JP2005121468A - Food foreign substance inspection device for hair or the like using fluorescent x-ray - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a food foreign matter inspection device capable of detecting foreign matter comprising a light element such as a hair intermingled in food or the like. <P>SOLUTION: In this food foreign matter inspection device having an X-ray generation means for allowing an electron beam from an electron source to hit on an X-ray generation target to generate the X-ray, the food which is an inspection object is irradiated with the X-ray, and a fluorescent X-ray generated from the food is detected, to thereby detect a foreign matter intermingled in the food. In the device, a fluorescent X-ray detection means for detecting the fluorescent X-ray is arranged on the oblique upside or on the oblique downside of the food and out of an arrival region of the X-ray generated from the X-ray generation target. The device is also equipped with a florescent X-ray analysis means for specifying existence and the kind of the foreign matter intermingled in the food by analyzing the kind and the content of an element included in the food based on a fluorescent X-ray detection signal from the fluorescent X-ray detection means, and a display means for displaying the analysis result. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a food foreign object inspection apparatus, and more particularly to a food foreign object inspection apparatus using fluorescent X-rays that enables detection of foreign substances composed of light elements such as hair mixed in food.

In the production of processed foods, it is necessary to prevent foreign matter such as metal pieces, bone pieces or hair from being mixed in order to maintain quality, but it is difficult to completely prevent foreign matter from entering the manufacturing process. In US Pat. No. 5,836, the presence or absence of foreign matter is checked using an inspection device, and processed food containing foreign matter is excluded.
Since the inspection needs to be performed non-destructively, normally, an X-ray inspection apparatus is used to transmit X-rays to the object to be inspected, and the transmitted X-rays are detected and image processing is performed to detect foreign matters. .
However, the conventional X-ray inspection apparatus can detect foreign substances such as metals made of relatively heavy elements, but a clear intensity difference cannot be obtained by image analysis of X-ray fluoroscopic images of foreign substances made of light elements such as hair. Detection was impossible by image processing using fluoroscopic X-rays.
JP 2002-139458 A

  The present invention has been made in view of the problems of the prior art, and an object of the present invention is to provide a food foreign matter inspection apparatus that can detect foreign matters composed of light elements such as hair mixed in food.

  The present invention relates to a food foreign object inspection apparatus that enables detection of foreign substances consisting of light elements such as hair mixed in food, etc. The above object of the present invention is to apply an electron beam from an electron source to an X-ray generation target. X-ray generating means for generating X-rays, irradiating the food to be inspected with X-rays, detecting fluorescent X-rays generated from the food, and detecting foreign matter mixed in the food In the food foreign body inspection apparatus to be performed, the fluorescent X-ray detection means for detecting the fluorescent X-rays is disposed obliquely above or below the food and outside the X-ray generation area generated from the X-ray generation target. In addition, by analyzing the type and content of the element contained in the food based on the fluorescent X-ray detection signal, the fluorescent X-ray analysis means for specifying the presence and type of foreign matter mixed in the food, Display analysis results It is accomplished by further comprising display means that.

  Further, the object of the present invention is to arrange a plurality of fluorescent X-ray detection means obliquely above or below the food and outside the X-ray generation area generated from the X-ray generation target. Effectively achieved.

  Furthermore, the above-mentioned object of the present invention is achieved more effectively by making the fluorescent X-ray detection means a proportional counter or a semiconductor linear detector capable of highly sensitive position detection.

Furthermore, the above object of the present invention can be achieved more effectively by providing a collimator in front of the fluorescent X-ray entrance of the fluorescent X-ray detection means.
Furthermore, the above object of the present invention is more effectively achieved by the food foreign object inspection apparatus characterized in that it has a function of displaying in which part of the food a foreign object is mixed.

  According to the food foreign matter inspection device such as hair using the fluorescent X-ray according to the present invention, it is possible to detect the contamination of foreign matters composed of light elements such as hair, which was impossible with the conventional food foreign matter inspection device, In addition, there is an effect that it is possible to specify a place where foreign substances are mixed.

The food foreign matter inspection apparatus according to the present invention irradiates food to be inspected with X-rays, detects fluorescent X-rays of elements peculiar to hair and other foreign matters (secondary characteristic X-rays by X-ray irradiation), Analyzes are performed to detect contamination of hair and the like, and to determine whether food quality is good or bad. That is, when an analysis result as shown in FIG. 1 is obtained, the peak position on the horizontal axis represents the type of element, and the vertical axis represents the concentration of the contained element. As a result, it is possible to specify what the foreign matter is.
The protein keratin that constitutes hair, like wool, contains sulfur as a major feature and a small amount of calcium in the center. This is a feature not found in other frozen foods and dry foods. Therefore, the main point of the present invention is to detect hair contamination by efficiently and accurately extracting S and Ca element signals with fluorescent X-rays.

Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the drawings.
FIG. 2 shows a first embodiment of a food foreign matter inspection apparatus for detecting foreign matters mixed in food according to the present invention. In the figure, an X-ray generator generates an X-ray by applying an electron beam from an electron source to an X-ray generation target. When the generated X-ray is irradiated to a food to be inspected, it is omnidirectional. X-ray fluorescence having a wavelength peculiar to the constituent element of the object to be inspected is generated. Of the generated fluorescent X-rays, those incident on the fluorescent X-ray detector disposed obliquely above (indicated by solid lines) or diagonally below (indicated by dotted lines) of the object to be inspected are converted into electrical signals. The
The fluorescent X-ray detector is disposed obliquely above or obliquely below the object to be inspected for the following reason. That is, continuous X-rays and characteristic X-rays are emitted from the X-ray generator, and in particular, continuous X-rays are irradiated downward along the incident direction of electrons. Therefore, even if a fluorescent X-ray detector is placed directly under the object to be inspected, the continuous X-rays are in the background and the fluorescent X-ray cannot be measured. Therefore, the X-ray generator is obliquely above or below the object to be inspected. The fluorescent X-ray detector is arranged outside the direct X-ray arrival area from (in this example, diagonally above or diagonally below the food).
FIG. 3 is a perspective view of the food foreign object inspection apparatus of FIG. 2 and shows that the incident surface of the fluorescent X-ray detector is arranged so as to be perpendicular to the moving direction of the conveyor.

FIG. 4 schematically shows the case where a one-dimensional fluorescent X-ray detector (line sensor) is used, in which a plurality of semiconductor detection elements are arranged in a line. As the semiconductor detection element, CdTe (cadmium telluride semiconductor) having high detection sensitivity without requiring cooling can be used. In addition, the proportional counter capable of position detection is also effective in that it has higher sensitivity, although the resolution is somewhat inferior to that of the semiconductor detection element.
The signal output from the fluorescent X-ray detector is input to the analysis PC via a pulse height analyzer (wave height analyzer), and is detected based on the detection information of the fluorescent X-ray and the set value for specifying each element. An analysis process of the element of the inspection object is performed.
In the PC for analysis, the detection of hair is determined on the basis of the proportionality or pattern matching between the intensity of fluorescent X-rays of S and Ca from the hair and each component. Further, in order to increase the detection accuracy, absorption correction processing and background noise called background are removed.

  FIG. 5 is a diagram showing a case where a one-dimensional fluorescent X-ray detector is used as a detector and a collimator is provided in front of each detection element in order to obtain higher detection position accuracy. The performance of the collimator is determined by the correlation between detection sensitivity and detection position accuracy. The collimator has the function of allowing only the vertically incident radiation to pass through the detector, and most are made of lead. The fluorescent X-ray detector, the pulse height analyzer, and the analysis PC constitute an energy dispersive fluorescent X-ray analyzer, and a commercially available apparatus can be used.

  In addition, in the example shown in FIG. 3, although the X-ray irradiated from the said X-ray generator is irradiated to the food in fan shape (planar shape), you may irradiate to cone shape. In the case of fan-shaped irradiation, a two-dimensional image can be obtained by moving the object to be inspected by a one-dimensional detector (line sensor) and a conveyor, but the amount of signal is increased by providing an X-ray reflector. And a clearer image can be obtained. By combining this two-dimensional image and the structure for detecting hair, it is possible to display on which screen the hair is present on the screen (display means) of the analysis PC. The existence position can be identified and displayed by other colors and marks.

  The second embodiment of the food foreign object inspection apparatus according to the present invention corresponds to the case where a plurality of fluorescent X-ray detectors are provided in the first embodiment (not shown). This is provided to improve sensitivity and prevent detection errors in consideration of absorption in the object to be inspected and in the air because the intensity of fluorescent X-ray is very weak and energy is low. is there. When a plurality of fluorescent X-ray detectors are provided, two fluorescent X-ray detectors may be arranged obliquely above the object to be inspected, both of them may be obliquely below, or one may be obliquely upward. The other one may be obliquely downward. Needless to say, the number of fluorescent X-ray detectors may be three or more.

It is a figure which shows the model of an elemental analysis result. It is a figure which shows the 1st Example of the food foreign material inspection apparatus which concerns on this invention. 1 is a perspective view of a first embodiment of a food foreign object inspection apparatus according to the present invention. A case where a one-dimensional fluorescent X-ray detector (line sensor) is used is schematically shown. It is a figure at the time of providing a collimator in front of a fluorescent X-ray detector.

Claims (5)

X-ray generation means for generating X-rays by applying an electron beam from an electron source to an X-ray generation target, irradiating the food to be inspected with the X-rays, and generating fluorescent X-rays generated from the food In the food foreign matter inspection apparatus that detects and detects foreign matters such as hair mixed in the food,
The fluorescent X-ray detection means for detecting the fluorescent X-ray is disposed obliquely above or below the food and outside the X-ray generation area generated from the X-ray generation target,
Fluorescence that identifies the presence and type of foreign matter mixed in the food by analyzing the type and content of the element contained in the food based on the fluorescent X-ray detection signal from the fluorescent X-ray detection means A food foreign matter inspection apparatus for detecting foreign matter mixed in food, further comprising X-ray analysis means and display means for displaying an analysis result.   2. The fluorescent X-ray detection means is arranged in a plurality obliquely above or obliquely below the food and outside the X-ray generation area generated from the X-ray generation target. Food foreign matter inspection device that detects foreign matter mixed in food.   3. The food for detecting foreign matter mixed in food according to claim 1, wherein the fluorescent X-ray detection means is a proportional counter or a semiconductor linear detector capable of highly sensitive position detection. Foreign matter inspection device.   4. A food foreign object for detecting a foreign substance mixed in food according to claim 1, wherein a collimator is provided in front of the fluorescent X-ray entrance of the fluorescent X-ray detection means. Inspection device.   The food foreign matter inspection apparatus for detecting foreign matter mixed in food according to any one of claims 1 to 4, further comprising a function of displaying which part of the food contains foreign matter.

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