Abstract: An apparatus and method which provides a measure of the size distribution of particles dispersed in a fluid based upon an optimum combination of CLS measurements and DLS measurements. The measurement is characterized by relatively high resolution particle sizing. DLS data representative of the autocorrelation function, or power spectrum, of the detected intensity of scattered light for m measurement conditions of a sample, is optimally combined with CLS data representative of the average total detected intensity of scattered light for n measurement conditions, to provide an angle-independent, high resolution size distribution v(r), where m.gtoreq.1, n.gtoreq.0, m+n.gtoreq.2, and at least two of the measurement conditions are different. The size distribution may be expressed in terms of the continuous function v(r) or the histogram v, and may represent distributions weighted by mass, volume, number, surface area, or other measures.

Abstract: A photoelectric buffle detector apparatus (20) including a container (22) containing a liquid (24) having a top surface with a top side and an under side. A light emitting source (60) is positioned for emitting light toward the top surface (42) of the liquid (24). A light detecting source (70) positioned for detecting light emitted from the light emitting source (60) and reflected from the top surface (42) of the liquid (24). The light detecting source (70) outputs a signal indicating the presence of a wave pattern at the top surface (42) of the liquid (24) caused by gas bubbles rising to the top surface (42) of the liquid (24).

Abstract: A device and method are provided for determining the amount of solid material dispersed in a liquid. The device and method allow for the passage of a beam of light into the liquid containing the dispersed solid through the meniscus of a gas-liquid interface window which is formed. The meniscus is periodically or continuously renewed by a flow of gas. The scattering or transmission of the light through the liquid is then detected and provides a measurement of the amount of solid material dispersed in the liquid.

Abstract: Two photoelectric smoke detectors are arranged so that each smoke detector in turn verifies operation of the other smoke detector. Each smoke detector has a light source and a photodetector which is not directly illuminated by the light source. A smoke detection signal is issued when light from such a light source is scattered to the respective photodetector. The two smoke detectors are arranged so that a small amount of light from each light source illuminates the photodetector of the other smoke detector. A fault signal is issued when such a photodetector is not illuminated by the other light source.

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 coherent laser light flux is projected into a cell made of transparent quartz and light scattered from particles suspended in an antigen-antibody reaction liquid contained in the cell is detected by a photomultiplier by means of a collimator. An output electrical signal from the photomultiplier is sampled at different time instances and samplings are supplied to a fast Fourier transformer to derive a plurality of power spectrum densities of fluctuation in intensity of the scattered light. A plurality of power spectrum densities are averaged to generate a mean power spectrum density. An amount of antigen contained in the reaction liquid is measured in accordance with the mean power spectrum density.

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: A separation type light blocking smoke detector detects smoke present between a light emitting section and a light receiving section spaced therefrom by detecting blocking of light between the light emitting section and the light receiving section. The detector includes a light emitting section driving circuit, a counting circuit, and a storage circuit. The light emitting section driving circuit changes the emission intensity of the light emitting section in accordance with a predetermined changing mode for every repetitive cycle. The counting circuit includes a first comparator and an updating signal generator, and counts a physical amount corresponding to a period during which an output from the light emitting section falls in a predetermined range for each repetitive changing cycle. The storage circuit includes a second comparator and an AND gate, and stores a count value of the counting circuit in an arbitrary repetitive cycle.

Abstract: The security apparatus is mounted to objects to indicate when a person or moving body is in the vicinity. Detection of movement or vibration is determined by air bubble movement in a liquid charged chamber. Light emitting means radiating from end placements of the chamber cause lateral reflections from the end edges of the bubble. Detecting apparatus senses the differential in received bubble edge illumination and activates security warning equipment when there is imbalance due to bubble movement. Bubble dimension changes due to temperature variations are nullified by balance sensing. Automatic sensitivity control by sensing ambient light or under timer control allows security maintenance over changing environmental backgrounds. Remote supervision by radio link is an embodiment. Security of the radio communication is maintained by a process of carrier frequency division used for self modulation of the carrier frequency signal.

Abstract: Optical apparatus and methods are employed in the determination of impurity components present in both homogenous and non-homogenous light-scattering products. Light sources having wavelengths in the visible and near-infrared regions are preferred.

Abstract: A photoelectric smoke detector is equipped with a light emitter for radiating light into a measuring space. A light receiver detects scattered light caused by the presence of smoke in the measuring space. The measuring chamber is constructed as a light trap such that the light beam radiated by the light emitter is multiply reflected and cannot reach the light receiving element of the light receiver.

Abstract: The method of measuring the optical scattering co-efficient of the ocean by means of a laser beam (15) from a platform (16) above the ocean surface (3) in which an ocean penetrating beam (15) is swept across the direct path of travel to the surface of the ocean (3) and through it to the ocean bottom (4) to be back-reflected to the ocean surface (3) and to a receiver on the platform (16) characterized by changing the field of view to alternately use a small and a large field of view and calculating from the larger field of view an estimate of the absorption co-efficient and from the smaller field of view an estimate of beam attenuation co-efficient.

Abstract: A particle detector includes a laser, a beam shaping lens, and a pair of mirrors which reflect the shaped laser beam back and forth between the mirrors a selected number of times in order to create a sheet of light or light net between the mirrors. The path of the beam is terminated by a beam stop which contains a photodiode to monitor beam intensity and thereby system alignment. Light scattered by a particle falling through the sheet of light is gathered and transmitted to a photodiode. A peak detector provides a measure of the peak intensity of light scattered by such a particle to a microprocessor, which counts the number of particles falling through the light net in a selected time interval. The microprocessor also uses the peak intensity to estimate the size of the particle.

Abstract: A device and method are disclosed for optically detecting particles in a fluid. A fluid passage with transparent walls defining a monitoring volume, or region, is provided, and particles in the fluid are optically detected by directing a laser beam through the fluid in the monitoring region and collecting light scattered by the particles. A capillary is utilized as the fluid passage, and reflections from the walls of the capillary are effectively precluded. The laser beam is directed through the capillary by means of a window at the entrance side and a lens at the collecting side with the air-glass interfaces being outside the depth of view of particle monitoring within the monitoring region. As a result of this arrangement, the amount of scattered light is greatly reduced and a more uniform light signal is achieved which results in better size resolution of particles than has heretofore been achieved.

Abstract: Concentration of a smoke emanating from a combustion engine is determined by projecting beams of light on the flow of smoke in directions traversing the flow of smoke, detecting intensities of beams of light which have traversed the flow of smoke with a light receiving device and calculating a cross-sectional image of the flow of smoke based on detection signals issued by the light receiving device.

Abstract: A fiber optic probe having a sealed, cylindrical housing closed at one end by a transparent window and at the opposite end by a wall through which a plurality of optical fibers extend toward the window. Adjacent the window the fibers are radially and circumferentially spaced about the axis of the housing and converge along lines which intersect one another at a common point on the housing axis that is adjacent or beyond the outer surface of the window. At least one of the fibers transmits light from a source through the window to illuminate a zone of a fluid sample, whereby particles present in such zone scatter light therefrom to the remaining fibers for transmission through the probe housing to light detecting and measuring apparatus.

Abstract: An optical arrangement in photometrical measuring devices for use in fluorescence and absorption measurements, extinction, nephelometrical and turbidimetrical measurements comprises a light source for emitting a monochromatic radiation, a field aperture for said radiation, and lenses which focus said monochromatic radiation onto a sample material for being analyzed. The sample, in response to said monochromatic radiation emits a first radiation portion incorporating the measuring informations from said sample, and a second radiation portion not containing measuring information. An optical imaging system is provided for directing said first radiation portion onto a detector. A removable optical member for retaining the second radiation portion is provided adjacent the optical imaging system and has an aperture greater than the field aperture.

Abstract: In a light-transmission type smoke detector, a smoke chamber is composed of a disc-like block of a non-conductive material one side of which has a spiral groove and is coated with a conductive bright metal film and a casing mounted on the block, said casing having a plurality of labyrinth structure smoke entrances. An electric circuit system is placed on the other side of the disc-like block and is covered by a shield sheet. The shield sheet and the coating metal film are electrically connected to shield the electric circuit system.

Abstract: An apparatus is provided for measuring particle sizes between 5 and 50 microns in size and between 10 and 4,000 ppm in concentration prior to dilution of the sample, and upwards to at least 50,000 ppm with dilution of the sample. It is comprised of a laser light source, a square or rectangular sample cell and a photodetector which feeds data to some form of digital processor. The laser light is polarized and the return scattered light is polarized in the same plane. This device functions on the principle that particles in a light beam are capable of scattering the radiation in that beam and that the scattered radiation can be correlated to the physical properties of the scattering particles, specifically size and number.

Abstract: An improved fire alarm system utilizes receiver and fire detecting terminals connected thereto through a signal transmission line comprising two wires. The fire detecting terminal operates on two mode, one being a contact-closure mode of transmitting to the receiver a level signal whether or not a significantly higher fire-indicative quantity is detected, and the other being intelligent mode of transmitting a digital signal indicative of the sensed quantity in the form of a superimposed signal upon the level signal in answer to the instruction from the receiver for precise and convenient analysis thereof in determining fire presence on the side of the receiver. The fire detecting terminal includes a comparator having its own threshold with which the value of the sensed analog quantity is compared for providing the level-shifted signal when the sensed analog quantity has a level higher than the threshold, notifying fire presence independently of the intelligent mode.

Abstract: In a vacuum cleaner for industry and household in which the speed control for the blower motor for the vacuum cleaner is effected by evaluating the dust concentration given at any time in the suction line by opto-electrical means (light transmitters, light receivers) it is proposed to use the signal pulses, which are derived from the light receivers depending on the measured dust particles, for controlling an additional light transmitter (luminous diode) which directly coacts with a light-sensitive resistor which is at the same time part of the control resistance of a triac connected in the motor circuit of the blower motor. Preferably, the optoelectrical dust concentration measuring arrangement may comprise a plurality of light transmitters and light receivers and may be arranged directly adjacent to the air intake opening of a vacuum cleaner housing.

Abstract: An improved photoelectric smoke detector and alarm system which may be incorporated in a single station, completely self-contained unitary structure, or which may be incorporated in a multi-station detector system that is capable of self-contained operation but which can also be interconnected with other detectors whereby when any one detector's alarm sounds, all of the other alarms automatically sound in the other interconnected structures, the improved smoke detector and alarm system including a piezoceramic electrically activatable alarm, an illuminating circuit including a gallium aluminum arsenide light emitting diode, and a smoke sensing circuit including a pair of identical photoelectric cells formed on the same substrate with the photoelectric cells mounted in proximity to the light emitting diode whereby light emanating from the light emitting diode impinges upon one of the dual photoelectric cells at all times and impinges upon the other of the dual photoelectric cells to change the conductivity of

Abstract: An apparatus for measuring optical properties such as fluorescence, luminescence or absorption by a liquid sample includes collimating lenses disposed adjacent a cuvette so that their optical axes coincide with the central axis of the cuvette. A fiber bundle with an end portion is located adjacent to the lenses and is provided with a plurality of distinct light transmitting paths extending along the length of the fiber bundle to its end portions. The fiber bundle and collimating lenses cooperate to communicate collimated light between the sample and fiber bundle. The lenses are operable to focus light emanating from the sample upon the end portion of the fiber bundle so that an equal proportion from each volume element of the sample is incident on the fiber bundle surface.

Abstract: In a photo-electric smoke detector device, a first photo-detector receives the light emitted from a light emitter and scattered by smoke, and a second photo-detector directly receives the light emitted from the light emitter. The second photo-detector has an element surface on which trimmed electrodes are arranged. The electrodes of the second detector act to limit the amount of light emitted from the light emitter and transmitted to the elements of the second detector.

Abstract: An apparatus and method which provides a measure of the size distribution of particles dispersed in a fluid based upon an optimum combination of CLS measurements and DLS measurements. The measurement is characterized by relatively high resolution particle sizing. DLS data representative of the autocorrelation function, or power spectrum, of the detected intensity of scattered light at a plurality of angles about a sample, is optimally combined with CLS data representative of the average total detected intensity at those angles, to provide an angle-independent, high resolution size distribution v(r). The size distribution may be expressed in terms of the continuous function v(r) or the histogram v, and may represent distributions weighted by mass, volume, number, surface area, or other measures.

Abstract: A photoelectric smoke detector which operates on the scattered light principle and involves a light source, and a photosensor placed at an angle to the light beam such that it is normally not illuminated, the light source and photosensor being located within a dark detection chamber having air entry ports that restrict ambient light; smoke particles entering the smoke chamber produce interruption of the light beam, thereby scattering light onto the photosensor. The detection chamber is formed within a cup-shaped grill which can be readily removed from the housing by rotation of the grill to disengage a locking mechanism; the grill is provided with an end wall and, integrally formed therewith, spaced inner and outer cylindrical side walls, the inner side wall being defined by baffles which include scoop fins that are used to trap light, but which also function to scoop air into the chamber and cause air turbulence for mixing the smoke particles thoroughly; the outer side wall having windows for entry of smoke.

Abstract: A power station boiler condensate water monitor employs a light-scatter cell for the detection of oil and/or particulates in the water. In order to determine background scatter levels, provision is made to alternatively pass clean water through the cell (FLUSH). The offset voltages obtained from the detector outputs when clean water is employed are compensated for differences in temperature between the boiler condensate water and the clean water before substraction from the detector outputs when boiler condensate water is employed. The monitor is capable of detecting oil levels of less than 2 parts per million.

Abstract: A method for determining the onset of nucleation wherein a zone of a translucent fluid in which crystals may be formed is illuminated by a beam of light. When crystallization commences the crystals in the illuminated zone reflect and scatter light. Some of the scattered light is collected and transmitted to a light sensitive detector operable to generate a signal indicative of nucleation. Upon detection of nucleation either manual or automatic procedures may be instituted to modify the crystallization process in an appropriate manner.

Abstract: A light sensing apparatus comprising a solid-state photocell responsive to low levels of light connected to an impedance matching buffer stage, a gain controlled amplifier stage and an output amplifier stage; a gain control network controlled by a temperature sensor for receiving an amplified signal from said output stage, the gain being adjustable to compensate for temperature dependance of the photocell signal.

Abstract: A system for the simultaneous measurement of the size and velocities of bubbles or drops in a multiphase process environment wherein light passing through a Ronchi grating is projected onto a measurement volume within the multiphase process stream by a coherent fiber optic bundle and a gradient index imaging lens. Drops or bubbles passing through the measurement volume reflect or refract light which is sensed by velocity and size sensor fiber optic bundles disposed opposite the imaging lens and the sensed signal is coupled to signal processing means which convert the light signal to electrical signals and the appropriate size velocity measurments are made using one or more of the visibility techniques, phase lag techniques or transit time techniques.

Abstract: Method and apparatus are disclosed for determining one or more physical characteristics of individual bubbles in a gas-liquid system and a gas-liquid-solid system at high temperatures and pressures. An in situ probe device is inserted into the system over which individual bubbles flow. The probe device has a plurality of independent probes. Each has a rounded fibre optic end portion projecting into the system. A source of incident light is directed onto each of the probes. The rounded end portion of each probe is formed with a radius of curvature sufficiently large whereby the angle of incidence of the source light at the rounded portion is greater than the angle of total reflection for the fibre optic when in contact with the gas. The angle of incidence is less than the angle of total reflection for the fibre optic when in contact with the liquid. The plurality of probes are spatially arranged to detect one or more of the bubble physical characteristics as a bubble flows over the probe device.

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: An oil content monitor/control unit system is configured to automatically nitor and control processed effluent from an associated oil/water separator so that if the processed effluent exceeds predetermined in-port or at-sea oil concentration limits, it is either recirculated to an associated oil/water separator via a ship's bilge for additional processing, or diverted to a holding tank for storage. On the other hand, if the oil concentration of the processed effluent is less than predetermined in-port or at-sea limits, it is discharged overboard.

Abstract: In a smoke sensing apparatus, a light receiving circuit including a light receiving element senses light emitted from a light emitting circuit including a light emitting element and scattered by smoke, and a voltage holding circuit converts the output signal of the light receiving circuit into a d.c. voltage and holds the d.c. voltage. A mean value circuit averages the voltage signal from the voltage holding circuit, and a switching circuit acts to bring the output of the mean value circuit to a level close to that of the output of the voltage holding circuit. A comparison circuit compares the output of the means value circuit with the output of the voltage holding circuit thereby generating a control signal.

Abstract: A photoelectric smoke detector is provided with first and second radiation emitters and first and second radiation receivers. The first emitter emits pulsed radiation at a predetermined frequency. The second emitter emits pulsed radiation at twice this frequency. The first receiver receives the radiation of the second emitter directly and that of the first emitter by scattering only. When the first receiver receives alternate detection pulses reinforced by scattered radiation, an alarm is generated. The second receiver receives radiation directly from the first emitter and modulates the radiation output level of the second emitter proportionately. When the first receiver receives testing pulses between the alternating detection pulses, their level is discriminated to determine the functional state of the detecting elements and a corresponding function signal is generated.

Abstract: In a photoelectric smoke detector, a radiation source is driven intermittently by a control circuit and the radiation influenced by smoke particles, for instance scattered radiation, is picked up by a radiation receiver. The signal of the radiation receiver is transmitted to a signal processing circuit which is transmitted to a signal processing circuit which is simultaneously regulated by the control circuit. The signal processing circuit comprises a phase sensitive circuit which reverses or inverts the received signal according to the phase of the signal of the control circuit and transmits the thus modified signal to an integrating circuit. The integrating circuit controls a display circuit by means of its integrated output signal. The display circuit can, for instance, output an alarm signal when the integrated signal, i.e. the smoke intensity, exceeds a prescribed threshold value or can display the smoke intensity.

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 a scattered radiation smoke detector (D) the energy supply from the evaluation unit (A) and the signal returned thereto take place exclusively optically by means of radiation conducting elements (L.sub.1, L.sub.2) and all electrical components are situated in the evaluation unit (A) remote from the smoke detector (D). An approximately parallel transmitting or reception zone of small diameter is generated by collimating devices (4, 6) disposed at the ends (3, 8) of the optical conductors and thereby the interference radiation level in the smoke detector is reduced and the sensitivity increased. Since the smoke detector (D) comprises no metallic components, it is insensitive to temperature and corrosion and is especially well suited for application in environments subject to the danger of explosion and electrical interference.

Abstract: A method of imaging the surface of an object at high temperature includes the steps of: irradiating the surface of a high-temperature object with two different kinds of pulses of monochromatic light of a fundamental wave and a harmonic thereof; passing the reflected light from the surface of the object through both an interference filter which allows only the two different kinds of monochromatic light to pass and a high-speed optical switch thereby to remove any background light component; drawing out only the reflected light of the pulses and leading the same to an image generating mechanism where it is converted into an image; and controlling the voltage applied to the high-speed optical switch thereby to adjust the mixing ratio between two wavelengths.

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 photoelectric smoke sensor terminal has an address signal detector for detecting whether or not an address assigned to the terminal coincides with an address represented by an address signal from a main unit. Only when the coincidence signal is supplied to a switch circuit is a photoelectric smoke sensor turned on. The terminal also has an item data memory for supplying item data (e.g. gas leakage and smoke generation data) so that a plurality of item data signals together with an output signal from the sensor can be transmitted on a single transmission line.

Abstract: A photoelectric combustion products detector for periodically sampling the ambient air includes a sampling circuit capacitively coupled to an AC source, so that the coupling capacitor produces at the sampling circuit a source current 90.degree. out of phase with the AC source voltage, which is rectified to provide a supply voltage. Sampling is controlled by a NAND gate having at its inputs a varying threshold level which is proportional to and in phase with the supply voltage. A ramp signal generator connected to one gate input terminal enables the gate when the ramp signal exceeds the varying threshold level. The other input terminal of the gate is connected to a timing circuit comprising a Zener diode, a capacitor and a discharge resistor which produces a short trigger pulse at or near each positive zero crossing of the AC source voltage, the coincidence of a trigger pulse with an enabling period causing the gate to actuate the sampling circuit.

Abstract: A photoelectric smoke detector including a housing defining a test zone and an opening for admitting smoke thereinto, a light source arranged to direct light to the zone and a light responsive element arranged to receive light scattered by smoke particles in the zone. An optical barrier prevents the direct transmission of light through the zone and between the light source and light responsive element, the barrier defining a light passage for transmitting light directly therebetween. Projecting into the light passage is a mechanical gate that can be adjusted to alter the size of the light passage and thereby vary the level of light transmitted directly therethrough between the light source and the light responsive element. In response to selective adjustment of the mechanical gate, the light responsive element can provide a background signal that obviates normal electronic noise.

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 present weather observing system including a radiation source for providing a beam of radiation in the atmosphere and a detector for detecting scattered radiation from suspended or precipitating particles within a sample volume, the detector having a field of view intersecting the beam to define the sample volume. The invention further includes a device for determining the size and velocity of at least one particle precipitating through the sample volume, and an element responsive to the device for determining size and velocity for identifying the type of precipitation.

Abstract: A flow cytometry apparatus for determining one or more characteristics of particles or the like flowing in a liquid stream includes a nozzle for generating a liquid flow stream for moving particles therethrough substantially one at a time. A light source provides a spectrally rich beam of light directed toward the particles moving in the stream. A dispersion prism separates the spectrally rich light into a plurality of spatially separated components thereof so as to selectively illuminate the particles with one or more of the separated light components. A detector is included for detecting light with respect to each moving particle and for associating the detected light with one or more characteristics of that particle.

Abstract: A first syringe pump feeds a sample solution such as, for example, a diluted blood into an inner tube of a flow cell, and a second syringe pump feeds a sheath solution such as, for example, a physiological saline solution into an outer tube of the flow cell. Respective first and second plungers of the first and second syringe pumps are fixed onto a connecting plate. The connecting plate is supported by a pair of guide rods so that it may be moved in line with the moving direction of the plungers. Into the connecting plate is screwed an externally threaded rod, which is driven by a motor to rotate in the normal and reverse directions about its axis. By the normal and reverse rotations of the threaded rod, the connecting plate is reciprocally moved, whereby the first and second plungers are moved at the same speed. By the movement of the first and second plungers at the same speed, the sample solution and the sheath solution are respectively fed into the flow cell at the same rate.

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: Vacuum cleaner for use in industry and household comprising a housing and an electric motor driving the blower generating the working vacuum, and optional maneuvering means for moving a suction nozzle over the material to be cleaned. There is provided in the area of the channel passed by the dust and dirt particles drawn in, an optical sensor comprising a light transmitter and a coacting light receiver so that the quantity of the dust and dirt particles drawn in at any time is detected. After comparison of the value so determined with a given threshold value, either a visual and/or an acoustic signal are obtained and/or a power variation of the electric motor driving the blower is effected.

Abstract: A method of obtaining data for mathematical characterization of a wave surface by transmitting a beam toward the surface so that the beam is reflected from an element of the surface in a direction determined by the instantaneous, two dimensional slope of the element. The reflected beam impinges on a screen as a spot whose time varying coordinates correspond to the time varying slope of the element. These coordinates are captured by scanning the screen with a raster scan which controls counters identifying the spot position. The instantaneous distance is measured by a capacitance probe to relate the captured coordinates to the corresponding angles of reflection by appropriate trigonometric relations.