JPH0740345A - Method for processing plastic as waste and device therefor - Google Patents

Abstract

PURPOSE:To effectively use a plastic as a fuel or a material to be regenerated by a method wherein a plastic is heated under vacuum atmosphere to be melted or evaporated, and this is cooled and solidified to be recovered in the atmosphere. CONSTITUTION:A gas in a container 11 is exhausted under vacuum atmosphere, and a remaining gas is dilute. Therefore, an existing amount of oxygen is not sufficient for ignition and combustion. If a plastic is heated above the ignition temperature of the plastic, the plastic does not ignite and burn but melts into a liquid phase. A part of the liquid plastic is evaporated into a gas phase. The liquid plastic is cooled and solidified under vacuum atmosphere. The evaporated gaseous substance from a part of the liquid plastic is cooled and solidified by a collecting device 10 provided in the path of vacuum exhaust pipes 16-19. The solidified substance is recovered in the atomosphere. In this manner, the plastic is effectively used as a fuel or a material to be regenerated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to disposal of plastics and processing of raw materials for recycling.

[0002]

2. Description of the Related Art Disposal of plastic is landfilled,
The wastes such as incineration are mainly taken, and some of them are used as fuel or provided as raw materials for regeneration, but since the original form is bulky, the above-mentioned treatment is taken after the volume reduction process. The conventional plastic volume reduction processing is electricity,
It has been carried out by heating gas, steam, etc., but these were all heat treatments in the atmosphere containing oxygen.

[0003]

In the conventional heating in the atmosphere, when the temperature exceeds a certain limit temperature, ignition and combustion occur,
Not only is it impossible to recover after volume reduction, but poisonous gas is generated, which causes pollution, so there was no risk of ignition or combustion, and it was necessary to perform heat treatment at a low temperature for safety reasons. For this reason, there has been a problem that it takes time to reduce the volume of a large amount of plastic and the efficiency is low.

According to the present invention, when heating plastic, there is no fear of ignition or combustion, and the temperature is raised to a temperature much higher than the ignition temperature of the plastic so that it is instantly melted or evaporated, The purpose is to significantly improve the effect of volume reduction.

[0005]

SUMMARY OF THE INVENTION The present invention provides a method and apparatus for recovering plastic by heating, melting or evaporating plastic in a container under a vacuum atmosphere and then cooling and solidifying the plastic. Inside the container in a vacuum atmosphere, the gas inside is removed and the residual gas is extremely dilute. Therefore, the amount of oxygen required for ignition and combustion does not exist, and even if the temperature exceeds the ignition temperature of plastics, ignition and combustion do not occur, it melts and becomes liquid, and part of it vaporizes to become gas. .

The liquefied plastic is cooled and solidified in a vacuum atmosphere, and the vaporized material partially evaporated from the liquid to become a gas is cooled and solidified by a collecting device provided in the middle of the vacuum exhaust pipe. Each solidified substance can be collected in the atmosphere and effectively used as a fuel or a raw material for regeneration. Further, since it can be heated at a high temperature, it can be processed efficiently in a short time.

The plastic is fed into a charging hopper located at the top of the feed chamber. The cutout valve provided between the charging hopper and the supply chamber is opened to load the plastic into the supply chamber, and the cutout valve is closed when the charging is completed. At this time, all the valves are closed so that the airtightness of each of the supply chamber, the melting chamber, and the cooling chamber is maintained.

Through a vacuum exhaust pipe connected to each chamber,
Air in each chamber is sucked out and heating of the melting chamber is started.
When the vacuum degree of each chamber and the temperature of the melting chamber reach a predetermined value, the injection valve between the supply chamber and the melting chamber is opened, and the plastic is fed from the supply chamber to the melting chamber. When the feeding of the plastic from the supply chamber is completed, the injection valve is closed.
Even during the opening / closing operation of the closing valve, each chamber is kept in a vacuum atmosphere.

The plastic immediately melts in the melting chamber and is dripped through a screen provided in the melting chamber.
It is stored at the bottom of the melting chamber. A part of the melted plastic is vaporized to become a gas, which is sucked through the vacuum exhaust pipe and is cooled, solidified and collected by a collector provided in the middle of the pipe path.

When a certain amount of the melted plastic liquid is stored in the bottom of the melting chamber, the sluice valve provided in the bottom of the melting chamber is opened, and the liquid drops and flows into the cooling chamber. A mold for solidifying into a desired shape is disposed in the cooling chamber, and the liquid is contained in the mold and is cooled and solidified by the cooling device. When the dropping of the liquid from the melting chamber is completed, the sluice valve is closed.

After being cooled and solidified in the cooling chamber, the extraction valve on the atmosphere side of the cooling chamber is opened and the mold is taken out into the atmosphere. After the removal is completed, a new mold is charged, the extraction valve is closed, and the cooling chamber is again in a vacuum atmosphere. Note that, while the extraction valve is open, the shutoff valve provided in the pipeline of the vacuum exhaust pipe connected to the cooling chamber is closed.

[0012]

EXAMPLES Examples will be described with reference to the drawings.
In FIG. 1, plastic as waste is conveyed and loaded into a charging hopper 12 provided on the upper portion of the apparatus by a belt conveyor (not shown) or the like. A cut-out valve 4 for shutting off the supply chamber 1 from the atmosphere and keeping it airtight is provided below the charging hopper 12, and the charged plastic is supported and closed by the cut-out valve 4. A pipe 16 for vacuum exhaust is connected to the supply chamber 1, and a shutoff valve 2 is provided between the supply chamber 1 and the vacuum exhaust device 15.
0 is provided.

At the lower part of the supply chamber 1, there is provided an injection valve 5 for maintaining the airtightness between the supply chamber 1 and the melting chamber 2 and for storing the plastic supplied to the supply chamber 1, which is connected to the injection valve 5. Then, the melting chamber 2 is arranged. A pipe 17 for vacuum exhaust is connected to the melting chamber 2, and a shutoff valve 21 is provided between the melt chamber 2 and the vacuum exhaust device 15.

The melting chamber 2 is provided with a heating device 8 for heating the inside of the melting chamber 2. A guide plate is provided inside the heating device 8 so that the plastic and the plastic and the liquid can be smoothly dropped or dropped when it becomes a liquid. 13 is built in. Melting chamber 2
The heating and melting process of the plastic is performed in the vacuum atmosphere.

The melting chamber 2 is provided with a screen 14 which supports molten plastic and allows the liquid after melting to pass through. The liquid that has passed through the screen 14 and dropped is fed to the melting chamber 2 and the cooling chamber 3. It is stored in the upper part of the sluice valve 6 that can be opened and closed to maintain the airtightness between them.

A pipe 18 for vacuum exhaust is connected to the cooling chamber 3 and a shutoff valve 22 is provided. In the cooling chamber 3,
A cooling device 9 is provided to solidify the liquid dropped from the melting chamber 2. The mold 11 is placed in the cooling chamber 3 to have a shape and dimensions that allow the liquid to be accommodated and solidified and then reused after recovery. The processed product solidified in the mold 11 is taken out by opening the extraction valve 7.

Reference numeral 10 is a collecting device, which is provided in the middle of the pipeline of the vacuum exhaust pipe. Since the melting chamber 2 and the cooling chamber 3 are kept in a vacuum atmosphere, a part of the liquid is evaporated and vaporized during vacuum evacuation and is sucked by the vacuum evacuation device 15. The evaporated substance is cooled and solidified by the collector 10.

Although the heating device 8 for the melting chamber 2 is provided inside the melting chamber 2 in FIG. 1, it may be arranged outside the melting chamber 2 to heat the inside. It is also possible to provide a heating device in the supply chamber 1 and dry the plastic to be melt-processed in advance.

[0019]

Since the present invention is constructed as described above, it has the following effects.

Since the plastic is heated in a container under a vacuum atmosphere, there is no fear of ignition and combustion, and since it can be heated to a temperature higher than the ignition temperature, it can be melted and reduced in volume in a short time.

Since there is no reaction with other gas during the volume reduction process, the substance solidified and recovered can be effectively utilized as a raw material for regeneration.

The apparatus is composed of a supply chamber, a melting chamber, and a cooling chamber, each of which is independently vacuum-tightly maintained, so that it is a device capable of continuous processing.

[Brief description of drawings]

FIG. 1 is a diagram showing a section of a part of an apparatus for melting and evaporating plastic in a vacuum atmosphere, cooling and solidifying the plastic, and collecting the plastic in the atmosphere.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Supply chamber 2 Melting chamber 3 Cooling chamber 4 Cut-off valve 5 Input valve 6 Gate valve 7 Extraction valve 8 Heating device 9 Cooling device 10 Collection device 11 Mold 12 Charging hopper 13 Guide plate 14 Screen 15 Vacuum exhaust device 16, 17, 18, 19 Vacuum exhaust pipe 20, 21, 22 Shut-off valve

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location B09B 3/00 C08J 11/12 7310-4F // B29K 105: 26

Claims (4)

[Claims] 1. Heating plastic in a vacuum atmosphere,
A method for treating plastics as waste, which comprises melting or evaporating and then cooling and solidifying the melted or evaporated substance and collecting it in the atmosphere. 2. A cut-out valve which is composed of a supply chamber (1), a melting chamber (2) and a cooling chamber (3), and which can be opened / closed on the atmosphere side of the supply chamber (1) to keep airtightness with the atmosphere. (4) is a supply valve (5) between the supply chamber (1) and the melting chamber (2) and between the melting chamber (2) and the cooling chamber (3), which can be opened and closed to maintain airtightness of each chamber, and A sluice valve (6) is provided on the atmosphere side of the cooling chamber (3) with an openable and closable extraction valve (7) for maintaining airtightness with the atmosphere, and a supply chamber (1), a melting chamber (2) and a cooling chamber. Each chamber of (3) is configured so as to be independently maintained in a vacuum atmosphere, and a heating device (8) is provided in the melting chamber (2) and a cooling chamber (3) is provided.
Equipment for processing plastics as waste, equipped with a cooling device (9). 3. The processing apparatus according to claim 2, wherein a trapping device (10) for cooling and solidifying the vaporized substance in the exhaust gas is provided in the pipeline of the vacuum exhaust pipe (19). 4. The processing apparatus according to claim 2, wherein when the melt is cooled and solidified in the cooling chamber (3), the mold (11) is arranged so as to solidify into a desired size and shape.