US5060870A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Polystyrene recycling process
Assignee: WTE Corp
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Filing: 1990-08-03
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Granted: 1991-10-29
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Expires: 2010-08-03
Abstract
Abstract The invention comprises a method and apparatus for recycling foamed polystyrene from municipal solid waste and more particularly, from fast food restaurant waste. A steady stream of waste is delivered to a flail mill for reducing particle size, a rotary trommel for eliminating undersized waste and a rotary air classifier for removing "heavy" waste from the stream. At this point, the waste stream comprises mostly paper and foamed polystyrene. The paper and foamed polystyrene are delivered to a water pulper which fiberizes the paper so that it can then be separated from the foamed polystyrene by passing it through a screen of selected mesh size to allow the water and paper pulp to pass through while retaining the foamed polystyrene.
Inventors
- 👤 George Trezek
- 👤 Martin Stanczyk
- 👤 Michael Grubbs
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 18:37
CPC Classifications
B; B29; B29B; B29B17/00; B29B17/02; B29B13/00; B29B13/10; B29B2017/0203; B29B2017/0213; B29B2017/0217; B29B2017/0251; B29K; B29K2025/00; B29K2025/04; B29K2025/06; B29K2105/00; B29K2105/04; B29K2105/06; B29K2105/065; B29K2705/00; B29K2711/00; B29K2711/12; B29L; B29L2031/00; B29L2031/712; B29L2031/7158; Y; Y02; Y02W; Y02W30/00; Y02W30/50; Y02W30/62; Y10; Y10S; Y10S209/00; Y10S209/93; Y10S241/00; Y10S241/38
Claims Analysis
Total Claims: 38
Claim 1
Independent Claim
149 words
A method of recovering waste particles having a fluidization velocity less than a predefined fluidization velocity, said waste particles termed low FV particles, from a stream of waste, said stream of waste comprising low FV waste particles mixed with other types of waste including waste particles having a fluidization velocity greater than said predefined fluidization velocity termed high FV particles, said method comprising the steps of; a. reducing the waste to particle sizes within a first range of sizes, b. subjecting the stream of waste particles to an air stream having a velocity sufficient to carry low FV particles while high FV particles are not carried by and are thereby eliminated from the stream of waste particles, c. mixing the stream of waste particles with water, d. agitating the mixture to fiberize any paper particle waste therein contained, and e. removing the fiberized particles and water from the stream.
Claim 2
Independent Claim
149 words
A method of recovering waste particles having a fluidization velocity less than a predefined fluidization velocity, said waste particles termed low FV particles, from a stream of waste, said stream of waste comprising low FV waste particles mixed with other types of waste including waste particles having a fluidization velocity greater than said predefined fluidization velocity termed high FV particles, said method comprising the steps of; a. reducing the waste to particle sizes within a first range of sizes, b. subjecting the stream of waste particles to an air stream having a velocity sufficient to carry low FV particles while high FV particles are not carried by and are thereby eliminated from the stream of waste particles, c. mixing the stream of waste particles with water, d. agitating the mixture to fiberize any paper particle waste therein contained, and e. removing the fiberized particles and water from the stream.
Claim 3
Dependent Claim
17 words
A method as set forth in claim 1 wherein said low FV waste is a foamed plastic.
Claim 4
Dependent Claim
15 words
A method as set forth in claim 2 wherein said foamed plastic is polystyrene foam.
Claim 5
Dependent Claim
52 words
A method as set forth in claim 3 wherein step (a) comprises the steps of shredding said waste to reduce the waste particles size to a predefined maximum size, and passing the stream of waste particles over a screen having openings sized to remove waste particles smaller than a predefined minimum size.
Claim 6
Dependent Claim
27 words
A method as set forth in claim 4 wherein said screen is formed into a cylindrical trommel and said trommel rotates as said waste particles pass through.
Claim 7
Dependent Claim
44 words
A method as set forth in claim 1 wherein said stream of waste comprises plastic bags within which waste particles are contained and wherein the step of shredding said waste tears open said plastic bags and liberates waste particles contained within said plastic bags.
Claim 8
Dependent Claim
27 words
A method as set forth in claim 6 further comprising the step of removing said plastic bags from the stream of waste directly after said shredding step.
Claim 9
Dependent Claim
29 words
A method as set forth in claim 7 wherein waste particles which are removed from said stream of waste in steps a and b are formed into densified refuse-derived-fuel.
Claim 10
Dependent Claim
70 words
A method as set forth in claim 8 wherein the process of forming said refuse derived fuel comprises the steps of; combining the removed waste from steps a and b to form a secondary stream of waste, shredding said secondary stream of waste to produce secondary waste particles of a second predefined size range, compressing said secondary waste particles, extruding said compressed waste particles into pellets, and cooling said pellets.
Claim 11
Dependent Claim
25 words
A method as set forth in claim 9 further comprising the step of de-watering the removed fiberized particles from step e to produce paper pulp.
Claim 12
Independent Claim
213 words
A method of recovering foamed polystyrene waste particles from a source of waste particles primarily comprising paper products, wax coated paper products and foamed polystyrene, comprising the steps of; a. shredding said waste so as to reduce the size of the particles of said waste to a first predefined maximum particle size and to open any bags in said waste stream, b. delivering said waste to a rotary trommel having openings of a second specified size so as to remove waste particles which are smaller than a second specified size from the waste stream, c. introducing said waste to an air chamber having an air flow velocity therein that will cause waste particles having a fluidization velocity below a specified fluidization velocity to be carried through said chamber by said air flow while waste particles having a higher fluidization velocity than said specified fluidization velocity are not carried by said air flow, said fluidization velocity being higher than the fluidization velocity of foamed polystyrene, d. introducing the waste which passes thorugh said chamber into a mixing vat, e. mixing said waste particles with water, and f. passing the mixture through a screen of a specified mesh size that will allow water and paper pulp to pass through while retaining the foamed polystyrene particles.
Claim 13
Independent Claim
213 words
A method of recovering foamed polystyrene waste particles from a source of waste particles primarily comprising paper products, wax coated paper products and foamed polystyrene, comprising the steps of; a. shredding said waste so as to reduce the size of the particles of said waste to a first predefined maximum particle size and to open any bags in said waste stream, b. delivering said waste to a rotary trommel having openings of a second specified size so as to remove waste particles which are smaller than a second specified size from the waste stream, c. introducing said waste to an air chamber having an air flow velocity therein that will cause waste particles having a fluidization velocity below a specified fluidization velocity to be carried through said chamber by said air flow while waste particles having a higher fluidization velocity than said specified fluidization velocity are not carried by said air flow, said fluidization velocity being higher than the fluidization velocity of foamed polystyrene, d. introducing the waste which passes thorugh said chamber into a mixing vat, e. mixing said waste particles with water, and f. passing the mixture through a screen of a specified mesh size that will allow water and paper pulp to pass through while retaining the foamed polystyrene particles.
Claim 14
Dependent Claim
43 words
A method as set forth in claim 11 further comprising the step of agitating said mixture before passing it through said screen so as to facilitate the breakdown of the paper in said mixture to paper pulp and to cleanse the foamed polystyrene.
Claim 15
Dependent Claim
34 words
A method as set forth in claim 12 wherein said waste includes plastic liners and further comprising the step of removing said plastic liners from the stream of waste between step b and c.
Claim 16
Dependent Claim
28 words
A method as set forth in claim 13 wherein the stream of waste primarily comprises paper products, plastic eating utensils, wax coated paper products and foamed polystyrene products.
Claim 17
Dependent Claim
33 words
A method as set forth in claim 14 wherein waste particles which are removed from said stream of waste in steps a and c are combined and formed into densified refuse derived fuel.
Claim 18
Dependent Claim
21 words
A method as set forth in claim 15 further comprising the step of de-watering the removed paper pulp from step f.
Claim 19
Dependent Claim
40 words
A method as set forth in claim 16 further comprising the steps of; passing the water and paper pulp through a sieve to separate said water from said paper pulp, and recovering said water for use again in step e.
Claim 20
Independent Claim
139 words
An apparatus for recovering foamed polystyrene from waste, said waste comprising foamed polystyrene waste particles mixed with other types of waste particles said apparatus comprising: means for conveying a continuous stream of waste through said apparatus, means for reducing the size of said foamed polystyrene and other waste particles to a first predetermined size range and to tear open any bags in which waste particles may be contained at an initial station along said stream, means for removing from said stream of reduced particles, particles that have a higher fluidization velocity than a specified fluidization velocity, means for mixing said waste with water to fiberize any paper remaining in said waste stream after removal of said high fluidization velocity particles, and means for separating said foamed polystyrene particles from said waste stream after fiberization of paper in said stream.
Claim 21
Independent Claim
139 words
An apparatus for recovering foamed polystyrene from waste, said waste comprising foamed polystyrene waste particles mixed with other types of waste particles said apparatus comprising: means for conveying a continuous stream of waste through said apparatus, means for reducing the size of said foamed polystyrene and other waste particles to a first predetermined size range and to tear open any bags in which waste particles may be contained at an initial station along said stream, means for removing from said stream of reduced particles, particles that have a higher fluidization velocity than a specified fluidization velocity, means for mixing said waste with water to fiberize any paper remaining in said waste stream after removal of said high fluidization velocity particles, and means for separating said foamed polystyrene particles from said waste stream after fiberization of paper in said stream.
Claim 22
Dependent Claim
35 words
An apparatus as set forth in claim 18 wherein said means for reducing comprises, means for shredding said waste, and means for eliminating from said waste stream waste particles smaller than a first predefined size.
Claim 23
Dependent Claim
38 words
An apparatus as set forth in claim 19 wherein said means for shredding comprises a flail mill having a chamber into which said waste is delivered, and a plurality of rotating hammers for contacting and shredding said waste.
Claim 24
Dependent Claim
29 words
An apparatus as set forth in claim 20 wherein said means for eliminating comprises a rotating, cylindrical trommel constructed of a screen having holes of said first predefined size.
Claim 25
Dependent Claim
13 words
An apparatus as set forth in claim 21 wherein said screen is vibrated.
Claim 26
Dependent Claim
133 words
An apparatus as set forth in claim 20 wherein said means for removing high fluidization velocity waste particles comprises an air classifier having, a cylindrical air chamber aligned on an incline and having a lower end for accepting waste and an upper end for discharging waste, means for forcing air through said chamber towards said upper end at a velocity that will carry waste particles having a fluidization velocity less than said specified fluidization velocity through said chamber yet allow waste particles having a higher fluidization velocity than said specified fluidization velocity to settle in said chamber, the incline of said chamber assisting said settled waste to fall out of said lower end of said air chamber and said specified fluidization velocity being greater than the fluidizaton velocity of said foamed polystyrene particles.
Claim 27
Dependent Claim
41 words
An apparatus as set forth in claim 23 wherein said air classifier further comprises, means for rotating said air chamber, baffles disposed on the inner wall of said chamber to contact the waste particles and expose them to the air stream.
Claim 28
Dependent Claim
68 words
An apparatus as set forth in claim 24 wherein said air classifier further comprises a plenum chamber coupled to receive waste particles from the upper end of said air classifier, said plenum chamber having a cross-section larger than said air classifier so as to reduce the velocity of the air to a velocity that allows the carried waste particles to settle to the bottom of said plenum chamber.
Claim 29
Dependent Claim
31 words
An apparatus as set forth in claim 18 further comprising means for agitating said waste/water mixture before passing through said screen so as to assist in the fiberization of said paper.
Claim 30
Dependent Claim
62 words
An apparatus as set forth in claim 18 wherein said means for mixing said waste with water comprises a batch pulper including a mixing chamber, means for delivering a specified amount of waste from said air classifier, means for introducing water into said mixing chamber, an agitator for mixing said waste and water, and means for pumping said mixture towards said screen.
Claim 31
Dependent Claim
17 words
An apparatus as set forth in claim 27 wherein said means for delivering comprises a conveyor belt.
Claim 32
Dependent Claim
63 words
An apparatus as set forth in claim 18 wherein said means for mixing said waste with water comprises a continuous pulper including, means for continuously delivering said waste from said air classifier to said mixing chamber, means for continuously delivering water to said mixing chamber, and an agitator in said chamber for shredding said waste and forcing the mixture toward said output end.
Claim 33
Dependent Claim
59 words
An apparatus as set forth in claim 29 further comprising, means for receiving and transporting said waste particles smaller than said first predefined size, means for receiving and transporting said high fluidization velocity waste particles, means for mixing said high fluidization velocity waste particles with said smaller waste, and means for pelletizing said mixed waste to produce densified refuse-derived-fuel.
Claim 34
Dependent Claim
18 words
An apparatus as set forth in claim 30 wherein said means for receiving and transporting comprise conveyor belts.
Claim 35
Dependent Claim
75 words
An apparatus as set forth in claim 18 further comprising a sieve coupled to receive the water and paper which passes through said means for separating said waste stream after fiberization, said sieve comprising a mesh of a size sufficient to separate said water from said paper pulp, and means coupled to receive said water through said sieve, and means for pumping said water from said means to receive back into said means for mixing.
Claim 36
Dependent Claim
40 words
An apparatus as set forth in claim 18 wherein said means for separating said waste stream after fiberization comprises a screen having a mesh size which will allow water and paper pulp to pass through and retain foamed polystryene particles.
Claim 37
Independent Claim
122 words
A method of separating foam plastic waste from a quantity of mixed waste which may include paper, waxed paper, food, plastic utensils, bags, cups and plates comprising the steps of; entraining said waste into a stream of waste, sequentially treating said waste stream at a series of stations to reduce the waste stream to particles within a predetermined range of sizes, thereafter removing all but light weight particles including said foam plastic from the stream by directly blowing air through the stream by means of an air current which continues to carry only the light weight particles in the stream, thereafter fiberizing the light weight particles other than the foam plastic in a water matrix, and separating the foam plastic particles therefrom.
Claim 38
Independent Claim
122 words
A method of separating foam plastic waste from a quantity of mixed waste which may include paper, waxed paper, food, plastic utensils, bags, cups and plates comprising the steps of; entraining said waste into a stream of waste, sequentially treating said waste stream at a series of stations to reduce the waste stream to particles within a predetermined range of sizes, thereafter removing all but light weight particles including said foam plastic from the stream by directly blowing air through the stream by means of an air current which continues to carry only the light weight particles in the stream, thereafter fiberizing the light weight particles other than the foam plastic in a water matrix, and separating the foam plastic particles therefrom.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-10-28 | 1995-04-29 | 1995-10-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-10-28 | 1999-04-29 | 1999-10-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-10-28 | 2003-04-29 | 2003-10-29 | $7700.00 | Window Closed / Lapsed |