JP3704082B2 - Liquid specific gravity separator - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an apparatus for separating specific gravity of waste components in a liquid by utilizing the difference in specific gravity of the components constituting the composite waste, preferably plastic waste, particularly PET bottle waste. The present invention relates to an in-liquid specific gravity separator for effectively separating broken pieces.
[0002]
[Prior art]
Among the enormous amount of plastic waste in recent years, the plastic materials are separated and used. In particular, various kinds of drinking water in plastic bottles are sold in large quantities through plastic stores, vending machines, etc., and a lot of used plastic bottles are discarded along with this. A large amount of plastic other than plastic bottles is also discarded. In Japan, the Packaging Recycling Law was enforced in 2000, and it became necessary to establish technology for recycling waste. For recycling to petroleum products, certain types of resin pieces were removed from plastic waste. It is required to be recovered and reused for plastic molding.
[0003]
As such an example, it is possible to separate and collect polyethylene terephthalate from a used PET bottle and reuse it as a raw material for the production of recycled PET bottles or fiber regeneration. Here, the PET bottle is a container formed from a resin (PET resin) mainly composed of polyethylene terephthalate (PET), in particular, a liquid container. A PET bottle is made of a PET resin. However, the member attached to and attached to the main body is often formed of a resin of a different type.
[0004]
For example, polyethylene (PE) resin, polypropylene (PP) resin, and polystyrene (PS) resin are used for packaging films such as labels attached to the surface. The cap of the container may be a resin such as PP or PS (internal screw is PET) in addition to the PET resin. The neck screw part of the main body is often made of PET. Metal caps and paper labels are also sometimes used.
[0005]
In order to reuse PET bottles, it is necessary to separate these different types of resins. In particular, labels made of different materials must be separated from the PET bottle body by some process. Conventionally, label removal from PET bottles has been performed manually. However, although separation is reliable, there is a drawback in that work efficiency is low.
[0006]
There is also a method of removing labels in the recycling process of PET bottles. For example, the specific gravity separation method is to put crushed PET bottle fragments in a water bath such as fresh water or an alkaline aqueous solution, and leave the plastic bottle as a lightweight plastic. A resin piece such as PE resin was floated on the water surface, and the PS resin piece stayed in the middle and lower part, but the PET resin piece having a large specific gravity was deposited on the bottom part to separate the resin piece. This was a method of recovering PET resin by repeating the calm separation due to this specific gravity difference.
[0007]
[Problems to be solved by the invention]
The olefin resin such as PP resin or PE resin has a specific gravity smaller than the specific gravity 1 of clear water and seems to be easily separated by water. However, the specific gravity is about 1.04 and the PS resin has a specific gravity of about 1.34, for example. The front and back PET resins have a specific gravity greater than that of fresh water, and as described above, both tend to partially overlap and settle in water. In order to complete the separation by such a calm separation method, it is necessary to repeat the separation operation intermittently, but the intermittent operation is inefficient and the PS resin piece and the PET resin piece remain unseparated. The mixed overlap layer is discarded in order to avoid the mixing of the PS resin into the recycled PET resin, and there is a disadvantage that the PET recovery efficiency is low. Since a plastic other than PET is often used for the label, if it can be separated and removed, it can greatly contribute to the recovery of high-quality PET resin. In order to separate and collect the resin for each material from such two or more types of resin molded bodies having different materials or waste materials and other aggregates containing such different resins, a heterogeneous resin separation apparatus is required.
[0008]
The present invention has been made in view of the above problems, and provides an apparatus that efficiently separates waste and other mixtures containing different kinds of resin pieces in a liquid bath using the specific gravity difference of each resin piece. To do.
[0009]
In particular, the present invention provides a specific gravity separation device that efficiently separates resin pieces for each constituent material from a plastic bottle or other resin container.
In particular, the present invention separates the PET resin constituting the PET bottle from the resin constituting the label, and particularly separates the PET resin piece and the PS resin piece into high purity, respectively, to obtain a high-quality PET resin piece. A specific gravity separation device particularly suitable for collection and reuse is provided.
[0010]
[Means for Solving the Problems]
The submerged specific gravity separator of the present invention generally has a bottomed cylindrical separation tank, an inner cylinder with a lower end inserted into the separation tank, and a downward flow in the inner cylinder that is disposed in the inner cylinder. A mixture of heavy and light materials to be separated supplied into the inner cylinder and discharged from the lower end of the inner cylinder by the screw, and upward at the bottom wall of the separation tank In the course of the upward flow of the mixed liquid, the heavy weight having a specific gravity larger than that of the liquid in the upward flow is settled or stayed and separated. The smaller and lighter weight equivalent to the specific gravity of the liquid is levitated in the upward flow or accompanied by the upward flow, and is discharged together with the liquid from the upper discharge part at the upper part of the separation tank, and the other heavy weight piece is the lower part of the peripheral wall. Drain the liquid together with the liquid from the lower discharge part, and mix the light and heavy pieces It is intended to separate.
[0011]
Specifically, the upper discharge part is preferably an overflow discharge part that discharges an overflow of a liquid containing a lightweight material at the upper edge part of the separation tank, and is a weir that overflows the upper edge part of the separation tank, Light weight floating on the liquid surface can be discharged together with the overflow, and by making it an overflow, the upward flow in the upper part of the separation tank can be made into a quiet and less turbulent flow. There is an advantage that separation of the rising of the light weight and the dwelling of the heavy weight due to the difference can be ensured.
[0012]
Furthermore, it is preferable to form a plurality of through holes in the inner cylinder at the portion where the liquid mixture is immersed so that a part of the rising liquid outside the cylinder can be returned to the cylinder. A part of the upward flow including heavy objects outside the peripheral wall of the inner cylinder can be drawn inward through the through hole by the swirling downward flow generated in the inner cylinder by the screw, and further stirred and mixed by the screw as a downward flow Release from the bottom. In the cylinder, a part of the rising liquid refluxed through the through-hole and the newly supplied mixed liquid is mixed, and the heavy and light weight pieces are unwound from the mixture and uniformly dispersed. In the upward flow in the separation tank outside the inner cylinder, there is an effect of promoting the separation of heavy and light objects.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
The light weight and heavy weight of the mixture may be in any suitable shape, such as powder, granule, or slice, having dimensions that can be dispersed in the liquid. A heavy product is granular or flakes having a specific gravity greater than that of a liquid, while a lightweight product has a specific gravity that is less than that of a liquid or slightly higher than that of a liquid and can be accompanied by an upward flow of the liquid. Or a piece is included.
[0014]
As the liquid, a liquid having a specific gravity smaller than that of a heavy object is used, and preferably a liquid having an appropriate specific gravity adjusted in consideration of the specific gravity of a heavy object and a light object. The specific gravity of the liquid is appropriately adjusted based on the specific gravity of the light and heavy materials to be separated. Usually, water, for example, tap water, clean industrial water, and other fresh water (substantially a specific gravity of 1.00). ) Is the most widely used. In addition to fresh water, an aqueous sodium hydroxide solution can be used as the liquid to enhance the cleaning effect. The specific gravity of the liquid is adjusted by adding water-soluble polymers such as casein, gelatin, and polyvinyl alcohol to water. A specific gravity in the range of 0.95 to 1.05 can be prepared by blending the water-soluble polymer. By adjusting the specific gravity of the liquid, it is possible to separate the waste materials of plastic articles that have other specific gravity combinations.
[0015]
In the method using the in-liquid specific gravity separator of the present invention, fresh water is used as a liquid to separate light waste and heavy waste, for example, waste including plastic pieces and wood pieces. The separation device of the present invention is used to separate resin pieces such as PE, PP resin, PS resin, polycarbonate (PC) resin, or PET resin from mixed plastics by making water into a liquid. The The separation apparatus of the present invention can further separate two or more kinds of resin pieces having different specific gravities from pieces of plastic bottles or other containers as concrete waste plastic pieces, for example, PET from PET bottles. It is used to separate the resin, the PS resin piece, and the PE or PP resin piece.
[0016]
In the present invention, a mixture of light and heavy materials is supplied to the separation tank. However, the mixture can be separated from the liquid and introduced alone, or mixed with the liquid. It may be added as a liquid. A supply part is arrange | positioned so that a mixture or a liquid mixture may be thrown in in an inner cylinder. However, the supply unit may be configured to feed the mixture or the mixed liquid into the separation tank outside the inner cylinder. In this case, a part of the upward flow in the separation tank is returned to the inner cylinder. . For example, it is preferable to form the through hole in the upper part of the cylindrical peripheral wall and circulate the mixed liquid from the outside of the cylinder into the cylinder.
[0017]
One embodiment of the submerged specific gravity separation apparatus of the present invention has a cylindrical separation tank having an upper edge with an open top, a closed peripheral wall and a bottom wall to receive and separate a mixed liquid, and a separation tank. An inner cylinder opened at the lower end that is disposed and immersed in the mixed liquid, a screw that is disposed in the inner cylinder and causes the mixed liquid to flow downward, a supply unit that supplies the mixed liquid into the inner cylinder, and an upper edge of the separation tank The upper discharge part which receives the overflow of the liquid mixture from the bottom, and the lower discharge part which is provided in the lower part of the separation tank and discharges the liquid mixture.
[0018]
The separation tank receives and separates a liquid mixture of a mixture containing at least two kinds of light and heavy objects having a specific gravity difference from the liquid maintained at a predetermined specific gravity supplied from the supply unit through the inner cylinder. The inner cylinder is provided inside the separation tank so as to surround the screw, and the liquid mixture from the supply section and the mixture are mixed. The A swirling downward flow is generated by the clew and discharged to the bottom wall side of the separation tank, and the discharged mixed liquid generates an upward flow along the peripheral wall. In this upward flow, the mixed liquid is separated into a heavy object that mainly stays in the outer middle portion from the lower end due to a relative specific gravity difference with respect to the liquid, and a lightweight object that is conveyed by the upward flow. Then, the upper discharge part receives the separated lightweight object together with the overflow of the liquid exceeding the upper edge of the separation tank and discharges it, and the lower discharge part is provided from the lower part of the peripheral wall of the separation tank to the intermediate part. The liquid containing is discharged.
[0019]
In this embodiment, the liquid mixture is prepared by previously mixing a light weight and a heavy weight in a liquid maintained at a predetermined specific gravity, and continuously supplied into the inner cylinder. While the mixture is well dispersed in each piece by the screw rotating in the inner cylinder, the mixed liquid is propelled toward the bottom wall of the separation tank as a swirling downward flow and reversed along the bottom wall of the separation tank. A gentle upward flow is generated from the lower edge to the outside.
[0020]
In the area outside the inner cylinder, if the light weight has a specific gravity smaller than that of the liquid, or if the specific gravity difference with the liquid is small even if the specific gravity is slightly larger, it will float or increase the fluid resistance of the upward flow. As a result, it can rise relatively rapidly following the upward flow. Since the other heavy material has a specific gravity greater than that of the liquid, it does not accompany the upward flow and stays or sinks from the bottom wall of the separation tank to the middle portion of the peripheral wall. In this way, the mixture in the supplied mixed liquid is separated into an upper lightweight region and a lower heavy region in the separation tank outside the inner cylinder, and from the upper discharge part, the separation tank A lightweight object is discharged together with the overflow from the upper edge, and a heavy object can be taken out together with the liquid from the lower discharge part.
[0021]
In another form of the present invention, similarly, the separation tank has an upper edge whose top is opened, a closed peripheral wall and a bottom wall, and a mixture is supplied from the supply unit to the inside so that the mixed liquid is mixed. The screw is placed inside the separation tank to stir the mixed solution so as to generate a swirling downward flow, and the inner cylinder is provided inside the separation tank so as to surround the screw. In the inner cylinder, a plurality of through holes are formed in the peripheral wall so that the mixed liquid outside the inner cylinder can flow into the inner cylinder. A through-hole is arrange | positioned in the position which can attract | suck a part of liquid mixture of a separation tank through a through-hole with the screw in an inner cylinder. The through hole is preferably arranged at a higher position than the position of the screw on the peripheral wall.
[0022]
In this form, an upward flow is generated in the separation tank outside the inner cylinder, and a part of the mixed liquid in the upward flow is sucked into the inner cylinder from the through hole of the inner cylinder and taken into the inner cylinder. It is discharged again from the lower end through the tube.
[0023]
In this configuration, a mixture of light and heavy materials mixed with a liquid maintained at a specific gravity can be supplied into the inner cylinder and continuously supplied into the separation tank outside the inner cylinder. You can also. When added to the separation tank outside the inner cylinder, the mixture is sucked into the inner cylinder from the through hole in the peripheral wall of the inner cylinder by the screw inside the inner cylinder, and further flows toward the bottom wall of the separation tank as a swirling downward flow. Each piece such as a resin piece in the mixture is individually well understood and propelled downward while being washed, and hits against the bottom wall of the separation tank and is reversed to generate a gentle upward flow from the lower edge of the inner cylinder to the outside.
[0024]
As described above, in the mixture charged in the separation tank outside the inner cylinder, the light and heavy objects are not separated and mixed with the liquid, but the mixed liquid passes through the through-holes in the inner cylinder peripheral wall. Then, it is mixed with the newly introduced mixed solution by the stirring force of the screw, and the mixture is again unwound by the swirling descending flow and is subjected to separation action on the individual pieces.
[0025]
In the region outside the inner cylinder, similar to the above embodiment, even if the lightweight object is slightly heavier than the specific gravity of the liquid so that it sinks in a static flow, the difference in specific gravity with respect to the liquid is small. However, the fluid resistance of the upward flow is affected, and it can rise with the upward flow. Since the heavy material has a specific gravity greater than that of the liquid, the heavy material stays from the bottom wall of the separation tank to the middle portion of the peripheral wall without being accompanied by the upward flow. In the separation tank outside the inner cylinder, it is separated into an upper light weight area and a lower heavy weight area, and the upper discharge section discharges a lightweight object together with the overflow, and the lower discharge section removes a heavy object. Can be taken out with the liquid.
[0026]
The heavy items discharged from the lower discharge part of the separation tank and the light items discharged from the upper discharge part are separately separated from the liquid by a separating means such as an appropriate filter or sieve, dehydrated, and lightweight. The product and the heavy product are obtained separately.
[0027]
The apparatus of the present invention is preferably applicable to the specific gravity separation of plastic waste. For example, when separating a plastic bottle, the specific gravity of 1 is obtained by using water as a liquid from a plastic bottle fragment crushed by a crusher. Thus, heavy plastic pieces such as PS resin pieces and PET resin pieces can be easily separated from olefin-based lightweight plastic pieces such as PP resin and PE resin having a specific gravity of 1 or less. The separation of the PS resin piece and the PET resin piece, which are slightly larger than the specific gravity 1 and approximate the specific gravity, can be performed continuously and effectively.
[0028]
The device according to the invention has the advantage that the mixture can be washed by stirring with a screw together with a separating action. The washed-off metal, sand particles, etc. settle on the bottom wall of the separation tank and are separated.
[0029]
It is preferable that the upper discharge part is formed by arranging a soot that discharges in response to overflow beyond the upper edge of the separation tank, around the upper edge of the separation tank. The soot may be provided on a part or the entire periphery of the upper edge of the separation tank that can overflow. The upper discharge part may include a cover that covers the upper edge of the separation tank, and such a cover can prevent foreign matter from entering the separation tank from above.
[0030]
On the other hand, the upper edge of the inner cylinder may be set at substantially the same height as the upper edge of the separation tank that can overflow, so that the upper liquid in the separation tank may overflow into the inner cylinder. In this case, the partition wall is disposed between the inner cylinder and the separation tank so that the lower edge of the partition wall is positioned below the upper edge of either the inner cylinder or the separation tank. Is preferred.
[0031]
As for this partition wall, the inner wall is close to the inner cylinder in the separation tank outside the inner cylinder. By partitioning from the liquid on the discharge side, only the upward flow close to the inner cylinder is returned from the upper edge of the inner cylinder into the inner cylinder, and the heavy piece is collected. In the inner cylinder, the heavy object piece is separated from the light object piece in the swirling downward flow by the screw, and discharged again into the separation tank. The partition wall can further prevent the upper surface of the liquid on the upper discharge part side or the light-weight object pieces in the liquid from mixing into the inner cylinder, and in particular, the light-weight object that is separated and floats on the liquid surface is contained in the inner cylinder. Can be prevented, and the separation accuracy of lightweight objects can be increased.
[0032]
The upper end of the inner cylinder can be set higher than the upper edge of the separation tank to prevent overflow into the inner cylinder. The partition wall can be omitted when there is little heavy load accompanying the upward flow in the separation tank.
[0033]
Although the bottom wall of the separation tank may be flat, it is preferably formed in a tapered shape or an inverted conical shape with the central portion narrowed downward. The bottom wall can be formed with a deposited portion such as earth and sand grains or metal pieces having a specific gravity larger than that of the mixture at the center, and a drain pipe provided with an on-off valve can be connected to the deposited portion. Heavy foreign matters such as earth and sand and metal pieces washed away from the mixture by stirring with a screw can be accumulated on the bottom wall of the separation tank, and can be discharged by opening the on-off valve at appropriate times.
[0034]
Furthermore, making the bottom wall of the separation tank tapered or inverted conical increases the downward flow of the mixed liquid from the inner cylinder along the bottom wall of the separation tank and converts it into a gentle upward flow along the separation tank wall surface. can do.
[0035]
The screw preferably has a rotation shaft connected to a variable speed motor installed on the separation tank so that the rotation speed can be adjusted. Without changing the screw, by simply changing the rotation speed of the variable speed motor, the swirl downward flow suitable for the specific gravity of the liquid used and the mixture type / composition of the mixture amount is set.
The flow rate of the upward flow can be changed and adjusted.
[0036]
【Example】
Example 1.
This example shows a specific gravity separator that separates waste plastic fragments into waste plastic pieces using waste plastic fragments as a mixture and water as a liquid.
[0037]
As shown in FIG. 1, the submerged specific gravity separation device 1 is provided with a separation tank 10 having an upper edge 11 having an open top, a peripheral wall 12, and a closed inverted weight-shaped bottom wall 13. A cylindrical inner cylinder 30 is disposed, and a downflow screw 20 is disposed in the inner cylinder 30.
[0038]
The separation tank 10 is a container that receives the mixed liquid as a whole, but has a cylindrical shape, and the upper part of the separation tank 10 is covered with a cover 40. The bottom wall 13 of the separation tank 10 is formed in an inverted conical shape with the central portion positioned below, and the central portion of the bottom wall 13 is provided with a drain pipe 62 as a discharge pipe, and has a specific gravity such as earth and sand or metal. A deposit 48 is provided for receiving large deposits.
[0039]
The separation tank 10 is provided with an upper discharge part 41, and the upper discharge part 41 is composed of an annular bowl 50 arranged around the outer periphery of the upper edge 11 of the separation tank 10. It receives water overflowing from the upper edge 11 and a lightweight material, and an upper discharge pipe 51 is connected to the trough 50. The outer wall of the flange 50 is connected to the cover 40.
[0040]
The separation tank is provided with a lower discharge part 42, and the lower discharge part 42 is connected to a lower discharge pipe 61 by providing a discharge port at a lower part of the peripheral wall 12 of the separation tank 10.
[0041]
The inner cylinder 30 has a cylindrical shape with a lower end opening, is suspended and fixed from the cover 40, and the lower end 33 is arranged to extend downward from the lower surface of the cover 40 so as to be spaced from the separation tank bottom wall 13. ing. In this embodiment, the inner cylinder 30 is provided with a large number of through holes 32 in the peripheral wall. The through hole 32 is arranged from the upper part of the peripheral wall 31 to the intermediate part.
The mixed liquid supply unit 45 is arranged in the upper part of the inner cylinder 30, and a supply pipe 46 for charging the mixed liquid S into the inner cylinder is fixed through the cover 40.
[0042]
The screw 20 is disposed in the inner cylinder 30, and the blade 22 is fixed to the rotation shaft 21. The rotation shaft of the screw is connected to a variable speed motor 25 installed at the center of the upper surface of the cover 40 and is driven to rotate. The In this example, the blades 22 and 22 are attached to the rotary shaft 21 in two upper and lower stages, and a downward flow is generated in the inner cylinder by the rotation of the blades. The rotational speed of the rotary blade is adjusted by the variable speed motor 25.
[0043]
When using the separator of this embodiment, a mixture of a mixture of a heavy plastic piece (indicated by x in the figure) and a lightweight plastic (indicated by ○ in the figure) and an alkaline aqueous solution as a liquid. S is supplied into the inner cylinder 30 through the supply pipe 56. In the steady state, the mixed solution is supplied so that the state where the liquid overflows to the upper edge 11 of the separation tank 10 can be maintained.
The liquid mixture S supplied from the supply pipe 46 of the supply unit into the inner cylinder 30 forms a downward flow that descends in the inner cylinder 30 by the screw 20 of the inner cylinder. The plastic mixture supplied in the cylinder is flowed downward in water while the plastic pieces of the mixture are unwound, wetted in water, and uniformly dispersed in water.
[0044]
The downward flow in the cylinder 30 passes through the lower end portion 33 and is converted upward along the bottom wall 13 and further rises between the inner cylinder 30 and the separation tank peripheral wall 12 as indicated by a broken line in the figure. To do. Since the heavy plastic piece in the upward flow has a specific gravity greater than that of the aqueous solution, it stays in the lower part of the peripheral wall of the separation tank, and the other lightweight plastic piece has the same or smaller specific gravity than the aqueous solution. It reaches. The lightweight plastic piece LP accompanying the upward flow overflows to the upper edge 11 of the separation tank 10 together with the aqueous solution, travels along the basket 50, and is discharged by the upper discharge pipe 51. The other heavy plastic piece HP is discharged from a lower discharge pipe 61 that penetrates the lower portion of the peripheral wall 12 of the separation tank 10.
[0045]
The through-hole 32 provided in the peripheral wall of the inner cylinder 30 is arranged from a position slightly away from the upper edge 11 of the separation tank 10 to an intermediate position avoiding the retention area of the heavy plastic piece HP, and the screw 20 is The heavy plastic piece HP is sucked into the inner cylinder 30 through these through holes 32 together with the rising lightweight plastic piece LP.
[0046]
The screw 20 sucks a part of the mixed liquid outside the inner cylinder into the inner cylinder 30 through the through-hole 32 of the inner cylinder 30, and agitates and mixes with the supplied mixed liquid in the inner cylinder. Dissolve the lightweight plastic piece and let it flow out as a downward flow. In this way, the through hole 32 of the inner cylinder 30 circulates a part of the upward flow between the inside of the inner cylinder and the outside of the inner cylinder, and collects the heavy plastic piece contained in the upward flow outside the cylinder 30. Thus, the separation accuracy is improved.
[0047]
Furthermore, the screw 20 has a function of cleaning the mixture incidentally. Since the agitation action is performed on the mixed solution S containing the caustic soda aqueous solution, the plastic pieces LP and HP have a cleaning effect. The washed-out dirt having a large specific gravity is deposited in the depositing portion 48.
[0048]
In order to separate the plastic pieces LP and HP having a large specific gravity difference, it is preferable to increase the distance between the upper discharge portion 41 and the lower discharge portion 42, and the inner cylinder peripheral wall when the settling distance of the heavy plastic piece HP is sufficiently large The 31 through holes 32 can be omitted.
[0049]
As described above, the bottom wall 13 is formed in an inverted conical shape with the center portion lowered, so that the lightweight plastic piece LP given the thrust by the screw 20 has a relatively strong bottom as shown by the broken line. It strikes against the wall 13 and is reflected inward on the outer side of the inner cylinder to be transported away from the lower discharge part 42, preventing outflow from the lower discharge part 42, and again outward on the outer side of the lower part of the inner cylinder peripheral wall 31. The light is reflected and concentrated toward the upper discharge portion 41, and the separation accuracy of the lightweight plastic piece LP is improved.
[0050]
When the bottom wall 13 is flat, the lightweight plastic piece LP hits the lower end portion of the peripheral wall 12 and is reflected inwardly to be separated from the lower discharge portion 42 and transported along substantially the same path. The number of the lower discharge portions 42 is increased or decreased according to the supply amount and separation ability of the mixed solution S, but a capture plate 42a for the heavy plastic piece HP can be provided above the opening.
[0051]
The submerged specific gravity separation device 1 of this embodiment can be widely applied to combinations of resin pieces having a large specific gravity difference such that a lightweight plastic piece has a smaller specific gravity than water but a heavy plastic piece has a larger specific gravity than water. For example, a lightweight plastic piece such as olefinic PP resin or PE resin (specific gravity is about 0.93 to 0.95) and a heavy material such as PS resin or PET resin (specific gravity is about 1.04 to 1.34) Can be used for separation.
[0052]
For such a mixture, a cut piece of a used plastic bottle of a recycling object can be used. To illustrate the method of adjusting the mixture, first, the PET bottle balers collected from the market are put into a crusher after removing foreign substances such as stones, wood, metal, and color bottles, and have a size of about 50 mm. Crushing into coarse pieces, and then separating the peeled pieces of the label attached to the bottle with an air sorter or the like from the coarse pieces. It supplies to a drum magnetic separator and an aluminum separator, and a magnetic metal piece such as a cap and an aluminum cap piece are separated from each other. Thereafter, the coarsely crushed pieces are once collected in a cyclone by a transport fan or the like, and supplied to a pulverizer to make fine resin pieces of about 10 mm or less. The resin pieces include olefinic PE and PP resin fragments and PS resin and PET resin fragments.
[0053]
Next, the mixed liquid S supplied to the submerged specific gravity separator 1 is adjusted. This method is not shown, but the crushed pieces from the pulverizer are aerodynamically connected to the cyclone by a crushed piece transport fan or the like. It is transported and collected once in the cyclone. The crushed pieces in the cyclone are supplied to the fixed amount feeder through the rotary seal valve, and supplied to the liquid mixing tank for mixing with the liquid through the rotary seal valve.
[0054]
The liquid mixing tank is supplied with fresh water, caustic soda, and recovered liquid to obtain a liquid adjusted to have a caustic soda concentration of 1.5 to 3.0% by weight, and from the pH adjusting tank. It is comprised from the stirring tank which mixes a liquid and a grinding | pulverization piece. Appropriately mixed liquid of polyethylene terephthalate (PET) and polystyrene (PS) of lightweight plastic pieces HP and polyethylene plastic terephthalate (PET) and heavy weight plastic pieces HP, which are crushed pieces of transparent plastic bottles, in a stirring tank A liquid mixture S having a good fluidity is produced.
[0055]
Example 2
The in-liquid specific gravity separator 1 of this embodiment is a combination of plastic pieces having a specific gravity approximate to include a resin piece having a small specific gravity difference with water, for example, a PS resin piece (specific gravity is about 1.04) and PET (specific gravity). Is effective for separation of about 1.34). The submerged specific gravity separator of this example is a heavy plastic piece HP separated from the heavy plastic piece HP separated by the submerged specific gravity separator 1 implemented in the first embodiment, and further a PET resin piece and a lightweight one as a heavy article from the heavy plastic piece HP. Can be used to separate PS resin pieces.
[0056]
This submerged specific gravity separator 1 is shown in FIG. 2 and has the same basic structure as the submerged specific gravity separator 1 of Example 1, but uses a partition wall 38 at the upper edge of the separation tank and the inner cylinder. The point I made is different.
[0057]
The inner cylinder 30 has an upper edge 36 that is substantially the same height as the upper edge 11 of the separation tank 10 (i.e., the liquid in the separation tank is also on the upper edge 11 side of the separation tank at the same time. It is adjusted so that it can overflow to the side of 36 and is supported by the bracket 37 from the peripheral wall 12 of the separation tank 10. In this embodiment, the partition wall 38 has a cylindrical shape that can be inserted between the inner cylinder 30 and the separation tank 10, is fixed to the lower surface of the cover 40 and is suspended, and the lower edge 39 of the partition wall 38 is Between the upper edge part of the separation tank 10 and the upper edge part of the inner cylinder 30, it is located so that it may be located below both upper edges 11,36.
[0058]
The ascending flow between the inner cylinder and the separation tank is an area near the separation tank peripheral wall (outward basin) that is mostly made up of lightweight materials. The basin) is a distinction between ascending flows mixed with light and heavy objects. In the partition wall 38 of this embodiment, a slight amount of heavy plastic piece (PET resin piece) is light in the upward flow including almost pure light plastic piece (for example, PS resin piece) in the outer flow area outside the insertion portion. It partitions from the upward flow mixed with the PS resin piece of the object. As a result, the high-purity lightweight PS resin piece in the outer basin is discharged and separated from the upper discharge part 41, and the upward flow is obtained by mixing the PET resin piece with the PS resin piece in the inner basin. Overflowing to the inside of the inner cylinder 30 and taking it in again, the dispersion can be increased and the separation accuracy can be increased. The separation accuracy can also be adjusted by adjusting the insertion depth of the partition wall 38 insertion portion.
[0059]
In the above-described two embodiments, the example in which the supply portion 45 of the mixed liquid S is disposed inside the inner cylinder 30 has been described. However, since the through hole 32 is provided in the inner cylinder 30, the supply portion Outside, the peripheral wall 12 of the separation tank 10 may be arranged close to the opening of the through hole 32 so as not to interfere with the upward flow.
In addition, in order to ensure an appropriate overflow in the upper discharge part and a discharge liquid flow in the lower discharge part, a liquid of the same quality is separately supplied in the inner cylinder or in the inner part to ensure the flow rate separately from the mixed liquid. Supplying to the separation tank outside a cylinder is made suitably.
[0060]
【The invention's effect】
The apparatus of the present invention creates a quiet upward flow along the peripheral wall of the separation tank by using a screw rotating in an inner cylinder of a mixed liquid in which a light weight and a heavy weight are mixed with a liquid maintained at a predetermined specific gravity. Light items are separated from the upper discharge part provided at the upper edge of the separation tank, and heavy items are separated from the lower discharge part provided at the peripheral wall of the separation tank together with the liquid. And it can sort continuously.
[0061]
In the present invention, if the upper discharge section is an overflow discharge section that discharges an overflow of liquid containing a lightweight material at the upper edge of the separation tank, the separated lightweight object is floated on the water surface to overflow the liquid. The flow can be easily and efficiently collected.
[0062]
In particular, ascending flow that rises along the peripheral wall of the separation tank is used, so even a strip having a specific gravity slightly larger than that of the liquid can be raised along with the ascending flow. It can be recovered. On the other hand, it can be effectively separated from a heavy object having a relatively higher specific gravity than the liquid. As described above, even particles and crushed pieces having specific gravity close to each other can be efficiently separated by appropriately selecting the specific gravity of the liquid.
[0063]
Since the present invention is provided with the lower discharge part for discharging the liquid containing heavy objects provided on the lower peripheral wall of the separation tank, the heavy objects staying in the liquid of the separation tank can be recovered together with the liquid. There is an advantage that it can be effectively separated from a substance having a specific gravity large enough to precipitate in the liquid.
[0064]
If many through-holes are opened in the inner cylinder, even if both light and heavy objects are mixed in the upward flow outside the inner cylinder in the separation tank, it will be repeated from the through-hole in the inner cylinder peripheral wall into the inner cylinder. Since it can be sucked, it is transported to the separation tank by the swirling downward flow together with the newly introduced mixed liquid and gives a separation action in the upward flow, so that the separation efficiency can be improved.
[0065]
If water or an aqueous solution is used as the liquid, the apparatus of the present invention is made of a heavy plastic piece such as a PS resin piece or a PET resin piece having a specific gravity greater than that of water, and a plastic such as a PP resin piece or a PE resin piece having a specific gravity smaller than that of water. Separation from the pieces is very easy. Furthermore, there is an advantage that it is possible to easily and effectively separate a PS resin piece having a specific gravity larger than water but having an approximate specific gravity from a PET resin piece having a higher specific gravity.
[0066]
If the inner cylinder is provided with a through-hole in the peripheral wall above the screw in the inner cylinder, the heavy object entangled with the lightweight object during the upward flow can be sucked into the inner cylinder again through the through-hole, and again Dispersed and discharged in the inner cylinder, the separation workability in the upward flow is improved, and the separation accuracy can be increased. If the through hole is provided in the upper part of the peripheral wall, it is possible to prevent the heavy object that has been separated and staying outside the inner cylinder by the swirling downward flow in the inner cylinder by the screw from being taken into the inner cylinder again.
[0067]
The inner cylinder has a partition wall whose upper edge is set at the same height as the upper edge of the separation tank, and the inner cylinder is located between the inner cylinder and the separation tank so that its lower edge is positioned below the upper edges of both. If arranged, the inwardly mixed liquid in which the accompanying heavy material is relatively likely to be mixed in the upward flow can be collected in the inner cylinder and dispersed again in the inner cylinder to be subjected to a separation operation. Moreover, a partition wall can partition the liquid flow by the side of a separation tank surrounding wall, can prevent mixing to the upper discharge part side of a heavy article, and can improve the separation precision of a lightweight article.
[0068]
If the bottom wall of the separation tank is formed in an inverted conical shape at the center, it can be used as a deposit for foreign matter having a large specific gravity, and the deposit can be appropriately discharged from a drain pipe provided with an on-off valve. The reverse conical separation tank bottom wall is designed to have an appropriate taper angle so that the swirling downward flow from the inner cylinder lower end can be converted into a gentle upward flow along the separation tank peripheral wall. It is effective for separation of particles and fragments with similar specific gravity.
[Brief description of the drawings]
FIG. 1 is a schematic longitudinal sectional view of a submerged specific gravity separator according to an embodiment of the present invention.
FIG. 2 is a schematic longitudinal sectional view of a submerged specific gravity separator according to another embodiment of the present invention.
[Explanation of symbols]
1 Liquid specific gravity separator
10 Separation tank
11 Upper edge
12 wall
13 Bottom wall
20 screw
30 inner cylinder
32 Through hole
38 partition wall
41 Upper discharge part
42 Lower discharge part
45 Supply section
HP heavy plastic pieces
LP Lightweight plastic piece
S mixture

Claims (12)

Mixture and, and light product and heavy mixture by utilizing the difference in specific gravity in a mixture of a liquid having a specific gravity lower than the specific gravity of the weight of the lightweight material and heavy to be of different separation specific gravity made of resin piece In the liquid specific gravity separator for separating into
The liquid specific gravity separator is
A bottomed vertical separation tank for receiving the mixed liquid and separating it into a lightweight and heavy article;
A vertical inner cylinder with an open lower end disposed in the separation tank and spaced from the bottom wall;
A supply unit arranged at the upper part in the inner cylinder, and charging the mixture into the inner cylinder;
A screw for placing in the inner cylinder, stirring the mixed liquid to form a swirling downward flow, and generating an upward flow in the separation tank outside the inner cylinder;
An upper discharge part that is provided in the upper part of the separation tank and discharges the liquid together with the lightweight object;
A submerged specific gravity separator comprising a lower discharge portion provided at a lower portion of the peripheral wall of the separation tank and configured to discharge a heavy object staying in the liquid together with the liquid.   The apparatus according to claim 1, wherein the upper discharge portion is configured to dispose a soot that receives and discharges the overflow beyond the upper edge of the separation tank around the upper edge of the separation tank. The apparatus according to claim 1 or 2 , wherein a plurality of through holes are formed in the inner cylinder so that a part of the mixed liquid outside the inner cylinder flows back into the inner cylinder at a mixed liquid immersion portion of the peripheral wall. The plurality of through holes, according to claim 3 which is disposed in a position that allows sucking part of the mixture outside the inner cylinder through the through-hole by a screw in the inner cylinder.   The apparatus according to any one of claims 1 to 4, wherein the supply unit is arranged to supply into a separation tank outside the inner cylinder instead of inside the inner cylinder.   The upper edge of the inner cylinder is set at substantially the same height as the upper edge of the separation tank, and a partition wall having a lower edge located below any of the upper edges is disposed between the inner cylinder and the separation tank. The apparatus according to any one of claims 1 to 5, wherein a part of the liquid mixture in the separation tank can overflow into the inner cylinder beyond the upper edge of the inner cylinder.   The apparatus according to any one of claims 1 to 5, wherein an upper edge of the inner cylinder is set at a position higher than an upper edge of the separation tank.   The apparatus according to any one of claims 1 to 7, wherein the liquid is water or an aqueous solution, the heavy article is a PET resin piece, and the light article is a resin piece having a specific gravity smaller than that of the PET resin piece.   The apparatus according to claim 8, wherein the lightweight object includes a PS resin piece.   The apparatus according to any one of claims 1 to 9, wherein the mixture includes a fragment of PET bottle waste. The bottom wall of the separation tank is formed in an inverted conical shape with the central portion lowered to form a deposit portion of foreign matter having a specific gravity larger than that of the mixture, and a discharge pipe having an on-off valve is connected to the deposit portion. Or the apparatus according to any one of 10.   The apparatus according to any one of claims 1 to 11, wherein a rotating shaft of the screw is suspended from the separation tank and is rotationally driven by a variable speed motor.

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