control the accumulation of the frost on the evaporator coil surfaces. Other embodiments of the invention include a liquid level detector and a physical state phase change detector.

Abstract: A pyrometer for determining the temperature of a surface in the presence of reflected radiation has two infrared radiation sensors, each responsive to different wave length, positioned to receive radiation from the surface. An adjustment factor is developed from sensor response signals when reflected radiation and surface temperatures are the same, and is combined with sensor response characteristics over a range of surface and sensor indicated temperatures to develop a correction factor which when multiplied by the indicated temperature provides the actual surface temperature.

Abstract: An alarm device responsive to entering or trespassing comprising:(a) a sensor circuit, including an infrared ray sensor, producing an output having positive and negative peaks based on outputs of said sensor being produced when a target to be sensed passes within the region of vision monitored by said sensor,(b) a level detecting circuit comprising a first detector producing an output when the positive peak of the output fed from said sensor circuit exceeds a predetermined level, and a second detector producing an output when the negative peak of the output fed from said sensor circuit exceeds a predetermined level,(c) a timer circuit comprising a first timer producing an output which continues for a predetermined time interval or above from a time at which the output of said first detector is produced, and a second timer producing an output which continues for a predetermined time or above from a time at which the output of said second detector is produced,(d) an AND circuit comprising a first circuit produc

Abstract: The invention relates to a system for detecting sources of heat, comprising a certain number of watching stations distributed within the area to be watched, comprising an infrared radiation detector located at a level above the area to be watched and connected to a motor for imparting to the detector a periodic angular, step-by-step motion, and a device for logic processing of the information received by the detector and for transmission through the telephone link, a central station being equipped with a data processing device including a memory in which the known sources of heat of the area to be watched are recorded or entered.

Abstract: There is disclosed a fire and explosion detection system and method comprising at least one first channel including a photocell and accompanying electronics for converting incident radiant energy of a first narrow band of wavelengths into a first electric signal; and, at least one type of second channel means including a photocell and accompanying electronics for producing a second electrical signal proportional to incident radiant energy of a second narrow band of wavelengths corresponding to background, black body emissions. The signal outputs of these two channels are further processed by a ratio detection circuit which produces yet another output electrical signal when the ratio of the two input signals exceeds a predetermined number. The output of this ratio detection circuit is further processed by a so called flicker frequency detection circuit which counts pulses indicative of the flicker frequency of the fire and gives a first warning if that flicker frequency exceeds a predetermined number.

Abstract: Method and apparatus are disclosed for detecting and measuring the quantity of particulate matter on a substrate without contacting the sheet or disturbing the particulate matter. Directed, non-visible light energy interacts with particulate matter on the surface of the sheet; and a portion of such incident light energy is redirected at an acute angle that is significantly different from the angle of reflection of such light energy by the surface of the sheet. Infrared energy, particularly that having a wave length of about 940 nanometers, is particularly effective in the detection and measurement of clear epoxy powder; and the portion of such infrared energy effected by the particulate material may be related to the quantity of particulate material on the substrate.

Abstract: A gaseous sample and a reference volume are traversed by electromagnetic iation and the absorption caused by the sample, as given by the difference between the radiation intensities after passage through the sample and the reference volume, is measured and used as a measurement value.By means of radiation of a wavelength in the range between 3.8 and 4.15 .mu.m, the specific mass of particles characterized by broadband absorption--especially graphitic particles--is determined; by means of radiation of a frequency band centered in the wavelength range of 3.35 to 3.5 .mu.m, whose 3 dB bandwidth does not exceed 0.3 .mu.m, the specific total mass of aerosol particles is determined, and by the additional measurement of the resonance absorption at a wavelength in the range of 3.35 to 3.5 .mu.m the percentages of both graphitic and organically soluble particles are determined separately.

Abstract: A passive infrared intrusion detector is configured to resemble an electrical wall outlet. The unit includes a light for visually indicating the direction of its beam of sensitivity, and a lens unit which facilitates directional adjustment of the beam.

Abstract: A train monitoring system for detecting hot boxes, dragging equipment and the like at the rail site, determining the location on the train of a monitored defect and annunciating the defect and location from a digital automated voice generator to the train crew as well as along a telephone line to a central location. Recording of the defect with time and date of same is provided. The system also has provision for self check via an external simulated train.

Abstract: A portable length probe having a length measuring wheel with light transmission holes at equally spaced angular intervals thereon, which wheel is rotatably mounted in an integral one piece nose body having a photo-responsive element and a light-emitting element disposed in aligned facing relation in a common bore formed in the nose body transverse to the wheel. The photo-responsive element is an infrared sensitive photo-transistor and the light emitting element is an infrared light emitting diode (LED), and both are encased in cylindrical opaque cases which fit in generally complementary sliding relation within the bore, the cases each having an optically open end facing one another. Increased accuracy is provided by employing frequency doubler circuitry in conjunction with the wheel, in which the wheel light transmission holes are substantially uniform in angular width and are spaced apart a distance substantially equal to such hole angular width.

Abstract: A fire sensor system that can discriminate between a hydrocarbon fire and the effects of a penetration flash has four channels. A first channel of the system detects electromagnetic radiation in a spectral band of relatively long wavelength and a second channel detects electromagnetic radiation in a spectral band of relatively short wavelength. A third channel compares the relative intensity of the radiation detected by the first two channels and will generate a control signal if the ratio of intensities deviates substantially from unity. This third channel control signal, when generated, will be delayed by a first predetermined period of time, and then will trigger an output signal if the first two channels still detect predetermined levels of radiation. The first predetermined delay period is set to be long enough to allow a substantial amount of the radiation of a flash subside.

Abstract: An Improved Intruder Detection Module is disclosed that incorporates a compact, unique optical system, a detector array, and an electronic system of a combined size and configuration that permits the Module to be shaped to approximate a normal household wall outlet box and its associated face panel. The optical system incorporates removable facet reflectors enabling the system to monitor any of a variety of different fields of view. The detector array includes pyroelectric elements mounted in an adjacent facing relationship to cause radiation passing through one element to immediately pass through the adjacent element, thereby causing intense white light to which the detector elements are not particularly responsive to generate substantially the same electrical signal in both elements. The electronic system may include a unique self-checking feature to regularly insure that the system is properly functioning, thereby avoiding nonresponse to an intruder.

Abstract: A Simplified Intruder Detector is disclosed that incorporates a compact, unique optical system and detector array, including pyroelectric elements mounted in an adjacent, facing relationship. This causes radiation passing through one element to immediately pass through the adjacent element, thereby ensuring that white light, to which the detector elements are not particularly responsive, will generate substantially the same electrical signal in both elements. The electrical system preferably includes a unique power test feature to regularly insure that the system is adequately powered, but only after an intruder has been detected, thereby avoiding nonresponse to an intruder as well as false alarms.

Abstract: A flame detector, in which the generation of a flame is detected by detecting the level of radiant rays at the wavelength characteristic of flame, of infrared rays radiated from the objects generating the flame and in a valley between both of the wavelengths by means of infrared detectors and judging from the comparison of the outputs of the detectors, whether or not there is a valley in the spectrum.The construction of a flame detector according to the present invention can surely detect flame merely by comparing three quantities of radiant rays at three wavelengths without false alarms and accordingly, an element for setting a standard value is not required. This results in a flame detector having a remarkably simple construction.

Abstract: A radiation detector contains a sensor element constituted by a pyroelectrical element, for instance formed of lithium-tantalate, lead-zirconate-titanate, lead-zirconate-iron-niobate or polyvinyldifluoride. Arranged forwardly of the sensor element is a filter combination constituted by a first filter element comprising a germanium or silicon filter having vapor-deposited thereon a narrow band filter having a transmission or throughpass maxima at about 4.3-4.4 .mu.m, and a further filter element formed of sapphire or rutile or a calcium aluminate-, germanate- or a magnesium-fluoride glass. This filter combination has a transmission maxima at the resonance radiation of carbon dioxide at 4.3-4.4 .mu.m, while all other wavelength regions are damped by a factor of more than 1000. Furthermore, there can be provided an additional or auxiliary filter which absorbs radiation in the region of 3.5-4.0 .mu.m transmitted by the narrow band filter in the presence of angular or oblique incidence of such radiation.

Abstract: Electro-optical apparatus for measurement of fat, protein, lactose and solids in milk wherein a milk sample in a test cell is irradiated with reference and measurement beams at differing wavelengths for fat, protein and lactose, and signals are stored indicative of uncorrected concentrations. A scaling and correction circuit includes cross-correction circuitry for compensating the effects on each reading caused by the other constituents. The signals so corrected are then provided in percentage by weight or weight over volume on suitable digital displays. For enhanced accuracy of fat concentration, infrared absorption is measured at both the carbon-hydrogen stretching wavelength (3.48 microns) and the wavelength of absorption at the ester linkages (5.72 microns), and the resulting readings are combined in a predetermined function for obtaining a reading of fat concentration.

Abstract: A thermometry system utilizes the thermally sensitive time dependent emission properties of luminescent materials. In one embodiment the system includes a probe constructed with an optic fiber bundle for conducting light both toward and away from the temperature sensitive luminescent element located at one end of the optic fiber bundle, a source for transient and/or modulated excitation of the temperature sensitive element, and a light responsive detection element located at the output end of the optic fiber bundle for detecting the transient and/or modulated light emissions by the luminescent temperature sensitive element. The emission signal received by the light responsive detector can be analyzed in a well defined manner to determine the temperature of the luminescent element and of any materials in thermal equilibrium with the luminescent material.

Abstract: A moving object sensing processor responsive to slowly varying motions of a human being or other moving object in a zone of interest employs high frequency pulse modulated non-visible radiation generated by a radiation generating source, such as an LED, and detected by a detector sensitive to radiation of a preselected wavelength which generates electrical signals representative of the reflected radiation received from the zone of interest. The detectorsignals are processed to normalize the base level and remove variations due to background level changes, and slowly varying changes in the signals are detected by a bi-polar threshold detector.

Abstract: The present invention concerns a method for remotely surveying the earth's surface. The method comprises the steps of advancing a plurality of electromagnetic scanning devices (3) along a known path at a predetermined height and velocity above the earth's surface, simultaneously scanning a track (4) of predetermined width on the earth's surface with said scanning devices, detecting with the scanning devices electromagnetic radiation received from the earth's crust in the electromagnetic spectrum, each scanning device responding to a different spectral range within the electromagnetic spectrum, and producing a film record (20) from each scanning device corresponding to the intensity of the radiant energy detected by the scanning device within its spectral range.

Abstract: An infrared intrusion detector, utilizing as a sensor element a pyroelectric detector element, accomplishes evaluation of the output signal of the detector element with a charge amplifier, for instance by means of a capacitive feedback coupled operational amplifier, the output signal of which is reset at certain time intervals. The evaluation circuit operates independently of the detector capacitance and therefore enables optimum utilization of the pyroelectrical properties. By virtue of the short-circuit operation and the low ohmic properties of the circuit there is obtained a particularly good non-sensitivity against external disturbances and low noise and increased sensitivity.

Abstract: Photoelectric type detector responds to radiation in a narrow wavelength band characteristic of a fire or explosion, and a slow-response detector, such as a thermopile, is sensitive to radiation in a different narrow wavelength band centered at, for example, 4.4 microns, again characteristic of the same fire or explosion. The electrical outputs of the detectors are fed into a ratio unit which causes an AND gate to produce a fire or explosion indicating output only when the ratio of the output of the thermopile detector to the output of the other detector exceeds a predetermined value.

Abstract: A system for discriminating between radiation produced by a source of fire or explosion to be detected and that produced by a source not to be detected, comprises two radiation detectors 10, 12 respectively responsive to the intensity of radiation in different and spaced apart narrow wavelength bands. A rate of rise unit 22 and a threshold unit 24 responsive to detector 12 produce signals of a first binary type when the rate of, and the value of, the radiation intensity exceed predetermined values. A ratio unit 16 measures the ratio of the intensities of the radiation received by the two detectors and produces a signal of the opposite binary type when the ratio indicates that the source of radiation is a fire or explosion to which the system is not to respond. An AND gate 36 produces a fire and explosion indicating output only when the signals of the first type exist in the absence of the signal of the opposite type.

Abstract: A pyroelectric pellet made of a Z cut plane of lithium tantalate, for example, is fixed onto an electrically conductive supporting base made of copper, for example, by means of an adhesive agent layer. One embodiment of the adhesive agent layer interposed between the pyroelectric pellet and the electrically conductive supporting base comprises a mixture of an electrically conductive adhesive agent, such as a silver paste, admixed with heat insulating grains made of glass, ceramic, or the like, whereby thermal dissipation from the pyroelectric pellet to the electrically conductive supporting base is decreased. Another embodiment of the adhesive agent layer comprises an electrically conductive adhesive agent layer in which is embedded a thin sheet made of synthetic resin having apertures. The electrically conductive adhesive agent extends through the apertures of the sheet so as to fix the pyroelectric pellet to the electrically conductive supporting base.

Abstract: The improved intruder detection system of the present invention, because of its sensor, optical, and electronic systems, is uniquely capable of responding only to radiation from an intruder to signal an alarm. To achieve this, the sensor and optical systems are designed and cooperate to optically reject and balance-out extraneous, nonintruder-related radiation. In addition, the electronic system detects and rejects nonintruder-related inputs by recognizing certain uniquely intruder-related characteristics of the sensor signals, and to only signal an alarm in response to inputs evidencing such characteristics. Preferably the system is designed to reliably sense the presence of an intruder in multiple zones, to be economical to manufacture, easy to install, to be battery-powered and of a long life.

Abstract: A hand-held instrument is provided to compare information from selected infrared and visible bands in the 0.4 to 2.5 micrometer range, to perform ratioing via a dividing circuit (17) and to directly read out, via a display system (18), ratio values in a continuous digital display. The dual-beam, ratioing radiometer contains two optical trains (10, 12), each having two repeater lenses (L1a, L1b and L2a, L2b) and a cooled lead sulfide detector (D1, D2). One of the trains (10) is pivotal to facilitate measurements at distances ranging from about 1 meter to infinity. The optical trains are intersected by a set of two coaxially-mounted filter wheels (F1, F2), each containing up to five interference filters and slits to pass radiation filtered by the other. Filters with band passes as narrow as 0.01 micrometer are used in the region 0.4 to 2.5 micrometers. The total time for a calibration and measurement is only a few seconds. It is known from previous field studies using prior art devices, that materials, e.g.

Abstract: The improved intruder detection system of the present invention, because of its sensor, optical, and electronic systems, is uniquely capable of responding only to radiation from an intruder to signal an alarm. To achieve this, the sensor and optical systems are designed and cooperate to optically reject and balance-out extraneous, nonintruder-related radiation. In addition, the electronic system detects and rejects nonintruder-related inputs by recognizing certain uniquely intruder-related characteristics of the sensor signals, and to only signal an alarm in response to inputs evidencing such characteristics. Preferably the system is designed to reliably sense the presence of an intruder in multiple zones, to be economical to manufacture, easy to install, to be battery-powered and of a long life.

Abstract: Sand containing bitumen and like materials containing organic matter is analyzed quantitatively for its hydrocarbon content by use of a remote infrared sensor. In a preferred embodiment the bitumen is on a conveyor to further processing and if found unacceptable for processing by the method of the invention, the sand is automatically diverted. The invention also embodies the apparatus used for the analysis.

Abstract: A device for optically displaying thermal image scenes, comprising pneumatic infrared sensors, for example, temperature-sensitive gas cells. A mosaic of thermal IR sensors, which is arranged on an infrared-transparent plate and which picks up the thermal image scene, is arranged in front of a reference plate whose inclination can be adjusted and which is irradiated by optical light. The interference patterns produced are picked up by an optical system. Thermal drift is suppressed by providing the IR sensors in a hermetically sealed chamber.

Abstract: Disclosed is a fire and explosion detection system wherein long wavelength radiant energy responsive signals are processed in one channel and compared to short wavelength radiant energy responsive signals which are processed in a second channel. At least one of the channels is responsive to a wavelength where at least one of the combustion products of the fire or explosion exhibits a strong absorption band in the atmosphere. When the signals from the two channels are coincident in response to a fire or explosion of a predetermined threshold magnitude, an output fire suppression signal is generated.

Abstract: A radiation absorbing cone (34) affixed to an infrared pyrometer (31) has a pair of lateral apertures (36--36) therein through which a continuously moving heated wire (11) passes. The cone (34) blocks stray ambient radiation while substantially eliminating any reflected radiation from the wire (11) from impinging on the pyrometer (31) to provide an accurate and repeatable measurement of the wire temperature.

Abstract: A method and apparatus for detecting optical radiation by optically monitoring temperature changes in a microvolume caused by absorption of optical radiation to be detected. More specifically, a thermal lens-forming material is provided which has first and second opposite, substantially parallel surfaces. A reflective coating is formed on the first surface, and a radiation-absorbing coating is formed on the reflective coating. Chopped, incoming optical radiation to be detected is directed to irradiate a small portion of the radiation-absorbing coating. Heat generated in this small area is conducted to the lens-forming material through the reflective coating, thereby raising the temperature of a small portion of the lens-forming material and causing a thermal lens to be formed therein. The thus-formed thermal lens is optically detected by irradiating the thermal lens by a collimated light beam.

Abstract: An infrared heat-image camera is aimed at a hot surface not perpendicular thereto but instead in a direction almost parallel to the surface, presenting to the camera a heat image of the surface not cartesian but instead highly distorted in accordance with the laws of optical perspective. The camera's output data is correspondingly non-cartesian and distorted with respect to organization and content, but the data is applied to a computer which transforms it to cartesian organization and corrects content, and then a corrected cartesian display is generated, simulating the heat image which would be presented to a perpendicularly aimed camera. Alternatively, the camera's scanning mechanisms are programmed to follow a non-cartesian scanning schedule, the geometry of which itself causes the camera output data to have the cartesian organization of a perpendicularly aimed camera.

Abstract: Method and apparatus for monitoring particulate mass concentration of emissions, such as fly ash, from a stationary source are disclosed which employ a single-wavelength infrared transmissometer. Emissions from a source, such as a fossil fueled power plant, generally contain particles of known material of a wide range of sizes. Often the particle size distribution varies during emission. In accordance with the present invention a single-wavelength transmissometer is employed which operates at a wavelength at which the extinction-to-mass concentration ratio as a function of particle size is substantially constant. Consequently, the transmissometer output provides a measure of the mass concentration of particulate material emitted from the source independent of the size of the particles. Logarithmic amplification of the transmissometer detector output provides a direct measure of the mass concentration.