Optical paper sorting method device and apparatus
AssigneeEco-Shred Ltd.
InventorsZaheer Khalfan, Sheldon Greenspan
Life of this patent
Estimating the term…
Abstract
An optical paper sorting system uses diffuse reflectance to identify a sheet of paper, conveyed on a conveyor, as either white or groundwood grade. A light source illuminates a sheet of paper and an optical collection system collects and filters the light diffusely reflected from the sheet of paper. The reflected light strikes a detector which produces a photoelectric current proportional to the intensity of the filtered light in a specific region in the electromagnetic spectrum, preferably ultraviolet. The signal from the detector may be digitized and processed by a computer which classifies the sheet as either white or groundwood, and activates an ejection device to produce an air blast for diverting whichever grade is selected for ejection.
Claims8
An apparatus for separating a material containing less than a selected amount of lignin from a material containing more than the selected amount of lignin, the materials being of the same color or of a different color, comprising
- a conveyor for conveying the material to a collection bin,
- a detection device disposed adjacent to the conveyor, comprising a light source positioned to emit light comprising an ultraviolet component to strike the material, a detector for detecting ultraviolet light and generating an electrical signal proportional to an intensity of detected ultraviolet light, the detector being positioned to detect ultraviolet light diffusely reflected off of the material, an optical filter disposed between the material and the detector to eliminate components of diffusely reflected light outside of the ultraviolet range, and an instrument for measuring a level of the electrical signal,
- a comparing device for comparing the level of the electrical signal to a reference level to determine whether the material contains less than or more than the selected amount of lignin, and
- an ejection device disposed downstream of the detection device, for receiving an ejection signal from the comparing device when the material contains more than or less than the selected amount of lignin and ejecting the material in response.
Dependencies are inferred from the claim text.