JP2004130234A - Volume reduction machine of plastic - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress a temperature increase of a rotating shaft arranged in a crushing section of a plastic volume reduction machine. <P>SOLUTION: The plastic volume reduction machine 1 is equipped with a crushing section 2 for crushing foamed plastics and a compression section 5 for compressing the crushed foamed plastics. In the crushing section 2, crushing arms 9 for crushing foamed plastics and a hollow rotating shaft 8 equipped with a screw blade 10 for transferring the crushed foamed plastics to the side of the compression section 5 are arranged. Through the hollow of the rotating shaft 8, a coolant flows. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a plastic volume reducer that is crushed and compressed in order to reduce the volume of plastic having a very low bulk density, such as foamed plastic.
[0002]
[Prior art]
Used or unneeded plastics are discharged as waste plastic from general households and various business establishments, but usually they are collected by collection vehicles and transported to treatment facilities where they are incinerated or Alternatively, it is thermally decomposed by a pyrolysis device and recycled as resources such as fuel and monomer components.
[0003]
Waste plastics include polystyrene, polyethylene, polypropylene, and polyvinyl chloride, and they have various forms such as hard plastics, sheets, and foams. Among them, foamed plastic is widely used as a cushioning material for food trays and packing, and accordingly, a large amount of waste foamed plastic is discharged, and among them, expanded polystyrene (so-called styrene foam) accounts for a large proportion.
[0004]
To collect and recycle waste foamed plastic (hereinafter simply referred to as foamed plastic) as fuel or monomer, for example, requires various operations and treatments such as transportation, storage, and thermal decomposition. However, since foamed plastic is bulky, Work and processing becomes extremely difficult. Therefore, it has been proposed to install a volume reducer in a business establishment or an accumulation place that discharges foamed plastic, and to significantly reduce the volume before carrying out transportation, storage, heat treatment, or thermal decomposition treatment.
[0005]
Conventionally known volume reducers include a crushing / melting type and a crushing / compression type. The former requires a volume reducing solution and has a drawback that running costs are increased. On the other hand, the latter does not require a volume reducing solution, is easy to handle, and can reduce the running cost.
[0006]
Such a pulverizing / compression type volume reducer has already been proposed as a plastics volume reducer by a part of the present applicant (for example, see Patent Documents 1 and 2).
[0007]
The volume reduction machine disclosed in Patent Document 2 has a hopper for charging plastics, a pulverizing unit disposed below the hopper, and a compression unit disposed in front of the hopper. The crushing section has a large number of crushing arms implanted on a rotating shaft, screw blades for feeding plastics forward, and a crushing plate protrudingly fixed in the crushing section surrounding them. The respective crushing arms are arranged apart from each other in the axial direction and the circumferential direction of the rotating shaft, and the crushing plates are arranged in a vertical bar shape at a predetermined distance in the front-rear direction so as not to interfere with the crushing arm and the screw blade.
[0008]
In the compression section, a truncated pyramid-shaped compression cylinder surrounds the screw blade. Then, the plastic such as foamed styrene introduced from the hopper is crushed in the crushing section and sent forward by the screw blade. Then, it is press-fitted into a compression cylinder having a truncated pyramid shape at the front compression portion, compressed, and reduced in volume.
A discharge cylinder having a polygonal cross section is provided at the tip of the compression section, from which the pulverized and compressed foamed plastic is extruded into a rod shape, then cut into a predetermined length by a cutter, and discharged from the volume reduction machine.
[0009]
[Patent Document 1]
JP 2002-66370 A [Patent Document 2]
JP-A-2002-79399
The proposed volume reducer is provided with a common rotary shaft coaxially provided with a crushing arm for crushing the foamed plastic for compactness and a screw blade for transferring the crushed foamed plastic toward the discharge cylinder. Is done.
This volume reducer has the advantage that the size of the apparatus can be reduced and the volume reduction cost can be reduced because the foamed plastic is crushed and the crushed foamed plastic is transferred by one rotating shaft.
[0011]
[Problems to be solved by the invention]
However, when the volume reduction processing of the foamed plastic is continuously performed for a long time using the common rotary shaft type volume reducer proposed in the above publication, the crushing and transfer of the foamed plastic are performed in a narrow space for a long time. It has been found that the temperature of the foamed plastic staying around the rotating shaft increases due to the frictional heat generated by the operation, and thereby the temperature of the rotating shaft also increases significantly. The rotating shaft tends to heat more downstream in the conveying direction of the screw blade. This is presumed to be due to the fact that the foamed plastic is compressed further downstream.
[0012]
When the temperature of the rotating shaft rises in this way, a part of the pulverized foamed plastic that stays around the rotating shaft is melted, so that there is a problem that the melt adheres to the rotating shaft. At the same time, in the compression step, which is a post-process of the pulverization process, the non-uniform crushed material mixed with the melt is subjected to compression processing, and finally the particle size and hardness of the reduced volume discharged from the volume reduction machine are reduced. Variations occur.
[0013]
Such a reduced volume having a variation in particle size and hardness is not preferable because it has a bad influence on the subsequent thermal decomposition treatment and the like. Therefore, an object of the present invention is to solve the problems in such a common rotary shaft type volume reducer, and to provide a new volume reducer for that purpose.
[0014]
[Means for Solving the Problems]
The invention according to claim 1, which solves the above problem, includes a crushing unit (2) for crushing the foamed plastic, and a compression unit (5) for compressing the crushed foamed plastic,
A rotating shaft (8) provided with a crushing arm (9) for crushing the foamed plastic and a screw blade (10) for transferring the crushed plastic to the compression unit (5) is disposed in the crushing section (2). Plastic volume reducer
A plastic volume reducer characterized in that the rotary shaft (8) is a hollow shaft and a cooling medium can flow through the hollow portion. (Claim 1)
[0015]
The invention according to claim 2 includes a crushing section (2) for crushing the foamed plastic, and a compression section (5) for compressing the crushed foamed plastic.
A rotating shaft (8) provided with a crushing arm (9) for crushing the foamed plastic and a screw blade (10) for transferring the crushed plastic to the compression unit (5) is disposed in the crushing section (2). Plastic volume reducer
A plastic volume reducer characterized in that the rotary shaft (8) is a hollow shaft and a convective liquid is sealed in the hollow portion.
According to a third aspect of the present invention, in the configuration of the first aspect, the rotary shaft (8) is provided with a nozzle hole (20a) (20b), and the nozzle hole (20a) (20b) is connected to the rotary shaft (8). It can be configured such that at least a part of the cooling medium flowing inside can be ejected.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a partially cutaway front view of a volume reducer according to the present invention, FIG. 2 is a plan view thereof, and FIG. 3 is a left side view of FIG. In these figures, a volume reducing machine 1 includes a crushing unit 2, a hopper unit 3 provided above the crushing unit 2, an input port 4 provided above the hopper unit 3, and a taper communicating with the front of the crushing unit 2. The compression unit 5 has a truncated pyramid cylindrical shape, and a discharge tube 6 communicating with the outlet side of the compression unit 5.
[0017]
Further, a cutter device (not shown) for cutting the plastic extruded into a rod into a predetermined length is provided on the outlet side of the discharge cylinder 6 having a polygonal cross section. On the other hand, a plurality of casters 7 for moving the apparatus are provided at the bottom of the crushing unit 2. An operation unit 30 (FIG. 3) for performing a driving operation is attached to a side portion of the hopper unit 3.
[0018]
A rotating shaft 8 is arranged in the crushing section 2 in the horizontal direction. The rotating shaft 8 is made of a highly rigid pipe material such as stainless steel and has a plurality of elongated metal crushing arms 9 radially extending radially around its outer periphery at predetermined intervals. Screw blade 10 is provided coaxially in the axial direction. A crushing plate 9a is protruded and fixed in a crushing portion surrounding them. As shown in FIG. 2, the crushing plates 9 a are arranged in a vertical cross at a predetermined distance in the front-rear direction so as not to interfere with the crushing arm 9 and the screw blade 10. The compression section 5 is composed of a tapered truncated pyramid-shaped cylinder and a tapered screw blade disposed therein. That is, a tapered frustum of a pyramid surrounds the screw blade. The screw blade of the compression section 5 has an outer periphery substantially aligned with the truncated pyramid-shaped cylinder, and has a tapered shape in which the radius decreases toward the tip.
[0019]
The crushing arm 9 finely crushes the foamed plastic supplied from the hopper 3 with an impact force between the crushing plate 9a and the crushing plate 9a, and the crushed foamed plastic piece is transferred to the discharge cylinder 6 side by the screw blade 10. The compression section 5 compresses and reduces the volume of the crushed foamed plastic piece and sends it out of the discharge cylinder 6 to the outlet side in the form of a polygonal rod.
The rod-shaped compressed plastic is cut into a predetermined length by a cutter device provided on the outlet side and discharged.
These structures and operations are the same as those of the plastics volume reducer described in JP-A-2002-66370.
[0020]
Next, the rotating shaft 8 is rotatably supported by the first bearing 11 and the second bearing 12, and is rotated at a low speed by the driving unit 13. Note that FIG. 3 shows a support arm 12a that supports the second bearing portion 12.
The drive unit 13 is attached to the rear end (the right side surface in FIG. 1) of the crushing unit 2 and has a drive motor 14 and a speed reduction mechanism 15 connected to an output shaft thereof. As an example, the reduction mechanism 15 utilizes a worm gear mechanism 16, whereby the output shaft of the motor and the rotating shaft 8 are connected.
The rotating shaft 8 is a hollow shaft, and a hose 17 for supplying a cooling refrigerant from a refrigerant tank (not shown) and a hose 18 for returning the refrigerant whose temperature has been raised by heat exchange to the refrigerant tank are connected to the hollow portion. Is done.
[0021]
FIG. 4 is an enlarged front view showing a part of the rotating shaft 8, the crushing arm 9, and the screw blade 10 shown in FIG. 1, and FIG. 5 is an axial direction showing the rotating shaft 8 in FIG. It is sectional drawing.
First, as shown in FIG. 4, the rotating shaft 8 is rotatably and coaxially fixed to a fixed cylindrical portion 21 fixed to the rear of the crushing portion 2 via a rotary seal portion 22 at a distal end portion of the fixed cylindrical portion 21. And a rotating cylinder portion 20 that is continuous with The outer periphery of the front end portion and the outer periphery of the rear end portion of the rotary cylinder portion 20 are supported by a first bearing portion 11 and a second bearing portion 12. A plurality of elongated crushing arms 9 and a screw blade 10 are fixed to an outer peripheral portion of the rotary cylinder 20.
[0022]
Next, as shown in FIG. 5, the front end of the hollow cylindrical rotary cylinder 20 is closed by a lid 23, and a rotary seal 22 made of an O-ring is provided inside the rear end of the rotary cylindrical section 20. The distal end portion of the fixed cylindrical portion 21 is inserted through. A fixing ring 25 coaxially connected to the inner cylinder 24 is inserted and fixed inside the rear end of the fixed cylinder 21, and the inner cylinder 24 extends from the fixed cylinder 21 to the vicinity of the distal end of the rotary cylinder 20. Has been extended.
[0023]
One end of an elbow 26 is screwed into an inner thread formed at the rear end of the fixing ring 25, and the refrigerant supply side hose 17 is connected via a hose nipple 27 screwed to the other end of the elbow 26. . Further, a socket 28 is fixed to a through hole provided in an intermediate portion of the fixed cylindrical portion 21, and the hose 18 on the refrigerant return side is connected via a hose nipple 29 screwed to an inner thread portion formed in the socket 28.
[0024]
【how to use】
Next, a method for reducing the volume of foamed plastic such as waste expanded polystyrene by the volume reducing machine shown in FIG. 1 will be described. First, a coolant such as cooling water or cooling air stored in a coolant tank (not shown) is circulated inside the rotating shaft 8. That is, when the refrigerant is supplied from the refrigerant tank to the inside of the fixed tubular portion 21 (FIG. 5) through the hose 17 by a pump (not shown), the coolant passes through the internal space of the inner tubular body 24 arranged in the fixed tubular portion 21 and rotates. 20 and returns to the refrigerant tank from the hose 18 through the space between the outer peripheral surface of the inner cylindrical body 24 and the inner wall surface of the rotary cylindrical part 20.
[0025]
Next, the foamed plastic is put into the hopper 3 from the inlet 4. The foamed plastic in the hopper section 3 enters the lower crushing section 2 where it is finely crushed. That is, the drive motor 14 of the drive unit 13 is started by operating the start switch provided on the operation unit 30 (FIG. 3), and the rotary cylinder unit 20 of the rotary shaft 8 rotates via the speed reduction mechanism 15. Then, the crushing arm 9 rotates, and the foamed plastic is finely pulverized by the impact force between the crushing arm 9 and the crushing plate 9a.
[0026]
The pulverized foamed plastic is agitated by the screw blades 10 provided on the rotary cylinder 20 and moves leftward in the axial direction, and is pushed into the compression unit 5 to reduce the volume. The plastic that has been compressed and reduced in volume moves from the outlet side of the compression section 5 to the discharge cylinder 6, is cut into a predetermined length by a cutter provided in the middle thereof, and is discharged to the outside from the outlet as a short rectangular rod-shaped reduced volume.
[0027]
When a large amount of foamed plastic is continuously crushed by the crushing arm 9 in a narrow place surrounding the rotating shaft 8 and stirred by the screw blade 10, a large amount of frictional heat is generated. This heat accumulates inside the crushing section 2, particularly near the rotating shaft 8, and significantly raises the internal temperature. However, in the present embodiment, since the rotating shaft 8 is cooled by the refrigerant circulating inside, the temperature rise of the rotating shaft 8 is efficiently suppressed. Therefore, various problems caused by a rise in temperature as in the related art do not occur.
[0028]
FIG. 6 shows a modification of the rotating shaft 8 shown in FIG. This example differs from the example of FIG. 5 in that a nozzle hole 20a is provided in a portion of a lid 23 that closes a tip portion of the rotary cylinder portion 20, and a nozzle hole 20b is provided in a side wall portion of the rotary cylinder portion 20. is there. Otherwise, the configuration is substantially the same as that of FIG. 5, and the same parts as those of FIG.
[0029]
Next, the cooling operation of the rotating shaft 8 in FIG. 6 will be described. First, the refrigerant to be supplied to the fixed cylindrical portion 21 may be one which may be ejected into the crushing portion 2, for example, outside air or air cooled by a refrigerator or the like. Next, the refrigerant supplied to the fixed cylindrical portion 21 flows to the tip of the rotary cylindrical portion 20, and is jetted from the nozzle holes 20 a and 20 b into the inside of the crushing portion 2, particularly around the rotary shaft 8, and around the rotary shaft 8. Cool the parts.
[0030]
In FIG. 6, a nozzle hole 20 a of the lid 23 provided at the tip of the rotary cylinder 20 and a nozzle hole 20 b of the side wall of the rotary cylinder 20 are provided. It can be provided on only one of them, or it can be provided at a plurality of locations along the vertical and horizontal directions of the side wall or along the axial direction.
When the nozzle hole is provided as shown in FIG. 6, the rotating shaft 8 is simultaneously cooled from the inside and the outside, so that the cooling is more effectively performed than the example of FIG.
[0031]
FIG. 7 shows still another modification of the rotary shaft 8 shown in FIG. In this example, one end of a hollow rotary shaft 8 is closed, and the other end is openably and closably closed by an end cover 31, and a convective liquid such as water or an antifreeze is sealed inside.
According to the experiment, even in the case of FIG. 7 in which the liquid is filled in the hollow rotary shaft without taking out the liquid to the outside as in the examples of FIGS. The temperature of the part decreases. As a result, there was no problem that a part of the pulverized foamed plastic staying around the rotating shaft was melted. Although the reason is not clear, the heat at the tip of the rotating shaft, which becomes particularly hot, is transferred to the liquid inside the hollow rotating shaft, and the liquid is convected, so that heat is radiated at the low temperature part of the rotating shaft. Seem.
[0032]
【The invention's effect】
As described above, the foamed plastic volume reducer according to the present invention includes a rotating shaft provided with a crushing arm and a screw blade in a crushing section, the rotating shaft being a hollow shaft, and a cooling medium being provided in a hollow portion of the rotating shaft. So that the temperature rise around the rotating shaft due to frictional heat can be effectively suppressed even if the volume reduction of the foamed plastic is performed continuously for a long time. No problem such as sticking to the rotating shaft occurs, and there is no variation in the particle size and hardness of the reduced volume discharged from the volume reducing machine.
[0033]
As described above, it has been confirmed by experiments that the rotary shaft (8) may be a hollow shaft and a convective liquid may be sealed in the hollow portion.
Next, in the volume reduction device, a nozzle hole may be provided in the rotating shaft, and at least a part of the cooling medium flowing through the inside of the rotating shaft may be ejected from the nozzle hole into the crushing unit. With such a configuration, the rotating shaft can be simultaneously cooled from inside and outside, and the rotating shaft can be more effectively cooled.
[Brief description of the drawings]
FIG. 1 is a partially cutaway front view of a volume reducing machine according to the present invention.
FIG. 2 is a plan view of the volume reducing machine.
FIG. 3 is a left side view of FIG. 1;
FIG. 4 is an enlarged front view showing a part of a rotating shaft 8, a crushing arm 9, and a screw blade 10 shown in FIG. 1;
FIG. 5 is an axial cross-sectional view showing the rotary shaft 8 in FIG. 4 in a further enlarged manner.
FIG. 6 is an axial sectional view showing a modification of the rotating shaft shown in FIG. 5;
FIG. 7 is an axial sectional view showing a further modified example of the rotating shaft shown in FIG. 5;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Volume reduction machine 2 Crushing part 3 Hopper part 4 Inlet 5 Compressor 6 Discharge cylinder 7 Caster 8 Rotary shaft 9 Crushing arm 9a Crushing plate 10 Screw blade 11 First bearing part 12 Second bearing part 12a Support arm 13 Drive Part 14 Drive motor 15 Reduction mechanism 16 Worm gear mechanism 17, 18 Hose 20 Rotating cylinder part 20a Nozzle hole 20b Nozzle hole 21 Fixed cylinder part 22 Rotary seal part 23 Lid 24 Inner cylinder 25 Fixing ring 26 Elbow 27 Hose nipple 28 Socket 29 Hose nipple 30 Operation unit 31 End cover

Claims (3)

A crushing section (2) for crushing the foamed plastic; and a compression section (5) for compressing the crushed foamed plastic.
A rotating shaft (8) provided with a crushing arm (9) for crushing the foamed plastic and a screw blade (10) for transferring the crushed plastic to the compression unit (5) is disposed in the crushing section (2). Plastic volume reducer
A plastic volume reducing machine characterized in that the rotary shaft (8) is a hollow shaft and a cooling medium can flow through the hollow portion. A crushing section (2) for crushing the foamed plastic; and a compression section (5) for compressing the crushed foamed plastic.
A rotating shaft (8) provided with a crushing arm (9) for crushing the foamed plastic and a screw blade (10) for transferring the crushed plastic to the compression unit (5) is disposed in the crushing section (2). Plastic volume reducer
A plastic volume reducer characterized in that the rotating shaft (8) is a hollow shaft, and a convective liquid is sealed in the hollow portion. The rotary shaft (8)} according to claim 1, wherein the rotary shaft (8)} is provided with a nozzle hole (20a) {(20b)}, and at least a part of the cooling medium flowing from the nozzle hole (20a) {(20b)} to the inside of the rotary shaft (8)}. A plastic volume reducer characterized by being configured to be able to squirt.

Images