Abstract:
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 in 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 by removing at least one component of the remaining material stream from the sorter.

Description:
[0001]    This application takes priority from U.S. provisional application 60/912,247 filed Apr. 17, 2007, which is incorporated herein by reference. 
     
    
     BACKGROUND 
       [0002]    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. 
       SUMMARY 
       [0003]    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. 
         [0004]    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. 
         [0005]    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. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0006]    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. 
           [0007]      FIG. 1  is a schematic view of a sorting device with material detectors defining two detection zones for sorting two types of materials from a material stream; 
           [0008]      FIG. 2  is a cross sectional top view of the sorting device of  FIG. 1  showing an array of sensors across the width of the material handling system; and 
           [0009]      FIG. 3  is a schematic view of a sorting device with material detectors defining two detection zones for sorting more than two types of materials from a material stream. 
       
    
    
     DETAILED DESCRIPTION 
       [0010]    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. 
         [0011]      FIG. 1  shows one embodiment in which a new or existing sorter machine  10  has been configured to sort multiple materials in multiple zones. The sorter machine  10  is a ProSort manufactured by Eriez Magnetics, however, any sorter having definable detection zones as described herein may be used. The sorter machine  10  has a material introduction system  12  that is a vibrating chute angled to deposit a material stream onto a material handling system  14 . The material handling system  14  comprises a conveyor belt that transports the material stream from about a first end  16  where the material stream is deposited to about a second end  18  where the material stream is sorted by a sorting system  20 . It will be understood that any other means than shown may be used for the material introduction system  12  and the material handling system  14 . 
         [0012]      FIG. 2  shows a cross sectional top view of the material detection system and the sorting system  20  of the sorter  10 . As best understood by comparing  FIGS. 1 and 2 , the material detector system on this sorter machine  10  comprises an array of seven control modules  38  across the width of the material handling system  14 . Each control module  38  comprises six individual sensors  40 , with the exception of the seventh control module  38  that comprises four individual sensors  40 . It will be understood that the number of sensors in each control module  38  is arbitrary and can be defined on a case-by-case basis. Any sorter machine  10  that can configure its material detector system into at least two adjacent detection zones would be equally able to perform various embodiments of the invention. 
         [0013]    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. 
         [0014]    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 . 
         [0015]    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. 
         [0016]    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 . 
         [0017]    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. 
         [0018]    In contrast, the embodiment depicted in  FIGS. 1 and 2  would allow for sorting multiple materials simultaneously and potentially continuously on the same machine. For the purposes of illustration, if the material stream comprises a mix of metals and non-metals with the metals including stainless steel and other metals, the sensors  40  in the first detection zone  22  can be configured to detect all metals in the first detection zone  22  from the material stream. The control system  26  can be set to direct the sorter system  20  to deflect all metals to a material return system  30 . Any non-metals would drop past the sorter system  20  to a first collection system  32  (in this case a collection bin) and may be discarded or further processed as required. In the embodiment shown in  FIG. 1 , the material return system  30  comprises a series of conveyors that returns the prior deflected all metals to the material introduction system  12 . The prior deflected all metals 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 prior deflected all metals material stream to the second detection zone  24 . The sensors  40  in the second detection zone  24  can be configured to detect all stainless steel from the prior deflected all metals material stream. The control system  26  can be set to direct the sorter system  20  to deflect all the stainless steel from the second detection zone  24  to an appropriate second collection system  34  (in this case a conveyor system) while any other metal product that does not trigger the detector system will drop past the sorter system  20  to a third collection system  36  (in this case another conveyor system). 
         [0019]    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. 
         [0020]    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  FIG. 1 , or it can be a collection bin that is manually returned to the material introduction system  12  at the appropriate location. Other types of material return systems or collection area are also possible. 
         [0021]    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 . 
         [0022]    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. 
         [0023]    It is also possible to define more detection zones than the two depicted in  FIG. 1 . This would allow for further sorting of components of the material stream in the detection system. In such embodiments, the material return system would have to be configured to return each round of sorted material to the appropriate consecutive detection zone. 
         [0024]    There are many types of sorters that separate recyclable materials from material streams using a variety of technologies. While the detection system described in  FIG. 1  was shown by example to detect metals and stainless steel from a material stream, the material detector system can generally be any component or system that can distinguish one or more materials from other materials and produce a digital or analog signal to indicate the presence of the distinguished material. The detection system can comprise an induction system, an X-Ray Fluorescence system, an optical detection system, a near-infrared detection system, or any other kind of detection technology. The detection system could also comprise a combination of technologies with, for example, a different sensor technology for each detection zone. 
         [0025]    The sorter is not limited to the sorter system depicted in  FIG. 1 . Any other type of sorting system is equally applicable. The sorter system could comprise a series of nozzles that shoot jets of compressed air to deflect material in a material stream based on a signal from the detection system. The sorting system could be an electromagnetic system that is actuated by a signal from the detection system to deflect target metals. The sorter could be any other kind of system that can deflect or otherwise sort materials for collection or return. 
         [0026]    The material handling system is not limited to a conveyor belt as depicted in  FIG. 1 . Any other type of material handling system is equally applicable. For example, the material handling system could be a chute that moves the material stream by gravity past the detection system and to the sorting system. Any other kind of material handling system that can move the material stream through the detection system to an appropriate sorting system would also work. 
         [0027]    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. 
         [0028]    Some sorters can sort more than one type of material from a material stream.  FIG. 3  shows an embodiment of how such sorters can be used. For the purposes of illustration, if the material stream comprises a mix of metals, plastics, and other debris with the metals including stainless steel and other metals, the sensors in the first detection zone  22   a  can be configured to detect all metals and plastics in the first detection zone  22   a  from the material stream. The control system  26   a  can be set to direct the sorter system  20   a  to deflect all metals to a material return system  30   a  and to deflect the plastics to a plastics collection system  38   a  for separate processing or collection as needed. Any other debris would drop past the sorter system  20   a  to a first collection system  32   a  (in this case a collection bin) and may be discarded or further processed as required. In the embodiment shown in  FIG. 3 , the material return system  30   a  comprises a series of conveyors that returns the prior deflected all metals to the material introduction system  12   a . The prior deflected all metals material stream is deposited at about the first end  16   a  of the sorter machine  10   a  on the material handling system  14   a  in such a way as to substantially limit the prior deflected all metals material stream to the second detection zone  24   a . The sensors (not shown) in the second detection zone  24   a  can be configured to detect all stainless steel from the prior deflected all metals material stream. The control system  26   a  can be set to direct the sorter system  20   a  to deflect all the stainless steel from the second detection zone  24   a  to an appropriate second collection system  34   a  (in this case a conveyor system) while any other metal product that does not trigger the detector system will drop past the sorter system  20   a  to a third collection system  36   a  (in this case another conveyor system). If another component of the prior deflected all metals material stream can be detected and there is some commercial value to doing so, the sorter system  20   a  can be programmed to sort this additional component into a fourth collection system  40   a . The choices of materials in this embodiment are for example purposes only. The limitations on what materials can be sorted will depend on the particular material stream observed by the facility, the ability of the sensors to detect the various components of the material stream, and the ability of the sorter system to appropriately deflect the detected material into appropriate collection and/or return systems. 
         [0029]    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.