JP2002357472A - X-ray liquid level inspection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make accurately determinable the height of charged liquid in an X-ray liquid level inspection device. SOLUTION: In this X-ray liquid level inspection device, two lines of X-ray detectors 3 arranged linearly are formed, and their surfaces are covered by two kinds of layers different in X-ray wavelength selectivity. The X-ray liquid level inspection device is provided with a determining means 25, which determines the liquid level inside the container by judging whether a detected object detected at the height of the two lines of X-ray detection elements arranged at the same height is a low atomic number substance or a high atomic number substance on the basis of a differential signal of detection signals from the two lines to X-ray detection elements arranged at the same height, and a display means displaying this determination result.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an X-ray detector for accurately determining the amount of liquid in a container based on a detection signal of transmitted X-rays.
The present invention relates to a linear fluid volume inspection device.

[0002]

2. Description of the Related Art An X-ray liquid amount inspection apparatus irradiates a sealed container conveyed on a belt conveyor with X-rays, detects the transmitted dose with a plurality of X-ray detectors, and detects the amount of transmitted light in the sealed container. It detects the height of the liquid level. When the height of the liquid surface reaches a predetermined height, the sealed container is allowed to pass as it is. I was

[Problems to be solved by the invention]

However, in the conventional apparatus, the liquid level is determined based on the transmitted dose of X-rays. Therefore, when the lid portion and the seam portion of the container have an X-ray transmission thickness and the X-ray signal is weakened. However, there is a problem that the liquid is erroneously determined to be a liquid.

First, as shown in FIG. 7 (b), when the amount of liquid is small and the space with the lid is large, the uppermost sensor used for judging the amount of liquid passes through the lid passing through the lid of the container.
If the height is set lower than the incident height of the line, erroneous determination can be prevented. However, when the amount of liquid is large as shown in FIG. 7C, the space between the lid and the lid is narrow, so that the X-ray incident angle becomes small, and the lid cannot be discriminated from the liquid, resulting in an erroneous determination. As a countermeasure, there is a method of enlarging the container to increase the head space. However, in this case, there has been a problem that the manufacturing cost is increased.

Further, since the seam portion also has a large X-ray absorption, it may be erroneously determined that the seam portion is a liquid even without the liquid. As a countermeasure, focusing on the fact that the width of the seam is narrower than the outer shape width of the product, a method of measuring multiple times and averaging to identify the accurate liquid level was used, but it took time to make a determination. And hindered speeding up.

An object of the present invention is to judge whether the atomic number of a detected part is low or high based on the radiation quality, not the dose of transmitted X-rays, and to judge exactly to which level the liquid has been injected. An object of the present invention is to provide an X-ray irradiator capable of performing the above-described operations.

[0007]

To achieve the above object, the present invention provides an X-ray source for irradiating X-rays in a horizontal direction, and a plurality of X-ray sources arranged in opposition to the X-ray source and extending in a vertical direction. An X-ray detector in which X-ray detection elements are linearly arranged;
An X-ray liquid amount inspection apparatus comprising: a container transporting device that moves so as to pass between a radiation source and the X-ray detector;
The linearly arranged X-ray detectors are composed of two rows, and the two rows are coated with two types of layers having different X-ray wavelength selectivities, and the two rows of X-ray detectors having the same height are detected. Determine whether the object to be detected at the height is a low atomic number substance or a high atomic number substance based on the difference signal of the detection signal from the element,
It is characterized in that it comprises a determining means for determining the amount of liquid in the container, and a display means for displaying the result of the determination.

[0008] An X-ray source for irradiating X-rays in the horizontal direction, a two-dimensional X-ray detector comprising an X-ray detecting element positioned opposite to the X-ray source and arranged two-dimensionally, and a container, An X-ray liquid amount inspection apparatus comprising: a container transporting device for moving the X-ray source so as to pass between the X-ray source and the X-ray detector;
Two types of layers having different wavelength selectivities are alternately coated on the front surface of the X-ray detection elements arranged in a three-dimensional manner, and based on the difference signal of the detection signals from the pair of adjacent X-ray detection elements. A determination means for determining whether the object to be detected at each detection position is a low atomic number substance or a high atomic number substance, and determining whether a foreign substance has entered the container based on each determination, A display means for displaying a result of the determination is provided.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a first embodiment of the present invention will be described in detail with reference to the drawings. However, FIG. 1 and FIG.
This figure shows a case in which two linearly arranged detectors are arranged in two rows in the vertical direction. First, FIG. 1 is a configuration diagram of the present embodiment. In FIG. 1, reference numeral 1 denotes X for generating X-rays.
X-ray source 2, X-ray flux generated by X-ray source 1, X-ray detectors 3A and 3B detect X-rays transmitted through the container, 4 is a container for inspecting the liquid volume by this apparatus, and 5 is a container 4. A container transport device for transporting, 6 and 7 are a projector and a light receiver for detecting whether the container 4 has been carried into the container transport device 5, and 8 is an X-ray detector 3A.
And a signal processing device for processing the signals obtained in 3B, 9
Is a material identification device for identifying the material of the object at each height based on the signal processed by the signal processing device, and 10 is the height of the liquid level in the container 4 based on the material identified by the material identification device 9. A reference numeral 11 denotes a control unit for controlling the entire apparatus, and 12 denotes a television monitor for displaying a detected signal, a determination result, and the like.

FIG. 2 is a block diagram of the present invention. In FIG. 2, 13 is a filter for selecting the wavelength of X-rays, 14 is an array-shaped X-ray detector that detects X-rays and converts them into electric signals, 15 is an amplifier that amplifies electric signals, and 16
A and 16B are multiplexers for switching signals from the amplifiers 15-1 to 15-N, 17 is an A / D converter for converting an analog signal into a digital signal, and 18 is a correction circuit for performing offset correction and sensitivity correction , 19 is an interface for converting the data of each detected pixel value to be input to the storage device 20, and 20 is the value of each detected pixel and the identification material name (the material having a high atomic number) identified by the material identification device 24. Or a material having a low atomic number), and 21 stores an output signal of the memory device 20, for example, a color scheme such as blue for a high atomic number substance and orange for a low atomic number substance. Look-up table (LUT) for creating a comparison table for performing weighting so that 22 is a D / A converter for converting a color arrangement into a television signal, and 23 is for displaying a television signal. 24 is a material identification device for identifying whether the material at the detected position is a material with a high atomic number or a material with a low atomic number, and 24A is a signal from two correction circuits A and B. 24B is a level comparator that classifies the values obtained by performing the difference calculation, 25 is a determination device for determining whether liquid is contained or foreign matter is mixed, and 25A is a pixel. , A material data memory for inputting a material identification value for each pixel, and 25c for analyzing data stored in 25B to determine how far the liquid has been filled and whether foreign matter has been detected. A material information control type gate circuit for determining whether or not contamination has occurred, 25d and 25e are gate circuits 25c
The liquid inspection recording unit and the foreign object inspection recording unit, which records which container does not contain liquid as specified and foreign matter is mixed, based on the result determined in step 2, contain liquid as specified This is an exclusion signal transmitter that sends an exclusion control command to remove the container from the line when the container is not used or contains foreign matter.

Next, the operation of the X-ray irradiation apparatus having the structure shown in FIGS. First, in FIG. 1, a container 4 is provided on a container transporting device 5 by an X-ray source 1 and an X-ray detector 3 opposed thereto.
Is transported so as to move between them. When the container 4 moves, when the light emitter 6 and the light receiver 7 detect the container, X-rays are emitted at a timing when a certain time elapses and the container passes between the X-ray source 1 and the X-ray detector 3. Is done.

The X-ray flux 2 emitted from the X-ray source 1 is
And enters the X-ray detectors 3 </ b> A and 3 </ b> B arranged closely in the traveling direction of the container transport device 5. As shown in FIG. 1, the X-ray detector 3A has no filter added to the X-ray irradiation surface, while the X-ray detector 3B has a filter added. (If the X-ray detector is two-dimensional, no filter is added to the X-ray irradiation surface on one of the adjacent detection elements,
A filter is added to the other. This allows 1
The X-ray detecting elements having the same height in the pair are changed in the quality of the X-ray incident on the detector and are incident. Each detection element is composed of, for example, a scintillator and a photodiode, and converts X-rays into electric signals. The signal is amplified by the amplifier 15, and the detection elements are switched in the multiplexers 16A and 16B.

Hereinafter, according to the block diagram of FIG.
Pre-signal processing is performed by A / D conversion of A and 17B and correction circuits of 18A and 18B. Next, the material identification device 24
In, first, a difference operation circuit 24A calculates a difference between signals from the two detectors of the X-ray detectors 3A and 3B. Further, in the level comparison 24B, it is determined whether the difference value is large or small. As described later, if the difference value is large, it is determined to be a low atomic number substance, and if it is small, it is determined to be a high atomic number substance (material identification).

On the other hand, data (image data in the case of two dimensions) obtained by the correction circuits 18A and 18B undergoes data change by the interface 19 and is stored in the storage device 20. The material identification value is also input to the storage device 20 from the level comparison 24B.

Data or image data from the storage device 20 is input to the raw data memory 25A, and the material identification value is input to the material data memory 25B from the storage device 20. Further, in 25c, for example, in a two-dimensional array, it is determined in order from the bottom whether the substance is a low atomic number substance or a high atomic number substance, and the position where the low atomic number substance changes to a high atomic number substance is determined. Is determined to have a liquid level. Also,
In the two-dimensional image data, the number of determination pixels of the high atomic number substance is counted, and if a certain number or more exists in a certain area, it is determined that a foreign substance has entered.

Next, in the liquid counter 25d, it is determined whether or not the liquid is within a specified value, and the foreign substance counter 25e counts whether or not there is any foreign substance in the container. Further, an instruction signal to be removed from the line by the rejection signal transmitter 26 is sent to the line by the rejection signal transmitter 26 for containers that do not conform to the prescribed rules.

On the other hand, data or image data is LU
At T21, the color scheme is weighted based on the comparison table, and converted to an analog signal by the D / A converter 22,
It is displayed on the television monitor 23.

A method of identifying material information at each detector position in the material identification device 24 will be described with reference to FIGS. FIG. 3 shows an example of X-ray attenuation characteristics of a high atomic number substance and a low atomic number substance, with the X-ray energy on the horizontal axis and the X-ray attenuation signal on the vertical axis. FIG. 3 shows that the difference in X-ray attenuation due to the difference in energy is larger in a high atomic number substance than in a low atomic number substance. FIG. 4 shows the relationship between the X-ray transmission signal and the thickness of the substance when the X-ray energy is changed to E1 and E2 in FIG. Since the high atomic number substance has a large X-ray attenuation coefficient, the X-ray transmission signal decreases with a small thickness compared to the low atomic number substance.

According to these figures, when an irradiation X-ray having a certain energy distribution passes through the side surface of the container 4,
It can be seen that the energy distribution of transmitted X-rays changes depending on whether each height is a low atomic number substance or a high atomic number substance. In the case of a low atomic number substance, it attenuates uniformly from low energy X-rays to high energy X-rays,
In the case of a high atomic number substance, the rate of attenuation of low energy X-rays with respect to high energy X-rays increases.

Next, when the transmitted X-rays pass through the filter in front of the X-ray detector 3B, the way of attenuation differs between the X-rays transmitted through the low atomic number substance and the X-rays transmitted through the high atomic number substance. . X-rays that have passed through a low atomic number substance have a high proportion of high energy X-rays, so the attenuation rate when passing through a filter is greater than that of a high atomic number substance. Therefore, if the difference between the X-ray detector 3B to which the filter is added and the X-ray detector 3A to which no filter is added is large, it can be determined that the substance is a low atomic number substance, and if the difference is small, it is a high atomic number substance.

Finally, examples of the judgment made according to the above-mentioned judgment method are shown in FIGS. However, FIGS. 5 to 7 show examples when the detector is two-dimensional. FIG.
A perspective image displayed on a two-piece steel can TV monitor without a material identification function, FIG. 8 is a perspective image displayed on a three-piece steel can TV monitor without a material identification function, and FIG. FIG. 6 is a perspective image displayed on a television monitor of a two-piece steel can having an identification function, and FIG. 6 is a perspective image displayed on a television monitor of a three-piece steel can having a material identification function.

First, the case of a two-piece can will be described with reference to FIGS. The two-piece can is roughly divided from FIG.
It is divided into three parts: a can lid part 80, a head space part 82 where no liquid is contained, and a liquid part 81. These are described as (A), (B), and (C) below. (A) Can lid part (B) Headspace part (C) Liquid containing part

Conventionally, as shown in FIG. 7 (c), when the amount of liquid is large, it overlaps with the portion containing the liquid, and in the conventional method having no material identification function, the can lid and the liquid portion are connected to each other. Had been determined. According to the present invention having the material identification function, it is possible to determine the material from the above (A) to (C) as shown in (A ′) to (C ′) as shown in FIG. Yes, and there is no erroneous determination. (A) Can lid portion The steel material is only a high molecular number material of several hundred μm, and the material judgment is a high atomic number material. (B) Headspace Site The steel material is only a high molecular number material of several hundred μm, and the material judgment is a high atomic number material. (C) Liquid-containing site Steel material is a polymer number substance of several hundred μm and liquid is several tens of meters.
m is the sum of the low atomic number substances, and since the amount of the low atomic number substances is sufficiently large, the material judgment is the low atomic number material.

Further, as shown in FIG. 5 (b), when a foreign matter 60 such as iron scrap is mixed in the container 4, a polymer number of several mm of iron scrap and a low atomic number substance of several tens mm of liquid are used. , And the material judgment is a high atomic number material. The number of pixels determined to be inorganic is counted, and a foreign substance is determined. The X-ray absorption becomes larger due to the inclusion of foreign matter than when only the liquid is used. However, the present invention makes it possible to make an unprecedented determination in that the material of the foreign matter can be known.

Next, the case of a three-piece can will be described with reference to FIGS. From FIG. 8, the three-piece cans are roughly divided
Can lid part 80, headspace part 8 not containing liquid
2, divided into four parts, a liquid part 81 and a bottom part. these,
These are described as (D), (E), (F), and (G) below. (D) Can lid part (E) Headspace part (F) Liquid containing part (G) Bottom part

Conventionally, in the headspace portion of FIG. 8 (b), since the X-ray absorption was large in the seam portion in the past, it was erroneously determined to be a liquid. Focusing on the fact that the width of the seam portion is narrower than the outer width of the product, a method of performing measurement a plurality of times and averaging was used, but it took time for determination, which hindered speeding up. As shown in FIG. 3, in the present invention having the material identification function, the above-described (D) to (G) are identified as the following (D ′) to (G ′), and only the liquid part is determined. And erroneous determination is eliminated. (D ′) Can lid portion Only a high molecular number material of several hundred μm of steel material is used, and the material judgment is a high atomic number material. (E ') Headspace site Only the high molecular number material of several hundred μm of the steel material is used, and the material judgment is a high atomic number material. Although the seam portion is also made of a high atomic number material, it is conventionally erroneously determined to be a liquid because of its high X-ray absorption. (F ') The part containing the liquid The sum of the high molecular number substance of several hundred μm of the steel material and the low atomic number substance of several tens of mm of the liquid, and the amount of the low atomic number substance is sufficiently large. Low atomic number material. The seam is made of a slightly higher low atomic number material. (G ') Lower can lid part The sum of a high molecular number substance of several hundred μm of steel material and a low atomic number substance of several tens of mm of liquid, and the amount of low atomic number substance is sufficiently large. Low atomic number material.

Further, if only the high atomic number material is counted by the determination device as shown in FIG. 6 (b), foreign substances can be detected as shown in FIG. 5 (b). For example, a case where a foreign matter such as a metal piece is mixed will be described. When metal pieces are mixed in the container, most of them sink to the bottom. In the bottom part, the liquid is several tens of mm
Therefore, it is usually determined that the substance has a low atomic number, but a portion containing a metallic foreign substance is determined to be a high atomic number. Thus, it is determined that the foreign matter has entered.

[0028]

As described above, according to the present invention, X
In the linear liquid amount inspection apparatus, it is possible to accurately determine to which level the liquid has been injected.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of the present invention.

FIG. 2 is a block diagram of the present invention.

FIG. 3 is an example of X-ray attenuation characteristics of a high atomic number substance and a low atomic number substance.

FIG. 4 shows a relationship between an X-ray transmission signal and a thickness of a substance.

FIG. 5 is a perspective image displayed on a television monitor of a two-piece steel can having a material identification function.

FIG. 6 is a perspective image displayed on a television monitor of a three-piece, steel can having a material identification function.

FIG. 7 is a perspective image displayed on a television monitor of a two-piece, steel can without a material identification function.

FIG. 8 is a perspective image displayed on a television monitor of a three-piece, steel can without a material identification function.

[Explanation of symbols]

3A, 3B: X-ray detector, 24: Material identification device, 24A
... Difference calculation circuit, 24B ... Level comparison, 25 ... Determination device, 25A ... Image data, 25B ... Material data, 25c
… Material information control type gate circuit, 25d… Liquid counter,
25e: Foreign matter counter, 26: Rejection signal transmitter

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2F014 AA07 FD10 2G001 AA01 BA11 CA01 DA02 DA09 EA06 GA01 GA06 HA13 LA02 MA02 PA11 QA10 2G088 EE29 FF02 JJ08 JJ09 KK07

Claims (2)

[Claims] An X-ray source for irradiating X-rays in a horizontal direction, and an X-ray detector arranged opposite to the X-ray source and having a plurality of X-ray detection elements arranged linearly in a vertical direction. A container transport device for moving a container so as to pass between the X-ray source and the X-ray detector, wherein the linearly arranged X-ray detector has two rows. Consisting of
Two types of layers having different X-ray wavelength selectivities are coated on the surfaces of the two rows, and the height of the two rows is determined based on the difference signal between the detection signals from the X-ray detection elements having the same height. Determining means for determining whether the object to be detected is a low atomic number substance or a high atomic number substance, and determining a liquid amount in the container; anddisplay means for displaying the determined result. An X-ray liquid volume inspection device characterized by the above-mentioned. 2. A two-dimensional X-ray detector comprising: an X-ray source for irradiating X-rays in a horizontal direction; a two-dimensional X-ray detector located opposite to the X-ray source; And a container transporter for moving the X-ray detector so as to pass between the X-ray source and the X-ray detector, wherein a wavelength is provided in front of the two-dimensionally arranged X-ray detection element. Two types of layers having different selectivities are alternately coated, and an object to be detected at each detection position is a low atomic number substance based on a difference signal between detection signals from a pair of adjacent X-ray detection elements. Or a high atomic number substance, determining means for determining whether a foreign substance has entered the container based on each of the determinations, and display means for displaying the determined result. Characteristic X-ray liquid inspection device.