Pacific Scientific Company

Pacific Scientific Instruments Company

Neotec Corporation

Nirsystems Incorporated

Foss Nirsystems, Inc.

Donald R Webster

Eugene R Ganssle

In an infrared analysis instrument, a fiber optic probe, designed to be inserted into a particulate sample, is formed from distal ends of transmitting and receiving optic fibers. The distal ends of the transmitting fibers are located centrally in the probe and the distal ends of the receiving fibers are formed in a ring around the distal ends of the transmitting fibers. The distal ends of the receiving fibers are set back from the distal ends of the transmitting fibers. The receiving fibers carrying diffusely scattered light reflected from and transmitted through the particulate sample to a spectrophotometer housing containing fixed grating and an array of silicon photodetectors arranged to detect the spectrum dispersed by the grating in the range of 500 to 1100 nm.

Infrared analysis instrument with offset probe for particulate sample

In a spectrophotometer, a light source is provided in the form of a multiplicity of light emitting diodes which transmit light through an entrance slit to irradiate an oscillating grating. The light is dispersed by the grating toward an exit slit which transmits a narrow bandwidth of light to irradiate a sample. As the grating oscillates, the wavelength transmitted through the exit slit is scanned through a selected spectrum. The diodes in the array each emit light in a different wavelength band so that the diodes as a group emit light throughout the selected spectrum. As the grating oscillates, the diodes are energized and extinguished in sequence so that no more than two diodes will be energized at any given instant of time and the energized diode will be emitting light at the wavelength dispersed by the grating to the exit slit.

Spectrophotometer with light source in the form of a light emitting

In an optical instrument, fiber optics are employed to receive light from a linear filament. The fiber optics are arranged into a plurality of light receiving bundle ends distributed around the linear filament and shaped into narrow rectangular slits aligned with the filament. The fibers from each of the receiving ends are equally distributed between two transmitting ends which direct the light through cylindrical lenses to opposite sides of a rotating filter wheel in a paddle wheel configuration. Light beams from the transmitting ends of the fiber optic bundles pass through filters on the filter wheel to additional fiber optic bundles which carry the received light to a probe.

Optical instrument employing fiber optics to direct light through

An optical analysis system employs a rectangular beam of light passing through interference filters to analyze the constituents of a test sample moving through the beam. A plurality of interference filters are moved successively through the beam between the source of the beam and the sample and are tilted about an axis as they are moved, thereby transmitting a range of wavelengths to the sample. Skew rays of light in the beam strike the filters at different angles from the angles at which rays parallel to the axis of the beam strike the filters and so transmit wavelengths different from those of rays parallel to the axis of the beam. The angle deviation is greatest for the skew light rays which are skewed from the axis of the beam in a plane perpendicular to the tilt axis of the filters. Thus, the shorter dimension of the rectangular beam is arranged to be perpendicular to the tilt axis of the filters.

Rectangular impinging beam

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.

Particulate sample analyzing instrument employing vibration to compact

In an instrument adapted particularly for analyzing agricultural products, such as grain, interference filters are rotated successively through an infrared wide wavelength band beam of light, which irradiates a sample of the product. Each of the interference filters operates to transmit a narrow wavelength band of light, the center frequency of which is scanned through a range of values as the angle of incidence of the beam of light to the interference filter varies as the filter rotates through the beam of light. An optical track is provided which rotates with the assembly of interference filters to generate pulses from index markings in the optical track. The markings in the optical track are spaced so that one pulse is generated for each angstrom of variation of the center frequency transmitted through an interference filter. The pulses are counted in the counter and the counts in the counter are used to control the selection of intensities reflected from the sample to be used in the analysis of the sample.

Optical analyzing instrument with equal wavelength increment indexing

An instrument for optically measuring and analyzing samples of particulate material includes a chute for conveying the samples through a light beam by which the measurements are made and a trough positioned at the bottom of the chute. The trough supports a column of the particulate material in the chute and acts as a gate to prevent the particulate material from flowing out of the chute. The trough is mounted on a vibrator and during the measurement operation vibrates to cause the particulate material to flow out of the chute. When vibrating, the trough transmits vibrations up through the column of particulate material in the chute to maintain the column in a free flowing condition and to prevent bridging.

Optical analyzing instrument having vibrating trough

In an instrument for optically measuring the constituents of grain samples, a grinder is provided to grind a sample of grain and direct the ground grain into a chute. A hopper is provided for loading the grain into the grinder with a gate for controlling the flow of the grain into the grinder. A filter wheel and infrared light source assembly directs a beam of infrared light on the grain sample in the chute while continuously changing the wavelength irradiating the grain. As the infrared light is irradiating grain, the grain is moved in a bed through the infrared light and reflectivity measurements are made. From these reflectivity measurements, the oil, water and protein content of the grain sample is determined.

Instrument for grinding and analyzing material in ground state

An improved grain quality analyzer, for analyzing the percentage concentration of various constituents, e.g. protein and water, in a grain sample, photo-optically measures the change in the optical density of the sample, .DELTA. OD, in a range of characteristic wavelengths and, for protein, in a range of neutral wavelengths and uses these measured values to compute the percentage concentration of the constituents. A grain sample is irradiated with light, the wavelength of which sweeps across the infrared light-spectrum including a range of wavelengths termed characteristic wavelengths, and, for protein, a range of wavelengths termed neutral wavelengths. The characteristic wavelengths are those wavelengths at which the optical characteristics of the irradiated sample, that is, the optical density, reflectivity, transmissivity, and/or absorption, are known to vary as a function of the concentration of the measured constituent, and, for the protein measurement, the neutral wavelengths are those wavelengths at which the optical characteristics are substantially independent of the concentration of the protein. In the preferred embodiment, photo-optical sensors measure the light reflected from the sample and provide output signals indicative of the optical density of the sample as a function of the wavelength of the irradiating light. Control and computing means sample the sensor output at spaced apart points in the range of characteristic wavelengths and in the range of neutral wavelengths to provide signals representative of the optical characteristics of the sample. Computing circuitry computes the percentage concentration of water and, for protein, computes the percentage concentration using an algorithm in accordance with the present invention which eliminates the inaccuracies introduced by light scattering from the sample.

Grain quality analyzer

An automatic test instrument for gaging the percentage of various constituents in organic substances by comparing the reflective optical density of the subject at various wavelengths. Narrow band optical filters are connected together in the form of a rotatable paddle wheel positioned so that the filters can be individually swept through the incident light path between the specimen and wideband light source. As the filter wheel turns, the band of light passed by each filter is progressively shifted with the changing angle of the filter relative to the light path. The filter wheel configuration includes opaque vanes extending from the ends of the filters to periodically interrupt the passage of light to the specimen. Photocells are positioned to sense the level of light reflected from the specimen. The output of the photocells is sampled at pedetermined times relative to the rotation of the filter wheel to yield values indicative of reflected intensity at certain wavelengths. Using these values, an electronic circuit in one embodiment calculates three optical density difference values corresponding to moisture, protein and oil content of the specimen. The difference values are automatically inserted in three linear equations which are solved to obtain readings representing the true percentages of oil, water and protein contained in the specimen. Each time a new specimen is loaded for testing, the instrument is automatically calibrated against a standard sample, preferably Teflon (Trademark). The output of the photocells is amplified in a special circuit which subtracts the level of dark period current from the output when the photocells are illuminated.

Optical analyzer for agricultural products

An automatic test instrument for gaging the percentage of various constituents in organic substances by comparing the reflective optical density of the subject at various wavelengths. Narrow band optical filters are connected together in the form of a rotatable paddle wheel positioned so that the filters can be individually swept through the incident light path between the specimen and wideband light source. As the filter wheel turns, the band of light passed by each filter is progressively shifted with the changing angle of the filter relative to the light path. The filter wheel configuration includes opaque vanes extending from the ends of the filters to periodically interrupt the passage of light to the specimen. Photocells are positioned to sense the level of light reflected from the specimen. The output of the photocells is sampled at predetermined times relative to the rotation of the filter wheel to yield values indicative of reflected intensity at certain wavelengths. Using these values, an electronic circuit in one embodiment calculates three optical density difference values corresponding to moisture, protein and oil content of the specimen. The difference values are automatically inserted in three linear equations which are solved to obtain readings representing the true percentages of oil, water and protein contained in the specimen. Each time a new specimen is loaded for testing, the instrument is automatically calibrated against a standard sample, preferably Teflon (Trademark). The output of the photocells is amplified in a special circuit which subtracts the level of dark period current from the output when the photocells are illuminated.

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Laurel, MD, United States of America

Donald R Webster