Abstract:
An automated system for producing a slug having a repeatable shape from a plastic bottle, the automated system comprising: a housing having an elongated shape, an axis in a direction of elongation, and an opening configured to receive the bottle in a generally coaxially orientation with the housing; a compacting subsystem adapted to compact the bottle substantially in a first direction within the housing; and a slug processing subsystem adapted to form a slug having an essentially predefined form from the compacted bottle, the slug processing subsystem adapted to form the slug by application of force in at least a second direction, substantially normal to the first direction; wherein the slug processing subsystem is adapted to form a slug from a single compacted bottle; wherein the slug processing subsystem is configured to form a slug having a flattened geometric shape; wherein the flattened geometric shape is a polygon having a characteristic dimension less than 90 millimeters.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application is a US National Phase of PCT Application No. PCT/IL2006/001018, filed on Aug. 31, 2006, which claims the benefit under 35 U.S.C. 119(e) of US Provisional Application 60/739,436 filed Nov. 25, 2005, the disclosure of which is incorporated herein by reference. 
    
    
     FIELD AND BACKGROUND OF THE INVENTION 
     The present invention relates to recycling of plastics and, in particular, it concerns formation of compact repeatable shaped slugs, for recycling or for other use, from PET and other plastic bottles. In the description and claims hereinbelow, the terms “PET bottle” and “plastic bottle” refer to any thermo deformable bottle or container generally designed to be discarded after use. The term “slug”, as used in the description and the claims which follow, generally refers to a compacted/crushed/squashed/chopped plastic bottle. The term “repeatable”, as used in the description and the claims which follow, is intended to mean a result or a product (such as the shape of a slug) that is invariant in its dimensions (for example) within a given tolerance, the tolerance usually equal to a few percentages of the dimensions. 
     In the “2003 Report on Post Consumer PET Container Recycling Activity”, National Association of PET Container Resources, September 2004, whose disclosure is incorporated herein by reference, it is cited that despite the growing annual rate of usage of plastic drinking bottles (from nearly a million tons of bottles consumed in 1995 to approximately 2 million in 2003), the amount of recycled plastic has not significantly changed in past years and has even declined—from 400,000 tons in 1995 to 350,000 tons in 2002. This data infers an unfortunate negative trend in recycling activities, especially with regard to plastic bottles. 
     In developed countries protecting the environment by recycling has been defined as a national task. Countries have traditionally committed themselves to specific recycling rate objectives, however the data described hereinabove serves to underscore the need for increased recycling. One way to accomplish this is by the wide scale use of low cost recycling equipment to compact bottles, especially equipment directed for widely distributed home or non-industrial use. 
     There are number of publications related to plastic bottle compaction equipment which may be directed for home use. The following patent publications, whose disclosure is incorporated herein by reference, cite devices, ostensibly for home or non-industrial use, for squashing and/or crushing plastic bottles:
         Metayer, French Patent Application no. 2692190;   Ducreuez, French Patent Application no. 2668732;   Vallee, French Patent Application no. 2712230;   Seidel, German Patent publication no. DE10121599A1;   Montipo, European Patent Application no. EP 149675A2;   Miller, U.S. Pat. No. 6,481,346; and   Lajos Simon, US Patent Application no. 2005/0115420       

     Devices illustrated and otherwise described in the French and German applications listed hereinabove apply mechanical force (which, in some cases, is motorized) and apply heat to compress, squash, and otherwise compact a plastic bottle. 
     Montipo, in European Patent Application no. EP149675A2, discloses a bottle squashing device apparently for table top or counter top use, which employs a pressurized steam supply source to aid in reducing the volume of small disposable containers generally of between 250 and 2000 ml capacity. 
     The US publications noted hereinabove, by Miller and by Lajos Simon, respectively, disclose devices for application of manual turning power to crush a plastic bottle. 
     Some of the prior art listed hereinabove describe or otherwise show slugs formed after squashing/crushing/compacting in a substantially axial direction. Although somewhat flattened to an approximate thickness of 2 cm or more, the resultant slugs maintain approximately the initial bottle diameter dimension, and thus the slugs are still relatively large. In general, all of the prior art noted above suffers from the following disadvantages:
         a slug is produced that is relatively large, especially in diameter, and of variable shape, making subsequent handling, storage, and recycling of slugs more difficult;   the slug produced is not readily removed from the system, thereby necessitating a possibly cumbersome manual removal process;   the systems do not generally have any controlled way of storing liquids drained from compacted bottles and/or the compacting process; and   there is no integrated storage capability for produced slugs.       

     There is therefore a need for a low cost system that can automatically or semi-automatically produce compact and repeatably shaped slugs from compacted plastic bottles, while handling the slugs and liquids from the compacting and slug forming processes in an automated or semi automated fashion. 
     SUMMARY OF THE INVENTION 
     The present invention is a system to form repeatable shaped slugs from a plastic bottle. 
     According to the teachings of the present invention there is provided a system for producing a slug having a repeatable shape from a plastic bottle, including: a housing having an elongated shape, an axis in the direction of elongation, and an opening configured to receive the bottle in a generally coaxially orientation with the housing; a compacting subsystem adapted to compact the bottle substantially in a first direction within the housing; and a slug processing subsystem adapted to form a slug having a predefined form from the compacted bottle, the slug processing subsystem adapted to form the slug by application of force in at least a second direction, substantially normal to the first direction. Most preferably, the slug processing subsystem is configured to form a slug having a flattened geometric shape. Preferably, geometric shape is a polygon, having a characteristic dimension less than 90 mm. Most typically, the geometric shape is a circle having a diameter less than 90 mm. Most, preferably, the slug processing subsystem is further adapted eject the slug following slug formation. Preferably, a flattened dimension of the flattened geometric shapes is less than 25 mm. Typically, the slug processing subsystem further includes a slug magazine adapted to store a plurality of ejected slugs. Typically, the compacting subsystem is further adapted to collect and store drained liquid from the compacted bottle. Most preferably, the first direction is the axial direction. Preferably, the compacting system is further adapted to compact, chop, grind, and heat the bottle. 
     There is further provided a method of controllably producing a slug having a repeatable shape from a plastic bottle which is compacted, including the steps of: taking a housing having an elongated shape, an axis in the direction of elongation, and an opening configured to receive the bottle in a generally coaxially orientation with the housing; configuring a compacting subsystem to compact the bottle substantially in a first direction within the housing; and utilizing a slug processing subsystem to form a slug having a predefined form from the compacted bottle, the slug processing subsystem forming the slug in a second direction by applying force in at least a second direction, substantially normal to the first direction. Most preferably, forming a slug further includes forming a slug having a flattened geometric shape. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention is herein described, by way of example only, with reference to the accompanying drawings, wherein: 
         FIG. 1  is a schematic illustration of a system for producing a slug having a repeatable shape from a plastic bottle, in accordance with an embodiment of the current invention; 
         FIGS. 2A and 2B  are schematic isometric illustrations of the system of  FIG. 1 , showing some detail of the slug processing subsystem, in accordance with an embodiment of the current invention; 
         FIGS. 3A-B  are schematic isometric illustrations of parts of the slug processing subsystem shown in  FIGS. 2A and 2B ; 
         FIGS. 4A-G  are illustrations of exemplary repeatable shaped slug geometries formed by the slug processing subsystem in accordance with embodiments of the current invention; and 
         FIG. 5  is a schematic illustration of a system for producing a slug having a repeatable shape from a plastic bottle, in accordance with another embodiment of the current invention. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The present invention is a system to form repeatable shaped slugs from a plastic bottle 
     The principles and operation of the system to form repeatable shaped slugs from a plastic bottle, according to the present invention may be better understood with reference to the drawings and the accompanying description. 
     Referring now to the drawings,  FIG. 1  is schematic illustration of a system  10  for producing a slug (not shown in the figure) having a repeatable shape from a plastic bottle  12 , in accordance with an embodiment of the current invention. System  10  has an elongated shaped with an axis in the direction of elongation and is shown in the figure with plastic bottle  12  in an inverted position (i.e. with the opening of the bottle facing downward) inside of a housing  13 , before the bottle is compacted. System  10  includes a compacting subsystem  14  and a slug processing subsystem  15 . Compacting system  14  includes, inter alia, a compaction surface  16  and a liquid drain reservoir  17 . Liquid reservoir  17  serves to store any liquid drained from bottle  12  before or during compaction and/or slug processing. Liquid reservoir may be in the form of a reusable container which may be removed, emptied, and replaced in compacting system  15 . Alternatively or additionally, liquid reservoir, when filled, may be discarded and replaced by another liquid reservoir. 
     Compaction of bottle  12  is typically performed by compression or by compression and heating of the bottle, as is know in the art. In the current embodiment of system  10 , the bottle is crushed by compaction surface  16 , which is driven from the bottom of system  10  upwards so that the slug is then presented to slug processing subsystem  15 , with the compaction surface constraining the slug from below. 
     Slug processing subsystem  15  is then activated to form a repeatable shaped slug (examples of which are shown in subsequent figures). Slug processing subsystem  15  includes, inter alia, a slug ejection opening  18 , through which repeatable shaped slugs are ejected following processing, and a magazine  19  where processed and ejected slugs are stored. Magazine  19  typically has a capacity to store  10  or more processed slugs, but variable capacities may be used. The magazine may be removed for emptying and then reattached to slug processing subsystem  15 . Additionally or alternatively, magazine  19  may be specially-designed so that when it is filled with slugs, the magazine is removed from the subsystem for further processing, along with the slugs, and a second, replacement empty magazine is attached to the slug processing subsystem. Additionally or alternatively, liquid reservoir  17  may be connected and drain to magazine  19 , so that liquids and processed slugs are stored in the magazine until the magazine is emptied. Sensors (not shown in the figures) may be employed to give indications of respective weights and, as a result, respective capacities of the magazine and/or of the liquid reservoir to avoid overfilling. Additional details of slug processing system  15  are discussed hereinbelow in subsequent figures. 
     The size of bottle  12  processed in system  10  may vary from approximately 300 ml to approximately 3 liters, although larger and smaller bottles may be processed with correspondingly larger and smaller systems, mutatis mutandis. 
     Reference is now made to  FIGS. 2A and 2B , which are schematic isometric illustrations of system  10  of  FIG. 1 , viewed from the side and above and from the side and below, respectively; the figures showing some detail of the slug processing subsystem  15 , in accordance with an embodiment of the current invention. Reference is also made to  FIGS. 3A and 3B , which are exploded illustrations of some components of slug processing subsystem  15 , viewed from above and below, respectively. (Some components of subsystem  15  have been removed in the exploded illustrations of  FIGS. 3A and 3B  for the purpose of clarity. In addition, central axes indications have been added to  FIGS. 3A and 3B  to illustrate the relative positioning of component parts. The central axes are substantially collinear with the axis of system  10 .) Apart from differences described below, system  10  shown in  FIGS. 2A and 2B  is generally similar to operation of the system as shown in  FIG. 1 , and subsystem  15  is generally similar to operation of the subsystem shown in  FIGS. 2A and 2B , so that elements indicated by the same reference numerals are generally identical in configuration and operation. 
     A tilting arrangement of compacting subsystem  14 , as shown in  FIGS. 2A and 2B , allows loading bottle  12  from an axial opening  20  into housing  13 . Following loading of bottle  12 , housing  13  is righted to allow bottle compaction to proceed. An alternate configuration (not shown in the figures) of compacting subsystem  14  allows loading the bottle from a lateral opening in housing  13 . Another alternate configuration (not shown in the figures) of compacting subsystem  14  and subsystem  15  allows loading the bottle axially from the top end of the housing, by hinging or otherwise displacing and replacing slug processing subsystem  15  to allow the bottle to be loaded. Heaters  13   a  may be optionally configured on the housing periphery, near the slug processing subsystem  15  to heat the bottle during compaction, as well as to provide heat to the slug as it is presented to subsystem  15 . A motor  21 , which is part of compacting subsystem  15 , serves to provide force and displacement to drive compaction surface  16  (shown in  FIG. 1 ) and thereby crush the bottle. 
     Slug processing subsystem  15  includes, inter alia: a support plate  22 ; a slotted drive disc  24 , a heater retention disc  25 , four formation inserts  28 , a slug retention disc  30 , and a processed slug ejection arm  31 . Support plate  22  has a generally square shape with a circular central opening  41  (refer to  FIG. 3A ). Four guide fillets  42  are formed in the underside of support plate  22 , extending radially from central opening  41  and perpendicularly to each of the four edges of the support plate. Four guide slots  43  are formed in support plate  22 , centered on guide fillets  42  and extending radially from central opening  41  and perpendicularly to each of the four edges of the support plate, but terminating before central opening and before the edges of support plate  22 . Slotted drive disc  24  has a central opening  44  approximately the same dimension as central opening  41 . The slotted drive is positioned concentrically and upon support plate  22 . Heater retention disc  25 , which may be heated either electrically or by other means, is positioned concentrically within central opening  44 , so that the lower face of the heater retention disc is flush with the upper edge of guide slots  43 . Heater retention disc  25  is mechanically fixed (such as by brazing or welding, for example) to slotted drive disc  24  and it serves to heat the slug during slug processing. 
     Formation inserts  28  (viewed in  FIG. 3B ) are formed to fit within the four guide fillets and flush with the lower surface of support plate  22 , with mechanical tolerances allowing a snug fit but allowing relative motion. Each formation insert has a hole  46  formed, as shown in the figure. Hole  46  is formed with tapping, blind tapping (i.e. the hole does not extend to the bottom surface of the formation inserts). The formation inserts are formed so that when they are translated radially inward and join as shown in the figure, they form a closed geometric space  52  (viewed in  FIGS. 2B and 3B ) which serves as a form for the repeatable shaped slug. Although the current figures show geometric space as a hexagonal shape, other shapes of closed geometric space  52  may be formed by appropriately changing the shape and relative positions of formation inserts  28  to yield various repeatable shaped slugs. 
     Four bolts (not shown in the figure) are fixedly connected to the formation inserts in the holes. The bolts extend upwards through the respective guide slots, serving to maintain respective formation inserts flush against the upper surface of respective guide fillets  42 , but with sufficient mechanical clearance to allow the formation inserts to slide within the guide fillets. The bolts further extend upwards and pass through and terminate above four respective spiral guide slots  45  which are formed in slotted drive disc  22 . Spiral guide slots (more easily viewed in  FIGS. 3A and 2A ) are partially eccentrically formed in the slotted disk drive as shown so that when slotted disc drive  22  is rotated in one direction about the central axis, the bolts are urged radially outwards, and thereby displace the formation inserts radially outwards. When the slotted disk drive is rotated in the opposite direction, the bolts are urged radially inwards, thereby displacing the formation inserts radially inwards. Slug retention disc  30  (viewed in  FIGS. 2B and 3A ) has a circular form with a retention disc opening  48  formed to be equal to or larger than the diameter of the slug (not shown) presented by the compaction surface described hereinabove. Slug retention disc is attached to the underside of support plate  22  and is maintained flush against the formation inserts, with sufficient clearance to allow formation inserts  28  to move freely. The diameter of disc opening  48  is designed to be slightly smaller than the diameter of the compaction surface, so that when the slug is presented by the compaction surface, the compaction surface abuts slug retention disc  30 , thereby constraining the slug within the slug processing subsystem. 
     Processed slug ejection arm  31  (viewed in  FIG. 2B ) has an elongated form, terminating in shape approximately matching part of the periphery of slug retention disc  30 , as shown. Processed slug ejection arm  31  has a thickness ranging from approximately 15 to 25 mm. The processed slug ejection arm is supported and maintained flush with slug retention disc  30  by drive axis  55  as shown. Drive axis  55  passes through support plate  22  and is rotated either manually or electrically thereby rotating processed slug ejection arm  31 , which when rotated, passes beneath retention disc opening  48  and beneath closed geometric space  52 . 
     Overall operation of slug processing subsystem  15  is as described hereinbelow. At the start of slug processing, formation inserts  28  are in their respective furthermost positions from the central axes shown in  FIGS. 3A and 3B . As the bottle is compacted by the compaction subsystem, compaction surface  16  drives the slug upward into the slug processing subsystem, namely between the retracted formation inserts and up against heater retention disc  25 . Heater retention disc  25  is energized and is thermostatically controlled to maintain an appropriate temperature of the incoming slug during slug processing. Disc  24  is rotated so that formation inserts  28  are driven radially inwards to form closed geometric space  52  and thereby forming the slug into the repeatable slug shape. Disc  24  is then rotated so that formation inserts  28  are translated to their respective furthermost positions from the central axes, thereby releasing the repeatable shape slug, which presently rests on the compaction surface. The compaction surface is then lowered, typically from 30 to 40 mm, and processed slug ejection arm  31  is operated to sweep the repeatable shape slug off of the compaction surface and out through slug ejection opening  18  to the magazine (refer to  FIG. 1 ). Subsystem  15  is then ready to receive the next slug. An additional or alternative configuration of subsystem  15  (not shown in the figures) allows the subsystem, upon completion of slug processing, to be displaced normal to the axis of the compaction subsystem and above the magazine (refer to  FIG. 1 .), allowing the processed slug to drop into the magazine. 
     It should be noted that most parts of subsystem  15  are made of materials (such as, but not limited to: aluminum and steel) which must withstand mechanical strain as well as elevated temperatures. In addition, parts which must move with tight tolerances are made of materials and may have coatings which offer low friction, such as but not limited to aluminum with appropriate anodization and metal with Teflon coatings. Although the figures and description hereinabove for subsystem  15  are for support plate  22  having an overall substantially square configuration and four formation inserts, it may be understood that more or less than four formation inserts may be used with subsystem  15  and that support plate may have another configuration, mutatis mutandis, to allow formation of repeatable shape processed slugs. 
     Reference is now made to  FIGS. 4A-G , which are illustrations of exemplary repeatable shaped slug geometries formed by the slug processing subsystem, in accordance with embodiments of the current invention. A characteristic dimension “d” indicated in the  FIG. 4B  is a diameter of a circle that subscribes the geometries as shown in  FIGS. 4A , C-G. Characteristic dimension “d” ranges from 40% to 80% of the plastic bottle diameter and “d” is typically ranges from approximately 50 mm to 90 mm for a repeatable slug shaped from a typical 1.5 liter plastic bottle. As noted hereinabove, in addition to exemplary geometries shown in the figure (namely: square; rectangle; triangle; octagon; circle; and hexagon) other repeatable shaped slug geometries may be formed by the slug processing subsystem. 
     Reference is now made to  FIG. 5 , which is a schematic illustration of a system  110  for producing a slug (not shown in the figure) having a repeatable shape from plastic bottle  112 , in accordance with another embodiment of the current invention. System  110  has an elongated shaped with an axis in the direction of elongation. Plastic bottle  112 , similar to plastic bottle  12  shown in  FIGS. 1 and 2A , is loaded coaxially into the system and is constrained within a housing  113 . The plastic bottle is compacted in an axial direction by a compacting subsystem (not shown in the figure) towards a slug processing subsystem  115 . Slug processing subsystem  115  includes: a bottle chopper unit  120 ; a fine grinder unit  124 ; an injector unit  132 ; and a repeatable shape slug form. Bottle chopper unit  120  receives the plastic bottle. The bottle chopper unit may apply heat to the plastic bottle during chopping. The chopped bottle is then driven into fine grinder unit  124 , which further grinds and further heats the chopped bottle. Fine grinder unit  124  drives the chopped and ground bottle in a direction normal to the initial plastic bottle axis towards injector unit  132 , which is heated. A drive screw (not shown in the figure) is attached to motor  126 , which serves to turn the drive screw and to drive the chopped and ground bottle towards and into the injector unit. Repeatable shape slug form  134  is fitted onto injector unit  132  and receives the heated, finely ground, and now partially liquified plastic bottle from the injector unit to form a repeatable shape slug having, among others, exemplary geometries as shown in  FIGS. 4A-G . 
     Slug processing subsystem  115  may be designed to have various repeatable shape slug forms to form various slug geometries. Furthermore, slugs may be stored manually or automatically in a slug storage magazine (not shown in the figure). 
     It will be appreciated that the above descriptions are intended only to serve as examples, and that many other embodiments are possible within the scope of the present invention as defined in the appended claims.