JP2004275855A - Method and apparatus for classifying cullet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and an apparatus for classifying cullet capable of classifying even the cullet varying in thicknesses with good accuracy. <P>SOLUTION: In the method for classifying the cullet varying in colors and/or vitreous components by the transmittance of light, the desired cullet and the other cullet are separated by comparing the ratio of the gradients of two different regions in a transmittance curve or the ratio of the inverse number of the gradients. Since the shape of the transmittance curve does not change so much by the difference in the thicknesses of the glass, sorting can be efficiently performed even for the glass of different thicknesses. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method and apparatus for separating desired color and / or glassy cullet from mixed coloured and / or glassy cullet.
[0002]
[Prior art]
In the production of glass products such as glass bottles and glass tableware, glass pieces for recycling, that is, cullets, are used as a part of raw materials. For example, when producing brown bottles (such as beer bottles) with the most common soda-lime glass, brown cullet is used, most of which are brown cullet of soda-lime glass, but with a small amount of heat-resistant inside. Light brown cullet of glass is mixed. Light brown cullet made of heat-resistant glass was used in cooking equipment such as pots and tableware, but was mixed in during the recycling process. When heat-resistant glass cullet is mixed into the raw material of soda-lime glass products, most of the heat-resistant glass that enters the melting furnace exits the melting furnace without being melted. As a result, the yield is reduced. In addition, since the defective product is fed into the melting furnace again as a raw material, foreign substances are repeatedly mixed. In addition, before forming a product, the molten glass is cut with a shear (cutting blade) to make a gob (molten glass lump). However, cutting the heat-resistant glass that has been mixed will damage the shear, and the shape of the gob after that Is changed, and proper molding cannot be performed. As described above, when the heat-resistant glass cullet is mixed in the raw material, a large production loss is generated.
[0003]
For the above reasons, light brown heat-resistant glass cullet is separated from normal soda-lime glass brown cullet. As such a sorting method, for example, Japanese Patent Application Laid-Open No. H10-34088 discloses a method using an emission spectrum by laser light irradiation. As a sorting method using visible light, for example, Japanese Patent Application Laid-Open No. 2001-269629 discloses a method of sorting heat-resistant glass from a difference in transmittance at a predetermined wavelength (630 to 700 nm).
[0004]
[Problems to be solved by the invention]
The above-described method using the emission spectrum by laser light irradiation is not practical because it requires not only expensive and complicated equipment but also technical difficulties in increasing the separation accuracy. In addition, the method of separating heat-resistant glass from a difference in transmittance at a predetermined wavelength (630 to 700 nm) has a limitation in separation accuracy. In other words, in this method, the brown of the heat-resistant glass is considerably light brown compared to the brown of the soda-lime glass, and is classified according to the difference in the color depth. By the way, the light transmittance changes according to the color density and also changes according to the thickness of the glass. Thicker glass has a lower transmittance than thin glass. For example, in the range of 630 to 700 nm, the brown heat-resistant glass having a thickness of 15 mm and the brown soda-lime glass having a thickness of 1 mm have almost the same transmittance and cannot be separated. Generally, the heat-resistant glass cullet is thick (because it is used as a pan, tableware, etc.), and the soda-lime glass cullet is thin (because it is often used as a bottle), so the sorting accuracy is considerably poor. A large amount of thin soda-lime glass cullet is mixed with the separated heat-resistant glass cullet.
[0005]
An object of the present invention is to develop a method and an apparatus for separating cullets that can accurately separate cullets having different thicknesses.
[0006]
[Means for Solving the Problems]
The present invention provides a method for separating color and / or glassy cullet, which differs depending on the light transmittance, by comparing the ratio of the slopes of two different regions or the ratio of the reciprocal of the slope in the transmittance curve. A cullet separation method characterized by separating cullet from other cullet.
[0007]
As described above, simply measuring the transmittance at a certain wavelength (or a certain range of wavelengths) makes it impossible to accurately separate cullets having different thicknesses. The present invention is completely different from such a conventional technical idea. Glass has a specific transmittance curve depending on the color or glass quality, and the transmittance value changes at different thicknesses, but the shape of the curve does not change much while maintaining the characteristics. Therefore, if the two most characteristic areas of the curve are selected and the ratio of the slope (or the reciprocal of the slope) is expressed by a numerical value, the feature is amplified and the selection becomes easy. Since the shape of the transmittance curve does not change much depending on the thickness, it is possible to efficiently sort glass of any thickness.
[0008]
Specifically, the transmittances A, B, and C at arbitrary three different wavelengths a, b, and c are measured for each cullet, and (BC) / (bc) is calculated as (AB) / (a). -Find the value X divided by b) or the reciprocal of X. By comparing X or the reciprocal of X with an arbitrary threshold value, it is possible to determine whether or not the cullet is a desired cullet.
[0009]
This method includes a conveying unit, a light source that irradiates light to the cullet being conveyed by the conveying unit, a light receiving unit that receives light of any three different wavelengths a, b, and c among light transmitted through the cullet, The value obtained by dividing (BC) / (bc) by (AB) / (ab) from the light intensities A, B, and C of the wavelengths a, b, and c received by the light receiving means. This is realized by a cullet discriminating apparatus having control means for determining X or the reciprocal of X and comparing the reciprocal of X or X with an arbitrary threshold value to determine whether or not the cullet is a desired cullet. If the apparatus is provided with a separating means for separating a desired cullet from another cullet based on the determination of the control means, the cullet can be automatically separated according to its type. In the present invention, the light transmitted through the cullet includes the transmitted light included in the reflected light reflected from the cullet.
[0010]
In addition, the transmittances A, B, C, and D at four different wavelengths a, b, c, and d for each cullet were measured, and (CD) / (cd) was calculated as (AB) / ( a) calculating the value X or the reciprocal of X, and comparing the reciprocal of X or X with an arbitrary threshold to determine whether the cullet is the desired cullet or not; Can be.
[0011]
This method comprises a conveying means, a light source for irradiating light to the cullet being conveyed by the conveying means, and a light receiving means for receiving light of any four different wavelengths a, b, c and d among the light transmitted through the cullet. From the intensities A, B, C, and D of the wavelengths a, b, c, and d received by the light receiving means, (CD) / (cd) is calculated as (AB) / (a− b) the value of X or the reciprocal of X is obtained, and the reciprocal of X or X is compared with an arbitrary threshold to determine whether the cullet is a desired cullet or not. Implemented by the device. If the apparatus is provided with a separating means for separating a desired cullet from another cullet based on the determination of the control means, the cullet can be automatically separated according to its type.
[0012]
When determining the transmittance (light intensity) at the wavelengths a, b, c, or d, for example, if the wavelength a is 700 nm, it is difficult to accurately measure the transmittance at 700 nm. For example, the light intensity in the range of 700 nm ± 10 nm is measured, and the average is taken to be the transmittance A at 700 nm.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 is an explanatory diagram of a cullet sorting device according to an embodiment. This separation apparatus separates a brown (amber) cullet of soda-lime glass and a light brown cullet of heat-resistant glass. Reference numeral 1 denotes a hopper for supplying a fixed amount of cullet 3 in which brown cullet of soda-lime glass and light brown cullet of heat-resistant glass are mixed. Reference numeral 2 denotes a conveyor as a transporting means. Reference numeral 4 denotes a separation container for storing the separated cullet, reference numeral 5 denotes illumination for irradiating visible light, reference numeral 6 denotes a CCD camera serving as a light receiving unit, reference numeral 7 denotes a filter, reference numeral 8 denotes control means such as a sequencer, and reference numeral 9 denotes separation. It is a high-pressure air injection device as a means.
[0014]
A cullet 3 in which a brown cullet of soda-lime glass and a light brown cullet of heat-resistant glass are mixed is put into a hopper 1 and further supplied from the hopper 1 to a conveying means 2 (conveyor) in a fixed amount. The cullet 3 is conveyed on the conveying means 2 in the direction of the arrow (rightward in FIG. 1), and falls from the end of the conveying means 2 toward the portion 4 a of the separation container 4 which accommodates the brown cullet of soda-lime glass. The illumination 5 is provided so as to irradiate the falling cullet 3 with light, and three light receiving means 6 (CCD cameras) are provided at positions where the light passing through the falling cullet 3 is received. A filter 7 is provided before the filter 6. The filter 7a before the light receiving means 6a is mainly light having a wavelength of 690 to 710 nm, the filter 7b before the light receiving means 6b is light having a wavelength of 590 to 610 nm, and the filter 7c before the light receiving means 6c is light having a wavelength of 440 to 460 nm. Of light. That is, the light receiving means 6a receives light having a wavelength of 690 to 710 nm, the light receiving means 6b receives light having a wavelength of 590 to 610 nm, and the light receiving means 6c receives light having a wavelength of 440 to 460 nm, and outputs the intensity. The light receiving means 6a outputs light of a wavelength of 700 nm, the light receiving means 6b outputs light of a wavelength of 600 nm, and the light receiving means 6c outputs light intensity (a value proportional to transmittance) of a wavelength of 45 nm. I can say. If the wavelength a is 700 nm, the wavelength b is 600 nm, and the wavelength c is 450 nm, the light receiving unit 6a has a transmittance A of the wavelength a, the light receiving unit 6b has a transmittance B of the wavelength b, and the light receiving unit 6c has a transmittance C of the wavelength c. Is output.
[0015]
FIG. 2 shows a transmittance curve 11 of a brown soda-lime glass having a thickness of 1 mm and a transmittance curve 12 of a light brown heat-resistant glass having a thickness of 15 mm. FIG. 3 shows the approximate slope of the transmittance curve 11 of the brown soda-lime glass having a thickness of 1 mm and the transmittance curve 12 of the light brown heat-resistant glass having a thickness of 15 mm in a wavelength range of a to b (700 to 600 nm). The graph shows an approximate slope in a wavelength range of b to c (600 to 450 nm).
[0016]
As is clear from FIG. 2, the transmittance curves 11 and 12 show that the transmittance at each wavelength is very similar, and it can be said that it is difficult to measure the transmittance at a specific wavelength and discriminate between the two. However, as shown in FIG. 3, when the slopes of the transmittance curves 11 and 12 in the two regions of the wavelengths a to b and b to c are taken, the slopes of the transmittance curves 12 are almost the same in the two regions. However, the transmittance curve 11 is significantly different between the two regions.
[0017]
FIG. 4 shows wavelengths a to b (700 to 600 nm) at various thicknesses of light brown heat-resistant glass (shown as “heat-resistant glass” in FIG. 4) and brown soda-lime glass (shown as “normal glass” in FIG. 4). ), A curve 13 representing the slope of the transmittance curve in the region of wavelengths b to c (600 to 450 nm), and a curve 14 representing the slope of the transmittance curve in the region of wavelengths a to b (700 to 600 nm). The curve 15 represents the ratio of the slope of the transmittance curve in the region to the slope of the transmittance curve in the region of wavelengths b to c (600 to 450 nm). That is, assuming that the transmittance at the wavelength a (700 nm) is A, the transmittance at the wavelength b (600 nm) is B, and the transmittance at the wavelength c (450 nm) is C, the curve 13 is (AB) / (a−). b), curve 14 represents (BC) / (bc), and curve 15 represents {(BC) / (bc)} / {(AB) / (ab)}. ing. As is clear from the curve 15 in FIG. 4, by taking the ratio between the two regions, the difference in the characteristics of the transmittance curves between the light brown heat-resistant glass and the brown soda-lime glass can be amplified and clearly distinguished. For example, in the curve 15, the threshold value is set to 15, and if it is 15 or less, it can be clearly discriminated as heat-resistant glass, and if it exceeds 15, it is soda-lime glass.
[0018]
In FIG. 1, the control means 8 (sequencer) determines the transmittance A at a wavelength a (700 nm), the transmittance B at a wavelength b (600 nm), and the transmittance C at a wavelength c (450 nm) from each of the light receiving means 6a, 6b, 6c. Then, the ratio X of the slope of the transmittance curve in two regions of wavelengths a to b (700 to 600 nm) and wavelengths b to c (600 to 450 nm) is calculated. That is, X is represented by the following equation.
X = {(BC) / (bc)} / {(AB) / (ab)}
Next, if the calculated X is equal to or smaller than the threshold value 15, the control means 8 determines that the cullet is heat-resistant glass, and activates the classification means 9 (high-pressure air injection device) to blow high-pressure air onto the cullet, thereby To the portion 4b for accommodating the light brown cullet. If X is greater than the threshold 15, the control means 8 determines that the cullet is soda-lime glass and does not activate the sorting means, and the cullet is placed in the portion 4a containing the brown cullet of soda-lime glass. Fall.
[0019]
The separating means 9 (high-pressure air injection device) has a high-pressure air tank, a solenoid valve, and an injection nozzle, and the control means 8 controls opening and closing of the solenoid valve. When it is determined that the cullet is a glass cullet), the solenoid valve is opened and high-pressure air is injected from the nozzle to pressurize the falling cullet.
[0020]
The configuration of the entire transmittance measuring apparatus according to the present invention is not limited to that for directly measuring transmitted light as shown in FIG. 1, but is included in reflected light as shown in FIG. 6 (the reference numerals in FIG. 6 are the same as those in FIG. 1). The configuration using transmitted light or another configuration can be used. Further, the transporting unit 2, the light receiving unit 6, the filter 7, the control unit 8, the separating unit 9 and the like are not limited to the embodiment, and can be replaced with another device having the same function. In the embodiment, the transmittances at three points of the wavelength abc are measured to determine the ratio of the slopes of the transmittance curves of the two adjacent regions. The ratio of the inclination of the transmittance of the two regions may be obtained. FIG. 5 shows a transmittance curve 16 of green soda-lime glass as an example. The transmittance ABCD at four points of the wavelength abcd is measured, and the ratio X or the reciprocal of X of the slope of the transmittance curve in the two regions of the wavelengths ab and cd is calculated. X is represented by the following equation.
X = {(CD) / (cd)} / {(AB) / (ab)}
[0021]
In the above embodiment, the case where cullet of brown soda-lime glass and light brown heat-resistant glass are separated is exemplified. However, the present invention is not limited to the separation of these two types of cullet, and various kinds of cullets having different transmittance curves are used. Can be used for sorting cullet. It is also possible to simultaneously sort three or more cullets.
[0022]
【The invention's effect】
According to the present invention, accurate separation can be performed even when cullets having different thicknesses are mixed. In addition, since a simple arithmetic expression is used, it is possible to perform high-speed discrimination with a simple device.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram of a sorting apparatus according to an embodiment.
FIG. 2 is an explanatory diagram of a transmittance curve 11 of a brown soda-lime glass having a thickness of 1 mm and a transmittance curve 12 of a light brown heat-resistant glass having a thickness of 15 mm.
FIG. 3 shows a slope of a transmittance curve 11 of a brown soda lime glass having a thickness of 1 mm and a transmittance curve 12 of a light brown heat-resistant glass having a thickness of 15 mm in a region of wavelengths a to b (700 to 600 nm) and a wavelength b. It is explanatory drawing of the inclination in the area | region of -c (600-450 nm).
FIG. 4 is an explanatory diagram of the slope of the transmittance curve of the light brown heat-resistant glass and the brown soda lime glass in the wavelength ranges of ab and bc.
FIG. 5 is an explanatory diagram in the case of measuring transmittance ABCD at four points of wavelength abcd.
FIG. 6 is an explanatory diagram of an example of a sorting device in a case where transmitted light included in reflected light is used.
[Explanation of symbols]
REFERENCE SIGNS LIST 1 hopper 2 transport means 3 cullet 4 sorting container 5 illumination 6 light receiving means 7 filter 8 control means 9 sorting means

Claims (6)

In a method of separating cullet of different colors and / or vitreous according to light transmittance, a desired cullet and other cullet are compared with each other by comparing a ratio of a slope of two different regions or a ratio of a reciprocal of a slope in a transmittance curve. A method for separating cullet, comprising separating cullet from cullet In the method for separating cullet according to claim 1, the step of measuring the transmittances A, B, and C at three different wavelengths a, b, and c for each cullet, and (B−C) / (bc) (AB) / (ab) dividing the value X or the reciprocal of X, and comparing X or the reciprocal of X with an arbitrary threshold value to determine whether the cullet is a desired cullet Distinguishing cullet, comprising the step of determining 2. The method for separating cullet according to claim 1, wherein the transmittances A, B, C, and D of four different wavelengths a, b, c, and d are measured for each cullet, and (C−D) / (c−). d) dividing the value by (AB) / (ab) to obtain a reciprocal of X or X, and comparing the reciprocal of X or X with an arbitrary threshold value so that the cullet is a desired cullet. Distinguishing whether or not there is a cullet Conveying means, a light source for irradiating light to the cullet being conveyed by the conveying means, light receiving means for receiving light of any three different wavelengths a, b, and c out of light transmitted through the cullet; Of the value X or X obtained by dividing (BC) / (bc) by (AB) / (ab) from the light intensities A, B and C of the wavelengths a, b and c. A cullet discriminating apparatus comprising a control means for determining a reciprocal and comparing the reciprocal of X or X with an arbitrary threshold to determine whether or not the cullet is a desired cullet. Conveying means, a light source for irradiating light to the cullet being conveyed by the conveying means, light receiving means for receiving light of any four different wavelengths a, b, c, d among light transmitted through the cullet; light receiving means (CD) / (cd) is divided by (AB) / (ab) from the light intensities A, B, C, D of the wavelengths a, b, c, d received at And a control means for determining whether or not the cullet is a desired cullet by comparing the value X or the reciprocal of X and comparing the reciprocal of X or X with an arbitrary threshold value. Sorting device 6. The cullet separation apparatus according to claim 4, wherein the separation apparatus includes a separation unit that separates a desired cullet from another cullet based on the determination of the control unit.

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