Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
  • G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
  • G01N21/25—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N15/00—Investigating characteristics of particles; Investigating permeability, pore-volume or surface-area of porous materials
  • G01N15/02—Investigating particle size or size distribution
  • G01N15/0205—Investigating particle size or size distribution by optical means
  • G01N15/0227—Investigating particle size or size distribution by optical means using imaging; using holography
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
  • G01N21/84—Systems specially adapted for particular applications
  • G01N21/85—Investigating moving fluids or granular solids
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
  • G01N33/0091—Powders
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
  • G01N33/02—Food
  • G01N33/10—Starch-containing substances, e.g. dough

Definitions

• the present invention relates to an apparatus for analyzing the characteristics of ground products, and in particular an apparatus which can be used for carrying out the analysis of the colorimetry, as well as of the size and the purity, if desired, of particles of products coming from grinding plants, such as for instance flours and brans of different kinds.
• Apparatuses for analyzing ground products are known to comprise a camera which shoots a portion of ground product dropped in front of its lens. Said camera is connected to a computer which analyzes the image sequence received from the camera and supplies, according to the content of these images, the particle colorimetry and size. During their fall, the particles of ground product are illuminated by one or more light sources arranged on the same side of the camera, so that the particles are illuminated frontally and appear as bright points on a background which must be black and opaque, in order to show up the particles and avoid light glares.
• the background becomes progressively light since some particles settle thereon during the time. Being light, the particles decrease the contrast of the background, thereby altering the values of the particle colorimetry and size measurement. These particles are very fine, so that they cannot be easily removed from the background with air jets and therefore brushes or other devices difficult to employ must be used.
• the camera used for the colorimetric analysis is the same used for the particle size analysis, so that its color reproduction does not have a stability suitable for a precise analysis of the particle colorimetry. It is therefore an object of the present invention to provide an apparatus for analyzing ground products, which is free from the above mentioned drawbacks. Said object is achieved with an apparatus, the main features of which are described in the first claim and other features are described in the following claims.
• the apparatus allows to carry out precise colorimetric analysis on a uniform particle layer which constitutes a significant sample of all the particles to be analyzed.
• Said colorimeter preferably comprises a spectrophotometer, so as to improve the measurement precision and detect impurities which can be detected only with fluorescence analysis and not with colorimetric analysis, such as the impurities containing high ratios of ferulic acid.
• the images of the particles are transmitted to the colorimeter by optical gathering means preferably comprising a hollow sphere provided with a hole through which these images are projected from the outside, the interior of said hollow sphere being coated by a paint suitable for reflecting the entire light spectrum.
• said images are preferably concentrated into the hole of the hollow sphere by an achromatic doublet.
• the particles of ground product transported by the vibrating chute with the transparent bottom can be dropped in front of the lens of a camera connected to a computer which analyzes the image sequence received from the camera and supplies, according to the content of these images, the particle size.
• the apparatus according to the present invention can precisely analyze not only the particle colorimetry, but also their size, thereby exploiting for these purposes some common parts of the apparatus itself, so as to reduce the hindrance and the manufacturing costs with respect to two distinct apparatuses.
• means for deviate the shooting axis of said camera toward the transparent bottom of the vibrating chute can be arranged along the shooting axis.
• the apparatus comprises in a known way a camera 1 suitable for shooting a portion of particles 2 of ground product which are dropped in front of its lens 3.
• the latter is arranged with the shooting axis 4 oriented in a substantially perpendicular way with respect to the plane 5 (indicated with a hatched line) along which particles 2 fall.
• Camera 1 is further connected in a known way to a computer (not shown in the figure) which analyzes the sequence of images received and supplies, thanks to a suitable program which can be of a known kind, the size of particles 2 according to the content of these images.
• particles 2 are illuminated by one or more light sources 6, 6' which are arranged transversally, in particular laterally, with respect to the fall plane 5 of particles 2.
• the light sources 6, 6' preferably comprise two series of high efficiency LEDs, which are suitable for emitting flashes synchronized with the image sampling period of camera 1, in order to illuminate particles 2 only when these, are effectively shot, for instance with a frequency of 10 images per second, so that the LEDs cannot overheat.
• the light beams emitted by the light sources 6, 6' are preferably collimated along the fall plane 5 of particles 2 thanks to reflecting or refracting means 7, 7', such as for example mirrors, prisms and/or lenses.
• these reflecting or refracting means 7, T are made up of a pair of hemicylindrical lenses arranged with the longitudinal axis substantially parallel to the light sources 6, 6' and with the hemicylindrical surface turned toward the latter.
• the fall plane 5 of particles 2 is therefore comprised in a substantially perpendicular manner between the rectangular surfaces of the hemicylindrical lenses 7, 7'.
• the width of the light beams emitted by the light sources 6, 6' is preferably less than the depth of field of lens 3 of camera 1, so that particles 2, when they are illuminated by the light sources 6, 6', are always focused by lens 3.
• the light beams are collimated by the hemicylindrical lenses 7, T within a space comprised between two vertical planes which are 10 mm away from each other, while lens 3 has a greater depth of field. As a matter of fact, it has been verified that nearly all the particles 2 fall within said space 10 mm wide. Particles 2 are transported toward the fall plane 5 by a chute 8 which vibrates with a high intensity.
• Another chute 9 which vibrates with a lower intensity with respect to chute 8 and leads above the latter, transports in the meantime a determinate quantity of particles 2 taken by a feeding duct 10 having the lower end arranged near to the bottom 11 of the vibrating chute 9.
• this bottom is transparent and its upper and lower surfaces are smooth, so that particles 2 can homogeneously spread above it and can be shot from the bottom without distortions.
• Mobile reflecting or refracting means 12 suitable for deviating the shooting axis 4 toward the transparent bottom 11 of vibrating chute 9, preferably in the direction of feeding duct 10, are arranged along the shooting axis 4 of camera 1.
• the mobile reflecting or refracting means 12 comprise a mirror, for example inclined about 45°, which is arranged under the vibrating chute 9 and is fixed to a rod 13 which can translate along a substantially horizontal axis perpendicular to the shooting axis 4.
• one or more light sources 14, 14' are arranged under the vibrating chute 9 for illuminating the lower surface of its bottom 11.
• the light sources 14, 14' preferably comprise two series of high efficiency LEDs, if necessary of a different kind with respect to the light sources 6, 6', which can emit flashes synchronized with the image sampling period of camera 1.
• the computer connected to camera 1 analyzes the sequence of received images, detects the particles 2 having a dark color and provides, thanks to a suitable program also of a known kind, data relating to the purity of particles 2 according to the number of dark particles detected. Since the particle size measurement needs long times, camera 1 can shoot the transparent bottom 11 of the vibrating chute 9 for a period shorter than the period in which it shoots the particles 2 falling from the vibrating chute 8. For example, these shooting periods of camera 1 can last 1 and 20 seconds, respectively.
• the apparatus suitably comprises a colorimeter 15, preferably a spectrophotometer, which is connected through an optical fiber 16 to optical gathering means 17 comprising a hollow sphere, the interior of which is coated by a white paint suitable for reflecting the entire light spectrum, so as to uniformly spread it by means of its numerous reflections.
• the hollow sphere 17 is provided with a hole through which the images of the particles 2 laying on the transparent bottom 11 of the vibrating chute 9 are projected from the outside. Before reaching the interior of the hollow sphere 17, these images are in fact reflected by a mirror 18, which is arranged under the transparent bottom 11 correspondingly to duct 10 and is inclined about 45°, after which they are concentrated into the hole of the hollow sphere 17 by an achromatic doublet 19.
• the light sources 14, 14' also comprise blue and ultraviolet lamps, while the transparent bottom 11 is made of quartz, so as to allow the passage of the exciting radiation.

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• Chemical & Material Sciences (AREA)
• Life Sciences & Earth Sciences (AREA)
• Physics & Mathematics (AREA)
• Health & Medical Sciences (AREA)
• General Physics & Mathematics (AREA)
• Analytical Chemistry (AREA)
• Biochemistry (AREA)
• General Health & Medical Sciences (AREA)
• Immunology (AREA)
• Pathology (AREA)
• Dispersion Chemistry (AREA)
• Spectroscopy & Molecular Physics (AREA)
• Engineering & Computer Science (AREA)
• Food Science & Technology (AREA)
• Medicinal Chemistry (AREA)
• Investigating Or Analysing Materials By Optical Means (AREA)

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• 2000
  • 2000-11-28 EP EP00985761A patent/EP1337833A1/de not_active Withdrawn
  • 2000-11-28 WO PCT/IT2000/000481 patent/WO2002044692A1/en active Application Filing

Patent Citations (4)

Non-Patent Citations (1)

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