Abstract:
The present invention is Micro-erosion Recovery System for separating recyclable tire materials (rubber, steel and fiber) and complying with quality standards governing the use of recovered tire materials. It is also a highly efficient apparatus and system for producing large amounts of high quality crumb rubber and steel.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to U.S. Provisional Application No. 61/160,381 filed on Mar. 16, 2009. 
    
    
     FIELD OF INVENTION 
     The present invention relates to the field of tire recycling systems and more particularly to a micro-erosion recovery system (MERS) for tire materials. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates a perspective view of an exemplary configuration of a multi-line micro-erosion recovery (MERS) system for tire materials. 
         FIG. 2  illustrates a perspective view of an exemplary embodiment of two adjacent units of an MERS system. 
         FIG. 3  illustrates a perspective view of an exemplary embodiment of a sidewall cutting assembly of a MERS unit. 
         FIG. 4  illustrates a perspective view of a partial, flattened tire tread. 
         FIG. 5  illustrates a perspective view of an exemplary embodiment of a tread processing station of a MERS unit. 
         FIG. 6   a  illustrates an exemplary embodiment of a crumb processing assembly. 
         FIG. 6   b  illustrates an exemplary embodiment of a water chemical treatment system. 
         FIG. 7  illustrates an exemplary embodiment of a sidewall processing station of a MERS system. 
     
    
    
     GLOSSARY 
     As used herein, the term “sidewall” refers to the portion of a tire between the tread and rim of a tire. A sidewall may be comprised of rubber, steel (or other metal), fiber, Kevlar™ and functionally equivalent materials. 
     As used herein, the term “crumb rubber” refers to recycled rubber that has been reduced to particles. 
     As used herein, the term “steel bead” refers to a portion of the tire against the rim that holds the tire on the rim. 
     As used herein, the term “tire” refers to a rotational component of vehicle which may have a tread, a sidewall, a shoulder, a bead and a belt. 
     As used herein, the term “tread” refers to the region of a tire designed to contact the ground. It is molded of tough rubber for high traction and low wear, which is located between the shoulders. A tread may be comprised of rubber, steel (or other metal) and fiber and functionally equivalent materials. 
     As used herein, the term “shoulder” refers to the portion of the tire which is the transition area between the sidewalls and the tread. A shoulder may be comprised of rubber, steel (or other metal) and fiber and functionally equivalent materials. 
     As used herein, the term “I/O processor” refers to a component which may monitor the functioning of the system intergraded with man-machine interface, the quantity of tires processed, the amount of material recovered, and/or other discrete and analog signals, such as density sensors, location of density sensors, run status of equipment and motor components, and input signals (e.g., robotic sweeping action, robotic grasping action, tire counter, crumb output). I/O processor may generate reports related to MERS processing, may be programmed with revenue processing and inventory control capabilities or other functionality. 
     As used herein, the term “robotic arm” refers to a mechanical component for which movement is controlled by program logic. Movement functionality may be linear or nonlinear. 
     As used herein, the term “robotic sweeping arm” refers to a mechanical component which pushes a tire onto processing channels. 
     As used herein the term “robotic grasping arm” refers to the non-linear movement of a mechanical component positions a tire. 
     As used herein, the term “pulverizes” refers to the act of grinding to a mesh, particles, pieces powder or dust. 
     As used herein, the term “micro-erosion” refers to a process by which water or other fluid pressure is applied to a surface causing the surface erode into smaller particles, pieces, mesh or powder. 
     As used herein, the term “MERS unit” refers to a processing channel having at least one tire processing surface and at least one water jet capable of performing micro-erosion. A tire processing channel may further include one or more robotic arms or components, bins or other assemblies and components used for the process of recycling tire materials using a micro-erosion process. 
     As used herein, the term “uncut rubber tire” means a tire of any size which has not been shredded, cut or disassembled. 
     As used herein, the term “central conveyer” is an mechanical component that moves a tire from one processing channel to another. 
     As used herein, the term “processing channel” means a surface and configuration of water jets used to apply a micro-erosion recovery process to a tire. 
     BACKGROUND 
     There is a need for improved tire recycling operations both to address the need to dispose of used tires in an environmentally sound manner and to satisfy an estimated $68 billion per year demand in the U.S. for rubber. This market increases at a stable rate of approximately 6% per year. 
     In the U.S. alone there is a need to dispose of over $300 million in used tires annually. Approximately 12% of tire refuse currently ends up in landfills. 
     Currently, 52% of used tire refuse in the U.S. is disposed of by creating tire derived fuel (TDF). However, a crisis is emerging in the recycling industry because TDF is a controversial “dirty” type of fuel. TDF fuel fails to meet EPA emission standards. It is expected that this disposal/recycling method will be foreclosed and other methods for recycling and tire disposal will be desperately needed as TDF fuel no longer remains a recycling and disposal option. Only about 17% of refuse tire rubber is presently recovered and re-used to produce actual rubber products. The economics of recycling rubber products are tenuous, because the present art relies on using a cumbersome multi-step process that must be performed at multiple locations. The end usable product is referred to as “crumb rubber.” 
     As consumer demand for products containing ground or crumb rubber is increasing, the desirability of diverting more tire refuse to crumb rubber production is apparent. 
     A recycling crisis coupled with demand for a recycle product create a unique, historic economic opportunity which present rubber recycling and crumb rubber processing technologies cannot address. Industries will pay a premium price both for rubber disposal options and for high quality crumb rubber. It is desirable to have a technology positioned to take advantage of these converging economic trends. 
     Current rubber recovery processes are highly inefficient and marginally profitable, under the best of circumstances. Tire shredding and methods of recovering rubber, steel and fiber from used tires are processes known in the art. Current processes generally recover approximately 78-92 percent of the total rubber material in a tire, but the quality of rubber is substandard for many commercial uses. The end-product rubber contains significant metal contaminant and iron oxide contaminants. These contaminants prevent the rubber from meeting the requirements for end-uses for any high-end products. 
     Water-jet processes for reclaiming rubber from used tires are known in the art; however, these methods require some shredding. These methods are inefficient and lead to contamination, which lowers the value of the recovered rubber. 
     The American Society for Testing and Materials (ASTM), which is an international organization charged with developing standards for rubber and other materials, promulgates standards for rubber which dictate the uses for recovered rubber. ASTM standards establish the level of contaminants and other materials. 
     Crumb rubber, or recycled rubber that has been reduced to particles, is the most valuable type of recycled rubber. The size of the particles is referred to as “mesh size.” 
     Tyler mesh size is the number of openings per (linear) inch of mesh. To calculate the size of the openings in a mesh the thickness of the wires making up the mesh material must be taken into account. In practice, mesh openings are determined referring to a chart like the one below which uses a scale known as the Tyler mesh scale: 
     
       
         
               
               
               
               
               
             
               
               
               
               
               
             
           
               
                   
                   
               
               
                   
                 Sieve size 
                   
                 Tyler 
                 US 
               
               
                   
                 (mm) 
                 BSS 
                 (approx) 
                 (approx) 
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                   
                 4.75 
                 — 
                 4 
                 4 
               
               
                   
                 3.35 
                 5 
                 6 
                 6 
               
               
                   
                 2.81 
                 6 
                 7 
                 7 
               
               
                   
                 2.38 
                 7 
                 8 
                 8 
               
               
                   
                 2.00 
                 8 
                 9 
                 10 
               
               
                   
                 1.68 
                 10 
                 10 
                 12 
               
               
                   
                 1.40 
                 12 
                 12 
                 14 
               
               
                   
                 1.20 
                 14 
                 14 
                 16 
               
               
                   
                 1.00 
                 16 
                 16 
                 18 
               
               
                   
                 0.853 
                 18 
                 20 
                 20 
               
               
                   
                 0.710 
                 22 
                 24 
                 25 
               
               
                   
                 0.599 
                 25 
                 28 
                 30 
               
               
                   
                 0.500 
                 30 
                 32 
                 35 
               
               
                   
                 0.422 
                 36 
                 35 
                 40 
               
               
                   
                 0.354 
                 44 
                 42 
                 45 
               
               
                   
                 0.297 
                 52 
                 48 
                 50 
               
               
                   
                 0.251 
                 60 
                 60 
                 60 
               
               
                   
                 0.211 
                 72 
                 65 
                 70 
               
               
                   
                 0.178 
                 85 
                 80 
                 80 
               
               
                   
                 0.152 
                 100 
                 100 
                 100 
               
               
                   
                 0.125 
                 120 
                 115 
                 120 
               
               
                   
                 0.104 
                 150 
                 150 
                 140 
               
               
                   
                 0.089 
                 170 
                 170 
                 170 
               
               
                   
                 0.075 
                 200 
                 200 
                 200 
               
               
                   
                 0.066 
                 240 
                 250 
                 230 
               
               
                   
                 0.053 
                 300 
                 270 
                 270 
               
               
                   
                 0.044 
                 350 
                 325 
                 325 
               
               
                   
                 0.037 
                 440 
                 400 
                 400 
               
               
                   
                   
               
             
          
         
       
     
     In addition to standard U.S. and Tyler mesh sizes, commercial sieves in the U.S. can also utilize three other standards. 
     A problem known in the art is that tire recycling operations are inherently costly because they involve a number of sequential size reduction steps to convert used tire rubber to “crumb rubber” which is usable for rubber products. 
     Generally, the tire recycling process is a costly, low-yield, high cost process involving one or more of the following steps using multiple machines at multiple locations using conveyors and “air movement” systems:
         Primary shredding process—Cutting/shredding tires into sections using a primary shredding process that reduces the space required for transporting the tires for further processing (i.e., air space within the tire structure). Generally, this will produce remnants of rubber, steel and fiber that vary in size. This process is generally performed by shredding machines, rapsers and other machines for reducing the size of tires known in the art.   Secondary shredding process—Further reduces larger sections of rubber into chips (e.g., 3 inches or less). During this process, rubber, steel and fiber are co-mingled, producing a quantity of mixed fragments of each. This process is generally performed by a “secondary shredder” known in the art.   Tertiary shredding process—This process is a further size reduction process which is generally used to create even smaller chips (depending upon the end use for the product). Currently, tires must be reduced in size in some manner because current machinery known in the art is not adapted to remove rubber directly from tires.   Grinding and hammer milling process—Reducing the chips into rubber particles with varying mesh size (which is a measurement of size reduction based on holes per square inch).   Removing the steel for sale to those respective markets—This process often uses multiple magnets during a sifting process.   Removing the fiber for sale to those respective markets—The machine known in the art that performs this function is generally referred to as an air “classifier” or “air gravity separation chamber.”       

     Generally, the price for which recovered rubber and steel can be sold depends upon the level of contaminants in the product. It is therefore desirable to reduce the levels of contaminants in the product. 
     Rubber which meets the (ASTM) standards for a wider variety of products (e.g., such as off-road tires, automotive, consumer products) can be sold at a higher price. Specific materials standards apply to various types of products. Rubber that does not meet the standard for high-quality uses is sold for less. For example, rubber which meets higher ASTM standards may sell for as much as twelve times the cost of lower quality rubber (e.g., asphalt, fuel grade or aggregate quality rubber). 
     Generally, using current processes, the higher the rubber recovery rate the more metal contaminants the rubber will have. For example, a process which scrapes rubber and avoids contact with the metal tire treads will be reasonably free of metal contaminants, but will have a relatively low recovery rate. A more efficient tire stripping method will recover a greater percentage of rubber, but the rubber will include more iron oxide and metal contaminants. 
     A similar problem exists with regard to steel recovered in the process. Generally, steel recycling (“smelting”) requires recovered steel which has less than 5% rubber (by volume) adhered to the steel. With current tire recycling processes, the higher recovery rates usually result in increased levels of rubber contaminants. 
     It is desirable to have a single integrated machine and/or system to reduce the number of steps and processes necessary to reduce rubber to crumb rubber. 
     It is further desirable to increase the quantity of rubber and steel that can be recovered from each used tire. 
     It is further desirable to increase quality of rubber and steel recovered from used tires consistent with ASTM standards because recovered material has an increased value and can be used for a wider range of purposes. 
     It is further desirable to extend the mechanical life of equipment currently used to recover rubber, steel and fiber from used tires. 
     It is further desirable to integrate the de-vulcanization and re-vulcanization processes with tire recycling and recovery processes. 
     It is further desirable to reduce the operating costs of tire recycling operations. 
     SUMMARY OF THE INVENTION 
     The present invention is a Micro-erosion Recovery System for separating recyclable tire materials (rubber, steel and fiber) and complying with quality standards governing the use of recovered tire materials. It is also a highly efficient apparatus and system for producing large amounts of high quality crumb rubber and steel. 
     DETAILED DESCRIPTION OF INVENTION 
     For the purpose of promoting an understanding of the present invention, references are made in the text to exemplary embodiments of a micro-erosion recovery system (MERS) for tire materials, only some of which are described herein. It should be understood that no limitations on the scope of the invention are intended by describing these exemplary embodiments. One of ordinary skill in the art will readily appreciate that alternate but functionally equivalent micro-erosion recovery systems for tire materials may be used. The inclusion of additional elements may be deemed readily apparent and obvious to one of ordinary skill in the art. Specific elements disclosed herein are not to be interpreted as limiting, but rather as a basis for the claims and as a representative basis for teaching one of ordinary skill in the art to employ the present invention. 
     It should be understood that the drawings are not necessarily to scale; instead, emphasis has been placed upon illustrating the principles of the invention. In addition, in the embodiments depicted herein, like reference numerals in the various drawings refer to identical or near identical structural elements. 
     Moreover, the terms “substantially” or “approximately” as used herein may be applied to modify any quantitative representation that could permissibly vary without resulting in a change in the basic function to which it is related. 
       FIG. 1  is an exemplary embodiment of multi-line MERS system  100  comprised of MERS units  10 ,  12 ,  14 ,  16 ,  18  and  19 . In the embodiment shown, six MERS units are shown, five of which operate simultaneously and one line is redundant (back up) line to prevent operational downtime in the event of mechanical failure and maintenance. Other systems may have more or fewer or differently configured MERS lines. In the embodiment shown, MERS units  10 ,  12 ,  14 ,  16 ,  18  and  19  are positioned in a linear configuration. In alternative embodiments, MERS units  10 ,  12 ,  14 ,  16 ,  18  and  19  may be configured in a lateral stacked configuration, circular configuration semi-circular configuration, I-shaped configuration, angular configuration or any other configuration necessary to accommodate the space constraints of a building. 
     In the embodiment shown, tire  2  is loaded into conveyer entry point  22 , and loading may be accomplished using a variety of methods and apparatus configurations. For example, tires may be loaded onto conveyor entry point  22  with a stationary or movable rod or belt (not shown) extending through the tires&#39; central holes. In another example, tires can be stacked for processing on stationary or movable table, rack, belt, etc. 
     Tires may be car, truck, tractor, semitractor, transport, airplane tires, off-road tires, machinery tires, monster tires or any other tire known in the art which is constructed of rubber, steel, fiber, Kevlar™ and functionally equivalent materials. MERS units  10 ,  12 ,  14 ,  16 ,  18  and  19  can recover any of the foregoing materials. 
     Tire  2  (from which the rim has been removed) passes through wash station housing  30  which encases a series of water spray nozzles (not shown) known in the art which are used to clean and remove debris from tires  2 . Tires  2  are moved along conveyer belt which is any type of conveyer apparatus or functionally equivalent device known in the art. 
     Tire  2  further included sidewalls and treads, which may consist of rubber, fiber, steel, Kevlar™. As illustrated in  FIG. 2 , MERS system is configured with a plurality of tire position sensors  43   a ,  43   b  that sense the position of each tire  2  along conveyer  9  and send an electronic signal (hardwired or wireless via a local or distributed network) to I/O processor  40 . 
     I/O processor  40  may monitor the functioning of the system, the quantity of tires processed, the amount of material recovered and all discrete and analog signals. I/O processor  40  may generate reports related to MERS processing, may be programmed with revenue processing and inventory control capabilities or other functionality. 
     I/O processor  40  is configured with software and program logic which interprets the multiple signals sent by tire position motion sensors to communicate the position of the tires along the conveyer with a plurality of first robotic sweeping arms  50  which sequentially divert tires  2  into processing channels  5   a ,  5   b.    
     In the embodiment shown, robotic sweeping arms  50   a ,  50   b  (shown in  FIG. 2 ) and robotic grasping arms  53   a ,  53   b  use servo motors known in the art or any functionally equivalent motor adapted to control robotic components using electronic signal. In the embodiment shown, robotic grasping arms  53   a  and  53   b  include robotically controlled brackets or pads which exert counter pressure to lift tires  2 . 
       FIG. 3  illustrates an exemplary embodiment of a tire  2  being grasped by robotic grasping arm  53   a  in a substantially upright position after tire  2  has been directed into channel  5   a . Robotic grasping arm  53   a  has the capability of movement up to six non-linear axis to enable sidewall cutting implement  82  to cut the sidewalls off tire  2 . Sidewalls  51  fall onto lower conveyor  51  and are moved toward sidewall processing station shown in  FIG. 7 . 
     In various embodiments, MERS system  100  may utilize high-precision robotic positioning systems for use in a wide variety of applications. For example, MERS robotic arms may be based on various robotic systems known in the art offering high load capacity and range of movement while maintaining a high degree of precision and repeatability. 
       FIG. 3  further illustrates sidewall cutting assembly  80 , which includes sidewall cutting implement  82 . In various embodiments, sidewall cutting implement  82  may be a laser jet, water jet, blade or knife positioned to remove sidewall. The movement of sidewall cutting implement  82  may be controlled by robotic or other simple mechanical means. 
     Sidewall cutting assembly further includes tread cutting implement  87  which slits the tread (which is comprised of rubber, and fiber) so that the tread portion  88  can be stretched into a single linear configuration which is fed into roller assembly  89  where tread portion  88  it is stretched flat between two conveyors and moved toward tread processing station  60  (shown in  FIG. 5 ). Sidewalls  55  and  56  drop onto sidewall conveyer  59  and are conveyed or otherwise moved toward sidewall processing station  70  (shown in  FIG. 6 ). 
       FIG. 4  illustrates a top view of tread portion  88 , having rubber portions  86  and steel portions  84 , of which tread portion  88  is comprised. 
       FIG. 5  illustrates an exemplary embodiment of an MERS tread processing station  60 . Tread processing station includes a series of underside water jets  64  which are directed to the underside of the tread and a series of topside water jets  66  which are directed to the topside of the tread. 
     When activated, underside water jet  64  and topside water jet  66  direct a stream of water at a high speed and pressure over the topside tread surface  16  and underside tread surface  17 . 
     Because of the speed/pressure and flow rate of the water, a multitude of tiny cracks or cavities are progressively formed in the surface of the rubber, causing the rubber surface to separate into a fine mesh powder (“pulverized”). This process is known in the art as micro-erosion. 
     The size of the particles is referred to as “mesh size.” The mesh size of the particles in the exemplary embodiment shown may range from 400 mesh to in excess of 1 mesh on the Tyler mesh scale. (Other mesh scales may be applied). 
     In the embodiment shown, the mesh size of the particles processed by jets  64 ,  66  is 1-400 mesh, as defined by the Tyler mesh scale. 
     Water jets  64 ,  66  have a psi of 2,000 to 200,000. The angle of the nozzle relative to the tread enables changing of mesh size based on the angle of the nozzle relative to the tire and the distance the nozzle is from the tire. 
     In the embodiment shown, the mesh size of the particles after exposure to the water stream from jets  64 ,  66  is determined by three variables: the angle of nozzle (nozzle position), the distance of the water jet nozzle (“distance”) relative to tread and the psi of water jets  64 ,  66 . Nozzle position, distance and psi can be independently varied, or may be adjusted in combination to yield an optimum crumb rubber mesh size. 
     As the distance of the nozzle increases relative to the tread, if nozzle position and psi remain constant, the mesh size of the particle will generally increase. 
     As the pressure increases, assuming position and distance remain constant, mesh size of the crumb rubber particles will generally decrease. 
     Nozzle position, distance and psi can be independently varied or varied in combination to affect the speed of process (“through put”). 
     As crumb rubber is produced by MERS tread processing station  60 , it is moved by conveyor to receptacle or repository for packaging. Crumb rubber and water produced during the water jet process may be collected using any apparatus or method known in the art such as screening, multiple screening, filtration, sodium zeolite softening, Ph adjustment, total hardness adjustment and chloride control. Separation may also be accomplished by electrical or mechanical means such as air blowing, sonic and ultrasonic field separation and centrifuges. 
       FIG. 6   a  illustrates an exemplary crumb processing assembly  600  for crumb rubber collection, water filtration and treatment. In the embodiment shown, water and crumb rubber particles fall downward from tread processing station  60  (shown in  FIG. 5 ) and passes through a series of mesh screens  91 ,  92 ,  93 ,  94  where the crumb rubber is collected and removed from the screens. Water from the jet cutting process described infra is collected in holding tank (sump)  95  to retrieve additional crumb rubber particles pumped using pump  96  and for reuse in the process. The additional crumb rubber particles retrieved from filtering are dried using drying apparatus  102  which is an air blowing or heat apparatus known in the art. In various embodiments, drying apparatus may also use other processes known in the art such as air blowing, sonic and ultrasonic field separation and centrifuges. Filtered and screened crumb rubber particles may then be transported and/or packaged for use, and will generally meet high market value ASTM standards. 
       FIG. 6   b  illustrates exemplary water chemical treatment station  700 . In the embodiment shown, water is pumped through pump  98 , passes through sodium zeolite softening processor  991 , Ph adjustment processor  992 , total hardness adjustment and chloride adjustment processing  993 . 
       FIG. 7  illustrates an exemplary embodiment of a MERS sidewall processing station  70 . 
     Sidewall processing station  70  includes a series of water jets  72  that are directed to sidewall  56  and pulverized the rubber component, stripping the steel bead (not shown) clean using the process described in  FIGS. 5 ,  6   a  and  6   b.