Tobacco sorting method and apparatus

• US 4,609,108 A
• Filed: 01/27/1984
• Issued: 09/02/1986
• Est. Priority Date: 01/27/1984
• Status: Expired due to Fees

• Current Assignee: Institute PO Technicheska Kibernetica I Robotika
• Original Assignee: Institute PO Technicheska Kibernetica I Robotika
• Inventors: Ribarov, Hristo M., Markov, Spas N., Hristozov, Vladislav N., Marchev, Zdravko B., Valev, Atanas A.
• Primary Examiner(s): Reese, Randolph A.
• Assistant Examiner(s): Hajec, Donald T.
• Application Number:
  US06/574,705
• Time in Patent Office: 949 Days
• Field of Search: 209/576, 209/577, 209/580, 209/581, 209/582, 209/587, 209/639, 209/644, 209/557, 209/905, 209/906, 198/493, 198/453, 198/689, 271/121, 271/197, 271/199, 271/309
• US Class Current: 209/581
• CPC Class Codes: A24B 1/04 Sifting, sorting, cleaning or removing impurities from tobacco
• CPC Class Codes: B07C 5/342 according to optical properties, e.g. colour according to radiation transmittivity B07C5/3416
• CPC Class Codes: B07C 5/366 during free fall of the articles
• CPC Class Codes: Y10S 209/905 Feeder conveyor holding item by suction
• CPC Class Codes: Y10S 209/906 Pneumatic or liquid stream feeding item

Abstract

Method of and apparatus for sorting tobacco into two groups: a group of satisfactory leaves and a group of unsatisfactory leaves. Tobacco leaves, spaced so that they pass one by one along a conveyor, travel through a zone illuminated by pulsed polychromatic light and an optical sensor receiving light reflected from the tobacco leaves. In a manner which is synchronous with the pulsations of light there is measured the quantity of the light reflected by each of the leaves in the green, orange, red, and infrared areas of the spectrum. Sums are formed from the values corresponding to the reflected light in such areas of the spectrum and relations are obtained between sums corresponding to the green and orange as well as to the red and infrared ranges, of time in which the value of the reflected light in the infrared area is greater than a value preliminarily preset by the operator. When in such time a number of measurements greater than the preset value is reached or when the relations of the sums are outside preset limits, a decision is made to eliminate the leaves which give rise to such measurements. The apparatus eliminates all but a single layer of longitudinally spaced tobacco leaves thereon, and removes the leaves from the conveyor and blows them in virtually free travel through the air to a sorter in the form of a pneumatic unit.

Claims

1. Apparatus for sorting tobacco leaves, comprising a perforated belt conveyor, means providing a zone of sub-atmospheric pressure beneath the upper run of said conveyor belt, a source of polychromatic light illuminating a zone of vision through which tobacco leaves travel in sequence, said source emitting light, which varies its intensity periodically due to supplying said source with low frequency alternating current and having green, orange, red, and infrared areas of the spectrum, and an optical sensor receiving light reflected to the sensor from the tobacco leaves, a pneumatic unit which separates in a zone of action the successive tobacco leaves which have thus been inspected by the light source and the optical sensor to divide such tobacco leaves into a satisfactory group and an unsatisfactory group, between the zone of vision of the optical sensor and the zone of action of the pneumatic unit there is a distance insuring the entering of the tobacco leaf in the zone of action of the pneumatic unit after the value of the light reflected in the infrared range has diminished to a value below the preliminary preset value, between the vision zone of the optical sensor and the zone of action of the pneumatic unit there is disposed a flexible screen, between the discharge end of the conveyor belt and the zone of vision of the optical sensor there is disposed a first air jet which is oriented in the direction of movement of the upper run of the conveyor belt and a second jet disposed above the upper run of the conveyor belt, said second jet being oriented in a direction opposite to the upper run of the conveyor belt, the two jets being connected via a flow stabilizer to a source of super-atmospheric air pressure.

2. Apparatus according to claim 1, wherein upstream of the second jet, which is directed contrary to the direction of movement of the upper portion of the conveyor belt, there is disposed a porous walled container for temporarily receiving and holding tobacco leaves which are blown from the conveyor belt, whereby leaves are deposited upon and travel with the conveyor as a single layer of spaced individual tobacco leaves.