SYSTEMS AND METHODS FOR RECYCLING THIN-SECTION MATERIALS
20170362028 · 2017-12-21
Assignee
Inventors
Cpc classification
B65F2210/181
PERFORMING OPERATIONS; TRANSPORTING
International classification
Abstract
Specially-designed rack and plastic bag, and methods of use. The bag is mounted on the rack with a lower portion of the bag disposed inwardly and downwardly of the top of the rack, and an upper portion of the bag disposed outwardly and downwardly of the top of the rack. Workers place thin-section waste material into the bag. When the bag is full, the bag is replaced with an empty bag. The bag has holes, which enable air to escape through bag side walls while the bag is being compressed in a baler. Because air escapes through the side walls, more of the air can be removed for a given baler compaction force thereby the resulting bale weighs about 10% to about 25%, or greater, more than a bale made with the same materials and the same baler conditions, without use of the rack and bags of the invention.
Claims
1. In combination, a rack adapted and configured to hold a bag, and a bag adapted and configured to be held on said rack, while waste material is being placed in said bag. said rack comprising a base section defining a bottom of said rack, said bottom of said rack being adapted to interface with an underlying support, said base section further comprising a base section length, front-to-back, and a base-section width, side-to-side, perpendicular to the base section length, an upper section adapted to be disposed above said base section, said upper section defining a top of said rack, said upper section having an upper section length, front-to-back, an upper section width, side-to-side, perpendicular to the upper section length, and an upper section circumference, the upper section circumference extending across any open spaces between next adjacent ends of said upper section at the top of said rack, at least one of the base section length or the base section width being greater than the respective upper section length or upper section width, at least a first, leg adapted to extend from said base section to said upper section and to support said upper section from said base section, said bag having a size corresponding to at least a 40-gallon US capacity when said bag is installed on said rack, said bag having a top edge, a bottom edge, and a generally continuous side wall extending from the lop edge to the bottom edge, a length of said bag generally extending along said side wall from the top edge to the bottom edge, said bag being closed at or adjacent the bottom edge of said bag, said bag being open about a full circumference of said bag at the top edge, thereby to define said bag as an open-top, closed-bottom receptacle adapted and configured to receive thin-section sheet material when mounted on said rack, an array of holes being distributed about the circumference of said bag, and extending along at least sixty percent of the length of said bag, said holes being located and sized so as to provide a hole open area, in the hole array, about the circumference and along the length of said bag, effective to facilitate escape of air from said bag during compression of said bag when said bag is filled with waste sheet material.
2. A combination as in claim 1, said bag being mounted on said rack with a lower portion of said bag extending inwardly of, and downwardly from, said upper section of said rack and with an upper portion of said bag: extending outwardly and downwardly over said upper section of said rack,
3. A combination as in claim 2 wherein the bottom of said bag is at or slightly above the bottom of said rack.
4. A combination as in claim 2, at least one of a friction element or point restrictor being mounted on said rack at a location where a weight in the bottom of said bag applies a stress in said bag at the top of said rack.
5. A combination as in claim 2, further comprising a friction element mounted to said rack at an elbow which extends from said at least one leg onto an arm which defines at least a portion of the top of said rack.
6. A combination as in claim 5 wherein said friction element comprises a rubber or plastic sleeve.
7. A combination as in claim 4, further comprising an array of point restrictors mounted: to said rack at a location where a weight in the bottom of said bag applies a stress in said bag at the top of said rack.
8. A combination as in claim 1 wherein said array of holes defines a hole fraction of 0.05% to 1% of a surface area of said sidewall of said bag.
9. A combination as in claim 1 wherein said array of holes defines a hole fraction of 0.07% to 0.5% of a surface area of said sidewall of said bag.
10. A combination as in claim 1 wherein said array of holes defines a hole fraction of 0.07% to 0.25% of a surface area of said sidewall of said bag.
11. A combination as in claim 10 wherein the holes in said array of holes are spaced apart by an average of at least 3 inches.
12. A combination as in claim 10 wherein the holes in said array of holes are spaced apart by an average of at least 4 inches.
13. A combination as in claim 10 wherein an average open area of the holes in said array corresponds to the area of a round hole having a diameter of at least 0.18 inch.
14. A combination as in claim 10 wherein an average open area of the holes in said array corresponds to an area of a round hole having a diameter of about 0.38 inch.
15. A plastic bag adapted and configured to be mounted to a rack wherein such rack has a base section defining a bottom of such rack, the base section being adapted to interface With an underlying support, an upper section of such rack being adapted to be disposed above such base section, the upper section defining a top of the rack, at least a first leg of the rack being adapted to extend from the base section to the upper section and to support the upper section from the base section, said bag having a top edge, a bottom edge, and a generally continuous side wall extending from the top edge to the bottom edge, a length of said bag generally extending at least 50 inches from the top edge to the bottom edge, said side wall having a thickness of about 1.25 mils to about 10 mils, said bag being closed at or adjacent the bottom edge of said bag, said bag having a fully open circumference of at least 64 inches at the top edge of said bag. thereby to define said bag as an open-top, closed-bottom receptacle adapted and configured to receive thin-section sheet material tossed loosely thereinto, when said bag is mounted to such rack, said bag having an array of holes distributed about the circumference of said bag, the array of holes extending along at least sixty percent of the length of said bag, such holes being located and sized so as to provide average hole open area, in the hole array, about the circumference and along the length of said bag, when said bag is filled with waste sheet material, and with said bag having been closed at such open top, effective to facilitate escape of air from said bag through said side wall during compression of said bag in a baler, while retaining such waste sheet material in the bag.
16. A plastic bag as in claim 15 wherein said array of holes defines a hole fraction of 0.05% to 1% of a surface area of said sidewall of said bag.
17. A plastic bag as in claim 15 wherein said array of holes defines a hole fraction of 0.07% to 0.5% of a surface area of said sidewall of said bag.
18. A plastic bag as in claim 15 wherein said array of boles defines a hole fraction of 0.07% to 0.25% of a surface area of said sidewall of said bag.
19. A plastic bag as in claim 15 wherein the holes in said array of holes are spaced apart by an average of at least 3 inches.
20. A plastic bag as in claim 18 wherein the holes in said array of holes are spaced apart by an average of at least 4 inches.
21. A plastic bag as in claim 18 wherein an average open area of the holes in said array corresponds to the area of a round hole having a diameter of at least 0.18 inch.
22. A plastic bag as in claim 15 wherein an average open area of the holes in said array corresponds to an area of a round hole having a diameter of about 0.38 inch.
23. A rack adapted and configured to receive and hold a bag while waste material is being placed in such bag, said rack comprising: (a) a base section defining a bottom of said rack, said bottom of said rack being adapted to interface with an underlying support, said base section further comprising a base section length, front-to-back, and a base section width, side-to-side, perpendicular to the base section length, (b) an upper section adapted to be disposed above said base section, said upper section defining a top of said rack, said ripper section having at least one arm defining an upper section circumference, the upper section circumference extending across any open spaces between next adjacent ends of said upper section at the top of said rack, at least one of the base section length or the base section width being greater than the respective upper section length or upper section width, (c) at least a first leg adapted to extend from said base section to said upper section and to support said upper section from said base section, and (d) at least one of a friction element or a point restrictor being mounted on said rack at a location where a weight in the bottom of such bag applies a stress in such bag at the top of said rack.
24. A rack as in claim 23, said rack having a height between the top of said rack and the bottom of said rack, further comprising a bag line marker on said first leg, said bag line marker being spaced from the top of said rack by a distance at least 10 percent as great as the height of said rack.
25. A rack as in claim 23, a said friction element being mounted to said rack at an elbow which extends from the at least one arm which defines at least a portion of the top of said rack, onto said at least one leg.
26. A rack as in claim 23, an elbow connecting said at least one leg with said at least one arm, said elbow having a radius of about 2.5 inches.
27. A rack as in claim 23, said at least one leg comprising first and second said legs, said first and second legs extending from said base section to said upper section, said legs being angled toward each other from said base section toward said upper section such that relatively upper portions of said legs are closer together than relatively lower portions of said legs.
28. A rack adapted and configured to receive and hold a bag while waste material is being placed in such bag, said rack comprising: (a) a base section defining a bottom of said rack, said bottom of said rack being adapted to interface with an underlying support, said base section further comprising a base section length, front-to-back, and a base section width, side-to-side, perpendicular to the base section length, (b) an upper section adapted to be disposed above said base section, said upper section defining a top of said rack, said upper section having an upper section length, front-to-back, an upper section width, side-to-side perpendicular to the upper section length, and one or more upper section arms defining an upper section circumference, the upper section circumference extending across any open spaces between next adjacent ends of said upper section arms at the top of said rack, at least one of the base section length or the base section width being greater than the respective upper section length or upper section width, (c) at least a first leg adapted to extend from said base section to said upper section and to support said upper section from said base section, and a rack height extending between the bottom of said rack and the top of said rack, and (d) a bag line marker on said first leg, said bag line marker being spaced from the top of said rack by a distance at least 10 percent as great as the height of said rack.
29. A rack as in claim 28, further comprising a friction element mounted to said rack at an elbow which extends from the at least one arm which defines at least a portion of the top of said rack, to said at least first leg.
30. A rack as in claim 28, an elbow joining said leg with at least one of said upper section arms, said elbow having a radius of about 2.5 inches.
31. A rack as in claim 28, said at least one leg comprising first and second said legs, said first and second legs extending from said base section to said upper section, said legs being angled toward each other from the base section toward said upper section such that relatively upper portions of said legs are closer together than relatively lower portions of said legs.
32. A rack as in claim 28, said bag line marker on said first leg being spaced from the top of said rack by a distance at least 20 percent as great as the height of said rack.
33. A method of processing thin-section waste material, comprising: (a) providing a rack, the rack having a base section defining a bottom of the rack, adapted to interface with an underlying support, an upper section disposed above the base section and defining a top of the rack, the upper section having one or more arms defining a circumference, the upper section circumference extending across any open spaces between next adjacent ends of such arms, at least a first leg extending from the base section to the upper section and supporting the upper section from the base section; (b) mounting, on the rack, a bag having a top edge, a bottom edge, and a generally continuous side wall extending from the top edge to the bottom edge, the bag having a closed bottom and an open top, and an array of holes distributed about the circumference of the bag and extending along the length of the bag, the holes being located and sized so as to facilitate escape of air from the bag during compression of the bag when the bag is filled with such thin-section waste material, a relatively lower port-on of the bag, when so mounted on the rack, being disposed inwardly of the circumference of the upper section of the rack, a relatively upper portion of the bag extending outwardly over, and downwardly from, the arms of the upper section; (c) placing a desired quantity of such thin-section waste sheet material in the bag; and (d) closing the top of the bag, thereby preventing such thin-section sheet material from leaving the bag.
34. A method as in claim 33, further comprising compressing the bag. containing such thin-section waste material, in a baler.
35. A method as in claim 34. comprising compressing multiple such bags, containing such thin-section sheet material, in such baler thereby obtaining a bale having a weight at least 10 percent greater than a weight of a bale of the same thin-section waste sheet material baled by placing loose such material in the same such baler without use of such bag.
36. A method as in claim 33 wherein the bottom of the bag is disposed at or slightly above the bottom of the rack when the such sheet material is first being placed in such bag.
37. A method as in claim 33, further comprising providing a such rack having at least one of a friction element or a point restrictor mounted on such rack at a location where a weight in the bottom of the bag applies a stress in the bag at the top of the rack.
38. A method as in claim 33, further comprising providing a such rack having a friction element mounted to the rack at a rack elbow, which rack elbow extends from the at least one leg onto an arm which defines at least a portion of the top of the rack.
39. A method as in claim 33, further comprising providing a such rack having one or more point restrictors mounted to the rack at a location where a weight in the bottom of the bag applies a stress in the bag at the top of the rack.
40. A method as in claim 33, further comprising providing such bag wherein the array of holes defines a hole fraction of 0.05% to 1% of a surface area of the sidewall of the bag.
41. A method as in claim 33, comprising providing suet; bag wherein the holes in the array of holes are spaced apart by an average of at least 3 inches.
42. A method as in claim 33, comprising providing such bag wherein an average open area of the holes in the array corresponds to the area of a round hole having a diameter of 0.38 inch.
43. A method as in claim: 33 comprising providing such rack having a bag line marker disposed on the first leg, and spaced downwardly from the top of the rack.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
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[0088] The invention is not limited in its application to the details of construction, or in the arrangement of the components, or in the specific methods set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments or of being practiced or carried out in ether various ways. Also, it is to be understood that the terminology and phraseology employed herein is for purpose of description and illustration and should not be regarded as limiting. Like reference numerals are used to indicate like components.
DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS
[0089] Referring to
[0090] Referring now to
[0091]
[0092] Rack 12 as illustrated is formed using hollow round steel tubing. Solid rod material can be used in place of tubing. Also, the cross-section configuration of the rack material can be other than round, such as square, rectangular, oval, or the like.
[0093] Referring now to
[0094] Rack 12 further has an upper section 34. Upper section 34 includes a top portion 35 which extends generally parallel to bottom portion 29. Upper section 34 includes downwardly depending leg leads 38 extending downwardly form third and fourth ends of top portion 35. Holes 38 extend through leg leads 38 proximate lower ends 39 of leg leads 36.
[0095] On each side of the rack, log elements 40 extend between the respective lower leg leads 30 and upper leg leads 36. Each of leg elements 40 has an upper constriction 42U and a lower constriction 42L. Such constrictions are reduced-diameter lengths of the respective leg elements. Cross-sections of leg constrictions 42U and 42L are sized so as to fit snugly into the ends 33, 39 of leg leads 30, 38. Holes 43 extend generally horizontally through the respective leg constrictions 42U, 42L near respective ends of the corresponding constrictions.
[0096] With leg constrictions 42U, 42L fully inserted into the respective leg leads 30, 36, holes 43 in the leg constrictions are aligned with holes 32, 38 in the respective leg leads. Spring-loaded pins 44 inside the leg constrictions extend through holes 43 in the leg constrictions and thence through respective holes 32, 38 in the respective leg leads.
[0097] Rack 12 has a rack front 48 which typically faces toward a worker as the worker is loading a bag mounted on such rack as illustrated in
[0098] Rack bottom 52 has opposing left and right side feet 56 and a rack rear foot 58 extending between the side feet. Rack top 50 has opposing left and right side arms 80 and a rear arm 62 extending between the side arms. Rack elbows 64 extend between side arms 60 and respective downwardly-extending legs 54, and connect the respective side arms with the corresponding legs.
[0099] Pins 44 in the leg constrictions and the corresponding leg leads stabilize the leg constrictions, and thus the leg elements, in the upper and lower leg leads, thus fixing the lengths of the legs, and correspondingly the height “H” of the rack, between the bottom 52 of the rack and the top 50 of the rack.
[0100] Structures and devices other than spring pins 44 and constrictions 42U, 42L can be used to removably or permanently secure leg elements 40 to base section 30 and upper section 34 in the process of assembling rack 12.
[0101] Sleeves 66, described in more detail hereinafter, are mounted to the rack at elbows 64, and extend generally from the top of the rack at side arms 60 to generally the top of the vertically downwardly-extending portions of legs 54. Sleeves 66 generally need not extend as far down as the ends 39 of upper leg leads 38.
[0102] A bag line marker 68 is positioned on each leg element, thus on each leg, well below the top of the rack. The bag line can be as simple as a line marking extending generally horizontally about at least a portion of the circumference of the leg. Typically, bag line marker 63 is a sticker or label which is adhesively mounted on the respective leg 54.
[0103] in an exemplary such rack, the rack height “H” is 53 inches from the bottom of the rack to the top of the rack, and bag line 68 is about 15 inches below the top of the rack. With the top of the bag folded down to the bag line as illustrated in
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[0105] One skilled in the art will realize that this invention also encompasses the use of other materials for the construction of rack 12, for example and without limitation, other metals such as aluminum, as well as plastic, rubber, wood, fiberglass composite materials, carbon fiber composites, and the like. Such other materials will inherently exhibit other coefficients of friction whereby the need for use of sleeves 66 may be altered or eliminated.
[0106]
[0107] Accordingly, mounting the bag on the rack begins with the worker moving the bag from the position shown in
[0108] With the bag adjacent the rear of the rack, the worker brings the top portion 74 of the bag downwardly and outwardly about the top of the rack, thus outwardly of, and about, side arms 80 and rear arm 62 as illustrated in
[0109] With the bag so installed on the rack, the circumference of the bag is such as to maintain a modest amount of circumferential stress/tension in the bag at the top of the rack as is inherent in the illustrated reduced bag cross-section at bag throat 78 at or adjacent top edge 74, below the top of the rack, in
[0110] While the specific distance between the top of the rack and the bag line marker 68 is not critical, the bag line markers are displaced far enough from the top of the rack that throat 78 is well developed below the top of the rack, inwardly toward the front of the rack from rear arm 62 of the upper section of the rack. Accordingly, the bag line marker is spaces from the top of the rack by a distance at least 10 percent, optionally at least 20 percent optionally at least 25 percent, as great as the overall height “H” of the rack.
[0111] The cross-section dimension of bag 14 is such that a modest amount of stress/stretch is imposed on the circumferential top portion of the empty bag as the bag is being engaged with the upper section of the rack during the mounting of the empty bag on the rack. Accordingly, once the rear side 80 of the top edge 76 of the empty bag passes downwardly past the side arms and rear arm of the rack, and with the front side 82 of the empty bag being engaged with the front of the rack e.g. at legs 54, and in the absence of any legs at the rear of the rack as illustrated in
[0112] With the bag so mounted on the rack, workers begin placing waste film or other thin-section material into bag 14. As waste material begins to accumulate in bag 14, the weight of the material in the bag begins to apply a downward gravitational force on bag 14.
[0113] The downward pull of the weight is resisted by the friction between the bag and the rack at the top of the rack. Particularly important is the friction contribution at sleeves 66. A friction enhancement is provided by the bag cross-section at throat 78. Namely, as weight/mass of waste material is added to the bag, and falls to the bottom of the bag, the weight of material in the bottom portion of the bag places a downward pull on the entire circumference of the bag material, including at throat 78. Given the angle a between vertical line “A”, and angled line “B” which extends from top edge 76 of the bag, the downward vertical force of the waste material weight applies a horizontal/outward force vector “C” which pulls the top edge of the bag outwardly toward the rear of the rack. Such outward force at the rear of top edge 76 thus adds to the bag forces already acting perpendicular to sleeves 88, thereby enhancing the ability of sleeves 88 to resist the tendency for the main body 84 of the bag to move downward in response to the weight of the waste material being placed into the bag.
[0114] When the bag has been filled, the worker 86 lifts the top portion 74 of the bag up above the top of the rack. The worker then closes off the top portion of the bag with any desired closure, for example an overhand knot or a zip tie, or other closure device, to prevent spillage of the collected waste material from the bag. With the filled bag so closed, the filled bag is removed from the rack and transported to a desired holding location, or to a baler,
[0115] Balers acceptable for use with the invention are available from e.g. Compactors Inc., Hilton Head, S.C. as vertical balers V630CC, V63HD, or V63XHD. Such balers are stated by the supplier to have 10 hp to 20 hp motors, hydraulic pump capacity of 10 gallons per minute to 15 gallons per minute, operating system pressure of 2000 pounds per square inch (psi) to 2200 psi, and maximum pressure of 2200 psi to 2500 psi, and are believed to produce platen pressure of about 34 psi to about 42 psi. Bales produced by such balers have dimensions of about 60 inches by 30 inches by 48 inches, thus bale volume of about 50 ft.sup.3, and weigh about 1000 pounds to about 1300 pounds.
[0116] In the alternative, the filled bag can be set aside for transportation to the baler, or to any desired holding location, along with additional filled bags, for example in order to better control transportation costs. For example, the bag may be placed in a Gaylord, and the Gaylord retained at the bag loading site until multiple filled bags have filled the Gaylord; whereupon the Gaylord is transported to the baler or other holding location.
[0117] Referring to
[0118] The rack size in the embodiment illustrated in
[0119] Thus, rack top 50 as illustrated in e.g.
[0120] Further, the base section of the rack can be made of a more massive, more dense, or heavier material than the upper section. For example, the base section can be formed using solid rod steel or aluminum while the upper section is formed using tubular steel or aluminum. Further, the rack can be made from square solid rod or hollow tubing, or metal having a U-shaped cross-section sometimes referred to as “channel iron”, or a right angle cross-section commonly referred to as “angle iron”.
[0121] In the embodiments illustrated in
[0122] The cross section of the rack can be solid or hollow, and the rack can contain various wall thicknesses within a given cross section or along the length of a rack section. The shape of the cross section of the rack elements, e.g. upper section, bottom section, and/or leg sections, can be circular, square, rectangular, elliptical, triangular, or other shapes, and the cross-section can vary in size and shape along the length of the structure while accommodating any or all of the structures shown in (
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[0124] The portion of rack 12 or 92 which contacts the floor may be left bare, or may be painted or otherwise coated. Rack 12 can have feet, wheels, sliders, or other components to hold the rack in place, to level the rack, or to enable the rack to move relatively easily to and from any desired location.
[0125] The Bag
[0126] Bag 14 is designed to receive and hold recyclable thin-section materials such as paper or thin-section plastic film. In one embodiment, the bag, itself, is made from low density polyethylene, also known as LDPE, and is used to store recyclable materials made from the same material, namely LDPE, recognizing that the acronym LDPE represents a lame family of polymers having different structures and properties, though the structures and properties are generally similar. As desired, other materials can be used for the bag including woven cloth, other plastics, rubber, etc., and combinations of materials can be used within a given bag. In general, the material used tor the bag is desired to have the same composition as the material which is expected to be placed in the bag for recycling so that the value of the entire bag. including both the bag, itself, and the bag contents, is maximized. In such instance the total shipment, namely bag plus bag contents, can be received at the recycling center with the aim of processing/recycling both the bag material and the bag contents as one charge of recyclable material, to obtain a recycled product having a high fraction of a common polymeric composition or very similar compositions.
[0127] In some embodiments, the bag is clear/transparent, enabling a user to see through the bag wall, thus to view the materials placed inside the bag. Such transparency helps a user to inspect the bag contents periodically in order to avoid placing an inappropriate mix of materials in the bag during the bag filling process. However, other bag colors and opacities are contemplated as being useful in some embodiments of the invention.
[0128] Whatever the rack size and configuration, the bag is sized and configured to fit the rack and to enable easy mounting of the bag onto the rack and removal of the bag from the rack, while imposing enough stress in the bag at the top of the rack, while the bag is being mounted on the rack, to enable the bag to remain in place, mounted on the rack, while the weight of waste being placed into the bag pulls down on the bag. Given the flexibility of the bag material, and in light of the disclosure herein, bags can be configured for cooperative operation with all of the rack shapes depicted in
[0129] Bags 14, themselves, are typically made of plastic film extruded through a circular die. Bag wall thickness is typically generally constant about the circumference and length of the bag. according to thickness consistencies which can be achieved in conventionally-practiced extrusion processes. As desired, bag wall thickness can be intentionally varied e.g. to increase strength only where needed while minimizing material usage. For the uses illustrated herein, and assuming a composition dependent primarily on ethylene-based polymers such as LDPE or LDPE-based polymers or copolymers, and assuming constant bag wall thickness, typical bag wall thickness is about 1.25 mils to about 10 mils, optionally about 1.6 mils to about 6 mils, optionally about 2 mils to about 4 mils, optionally about 2 mils. A bag having a 2-mil wall thickness is satisfactory to hold as much of the volume of recyclable plastic film scrap as most end users are able to get into a bag having a height “H” of about 53 inches, and adapted to be mounted on a rack such as that illustrated in
[0130] The bag, as produced, is a flat collapsed bag, which may be folded longitudinally on itself for packaging and/or shipping as illustrated in
[0131] Given that the intended use of the bag is to receive thin-section waste material, whether paper, plastic, or other thin-section material, it is known that such thin-section waste materials are quite flexible. Given that the material is considered waste material, little effort is made by workers who retrieve, pick up, clean up, such waste material, to preserve any particular configuration for such material, or to closely pack such waste material while placing the waste material into bag 14. Rather, since waste material has only limited monetary value, priority is typically given to disposing of. processing, such waste material with as little labor as possible. Accordingly, workers are typically instructed to dispose of the waste material by simply placing as much of such material as possible into an available waste receptacle, with no regard for the configuration of the waste material the waste receptacle.
[0132] As used herein, the phrase “sheet material” generally refers to plastic films and sheets, and sheets of paper. Films are generally rip to 10 mils thick, including stretch films, shrink films, non-stretch films, and non-shrink films. Sheets are generally plastic materials greater than 10 mils thick, or paper.
[0133] Typically, where the wall thickness of bag 14 is up to 10 mils, the plastic pieces placed in the bag can be up to about 50 mils thick. Considering thicker waste plastic pieces, especially where the thickness is over 50 mils, there is a risk that the waste pieces may penetrate the bag walls. Accordingly, bags used to receive such thicker waste pieces have wall thickness greater than 10 mils. Those skilled in the art will be able to determine the necessary wall thickness for such bags. However, the wall thickness of the bag cannot be so great that the bag cannot be effectively collapsed in the baler with release of substantially all air from the bag. If is recognized, however, that the forces used in typical industrial commercial balers are unlikely to expel, release, 100% of the air inside the bag when the filled bag is compressed in the baler.
[0134] Returning now to discussion of recycling of typical flexible waste material, such flexible waste material may be inherently folded, bent, or the like during the process of being thrown, tossed, or placed casually into the bag. By “placed casually” is meant that the worker makes little or no effort to configure the waste material in the receptacle in order to enhance the bulk density of the material in the receptacle. Rather, the worker typically moves pieces of the waste material to the top of the open bag, as mounted on the rack, and allows the material to fall into the bag/receptacle in a random, uncontrolled arrangement.
[0135] Where the waste material is in the form of small consistent-dimension sheets or films, such sheets or turns may be placed, thrown into the receptacle by the handful. A larger piece of waste material may be folded, typically loosely folded, as it is being placed into the receptacle, in order that the large piece have a small enough bulk, 3-dimensional cross-section to be placed into the receptacle. For example, where a large protective piece of shrink wrap plastic film is removed from a skid of product, the piece of plastic film may have length and/or width dimensions larger than the opening in the waste receptacle. Such large piece may be folded or loosely rolled up or otherwise configured as the piece of waste material is being placed into the receptacle. In some instances, the waste material may consist of irregularly-shaped sheets or films, for example scrap film generated during the start up or shut down of an extrusion process. Such waste material may vary in size and shape from piece to piece.
[0136] Whatever the size or shape of the waste material, whether film or sheet, the waste material placed info receptacles/bags 14 of the invention typically occupies only a small fraction of the gross space contained within the walls of the bag. The remainder of the gross space is occupied by air.
[0137] One of the challenges in recycling waste thin-section materials is that such thin-section waste materials, as collected, have low bulk densities. Typically, waste materials must be transported to a location where the waste materials can be processed for conversion into new and useful products. But the cost of transporting such low-value materials in low bulk density form is unacceptably high. Thus, it is critical to be able to compress such waste materials, thus to increase bulk density, by removing air from the materials so compressed, in order that transportation costing be correspondingly improved.
[0138] Polymers typically have densities in the range of about 0.83 to about 2.15. Polymers in plastic film materials contemplated to be most commonly recycled using the invention are polyolefins, which typically have densities of about 1.0 or less, commonly between about 0.86 and about 0.95. While recycling films or sheets of polyolefins is contemplated as the most common use of the invention, recycling of other waste polymer compositions is also within the scope of the invention so long as snob waste material is a thin-section material which enters bag 14 as a generally low bulk density material.
[0139] While materials having relatively greater bulk density can be loaded into the bag, a potentially greater respective weight in the bag may suggest respectively greater bag wall thickness and/or different polymer selection and/or multiple layers of different polymer compositions for the bag side wall in order to accommodate the e.g. tensile strength of the bag side wall to fine load to be carried in the bag.
[0140] While rack 12 is focal to holding bag 14 in place while the bag is being filled, reducing the amount of air in the bag, and thus increasing the bulk density of the waste material contained within the bag, is also critical to the invention.
[0141] To that end, holes 16 are formed in the bag, typically while the bag is flat as shown in
[0142] To that end, in the above embodiment where the bag is 80 inches tall and 44 inches wide, 104 holes 16, each ⅜ inch in diameter, are formed in the bag such as by the use of one or more mechanical punches. Preferably, but not necessarily, the holes are clear of hanging chads or flaps.
[0143] In the illustrated embodiments in
[0144] To that end, the hole fraction of the wall, namely the fraction of the bag wall area represented by the holes can be from about 0.05% to about 1%, optionally about 0.07% to about 0.5%, optionally 0.07% to about 0.25%.
[0145] Configurations of the individual holes can be round, oval, oblong, or otherwise elongated, can have bends, corners, and the like. Such holes can be regular polygons, irregular polygons, and any of a wide variety of cross-section shapes.
[0146] In preferred embodiments, all of the material outlined by the hole is removed from the hole as the hole is being formed. In some instances, the punch/die used in forming the hole is designed to leave the punched-out portion of bag wall material attached, as a hanging chad, at a single location about the otherwise complete circumference of the hole. In some embodiments, material is left uncut at two locations about the circumference of the hole, typically opposite each other across the hole, thus creating two hole elements, and leaving two hanging chads for each hole Leaving the one or more chads attached at. the hole circumference provides the benefit of eliminating much of the litter of punched-out hole pieces at the punching work station, and provides for recycling, along with the bag, of the pieces punched out of the bag wall at the holes.
[0147] On the other hand, leaving hanging chads at the holes enables the chads to move into some of the hole passages as the air is being urged to escape from the bag during baling. Thus, the less the attached hole material at the holes, the easier it is for air to escape as the bag is being compressed in the baler, thus to obtain a bale having a relatively higher bulk density.
[0148] For purposes of ease of removing air from the bag, the bag wall material inside the area punched by an individual punch in making a hole can be completely removed while making the holes because, when a flap/chad of material is left attached to the hole, the hole does not work as well for removing air from the bag during baling as does a similar size hole, in a similar hole-pattern, where the flap/chad has been removed from the area of the hole. Thus, where chads are contemplated, a relatively larger hole size is typically specified in order to enable removal of a contemplated amount of air during compression in the baler.
[0149] Hole size, shape, spacing, and arrangement patterns can be varied within the scope of the invention. Assuming a round, circular hole, hole size can range from 0.03 inch diameter to about 0.75 inch diameter, optionally about 0.13 inch to about 0.6 inch, optionally 0.25 inch to about 0.4 inch with the number of holes varying correspondingly to provide for a hole fraction at least one third as great as the hole fraction inherent in the above example of 104 holes each ⅜ inch diameter, and a hole fraction no more than 7 times as great as the respective example. Again, hole size, and hole fraction, depend on the make-up, including physical properties, of the recyclable material to be placed in the bag.
[0150] Relatively smaller size recyclable material pieces require relatively smaller holes. Relatively larger size recyclable material pieces suggest relatively larger holes conditioned, however, on the surface characteristics of the waste material. For example, waste material which tends to adhere to itself or to the material of the wall of the bag, e.g. by surface properties or chemical adhesion, requires an additional consideration of hole size, hole fraction, and hole spacing in order that the contained recyclable material not unacceptably obstruct the holes and thus hinder the air from exiting the bag through the respective holes. What is important is that the air contained in film or other waste inside the bag be able to move, under compression from the baler, to and through the holes in the bag wall.
[0151] The arrangement of the holes can be any of a variety of hole patterns such as the hole pattern illustrated in
[0152] The shape of any given hole can be configured to optimize bag strength. Thus, the hole can be a circle, a slot, a slit, or oblong, or star-shaped, or any other desired shape, if desired some or all of the holes can be reinforced with one or more additional layers of material, the reinforcing material being limited in area, to surrounding only a hole or a cluster of holes. Such hole reinforcement is defined only about the holes and only with respect to no more than about five percent of the surface area of the bag material.
[0153] Typically, the holes are spaced apart an average of at least about 3 inches, optionally at least about 4 inches, optionally at least about 5 inches, with each hole being within at least 18 inches, optionally 15 inches, of another hole. The arrangement of the hole array need not be square, need not be rectangular, need not be diamond shaped, though all such arrangements are acceptable. As illustrated in
[0154] Attachment of the Bag to the Rack
[0155] Gravity, and friction between the bag and the rack, may be the primary forces holding the bag in place To that end, properly contoured rack, bends and rubber sleeves can assist in holding the bag in place. Where the bags is 2 mils thick, 80 inches high, 88 inches around at the top edge, where the rack is 53 inches high. 24 inches square at the top, 28 inches square at the bottom, where the holes are ⅜ inch diameter and spaced in a 6×10 inch linear/columnar matrix, where the rack bends at the top of the rack, front and rear, are 2.5 inches radius, the respective system works quite satisfactorily to receive thin-section waste LDPE film. Substantially smaller radius tends to overstress an almost-fully-loaded bag at the upper corners of the rack. Where the radius is substantially greater, an almost-fully-loaded bag tends to slip downwardly on the rack. However, any potential deficiency in rack radius, whether relatively greater or smaller, can be resolved by adding a longer sleeve 66, or by adding sleeve material or other friction material at additional locations on the top of the rack. Alternatively, the bag may contain strings, belts, flaps, buttons, Velcro, etc. with or without the use of clips, pins/posts, and slots on the rack, to help keep the bag in place during loading. Also as the rack size or surface properties are changed, the bag configuration and/or the friction sleeves or other friction elements on the rack may need adjustment/modification in order to maintain the bag mounted on the rack while the bag is being filled with waste material.
[0156] Friction sleeves 60 at front elbows 64 of the upper section of the rack are designed to keep bag 14 from tearing, or slipping off the rack, during loading of recyclable material info the bag. Sleeves 66 can enclose all or a portion of the circumference of the cross-section of the rack at the respective elbow. Sleeves can be made from any material such as for example and without limitation, cork, plastic, rubber etc., and any of a wide variety of textured surfaces which have surface friction greater than the surface friction of the e.g. powder-coated rack tubing itself. One such acceptable sleeve material is a foamed neoprene rubber tube. Such neoprene rubber tube has a nominal inner diameter the same dimension as the rack tubing, and a wall thickness about 10-15% as great as the inner diameter. Thus, where the rack tubing has an outside diameter of e.g. 1 inch, sleeve 66 has an inner diameter of about 1 inch and an outer diameter of about 1.25 inches.
[0157]
[0158]
[0159]
[0160] Another primary method of functioning for protuberances 100 is for the protuberances to extend sufficiently from the rack to act as point restrictors, optionally in combination with friction properties of the protuberances,
[0161] In the alternative, the retainer structure can be fabricated in strip form. Such strip retainer can then be simply cut to length, the peelable layer 108 is removed, and the adhesive layer 110 is used to adhesively mount the strip to the rack tubing at a location where the bag will encounter substantial stress during loading of the bag with waste material. Any desired number of strips can be mounted to the rack in order to achieve bag stability while the bag is being loaded with waste material.
[0162] In some embodiments, the retainer strip can be fabricated as a roll of such retainer. In such instance, peelable layer 108 is obviated such that adhesive layer 110 is directly adjacent an underlying layer of the multiple-layer structure in the roll and in contact with, contacting, the underlying protuberance layer. Thus, just as one unrolls a length of any tape in order to obtain a desired length of such tape, so such multiple-layer retainer structure can be stored in roll form, and unrolled and cut, to directly expose adhesive layer 108. which can then be applied to the rack tubing.
[0163] In
[0164] In
[0165] As illustrated in
[0166]
[0167]
[0168] In
[0169] In
[0170] In an embodiment not shown, protuberances 100 of
[0171] The protuberance properties illustrated in
[0172] While protuberance properties have been illustrated for elements which are mounted to the rack material, it is also contemplated that the rack material, in this case rack metal tubing, can be similarly modified so as to exhibit either friction properties, or point restrictors, or both. In addition, various coating materials can be applied as thin film coatings, e.g. “painted” on the rack tubing ;n order to impart friction-based properties to the rack tubing, either alone, or in combination with point restrictors fabricated into the surface of the rack tubing. Such coatings may be relatively smooth and thereby operate primarily on the basis of friction properties or may include point restrictors such as e.g. sand particles so as to operate at least in part as point restrictors.
[0173]
[0174]
[0175] Holes 16 in the bag enable air to escape through the side walls and end walls of the bag while the bag, or bags, is/are being compressed during compaction in the baler. Because the air can easily escape from the bag, through the holes in the bag side walls and end wall during baling, a greater fraction of the air can be removed from the bag for a given compaction force whereby a bale of such) e.g. plastic film, can contain about 10% to about 25% more weight/mass of the film or other thin-section waste material than a traditional bale made with the same baler conditions, without use of the invention. Because a bale made according to the invention has more mass, and fewer bales are needed for disposing of a given mass of waste material. Fewer bales means relatively less labor cost, greater waste material weight per truckload shipped to a recycling center, thus fewer truckloads and associated relatively lower shipping cost. In addition to the greater efficiency in weight capacity enabled by this invention, workers no longer need to bend, lift, and twist hundreds of times to retrieve loosely-arranged pieces of e.g. plastics film from the bulk box and place them into the baler, thus improving the ergonomics of the work environment by reducing the risk of repetitive motion injury.
[0176] As used herein, recyclable materials being loaded into the bag can include such materials as shrink wrap, foam, and bubble wrap, which are typically LDPE, medical blue wrap which is typically polypropylene (PP), material used for banding, which may be e.g. PP or polyethylene terephthalate (PET), paper, styrofoam/polystyrene, laminates of various plastics and plastic/paper composites. Other materials, typically low bulk density materials, which trap or contain large quantities of air, can be placed in the bag and still fall within the scope of this invention.