Abstract: A scattering cell can contain a sample whose scattering properties upon irradiation are measurable by a detector. The cell includes a central body having an input and output side spanned by a sample cavity. The cell also has an input window bordering the sample cavity on the input side. Also included is a prismatic output window bordering the sample cavity on the output side. This output window is operable to refract its incident radiation and vary the angle between its incident and transmitted radiation as a function of its angle of incidence.

Abstract: An apparatus and process are described for the characterization and/or identification of individual microparticles based upon the measurement of certain optical observables produced as each particle passes through a beam of light, or other electromagnetic radiation. A fine beam of, preferably, monochromatic linearly polarized light passes through a spherical array of detectors, or fiber optics means to transmit incident light to a set of detector means, and a stream of particles intersects the beam at the center of the spherical array. Selected observables calculated from the detected scattered radiation are then used to recall specific maps, from a computer memory means, one for each observable. The common overlap region of said maps yields characterizing or identifying particle physical parameters such as size, mean refractive index, and shape. A method for rapidly discriminating non-spherically symmetric particles is also disclosed.

Abstract: A process and apparatus is disclosed for characterizing an ensemble of microparticles and monitoring their response to environmental factors such as chemically and biologically active agents. The apparatus permits the very accurate measurement of light or radiation intensity scattered by the microparticles at two well-defined scattering angles with respect to the direction of the incident beam. This is achieved by measuring the scattered radiation at two sets of scattering angles each subtending the two defined angles, processing the detected intensities with a computer means to remove spurious data arising from artifacts in the scattering ensemble, and then functionally averaging the so-processed intensities of each set to yield a mean value for the scattered intensity at each of the two defined angles. Monitoring these two values before and after the addition of an environmental factor permits the calculation of a quantitative ensemble response to said environment.

Abstract: An apparatus and method for determining the size and velocity of particles, droplets, bubbles, or the like employing laser light scattering is disclosed. A laser generation means is provided for generating a pair of coherent laser beams. These beams are directed along an axis and are caused to cross the axis at an angle to establish a sample volume. A collection means for sensing the scattering caused by particles, droplets, bubbles or the like within the sample volume is provided. The collected scattered signals are directed onto photo-detectors which are coupled to a signal phase determining means for determining the phase of the scattered signals as the particle, droplet, bubble or the like passes through the sample volume. Sizing means are coupled to the signal phase determining means for determining the size of the particle, droplet, bubble or the like from phase changes and the scattered signal.

Abstract: In an apparatus in which particles which may include biological cells are passed through an optical sensing zone to measure their spatial radiant energy distribution for the purpose of identifying and/or characterizing the particles or cells, a structure and method are provided for increasing the usefulness of a geometric configuration of photovoltaic detectors such as a known assembly of generally concentric rings of such detectors usually including some wedge-shaped detectors. These are provided in a generally planar form and the invention provides structure which captures radiant energy in a flow cell of a particular type before projecting the energy to the detector. In particular an ellipsoid, paraboloid, hyperboloid or similar reflector which is symmetrical about its optical axis is utilized first to capture the radiant energy on angles which could include most forward and/or backward angles and all azimuthal angles and then deviating the same to the detector assembly mentioned.

Abstract: An apparatus and method for determining the percentage of solid particles in a suspension (consistency) is provided. A source of diffused radiant energy is provided which energy is directed toward a suspension to be measured. The portion of the energy which is forward-scattered by the suspension is detected and a first signal indicative of the magnitude of the forward-scattered energy is produced. The portion of energy which is back-scattered by the suspension is detected and a second signal indicative of the magnitude of back-scattered energy is produced. The first and second signals are combined at a predetermined ratio to produce a feedback signal used to control the intensity of energy emitted from the radiant energy source. The intensity of energy emitted from the source is a function of the forward-scattered and back-scattered energy and is directly proportional to the consistency of the suspension being measured.

Abstract: A steam wetness measuring apparatus comprises a light source, a part defining a measuring space when the apparatus is inserted into a wet steam flow, an optical fiber bundle for transmitting the incident light beam from the light source to the measuring space, and optical fiber bundles for transmitting to a photo-electric converter element a plurality of scattered light beams of different scattering angles obtained by radiation of the incident light beam on the measuring space. The fact that the intensity of the scattered light beam changes with the wavelength of the incident light or changes with the scattering angle of the scattered light beam, in accordance with the particle size distribution of water droplets in the wet steam is used to determine the particles size distribution. The steam wetness is determined from the particles size distribution and the physical properties of the wet steam flow.

Abstract: A method of determining the size of spherical particles, comprising the operations of illuminating with a beam of circularly polarized light particles the size of which is to be determined, detecting light backscattered by the particles, measuring the angular intensity distribution of the backscattered light and deriving therefrom an indication of the size of the particles.Various forms of apparatus for carrying out the method also are described.

Abstract: A method for deriving a quantitative measure of a beverage which will correlate to the subjective sensory stimuli response of beverage consumers. The method comprises illuminating an aliquot or a dilution thereof with a beam of monochromatic light, measuring the light scattering pattern produced, comparing this pattern to that of a reference pattern, and using the difference between the two patterns as the quantitative measure. A variation of the method is disclosed wherein a number of measurements at a selected set of angles over a period of time are measured and, at each selected angle, the intensity is measured several times. In this method, the average of the intensities so detected at each selected angle is determined, and the numerical set of the fluctuation of each detected value from the average is used to characterize the beverage.

Abstract: A sensor employs a laser to obtain a collimated light beam for transmission across the gas effluent of a catalytic cracking process. Particulate matter entrained in the gas flow forward scatters light energy to a collecting aperture which, in turn focuses the scattered light on a first photodetector. A second photodetector receives directly transmitted light energy. A ratio between the output signals of the two photodetectors is derived and presented to a threshold level detector. If the magnitude of the scatter exceeds a predetermined level it is concluded that a catalyst load dump has occurred. The optical system is carefully selected to ensure that only light energy scattered from a sample volume within the entrained gas flow reaches the first photodetector. This is important because it prevents particulate matter on the surfaces of the transparent windows from affecting the operating of the sensor.

Abstract: Oil mist detecting apparatus comprises a measuring chamber which receives air, and oil mist if present, from an engine compartment. The apparatus includes a radiation source which emits light into the measuring chamber, and the radiation sensor which is so disposed as to receive light scattered by oil mist in the chamber. A second radiation source is preferably provided for testing purposes, the second source being arranged to emit radiation directly to the sensor.

Abstract: A system for discriminating a precipitation pattern of particles comprises a transparent reaction container which has an inverted conical bottom surface. The precipitation pattern of particles of agglutination, non-agglutination and intermediate state between the agglutination and the non-agglutination are formed based on the immunologic agglutination on the bottom surface of the reaction container. The image of the precipitation pattern is projected through a lens to the electric converting element. A first photodetector is disposed at the center of the image projected on the surface of the photoelectric transducer element, four second photodetectors are disposed around the center of the image, and further five third photodetectors are disposed around the second photodetectors. A first detection signal which correspond to the difference of the outputs from the first detector and the one of third detectors is generated from a first subtracting unit.

Abstract: Apparatus for analyzing flowing fluid which contains light scattering particles comprises a light source; beam-expansion means to expand a light beam from the source to provide a two-dimensional sheet of light, there being at least a component of the fluid flow in the plane of said sheet; sensing means to sense light scattered by the particles; switch means arranged so that the sensing means senses scattered light only intermittently; and control and calculating means to calculate from the intermittently sensed light a property of the flow.

Abstract: A laser light beam is projected through a fluid measuring cell having a fluid accommodating chamber and inlet and outlet pathways for the fluid. The light is separated into transmitted light and scattered light. Separate light detectors sense the transmitted light and scattered light. An electric control circuit uses the variations of the intensity of the transmitted light to compensate for fluctuations in the intensity of the scattered light to provide an output related to the intensity of the scattered light.

Abstract: A method for measuring substantially spherical particles, such as dust. Two signals are formed, one of which is an approximately linear function of the particle concentration independently of the particle diameter and the second one is an approximately linear function of the particle diameter independently of the particle concentration. In order to obtain these signals the particles are illuminated with light in a direction different from their direction of flow. At least two detectors are arranged in such a way that the light in the beam path from the light source (3) to the first detector (6) is substantially only influenced by scattering and by light absorption of the particles and that the light in the beam path from the light source to the second detector (7) passes substantially only via reflections against the particles. The two signals are formed by definite relations between the d.c. voltage components of the output signals of the detectors and the average value of the squared R.M.S. value of the a.

Abstract: A nephelometric immunoassay and a nephelometer therefore, characterized in that light is projected on a sample to-be-measured containing an antigen-antibody complex, that at least two light scattering intensities at different angles with respect to the incident light are measured, and that a true antigen concentration is discriminated by comparing the light scattering intensities.

Abstract: An optical system for direct measurement of vorticity in a flowing fluid is disclosed. Spherical particles suspended in the flow rotate with an angular velocity that is accurately equal to half the local vorticity; thus, measurements of the rotation rates of such particles indicate the vorticity. The particles are transparent, and preferably are less than 50 .mu.m diameter, and each contains embedded planar crystal mirrors. The particles are suspended in a refractive index matched liquid. Measurement of the particle rotation rate and thus the vorticity of the fluid is preferably accomplished by measuring the rotation rates of reflections of one or more light beams from the planar mirrors. The measurements may be carried out using any system of position sensitive optical detectors such as photo sensitive devices screened by suitable slits or photo diode arrays.

Abstract: A nephelometer and method for measuring optical quality of a marine atmosphere and particularly characterizing its aerosol particle size distribution, visual range and aerosol optical effects in the visible and infrared. There is provided a housing for entrapping a momentary aerosol sampling, a laser source for providing a narrow collimated beam of radiant energy (usually light) through the sample, and plural spaced-apart cosine sensors facing across the radiant energy illuminated sample, with one reading a slightly greater angle than the other, for receiving aerosol particle scattered light. Integrated outputs from the sensors when compared with laser output intensity as a reference signal provide an indication of aerosol particle size distribution and concentration.

Abstract: The concentration of a selected gas specie at a situs determined by directing a laser beam at the situs, the beam including a wavelength within the resonance absorption band of the gas specie, and measuring the intensity of the laser beam energy scattered from two spaced volumes along said beam at the situs. The ratio of measured intensities is a relative measure of the concentration of the gas specie at the situs.

Abstract: A method of measuring volume of materials in suspensions in a liquid includes providing a sample of liquid containing particulate materials in suspension, passing a laser light beam through the liquid, the laser being diffracted upon exit from the sample, and measuring the diffracted light with at least two photoelectric cells positioned at differing distances from the central ray of the laser. Electrical signals F and F' from the photoelectric cells are produced and the volume (V) of materials in suspension is determined according to the relation Vd=aF+a'F', where d is the average minimum diameter of the particles and a and a' are respective balancing factors. An apparatus for carrying out the method, particularly as it relates to determining the quality of water, includes raw water and flocculating agent sources upstream from a purification station and at least one coagulation-settling system, which includes a pipe coupled to the supply sources and a settling tank in which flocs settle.

Abstract: An improved nephelometer is disclosed comprising a cruciform housing having therein helical flow diverters for providing a helical water flow pattern so as to cleanse the inside of a sample tube. A regulated light beam is incident on the sample tube and sample. The transmitted portion of the light is measured and used in a feedback loop to control the incident bulb intensity and the scattered portion of the light is measured to provide a measure of the turbidity of the fluid under test. The housing of the nephelometer is a hermaphroditic molding of plastic so as to simplify construction and assembly. All parts mounted within the nephelometer are located by recesses molded into the two halves of the housing. Amplifier circuitry for the output of the scattered light detecting photosensor is disclosed, as is lamp regulator circuitry for feeding back the value of the transmitted light, so as to adjust the incident light, for ramping the bulb on and off and for keeping it in a low current condition.

Abstract: In an apparatus in which particles are passed through an optical sensing zone to measure their radiant energy distribution such as, for example, light scattering characteristics for the purpose of identifying the particles, means and a method are provided for deviating the collected light in accordance with predetermined different paths to a plurality of different photodetecting devices. The deviation is effected independently of collection by optical radiant energy transmitting or reflecting means. The different photodetecting devices enable the measurement of energy directed along the particular path which is identified with that device. The paths are established by the deviating means rather than permitted to evolve by the scattering phenomena themselves whereby the photodetecting devices can be located in convenient arrangements and may be conventional in construction.

Abstract: A device for measuring the visibility, or diffusion coefficient, of atmosre air, including a light source for directing light onto a volume of air and a receiver capable of measuring the flow of light diffused by the volume of air. The source is surrounded by ambient air and furnishes a beam diverging in essentially all directions except within at least one dark cone. A receiver opening is directed toward the source, but is located in the dark cone so as to receive only diffused light. The apparatus is for use in meteorological installations, notably in airports.

Abstract: In an apparatus in which particles are passed through an optical sensing zone to measure their light scattering characteristics for the purpose of identifying the particles, means and a method are provided for deviating the collected light in accordance with predetermined different paths to a plurality of different photodetecting devices. The deviation is effected simultaneously with collection by optical radiant energy reflecting means. The different photodetecting devices enable the measurement of energy scattered along the particular path which is identified with that device. The paths are established by the combined collecting and deviating means rather than permitted to evolve by the scattering phenomena themselves whereby the photodetecting devices can be located in convenient arrangements and may be conventional in construction.

Abstract: The invention relates to a device for determining the granulometric composition of a mixture of particles by diffraction of light. The light flux received on the diffraction pattern is measured in a number of diffraction areas (AI,AJ) each of which is in the shape of an angular sector of circular rings which are concentric with the pattern, these integration areas forming two successions in each of which the inner and outer radii form geometrical progressions with common ratio of two, the ratio between the outer radius and the inner radius of an integration area being chosen in the interval between two and the square root of two, the radii within one succession (AJ) being equal to those within the other (AI) multiplied by the square root of two. Application to studying powder mixtures.

Abstract: Measurement of the energy and direction of radiation, typically scattered light, produced by particles passing through an optical sensing zone is improved in focusing of the scattered light and flexibility in the choice of focal length for positioning of photoresponsive devices.The improvement is obtained by collimating the collected scattered light entering a deviating device, typically a fresnel prism, and then focusing the emerging separate, independent beams for measurement.Collimation can be obtained using optical elements including lens systems or reflective systems such as those employing parabolic reflection.

Abstract: A light scattering oil-in-water detector and method. Scattered light is measured at a plurality of scattering angles, one angle being chosen such that the light scattered by the oil is substantially zero. This overcomes interference arising from suspended solids, e.g., rust.

Abstract: A rectangular sample cell for use in the measurement of the light scattered from an incident light beam in three mutually orthogonal directions is constructed with a prism having its base optically in contact with the sample along a side of the cell. Two other faces of the prism are oriented at equal angles to the base so that those faces pass orthogonal components of the light scattered at 90.degree. from the axis of the incident beam. The other orthogonal component is formed by the forward scattered light.

Abstract: This invention provides a dust particle analyzer comprising:A laser producing a light beam polarized in a first plane including said light beam;Means to convert said light beam into a cone light beam of a first small angle;Means to convey a volume of sample air containing dust particles under surveillance onto a highly illuminated region at the apex of said cone light beam;Means to collect light beams scattered forward from said dust particles in a first solid angle surrounded by the inner cone of a second small angle larger than said first small angle and the outer cone of a third small angle, the cosine of which is substantially equal to unity;Means to collect light beams scattered backward from said dust particle in a second solid angle surrounded by the inner cone of said second small angle and the outer cone of said third small angle;Means to produce a first signal which is proportional to the component of said forward scattered light beams polarized in said first plane and in said first solid angle;Mean

Abstract: A calibration/zero control is combined with an electro-optical measurement instrument in a time-multiplex fashion to provide a self-diagnostic in situ measurement system and automatic compensation of the entire electro-optical train without interruption of the measurement process. The electro-optical instrument includes a laser which provides a source of substantially monochromatic electromagnetic radiation (laser beam) and optics for collection and focusing radiation onto a detector. The radiation is directed through a sampling volume where it impinges upon an object whose properties or physical characteristics are to be measured by scattering techniques. The calibration/zero control includes an element rotatably positioned in the path of the electromagnetic radiation, optically upstream of the sampling volume, in having an axis of rotation perpendicular to the optical axis such that the radiation is periodically blocked and sampled.

Abstract: A photoelectronic smoke detector has walls around a dark chamber to which smoke, but not light, is admitted, and through which light is directed from an exciter light source on a path to a limited area of a chamber wall. A first photocell views light scattered from the through path by particles in the path primarily to produce an alarm signal, and also receives background light scattered from the chamber wall outside the limited area. A second photocell is disposed to receive background light substantially only from the limited area and other areas outside the source light path. The first cell produces a first signal in response to background and particle-scattered light. The second cell produces a second signal corresponding to background scatter. The first and second cells, preferably photovoltaic photodiodes, are coupled in opposition in a circuit whose output consequently is substantially independent of the background light.

Abstract: An optical concentration measuring apparatus and method which provides an output signal which is a substantially linear function of the concentration. The apparatus includes a chamber for containing a fluid sample and a source of optical radiation which develops a beam which is transmitted through the chamber and the sample. A first photoelectric cell is disposed to receive the transmitted beam for generating an electrical signal commensurate with the intensity of the beam after passage through the chamber and the fluid sample, and a second photoelectric cell which is disposed at a selected angle with respect to the direct beam for providing an electrical signal commensurate with the light scattered in a direction corresponding to the selected signal. The signal commensurate with the scattered beam and the signal commensurate with the direct beam are applied to a signal processor which develops a ratio of these signals, one of the signals being multiplied by a constant.

Abstract: The present invention is an improved multiple ratio single particle counter. Intensities of scattered radiation are measured at more than two angles and ratios of these intensities are derived. These ratios are compared with calibration curves to determine an unambiguous measure of the particle parameter.

Abstract: To characterize and differentiate large organic cells rapidly, individual particles are illuminated with monochromatic radiation of a wave length comparable to the size of the cell, producing a differential light scattering pattern about the illuminated cell. The pattern is sensed, preferably in the disclosed apparatus, by an array of detectors, and the sensed pattern employed as an identification and characterization of the cell. The pattern may be analyzed, or selected portions of the pattern employed, to differentiate cells embodying different features. The apparatus and process is especially useful for rapid identification and differentiation of leucocytes and other types of mammalian cells, the radiation for such analyses preferably being infrared radiation. A preferred structure for individually illuminating such cells with radiation and for sensing their differential light scattering pattern is disclosed.

Abstract: A method for linearizing the measurement of the volume loading of a fluid sample when it is determined by measuring the forward scattered light. The scattered light measurement which measures the volume loading is divided by a value related to a measure of the undiffracted light after it has passed through the sample.

Abstract: A turbidimeter for measuring the turbidity of a sample of fluid comprises a transparent sample cell, a light source for directing a beam of light through the sample cell, and beam separating means comprising a hollow tube and reflective means encompassing the tube. The hollow tube is positioned for receiving unscattered light transmitted through the sample cell and transmitting it to a light responsive detector. The reflective means is positioned and oriented for receiving light scattered by the fluid in the sample cell and directing it to a second light responsive detector. A comparison of the outputs of the two detectors provides a measure of the turbidity of the sampled fluid. This arrangement is compact, economical and shock-resistant, and it provides a measure of turbidity which is relatively unaffected by changes in color, the accumulation of turbid films on the sample cell wall and variations in the intensity of the light source.

Abstract: Apparatus for detecting oil in water contained in a chamber, wherein a semiconductor laser directs infrared radiation into the chamber. The radiation is scattered and detected by one or more cells. The output of one cell controls the gain of an amplifier connected from another cell. In one arragement, the outputs of two cells are connected to a differential amplifier, and the output of the differential amplifier is gain controlled by the output of a third cell.