WO1990010506A1

WO1990010506A1 - Particle separation and classification mechanism

Info

Publication number: WO1990010506A1
Application number: PCT/US1990/001046
Authority: WO
Inventors: Kenneth Edward Abbott; Patrick James Lyons
Original assignee: Stripping Technologies Inc.
Priority date: 1989-02-27
Filing date: 1990-02-26
Publication date: 1990-09-20
Also published as: AU5274390A

Abstract

A particle separator which separates particles based upon their relative densities or weights. The mixture of particles (108) is deposited within a gas channel (101) while a flow of gas (107a-d), created by a gas flow amplifier (103), separates the material. The gas flow is sufficient to entrain the lighter/less dense particles; but is insufficient to entrain the heavier particles which are allowed to fall into a receptacle (113). The lighter entrained particles are directed to another receptacle or container (106).

Description

PARTICLE SEPARATION AND CLASSIFICATION MECHANISM

Baclug round t

This invention relates generally to parti cle separati on and , more particularly , to particle separation based upon the relative densi ties or weights of the particles involved. The separation of a useful product from an unusable i tem has plagued man almos from the dawn of time. In f act, the early form of threshing wheat, using the wind to blow away the chaff , is one such soluti on to the problem.

As the industrialization of the world took place, the separation of par ticles became a more intense problem since the materials s ought were needed in higher concentrations than before .

Separating a flui d mixture has posed some very unique problems. With these problems , some unique solutions have been developed such as United States Patent Number 4 ,539,103, entitled "Hydraulic Separating Method and Apparatus" issued September 3,

1985, to Hollingworth; and United S tates Patent Number 4,176,749, entitled "Materials Separation" issued December 4, 1979, to Wallace et al. In both of these inventions, the material that is to be separated is suspended in a liquid which is uti lized for the extraction of the material.

Unfortunately, the abilities and expertise of liquid seperators are not easily ported over to a mixture of dry material. In attempting to solve this problem, a wide variety of fluidized beds have been developed including: United States

Patent Number 4,194,971, entitled "Method of Sorting Fluidized Parti culate Material and Apparatus Therefor" issued March 25, 1980, to Beeckmans; and United States Patent Number 4,546,552, entitled "Fluid Induced Transverse Flow Magnetically Stabilized Fluidized Bed" issued October 15, 1985, to Cahn et al .

In all fluidized bed separation situations, the mixture to be separated is suspended on a grate or bed while air "bubbles" through the mixture at a rate sufficient to remove a targeted particle permitting the remaining material to be swept away or to fall through the grate. Balancing the inflow of contaminated mixture to the throughput is extremely difficult. Without this control though, the mechanism does not perform optimally.

The problem of control is of such a concern that a whole group of inventions address this problem alone. One such invention is described in United States Patent number 4,248,702, entitled "Stratifier Discharge Control" issued February 3, 1981, to Wallace et al.

Even though the fluidized bed concept is complex, it is far from optimal and a wide range of enhancements have been developed such as United States Patent number 4,156,644, entitled "Pulsating

Sludge Bed with Inclined Plates" issued May 29, 1979, to Richard. As the complexity of the devices have grown, so too has the down time and repair costs. To attempt to simplify the situation, some devices have attempted to revert to the simpler modes of operation, or have attempted to solve the problem in unique ways. This includes United States Patent number 4,589,981, entitled

"Fluidized Bed Classifier" issued May 20, 1986, to Barari et al. and United States Patent number 4,521,303, entitled "Solids Separation in Self-Circulating Magnetically Stabilized Fluidized Bed" issued June 4, 1985, to Hicks et al. In all of these apparatuses, the mechanism becomes more and more expensive to operate and acquire. This makes them less than ideal for many situations.

Perhaps the most illustrative of the techniques currently used are the ones developed to separate tobacco leaves and parts from sand. These include: United States Patent Number 4,216,080, entitled "Method and Apparatus for Separating Sand from Botanical Fines" issued August 5, 1980, to Summers et al.5 United States Patent number Re 29,625, entitled "Process and Apparatus for Separating Sand from Botanical Materials" issued May 9, 1978, to Summers; and, United States Patent number 3,842,978 entitled

"Process and Apparatus for Separating Sand from Botanical Materials" issued October 22, 1974, to Summers.

In these inventions, the contaminated mixture (tobacco fines and sand) is dropped into a fluidized bed arrangement where it is supported by a grate. Air is drawn through the grate which causes the contaminated mixture to "bubble." The heavier sand falls through the grate . The bubbling ac tion pulls a partially cleaned mixture of sand and fines up to a cyclone separator which performs a final cleaning of the mixture.

The f inal cleaning by the cyclone separator is necessary since it is this cyclone separator which provides the air draft to

"suck" the partially cleaned mixture from the f luidized bed .

In these inventions, the use of the fluidized bed is required since the con aminated mixture must have a certain amount of dwell time within the separating mechanism. The dwell time within the bed is necessitated by the very nature of the cyclone separator which i s extremely sensitive to many factors including the f eed and exhaust tubing arrangement, physical damage to the input and exhaust ports , motor speed, variations in power source, etc. It is clear from the foregoing that except for the expensive and delicate fluidized bed arrangements, an eff icient inexpensive solution to the separation of parti cles does no t exis t.

Summary of the Invention:

The present invention deals with separating particles based upon their relative densities . For purposes of discussion herein , the separation of plastic media (i. e. ther oset or thermoplastic particles) from contaminants such as sand , paint particles, metal flakes, etc will be used. The invention is not so limited and those of ordinary skill in the art readily recognize other such applications , including but not limited to tobacco fine/sand separation, mineral (e.g. gold dust) extraction, the removal of dust/fines from usable materials and hazardous materials removal.

Additionally, within this discussion, the separation of materials in a "dry" environment using air will be used. The invention is not so limited and it is readily apparent to those of ordinary skill in the art that this invention can as readily separate liquid mixtures having different densities and may use selected gases instead of "air."

Additionally, although the present discussion refers to the use of "air," those of ordinary skill in the art readily recognize that other gases, such as helium, can be used.

In the present invention, the' ixed particles are deposited into a substantially vertical air channel, such as pipe. An air flow is established in the air channel using an air flow amplifier. This air flow is sufficient to entrain the lighter density material, but is insufficient to entrain the heavier density materials which are allowed to fall into a receptacle. The entrained lighter density material is conveyed to another receptacle or container . As example, in the case of a mixture of plastic media and contaminants, the plastic media has a much lower density than the typical contaminants of sand, metal flakes, and even paint particles. When the present invention is utilized to separate the particles, the contaminants of sand, metal flakes, and paint particles fall into a container while the plastic media conveyed into another container for future use. The separated contaminants can then be easily disposed.

One Important aspect of the present invention is its creation of the separating air flow . The invention u tilizes an air f low amplifier. Some such air flow amplifiers are well known in the art. Some examples are: United States Patent number

4,046 ,492, entitled "Ai r Flow Ampli fier" issued September 6 , 1977 , to Inglisϊ United States Patent number 4, 385,728, entitled "Flow-Ampli f ying Nozzle" issued May 31 , 1 983, to Inglis et al. ; and United States Patent number 4,195,780 , enti tled "Flow Amplifying Nozzle" issued April 1 , 1980, to Inglis (all of which are incorporated herein to by reference) . Commercially, air amplifiers of relatively high amplification ratio are available from Vortec Corporation and are ref erred to as "trans vectors". The key to an air flow amplifier is that it utilizes air pressure under high pressure. This high pressure air is directed through an air channel. As the high pressure air flows, it naturally sucks or draws the hereto for static air along.

Because the resul ting air flow is establi shed by use of a relatively small amount of hi gh pressure air, an air compressor can easily establish a source of high pressure air that is relatively constant. This assures that the air flow within the air channel does not ei ther drop the lighter density particles nor does it entrain and carry the heavier density particles.

In this regard, it has been determined that the separation of plastic media having the f ollowing sizes can be separated using a five inch trans vector from Vortec Corporation operating on a five inch pipe:

20 mesh 18 psi ;

30 mesh 16 psi;

40 mesh 14 psi .

The contaminated mixture is deposited into the air channel through the use of slots around the circumferance of the ai r channel. In the preferred embodiment of the invention, these slots permi t the contaminated mixture to fall along the walls of the air channel in a sheeting action to permit the air flow to efficiently separate the particles. The slots can be either fixed in size or may be adjus table depending upon the appli cation and the mixture of interest .

In the pref erred embodiment, to encourage the contaminated mixture to readily fall via the dropping mechanism, a vibrator is attached to the mechani sm to prevent "lodging" of the mixture and to assure a flow. Those of ordinary skill in the art readily recognize o her mechanisms which will accomplish this function. Another important aspect of the present invention is the prefered embodiment's use of a final washing apparatus. The final washing apparatus is a ring or other deflection device to f orce the f alling mixture away from the walls of the air channel and into the main flow.

In certain applications , the use of a final was hing apparatus i s extrememly benef icial. It has been found that due to the boundary layer affect, the airflow next to the air channel is much slower than that in the middle of the air channel. The slower airflow is insufficient to entrain the targetted material and as such it permits the contaminated mixture to fall unwashed. The deflection for a final wash, pushes the contaminated mixture towards the center of the air channel where the airflow will wash and entrain the ligher particles and permit the heavier particles to continue to fall.

In the preferred embodiment of the invention, the contaminated mixture is first separated into different sizes.

Each sized group or mixture is then deposited into a separator of the present invention which has been preset to remove that size plastic media from the contaminant. As noted above, the removal of plastic media having a size in the 20-30 mesh range requires an air pressure of 16-18 psi in the above described seperator. In the preferred embodiment, the separation of the contaminated mixture into sized groups is accomplished through the use of a shaker or vibrator screen assembly with varying sizes of screens. The contaminated mixture is deposited into the top screen having the largest. The partially sized material falls through a series of shaking screens which successively separate the largest to the smallest particles. These particles include both the targeted plastic media as well as the contamination. The sizing of the contaminated mixture is accomplished readily using a shaker screen such as that described by Uni ed States Patent number 3,539,008, entitled "Screening Apparatus Employing Rotating Cylindrical Screen and Stati onary Feed Means" issued November 10, 1970, to McKibben, incorporated hereinto by reference. Those of ordinary skill in the art readily recognize other such mechanisms which will operate in this envi ronment. The contami ant f rom each sized group falls through to a collection bin or container to be disposed. The cleansed plastic media is di rected , using the existing air flow, into a container for later use.

In the pref erred embodiment, the cleansed plastic media is remixed. Other applications for the cleansed particles require the maintenance of the separation of the cleansed material based upon size.

Another important aspec t of this invention is that it can size or classify materi als based no t thei r varying densities , but on the varying weights. A homongenous mi xture of a certain substance will have varying s izes of particles involved. Through the selective use of the airf low, the homogenous mixture can be separated based upon weight/size. The ai rflow entrains the smaller/lighter material and permits the heavier/larger material to fall as described before.

In this manner, a group of separator mechanisms can be used to classsif y a clean/ uncontaminated mixture wi thout the use of shaker screens or other such devices. This lat ter use of the invention is particularly useful in facilities that produce the source material and want to size or class ify it for sale.

The invention, together with various embodiments thereof will be more fully explained by the following drawings and their accompanying descriptions.

Drawings in Brief :

Figure 1 is a flow diagram illustrating the operation of an embodiment of the invention.

Figure 2 is a cut-away view of a shaker s creen assembly as used in an embodiment o f the invention.

Figure 3a and 3b are si de and top views o f an embodiment of the inventi on where three seperator tubes are utilized. Figure 4 is a perspective view of an embodiment of the invention illustrating the shaker mechanism.

Figure 5 is a cross sec tional view of the preferred embodiment of the mechanism used to deposit the contaminated mixture within the air channel for washing. Figure 6 is a cross sectional view of the preferred embodiment illustrating the f inal washing deflection mechanism.

Drawings in Detai l:

Figure 1 is a flow diagram of an embodiment of the invention. In this embodiment, the air flow amplifier 103 is supplied a high pressure source of air by compressor 104. The amplifier 103 creates an air flow within air channel 101 , 102 and 114, as illustrated by arrows 107a, 107b, 107c, and 107d.

The contaminated mixture is placed in the mixing mechanism 105 as illustrated by arrow 108. The contaminated mi ture drops 11

into air channel 101 via orfices 115. As the contaminated mixture falls within air channel 101, it separates into the lighter density particles, 110a, which are entrained by air flow 107a, and the heavier density particles, 109a, which resist air flow 107a.

The heavier or higher density particles fall as illustrated by arrows 109a and 109b into container 113 and create a pile 112 therein. If it is the heavier particles which are wanted, then this material, 112, has been cleaned and can be used for its intended application; if it is the lighter or less dense material that is desired, then the particles in container 113, will be disposed using accepted methods.

The lighter or less dense material that has been entrained into the air flow 107a, is carried upward as illustrated by arrows 110a, and 110b and 110c by air flow 107b, 107c, and 107d. Air channel 114 directs the lighter particles 110c to fall into container 106, for later use or disposal. Particles 111, within container 106, in the case of plastic media separation, are the lighter/ less dense plastic particles and have been "cleaned" for use in a plastic media blasting application.

An embodiment of the separator screen is illustrated in Figure 2. The shaker screen assembly is composed of three chambers 201, 202, and 203. The contaminated mixture is introduced into the assembly by depositing it into the top of container 201 as illustrated by arrow 213.

The entire assembly of containers 201, 202, and 203, is 12

vibrated by vibrator 204 and spring mechanisms 205a and 205b.

The un-sized material falls onto screen 207 within the container 201. Container 201 , and theref ore screen 207, is vibrated to encourage the material to pass through screen 207. Screen 207 may be of any size but in the preferred embodiment, it has a mesh size of 20.

Parti cles which are able to pass through screen 207, fall onto screen 208 within container 202. Particles which cannot pas s through screen 207 , fall through skimmer 210 and are collec ted. In the pref erred embodiment, the particles pass ing through skimmer

210 are assumed to have a size greater than 20 mesh.

A similar operati on occurs wi thin container 202 where screen 208 has a preferred mesh size of 30. Due to the vibration, particles which can pass through the screen 208 do so and f all onto tray 209. The particles which cannot pass through screen

208, fall through skimmer 211 and are collected . In the preferred embodiment of the Invention, particles passing through skimmer 21 1 have a size of be tween 20 and 30 mesh.

The particles whi ch pass through to container 203 are the smallest of the particles and are forced by tray 209 to pass through skimmer 212. These smalles t of particles are so fine that they are typically not of commercial use and are usually disposed .

The entire assembly is attached to base 206 which maintains the shaker in a fixed location during operation . Figures 3a and 3b are side and top views respectively of an embodiment of the invention where three particle sizers are used. 13

This embodiment i s particularly useful in a plastic media cleaning operation.

The contaminated media is placed wi thin drum 306. This dirty media is pushed by an air flow amplifier (not shown) up tube 307 until i t drops into the top of shaker assembly 301. Mirror

309 permits the operator to view into the top of shaker assembly 301 to make sure that the dir ty media is being supplied at the proper rate .

Shaker assembly 301 contains three screen assemblies which successively size the material with a 20 mesh s creen, 302, a 30 mesh screen , 303, and a 40 mesh screen 304. Container 305 of the shaker assembly deposits the very f ine waste material into container 308 for later disposal.

In one embodiment of this invention , the medium is fi rst processed through a cyclone seperatpr bef ore it is placed in the dirty medium drum 306. The cyclone seperator is useful for the removal of plasti c fines, paint par ticles and dust.

Each of the different screens of shaker assembly deposit the now sized, but contaminated mixture , into a dropping mechanism. As example, the particles exi ting s creen assembly 304 are deposited into dropping mechanism 310; particles from screen assembly 303 are deposi ted into dropping assembly 314.

Each of the separators operate in s imilar manner. Controls 312 supply a high pressure air flow to the air flow amplifi ers 314. Because each size group has a different weight due to the densi ties of the particles involved , the pressure supplied to each 14

air f low amplifier may be dif ferent to accommodate the varying weights. Changes in the high pressure source to the air flow amplifiers 314 also changes the air flow within the separators. As illustration, the 30-40 mesh particles that are skimmed from screen 304 are deposited into the dropping mechanism 310.

The dropping mechanism 310 permits the particles to f all into the air channel 321 via orf ices (not shown) . The air flow within air channel 321 , as created by air amplifier 314, and dic tated by controller 312, i s suff icient to entrain the lighter weight or less dense plastic medi a but is weak enough to permit the heavier contaminates to f all into container 320 f or later disposal.

The entrained plastic media is pushed upward and into bag 315. Bag 315 is used in this embodiment to remix the now clean, size separated mixture for later use. The mixed clean media is collected by container 316.

Figure 3b is a top view of the embodiment of the invention described by figure 3a.

As described earlier, the dirty media is stored in container 306 until i t is pushed into the shaker as sembly 301 through by pipe 307. Mirror 309 permits the operator to monitor the level of medium being processed by the shaker assembly 301.

Shaker assembly 301 utilizes skimmers 322a, 322b, and 322c to deposit the sized but contaminated mixtures into dropping mechanism 310, 31 1 , and 323 respectively. The cleaned and sized mixture is conveyed through pipes 317, 324, and 325, into bag 315 for remixing and subsequent deposit into clean medium container 15

316 ( not shown in this view) .

If a particular size of medium is not desired to be re-mixxed, pipe 317 can be swlveled as illustrated by arrow 318 into positi on 319 for depositing the sized, clean medium into another container . In this manner, the medium can be separated according to size if so desired.

Figure 4 is a perspective view of an embodiment of the invention. This view i llustrates the use of the shaker or separator 301. Shaker mechanism 301 has four different principal secti ons 302, 303 , 304, and 305 which contain screens for the sizing of the particle mixture deposited by pipe 307.

Each of the principal sections of shaker 301 deposits its sized particles into a separator mechanism. As example, the largest size is obtained by s creen section 302 which deposi ts its mixture into the deposi ting mechanism 311 via exit port 602. In a similar manner, exit port 601 removes the next size from shaker mechanism 303 and places the mixture into depos iting mechanism 310.

In this manner, each separator mechanism is supplied with a contaiminated mixture having a general range of size (i.e. 20-30 mesh) and is adjusted to handle that size .

Figure 5 is a cross sectional view of the preferred embodiment of the invention and illustrates the use of the slots to form a sheet of contaminated mixture entering the air channel. The contaminated mixture is dumped into the mechanism 105 as illus trated by arrow 108. The mixture collects at the bottom of the depositing mechanism 105 and falls through slots 115 into the 16

air channel 101.

Because the mixture falls through a slot, it naturally falls in a sheet as opposed to a stream. The sheet of mixture is easily separated into a lighter group of particles (which rise) and the heavier particles (which fall ) by air flow 501.

The actual width of slo ts 115 vary according to the particle sizes in question and the abi lity to feed the mixture through the slots . The narrower the slots are, the thinner the sheet of contaminated mixture wi ll be and thus the cleaning procedure will be more eff icient . The efficiency of the cleaning procedure must be balanced against the throughput desired by the mechanism .

Figure 6 illustrates an embodiment of the final wash or deflection mechanism. Through experimentation, it has been determined that due to the boundary layer affect, the airflow next to the walls of air channel 101 is less than that in the center.

Since the airflow near the wall is slower , it is incapable of entraining the lighter material and permi s it to fall with the heavier material as illustrated by arrows 601a and 601b.

To cure this, a deflection ring 116 is placed around the interior ci rcumferance of the air channel 101. The deflection ring 116 forces the falling mixture away from the wall, as illus trated by arrows 602a and 602b , and toward the center of the air channel 101 so that the appropriate air flow 107a can perform a final wash of the contaminated mixture. This final wash separates and entrains the lighter particles, illustrated by arrow

603b, while permi tting the heavier particles to continue to fall, 17

illustrated by arrow 603a.

It is clear from the foregoing that the present invention represents a new and useful device for the efficient and Inexpensive separation of particles based upon their relative weights.

Claims

18

WHAT IS CLAIMED IS: 1. A mechanism f or the separation of par ticles having a first weight from parti cles having a heavier second weight, the mechanism comprising: a) a first gas channel having a first end and a second end , said first gas channel being disposed such that the f irst end is positioned above the second end; b) a second gas channel having a f irst end and a second end; c) a gas flow amplifier attached to the first end of said first gas channel , said gas flow amplifier directing a gas flow into the second gas channel via the first end thereof ; and, d) means f or depositing a mixture of said firs t particles and said second particles into said first gas channel at a point below said gas flow amplifier .

2. The mechanism according to claim 1 further comprising means for washing any mixture falling along the walls of said first gas channel .

3. The mechanism according to claim 2 wherein said means for washing includes a deflec tion ring. 19

4. The mechanism according to claim 3 wherein said means for depositing includes means for depositing said mixture in a sheet .

5. The mechanism according to claim 4 further comprising gas compression means f or supplying a compressed gas flow to said gas flow amplifier.

6. The mechanism according to claim 5 further comprising control means for control of the gas pres sure being delivered from said gas compression means to said gas flow amplifier and wherein said control means has an operator selective means to establish an amplified gas flow which will suspend and move said f irst particles yet permits the heavier second particles to fall due to gravational forces.

7. The mechanism according to claim 6 further comprising means for sizing for es tablishing that said first par ticle and said second parti cle are approximately the same size, and wherein said means for sizing operates on said mixture prior to said mixture being deposited into said f irst gas channel. 20

8. The mechanism according to claim 7 wherein said means for s izing includes a s haker screen .

9. The mechanism according to claim 7 further comprising means for moving the mixture from said means for sizing to said means for depositing.

10. The mechanism according to claim 9 f urther comprising agitation means f or encouraging said mixture to pass through said means for depositing.

11. The mechanism according to claim 9 f urther comprising: a) a first container f or storage of said mixture; b) a second means for moving said mixture from said first container to said means for sizing; c) a second container positi oned at the second end of said first gas channel for receipt of said second particles; and , d) a third container positioned at the second end of said second gas channel for receipt of s aid first particles. 21

12. A system for the separation of lighter particles from a mixture of particles having varying sizes and having at least two weights, said system comprising: a) container means for holding said mixture of particles; b) means for sizing said mixture into N sized-mixtures where the particles within each sized-mixture have comparable sizes , and where N is an integer greater than 1 ; c) N particle separators, each particle separator operating on a selected one of said sized-mi tures and wherein each of said particle separators has:

1) a first gas channel having a first end and a second end, said first gas channel being disposed such that the first end is positioned above the second end,

2) a second gas channel having a first end and a second end,

3) a gas flow amplifier attached to the first end of said first gas channel, said gas flow amplifier directing a gas flow into the second gas channel via the first end thereof, and, 4) means for depositing the selected sized mixture into said first gas channel at a point below said gas flow amplifier. 22

13. The system according to claim 12 further comprising N means for washing, each of said means for washing located in one of said first gas channels.

14. The system according to claim 13 wherein each of said N means for washing includes a means for deflecting any mixture dropping along the wall of an air channel towards the center of the air channel.

15. The system according to claim 13 wherein said means for depositing includes means for depositing said sized-mixture in a sheet.

16. The system according to claim 15 further comprising gas compression means for supplying a compressed gas flow to each of said gas flow amplifiers.

23

17. The system according to claim 16 further comprising control means for control of the gas pressure being delivered from said gas compression means to each of said gas flow amplifiers and wherein said control means has an operator selective means to establish an amplified gas flow within each of said first gas channels which will suspend and move said first particles yet permits heavier particles to fall.

18. The system according to claim 17 wherein said means for sizing includes a shaker screen assembly having N selected mesh sizes .

19. The system according to claim 18 further comprising means for removing large particles from said mixture prior to said means for sizing.

20. The system according to claim 17 fur her comprising N means for moving the mi ture from said means for sizing to said means for depositing. 24

21. The system according to claim 20 further comprising N agitation means for encouraging said mixture to pass through the respective means for depositing.

22. A mechanism for the separation of particles having a first density from particles having a higher second density, the mechanism comprising: a) a first air channel having a first end and a second end, said first air channel being disposed such that the first end is positioned above the second end; b) a second air channel having a first -end and a second end; c) means for depositing a mixture of said first particles and said second particles into said first air channel at a point between the first end and the second end of said first air channel and thereby causing the particles within the mixture to fall toward the earth; and, d) an air flow amplifier attached to the first end of said first air channel, said air flow amplifier directing an air flow into the second air channel via the first end thereof, and creating an air flow with said first air channel sufficient to entrain said first particles therein prior to completion of the fall of said first particles.

23. The mechanism according to claim 22 further comprising means for washing any mixture falling along the walls of said first air channel .

24. The mechanism according to claim 23 wherein said means for washing includes a deflec tion ring.

25. The mechanism according to claim 23 wherein said means for depositing includes means for depositing in a sheet.

26. The mechanism according to claim 25 further comprising air compression means f or supplying a compressed air flow to said air f low amplifier.

27. The mechanism according to claim 26 further comprising control means for control of the ai r pres sure being delivered from said air compression means to said air flow amplifier and wherein said control means has an operator selective means to establish an ampli fied air flow which will suspend and move said f irst parti cles yet permits the heavier second particles to fall due to gravational forces.

28 The mechanism according to claim 27 f urther comprising means for sizing for es tablishing that said first particle and said second parti cles are approxima tely the same size , and wherein said means for sizing operates on said mixture prior said mixture being dropped into said first air channel .

29. The mechanism according to claim 28 wherein said means for s izing includes a shaker screen .

30. The mechanism according to claim 29 further comprising means for moving the mixture from s aid means for sizing to said means for depositing.

31. The mechanism according to claim 29 further comprising agitation means f or encouraging said mixture to pass through said means for depositing.

32. The mechanism according to claim 30 further comprising : a) a first container f or storage o f said mixture; b) a second means for moving said mixture from said first container to said means for sizing; c) a second container positi oned at the second end of said first air channel for receipt of said second particles; and , d) a third container positioned at the second end of said second air channel for receipt of said fi rst particles.

33. A system for the separation of higher density particles from a mixture of particles having varying sizes and having at least two densities, said system comprising: a) container means for holding said mixture of particles; b) means for sizing said mixture into N sized-mixtures where the particles within each sized-mixture have comparable sizes, and where N is an integer greater than 1; c) N particle separators, each particle separator operating on a selected one of said sized-mixtures and wherein each of said particle separators has:

1) a first air channel having a first end and a second end, said first air channel being disposed such that the first end is positioned above the second end,

2) a second air channel havi g a first end and a second end,

3) an air flow amplifier attached to the first end of said first air channel, said air flow amplifier directing an air flow into the second air channel via the first end thereof, and, 4) means for depositing the selected sized-mixture into said first air channel at a point below said air flow amplifier.

34. The system according to claim 33 further comprising N means for washing, each of said means for washing located in a first air channel of a particle separator.

35. The system according to claim 34 wherein each of said N means for washing includes a means for deflecting any mixture dropping along the wall of an air channel towards the center of the air channel.

36. The system according to claim 35 wherein said means for depositing Includes means for depositing said sized-mixture in a sheet .

37. The system according to claim 36 further comprising air compression means for supplying a compressed air flow to each of said air flow amplifiers.

38. The system according to claim 37 fur ther comprising control means for contr ol of the air pressure being delivered from said air compress ion means to each of sai d air flow amplifi ers and wherein said control means has an operator selective means to establish an amplified air flow within each of said f irst air channels which will suspend and remove particles not of the higher densi ty and will simul aneous ly permit particles of the higher densi ty to fall.

39. The system accordi g to claim 38 wherein s aid means for sizing includes a shaker screen assembly having N selected mesh sizes .

40 ) )... The system according to claim 39 further comprising means for removing large particles from said mixture prior to said means for s izing.

41. The system according to claim 38 further comprising N means for moving the mixture from s aid means for sizing to said means for depositing.

42. The system according to claim 41 further comprising N agitation means for encouraging said mixture to pass through the respective means for depositing.

43. A system for the separation of plastic media from contaminants, said system comprising: a) container means for holding a mixture of plastic media and contami ants; b) means for sizing said mixture into N sized-mixtures where the particles within each sized-mixture have comparable sizes , and where N is an integer greater than 1 '- c) N particle separators, each particle separator operating on a selected one of said sized-mix ures and wherein each of said particle separators has:

2) a second air channel having a first end and a second end,

44. The system according to claim 43 fur ther comprising N means for washing , each of said means for washing located in a first air channel of a particle separator .

45. The system according to claim 44 wherein each of said N means for washing includes a means for deflecting any mixture dropping along the wall of an air channel towards the center of the air channel.

46. The system according to claim 45 wherein said means for depositing includes means for depositing said sized mixture in a sheet .

47. The system according to claim 46 fur ther compris ing ai r compression means for supplying a compressed ai r flow to each of said air flow amplifiers.

48. The system according to claim 47 further comprising control means for control of the air pressure being delivered from said air compression means to each of said air flow amplifiers and wherein said control means has an operator selective means to establish an amplified air flow within each of said first air channels which will suspend and remove plastic media and will simultaneously permit contaminants to fall.

49. The system according to claim 48 wherein said means for sizing includes a shaker screen as embly having N selected mesh sizes .

50. The system according to claim 48 further comprising means for removing large particles from said mixture prior to said means for sizing.

51. The system according to claim 48 further comprising N means for moving the mixture from said means for sizing to said means for depositing.

52. The system according to claim 51 further comprising N agitation means for encouraging said mixture to pass through the respective means for depositing.

53. A method of separating lighter particles from a mixture containing the lighter particles and heavier particles, the method comprising the steps of: a) sizing said mixture into N groups, each of said N groups having particles of similiar size; and, b) depositing each of said N groups into a substantially verticle airflow, said air flow being sufficient to entrain the lighter particles but being insufficient to entrain heavier particles.

54. The method according to claim 53 further comprising the step of deflecting any mixture falling along the edge of said air flow towards the center of said air flow.

55. The method according to claim 54 further comprising the step of depositing said N groups in sheets.

56. A method of separating heavier parti cles f rom a mixture containing the heavier particles and lighter particles , the method comprising the steps of : a) s izing said mixture into N groups , each of said N groups having particles of similiar size; and, b) depositing each of said N groups into a substanti ally verti cle ai rflow created by a Coanda effect, said air flow being suffi cient to entrain all but the heavier parti cles.

57. The method according to claim 56 further comprising the step of def lecting any mixture falling along the edge of said air flow towards the center of said air flow.

58. The method according to claim 57 fur ther comprising the step of depositing said N groups in sheets.