The recycling industry sorts and separates reusable materials out of collected materials. The sorted and separated reusable materials are reprocessed into raw materials in other applications while the unusable material is typically sent to a landfill. Machines, called sorters, are often used to mechanically sort and separate a variety of types of materials from a material stream. Such machines typically use a variety of methods to move the material stream including conveyors to mechanically move the material stream or sloping chutes to move the material stream by gravity. The material stream is passed through the detection range of any of a variety of sensors that detect metals, plastics, glass, or other parameters like size and color that can be sorted and separated from the material stream.
A method and system of sorting materials from a material stream on a sorter is provided. The material stream includes a plurality of components and the sorter is able to detect and sort at least one component of the material stream. The sorter includes a first detection zone and an adjacent second detection zone on the sorter. Each detection zone sorts at least one component from the material stream. The material stream is introduced to the first detection zone of the sorter. The sorter substantially sorts at least one component from the material stream in the first detection zone by removing at least one component of the material stream from the sorter. The remaining material stream is returned to the second detection zone of the sorter where it is substantially sorted a second time by removing at least one component of the remaining material stream from the sorter.
The sorter may have more than two detection zones, in which case portions of the material stream are returned to the sorter for processing within each detection zone based on the material detector system readings for that zone. If desired, the material stream may be returned by a series of conveyors that collect and transfer portions of the sorted material stream back to the sorter. Alternatively the material stream may be returned by a collection of bins that are manually transferred to the appropriate detection zone for further processing. Other material handling systems are also possible.
Those skilled in the art will realize that this invention is capable of embodiments that are different from those shown and that details of the devices and methods can be changed in various manners without departing from the scope of this invention. Accordingly, the drawings and descriptions are to be regarded as including such equivalent embodiments as do not depart from the spirit and scope of this invention.
For a more complete understanding and appreciation of this invention, and its many advantages, reference will be made to the following detailed description taken in conjunction with the accompanying drawings.
Referring to the drawings, some of the reference numerals are used to designate the same or corresponding parts through several of the embodiments and figures shown and described. Corresponding parts are denoted in different embodiments with the addition of lowercase letters. Variations of corresponding parts in form or function that are depicted in the figures are described. It will be understood that variations in the embodiments can generally be interchanged without deviating from the invention.
The sensors 40 are connected to the sorting system 20 (described in more detail below). Each control module 38 is adjustable to detect a certain component of the material stream therefore a system comprising seven control modules 38 could define up to seven adjacent detection zones. Each detection zone delineates a portion of the width of the material handling system 12. In this embodiment, the sensors are located along the lines that define the first detection zone 22 and the second detection zone 24 with the first four control modules 38 defining the first detection zone 22 and the last three control modules 38 defining the second detection zone 24. Each detection zone can be physically separated by dividers (not shown) to keep the material streams in each detection zone from mixing on the material handling system 14 and/or the material introduction system 12. The embodiment described above is not limited to metal detection systems that comprise modular control systems. Sorters that have detection systems with a single Programmable Logic Controller (PLC) that controls all of the sensors across the width of the material handling system can be programmed to define detection zones as described above.
The sorting system 20 of the sorter machine 10 shown comprises a series of paddles 42 that are each controlled by a single sensor 40. Each paddle 42 is about two inches wide. Therefore each control module 38 can define a detection zone of about twelve inches wide. In this embodiment, the first detection zone 22 is about four feet wide and the second detection zone 24 is about two feet eight inches wide. The material detector system and the sorting system 20 are controlled by the control system 26.
The sorter machine 10 is often used as a step in sorting materials in a material stream that has already been somewhat processed to remove the largest and smallest materials. So the material stream that this sorter machine 10 handles is typically about ½ inch to 2 feet wide, but the method described herein is easily applicable to any sized material stream so long as the sorter machine 10 is able to process the material. The sensors 40 on the ProSort machine are typically inductive sensors that can distinguish metals from non-metals in one zone and stainless steel from other metals in a second zone. But any other kinds of sensors detecting any other kinds of materials can be used.
A conveyor 28 from an upstream process introduces the material stream to the sorter machine 10 at the material introduction system 12. The material stream is deposited at about the first end 16 of the sorter machine 10 on the material handling system 14 in such a way as to substantially limit the material stream to the first detection zone 22. The material stream passes through the detection range of the material detector system as it is conveyed from the first end 16 to the second end 18. When a sensor 40 of the material detector system detects a target component in the material stream, the control system 26 either sends a timed signal to the corresponding paddle 42 in the sorter system 20 to deflect the material or does nothing and lets the material drop past the paddles 42 as required by the current configuration of the sorter machine 10.
Although many sorters that have detection systems are able to distinguish more than one kind of material from a materials stream, they are unable to distinguish more than one kind of material at the same time. For example, some sorting machines incorporating material detectors that have inductive sensors can distinguish 1) all metals from a materials stream and 2) stainless steel from other metals, but are not equipped to be able to sort both stainless steel and other metals from a materials stream at the same time. To work around this problem, the material stream is processed twice through the sorter, with a first pass to sort out all the metals from the material stream and a second, or re-pass, to sort out the stainless steel from the metals. This solution requires the sorters to operate in a batch mode, i.e. the materials stream is completely processed before it is re-passed through the system. This is a bottleneck in the system that adds to operating expense. Another solution is to use two sorters in series, with the first sorter to remove all metals from the material stream and the second sorter to remove any stainless steel from the sorted metals. However this requires the expenditure to purchase, install, and operate two machines and takes up valuable floor space.
In contrast, the embodiment depicted in
This example allows sorters to be able to recover different products of a higher grade from a material stream and provide an additional income source for operators of such sorters. Some of the embodiments described herein can also be retro-fitted to existing sorters to be able to process multiple materials streams in multiple sorting zones and allow current operators to recover a higher grade of product from the same material stream without having to purchase additional sorters.
The collection areas for the sorter system 20 can be collection bins as with the first collection system 32 or conveyor belts as with the second and third collection systems 34 and 36. The material return system 30 can be a system of conveyor belts as shown in
The size of the first and second detection zones 22 and 24 can be adjusted based on the expected composition of the material stream. For example if the facility that the sorter machine 10 is installed in expects a material stream that is known to have little or no stainless steel, the first detection zone 22 can be increased in size to cover a greater width of the material handling system 14. The second detection zone 24 would be correspondingly shortened. In this case the location and size of the material return system 30 and the collection systems 32, 34, and 36 would have to be appropriately adjusted to accommodate the change in size of the first and second detection zones 22 and 24.
It is also possible for the second detection zone 24 to be configured to detect the same component in the material stream as the first detection zone 22. In this scenario, either the material stream or the separated component of the material stream that has been sorted through the first detection zone 22 is returned to the second detection zone 24 and processed a second time to further remove any residual material not successfully separated the first time. This provides a higher capture of a target component or a more thorough removal of a target component from a material stream.
It is also possible to define more detection zones than the two depicted in
There are many types of sorters that separate recyclable materials from material streams using a variety of technologies. While the detection system described in
The sorter is not limited to the sorter system depicted in
The material handling system is not limited to a conveyor belt as depicted in
The sorter is not limited to metals as described in the example above. Any kind of detectable parameter may be used to sort a material stream. The sensors can be configured to detect metal, plastics, glass, the size of the material in the material stream, the color of the material in the material stream, or other detectable parameter as required by the particular application.
Some sorters can sort more than one type of material from a material stream.
This invention has been described with reference to several preferred embodiments. Many modifications and alterations will occur to others upon reading and understanding the preceding specification. It is intended that the invention be construed as including all such alterations and modifications in so far as they come within the scope of the appended claims or the equivalents of these claims.
This application takes priority from U.S. provisional application 60/912,247 filed Apr. 17, 2007, which is incorporated herein by reference.
Number | Date | Country | |
---|---|---|---|
60912247 | Apr 2007 | US |