JP4847800B2 - Waste plastic high density volume reduction molding machine and its exhaust method - Google Patents

Description

  TECHNICAL FIELD The present invention relates to a waste plastic high-density volume reduction molding machine for producing pellets by compressing and kneading waste plastic and an exhaust method thereof.

  In equipment that recycles waste plastic discharged from local governments by the Containers and Packaging Recycling Law as raw materials for coke, the waste plastic becomes a fluff with components and shapes suitable for pelletization by rough crushing, sorting, and secondary crushing. The volume is reduced to produce pellets. The exhaust gas generated in the volume reduction molding machine is extracted using a suction fan or a vacuum pump and sent to a dust collector.

  FIG. 3 is a schematic view showing an outline of a conventional waste plastic high-density volume reduction molding machine.

  The fluff supplied in the cylinder 2 in which the screw 1 rotating inside is disposed is melted and kneaded by heating by the heater and the frictional heat of the fluff while moving by the rotation of the screw 1 and is pushed out from the die 3. The cylinder 2 is provided with vents 5a, 5b and 5c, and water vapor and volatile matter generated in the cylinder 2 are extracted from the vents 5a, 5b and 5c. The extruded kneaded product is cut into pellets P by being cut by the rotary blade 6.

In the high-density volume reduction molding machine, the temperature is raised to 180 to 220 ° C. by heating with the heater and the frictional heat of the fluff, and the specific gravity of the pellets is increased to a high density of about 0.8 to 0.9. In such high-density volume reduction molding, volume reduction waste does not occur, so that handling properties are improved, and it is possible to improve coke production and coke quality.
Japanese Patent Laid-Open No. 6-293021

  In a high-density volume-reduction molding machine, if gas such as air entrained by the fluff, water vapor generated by evaporation of attached water, and volatile matter generated from the melt is not extracted during the volume reduction process, the gas will enter the pellets. It remains, expands, and the cavity becomes larger and the specific gravity decreases. In particular, since the moisture accompanying the fluff varies from 5 to 20% by mass, in order to stably form a high moisture fluff, it is necessary to extract the moisture sufficiently.

  On the other hand, as shown in FIG. 3, the conventional high-density volume reduction molding machine is a large apparatus for removing gases such as water vapor and volatile matter from the three vents.

  Further, the metal foreign matter mixed in the fluff promotes the progress of wear of the screw, and there is a problem that the maintenance cost becomes large.

  The problem to be solved by the present invention is to efficiently remove and discharge the moisture accompanying the fluff and the gas generated in the process of volume reduction, and efficiently suck the gas inside the melt, thereby An object of the present invention is to provide a waste plastic high-density volume reduction molding machine capable of improving the specific gravity of pellets with a small apparatus and an exhaust method thereof.

  Another object is to provide a waste plastic high-density volume reduction molding machine capable of removing metallic foreign matters mixed in the fluff before charging, and an exhaust method thereof.

The waste plastic high density volume reduction molding machine of the present invention is charged in a waste plastic high density volume reduction molding machine that compresses and melts the introduced fluff while moving it with a rotating screw, and extrudes the melt to produce pellets. A drying device for drying the fluff in advance, a first vent disposed in a region where a part of the introduced fluff begins to melt, a second vent disposed in a region where the melting of the fluff has progressed, A vacuum pump that sucks the gas discharged from the second vent , and the drying device is an air current conveying type drying device that dries the fluff while flowing air with warm air. It has a discharge port for discharging a heavy object separated from the fluff during conveyance .

In addition, the exhaust method of the waste plastic high-density volume reduction molding machine of the present invention is a waste plastic high-density volume reduction molding in which the fluff is compressed and melted while being moved with a rotating screw, and the melt is extruded to produce pellets. In the exhaust method of the machine, a drying step of drying the fluff to be introduced in advance, and then exhausting the water vapor evaporated from the fluff from a first vent disposed in a region where a part of the introduced fluff begins to melt. 1 an exhaust step, and then look including a second evacuation step of sucking with the vacuum pump volatiles melt from the second vent melting of the fluff are disposed in the traveling regions, the drying step, with warm air The drying process is carried out by an air current conveying type drying apparatus that dries the fluff while air current is conveyed, and this drying step includes a step of discharging a heavy material separated from the fluff during the air current conveyance .

  In the present invention, it is preferable that the fluff to be added is dried until the moisture accompanying the fluff becomes 10% by mass or less in the prior drying step.

  In the present invention, the exhaust from the first vent does not need to be sucked with a vacuum pump and can be opened to the atmosphere. The exhaust once released to the atmosphere is preferably sucked by a blower and sent to a dust collector. Of course, the first vent and the blower may be connected by piping without releasing the first vent to the atmosphere, and the exhaust from the first vent may be sent to the dust collector.

  According to the present invention, since the fluff to be added is dried in advance, even if there is a lot of moisture accompanying the fluff, stable high-density pellets can be obtained without adding a vent or a vacuum pump or increasing the size. Obtainable. Further, since the exhaust can be simplified in two stages, the apparatus can be reduced in size.

In addition, pre-drying of the fluff is carried out with an air-conveying drying device that dries the fluff with warm air while air-conveying, and the heavy material separated from the fluff is discharged during air-conveyance, so it is mixed in the fluff The metal foreign matter can be removed before charging, and maintenance costs such as screw replacement costs can be reduced.

  FIG. 1 is a schematic view of a waste plastic high-density volume reduction molding machine according to the present invention, and FIG. 2 is a view showing a suction line of a second vent.

  The fluff is dried in advance by a drying device 7 and then charged into a cylinder 2 in which a screw 1 that rotates inside is disposed. The introduced fluff is melted and kneaded by the heating by the heater and the frictional heat of the fluff while being moved by the rotation of the screw 1 and pushed out from the die 3. The extruded kneaded product is cut into pellets P by being cut by the rotary blade 6.

  Thus, in the present invention, the fluff is dried by the drying device 7 before being put into the cylinder 2. That is, since the moisture accompanying the fluff obtained from the waste plastic varies from 5 to 20% by mass, it is dried by the drying device 7 so that the moisture becomes 10% by mass or less. The drying temperature is generally about 60 to 80 ° C.

  In FIG. 1, as the drying device 7, an air current conveying type drying device that dries while blowing the fluff with warm air is used. Then, a heavy object such as a metal foreign object is separated from the fluff during the air flow conveyance, and the separated heavy object is discharged from the lower discharge port 7a.

  In the present invention, the gas generated in the cylinder 2 is exhausted in two stages. First, in the first stage, water vapor generated by the evaporation of water accompanying the fluff is discharged from the first vent 4 disposed in a region where a part of the fluff begins to melt. The first vent 4 is open to the atmosphere, and the exhaust is sent to a dust collector.

  Next, in the second stage, exhaust gas is sucked by a vacuum pump from the second vent 5 disposed in the region where the melting of the fluff has further progressed, and the gas existing inside the melt is positively sucked. Perform deaeration to improve specific gravity. As shown in FIG. 2, the exhaust from the second vent 5 is sucked by the vacuum pump 9 through the trap 8.

[Example]
The fluff was dried in advance by the drying device 7 shown in FIG. 1 so that the water content was 10% by mass or less, and then the fluff was introduced into the cylinder 2 at 4.2 t / h and exhausted in two stages. The first vent 4 was evacuated by opening to the atmosphere, and the second vent 5 was sucked with a vacuum pump suction pressure of 100 Torr. The melting temperature was 180 to 220 ° C., and the specific gravity of the pellets was stable at 0.9.

[Comparative example]
The fluff was not pre-dried by the drying apparatus, and the other pellets were produced under the conditions of the above example. Since the resin temperature of the first vent part does not rise due to the influence of moisture and the waste plastic does not melt, fluff is scattered in the vent line, causing the line to be blocked, and long-term operation becomes impossible.

  As described above, high-density pellets could be stably produced by previously drying the fluff to be introduced according to the present invention. In addition, scattering of fluff was suppressed and stable operation was possible.

It is the schematic of the waste plastics high-density volume reduction molding machine of this invention. It is a figure which shows the suction line of a 2nd vent. It is the schematic of the conventional waste plastics high density volume reduction molding machine.

Explanation of symbols

1 screw 2 cylinder 3 dice
4 First vent 5 Second vent
6 Rotary blade 7 Drying device 7a Discharge port 8 Trap 9 Vacuum pump P Pellet

Claims (2)

In a waste plastic high-density volume reduction molding machine that compresses and melts the introduced fluff while moving it with a rotating screw and extrudes the melt to produce pellets, a drying device for drying the fluff to be fed in advance, and The 1st vent arrange | positioned in the area | region where a part of fluff begins to melt | dissolve, the 2nd vent arrange | positioned in the area | region where melting | fusing of the fluff advanced, and the vacuum pump which attracts | sucks the gas discharged | emitted from this 2nd vent The drying device is an air flow drying device that dries the fluff with hot air while air flowing, and the air flow drying device discharges a heavy material separated from the fluff during the air flow conveyance. Waste plastic high-density volume-reduction molding machine with a discharge port . In the exhaust method of a waste plastic high-density volume molding machine that compresses and melts the introduced fluff while moving with a rotating screw and extrudes the melt to produce pellets,
A drying process to dry the fluff to be input in advance;
Thereafter, a first exhaust process for exhausting water vapor evaporated from the fluff from a first vent disposed in a region where a part of the introduced fluff begins to melt,
Then look including a second evacuation step of sucking with the vacuum pump volatiles melt from the second vent melting of the fluff are disposed in the traveling regions,
Waste plastic including a step of performing the drying step with an air-flow conveying type drying device that dries the fluff while flowing the air with warm air, and the drying step includes discharging a heavy material separated from the fluff during the air-flow conveyance. Exhaust method of high density volume reduction molding machine.

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