JP3269216B2 - Microwave pyrolysis furnace - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to recovery of a metal core (metal body) such as a steering wheel for a vehicle coated with polyurethane or plastic, and more particularly to recovery of a metal body by pyrolyzing and discharging plastic. The present invention relates to a microwave pyrolysis furnace suitable for the present invention.

[0002]

2. Description of the Related Art Conventionally, defective plastic coatings such as a steering wheel for a vehicle generated in a production stage are swollen by cutting a knife in a plastic such as polyurethane as a coating material and immersing them in an organic solvent overnight. The plastic is scraped off with a knife, and finally the surface of the metal core is polished and finished with a wire brush to collect the aluminum or iron metal core. Such manual work severely limits the processing capacity of the stripping means. As alternative means, there are thermal decomposition means and high-frequency heating means.However, unless the ambient temperature is set to a considerably high temperature, the plastic does not thermally decompose in a short time and is exposed to an excessively high temperature. There is a possibility that aluminum may partially melt or iron may be thermally deformed.

Further, a microwave pyrolysis furnace has been proposed in which a plastic coating is heated by irradiating a microwave to thermally decompose the plastic, flow down a grid-like separator and discharge the same. Although this furnace has a simple discharge structure and has economic advantages, the temperature control becomes complicated when changing the ambient temperature between the time of pyrolysis and the time of discharge, because the pyrolyzed plastic is put into a low sticky state. There is fear.

[0004]

In the conventional plastic pyrolysis means, since the plastic is thermally decomposed and removed from the plastic coating while maintaining the ambient temperature at a considerably high temperature, the metal body is partially melted. And heat deformation. Further, in an apparatus for thermally decomposing a plastic coated on a metal body by irradiating a microwave, there is a problem that the atmosphere temperature control is complicated in order to make the state of stickiness easy to discharge.

An object of the present invention is to provide a microwave pyrolysis furnace capable of thermally decomposing plastic coated on a metal body while preventing thermal deformation of the metal body and easily discharging the plastic even in a highly tacky state. To provide.

[0006]

In order to achieve the above-mentioned object, a microwave pyrolysis furnace according to the present invention comprises a plastic coating comprising a metal body coated with polyurethane or a plastic containing polyurethane via an adhesive. A microwave oven that heats the plastic coating by irradiating microwaves to the cracking furnace and pyrolyzes the plastic and adhesive, and sends out the pyrolyzed plastic that is juxtaposed below the cracking furnace And at least a pair of discharge rollers.

[0007]

According to the present invention, the plastic itself absorbs the microwaves and emits heat when irradiated with the microwave, so that only the plastic is heated to a predetermined temperature and the metal body is not exposed to an unnecessarily high temperature atmosphere. . In addition, heating start and stop are instantaneously performed, and temperature control is easy. The plastic begins to decompose and melt by heating, and falls off the metal body.However, a pair of discharge rollers are installed at the bottom of the decomposition furnace and they rotate in opposite directions. , And is forcibly transmitted while being sandwiched between the discharge rollers, and the microwave is attenuated to a greater extent than between the pair of discharge rollers. Therefore, the plastic accumulated under the pair of discharge rollers does not undergo excessive thermal decomposition, and microwaves are not unnecessarily consumed.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to FIG. As shown in FIG. 1, a decomposition furnace 2 for accommodating a plastic coating 1 such as a vehicle steering wheel or the like in which a metal body is coated with polyurethane or a plastic containing polyurethane via an adhesive, and the decomposition furnace 2 is irradiated with microwaves. A microwave oscillator 3 for heating the plastic coating 1 to thermally decompose the plastic and the adhesive, and at least a pair of discharge rollers 5 provided at the lower part of the decomposition furnace 2 for feeding out the thermally decomposed plastic are provided. Configuration.

The decomposition furnace 2 is housed in an applicator 6,
The microwave oscillator 3 has a waveguide 7 on the upper part of the applicator 6.
Connected via At the bottom of the applicator 6, a carbon dioxide gas inlet 8 is provided, and at the top of the applicator 6, a gas outlet 14 for discharging generated gas is provided. A pair of discharge rollers 5 is rotatably disposed below the cracking furnace 2 via a skirt 9, and a falling object accumulation chamber 11 mounted on a guide rail 10 is detachably provided below the applicator 6. . A plurality of the plastic coatings 1 are stacked in a vertically extending manner through a shaft 12 and housed in a cracking furnace 2, and the lower end of the shaft 12 is connected to a motor (not shown) to be rotated.

As shown in FIGS. 1 to 3, the pair of discharge rollers 5 are formed in a cylindrical shape and are arranged side by side with the longitudinal direction being horizontal, and a plurality of protrusions 13 are provided at a predetermined pitch in the horizontal direction. It is connected at one end in the horizontal direction to a drive motor 15 provided outside the applicator 6 via a gear mechanism 16. On the other end in the horizontal direction, an opening / closing door for inspecting and maintaining the discharge roller 5 is provided. A pair of discharge rollers 5
Are arranged substantially in parallel with a gap such that the projections 13 do not come into contact with each other. One of the discharge rollers 5 rotates clockwise and the other discharge roller 5 rotates counterclockwise. A scraper 17 having a knife-shaped upper end protrudes between the protrusions 13. A suitable material for the discharge roller 5 is a material that does not absorb microwaves and has a heat resistance of 200 ° C. or higher, for example, paramagnetic 18Cr8Ni stainless steel. It is also important to set a gap so that microwaves do not penetrate between the pair of discharge rollers 5 or between the inner wall of the applicator 6 and the thermally decomposed plastic can be sufficiently discharged. Since the amount of microwave leakage is proportional to the ratio of the area of the gap to the bottom area of the entire cracking furnace, if the gap is made smaller, the influence of the leakage is almost eliminated.

Next, the operation of this embodiment will be described. Decomposition furnace 2
While rotating a plurality of plastic coverings (vehicle steering wheel) 1 accommodated in the motor by a motor (not shown), the microwave oscillator 3 controls and irradiates a microwave of about 2450 MHz by control means (not shown). Microwaves enter the interior of the applicator 6 through the waveguide 7 from the top center and are uniformly dispersed and absorbed by the plastic. At this time, the plastic coating 1 is rotated at a low speed to absorb uniform microwaves, and a carbon dioxide gas or an inert gas is circulated as a seal gas into the cracking furnace 2 at a rate of 30 liter / min. Atmosphere temperature of the cracking furnace 2 is 300
By controlling the temperature to about 500 ° C., the plastic falls in a ring shape in about 20 minutes, and adheres to the upper surfaces of the pair of discharge rollers 5. Since the discharge rollers 5 rotate in opposite directions to each other, plastic is caught between the discharge rollers 5, and even if the plastic has high adhesiveness, it passes through the gap between the projections 13 and forcibly flows downward. , Falling object accumulation room 11
Will be integrated. Although the microwaves enter the gap to a depth of about 50 mm, the microwaves do not penetrate to the falling object accumulation chamber 11 and the microwaves are not unnecessarily consumed. Problems such as gasification due to excessive wave irradiation can be prevented. Then, the falling object accumulation chamber 11 is removed from the applicator 6 and moves on the guide rail 10 to be easily carried out to the outside, so that the plastic can be discarded and incinerated.
Note that a water jacket 18 may be provided inside the discharge roller 5 to cool the discharge roller 5 by circulating bearing cooling water, and adjust the adhesiveness of the plastic by changing the temperature of the plastic. The metal body can be easily recovered by opening a part of the applicator.

FIG. 4 shows another embodiment of the present invention. The difference from the embodiment shown in FIG. 1 is that the thermally decomposed plastic is conveyed by a conveyor 19, and no projection is formed on a pair of discharge rollers 5 located below the plastic, and they are arranged side by side through a predetermined gap. Are rotating in opposite directions. Also, the falling object accumulation chamber 11 is detachably connected to the lower end of the applicator 6, and when the thermally decomposed plastic is accumulated, the falling object accumulation chamber 11 is detached from the applicator 6 and moved to the outside by the cart 18 with a lift. It is a configuration that can be done. With this configuration, the same operation and effect as those of the embodiment shown in FIG. 1 can be obtained.

[0013]

According to the present invention, the plastic coated on the metal body is thermally decomposed by microwaves, so that thermal deformation of the metal body is prevented, the apparatus can be implemented, and the thermally decomposed plastic is put into a pair. The discharge roller can be forcibly discharged by the rotation of the discharge roller, so that there is an effect that the processing capability of the plastic coating increases and the driving operation becomes easy.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing one embodiment of the present invention.

FIG. 2 is a cross-sectional view of FIG.

FIG. 3 is a side view showing the discharge roller of FIG. 1;

FIG. 4 is a sectional view showing another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Plastic coating 2 Decomposition furnace 3 Microwave oscillator 5 Discharge roller 6 Applicator 7 Waveguide 8 Carbon dioxide gas inlet 9 Skirt 10 Guide rail 11 Falling object accumulation chamber 12 Axis 13 Projection 14 Gas outlet 15 Drive motor 16 Gear mechanism 17 Scraper

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Toshiro Inomata 1, Yawata Kaigandori, Ichihara-shi, Chiba Chiba Shipbuilding Co., Ltd. Chiba Works (72) Inventor Yoshiaki Matsumoto 1, Yawata-kaigandori, Ichihara-shi, Chiba Mitsui Engineering Ship Inside the Chiba Works Co., Ltd. (72) Kazuo Sato 5-6-4 Tsukiji, Chuo-ku, Tokyo Mitsui Engineering & Shipbuilding Co., Ltd. (72) Inventor Toshikatsu Togawa 1 Ochiai Ogataai Ogataai Kasuga-cho, Aichi Prefecture Toyoda Gosei In-house (72) Inventor Masahiro Takimoto 1st Ochiai Nagahata, Kasuga-cho, Nishi-Kasugai-gun, Aichi Prefecture Inside Toyoda Gosei Co., Ltd. (56) References JP-A-6-256561 (JP, A) JP-A-56-87715 (JP, A) JP-A-54-56680 JP, A) JP flat 5-138799 (JP, A) (58 ) investigated the field (Int.Cl. ^7, DB name) B29B 17/00 - 17/02 C08J 11/00 - 11/28 B09B 3 / 00-5/00

Claims (1)

(57) [Claims] A decomposition furnace containing a plastic coating in which a metal body is coated with polyurethane or a plastic containing polyurethane via an adhesive, and the decomposition furnace is irradiated with microwaves to heat the plastic coating. A microwave oscillator for thermally decomposing the plastic and the adhesive, and at least one pair of discharge rollers arranged at a lower portion of the decomposition furnace and sending out the thermally decomposed plastic. Pyrolysis furnace.