JP2008213220A - Gravity concentration device for waste resin flake - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a gravity concentration device for waste resin flake efficiently separating mixture of waste resin flake having fine specific gravity difference in a short period of time. <P>SOLUTION: A mixture of PE flake and PP flake quietly conveyed in an intermediate layer part of a specific gravity liquid in a specific gravity liquid tank 4C by a screw conveyer 4D starts sedimentation from the intermediate layer part of the specific gravity liquid of an approximately static state of the PE flake having the specific gravity of 0.96, and starts surfacing from the intermediate layer part of the specific gravity liquid of an approximately static state of the PP flake having the specific gravity of 0.91, and thus the mixture of PE flake and PP flake having a fine specific gravity difference is efficiently separated in a short period of time. The PE flake precipitates to the lower layer part of the specific gravity liquid is received by a pipe conveyor 4E and conveyed from the bottom part of the specific gravity liquid tank 4C, and the PP flake surfacing to the upper layer part of the specific gravity liquid is scraped out by a conveyer 4F with a rake and conveyed from the upper part of the specific gravity liquid tank 4C. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a specific gravity sorting apparatus for waste resin flakes that sorts a mixture of waste resin flakes with a specific gravity liquid.

  In order to recycle waste resin such as various synthetic resin bottles collected separately for each raw material resin, the waste resin flakes are crushed into flakes using a crusher and the mixture of waste resin flakes is submerged in water. Alternatively, a method and apparatus for selecting specific gravity for each raw material resin in a specific gravity liquid are generally known.

  As a specific gravity sorter of this kind, Patent Document 1 discloses that waste synthetic resin crushing flakes (waste resin flakes) are introduced from above into a specific gravity liquid in a separation tank (specific gravity liquid tank) to generate convection in the specific gravity liquid. An apparatus is disclosed that disperses crushed flakes and sorts them into crushed flakes having a low specific gravity and crushed flakes having a large specific gravity that settle.

Further, in Patent Document 2, a mixture of crushed plastic (waste resin flakes) is supplied to the center of the specific gravity liquid while swirling in the radial direction of a cylindrical tank (specific gravity liquid tank) whose upper and lower sides are conical. An apparatus that separates specific gravity into crushed plastic having a small specific gravity and crushed plastic having a large specific gravity by an upward flow and a downward flow generated from the center of the specific gravity liquid is disclosed.
JP 2001-162191 A (abstract) JP-A-9-150417 (abstract)

  By the way, in the specific gravity sorter described in Patent Document 1, convection occurs in the specific gravity liquid in the specific gravity liquid tank, and in the specific gravity sorter described in Patent Document 2, swirling to the specific gravity liquid in the specific gravity liquid tank. Flow, upflow, downflow, etc. are generated. For this reason, when there is a large specific gravity difference in the mixture of waste resin flakes such as crushed flakes and crushed plastics, they can be accurately selected by specific gravity. For example, like a mixture of waste polypropylene flakes and waste polyethylene flakes. However, when the specific gravity difference is very small, it is not possible to efficiently select these in a short time.

  Accordingly, an object of the present invention is to provide a specific gravity sorting apparatus for waste resin flakes capable of efficiently sorting specific gravity of a mixture of waste resin flakes having a small specific gravity difference in a short time.

  A specific gravity sorting device for waste resin flakes according to the present invention is a specific gravity sorting device for waste resin flakes that sorts a mixture of waste resin flakes with a specific gravity liquid in a specific gravity liquid tank, wherein the mixture of waste resin flakes is the specific gravity liquid. A screw conveyor that can be carried into the middle layer of the specific gravity liquid in the tank, a pipe conveyor that can receive waste resin flakes having a large specific gravity that has settled in the lower layer of the specific gravity liquid, and can be carried out from the bottom of the specific gravity liquid tank, and the specific gravity It is characterized by comprising a conveyor with a rake capable of scraping out the waste resin flakes having a small specific gravity floating on the upper layer portion of the liquid and carrying it out from the upper part of the specific gravity liquid tank.

  In the specific gravity sorting device for waste resin flakes according to the present invention, when the mixture of waste resin flakes is carried into the middle layer of the specific gravity liquid in the specific gravity tank by the screw conveyor, the waste resin flakes having a large specific gravity are in a substantially stationary specific gravity. Sedimentation starts from the middle layer of the liquid, and the waste resin flakes having a small specific gravity start to float from the middle layer of the specific gravity liquid in a substantially stationary state. For this reason, a mixture of waste resin flakes having a small specific gravity difference, for example, a mixture of waste polyethylene flakes having a specific gravity of 0.96 and waste polypropylene flakes having a specific gravity of 0.91 is also efficiently separated in a short time.

  The waste resin flakes with high specific gravity settled in the lower layer of the specific gravity liquid (waste polyethylene flakes) are gently received by the pipe conveyor and carried out from the bottom of the specific gravity liquid tank while keeping the specific gravity liquid substantially stationary. The waste resin flakes with low specific gravity (waste polypropylene flakes) floating on the upper layer of the liquid are gently scraped out by the conveyor with rake and carried out from the upper part of the specific gravity liquid tank.

  In the specific gravity sorting apparatus for waste resin flakes of this invention, the pipe conveyor has a plurality of blades arranged in a drive chain circulating in the pipe casing, and the specific gravity liquid is gently permeated through the blades, and the specific gravity liquid tank A transmission hole is formed in order to keep the inside substantially stationary. Further, the conveyor with a rake is configured to scrape the waste resin flakes having a small specific gravity floating above the specific gravity liquid upward along an inclined receiving plate installed in the upper part of the specific gravity liquid tank. Since the specific gravity liquid adhering to the waste resin flakes flows down along the inclined receiving plate and is collected in the specific gravity liquid tank, it is preferable.

  Further, in the specific gravity sorting apparatus for waste resin flakes of the present invention, a specific gravity liquid spare tank configured to circulate the specific gravity liquid in the specific gravity liquid tank, and a specific gravity for measuring the specific gravity of the specific gravity liquid in the specific gravity liquid spare tank It is preferable that a meter is attached because the specific gravity of the specific gravity liquid in the specific gravity tank can be accurately managed.

  In the specific gravity sorting apparatus for waste resin flakes according to the present invention, waste resin flakes having a large specific gravity start to settle from the middle part of the specific gravity liquid in a substantially stationary state, and waste resin flakes having a low specific gravity are the middle layer of a specific gravity liquid in a substantially stationary state As a result, the mixture of waste resin flakes having a small specific gravity difference is efficiently separated in a short time. Then, the waste resin flakes having a large specific gravity that settled in the lower part of the specific gravity liquid are received by the pipe conveyor while keeping the specific gravity liquid in a substantially stationary state, and are carried out from the bottom of the specific gravity liquid tank, and floated on the upper layer part of the specific gravity liquid. Waste resin flakes with a small specific gravity are scraped out by a conveyor with a rake and carried out from the upper part of the specific gravity liquid tank.

  Therefore, according to the specific gravity sorting apparatus for waste resin flakes according to the present invention, it is possible to efficiently sort the mixture of waste resin flakes having a small specific gravity difference in a short time.

  BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a preferred embodiment of a specific gravity sorting apparatus for waste resin flakes according to the present invention will be described with reference to the accompanying drawings. Here, FIG. 1 of the attached drawings is a schematic view showing a waste resin flake sorting line equipped with a specific gravity sorting device for waste resin flakes according to one embodiment, and FIG. 2 is an arrangement relation of the waste resin flake sorting line shown in FIG. FIG.

  The waste resin flake sorting line shown in FIG. 1 is a mixture of various types of waste resin flakes, such as waste polyethylene flakes (hereinafter abbreviated as PE flakes), waste polypropylene flakes (hereinafter abbreviated as PP flakes), waste polyethylene terephthalate flakes (hereinafter referred to as “frequent polyethylene flakes”). This is a line for selecting and collecting PE flakes and PP flakes from a mixture of waste polystyrene flakes (hereinafter abbreviated as PS flakes).

  This waste resin flake sorting line includes a raw material supply device 1, a water sorting device 2, a dehydrating device 3, a specific gravity sorting device 4, a dehydrating device 5, a recovery weighing device 6, and a dehydrating device arranged as shown in the plan view of FIG. 7. A recovery weighing device 8 is provided.

  As shown in FIG. 1 and FIG. 3, the raw material supply apparatus 1 includes raw materials (PE flakes, PP flakes, PET flakes, PSs) fed into a hopper type raw material tank 1C from a flexible container 1B suspended from a hoist crane 1A. The mixture of flakes) is fed into the cyclone 2A of the water sorting apparatus 2 through the conveying screw 1D and the blower 1E.

  As shown in FIGS. 1 and 4, the water sorting device 2 includes a cyclone 2A that removes air from the raw material blown by the blower 1E of the raw material supply device 1, and PE cyclones, PP flakes, PET flakes from the cyclone 2A, A hopper-type stock tank 2B into which a mixture of PS flakes is charged, and a mixture of PE flakes, PP flakes, PET flakes, and PS flakes from the stock tank 2B in the middle layer of the sorted water in the water sorting tank 2C, And it has screw conveyor 2D carried in to a center part.

  Here, the water sorting tank 2C sorts PET flakes and PS flakes having a higher specific gravity than the selected water, and PE flakes and PP flakes having a lower specific gravity than the selected water, at the bottom of the water sorting tank 2C. Is provided with a screw conveyor 2E that collects PET flakes and PS flakes settled in the lower layer of the sorted water as foreign matter.

  A paddle conveyor 2F is attached to the upper part of the water sorting tank 2C to scrape the PE flakes and PP flakes floating on the upper layer of the sorted water with the paddle 2F1 and carry them to the dehydrator 3 side.

  The dewatering device 3 receives the PE flakes and PP flakes containing the sorted water scraped out by the paddle conveyor 2F through the inclined duct 3A. The dewatering device 3 dewaters the selected water adhering to the PE flakes and PP flakes by centrifugal action, and supplies the mixture of the dehydrated PE flakes and PP flakes into the cyclone 4A of the specific gravity sorting device 4 by the blower 3B. .

  As shown in FIG. 1, FIG. 5 and FIG. 6, the specific gravity sorting device 4 includes a cyclone 4A for excluding air from a mixture of PE flakes and PP flakes blown by the blower 3B of the dewatering device 3, and the cyclone 4A to PE. A hopper-type stock tank 4B into which a mixture of flakes and PP flakes is charged, and a mixture of PE flakes and PP flakes from the stock tank 4B is brought into the middle part of the specific gravity liquid in the specific gravity liquid tank 4C Screw conveyor 4D.

  Here, the specific gravity liquid tank 4C is for efficiently sorting the specific gravity of a mixture of PE flakes having a specific gravity of 0.96 and PP flakes having a specific gravity of 0.91 with a specific gravity liquid in a short time. The specific gravity is adjusted to about 0.935 by mixing isopropyl alcohol (IPA) and water.

  And the pipe conveyor 4E which collect | recovers PE flakes with a specific gravity of 0.96 which settled in the lower layer part of the specific gravity liquid, and carries it out to the dehydrator 5 side is attached to the bottom part of this specific gravity liquid tank 4C. In addition, a rake-equipped conveyor 4F that scrapes PP flakes having a specific gravity of 0.91 floating on the upper layer of the specific gravity liquid with the rake 4F1 and carries them to the dehydrator 7 side is attached to the upper part of the specific gravity liquid tank 4C.

  The screw conveyor 4D is operated at a speed as low as possible so as to keep the specific gravity liquid in the specific gravity liquid tank 4C as stationary as possible, and the mixture of PE flakes and PP flakes is in the middle part of the specific gravity liquid and in the central part. Carry in. The screw conveyor 4D preferably carries in the mixture gently. For example, it is preferable that the diameter of the pipe is 150 mm and the screw conveyor 4D is operated at a low speed of 40 rpm or less.

  The pipe conveyor 4E receives PE flakes with a specific gravity of 0.96, which has a specific gravity difference of only 0.025 from the specific gravity liquid with a specific gravity of 0.935, from the lower part of the specific gravity liquid, and from the bottom of the specific gravity liquid tank 4C to the dehydrator 5 side. Carry out.

  As shown in FIG. 7, the pipe conveyor 4E includes a drive chain 4E2 that is driven so as to circulate in the pipe casing 4E1, and a peripheral portion fixed to the drive chain 4E2, and a predetermined interval in the longitudinal direction of the drive chain 4E2. It has a basic structure provided with a large number of disk-shaped blades 4E3 arranged in the above.

Here, each blade 4E3 of the pipe conveyor 4E is formed with a large number of transmission holes 4E4 that allow the specific gravity liquid associated with the PE flakes to pass therethrough. In addition, a ring-shaped guide 4E5 is fixed to the peripheral edge of each blade 4E3 to slidably contact the inner surface of the pipe casing 4E1 and restrict the blade 4E3 from falling. By forming the permeation holes 4E4 in the blade 4E3, the specific gravity liquid slowly permeates from the permeation holes 4E4 even if each blade 4E3 moves, so that the convection in the specific gravity liquid can be suppressed as much as possible, and PE flakes can be prevented. It can be quickly settled while carrying out.
The blade 4E3 only needs to be capable of transmitting the specific gravity liquid, and may have an appropriate net structure. Further, the size and number of the holes of the transmission holes 4E4 may be determined according to the size of the PE flakes, the speed of the blade 4E3, and the like.

  The rake-equipped conveyor 4F scrapes PP flakes having a specific gravity of 0.91 having a specific gravity difference of only 0.025 from the specific gravity liquid having a specific gravity of 0.935 from the upper layer portion of the specific gravity liquid and transports them to the dehydrator 7 side.

As shown in FIG. 8, this rake-equipped conveyor 4F has a structure in which a plurality of rakes 4F1 are arranged at predetermined intervals, and the movement line of each rake 4F1 is the upper layer of the specific gravity liquid in the specific gravity tank 4C. The PP flakes that have floated on the part are set to be lifted upward along the inclined receiving plate 4C1 provided continuously at the upper part of the specific gravity liquid tank 4C.
It is preferable that each blade 4E3 of the pipe conveyor 4E and each rake 4F1 of the conveyor 4F with a rake move at a low speed as much as possible so as to keep the specific gravity liquid in the specific gravity liquid tank 4C as stationary as possible. For example, the moving speed of each blade 4E3 of the pipe conveyor 4E is preferably 3 m / min or less, and the moving speed of each rake 4F1 of the rake conveyor 4F is preferably 10 m / min or less.

  Here, the specific gravity sorting device 4 is provided with a specific gravity liquid preliminary tank 4H configured to circulate the specific gravity liquid in the specific gravity liquid tank 4C through the circulation pipe 4G. A valve 4J and a motor pump 4K are installed.

  Further, as shown in FIG. 9, the specific gravity sorter 4 includes a specific gravity meter 4L for measuring the specific gravity of the specific gravity liquid stored in the specific gravity liquid reserve tank 4H, and isopropyl alcohol (IPA) as a specific gravity liquid raw material. An IPA tank 4N that can be supplied to the liquid reserve tank 4H via the supply pipe 4M is attached.

  The dehydrating device 5 receives the PE flakes carried out by the pipe conveyor 4E with the specific gravity attached thereto via the hopper 5A. The dehydrating device 5 dehydrates the specific gravity liquid adhering to the PE flakes by centrifugal action, and supplies the dehydrated PE flakes into the cyclone 6A of the recovery weighing device 6 by the blower 5B.

  On the other hand, the dehydrator 7 receives PP flakes scraped out by the conveyor 4F with a rake with the specific gravity liquid attached thereto via the inclined duct 7A. The dehydrating device 7 dehydrates the specific gravity liquid adhering to the PP flakes by centrifugal action, and supplies the dehydrated PP flakes into the cyclone 8A of the recovery weighing device 8 by the blower 7B.

  As shown in FIG. 1, the collection and weighing device 6 includes a cyclone 6A that removes air from the PE flakes blown by the blower 5B of the dehydrator 5, and a hopper-type stock tank 6B into which PE flakes are charged from the cyclone 6A. And a weighing machine 6D for weighing PE flakes packed in the flexible container 6C from the stock tank 6B together with the flexible container 6C.

  On the other hand, the collection and weighing device 8 includes a cyclone 8A that removes air from the PP flakes blown by the blower 7B of the dewatering device 7, a hopper-type stock tank 8B into which PP flakes are charged from the cyclone 8A, and the stock tank. A weighing machine 8D for weighing the PP flakes packed in the flexible container 8C from 8B together with the flexible container 8C.

  In the waste resin flake sorting line configured as described above, when the raw material supply device 1 supplies a mixture of PE flakes, PP flakes, PET flakes, and PS flakes to the water sorting device 2, the water sorting device 2 has a large specific gravity. The PET flakes and PS flakes are collected as foreign matters, and the PE flakes and PP flakes are carried out to the dehydrator 3 side.

  Subsequently, the dewatering device 3 dewaters the sorted water adhering to the PE flakes and PP flakes, and supplies the dehydrated PE flakes and PP flakes mixture to the specific gravity sorting device 4. Then, the specific gravity sorting device 4 sorts PE flakes having a large specific gravity and PP flakes having a low specific gravity, carries out the PE flakes having a high specific gravity to the dehydrating device 5 side, and carries out the PP flakes having a low specific gravity to the dehydrating device 7 side. To do.

  Along with this, the dehydrating device 5 dehydrates the specific gravity liquid adhering to the PE flakes, and supplies the dehydrated PE flakes to the recovery weighing device 6. Further, the dehydrating device 7 dehydrates the specific gravity liquid adhering to the PP flakes, and supplies the dehydrated PP flakes to the recovery weighing device 8.

  Then, the collected and weighed device 8 packs the dehydrated PE flakes in the flexible container 6C, and weighs the flexible container 6C together. The dewatered PP flakes are packed into the flexible container 8C by the collection and weighing device 8 and weighed together with the flexible container 8C.

  Here, in the specific gravity sorting device 4 of one embodiment, the screw conveyor 4D gently mixes the mixture of the dehydrated PE flakes and PP flakes into the middle layer of the specific gravity liquid in the specific gravity liquid tank 4C, preferably 40 rpm or less. Carry in at the rotation speed. By using the screw conveyor 4D as the carrying-in means, the mixture of PE flakes and PP flakes can be gently carried into the center of the tank. Accordingly, PE flakes having a specific gravity of 0.96 start to settle from the middle layer of the specific gravity liquid having a specific gravity of about 0.935 in a substantially stationary state, and PP flakes having a specific gravity of 0.91 start to float. For this reason, the mixture of PE flakes and PP flakes having a specific gravity difference of 0.05 is separated efficiently in a short time.

  Then, each blade 4E3 of the pipe conveyor 4E gently receives the PE flakes having a specific gravity of 0.96 settled in the lower layer portion of the specific gravity liquid, preferably at a blade speed of 4 m / min or less, and dehydrates from the bottom of the specific gravity liquid tank 4C. Carry out to the 5th side. Further, PP flakes having a specific gravity of 0.91 floating on the upper layer portion of the specific gravity liquid are scraped out at a paddle moving speed of 10 m / min or less by the rake 4F1 of the conveyor 4F with rake and carried out to the dehydrator 7 side.

  Therefore, according to the specific gravity sorting device 4 of one embodiment, since the specific gravity liquid tank is substantially in a stationary state, the specific gravity difference is 0.05, and a mixture of minute PE flakes and PP flakes can be obtained in a short time. Specific gravity can be selected efficiently.

  Further, in the specific gravity sorting device 4 of one embodiment, the conveyor 4F with a rake scrapes the PP flakes floating on the upper layer portion of the specific gravity liquid upward along the inclined receiving plate 4C1 continuously provided above the specific gravity liquid tank 4C. In order to fry, the specific gravity liquid adhering to the PP flakes is recovered in the specific gravity liquid tank 4C by flowing down along the inclined receiving plate 4C1. Therefore, it is possible to reduce the amount of the specific gravity liquid taken out.

  Furthermore, in the specific gravity sorting device 4 of one embodiment, the specific gravity liquid in the specific gravity liquid tank 4C is accommodated in the specific gravity liquid preliminary tank 4H configured to circulate through the circulation pipe 4G and the specific gravity liquid preliminary tank 4H. A specific gravity meter 4L for measuring the specific gravity of the specific gravity liquid and an IPA tank 4N capable of supplying isopropyl alcohol (IPA), which is a raw material of the specific gravity liquid, to the specific gravity liquid reserve tank 4H via the supply pipe 4M are attached. The specific gravity of the specific gravity liquid in the specific gravity tank 4C can be managed accurately.

It is a mimetic diagram showing a waste resin flake sorting line provided with a specific gravity sorter for waste resin flakes concerning one embodiment of this invention. It is a top view which shows the arrangement | positioning relationship of the waste resin flake selection line shown in FIG. It is a front view of the raw material supply apparatus 1 shown in FIG. 1 and FIG. FIG. 3 is a front view of the water sorting apparatus 2 shown in FIGS. 1 and 2. FIG. 3 is a side view of the specific gravity sorting device 4 shown in FIGS. 1 and 2. FIG. 3 is a front view of a specific gravity sorting device 4 shown in FIGS. 1 and 2. It is a partial expansion perspective view which shows the internal structure of the pipe conveyor shown in FIG. It is a partial expanded sectional view which shows schematic structure of the conveyor with a rake shown in FIG. FIG. 7 is a partial side view of the vicinity of a specific gravity liquid reserve tank shown in FIG. 6.

Explanation of symbols

1: Raw material supply device 2: Water sorting device 3: Dehydration device 4: Specific gravity sorting device 4A: Cyclone 4B: Stock tank 4C: Specific gravity liquid tank 4D: Screw conveyor 4E: Pipe conveyor 4F: Conveyor with rake 4G: Circulation pipe 4H: Specific gravity liquid reserve tank 4J: Electric valve 4K: Motor pump 4L: Hydrometer 4M: Supply pipe 4N: IPA tank 5: Dehydrator 5A: Hopper 5B: Blower 6: Recovery meter 7: Dehydrator 7A: Inclined duct 7B: Blower 8: Recovery weighing device

Claims (5)

A specific gravity sorting device for waste resin flakes that sorts a mixture of waste resin flakes with a specific gravity liquid in a specific gravity liquid tank,
A screw conveyor capable of carrying the mixture of the waste resin flakes into the middle layer of the specific gravity liquid in the specific gravity liquid tank;
A pipe conveyor capable of receiving waste resin flakes having a large specific gravity that has settled in the lower layer of the specific gravity liquid and carrying it out from the bottom of the specific gravity liquid tank;
A specific gravity sorting apparatus for waste resin flakes, comprising: a conveyor with a rake capable of scraping out waste resin flakes having a small specific gravity that has floated on an upper layer portion of the specific gravity liquid and carrying them out from an upper portion of the specific gravity liquid tank.   2. The pipe conveyor according to claim 1, wherein a plurality of blades are arranged in a drive chain that circulates in a pipe casing, and the blades are formed with permeation holes that allow a specific gravity liquid to pass therethrough. Specific gravity sorter for waste resin flakes.   The conveyor with a rake is configured to scrape the waste resin flakes having a small specific gravity floating on the upper layer of the specific gravity liquid upward along an inclined receiving plate installed in the upper part of the specific gravity liquid tank. The specific gravity sorter for waste resin flakes according to claim 1 or 2.   The specific gravity liquid preliminary tank configured to allow the specific gravity liquid in the specific gravity liquid tank to circulate, and a specific gravity meter for measuring the specific gravity of the specific gravity liquid in the specific gravity liquid preliminary tank is attached. The specific gravity sorting apparatus for waste resin flakes in any one of 1-3.   The waste resin flakes specific gravity sorting apparatus according to any one of claims 1 to 4, wherein a component of the waste resin flakes having a large specific gravity is polyethylene and a component of the waste resin flakes having a low specific gravity is polypropylene.

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