JPH08300354A - Plastic sorting equipment - Google Patents

Abstract

(57) [Summary] [Purpose] To provide a plastic sorting device capable of quickly and highly accurately sorting waste plastic crushed material. [Structure] Conveying system 1 for moving a plurality of crushed plastic pieces, and light source 6 for irradiating plastic 7 with infrared light 5
A detection unit 2 comprising a measurement chamber 11 provided with a light receiver 10 for detecting transmitted light or reflected light 9 from a plastic piece.
In the plastic sorting device, a data processing unit 3 that analyzes the data obtained from the detection unit 2 and a sorting unit 4 that sorts the plastic pieces into types based on the signal from the data processing unit 3, The detection unit and the data processing unit that analyze the structure of the plastic are made sufficiently sensitive using Fourier transform infrared spectroscopy, and the type determination is performed quickly and with high accuracy.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sorting device for recycling plastics, and more particularly to a device for sorting waste plastics discharged from large wastes such as home electric appliances.

In recent years, various kinds of plastics have been used in large quantities in various fields. However, when these plastics are turned into waste, the current landfill treatment causes shortage of landfills and serious environmental problems. Therefore, it has become a particularly important issue recently to sort and recycle plastic scraps according to their types. Therefore, in order to promote the recycling and energy recovery of plastics generated from wastes, it is urgently necessary to develop plastics recovery technology and establish recycling system.

[0003]

2. Description of the Related Art When separating plastics, there are a method of separating a major part before crushing and a method of separating each plastic type after crushing. However, the latter method is commonly used to increase the reuse of mixed waste plastics.

At present, as a concrete method for separating each kind and component after pulverization, the polyolefin (PE, P) is utilized by utilizing the principle of cyclone and the difference in specific gravity of plastics.
P), vinyl chloride (PVC), other (ABS, etc.) 3
There is a plastic specific gravity sorting method that sorts and collects types.
In this sort of sorting apparatus, if the difference in specific gravity of the materials is about 0.5, the separation is performed well. However, in the case of the material with the small difference in specific gravity, there is a large error and there is a problem that the physical properties of the plastic cannot be sufficiently grasped. .

There is also a technique of using X-rays for separating a specific resin, but only a small amount of a different type of resin is mixed,
Since the physical properties may decrease, it was necessary to develop a technique for separating the resin into individual types. As a countermeasure against this, it is considered that a highly practical sorting device can be developed if the analysis technique using infrared rays can be applied to the type discrimination, and some results of the examination have already been reported.

In the case of analysis by infrared spectroscopy, a part of the sample is ground and placed on KBr (potassium bromide) that does not absorb infrared light, mixed, or the ground sample is fixed on a reflecting plate. However, there is a problem in that it takes a long time to pretreat the sample, and it is not practical to determine the type of plastic with an online device.

Further, a method of determining the type of plastic by the differential spectrum of near infrared rays is disclosed in Japanese Patent Laid-Open No. 6-308022. However, since this technique uses near-infrared rays and measures by a transmitted light method, it becomes impossible to measure those that cannot obtain transmitted light. Therefore, there was a problem that the sample had to be thin. Furthermore, in practical application, the separation speed, processing speed, applicable range, etc. were not sufficient.

[0008]

DISCLOSURE OF THE INVENTION The present invention provides a plastic sorting apparatus which solves the problems and inconveniences of the above-mentioned various conventional techniques and enables quick and highly accurate identification of plastic materials. Is an issue.

[0009]

In order to solve the above problems, in the present invention, a conveying system for moving a plurality of crushed plastic pieces, a light source for irradiating the plastic pieces with infrared rays, and a transmitted light from the plastic pieces or A detection unit consisting of a measurement chamber equipped with a light receiver for detecting reflected light, a data processing unit for analyzing the data obtained from the detection unit, and a plastic piece classified by type based on the signal from the data processing unit. In a plastic separation device composed of a separation mechanism part, a detection part that irradiates infrared light that does not contact the sample and can sufficiently grasp the physical properties of the plastic, and receives the reflected light to analyze the structure of the plastic In the data processing section, Fourier transform infrared spectroscopy is used to make it sufficiently sensitive to compensate for the point where sensitivity tends to be insufficient in infrared light analysis. In we decided to perform a type determination. Further, in order to improve the efficiency of collecting infrared rays, the inner surface of the detection unit measurement chamber was made into a spherical mirror surface, and a plurality of infrared light sources and light receivers were attached to the detection unit measurement chamber to improve the sensitivity.

[0010]

As described above, in the present invention, the reflected light from the sample is measured by Fourier transform infrared spectroscopy, so that the reflected light in the entire wavelength range can be measured at the same time, and the integration process can be repeated, resulting in rapid and high-speed operation. The type determination can be performed with accuracy. Moreover, since the reflected light can be efficiently collected by the light receiver, the sensitivity to the reflected light is improved and the material identification is facilitated.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a diagram showing the system configuration of an embodiment of the plastic sorting apparatus of the present invention. In the figure, 1 is a transport unit,
Reference numeral 2 is a detection unit, 3 is a data processing unit, and 4 is a sorting unit. The plastic 7 crushed to a size of 10 cm or less by the crushing device is moved by the belt conveyor 1 a of the conveying unit 1 and is conveyed to the detecting unit 2. Infrared light is irradiated here, and the infrared light reflected from the sample is analyzed by the data processing unit 3 to identify the type of plastic and then sorted by the sorting unit 4.

FIG. 2 is a diagram showing the detection unit 2 and the data processing unit 3 in the plastic sorting apparatus according to the present invention, and is a diagram for explaining the outline of Fourier transform infrared spectroscopy.

The detecting section 2 is a light source 6 which comprises a tungsten lamp 6a for generating infrared light 5 and a movable mirror 6b.
And a light receiver 10 that detects transmitted light 8 or reflected light 9 from the measurement chamber 11 and the plastic 7 that is the sample. The data processing unit 3 includes the transmitted light 8 detected by the light receiver 10.
Alternatively, the reflected light 9 is Fourier-transformed to obtain an infrared absorption spectrum 12
Ask for.

The infrared light 5 for irradiating the sample can be switched to an infrared light 8a passing through a transmission path or an infrared light 9a passing through a reflection path by a mirror. Here, the infrared light 9a irradiated on the sample is focused by the Cassegrain lens 14, and the reflected light 9 enters the light receiver 10.

When Fourier transform infrared spectroscopy is used for the detector 2 and the data processor 3, infrared light in the entire wavelength range can be radiated at one time, and reflected light can be measured at the same time. In addition, since the sample having weak reflected light can be subjected to integration processing (processing to increase the number of infrared light irradiations), there is an advantage that the measurement can be performed with higher sensitivity than the conventional infrared spectroscopy.

FIG. 3A shows the measurement by transmission of Fourier transform infrared spectroscopy, and FIG. 3B shows the measurement by reflection.
Figure 4 shows the infrared absorption spectrum of plastic,
(A) shows the result by transmission and (b) shows the result by reflection.

As shown in FIG. 3, when the surface of plastic is irradiated with infrared light 5 of 2,500 to 16,000 nm, for example, the case of transmission and the case of reflection are shown in FIG.
A spectrum as shown in (a) and FIG. 4 (b) is obtained. In the transmission method, when the plate thickness of the plastic is large, the infrared light 5 is not transmitted, and therefore, the infrared absorption spectrum 12 (a) does not have a unique peak for determining an organic substance. However, it can be seen that many peaks are obtained in the infrared absorption spectrum 12 (b) measured by the reflection method. As already known, the spectrum of this reflected light shows the characteristics of organic substances, and FIG. 4 shows polypropylene (PP).

In the present invention, this reflection method is utilized to identify the plastic material. In the example described above, the case where the surface of the sample is flat has been described, but many crushed actual samples to be separated have a complicated shape with uneven surfaces. Further, in such a sample, it is difficult to collect the reflected light in the predetermined light receiver 10. Therefore, there is a problem that sufficient reflected light cannot be obtained and a good infrared absorption spectrum cannot be obtained. Therefore, in the embodiment of the present invention, the measuring chamber 11 as shown in FIG. 5 is used.

5 and 6 show the measuring chamber 11 used in the embodiment of the present invention. The sample 7 is irradiated with infrared light 5 from the light source 6 of the detection unit 2, and the reflected light 9 is guided to the light receiver 10 while being reflected by the inner surface of the mirror-finished spherical measurement chamber 11.
The signal from the light receiver 10 is data processed by Fourier transform to obtain an infrared absorption spectrum 12 as shown in FIG. The infrared absorption spectrum 12 recognizes the absorption wavelength peculiar to the plastic and determines the material of the plastic.
If the sensitivity is insufficient in the above embodiment, it is apparent that the sensitivity is improved by mounting a plurality of light sources 6 and light receivers 10 as shown in FIG. Also, K
The sensitivity is improved even if the infrared light is guided to an arbitrary position by using the Br-coated optical conduit 13 and the reflected light 9 is detected at the arbitrary position.

[0020]

As described above, according to the present invention, since the material of an organic substance such as plastic can be identified in a non-contact manner, the material of the industrial waste plastic crushed piece flowing on the belt conveyor can be identified and the plastic material can be identified. It will be possible to separate and facilitate recycling and promote reuse.

[Brief description of drawings]

FIG. 1 is a diagram illustrating a system configuration of a plastic sorting apparatus according to the present invention.

FIG. 2 is a diagram showing an outline of Fourier transform infrared spectroscopy, showing a detection unit and a data processing unit in the plastic sorting apparatus of the present invention.

FIG. 3 is a diagram illustrating a transmission method and a reflection method of Fourier transform infrared spectroscopy.

FIG. 4 is a diagram showing a comparison of infrared absorption spectra of plastics obtained by a transmission method and a reflection method using Fourier transform infrared spectroscopy.

FIG. 5 is a diagram showing a detection unit measurement chamber and a data processing unit according to the embodiment of the present invention.

FIG. 6 is a diagram showing a configuration of a measurement chamber with improved detection sensitivity for material discrimination in the embodiment of the present invention.

[Explanation of symbols]

1 ... conveying unit, 1a ... belt conveyor, 2 ... detecting unit,
3 ... Data processing unit, 4 ... Sorting unit, 5 ... Infrared light, 6
... light source, 6a ... tungsten lamp, 6b ... movable mirror, 7 ... sample, 8 ... transmitted light, 8a ... infrared light passing through transmission path, 9 ... reflected light, 9a ... infrared light passing through reflection path, 10 ... light receiver, 11 ... measurement room, 12 ... infrared absorption spectrum, 13 ... optical conduit, 14 ... Cassegrain lens.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toshiba Shiji 3681 Hayano, Mobara-shi, Chiba Hitachi Device Engineering Co., Ltd. In-house (72) Fumio Takeda Inventor, Fumio Takeda 502 Jinmachi, Tsuchiura, Ibaraki Prefecture

Claims (5)

[Claims] 1. A detection system comprising a conveying system for moving a plurality of crushed plastic pieces, a light source for irradiating the plastic pieces with infrared rays, and a photodetector for detecting transmitted light or reflected light from the plastic pieces. In the plastic sorting device, a plastic processing device configured to analyze the data obtained from the detection unit, a data processing unit that analyzes the data obtained from the detection unit, and a sorting mechanism unit that sorts the plastic pieces by type based on the signal from the data processing unit. A plastic sorting device characterized in that a type determination is performed using Fourier transform infrared spectroscopy in a detection unit and a data processing unit that perform analysis. 2. The plastic separation according to claim 1, wherein the surface of the plastic piece is irradiated with infrared light having a wavelength of 700 nm to 1 mm, and the type of plastic is discriminated from the wavelength characteristics of the reflected light. apparatus. 3. A detection section having a measurement chamber provided with a light source and a light receiver for inputting reflected light from a plastic surface generated by irradiation of infrared rays from the light source, wherein the inner surface of the measurement chamber has a spherical shape. The plastic sorting apparatus according to claim 1, wherein the inner surface is a mirror surface. 4. The plastic sorting apparatus according to claim 1, wherein a plurality of light sources and a plurality of light receivers are arranged in the detection section measuring chamber. 5. The light source and the light receiver are provided with optical conduits that do not absorb infrared rays in order to guide the infrared light to an arbitrary position and receive the reflected light at an arbitrary position. Plastic sorting equipment.