JP2013251121A - X-ray inspection apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an X-ray inspection apparatus capable of highly accurately detecting breaking of a filament.SOLUTION: An X-ray inspection apparatus 1 includes: an X-ray tube 12 having plural filaments, a first filament 71 and a second filament 72, in a cathode; an X-ray tube current detector 76 for detecting current flowing from the cathode to an anode of the X-ray tube 12 as X-ray tube current; and a controller 46 for determining breaking of any of the first filament 71 and the second filament 72 on the basis of the X-ray tube current detected by the X-ray tube current detector 76 when voltage is applied from the cathode to the anode of the X-ray tube 12.

Description

  The present invention relates to an X-ray inspection apparatus for detecting foreign matter mixed in an inspection object (inspection object) such as meat, fish, processed food, and pharmaceutical, and in particular, an object to be inspected by being irradiated from an X-ray generator. The present invention relates to an X-ray inspection apparatus for detecting foreign matter by detecting transmitted X-rays with an X-ray detector.

  For example, an X-ray inspection apparatus has been conventionally used to detect the presence or absence of foreign matter in an inspection object such as food. In this type of conventional X-ray inspection apparatus, X-rays are irradiated to the object to be transported, and it is detected from the amount of transmitted X-rays whether foreign matter is mixed in the object to be inspected. Inspecting for foreign objects.

  Further, in this type of X-ray inspection apparatus, the filaments inside the X-ray tube become thinner due to evaporation of the filaments due to X-ray irradiation, and eventually the wire breaks and X-rays cannot be irradiated. End up.

  Conventionally, in this type of X-ray inspection apparatus, filament breakage is predicted by predicting filament breakage based on the filament voltage applied to the filament and the filament current flowing through the filament, and notifying the user of the filament breakage notice. Thus, there is known a technique that avoids being unusable (see, for example, Patent Document 1).

  In the technique described in Patent Document 1, it is possible to avoid the filament from being suddenly disconnected and becoming unusable. However, the filament cannot be exchanged immediately after the filament disconnection notice is continued. If the filament breaks using an X-ray tube, the use of the device must be interrupted and the X-ray tube replaced.

  Therefore, as a countermeasure to this problem, one filament is provided with two filaments in one X-ray tube, and the filament breakage is detected based on the fact that the filament current flowing on the primary side of the filament transformer is less than the specified value. A technique is known in which the remaining filament is switched to use (for example, see Patent Document 2).

JP-A-8-64388 JP 2004-296242 A

  However, in the X-ray inspection apparatus described in Patent Document 2, since the filament current is detected on the primary side of the filament transformer, the state on the secondary side of the filament transformer cannot be determined in detail, so that disconnection is detected. There was a problem that accuracy was inferior.

  Accordingly, the present invention has been made to solve the conventional problems as described above, and an object thereof is to provide an X-ray inspection apparatus capable of detecting a breakage of a filament with high accuracy.

  An X-ray inspection apparatus according to the present invention includes an X-ray tube having a plurality of filaments as a cathode, an X-ray tube current detecting means for detecting current flowing from the cathode to the anode of the X-ray tube as an X-ray tube current, Disconnection determining means for determining that any of the plurality of filaments is disconnected based on the X-ray tube current detected by the X-ray tube current detecting means when a voltage is applied from the cathode to the anode of the X-ray tube; It is provided with.

  With this configuration, the filament breakage is determined based on the X-ray tube current detected by the X-ray tube current detection means on the secondary side of the filament transformer that supplies a plurality of electric power. Disconnection can be detected.

  The X-ray inspection apparatus according to the present invention further includes X-ray tube voltage detecting means for detecting a voltage applied from the cathode of the X-ray tube to the anode as an X-ray tube voltage, and the disconnection determining means includes the X-ray tube detecting means. It is determined that any one of the plurality of filaments is disconnected based on the X-ray tube voltage detected by the X-ray tube voltage detection means when a voltage is applied from the cathode to the anode of the tube.

  With this configuration, the filament breakage based on the X-ray tube current and the X-ray tube voltage detected by the X-ray tube current detection means and the X-ray tube voltage detection means on the secondary side of the filament transformer that supplies a plurality of electric power. Therefore, the filament breakage can be detected with high accuracy.

  In addition, the X-ray inspection apparatus according to the present invention is characterized by comprising a breakage notification means for notifying that the breakage of the filament is determined by the breakage determination means.

  With this configuration, the disconnection notifying means notifies that the filament is disconnected, so that the user can quickly cope with the filament disconnection.

  The X-ray inspection apparatus according to the present invention further includes a filament switching unit that switches a filament that supplies power to any one of the plurality of filaments, and the disconnection determination unit sets the filament that supplies power to the filament. The disconnection is judged by sequentially switching by the switching means.

  With this configuration, it is possible for the breakage determination means to determine the breakage of the filament and which filament is broken, and to notify the breakage notification means, and the user can quickly cope with the breakage of the filament. .

  The present invention can provide an X-ray inspection apparatus capable of detecting breakage of a filament with high accuracy.

1 is a perspective view showing a schematic configuration of an X-ray inspection apparatus according to an embodiment of the present invention. It is a figure which shows the side surface and internal structure of the X-ray inspection apparatus which concern on embodiment of this invention. It is a block diagram which shows the structure of the detection part of the X-ray tube current and X-ray tube voltage of the X-ray generator of the X-ray inspection apparatus which concerns on embodiment of this invention. It is a block diagram which shows the structure of the filament switching part of the X-ray generator of the X-ray inspection apparatus which concerns on embodiment of this invention. (A) shows the relationship between the X-ray tube voltage and the X-ray tube current when the filament is not disconnected, and (b) shows the relationship between the X-ray tube voltage and the X-ray tube current when the filament is disconnected. It is a figure which shows a relationship.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  First, the configuration will be described.

  As shown in FIG. 1, the X-ray inspection apparatus 1 includes a transport unit 2 and a detection unit 3 inside a housing 4, and a display unit 5 at the upper front of the housing 4.

  The transport unit 2 sequentially transports the inspection object W, which is an inspection object, at predetermined intervals. This conveyance part 2 is comprised by the belt conveyor arrange | positioned horizontally within the housing | casing 4, for example. The transport unit 2 serves as a transport surface for the inspection object W loaded from the carry-in port 7 at a transport speed set in advance by driving the drive motor 6 shown in FIG. 1 toward the carry-out port 8 side (X direction in the figure). The belt surface 2a is conveyed. A space passing through the belt surface 2 a from the carry-in entrance 7 to the carry-out exit 8 within the housing 4 forms a transport path 21.

  The detection unit 3 irradiates the inspection object W sequentially conveyed with X-rays in the inspection space 22 in the middle of the conveyance path 21 and detects X-rays transmitted through the inspection object W. An X-ray generator 9 disposed at a predetermined height above the inspection space 22 in the middle of 21 and an X-ray detector 10 disposed opposite to the X-ray generator 9 in the transport unit 2 are provided. ing.

  An X-ray generator 9 as an X-ray generation source has a configuration in which a cylindrical X-ray tube 12 provided in a metal box 11 is immersed in insulating oil (not shown). X-rays are generated by irradiating an anode target with an electron beam from 12 cathodes. The X-ray tube 12 is arranged such that its longitudinal direction is the conveyance direction (X direction) of the inspection object W. X-rays generated by the X-ray tube 12 are irradiated toward the lower X-ray detector 10 so as to cross the transport direction (X direction) in a substantially triangular screen shape by a slit (not shown). It has become. As will be described later, the X-ray tube 12 includes a plurality of (two in the present embodiment) filaments in the cathode.

  The X-ray detector 10 has a plurality of detection elements arranged in a straight line in the Y direction orthogonal to the transport direction on the plane in the transport direction (X direction) of the object W to be transported. Specifically, the X-ray detector 10 includes a photodiode (not shown) as a plurality of detection elements arranged in a line and a scintillator (not shown) provided on the photodiode. And a line sensor (not shown). Further, as shown in FIG. 2, the X-ray detector 10 includes an A / D conversion unit 41. The A / D conversion unit 41 converts luminance value data from the photodiode into digital data, and the density is changed. The data is output as an X-ray image. The X-ray detector 10 detects X-rays that pass through the inspection object W by a line sensor that extends linearly in a direction (Y direction) orthogonal to the plane of the conveyance direction (X direction) of the inspection object W. Then, a grayscale image corresponding to the detected amount of X-rays is output.

  As shown in FIG. 2, X-ray shielding shielding curtains 16 are suspended and arranged at a plurality of locations along the conveyance direction (X direction) on the ceiling portion 21 a in the conveyance path 21. The shielding curtain 16 is composed of a rubber sheet mixed with lead powder that shields X-rays and processed into a good shape (a state in which the upper part is connected and the lower part is divided into strips), and is conveyed from the inspection space 22. This prevents X-rays from leaking outside the housing 4 via the path 21. In the present embodiment, two shielding curtains 16 are provided between the carry-in entrance 7 and the inspection space 22 and between the examination space 22 and the carry-out exit 8, respectively. Even when a gap is generated due to elastic deformation due to contact with the inspection object W, the other shielding curtain 16 shields X-rays, so that leakage of X-rays can be prevented without exceeding the leakage reference amount. An inner space surrounded by the shielding curtain 16 in the conveyance path 21 constitutes an inspection space 22.

  The X-ray inspection apparatus 1 receives the X-ray image from the X-ray detector 10, and displays and outputs a control circuit 40 that inspects the presence or absence of a foreign substance in the inspection object W, and inspection results by the control circuit 40. The display unit 5 and a setting operation unit 45 for inputting various parameters and the like to the control circuit 40 are provided.

  The display unit 5 is composed of a flat display or the like, and performs display output for the user. The display unit 5 displays the pass / fail judgment result of the inspected object W with characters or symbols such as “OK” and “NG”, and the inspection results such as the total number of inspections, the number of non-defective products, and the total number of NG as default settings. Alternatively, the screen is displayed based on a request by a predetermined key operation from the setting operation unit 45.

  The setting operation unit 45 includes a plurality of keys and switches operated by the user, and performs setting input of various parameters and the like to the control circuit 40 and selection of an operation mode. The display unit 5 and the setting operation unit 45 may be integrally configured as a touch panel display.

  The control circuit 40 performs X-ray image storage unit 42 that stores the X-ray image received from the X-ray detector 10, and performs image processing for extracting filters and features from the data read from the X-ray image storage unit 42. An image processing unit 43 to be applied, and a determination unit 44 that determines whether the inspection object W is a foreign object from the image-processed data and determines whether or not a foreign object is mixed.

  Further, the control circuit 40 includes a control unit 46 configured to include a CPU and a memory as a control program storage area or a work area. The control unit 46 determines the breakage of the filament of the X-ray tube 12 when the operation mode is the filament inspection mode.

  The operation mode executed by the control circuit 40 includes a filament inspection mode in addition to an operation mode that is a normal operation mode. The operation mode is an operation mode in which image processing is performed on an X-ray image of detection data to check for the presence of foreign matter. The filament inspection mode is an operation mode for inspecting filament breakage.

  As shown in FIG. 3, the X-ray tube 12 of the X-ray generator 9 has two filaments, a first filament 71 and a second filament 72 as a cathode, and a target 73 as an anode. By switching the filament to be used from one of the first filament 71 and the second filament 72 to the other, when one filament breaks, the other filament is used, and the X-ray tube 12 can be continuously replaced. The X-ray inspection apparatus 1 can be operated.

  The first filament 71 and the second filament 72 have the same focal spot size, and the focal spot size does not change when switching between the first filament 71 and the second filament 72 is performed. Switching between the first filament 71 and the second filament 72 is performed by a filament switching unit described later.

  The X-ray generator 9 includes a full-wave rectification / inverter circuit 74, a high voltage transformer 75, an X-ray tube current detector 76, and an X-ray tube voltage detector 77.

  The full-wave rectification / inverter circuit 74 performs full-wave rectification and smoothing of the alternating current output from the alternating current power supply 78 and converts it into alternating current output by switching processing.

  The high-voltage transformer 75 outputs the output from the full-wave rectification / inverter circuit 74 from the primary side to the secondary side, and rectifies and converts it into a DC output by a built-in high-voltage rectifier (not shown). The direct current output is applied to the X-ray tube 12 via a high-voltage cable (not shown), whereby the heat released from the heated cathode filament (the first filament 71 or the second filament 72) in the X-ray tube 12. The electrons are accelerated and collide with the target 73 of the anode, so that the X-ray tube 12 generates X-rays.

  The X-ray tube current detector 76 detects the amount of electrons flowing from the cathode (first filament 71, second filament 72) of the X-ray tube 12 to the anode (target 73), that is, the X-ray tube current. The high voltage transformer 75 and the filaments (the first filament 71 and the second filament 72) are connected in series. A detection signal from the X-ray tube current detector 76 is input to the control unit 46 of the control circuit 40.

  The X-ray tube voltage detector 77 detects an X-ray tube voltage applied between the cathode (first filament 71, second filament 72) and the anode (target 73) of the X-ray tube 12. The X-ray tube 12 is connected in parallel to both poles. A detection signal from the X-ray tube voltage detector 77 is input to the control unit 46 of the control circuit 40.

  The value of the X-ray tube current flowing through the X-ray tube 12 is controlled so as to become the target tube current value. The X-ray tube current is controlled by, for example, obtaining a difference between an X-ray tube current value and a target tube current value by an error amplifier (not shown), and a filament heating circuit (not shown) converts the filament current into a target tube current value based on this difference. It is performed by controlling so that.

  As shown in FIG. 4, the X-ray tube current detector 76 includes a filament switching unit 79 that switches the filament to be used between the first filament 71 and the second filament 72.

  In FIG. 4, high voltage power is supplied to the first filament 71 from the secondary side of the first filament transformer 81, and high voltage power is supplied to the second filament 72 from the secondary side of the second filament transformer 82. It has come to be.

  The filament switching unit 79 switches the power supply from the power supply device 80 between the primary side of the first filament transformer 81 or the primary side of the second filament transformer 82, so that the filament to be used is the first filament. It switches between 71 and the 2nd filament 72. The filament switching unit 79 performs filament switching in response to a switching signal from the control unit 46 of the control circuit 40. 4 corresponds to the full-wave rectification / inverter circuit 74 of FIG.

  Here, when the filament (for example, the first filament 71) is not disconnected, as shown in FIG. 5A, when the X-ray tube voltage is output, the X-ray tube voltage is set according to the X-ray tube voltage. The tube current increases. On the other hand, when the filament is disconnected, the X-ray tube current does not change even if the X-ray tube voltage is output, as shown in FIG.

  Therefore, the control unit 46 of the control circuit 40 detects the disconnection of the filament based on the detection signal from the X-ray tube current detector 76 when the X-ray tube voltage is output. Specifically, when the operation mode is the filament inspection mode, the control unit 46 determines that the filament is disconnected when the X-ray tube current is in the state shown in FIG. When the state is 5 (a), it is determined that the filament is not broken.

  The control unit 46 determines the disconnection by switching the filament for supplying power between the first filament 71 and the second filament 72 by the filament switching unit 79.

  The control unit 46 simultaneously monitors not only the detection signal from the X-ray tube current detector 76 but also the detection signal from the X-ray tube voltage detector 77, so that the X-ray tube current with respect to the change in the X-ray tube voltage. The breakage of the filament may be determined from the change in.

  When the control unit 46 detects the breakage of the filament, the display unit 5 informs that the filament is broken. The display unit 5 is notified of which side of the first filament 71 and the second filament 72 is disconnected.

  In addition, when the control part 46 detects the disconnection of one filament of the 1st filament 71 and the 2nd filament 72, it outputs a switching signal to the filament switching part 79, and supplies electric power to the other filament which is not disconnected. You may make it supply.

  As described above, the X-ray inspection apparatus 1 according to the present embodiment includes the X-ray tube 12 having the first filament 71 and the second filament 72 that are a plurality of filaments as the cathode, and the cathode to anode of the X-ray tube 12. The X-ray tube current detector 76 detects the current flowing through the X-ray tube current, and the X-ray tube current detected by the X-ray tube current detector 76 when a voltage is applied from the cathode of the X-ray tube 12 to the anode. And a control unit 46 that determines that either the first filament 71 or the second filament 72 is disconnected based on the above.

  With this configuration, the control unit 46 determines that the filament is broken based on the X-ray tube current detected by the X-ray tube current detector 76 on the secondary side of the first filament transformer 81 and the second filament transformer 82. Therefore, the breakage of the filament can be detected with high accuracy.

  The X-ray inspection apparatus 1 according to the present embodiment includes an X-ray tube voltage detector 77 that detects a voltage applied from the cathode of the X-ray tube 12 to the anode as an X-ray tube voltage, and the control unit 46 includes And determining that one of the plurality of filaments is disconnected based on the X-ray tube voltage detected by the X-ray tube voltage detector 77 when a voltage is applied from the cathode of the X-ray tube 12 to the anode. To do.

  With this configuration, based on the X-ray tube current and the X-ray tube voltage detected by the X-ray tube current detector 76 and the X-ray tube voltage detector 77 on the secondary side of the first filament transformer 81 and the second filament transformer 82. Since the filament breakage is determined, the filament breakage can be detected with high accuracy.

  In addition, the X-ray inspection apparatus 1 according to the present embodiment includes the display unit 5 that notifies that the control unit 46 has determined that the filament is broken.

  With this configuration, since the fact that the filament is disconnected is displayed on the display unit 5 under the control of the control unit 46, the user can quickly cope with the disconnection of the filament.

  In addition, the X-ray inspection apparatus 1 according to the present embodiment includes a filament switching unit 79 that switches any one of a plurality of filaments to supply power to one filament, and the control unit 46 supplies the power to the filament. Are sequentially switched by the filament switching unit 79 to determine the disconnection.

  With this configuration, since the filament breakage and which filament breakage is displayed on the display unit 5 under the control of the control unit 46, the user can quickly cope with the filament breakage.

  As described above, the X-ray inspection apparatus according to the present invention has the effect of being able to detect the breakage of the filament with high accuracy, and the X-rays irradiated from the X-ray generator and transmitted through the object to be inspected. It is useful as an X-ray inspection apparatus that detects an inspection object by detecting with an X-ray detector.

DESCRIPTION OF SYMBOLS 1 X-ray inspection apparatus 2 Conveyance part 2a Belt surface 3 Detection part 4 Case 5 Display part (disconnection notification means)
DESCRIPTION OF SYMBOLS 7 Carry-in port 8 Carry-out port 9 X-ray generator 10 X-ray detector 11 Box 12 X-ray tube 16 Shielding curtain 21 Conveyance path 21a Ceiling part 22 Inspection space 40 Control circuit 41 A / D conversion part 42 X-ray image memory | storage part 43 Image processing unit 44 Judgment unit 45 Setting operation unit 46 Control unit (disconnection judgment means)
71 1st filament 72 2nd filament 73 Target (anode)
74 Full-wave rectification and inverter circuit 75 High voltage transformer 76 X-ray tube current detector (X-ray tube current detection means)
77 X-ray tube voltage detector (X-ray tube voltage detection means)
78 AC power supply 79 Filament switching unit (filament switching means)
80 power supply device 81 first filament transformer 82 second filament transformer W object to be inspected

Claims (4)

An X-ray tube (12) having a plurality of filaments (71, 72) as a cathode;
X-ray tube current detecting means (76) for detecting a current flowing from the cathode to the anode of the X-ray tube as an X-ray tube current;
Disconnection determination means for determining that any of the plurality of filaments is disconnected based on the X-ray tube current detected by the X-ray tube current detection means when a voltage is applied from the cathode to the anode of the X-ray tube. 46), and an X-ray inspection apparatus. X-ray tube voltage detecting means (77) for detecting a voltage applied from the cathode to the anode of the X-ray tube as an X-ray tube voltage;
When the disconnection judging means has disconnected any of the plurality of filaments based on the X-ray tube voltage detected by the X-ray tube voltage detecting means when a voltage is applied from the cathode of the X-ray tube to the anode. The X-ray inspection apparatus according to claim 1, wherein the determination is made.   The X-ray inspection apparatus according to claim 1, further comprising a disconnection notification unit (5) that notifies that the disconnection of the filament is determined by the disconnection determination unit. Filament switching means (79) for switching the filament for supplying power to any one of the plurality of filaments,
The X-ray inspection apparatus according to any one of claims 1 to 3, wherein the disconnection determining means performs a disconnection determination by sequentially switching the filament to which power is supplied by the filament switching means.

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