Abstract: A smoke chamber for determining the amount of visible smoke emitted by a foundry core/mold resin system is composed of an elongate chamber having a proximal end, a distal end, and sides. The chamber is fitted with air inlet at its proximal end, a smoke outlet at its distal end, and a sample station disposed between the air inlet and the smoke outlet. The sample station includes a sample holder and furnace for heating a sample placed in the sample holder. The chamber also includes a light assembly disposed along one side of the chamber from the sample station to the smoke outlet. A light detection assembly is disposed on a chamber side opposite the light assembly for detecting light emitted from the light assembly. The chamber also includes fan for drawing smoke from a heated sample placed in the sample holder to the smoke outlet. The corresponding method for determining the amount of visible smoke emitted by a foundry core/mold resin system includes placing a sample in the sample holder.

Abstract: This invention describes method and apparatus for protecting optical sensors in harsh industrial environments, particularly welding and machining. In a preferred embodiment, a sacrificial window is utilized which is replaced as needed. Numerous design features of such windows are disclosed. Other embodiments include protective baffles and other features.

Abstract: A vehicle gas analyzing system for testing gas content in exhaust emitted from a vehicle is disclosed. The vehicle gas analyzing system is of a size and weight to be held in a user's hands. The system includes a housing having outer dimensions no greater than about 12".times.8".times.3", and has an inlet receiving exhaust emitted from the vehicle. A sensor assembly is disposed in the housing, receives the exhaust emitted from the vehicle through the inlet, and determines the content of a plurality of different gases in the exhaust. A user interface is disposed on an outside surface of the housing, allowing a user to input instructions to the system and to perceive output from the system.

Abstract: An optical cavity resonator device is provided for conducting sensitive murement of optical absorption by matter in any state with diffraction-limited spatial resolution through utilization of total internal reflection within a high-Q (high quality, low loss) optical cavity. Intracavity total reflection generates an evanescent wave that decays exponentially in space at a point external to the cavity, thereby providing a localized region where absorbing materials can be sensitively probed through alteration of the Q-factor of the otherwise isolated cavity. When a laser pulse is injected into the cavity and passes through the evanescent state, an amplitude loss resulting from absorption is incurred that reduces the lifetime of the pulse in the cavity. By monitoring the decay of the injected pulse, the absorption coefficient of manner within the evanescent wave region is accurately obtained from the decay time measurement.

Abstract: On-board ILS ethyl alcohol sensors based on intracavity laser spectroscopy (ILS) are provided for detecting the presence of ethyl alcohol vapors in a vehicle. The sensor comprises: (a) a laser comprising a gain medium having two opposed facets within a laser resonator and functioning as an intracavity spectroscopic device having a first end and a second end, the first end operatively associated with a partially reflecting (i.e., partially transmitting) surface; (b) a reflective or dispersive optical element (e.g.

Abstract: The present invention relates to an analyzer for determining the concentration of substances, such as chemicals, present in a fluid medium, such as gas, vapor or liquid, using holographic optics. The analyzer of the present invention is based on the infra red absorbance of the gas, vapor or liquid to be measured, where the optical functions of an infra red absorbance gas analyzer are performed by holographic functional representations of the required optical components.

Abstract: An apparatus is disclosed for continuously sampling, at a point downstream of the air cleaner, the normally clean air entering an air induction system of a diesel engine to produce a signal indicating a leakage malfunction condition in the air induction system by measuring dust/particulate matter. The disclosed apparatus includes an arrangement in the form of a sample collector assembly for obtaining a representative sample of leakage particulates within the diesel engine intake system, a measurement assembly for the quantification of the dust/particulates by optical methods, a signal conditioning assembly (200), a processor (300), and a remote annunciation assembly (400).

Abstract: This invention describes a method and apparatus for protecting optical sensors in harsh industrial environments, particularly welding and machining. In a preferred embodiment, a sacrificial window is utilized which is replaced as needed. Numerous design features of such windows are disclosed. Other embodiments include protective baffles and other features.

Abstract: A novel method for calibration of a spectroscopic sensor is provided. In the method, a spectroscopic system is provided. The system includes a measurement cell having one or more walls which at least partially enclose a sample region. The cell further includes a light entry port and a light exit port. The light entry port and the light exit port can be the same port or separate ports. Each of the ports contains a light transmissive window through which a light beam passes along an internal light path inside the measurement cell. The system further has an optical chamber which contains a light source for generating the light beam which passes through the light entry port into the cell, and a detector for measuring the light beam exiting the cell through the light exit port. The light beam passes along an external light path inside the optical chamber. In addition, a gas inlet is connected to the optical chamber. A calibration gas stream is introduced into the optical chamber.

Abstract: An improved method of monitoring particulates in stacks or ducts utilizes transmissometer/particulate monitor of the type which has an optical assembly containing a solid state light source of visible light such as a light-emitting diode or a solid-state laser. The light source emits a collimated beam that is split, part of which is focused onto a reference detector that monitors the intensity of the light source, while the other part is directed to a beam-steering apparatus that causes the beam to accurately pass through a gaseous sample to a desired location such as a retro-reflector. A position-sensing detector is used in a closed-loop manner to control the beam-steering apparatus. The ratio of the total energy of the detected light beam, relative to the reference detector output, is used to determine the opacity of the gaseous sample for the purpose of providing a basis for correlation to particulate loading of that portion of the particulates that are of a size comparable to the wavelength of light.

Abstract: A non-contact optical backscatter insertion probe includes an outer chamber, an electromagnetic energy source positioned within the outer chamber for emitting photons towards a medium to be analyzed, and an inner chamber positioned within the outer chamber. The inner chamber has a reflective outer surface to prevent photons emitted by the electromagnetic energy source in the outer chamber from entering the inner chamber. The probe also includes a sensor positioned within the inner chamber for receiving backscattered photons from the medium. The inner chamber provides the backscattered photons emitted from the medium to the sensor. A processor receives and processes signals output by the sensor.

Abstract: Contaminants in corrosive gases are detected optically at concentrations below 1 part-per-million (ppm) and extending to a level below 1 part-per-billion (ppb) by using intracavity laser spectroscopy (ILS) techniques. A laser, the ILS laser, is employed as a detector. The ILS laser comprises a gain medium contained in a laser cavity. A gas sample containing gaseous contaminant species is contained within a gas sample cell which is placed inside the laser cavity and on one side of the gain medium. Accordingly, the corrosive gas is prevented from reacting with the components of the ILS laser. The output signal from the ILS laser is detected and analyzed to identify the gaseous species (via its spectral signature). The concentration of the gaseous species can be determined from the spectral signature as well.

Abstract: An apparatus for measuring light penetrability of liquids, including: a water-tight, heat, compression and chemical resistant casing, a light source mounted inside the casing and controlled to alternately, emit light of different wavelengths, a controller mounted inside the casing for detecting light and converting detected light into electrical signals, and a light guide mounted inside the casing for guiding light from the light source to the controller through a liquid to be tested.

Abstract: An LD light-emitting circuit 2 comprises an analog multiplexer MP having a plurality of switches, and resistors R7, R8, R9 and R10 connected to these switches. When the temperature is not higher than a normal temperature, the resistor R7 is connected so that the amount of light emitted from the LD 1 is maintained constant. As the temperature rises, however, the resistor R8, R9 or R10 having increasing resistance is connected in response to a signal from a control circuit, in order to decrease the driving current that flows into the LD 1. This enables the LD 1 to suppress its own heating and to lengthen its life.

Abstract: A stack gas monitor system has an optimized gas flow portion which is permanently installed in a fossil fuel burning facility, and to which a spectrophotometric portion can be readily coupled for real-time determination in the system of a concentration of a first gas having a characteristic absorption spectrum and which is selectably introducible as a measured amount into a stack gas stream. A sample of the stack gas stream is flowing through the gas flow portion, with at least one gas of the sample stream having an absorption spectrum extending within an ultraviolet range of wavelengths of radiation and having absorbance values within this range which are higher than absorbance values of the first gas. The system can be purged and can be calibrated with the first gas. Stack gas blank data are obtained in the absence of the first gas. Composite gas data are provided upon introduction of the first gas into the stack gas.

Abstract: A method and apparatus using either two or three input laser beams in a nonlinear degenerate four-wave mixing arrangement for ultrasensative analytical measurements of an analyte. In accordance with a first embodiment of the present invention, a two input beam F-D4WM arrangement is used to generate two phase conjugate signal beams. The input beams are narrowly focused to intersect within a very small volume of an analyte. The analyte may be in any physical state (e.g., liquid, solid, or gas). The intensity of the signal beam is used to detect trace concentrations of particular substances. The beam spot of each of the input beams can be focused to less than 34 .mu.m, thus allowing the present invention to directly focus the input beams within a capillary tube of a HPCE or a column of a HPLC system. In accordance with the second embodiment of the present invention, the input laser beams of a F-D4WM method are directed to points on a lens by immobilized fiber optic cables.

Abstract: An apparatus for detection and measurement of trace species in a sample gas. A ring down cavity cell is filled with the sample gas. A continuous wave laser emits radiation, which is directed from the continuous wave laser to the ring down cavity cell where it resonates. A photodetector measures radiation levels resonated by the ring down cavity cell and produces a corresponding signal. The decay rate of the ring down cavity cell is calculated from the signal produced by the photodetector and is used to determine the level of trace species in the sample gas.

Abstract: A separate type photoelectric smoke sensor having a light emitting section for emitting a light beam to a reflecting plate disposed at a certain distance from the light emitting section, a light receiving section for receiving reflected light from the reflecting plate, and a judgement section for outputting a sense signal if a received light output from the light receiving section is smaller than a threshold value previously set.

Abstract: A process environment monitoring system collects and tests air samples from a number of different sample locations. Each sample is drawn into a sample test chamber into which a beam of infrared light is directed from an infrared source. The beam is reflected off mirrors in the test chamber a number of times before it exits and is directed to an infrared detector. The detector identifies absorption peaks in the spectrum of the infrared beam to determine the presence of certain gases of interest in the test chamber. A host computer is provided to function in conjunction with a valve controller to make up a data processing unit. The data processing unit services a number of tasks to make the process environment monitor a fully integrated system. The system controls employee identification, alarm triggering, and automated system control, as well as a number of other functions.

Abstract: A self-cleaning smoke-monitoring system that is used in measuring opacity of exhaust from an internal combustion engine. The invention includes a pair of air passages that supply a flow of filtered air over the optic elements of the smoke-monitoring system. The flow of particulate-free air is the result of a venturi effect created in the exhaust flow such that ambient air is continuously drawn in through the air ducts.

Abstract: Two optical windows serve for the passage of a light beam through a treatment chamber in which a product is disposed whose dimensions are to be detected. Between the treatment chamber and each one of the optical windows there is disposed a rotary valve, which permits the separation of the optical window from the treatment chamber. Thus it is possible to prevent a medium that adversely influences the optical windows in the treatment chamber from gaining access to the interior face of the windows if protection of the windows has priority over a measurement. It is thus possible to considerably extend the service life of the windows.

Abstract: A system (10) for detecting nitric oxide (NO) within an exhaust plume (14) includes a source (18) for generating an optical beam (20) and for directing (22, 24) the optical beam through the exhaust plume, the optical beam having wavelengths within a predetermined band of wavelengths within the infrared (IR) radiation spectrum. The system includes a sensor (32)/filter (30) assembly having a first channel for determining a measured NO transmission value for a first predetermined band of wavelengths; a second channel for determining a measured water transmission value for a second predetermined band of wavelengths; a third channel for determining a measured reference transmission value for a third predetermined band of wavelengths selected so as not to be significantly absorbed by the exhaust plume; and a fourth channel for determining a measured combustion by-product transmission value for a fourth predetermined band of wavelengths.

Abstract: In accordance with this invention, a misalignment detector apparatus is provided for a transmissometer with an underfilled reflector. The transmissometer has a transceiver that projects a collimated beam of light of small diameter across a smokestack to a circular reflector of substantially greater diameter than the collimated beam of light so that the reflector is underfilled. The reflector includes apparatus for sensing the position of the collimated beam of light with respect to the center of the reflector and its position on the reflector when it is not on center which allows operator notification of when the beam is on the reflector and when the beam is off the reflector thereby requiring maintenance/realignment.

Abstract: An exhaust gas particle sensor has an inlet tube and a sensing region having different cross sections and linked by a transition region including a number of baffles arranged so that the time taken for gas to travel from the inlet tube to the sensing region is substantially independent of the position of the gas across the inlet tube. The sensor operates by measuring the opacity of the exhaust gas using a light beam which passes in and out of the sensing region through windows, the exhaust gas being prevented from impinging on each window by a double air curtain.

Abstract: A smoke opacity detector includes a sample chamber; a sample heating block in the sample chamber for heating a sample; a first temperature control for controlling the temperature of the sample heating block to a desired temperature; a measurement stack positioned above the sample heating block for receiving smoke resulting from heating of the sample by the sample heating block; a laser light source for projecting a light beam through the smoke in the measurement stack; a photodetector for detecting the amount of light from the laser light source that passes through the smoke in the measurement stack; a microprocessor for determining the amount of smoke resulting from heating of the sample, in response to the light detected by the photodetector; and a device for selectively eliminating conditions of water vapor in the determination of the amount of smoke by the microprocessor, the device for selectively eliminating including a heating device for heating the measurement stack and a second temperature control fo

Abstract: A smoke meter is particularly adapted to meter the smoke content of vehicle exhaust gases. The meter includes a measuring tube with a light at one end and a light detector at the other end, the amount of light detected corresponding to the smoke content. The optical surfaces are kept clean by inducing a flow of clean air across the surfaces using an air supply which also induces flow of gas into the measuring tube.

Abstract: A device is proposed for measuring the composition of fluids, in particular of constituents of exhaust gases from internal combustion engines, in which a light ray (32, 31) is used to irradiate the exhaust gas to be measured over the length of a measuring section (29) and is weakened or changed more or less, depending on the content of constituents. The light signal being received is advantageously registered by a measured length light receiver (18) which is shielded light-tight against the light emitting light source (14) and is evaluated in relation to the original light emission, in an evaluation circuit (26). In this simple way, accurate information is obtained of the exhaust gas clouding and of the loading of a fluid or gas with constituents which are optically active.

Abstract: An apparatus and method for determining the propensity of a polymer to emit smoke by measuring the smoke emitted when the polymer is melted and extruded. The polymer is heated to a molten state and extruded under controlled time conditions into a receptacle from which gaseous samples can be collected, then the gaseous samples from the receptacle are analyzed for smoke content to determine the propensity of the polymer to emit smoke.

Abstract: The invention is directed to a mirror arrangement for a beam path in a multiple-reflection cell for measuring the absorption of light in a measuring gas. In the measuring arrangement, an entrance aperture is imaged on an exit aperture via an entrance aperture mirror, a field mirror and an exit aperture mirror. This arrangement is improved in that the astigmatism of the imaging error is considerably reduced. For this purpose, the form of the aperture mirrors is approximately defined by an ellipsoid wherein the focal point spacing is approximately equal to half the distance between the entrance aperture and the exit aperture.

Abstract: A method for operating an optical smoke detector, wherein for smoke detecting purposes at least one light sensitive receiver within a detection chamber measures the useful scattered radiation which emanates from a volume unit within said chamber which is located in the intersecting area of the collimated field of view of said receiver and of the collimated beam of a light source within said chamber, said receiver sensing the scattered radiation caused by a contamination of said chamber or a second light sensitive receiver detecting the radiation reflected from a surface unit of said chamber, respectively, whereby measuring the reflexion radiation emanating from an illuminated surface unit within said chamber.

Abstract: An apparatus and method for reliably generating simulations of actual dust suspension conditions and measuring the associated density of suspended dust. The dust monitor is constructed to permit generation of dust suspensions by achieving various pre-selected motions for the test material, such as a rolling motion or swirling motion relative to the forward direction of travel of the test material. The apparatus and method permit prediction and control of the propensity to form dust suspensions during actual operating situations in the field.

Abstract: Methods and apparatus for continuously and instantaneously measuring sidestream smoke are provided. A hood assembly is provided to fit over the ports of a conventional smoking machine. Sidestream smoke produced by test cigarettes is continuously drawn through the hood by an exhaust system. A laser beam is passed through the smoke one or more times before the beam is sensed by a photodiode detector. An electrical signal from the detector, representing the light transmission, is received by a strip recorder or computer system. The transmission measurements are used to calculate the extinction coefficient of the smoke for comparison purposes.

Abstract: Method and apparatus for sampling the gaseous medium of a zone or area to determine the concentration, or changes in concentration, of submicron particles suspended in the gaseous medium of that area or zone using an elongated cloud chamber. A light source and a phototransistor are disposed in the cloud chamber and spaced apart so as to be electronically responsive to varying levels of light. A microprocessor is connected to a programmable memory EPROM and has pre-programmed data instructions on particle concentration levels. The EPROM sequences the microprocessor to operate the valves that sequentially sample the gaseous medium in the cloud chamber, and opens the exhaust valve in the cloud chamber to create a condition of reduced gas pressure therein. The sample of gaseous medium containing submicron particles then precipitates or condenses a portion of the cloud in the chamber in proportion to the concentration of the particles.

Abstract: A focused beam of light from a light source is directed into a closed smoke chamber, having inlets for admitting smoke particles, toward a reflector which reflects and refocuses the beam back into the light source, the direct beam and the reflected beam passing through a test zone within the chamber. In the event that smoke particles enter the test zone, the direct and reflected beams strike and bounce off of those particles to produce scattered radiation that will be picked up and detected by a light responsive sensor to generate an alarm signal. By closely controlling, rather than baffling the light, optimum operation is obtained, efficiency is enhanced and false alarms are minimized.

Abstract: An across-the-stack gas analyzing spectrometer has a radiation source assembly including a cylindrical tube 22 having, in succession from its outer end toward the stack end a radiation emission assembly 28, a first lens assembly 30, and an AOTF assembly, all in optically aligned arrangement because of the circular perimeter of the elements in the circular tube, the arrangement also including a projecting second lens nozzle 98 received in an air window assembly 104 which forms a venturi with the second lens, the air window having a ball joint arrangement 120 for easy alignment of the directed beam, and also including a small diameter air window tube 142 through which clean air is directed into the stack through a larger diameter stack opening.

Abstract: In connection with an optical indication and function monitoring unit for vacuum cleaners comprising optical dust detection means in the form of a luminous diode and a phototransistor provided adjacent the suction duct, and optical indication means for the user, it is proposed to provide, in addition to first delay means for the dust detection means, second delay means having a longer time constant and designed in such a manner that a third flashing luminous diode, which also lights up when the supply battery is nearly run down, is triggered when the dust indication does not operate for an extended period.

Abstract: A light-scattering-type smoke detector having a projecting element and a light receiving element surrounded by a labyrinth is disclosed wherein the labyrinth comprises an array of a plurality of light shielding columns arranged in a circle each having a substantially J-shaped cross section, and the head portion of each column is inclined relative to the bisector of an angle formed between the lines connecting a first reflecting point with the projecting and light receiving elements, the light shielding columns having darkly colored light reflective surfaces.

Abstract: An optical dust detector assembly includes an air duct member having an introductory portion and a base portion for permitting a flow of air passing therethrough, the duct member having a pair of radial holes formed in its peripheral wall, a pair of cylindrical casings secured to the peripheral wall of the duct member at both sides thereof and having respective opening ends communicating with the interior of the duct member through the respective radial holes thereof, a light emission element arranged within one of the casings to emit a light beam and pass it through the radial holes toward the other casing, and a light receiving element arranged within the other casing to receive the light beam emitted from the light emission element and passed through the radial holes.

Abstract: A device for measuring the optical turbidity, i.e., the soot components in discharge gases of diesel engines, which is relatively simply constructed, operates safely and enables a simple handling even with differently structured measuring devices. This result is achieved in that a controller for controlling the light density of the measuring light beam is optically coupled with a light source. A sample and hold circuit is provided with the values of a measuring detector and the control detector fed to a sample and hold circuit in a time multiplex manner with the measuring values processed in a computer unit. Control values are fed to the light source by means of a control loop. In addition, the computer unit is capable of storing a plurality of measuring values or turbidity values and average value of the stored peak values, whereby the peak values are determined by a dynamic measuring of a defined number of measuring cycles.

Abstract: A dust detector ring assembly for detecting extremely small quantities of particulate contamination in air being taken into the carburetor of an engine is disclosed. The assembly includes a series of infrared light emitting diodes alternately interposed with a like series of infrared light detecting diodes and arranged in a circle around an interior surface portion of a frame defining a passageway of circular cross-section therethrough. A light beam generated by each of the emitters is directed against a different one of the detectors so that the light beams intersect one another at a common point in the passageway. The sensitivity of the assembly is thus greatest at the common point of intersection of the light beams and decreases proportionally moving away from the intersection point toward the defining surface of the passageway. A flexible circuit board is formed in a circle and is connected to the emitters and detectors. A flat circuit board is connected to the circular circuit board.

Abstract: A multiple pass optical system comprising a reflecting objective placed across the path of a radiant flux emitted by an illuminator; the objective being mounted pivotally around its own axis. Further, the radiant flux its incident upon a compound collective comprised of two different-curvature mirrors arranged at right angles to each other.From the lens of the radiant flux, the flux is directed again to the reflecting lens to be reflected therefrom and upon passing the final cycle in the system, it emerges.

Abstract: An optical detector assembly comprises a casing formed therein with a through bore having front and rear openings and a pair of opposite cavities located at both sides of the through bore, an air duct member disposed within the through bore to permit the flow of air passing therethrough, the duct member being formed at its peripheral wall with a pair of radial holes opening toward the cavities respectively, a light emission element arranged within one of the cavities to emit a luminous ray and pass it through the radial holes of the duct member toward the other cavity, a light receiving element arranged within the other cavity to receive the luminous ray emitted from the light emission element and passed through the radial holes, and an air induction assembly coupled over the front opening of the through bore for preventing entry of alien particles such as dirt, water, snow and the like into the duct member.

Abstract: A photoelectric smoke detector operating on a scattered light principle. The photosensor is connected at the input of an operational amplifier, such amplifier functioning as a threshold detector, saturation pulse amplifier and fixed pulse width compensator. Another feature of the invention resides in the provision of a special RC network connected from the output of a first transistor of a flasher section or subcircuit, which provides pulse power to the light source, to the input of a second transistor in such flasher circuit. As a consequence of this arrangement, when the LED serving as the light source tends to age, with a corresponding increase in its impedance, an appropriate signal is fed back from the aforenoted output of the first transistor to the input of the second, thereby to increase the pulse width of the output signal through the LED such that it is no longer, thereby compensating for the fact that it is no longer as bright.

Abstract: The method and apparatus permit analyses, by optical means, of properties of gaseous suspensions of particles, by measuring radiation that is emitted, transmitted or scattered by the particles. Determinations of composition, size, temperature and spectral emittance can be performed either in-situ or by sampling, and Fourier-transform infrared spectrometric techniques are most effectively used. Apparatus specifically adapted for performing radiation scattering analyses, and for collecting radiation from different sources, are provided.

Abstract: An optical gas densitometer is provided comprising a conical filter portion having a front and rear end disposed to the inside of a cell portion and formed into a conical shape, which has a reflection mirror disposed to the inside of the front end thereof, windows disposed at the rear end thereof and in which the angle between an incident optical beam and an exiting optical beam is predetermined. Plate means at the front end of the filter and formed in a space between the inside of the cell portion and the outside of the conical filter portion, divides the space into a gas feed channel below the plate means and a gas exhaust channel above the plate means. An opening channel is disposed between the gas feed channel and the gas exhaust channel towards the rear end of the filter. A partition plate connected to the plate means at the front end of the filter, divides a gas sampling tube into first and second channels which correspond to the feed channel and exhausting channel, respectively.

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

Abstract: In the infrared gas analyzers described in the specification, infrared radiation is transmitted through a measuring cell to an infrared detector. The measuring cell has an external case and a tubular filter to remove particulate material from the gas being analyzed immediately before it is intercepted by the infrared radiation.

Abstract: A system for detection of smoke by measuring changes in the contrast of a multi-contrast target disposed remotely from a photoelectric sensor. The obscuration of the detection path causes a reduction in the contrast of the sensed target, and a change of predetermined magnitude is employed to trigger an alarm. The target has one or more relatively darker and one or more relatively lighter areas which are viewed by the sensor. The sensor can be composed of a plurality of photosensors each viewing a respective area of the target. Or, the sensor can be a single scanning sensor such as a video camera. Only a single line or segment of a line of the video frame pattern need be employed to monitor the target. The video camera can be employed on a shared basis for providing smoke monitoring and detection, together with other functions, such as intrusion detection, access control, or visual surveillance of an area.

Abstract: A gas measuring device has a source capable of emitting a beam of radiation aligned to impinge a detector. A housing means encloses the beam. The housing means has a plurality of apertures permitting the gas to enter the housing means, to intercept the beam, and to exit from the housing means. The device further comprises means to control the amount of thermal radiation reaching the detector.

Abstract: An optical analyzer (10) wherein a sample (19) of particulate matter, and particularly of organic matter, which has been collected on a quartz fiber filter (20) is placed in a combustion tube (11), and light from a light source (14) is passed through the sample (19). The temperature of the sample (19) is raised at a controlled rate and in a controlled atmosphere. The magnitude of the transmission of light through the sample (19) is detected (18) as the temperature is raised. A data processor (23), differentiator (28) and a two pen recorder (24) provide a chart of the optical transmission versus temperature and the rate of change of optical transmission versus temperature signatures (T and D) of the sample (19). These signatures provide information as to physical and chemical processes and a variety of quantitative and qualitative information about the sample (19).