Abstract: The test solution in the measuring cell is regarded to be divided into a plurality of sections, and the quantity of scattered light from each section is continuously measured to give a plurality of independent series of signal. This measurement is carried out by scanning the measuring cell with a minute light flux periodically to obtain a plurality of measurements in a period. Out of the series of signals obtained, those containing abnormal scattered light signal are eliminated to determine accurate concentration and reaction process.

Abstract: There is disclosed a particle analyzing apparatus having an irradiating optical system for irradiating a particle to be examined, flowing in a flow section of a flow cell, with a light beam, a measuring optical system for measuring the light scattered by the particle, an optical detection system for projecting a positioning light beam onto a determined wall of the flow cell and detecting the light reflected from the wall, and a device for varying the relative position of the measuring optical system with respect to the flow cell according to the output of the optical detection system.

Abstract: An optical detector circuit for a photometric instrument for providing a high precision, low cost A/D conversion of a detected optical signal. A sampled signal is integrated in a sample signal integrator while a reference signal integrator is integrated in a reference signal integrator. Using dual slope techniques, the integrated reference signal is provided as an input signal to the sample signal integrator during a de-integration cycle to provide a ratio of the detected signal to the reference signal, useful in nephelometers. An inverted blanking signal may also be integrated in the sample integrator prior to an integration of the sample signal to improve the accuracy of the dual slope integration. The period of integration is selected as a multiple of the primary sources of interfering noise such as power line and flourescent light frequencies.

Abstract: In a small particle detection system for use in detecting small particles, which float in a gas, by utilizing the light scattering effect thereof, a detecting cell is disposed in an external optical resonator which is adapted to resonate with the output light from a laser oscillator. When the detecting cell is disposed in the laser oscillating optical resonator, the position is selectively determined; the former is set in the position in the latter in which the diameter of a laser beam is minimal.

Abstract: A light scattering measuring apparatus utilizes light scattering to analyze physical properties of the surface and interior of an object, and particularly converts the scattered light therefrom into molecular vibrational energy or heat energy and measures the same. The light scattering measuring apparatus is provided with light applying means for applying an intermittent light to an object to be examined, a medium for absorbing scattered light intermittently emitted from the surface of the object by the applied light in accordance with the physical properties of the object to be examined and converting the scatterd light into molecular vibrational energy or heat energy, a detecting device for detecting the information regarding the energy produced by the medium, and a measuring device for measuring the molecular vibrational energy or the heat energy on the basis of a signal produced by the detecting device.

Abstract: Small particle diagnostic apparatus employing illumination by coherent light of high polarization ratio, polarized separation of the reflected particle scatter optical signals and the ability to consider particles in plural locations of a diagnostic aperture aided by use of a vidicon or other position-sensitive transducer device and an optional image intensifier device. Digital storage and analysis of the particle scatter data and computer control of the optical and analysis sequences are contemplated.

Abstract: A method of renewing a used liquid for reuse of the same includes establishing a body of a reference liquid for comparison with renewed used liquid, and establishing a separate body of the used liquid adjacent the body of reference liquid. An incident light beam is produced for consecutive traversal of the body of used liquid and the body of reference liquid, the particles in the two liquid bodies thereby diffusing the light beam to provide respective luminous fluxes off the axis of the incident light beam. The two luminous light fluxes are separately detected and compared. This procedure is automatically terminated when the detected luminous light fluxes are substantially equal to each other.

Abstract: A perfected laser nephelometer, characterized in that the measuring cell is comprised of a capillary tube (3) of which the inner diameter is close to the diameter of the laser beam (2).

Abstract: An aerosol sampling device and method are disclosed having improved sample flow characteristics. Sample flowing through an inlet nozzle is heated prior to discharge from the nozzle toward a measurement area to maintain sample flow more nearly laminar by compensating for the adiabatic cooling that occurs due to acceleration of flow through the nozzle. In addition, heating of the sample flow prevents condensation which can result with ambient air having a relative humidity of fifty percent. An optical particle measuring apparatus is shown having a generator for providing a laser beam, the path of which is through a measurement area, and an inlet nozzle through which aerosol sample is injected into the measurement area, after heating in accordance with this invention, to allow operation of the laser at a relatively high Q by reducing non-laminar flow characteristics.

Abstract: In order to test a laser rod for inclusions, which the usual interferometer oes not test, one of the interferometer mirrors is placed on a lens such that light scattered from inclusions in the rod passes through the lens to a detector.

Abstract: A particle counting apparatus includes a cuvette having a cylindrical bore therethrough and an exterior cylindrical surface the axis of which is perpendicular to the axis of the bore. The apparatus is adapted to detect light scattered from a particle that is small as compared to the wavelength of incident radiation and has an index of refraction close to that of the medium in which it is entrained.

Abstract: An automatic analyzing apparatus for effecting chemical analyses for various sample liquids such as blood, urine, and the like, comprising a sample delivery pump for metering a sample liquid into a reaction cuvette, a reagent delivery pump for delivering to the reaction cuvette a given amount of a given reagent selected from a plurality of reagents contained in a reagent cassette, to form a test liquid, a feed mechanism for successively supplying reaction cuvettes along a circular reaction line, a plurality of photometering sections arranged along the reaction line for effecting a plurality of photometric and/or nephelometric and/or fluorometric measurements for each test liquid at different time instances to produce a plurality of photometric results, and circuitry for receiving the photometric results and selecting therefrom given quantitative analytical data of a given test item.

Abstract: Method for the measurement of the difference in the optical properties dependent on the light direction of two samples (1,2), in which method one or several sources of light (3 to 6) as well as one light detector (7) are used. According to the invention, both of the samples (1, 2) are illuminated simultaneously and from both samples (1, 2) the light is passed simultaneously to the light detector (7). The lights to be measured from the samples (1, 2) have different directions in relation to the sample. The directions of the lights to be measured from the samples (1, 2) are alternated with each other at an appropriate frequency, such as a frequency within the range of 1 c/s to 10,000 c/s. The AC signal given by the light detector (7) is used as a measure of the difference in some optical property dependent on the direction of light between the samples, such as, e.g.

Abstract: Apparatus for measuring the colloidal stability of liquids comprising a sample-holder containing a sample of the liquid the turbidity of which is to be measured, a cooling tank containing the sample-holder and associated with a cooling unit, a laser light source of appropriate wavelength, a photopile for measuring the light flux diffused through the sample to be checked, a reference photopile for permanently controlling the exciting beam, a semitransparent mirror reflecting a part of the light beam in the direction of the reference photopile, a device for absorbing the nondiffused light and a logic system associated with a microprocessor for calculating the value of the turbidity of the sample.

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: The invention provides a photometric method of determining courses of reaction in a specimen, in which method the intensities of the transmitted light and of the stray light are measured, wherein the two intensities are measured simultaneously and the electrical signals corresponding to the transmitted light and to the stray light are combined to form one signal. The invention makes it possible to perform reliable measurement even with low levels of transmitted and stray light.The method is preferably used in determining the coagulation times of blood. Apparatus for carrying out the method is also disclosed.

Abstract: The invention concerns a light-optical detection device for determining the concentration of suspended particles in a gaseous medium within a light-tight housing. The latter essentially is formed by a short cylinder sheath having two front-surface coverings that are formed by a base plate and by an opposite cover plate. Cylinders extend into said housing for receiving, respectively, a light source and a photocell. The cylinders have axes which intersect at right angles at the center of the device. The axis of the cylinder containing the light source essentially runs in the direction towards the diagonally opposite corner of the interior of the device.

Abstract: The specific surface distribution of a pulp may be obtained by fractionating the pulp in a hydrocyclone means into an overflow and an underflow fraction and measuring the specific surface of each of the fractions and the amount of each of the fractions and based on a cumulative normal distribution relationship of cumulative weight fraction as a percent of feed to specific surface, determining the specific surface distribution for said pulp.Also disclosed is a method and apparatus for determining the specific surface of a pulp sample by measuring the light scattering characteristics to obtain a turbidity measurement of the pulp sample, measuring the consistency of the sample and determining the specific surface of said pulp based on the relationship of specific surface to the turbidity measurement for the measured consistency of the pulp.

Abstract: A light beam having a limited diameter impinges upon and transmits through an object and scattering light carrying information regarding the internal structure or composition of the sample is obtained from the sample. The scattering light is photoelectrically detected by a detecting system through an observation optical system.

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: 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: A method of the quantitative measurement of antigens and antibodies by reacting an antigen or antibody or a mixture thereof with the corresponding antibody and/or antigen which has been supported on insoluble carrier particles, irradiating the resulting reaction mixture with light of a specific wavelength to measure the intensity of light scattered by the reaction mixture.

Abstract: An improved nephelometer for immunochemical complex assay measures forward light scatter in samples. The angle of forward scatter, about 30.degree., is small enough to result in a large amount of forward scatter from the immunochemical complex particles which are to be assayed, whose size is of the order of the wave length of the light used in the optical system. Forward scattering from smaller particles, such as from molecules of buffer, antibody and serum, is constant during the course of a test, and is compensated for by the use of subtraction circuits which are readily and semiautomatically adjusted to subtract proper values, in accordance with the readings taken on standard or "blank" samples of buffer, antibody and serum. Forward scattering from large particles, such as dust, is variable, and results in fluctuating signals, which are electrically processed to ignore the spurious peaks. The results of a test are displayed on a digital read out meter.

Abstract: What is disclosed is an improved nephelometric method for detecting an antigen or antibody by contact thereof in a liquid medium with particles of a latex reagent comprising latex particles of different sizes loaded with different amounts of a corresponding antibody or antigen and then measuring the light scattered by a latex reagent.

Abstract: The present invention is a method and apparatus for counting discrete small objects suspended in a liquid stream. It comprises a source of flowing liquid having sufficient known velocity to maintain the objects in suspension, a means for introducing the objects into the liquid stream, and a calibrated turbidity measuring device. The outflow may be automatically shifted from one receiving means to another when a predetermined object count is reached. The method is particularly useful when counting living objects, such as fish fry or post-larval shrimp, since it eliminates the trauma of handling and is much faster than hand counting.

Abstract: A method of determining the percent solids and particle size distribution of a liquid suspension is taught. A purely optical method of making these determinations is disclosed which is independent of the physical nature of the particles in suspension.

Abstract: The specific surface distribution of a pulp may be obtained by fractionating the pulp in a hydrocyclone means into an overflow and an underflow fraction and measuring the specific surface of each of the fractions and the amount of each of the fractions and based on a cumulative normal distribution relationship of cumulative weight fraction as a percent of feed to specific surface, determining the specific surface distribution for said pulp.Also disclosed is a method and apparatus for determining the specific surface of a pulp sample by measuring the light scattering characteristics to obtain a turbidity measurement of the pulp sample, measuring the consistency of the sample and determining the specific surface of said pulp based on the relationship of specific surface to the turbidity measurement for the measured consistency of the pulp.

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: According to the invention, the instrument for measuring the sizes and quantity of particles in a fluid medium comprises a light-sensitive device which converts light scattered by particles in a flow of a fluid medium which crosses a beam emitted by a light source, as well as some part of the light of that beam, arriving from an element whose purpose is to simulate a calibrated particle, to electric pulses. The light-sensitive device is connected via a divider, whose purpose is to distribute pulses according to the sizes of particles, to signal inputs of respective threshold devices whose outputs are connected to inputs of counters with indicators. The element which simulates a calibrated particle is adapted to periodically change, in the course of measurement, the brightness of light received by the light-sensitive device.

Abstract: According to the invention, the device for granulometric analysis of particles contained in fluids comprises a feeding channel and a receiving channel intended for passage of a fluid under investigation. The two channels communicate with each other through a nozzle. The ratio between the diameters of the nozzle and the receiving channel is in the range of 1/4 to 1/7. The receiving channel is provided with transparent windows for passage of a light flux emitted by a lighting means through the fluid in that channel. The device further includes a light-sensitive means to receive light reflected from particles contained in the fluid.

Abstract: An apparatus for measuring and correcting the calibration characteristic of a photoelectric aerosol analyzer comprises a light guide disposed within a nozzle of the analyzer and having its one end arranged in the analyzer, said end face being made as a ball to provide for an even distribution of the light flux in the working zone of the analyzer. There are provided a controllable light pulse generator, adapted to measure and correct the calibration characteristic of the analyzer, and a meter to measure the intensity of the light flux in the working zone, said generator and said meter being installed, one at a time, above the other, flat, end face of the light guide.

Abstract: According to the invention, the device for granulometric analysis of particles contained in fluids comprises a flow-through chamber of an analyzer, a lighting means arranged outside the chamber, opposite a window which is transparent to light and provided in the wall of the chamber, said lighting means being intended to direct a convergent light beam through said window into said chamber, and a light-sensitive means intended to receive light reflected from particles contained in the fluid under investigation and arranged outside said chamber, opposite a second window provided in the wall of the chamber, which second window is transparent to reflected light. The second window is shaped as a cylinder whose axis is matched with the optical axis of the lighting means; the walls of the cylinder serve as walls of the chamber.

Abstract: An immunoassay wherein the sample containing an immunologic substance is added to a suspension of particles coated with a second immunologic substance which is specific to the immunologic substance of the sample. The change in percentage of light transmission through the suspension undergoing the resulting agglutination is measured for a predetermined period of time and compared to a standard graph. The suspension is under constant agitation during the measurement.

Abstract: A method of determining the need for post-addition of antigen or antibody to an antigen-antibody reaction to ascertain whether the reaction is in an antigen excess or an antibody excess condition. The time rate of change of a nephelometric signal developed from the reaction is monitored to generate a rate signal having a peak value providing a measure of antigen concentration. The post-addition step is performed only if the peak rate value is ambiguous--, i.e. if it indicates one antigen concentration value for a reaction in antigen excess but another value for a reaction in antibody excess. The need for the post-addition step is determined from measured qualities of the rate signal including one or more of (1) the peak rate value, (2) the elapsed time from the start of the reaction to the peak rate, and (3) the product of the peak rate and the elapsed time. When required, the post-addition step may be performed during progress of the antigen-antibody reaction after measurement of the peak rate value.

Abstract: An improved nephelometer comprised of a transparent cell for containing a liquid sample, a light source, and a detector is disclosed which reduces the amount of stray light reaching the detector. The cell is characterized in that either the illuminating light beam or the detected light passes through the cell wall face at an acute angle to the normal to the cell wall face.

Abstract: At least four beams of linearly polarized light are produced separately at one and the same point of measurement in a single direction of observation at right angles to a unitary sheet of a specimen of photoelastic material in order to determine the state of mechanical stress in the plane of the sheet.

Abstract: Disclosed is a radiation collector apparatus and method primarily for counting and analyzing a flow of dilute particulate material, such as blood cells, sperm cells and the like, through the use of radiation detection. The radiation collector apparatus comprises a reflector chamber having an ellipsoidal reflector surface with a pair of ellipsoidal foci defining a primary focus and secondary focus. A window is formed in the ellipsoidal reflector surface and is centered on a symmetry axis defined by the primary and secondary foci. In operation the radiation collector apparatus is provided with an intensified beam of radiation and a stream of particulate material aligned to intersect the intensified beam of radiation at one of the ellipsoidal foci. Detectable radiation, either directly or after one or more reflections, proceeds through the window in an organized beam for detection.

Abstract: An apparatus for the measurement of particulate scattering in fluids which is particularly suitable for low particulate concentration. The apparatus includes a housing with a cuvette for confining the fluid containing the particulate to be measured placed substantially at the center of the housing. A collimated light source provides a beam directed along an axis for illuminating the contents of the cuvette, and a light sensitive detector for receiving light scattered due to particulates along a selected axis. Surrounding the detector are a pair of equidistantly spaced baffles, of cylindrical or spherical configuration, which have a pair of aligned apertures centered about the scattering axis, and nonreflective facing surfaces.

Abstract: Apparatus for the measurement of hair-like particles, such as measurement of the amount of asbestos fiber in air. Apparatus including a source of a polarized beam of radiation directed to a scattering zone and a detector for detecting radiation of the beam scattered from the zone. A device at the zone, typically a pair of spaced parallel plates with an electric field therebetween, for orienting the hair-like particles parallel with each other and substantially perpendicular to the incoming beam of radiation, and a drive mechanism for rotating the polarized beam relative to the oriented particles to a first position with the polarization of the beam parallel to the particles and to a second position with the polarization of the beam perpendicular to the particles.

Abstract: A nephelometer including an optical excitation system for directing light through a first window area into a cylindrical glass container and an optical detection system for quantitatively monitoring light scattered by a substance within the container and passing therefrom through a second window area. The optical detection system includes a lens system in optical alignment with the second window area and focused on an optical dark region on an inner wall of the container opposite the second window area. The optical dark region is free of internal light reflections. Therefore, the light monitored by the detection system is scattered light from the substance substantially free of internal light reflections representing background error.