Classifying – separating – and assorting solids – Sorting special items – and certain methods and apparatus for... – Condition responsive means controls separating means
Reexamination Certificate
1999-09-03
2001-06-26
Walsh, Donald P. (Department: 3653)
Classifying, separating, and assorting solids
Sorting special items, and certain methods and apparatus for...
Condition responsive means controls separating means
C209S509000, C209S581000, C209S582000, C209S587000
Reexamination Certificate
active
06252188
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a color sorting apparatus for agricultural products capable of sorting products based on optically sensed characteristics using a light source with visible light spectra or a near-infrared (“near-IR”) spectra.
2. Description of the Prior Art
Commonly owned U.S. Pat. No. 4,454,029, of which Applicant Codding is a named inventor, relates to a bichromatic sorter for agricultural products. These sorters have been primarily used to detect unacceptable agricultural products based on color of the product, such as coffee beans, peanuts and the like. There were certain types of relatively smaller, usually granular, agricultural products, such as rice grains, which required only monochromatic or gray level to sort to reject unacceptable products. Although the '029 sorter is capable of sorting products using two color illumination levels, the sorter employs only a visible spectrum illumination source. Some products cannot be sorted using normally visible light buy may be differentiated using light in the near-IR range. For instance, tree nuts, such as almonds, require a lower frequency light to distinguish between acceptable and unacceptable products. Lower frequency light is also useful in distinguishing between agricultural products and foreign materials, such as stems, glass and plastics, which are often inadvertently included with the products during harvest or subsequent processing.
Commonly owned U.S. Pat. No. 4,697,709, of which Applicant Codding is a named inventor, describes a monochromatic sorting apparatus having a plurality of optical stations. Each station is composed of a plurality of optical sensors which are capable of sensing light reflected from a stream of product. The stream is illuminated by fluorescent lamps. The apparatus is capable of using only one source of illumination (e.g. fluorescent) and is therefore not capable of sorting products which require differentiation based on their near-IR spectra.
U.S. Pat. No. 4,466,544 relates to a sorting apparatus having a plurality of movable filters which can be remotely actuated such that a specific filter may be selected for use depending on the nature of the product being sorted. This eliminates the need to physically remove and replace filters each time the product being sorted is changed, thereby making the apparatus more economical and efficient. However, the apparatus is designed to operate with only one type of light source, thereby limiting its capabilities to sorting only those products which can be differentiated using a light source of only a single spectra (e.g. visible light).
U.S. Pat. No. 5,779,058 involves a color sorting apparatus for grains. This type of sorter has an illumination device for illuminating the grain, and an optical detector with an optical detection section for receiving the light from the illuminated grain. The illumination device employs a source having spectral energy distribution in both the visible light region and the near infrared region. The optical detection section of the optical detection device includes a first light receiving sensor having a high sensitivity to the visible light region and a second light receiving sensor having a high sensitivity to the near infrared region. While this apparatus is intended to be capable of sorting products using both the visible spectra and the near-IR spectra, it was more complex and expensive than a machine having a single type of sensor and illumination source. In addition, the '058 apparatus uses a halogen light source to generate the near-IR illumination. Halogen light has typically required a greater number of bulbs to provide requisite illumination, as well as consumed significantly more power. The power consumed generated a great deal of undesirable heat, as compared to, for instance, an incandescent or fluorescent bulb.
SUMMARY OF THE INVENTION
The present invention provides a sorter capable of sorting agricultural products using interchangeably either an visible light source or a near-IR light source. By interchangeably using two different light sources, the present invention can efficiently and economically sort a much greater variety of products than those machines described in the prior art. The products are formed into a number of parallel, downwardly falling streams and are sorted based on their illumination intensity as they fall in streams past an illuminated viewing chamber. A suitable number of optical scanning stations, equal to the number of falling streams of product, are located in the viewing chamber. The streams of product are illuminated in the viewing chamber by the selected source of light and the amount of light reflected by the streams of falling product is sensed. Detected unacceptable products and undesirable foreign materials are then rejected.
Preferably, the sorter uses one of two available illumination sources. The first source is a visible light source. The viewing chamber has power providing connection receptacles having a set of mounting points, which include electrical contacts, located hear the falling stream of produce and other objects. Typically, the visible light source is a fluorescent bulb, such as those commonly used in home or commercial lighting fixtures and the mounting points include sockets capable of accepting such bulbs. Any desired number of these bulbs can be used, depending on the nature of the specific application, preferably however, two or four such bulbs are used.
The second illumination source provided for use with the present invention is a near-IR light source. The second source is mounted in a second set of mounting points, also located inside the cabinet, each containing an electrical connector. With the present invention, the mounting points for the second source are accessible for use with the second source but do not interfere with insertion and use of the first light source with it is desired for use. Conversely, the mounting points for the first light source are accessible for connection to that source without interference with access or use of the second light source where its use is required. Therefore, only one type of light source need be present in the cabinet at a time. Typically, an incandescent bulb is used to generate near-IR spectra and the mounting points include sockets capable of accepting such bulbs. It has been found that the incandescent bulb is capable of emitting a near-IR spectrum at a fraction of its rated voltage. Thus, the sorter is able to use less power, generate less heat. Further, at suitable intensity levels for product flow detection and for sensing unwanted debris particles, the service life of the incandescent bulbs is greatly extended.
The sorter according to the present invention is designed to operate with either a first light source in place or a second light source in place. Due to the location of the mounting points, the viewing chamber will typically not accommodate both the fluorescent bulbs and the incandescent bulbs at the same time.
Each light source has a dedicated power supply. For instance, the visible light source will require a high frequency ballast-type power supply, whereas the incandescent
ear-IR source may require a direct-current power supply. The power supplies may be selectively energized, such that only one is in use at any given time. For instance, when a fluorescent bulb is being used, only the high voltage alternating current ballast power supply is providing power. In this way, the light source can be switched based on sorting requirements relatively easily without the need to install and remove the power supply as well.
REFERENCES:
patent: 3980181 (1976-09-01), Hoover
patent: 4134498 (1979-01-01), Jones
patent: 4308959 (1982-01-01), Hoover
patent: 4454029 (1984-06-01), Codding
patent: 4466544 (1984-08-01), Satake et al.
patent: 4697709 (1987-10-01), Codding
patent: 4878582 (1989-11-01), Codding
patent: 4940850 (1990-07-01), Satake
patent: 5179474 (1993-01-01), Bailey
patent: 5193782 (1993-03-01), Bailey
patent: 51
Codding Elias H.
Zapata Donald F.
Bracewell & Patterson L.L.P.
Delta Technology Corporation
Miller Jonathan R
Walsh Donald P.
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