JPH11348038A - Cutting equipment for volume reduction molding of waste plastic - Google Patents

Abstract

(57) [Problem] The shape of a conventional cutting blade is a knife-edge shape, so that rod-shaped plastic discharged in a molten state easily adheres to the cutting blade, and the degree of deformation of a cut rod-like solid material. There was a problem that it was big. SOLUTION: A volume reduction molding machine of a single-screw or twin-screw extruder is used for volume reduction molding of various types of thermoplastic waste plastics, and then cut to a predetermined size. A cutting device, wherein a plurality of nozzles are arranged on a pitch circle of a die of the volume reduction molding machine, and are radially extended from a boss portion of a cutting member formed on the same axis as a screw of the volume reduction molding machine. A plurality of cutting blades, which are disposed at a fixed distance from the end face of the nozzle and are made of steel wire as a main part, are attached to the tip of the arm portion to be cut, and the cutting is rotated along the end face of the nozzle. The blade cuts the rod-like discharge material discharged from the nozzle opening of the nozzle into a predetermined length.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the compression, melting and melting of various thermoplastic waste plastics from homes and factories.
The present invention relates to a cutting device for volume-reduced molding of waste plastic, which is cut into a predetermined size after volume reduction to obtain a high-density rod-like solid.

[0002]

2. Description of the Related Art Municipal garbage including various plastics discharged from homes and factories is treated by incineration, landfill, resource recovery and the like. Each of these treatments has its own problems, but the main causes are various plastics in the garbage.For example, melting during incineration, furnace clogging due to adhesion, furnace damage due to local heating, chlorine gas and dioxin, etc. Generation of harmful gas. In addition, many waste plastics are bulky, such as foamed polystyrene, sheets, bags, etc., which require transportation costs for landfill disposal, and are exposed from the surface even after landfill and are scattered by the wind, polluting the environment. Sometimes. Recently, various methods of separating and collecting and reusing waste plastic have been proposed from the viewpoint of effective use of resources. In order to reuse waste plastic, it is essential to reduce the volume of bulky waste plastic. As a general method of compressing, melting, and reducing the volume of various thermoplastic waste plastics, a single-screw or twin-screw extruder is used as a waste plastic volume reduction molding machine.

[0003]

A rod-shaped plastic discharged in a molten state from a die of a waste plastic volume reducing molding machine is cut into a predetermined length by a rotating cutting blade, and then cooled to obtain a rod-shaped solid. Becomes In a conventional waste plastic volume reduction molding machine, as shown in FIG. 7, a cutting device having a knife edge-shaped cutting blade has been used for cutting. As shown in FIG. 6 of JP-A-8-197542, FIG. 2 of JP-B-7-102606, and FIG. 1 of JP-A-6-39179, various cutting devices are used in a conventional waste plastic volume reduction molding machine. However, all of the cutting blades have a knife-edge shape, and have various problems related to cutting.
For example, bar-shaped plastic discharged in a molten state from a die adheres to a knife-edge-shaped cutting blade and hinders continuous operation, or the deformation of a bar-shaped solid cut by cutting resistance increases and quality is reduced. There was a problem.

[0004]

In order to solve the above problems, according to the present invention, in the first invention, various thermoplastic resins are reduced by a volume reducing molding machine of a single-screw or twin-screw extruder. A cutting device for volume reduction molding of waste plastic, which is configured to cut waste plastic into a predetermined size after volume reduction molding, wherein a plurality of nozzles are arranged on a pitch circle of a die of the volume reduction molding machine. A steel wire disposed at a distance from the end face of the nozzle at a distal end of an arm portion radially extending from a boss portion of a cutting member formed coaxially with a screw of the volume reducing molding machine, A plurality of cutting blades, each of which is a cutting main part, are attached, and the cutting blade rotating along the end face of the nozzle cuts the rod-shaped discharge material discharged from the nozzle opening of the nozzle into a predetermined length. did.

[0005] In the second invention, which is mainly based on the first invention, the mounting position of the cutting blade for cutting the rod-shaped ejected material is changed according to the protruding length of the nozzle changed by the nozzle replacement.
A plurality of cutting blade mounting holes are provided at different positions in the screw axis direction at the distal end of the arm portion of the cutting member so that the distance between the end face of the nozzle and the cutting blade can be changed to a constant position.

[0006]

Embodiments of the present invention will be described below in detail with reference to the drawings. 1 to 6 relate to an embodiment of the present invention. FIG. 1 is a side sectional view of an apparatus for reducing the volume of waste plastic, FIG. 2 is a front view of FIG. 1, and FIG. 3 is a material supply port of FIG. , FIG. 4 is a detailed view of the screw dividing part and the cutting unit part of FIG. 1, FIG. 5 is a circumferential development view showing a phase of a screw flight in the screw dividing part, and FIG. 6 is a waste screw in a twin-screw extruder. FIG. 3 is a flow diagram of a piping system for indirectly heating or cooling plastic.

As shown in FIG. 1, a casing 10 of a twin-screw extruder 90 is installed on a machine base 1, and two screws 13 are rotatably inserted inside the casing 10. Further, a screw element 14 having two screw flights 13a is fastened concentrically to the screw 13 at the tip end side of the screw 13 as shown in a circumferential development of FIG. Also, the casing 1
A material supply port 6 is opened at the upper surface on the base end side of the die 0, and a die 16A and a die end plate 16B are attached to the casing 10 by bolts 19 at the distal end surface. further,
A nozzle 17 is inserted into a plurality of concave holes formed in the die 16A and the die end plate 16B. A hopper (not shown) is connected to the material supply port 6, and waste plastic is supplied to the hopper from a mixing and blending facility (not shown).

Further, as shown in FIG.
The bearing housing 4 is connected to the base end of the screw 13 by a flange, and the drive shaft 5 connected to the base end of the screw 13 by the flange is supported by the bearing housing 4 via a bearing. Further, the drive shaft 5 is connected to the driving shaft 2 via a coupling 3, and the driving shaft 2 is connected to a gear device and an inverter motor (not shown). The drive shaft 2, the coupling 3, the drive shaft 5, the screw 1
Reference numeral 3 denotes two sets arranged side by side, and is configured to rotate in mutually opposite directions by a gear device and an inverter motor (not shown). For this reason, as shown in FIG. 3, in connection with the rotation direction of the screw 13 being reversed, the two screws 13 are mutually opposite screw flights 13.
a.

Next, a structure for indirectly heating or cooling the waste plastic in the casing 10 from outside the casing 10 will be described.

As shown in FIG. 1, a jacket 11 is provided on an outer peripheral surface of a casing 10. The jacket 11
The jacket 11 is provided with an inlet flange 11a for selectively introducing hot water or steam and an outlet flange 11b for discharging hot water or steam from the jacket 11. As shown in FIGS. 1 and 2, a band heater 24 is fastened to the outer peripheral surfaces of the die 16A and the die end plate 16B. Further, as shown in FIG.
An insertion hole for a temperature detector is formed in the die end plate 16B and the outer peripheral upper surface of the distal end portion of the casing 10, and the temperature detector 12 is mounted in the insertion hole. As shown in FIG. A screw hole for a pressure detector penetrating the die end plate 16B and the die 16A is formed from the end face side of the die 16B, and a pressure detector 52 is mounted in the screw hole.

As shown in FIG. 6, a heating / cooling piping system 40 for selectively introducing and discharging hot water or steam is connected to the inlet flange 11a and the outlet flange 11b of the jacket 11. First, a pipe 46 connected to the inlet flange 11a is branched into two pipes. One pipe 46 is connected to a hot water supply line (not shown) via a hot water supply valve 41, and the other pipe 46 is provided via a steam supply valve 43. Connected to a steam supply source (not shown). A pipe 46 connected to the outlet flange 11b is branched into two pipes, one pipe 46 is connected to a hot water return line (not shown) via a hot water discharge valve 42, and the other pipe 46 is connected to a steam discharge valve 44. Connected to the steam trap 45.

Next, the nozzle 1 which is a feature of the present invention is described.
The structure of the cutting unit 30 that cuts the rod-like discharge material discharged from the nozzle opening 17a of No. 7 will be described below.

As shown in FIG. 4, a concave hole and a key groove are formed in the distal end surface of the screw element 14. The base end of the shaft 31 is inserted into the concave hole, and the center of the shaft 31 is stopped by the key 21. It is fixed to the shaft 15 with bolts. The shaft 31 is rotatably supported by a die 16A and a die end plate 16B via a bush 32. The outer peripheral surface of the shaft 31 supported by the bush 32 is provided with a screw groove in a direction opposite to the screw flight 13a of the screw 13 and the screw element 14, and the inner peripheral surface of the bush 32 and the shaft 3
The molten plastic is prevented from leaking from the gap with the outer peripheral surface of No. 1.

Further, a cutting member 33 is fixed to a distal end surface of the shaft 31 with bolts, and a distal end of an arm 33b extending radially from a boss 33a of the cutting member 33 has a screw axial direction. Are provided with a plurality of cutting blade mounting holes 33c for mounting the cutting blade 34 at different positions. The cutting blade 34 uses a piano wire as a material of a wire 34a serving as a cutting main part, and includes a fixing bracket 34b fixed to one end of the wire 34a and a screw fitting 34c fixed to the other end of the wire 34a. With the wing nut 35 screwed with the screw fitting 34c, the cutting blade 3
Reference numeral 4 is attached to the cutting blade mounting hole 33c of the cutting member 33 with a given tension. In this way,
The cutting unit 30 composed of the shaft 31, the cutting member 33, and the cutting blade 34 is rotated in synchronization with the rotation of the screw 13 and the screw element 14, and the cutting blade 34 rotates along the end face of the nozzle 17, and the nozzle opening The rod-shaped discharge material discharged from 17a is cut by the cutting blade 34.

The volume reduction molding method of using the waste plastic volume reduction molding apparatus 100 configured as described above to reduce the volume of the waste plastic to obtain a rod-shaped solid will be described below.

Before starting the molding, the steam supply valve 43 shown in FIG.
To open piping 46, inlet flange 1 from steam supply
1a, steam is introduced into the jacket 11 and circulated, and the steam discharge valve 44 is opened to condense water from the steam trap 45 through the outlet flange 11b, the pipe 46, and the steam discharge valve 44 to the heating / cooling piping system 40. Discharge outside the system. In this manner, the casing 10 and the screw 13 are preheated from the outer peripheral surface of the casing 10, and at the same time, the band heater 24 fastened to the outer peripheral surfaces of the die 16A and the die end plate 16B is energized, and the die end plate 1
The control is performed so that the detected value of the temperature detector 12 mounted on 6B becomes a predetermined temperature. When the detected value of the temperature detector 12 attached to the casing 10 reaches a predetermined temperature, volume reduction molding of the waste plastic is started. During the molding, when the detected value of the temperature detector 12 becomes too high, steam is supplied. The valve 43 and the steam discharge valve 44 are closed and the hot water supply valve 41 is closed.
When the detected value of the temperature detector 12 becomes too low, the steam supply valve 43 and the steam discharge valve 44 are opened and the hot water supply valve 41 and the hot water discharge valve 42 are closed.

Further, the set temperature of the casing 10 can be changed depending on the type, form, or molding state of the waste plastic supplied to the material supply port 6 to stabilize volume reduction molding. In general, when a large amount of waste plastic in a lump that is hard to melt or PP resin that is hard to be softened or deformed is supplied, the set temperature of the casing 10 is set to a higher temperature, and a small piece of waste plastic that is easily melted or softened. P which is easily deformed
When a large amount of E resin or ABS resin is supplied, it is desirable to set the temperature of the casing 10 lower.

Further, in volume reduction molding of waste plastic, the type and form of waste plastic supplied to the material supply port 6 vary. Therefore, a current value slightly lower than the limit of tripping beyond the rated current value of the inverter motor is set, and when the detected current value reaches the set value, the rotation speed of the inverter motor is reduced to lower the rotation speed of the screw 13. . By doing so, the amount of waste plastic taken into the volume reduction molding machine can be reduced, and interruption of volume reduction molding due to a trip can be avoided. In addition, with respect to the steep change in the type, form, and molding state of the waste plastic supplied to the material supply port 6, mainly, the rotation speed of the screw 13 is adjusted to generate heat in the waste plastic volume reduction molding apparatus 100. Adjust the amount and for slow fluctuations,
By performing heating and cooling mainly by the jacket, stable temperature control that responds quickly and does not hunt is achieved.

Even when the screw rotation speed control and the temperature control are performed as described above, depending on the type and form of the waste plastic supplied to the material supply port 6 and the variation of the molding state, the discharged plastic is discharged from the nozzle opening 17a. The state of the rod-shaped ejection material varies slightly. Conventionally, such a change in the state of the discharged material is directly linked to a change in the cutting state, and stick-shaped plastic discharged in a molten state adheres to the cutting blade, or cutting resistance increases, and cutting cannot be performed. This made continuous cutting difficult. On the other hand, in the present invention, since the piano wire is used for the main part of the cutting blade 34, the nozzle opening 17
a cutting blade 3 for cutting a rod-like discharge material discharged from a
The contact area between the nozzle 4 and the discharge material is extremely small. As a result, the resistance at the time of cutting the ejected material is smaller than that of the conventional knife-edge-shaped cutting blade, and even if the state variation of the ejected material occurs as described above, the rod-shaped ejected in a molten state. The plastic does not adhere to the cutting blade or cannot be cut, and stable sharpness is maintained even in continuous cutting. The cut rod-like solid material is beautiful with almost no deformation. Further, in a situation where the lot of waste plastic supplied to the material supply port 6 changes and the type and form of the waste plastic are largely different, correspondingly,
It is common to carry out volume reduction molding by replacing the nozzle with a nozzle suitable for the type and form of the supplied waste plastic. However, even if the protruding length of the nozzle changes due to the nozzle replacement, the cutting member 33 is cut. Select the blade mounting hole 33c as appropriate,
The mounting position of the cutting blade 34 is determined by the end face of the nozzle 17 and the cutting blade 34.
By changing the distance to a position where the distance from the nozzle opening 17a becomes constant, the rod-shaped plastic discharged from the nozzle opening 17a can always be cut at an appropriate position, and the cutting state is stabilized.

In this embodiment, the cutting member is configured to rotate about the same axis as the screw of the twin-screw extruder. However, the present invention is not limited to this. For example,
A cutting source having a driving source different from the twin-screw extruder, a shaft rotated by the driving source, an arm extending radially from a boss connected to the shaft, and the arm A cutting unit comprising a plurality of cutting blades which are attached to the tip of the extruder and have a steel wire as a main part, and the cutting blade is separated from the nozzle end face of the twin-screw extruder by a predetermined distance. Fix to a relative position that rotates along the end face,
The same effect can be obtained by configuring the cutting blade to rotate at a different rotation speed from that of the screw of the twin-screw extruder.

Here, a description has been given of a molding example in which waste plastic is compressed, melted, and reduced in volume to obtain a high-density rod-like solid. The same effect can be obtained in molding to process into a high-density rod-shaped solid fuel that is mixed and the calorific value is adjusted.

[0022]

As described above, the present invention exerts the following excellent effects. (1) Since the cutting resistance when cutting the ejected material is smaller than that of a conventional knife-edge-shaped cutting blade, the rod-shaped plastic ejected in a molten state is cut even when the state of the ejected material changes. It does not adhere to the blade or become uncut, and stable sharpness is maintained even in continuous cutting. The cut rod-like solid material is beautiful with almost no deformation. (2) Even if the protrusion length of the nozzle changes due to nozzle replacement, the cutting blade mounting hole of the cutting member is appropriately selected, and the mounting position of the cutting blade is set to a position where the distance between the end face of the nozzle and the cutting blade is constant. By changing, the rod-shaped plastic discharged from the nozzle opening can always be cut at an appropriate position, and the cut state is stabilized.

[Brief description of the drawings]

FIG. 1 is a side sectional view of a waste plastic volume reducing molding machine according to an embodiment of the present invention.

FIG. 2 is a front view of FIG.

FIG. 3 is a detailed view of a material supply port of FIG. 1;

FIG. 4 is a detailed view of a screw dividing section and a cutting unit section of FIG. 1;

FIG. 5 is a circumferential development view showing a phase of a screw flight in a screw dividing section according to the embodiment of the present invention.

FIG. 6 is a flow chart of a piping system for indirectly heating or cooling waste plastic in a twin-screw extruder according to an embodiment of the present invention.

FIG. 7 is a detailed view of a conventional cutting unit.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Machine base 2 Drive shaft 3 Coupling 4 Bearing housing 5 Drive shaft 6 Material supply port 10 Casing (barrel) 11 Jacket 11a Inlet flange 11b Outlet flange 12 Temperature detector 13 Screw 13a Screw flight 14 Screw element 14a Inlay 14b Division surface 15 Center shaft 16A dice 16B dice end plate 17 nozzle 17a nozzle opening 19 bolt 21 key 22 key 23 key bolt 24 band heater 30 cutting unit 31 shaft 32 bush 33 cutting member 33a boss portion 33b arm portion 33c cutting blade mounting hole 34 cutting blade 34a wire 34b Fixing fitting 34c Screw fitting 35 Wing nut 40 Heating / cooling piping system 41 Hot water supply valve 42 Hot water discharge valve 43 Steam supply valve 44 Steel Steam discharge valve 45 Steam trap 46 Piping 52 Pressure detector 90 Twin screw extruder 100 Waste plastic volume reduction molding device

Claims (2)

[Claims] 1. Reduced volume molding of waste plastics in which various thermoplastic waste plastics are volume-reduced by a single-screw or twin-screw extruder volume-reduction molding machine and then cut to a fixed size. A plurality of nozzles are arranged on a pitch circle of a die of the volume reducing molding machine, and radially extend from a boss portion of a cutting member formed on the same axis as a screw of the volume reducing molding machine. A plurality of cutting blades, which are arranged at a fixed distance from the end face of the nozzle and have a steel wire as a main part, are attached to the tip end of the provided arm section, and the cutting blade rotates along the end face of the nozzle. A cutting device for volume reduction molding of waste plastic, wherein a cutting blade cuts a rod-like discharge material discharged from a nozzle opening of the nozzle into a predetermined length. 2. The mounting position of the cutting blade for cutting the rod-shaped discharge material according to claim 1, wherein the distance between the end face of the nozzle and the cutting blade is constant according to the protrusion length of the nozzle changed by the nozzle replacement. A plurality of cutting blade mounting holes are provided at different positions in the screw axis direction at the tip of the arm portion of the cutting member so that the cutting member can be changed to a predetermined position. apparatus.