Abstract: The turbidity of liquids, including oil contaminated water, may be measured by an apparatus having a first elongated shell member defining a turbid liquid measurement chamber and opposed head members forming windows for transmitting a light beam through the measurement chamber between a light source and photosensitive element. A second shell member is disposed around the first shell member and defines with the first shell member and the opposed head members clear liquid supply chambers for supplying a clear liquid to wash over the windows and prevent contact of the turbid liquid with windows during operation of the apparatus. A flow of clear liquid, such as water, may be controlled by a pump and a throttling valve with orifices in each flow line to limit the flow of clear liquid. A mixture of clear liquid and turbid liquid is discharged from the turbidity measurement chamber into a discharge manifold formed between the shell members.

Abstract: A device for determining the characteristics of particles in suspension in a liquid, comprising a sampling device (2) for injecting samples of particles; a fractionator (3) for sorting those particles as a function of their length; an optical measurement cell (4) which receives the output of the fractionator, and a programmable controller (6) for calculating the values of the intensities and combinations of those values in the various directions of the optical radiation. The optical measurement cell includes a laser for transmitting polarized, coherent light through the particles in suspension and for collecting the light diffracted in various directions.

Abstract: A system for analyzing bulk cotton or other flowable solids comprising moving the cotton through a conduit; halting part of the cotton within the conduit while permitting the remaining part to continue movement through the conduit; moving the halted mass in an arcuate pathway toward an interior surface of the conduit; pressing the halted mass against the interior surface; wherein the pressing means is sufficient to press the mass against the interior surface to form a face of uniform cotton density on that part of the mass which is pressed against the interior surface; analyzing such face for a property selected from the group consisting of color, trash content, moisture content, and combinations thereof; and thereafter releasing the pressure on the halted mass to allow it to resume movement through the conduit.

Abstract: A luminometer comprises a body which is formed with a bore for receiving a sample container and a cavity communicating with the lower end of the bore. A control device having a part-circumferential ramp is rotatable within the cavity for displacing the sample container along the bore to and from a test position in which the sample container is exposed to a photo-multiplier device. The control device is rotated by a cap which is coupled to the control device and which covers the upper end of the bore in light-tight manner as the control device lowers the sample container to the test position.

Abstract: An apparatus for detecting and counting particles in a gas stream flowing at a preselected rate, wherein the apparatus includes a multi-tier inlet manifold and a plurality of sensors. The inlet manifold divides an aggregate sample flow into a plurality of substantially identical partial sample flows. Each partial sample flow enters one of the functionally duplicative sensors and is intersected by an incident beam to define a view volume. Particles contained within the partial sample flows scatter light as the particles pass through the view volume. The scattered light is directed to a photodetector which provides a signal having characteristics corresponding to the sensed light. Particle detection in each view volume is operationally independent of the others, but the information is combined to provide a total particle count of the aggregate sample flow.

Abstract: A flow cell for use in highly corrosive environments is constructed from a cross union and contains opposing probes each with an external sapphire window which is sealed into a metal tube contained in each probe with melted glass and an optional plastic seal over the melted glass. Each portion of the cross union containing a probe has a right angle shoulder which abuts the end of the tube containing the sapphire window. An O-ring gasket is positioned between the right angle shoulder and tube end to form a tight cover over the glass seal when the probes are assembled in the flow cell, thereby protecting the glass seal and plastic seal from the corrosive environment.

Abstract: An optical probe is for measurement of light transmission of liquid. A tubular housing three equally configured legs defining three arcuately spaced openings in the housing wall. A solid cylindrical member formed of glass or fused silica has a flat transparent end surface and an opposing curved surface silvered to form an internally concave reflector. The cylindrical member is retained in the housing with the transparent end surface adjacent to the openings. A transparent rod member has a flat first end surface and a flat second end surface parallel to the first end surface. The rod member is retained in the housing with the second end surface adjacent to the openings and spaced from the transparent end surface parallel thereto so as to define a cavity therebetween such that, upon immersion of the probe, liquid passes through the openings into the cavity. The first end surface is spaced from the concave reflector so that conjugate focal spots of the concave reflector are located at the first end surface.

Abstract: An improved apparatus for measuring fine particles in a liquid includes a nozzle for spouting water from within one end of a cell towards an opposite end thereof. An incident light beam traverses the spouted water to scatter light towards a light detection system exteriorly of the cell. The detection system includes a stop for excluding scattered light from being detected and which resulted from fine particles outside a central portion of the spouted liquid.

Abstract: A non-dispersive infrared gas analyzer especially adapted for measuring the concentrations of HC, CO and CO.sub.2 in a vehicle exhaust includes a sample chamber for holding a sample gas, a radiation emitter for directing a beam through the chamber and a detector for indicating the amount of radiation absorbed. A plurality of filters, each of which transmit radiation at an absorption band of a gas component to be detected, are alternatingly positioned in the radiation path to produce a time-multiplexed signal having concentration information for all gases. A calibration assembly is provided which includes a plurality of calibration cells selectively positionable in the radiation path in order to provide an internal calibration standard for two-point calibration of each gas channel. The cells contain one or more of the gas components to be measured at concentrations and pressures predetermined to compensate for the difference in optical path length between the calibration cells and the sample chamber.

Abstract: A turbidimeter includes a housing having a cavity with an inlet through which the fluid enters the bottom of the cavity, and an outlet through which the fluid exits the top of the cavity. A removable baffle assembly is located within the cavity between the inlet and outlet. The baffle assembly is formed by three vertical plates spaced from each other and extending across substantially the entire cross sectional area of the cavity. The first plate defines a first passage near the top of the cavity through which all the fluid entering the cavity must flow. The second and third walls define a second passage near the top of the cavity through which gas bubbles entrained in the fluid travels to the outlet. A third passage is defined between the first wall and the outlet and a mechanism is provided for measuring the turbidity of the fluid flowing through the third passage. A calibration device formed by a block of glass ceramic material is insertable in the third passage to simulate a known turbidity fluid.

Abstract: An optical system comprising a cavity for spectrophotometric measurements and the like with a first cylindrical refraction index gradient lens matched to an optical fiber. A second cylindrical refraction index gradient lens is provided disposed approximately coaxial to the first lens. The first and second lenses are spaced apart to delimit the cavity between opposite faces of the first and second lenses. A sample under test is positioned within the cavity. A reflecting surface is provided on the face of the second lens opposite said cavity.

Abstract: A photometric probe or a photometric cell having separate windows and a metallic probe body or cell body. The window(s) are sealed to the probe or cell body by brazed or frit seals which are less likely to leak after extended use in high temperature and/or high pressure industrial applications than probes and cells having gasket sealed windows. The windows can be made of sapphire, cubic zirconia, diamond, ruby, glass or quartz and, in the case of the probe, can be in the shape of an Attenuated Total Reflectance prism. The probe or cell body can be Kovar alloy or stainless steel.

Abstract: A windowless flow cell for detecting substances in a flowing fluid stream by chemiluminescence, fluorescence or absorption in flow injection analysis schemes, liquid chromatographs, or gas chromatographs is described. Furthermore, the mixing characteristics of the invention suggest its use as a micro-volume mixing chamber for a variety of experiments.A windowless flow cell comprising an upper body plate, upper wire spacer, mid-body plate, lower body spacer plate, and lower body plate interconnected by anchor bolts is described. Cell wires are attached to the upper body plate and the lower body plate. A primary reagent port through the upper body plate, with secondary reagent port and tertiary reagent port through the mid-body plate provide the fluids to be mixed. A thin film of the mixture of fluids to be examined flows down the cell wires through the examining chamber and through the drop detector and overflow detector prior to exiting the drain port by way of a low vacuum source.

Abstract: In accordance with the present invention, radiant energy is transmitted to a probe element including an interior conical reflecting surface and a fluid sample chamber. Portions of the light which have been transmitted, partially attenuated, or scattered by a fluid sample in the sample chamber are directed by at least a portion of the interior conical reflecting surface to a location for collection of the transmitted, partially attenuated, or scattered light. A stilling valve incorporated into the probe element enables elimination of entrained gas bubbles from the chamber.

Abstract: An improved sampling system is provided for on-line monitoring of a liquid such as a process liquor in a paper mill or the like. The sampling system includes, in general terms, an improved sampling probe for circulating process liquor from a process tank or the like to a sensor device such as a refractometer for monitoring of selected parameters. The sampling probe includes intake and return conduits having ends nested within an open-ended probe housing disposed within the process tank, such that the intake and return conduit ends are shielded from direct contact with large particulate settling within the tank. The intake and return conduit ends are further arranged for intersection of liquor flow streams associated therewith at a position inset within the probe housing to generate turbulence which tends to sweep large particulate away from the probe while maintaining smaller particulate in suspension to avoid probe clogging.

Abstract: Light generated by an illumination source (26) travels through a fiber optic cable (40) to optrode (14) which is immersed in the process fluid (16) to be analyzed. The optrode collimates the light beam before it crosses the sampling gap (68) where the beam transects the process fluid to be analyzed. As it crosses the sampling gap 68, the light beam is absorbed in a specific wavelength band by the chemical species in solution. The collimated beam is then picked up by an opposing collimated lens in the optrode and transmitted to the protected analytical module (20) by a second optical fiber (42).

Abstract: A micro-flow cell for chromatographic, spectrometric or scintillation measurements comprises a capillary tube, preferably made of glass or silica glass, through which flows the medium to be examined, and a holding device for said capillary tube. The holding device is separably composed of at least two parts which can be separated in their longitudinal direction. The capillary tube is fixed in the holding device by suitably formed connectors so as to be stress-free and tension-free to the greatest possible extent.

Abstract: A unique method and apparatus for dispensing tablets having particular application in the clinical analysis of biological samples. A series of containers are advanced past a plurality of processing stations, one of which is a table dispenser in turn. The processing stations are selectively activated by a controller. A sensor is associated with the tablet dispenser and is arranged to detect whether a tablet has actually entered a container. The sensor is activated only when the tablet dispenser is activated. The controller is responsive to the sensor in dependence upon the condition sensed by the sensor.

Abstract: Apparatus for measuring concentration of liquid developer or the like includes a holding member formed with an opening in which the liquid to be measured is retained. The holding member is driven to pass through a measuring station in which a photoelectric detector is disposed. The detector determines the amount of light transmitted through the liquid retained in the opening, thus measuring the concentration of colored component in the liquid.

Abstract: The invention relates to an arrangement for measuring the concentration of gaseous and/or vaporous components of a fluid mixture by means of light absorption such as by means of an infrared absorption by utilizing a membrane which is made of a material in which the component of the fluid mixture to be measured accumulates. The membrane is transparent to the measuring radiation and is selectively permeable for the particles of the compounds to be measured. The membrane further acts on the radiation path between the light source and the detector. The arrangement is improved with respect to selectivity and the detection sensitivity. This is achieved in that the membrane is mounted in the flow path of the fluid mixture such that the flow path is subdivided into two component paths at the surfaces of the membrane.

Abstract: An analytic instrument for kinetically measuring light absorption characteristics of a plurality of independent samples contained in disposable test tubes arranged in a circular pattern about a single light source. The instrument is designed to be used with a host personal computer and is not specific to any particular type of assay. The instrument obtains and temporarily stores raw data in the form of digitized output signals from the plurality of photodetectors and periodically passes them to the host computer. An incubator has test tube wells arranged in a circular array equidistant from a single incandescent light source. The circular symmetry controls the thermal gradients in the incubator such that all of the samples are disposed on the same isotherm and all of the photodetectors are disposed on the same isotherm.

Abstract: For use in a spectrophotometry or spectrofluorimetry system, where a fluid to be analyzed, is passed into or through a tube having at least one branch, a plastic device insertable into said branch, said device comprising a tubular plastic member the inner end of which is closed by a transparent transverse end wall, extending into the tube branch and within which an end of a fiber optic cable is removably secured with such end disposed in facing engagement with the inside of said wall, and a detector cap defining a chamber to hold some of the fluid or a dye color reactive to such fluid, is secured on the opposite side of the end wall. The tubular plastic member is removably securable in, and closes the tube branch.

Abstract: An apparatus for measuring a property of a liquid comprises at least one guide for electromagnetic radiation, means for directing electromagnetic radiation into the guide, means for providing at least one drop of liquid in contact with the guide at a position where radiation from the guide can enter the drop, and means for deriving a signal which is a function of the interaction of the radiation with the liquid of the drop.

Abstract: The present invention comprises a simple multi-purpose on-line system for monitoring the concentration and/or the total amount of an organic analyte species or inorganic analyte species in an aqueous solution. The on-line detection system comprises a detection column and a sensor mounted around the detection column. The sensor consists of an electromagnetic radiation source (typically a light source) and an appropriate detector for the electromagnetic radiation. The response from the detector drives an electric circuit, which provides a signal to a recorder as well as a means to trip an alarm system and/or a process system.

Abstract: In an apparatus for determining the concentration of foreign matter in a water stream, a stream of liquid is bypassed through conduits both before and after the pipeline block for the process and each stream is pumped into a cell, a beam source being associated with each of the cells whose beams penetrate the cells and are led by a beam splitter both to a first detector and to a second detector, the electrical signals of the detectors being compared by an electrical circuit and processed to a recognition signal. To make a bubble-free sample stream possible, magnetically actuated valves are inserted into the return lines which are connected to the cells, and the signals for opening and closing the valves are produced by a frequency generator.

Abstract: The invention relates to photometric apparatus and method for determining a characteristic of individual ones of a plurality of samples contained within a plurality of sample chambers. The photometric apparatus includes an enclosure; a substantially uniform source of radiation coupled to the enclosure such that a plurality of sample chambers, disposed within the enclosure, are simultaneously illuminated by the uniform source; and apparatus for detecting an amount of radiation which is transmitted through individual ones of the sample chambers, the detecting apparatus having an output signal having a magnitude which is a function of the amount of radiation which is transmitted through an individual one of the sample chambers.

Abstract: This invention relates to an instrument for the detection of microorganisms in a culture media by means of the measurement of the gaseous products generated during bacterial metabolism, without the need for extracting the products of metabolism from the culture vessel in order to perform the measurement. A special vial containing a gas-liquid separation system permits the measurement through the walls of the vial by determination of the infrared absorption by the gaseous contents within the vessel. While intended primarily for blood-culture testing, the method is applicable to other microbiological and physical chemistry investigations where changes in gas concentrations must be determined in a simple, convenient manner. An alternate embodiment is shown and described whereat a high concentration of gas is present and the infrared energy path is too long for accurate measurement.

Abstract: A process cell (1) for the analysis of liquids, particularly cloudy ones with high light absorption, has a measuring chamber (2) through which flows said liquid, which has two windows (3) lying at a short distance opposite each other for the passage of the measuring light. The latter are held in holding devices (4) which are supported by a common frame (5), which is sufficiently movable relative to the cell housing (6) to be able to perform heat movements. The frame (5) and the holding devices (4) consist of a material with essentially the same coefficient of thermal expansion, so that changes in length of the holding devices (4) occurring upon temperature changes can each time be compensated so that the distance between the two windows (3) practically does not change and thus no changes in the measuring results determined by temperature fluctuations occur.

Abstract: For higher-speed absorbancy measurement, first and second rotating mirrors are attached individually to the opposite ends of a rotating shaft which is arranged vertically in the center of a reaction-tube table and driven by a motor. A light beam from a prelocated light source, for example, a lamp, is transferred along the axis of the rotating shaft to the first rotating mirror. Reflected by the first mirror, the light beam is applied to a reaction tube, and is reflected by a reflector which is attached to the tube. The light beam reflected by the second rotating mirror on the rotating shaft is transferred along the axis of the shaft to a photodetector, and is detected. In such an arrangement, the respective absorbancies of reaction tubes can be measured in predetermined directions, with respect to the rotating shaft in the center of the reaction-tube table, by simply rotating the shaft.

Abstract: A light is applied to particles to be examined in a cell, the scattered light from the particles to be examined is converted to an afocal light, a beam splitter is provided in the afocal light beam, and photometering and observation of the cell are efficiently effected in two optical paths branched off by the beam splitter.

Abstract: A flow cell for a photometer, which comprises a cell body integrated from a pair of cell body members by joining, at least one of which is provided with a linear groove on the joining surface of the cell body member from one end to another to the full length, as exposed to the joining surface, the groove playing both roles of a liquid sample passage and a detecting light path by the integration of the cell body members, and is further provided with a liquid sample inlet passage at a position near one end of the groove and a liquid sample outlet passage at a position near the other end of the groove, both passages being communicated with the grooves, the linear groove being provided with a light reflecting layer to the full length of the linear groove, and a pair of light transmission window members joined with the flow cell body at both ends on the groove-open sides thereof is provided, where polishing of the grooves is readily carried out and random reflection of light or absorption of light due to poor refl

Abstract: Method and apparatus for generating centrifugal forces, including a plate rotatable about an axis, and at least one holding means mounted on the plate for rotation therewith, the holding means being adapted to receive an article to be subjected to centrifugal force and being rotatable relative to the plate member to permit the direction of centrifugal force acting on the article to be changed.

Abstract: Monitoring concentration of components of blood flowing through a flowpath including flowing the components through a transparent channel, directing light to the channel along an axis intersecting the channel, detecting light passing through the channel along the axis, detecting light scattered off of the axis, and determining concentration of components based on the light passing along the axis and/or the light scattered off of the axis. Also disclosed is a movable cover to block ambient light from a photodetector after mounting of a removable transparent flow channel.

Abstract: A method of and apparatus for an automatic dilution system for providing a variable dilution of an unknown sample material, including a mixing chamber having at least one input and output, sample material and diluent. Injecting a quantity of the sample material into the input of the mixing chamber. Providing a flow of the diluent into the input of the mixing chamber to mix with the sample material and to continuously dilute the concentration of the sample material within the mixing chamber and flowing out of the mixing chamber to provide a variable dilution. Providing a measurement of a particular characteristic of the continuously variable diluted sample material, and controlling the flow of diluent in accordance with an optimal measurement of the particular characteristic.

Abstract: The sample air inlet nozzle into a particle counter test cell is formed with an elongated, flattened tip to provide a thin, flat laminar flow jet which intersects a laser beam. A secondary tube surrounding the nozzle provides a sheath of air which helps maintain the jet shape.

Abstract: A gas measuring and warning apparatus is disclosed having a testing tube through which the gas that is to be detected flows. The apparatus also has a photoelectric scanner for detecting the migrating reaction zone. The configuration of the apparatus is simplified and the resolution capacity is improved. This is achieved in that the photoelectric scanner includes an image forming lens system which forms an image of the length of the reaction zone on a photosensitive array of identical sensor elements, the reaction zone being illuminated by at least one light source. For emitting a measured signal, the evaluation circuit is controlled by the number of sensor elements that are located within the imaged length of the reaction zone.

Abstract: An apparatus for directly monitoring microorganisms present in a liquid crises a window glass with one face in contact with the liquid. Near the other face is disposed a TV camera having an optical magnifying system for monitoring the microorganisms. A sample cell or a narrow space is formed on said one side of the window glass for direct introduction of a sample of the liquid. The sample is statically held in the cell even though the liquid is in movement. The sample is purged from the cell by feeding a cleaning fluid thereinto or by vibrating or otherside exerting physical movement on the cell, whereafter a new sample is introduced into the cell. Purging of the sample cleans the cell and is prevents it from being smudged with dregs, dirt or the like included in the liquid.

Abstract: An automatic observation system for observing objects such as microorganisms contained in a liquid supplied from a container. A sample of the water is fixed between two glass plates, one of which is movable relative to the other by a plunger. A condensor lens is also carried by the plunger. Light from a continuous-output illuminating source is applied through the condensor lens via an optical fiber.

Abstract: A photometer head having a housing for receiving and supporting small test volumes. The housing includes a recess and a plate for substantially covering the recess. A light transmitter and a light receiver having first and second end surfaces are mounted within the housing and project into the recess at locations substantially opposite one another to define a gap between the first and second end surfaces for retaining the small test volumes. A liquid applicator extends through an aperture in the housing to dispense droplets of liquid test volumes into the gap. The light transmitter directs optical energy at the droplets and the light receiver receives the transmitted energy.

Abstract: The invention is directed to a through-flow cuvette which can be assembled and wherein the cuvette body is made of two cuvette halves. The cuvette halves are placed one atop the other at their planar surfaces. Convex recesses are formed in these planar surfaces and define the inlet and outlet channels as well as the measuring space.

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: The present invention concerns a device for analyzing chemical substances and monitoring chemical reactions in which cuvettes on a turntable are rapidly scanned by light at test and reference wavelengths and intensity of the light after passage through the cuvettes monitored by a photodetector. The output of the photodetector is logically processed so that measurements can be made of the varying optical densities in the samples scanned.

Abstract: Apparatus and method for measuring the density of sperm in a sample and for calculating the magnitude of dose required for artificial insemination. An optical assembly with light source, specimen holder and photodetector providing a signal to an amplifier the output of which is proportional to absorbance of the sample. A signal selection system utilizes three parallel signal channels with each having a different correction factor for matching the absorbance signal to actual density count, and including means for selecting the appropriate signal channel as a function of signal amplitude, with the output when calibrated providing the direct reading of the sperm density. Knowing the number of sperm cells desired per insemination and the percent motility of the sample sperm, the required dose is calculated as a function of the density count.

Abstract: A fluid sample cell for the spectroscopic analysis of a sample includes a fluid-tight sample compartment defined by a radiant energy transmissive top, a side wall, and a bottom having a reflective surface. The bottom is heat conductive and comprises an external surface which defines a hollow well adapted to receive a hot plate. A fluid sample cell is also provided wherein a side wall of a sample compartment defines an entry port and an exit port such that, when the cell is in a substantially vertical position, one of the ports is located above and one below the compartment. A fluid sample cell is also provided wherein a side wall of the sample compartment is provided with a pocket for collecting impurities when the cell is in a substantially vertical position, wherein the pocket is disposed above and/or below the sample compartment.

Abstract: Particle distribution in a fluid flowing through a microscopic tube is achieved by flowing the fluid vertically-downward through a transparent capillary tube and passing light through the flowing fluid. A linear array of photodiodes responds to light passing through the fluid by registering a series of signals representing the linear projection of particles passing through the plane defined by the light source and the photodiode array. The fluid is supplied from a reservoir which can be selectively pressurized by a gas to control the egress flow rate of fluid. A syringe serves as the egress path from the reservoir and a rotatable stirring rod is disposed in the syringe to stir the egressing fluid. The syringe feeds a disposable assembly which includes a hypodermic needle feeding the capillary tube which is mounted between a microscope slide and cover in the path of the sensing light.

Abstract: An improved cuvette array for a centrifugal analyzer is disclosed. The array is conventionally formed from upper and lower discs of flexible thermoplastic material, in which the lower disc is formed with a plurality of compartments circumferentially spaced about a first central hub, and the upper disc is bonded to the outer periphery of the lower disc and closes an outer peripheral portion of the compartments. The array is improved by forming the upper disc with a central portion that includes a second central hub positioned above the first central hub, together with an intermediate web that bridges the second central hub to the outer peripheral portion of the upper disc so as to close off the inner peripheral portion of the compartments. The intermediate web portion may be joined to the outer peripheral portion of the upper disc by a tearible score line to permit the central portion of the upper disc to be entirely removed.

Abstract: In an instrument for optically analyzing particulate samples such as grain samples, the sample is introduced into a chute which is received in a vibrating apparatus to vibrate the grain in the chute and compact it. The chute is then dropped to a carriage which transports the chute and the grain through a beam of narrow band infrared light. A photocell is positioned to detect the amount of light passing through the grain sample.

Abstract: In accordance with the present invention, apparatus for photometric light absorption measurements of liquid samples contained in reaction cuvettes comprises a temperature controlled bath unit in which at least one light path conversion means is immersed in the fluid bath medium and is provided with at least two layers, one light-reflective layer and one non-corrosive layer on a surface thereof.

Abstract: Apparatus and method for biological fluid analysis involving radiation measurement. The apparatus includes a pipetting dispenser having means for directing radiation from the piston thereof generally axially through the liquid in the pipette tube such that the pipetting dispenser serves not only as a means for measuring and mixing liquids, but also serves as a cuvette. The apparatus and method provide maximum radiation path length to accommodate liquids of different optical density. Still another feature of the apparatus and method is the provision of means for removing liquid from the outer surface of a pipette tube, which means are readily adapted to automated procedures. The apparatus in one embodiment is adapted for absorbance measurement of analyte samples, and in another embodiment is adapted for measurement of fluorescent radiation from analyte samples.

Abstract: An apparatus for detecting photoelectrically a particle agglutination pattern formed on a conical bottom surface of a reaction vessel is disclosed. A lamp and a diffusion plate are arranged above the reaction vessel to illuminate the particle pattern and an objective lens and a light detector are arranged underneath the reaction vessel to form an image of the particle pattern on the light detector. In order to prevent a relatively sharp image of the diffusion plate from being formed on the light detector, an optical correction plate having a conical projection formed in its lower surface is arranged immediately below the reaction vessel. The optical correction plate may be secured to a lower surface of the reaction vessel or may be integrally formed with the reaction vessel on its lower surface.