JP2017106729A - Device for inspecting internal pressure of hermetically sealed container - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inspection accuracy of an internal pressure by detecting vibrations in a sound test of the hermetically sealed container and an internal pressure detection device of the hermetically sealed container capable of enhancing the determination accuracy of the quality of the hermetically sealed container based on the inspection accuracy.SOLUTION: An internal pressure detection device of a hermetically sealed container 1 is provided with a lid part 5 on at least one of an upper end and a lower end of a body part 4, and a striking force is applied to the lid part 5 so as to generate sounds or vibrations and inspects the internal pressure based on the sounds and the vibrations. The internal pressure detection device is provided with displacement sensors 12 and 15 for measuring the displacement of the lid part 5 generating the sounds or the vibrations by being given a striking force. A displacement waveform is obtained and a frequency of the displacement waveform is calculated based on the displacement of the lid part 5 measured by the displacement sensors 12 and 15, and the quality of the internal pressure is determined based on the frequency.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an apparatus for inspecting an internal pressure of a sealed container such as a three-piece can or a bottle-type can, and more particularly to an internal pressure inspection apparatus for a metal can.

  An example of this type of device is described in Patent Document 1 and Patent Document 2. These devices are configured to apply a striking force to the sealed container to generate sound or vibration, and analyze the frequency of the sound or vibration to detect an abnormality in internal pressure, that is, an abnormality in the sealed container. Specifically, the device described in Patent Document 1 generates a magnetic force when energized, and generates a suction force or a repulsive force with the sealed container by the magnetic force to apply a striking force to the sealed container. And a microphone for detecting the sound and vibration generated in the sealed container by the impact force and a waveguide for guiding the sound and vibration to the microphone. And, when the frequency of the sound or vibration detected by the microphone is in the frequency band corresponding to the appropriate internal pressure, it is determined as a non-defective product when it is out of the frequency band. Has been. Moreover, in the apparatus described in Patent Document 2, an optical microphone is used instead of the microphone. The optical microphone includes a reflective film that is vibrated by sound and vibration, a light transmitting unit that irradiates light to the reflective film, a light receiving unit that receives light reflected from the reflective film, and reflected light received by the light receiving unit. And a photodetector for conversion into an electric signal. That is, the reflection film is vibrated by sound or vibration generated in the sealed container to be inspected, and the vibration of the reflection film is optically detected.

JP 49-34376 JP 2003-215116 A

  In the configuration described in Patent Document 1, the abnormality of internal pressure is determined by detecting sound and vibration generated in a sealed container to be inspected with a microphone. That is, it is configured to obtain a signal through a sound that is vibration of air. Therefore, there is a possibility that the accuracy of determining the internal pressure is deteriorated depending on the environment where the sealed container and the microphone are placed, the state of the air interposed between the two, and the like. For example, it is difficult to avoid resonance between the sound and vibration generated in the sealed container and the sound and vibration reflected from the inner surface of the coil or waveguide. When a resonance phenomenon occurs, the frequency of sound and vibration becomes a so-called overtone that is an integral multiple of the natural frequency of the sealed container that is the object of inspection, and the overtone is detected stronger than the natural frequency of the sealed container that is the object of inspection. Then, there is a possibility that even if the sealed container to be inspected is a so-called defective product, it is determined as a non-defective product.

  In the configuration described in Patent Document 2, there is a possibility that the sound or vibration generated from the sealed container and the sound or vibration reflected by the reflective film may resonate. That is, even with the configuration described in Patent Document 2, erroneous determination due to the resonance phenomenon may occur in the same manner.

  This invention is made paying attention to said technical subject, Comprising: The vibration in the punching test of a sealed container is detected without passing through air, and the inspection accuracy of the internal pressure, and the accuracy of determining the quality of the sealed container based thereon It is an object of the present invention to provide a sealed container internal pressure inspection device capable of improving the above.

  In order to achieve the above object, the present invention is provided with a lid on at least one of the upper end and the lower end of the trunk, and gives a striking force to the lid to generate sound or vibration. In an internal pressure inspection device for a sealed container that inspects an internal pressure based on the sound or vibration, a displacement sensor that measures the displacement of the lid portion that is applied with the striking force and generates the sound or vibration is provided, A displacement waveform is obtained based on the displacement of the lid portion measured by a displacement sensor, the frequency of the displacement waveform is calculated, and the quality of the internal pressure is judged based on the frequency. It is characterized by that.

  Further, in the present invention, a striking portion for generating the striking force is provided, the striking portion is formed in a shape corresponding to the shape of the lid portion, and the displacement sensor is located at the center side portion of the lid portion. It may be comprised so that it may measure.

  Furthermore, in this invention, the displacement sensor includes a laser Doppler sensor configured to detect a vibration speed of the lid portion, and a laser displacement sensor configured to detect a distance between the lid portion and It may be at least one of these.

  In the present invention, the striking part and the displacement sensor may be provided to be movable relative to the lid part in a direction along a plane parallel to the lid part.

  According to the present invention, the displacement of the vibrating lid is detected by the displacement sensor, the displacement waveform is determined based on the displacement, the frequency of the displacement waveform is calculated, and the internal pressure is determined based on the frequency. That is, since the displacement of the lid is detected without passing through the sound of air vibration, the accuracy of the internal pressure is deteriorated due to the resonance phenomenon or the state of the air, or the accuracy of the internal pressure is determined due to the deterioration of the inspection accuracy. It is possible to avoid or suppress the situation that gets worse. Moreover, in this invention, since the quality of an internal pressure can be determined based on the displacement of the cover part measured with the displacement sensor, the structure of an apparatus can be simplified and addition to the existing installation is easy.

It is a figure for demonstrating an example of a structure of the internal pressure test | inspection apparatus based on this invention. It is a figure which shows the displacement waveform based on the displacement of the bottom cover detected by the laser displacement sensor. It is the figure which carried out FFT conversion of the displacement waveform of the bottom cover shown in FIG. It is a figure which combines and shows the measurement result of the frequency of the bottle type can by the internal pressure test | inspection apparatus which concerns on this invention, and the measurement result of the frequency of the bottle type can by the so-called sound type tester. It is a figure for demonstrating the other example of a structure of the internal pressure test | inspection apparatus based on this invention. It is a figure which shows the displacement waveform based on the displacement of the bottom cover detected by the laser Doppler sensor. It is the figure which carried out FFT conversion of the displacement waveform of the bottom cover shown in FIG.

  The internal pressure inspection device according to the present invention measures the displacement of the lid portion to which the impact force is applied, calculates a displacement waveform based on the measured displacement of the lid portion, calculates the frequency of the displacement waveform, Based on this, it is configured to determine whether the internal pressure of the sealed container is good or bad. The above-described sealed container is a container in which a body part filled with contents is sealed in an airtight state by a lid part. Specifically, a canopy is attached to the upper end part of the trunk part and a bottom lid is attached to the lower end part. The so-called three-piece type container, the so-called two-piece type container with a canopy attached to the upper end of the body part integrally formed with the bottom part, the mouth and neck having the bottom cover attached to the lower end part of the body part and the screw part at the upper end part It may be a bottle-shaped container or the like in which the part is formed integrally and the cap is screwed to the mouth and neck. The material of the sealed container is not particularly limited, and may be aluminum, an alloy thereof, steel, or the like. The internal pressure inspection apparatus according to the present invention can be applied to the internal pressure inspection of metal cans made of these metals. Further, the sealed container may be a negative pressure container whose internal pressure is lower than atmospheric pressure, or a positive pressure container whose internal pressure is higher than atmospheric pressure.

  FIG. 1 shows an example of the configuration of an internal pressure inspection apparatus according to the present invention. The example shown in FIG. 1 is an example in which the internal pressure of the bottle-type can 1 is inspected, and the bottle-type can 1 filled with the contents is placed in an inverted state with its cap 2 on the lower side. It is configured to be installed on the top and to perform an internal pressure inspection while being conveyed in that state. The bottle-shaped can 1 will be described. A bottom lid 5 is attached to one end of the metal barrel 4, that is, the upper end of the barrel 4 in the vertical direction in FIG. 1. The bottom cover 5 is formed in a substantially disk shape, and is attached to the body portion 4 by winding the outer peripheral flange portion 6 around the opening end of the body portion 4. This winding portion is a connecting portion between the body portion 4 and the bottom lid 5.

  An annular groove portion 7 called a counter sink is formed on the inner peripheral side of the flange portion 6 in the bottom cover 5. From the inner peripheral edge of the annular groove portion 7, that is, from the inner peripheral inclined wall 8 in the annular groove portion 7 to the inner peripheral side. The following part is the panel part 9. In the example shown in FIG. 1, the panel portion 9 is formed in a disc shape. In addition, the bottle type can 1 in the example shown in FIG. 1 is configured as a negative pressure container whose internal pressure is lower than atmospheric pressure. Further, the other end of the body 4, that is, the mouth-and-neck part 10 provided with a screw part on the outer peripheral surface is formed on the lower end side of the body 4 in the vertical direction in FIG. It is screwed together.

  The conveyor 3 continuously conveys the bottle-shaped can 1 in an inverted state, and for example, a belt conveyor can be adopted. The conveyance speed can be set as appropriate, and may be a high-speed conveyance of, for example, about 80 m / min. A rotary encoder (not shown) is attached to the driving side or driven side roller or driving motor shaft of the conveyor 3, and the rotary encoder can detect the traveling speed and the traveling position of the conveyor 3. . Therefore, it is comprised so that the bottle-type can 1 on the conveyor 3 can be specified based on the traveling position information.

  Above the conveyor 3, above the pass line (passing position) of the bottom lid 5 in the bottle-shaped can 1 that is placed and conveyed in an inverted state on the conveyor 3, specifically on a plane parallel to the bottom lid 5 The electromagnetic coil 11 is arranged on the side. The electromagnetic coil 11 is configured in the same manner as an electromagnetic coil used in a conventionally known percussion machine, and generates a magnetic force when energized to attract between the electromagnetic coil 11 and the bottom cover 5. It is designed to generate power and repulsion. That is, the bottom cover 5 is vibrated by momentarily applying an impact force or striking force to the bottom cover 5 electromagnetically. As an example, the electromagnetic coil 11 is formed in a ring shape having substantially the same outer diameter as the bottom cover 5, and the conveyor 3 has a central portion of the electromagnetic coil 11, that is, the center of the ring and the center of the bottom cover 5. A bottle-shaped can 1 is placed on the top. As an example, it is preferable to set the distance between the bottom lid 5 and the electromagnetic coil 11 in the bottle-type can 1 to 5 mm to 10 mm. By doing so, the amplitude of the vibration of the bottom cover 5 by the electromagnetic coil 11 can be increased.

  A laser displacement sensor (hereinafter simply referred to as a displacement sensor) 12 corresponding to the displacement sensor in the present invention is disposed above the electromagnetic coil 11. The displacement sensor 12 is configured to irradiate a laser beam toward the bottom lid 5 of the bottle-shaped can 1 being conveyed by the conveyor 3, capture the reflected light, and measure the distance between them. It is a well-known structure. The laser light is repeatedly irradiated at a high speed. Specifically, when the position where the center of the electromagnetic coil 11 and the center of the bottom lid 5 coincide with each other is set as the reference position, the position is about 5 to 10 mm downstream from the reference position in the conveyance direction of the bottle-shaped can 1. ing. Then, a laser pulse is irradiated through the central portion of the cavity in the electromagnetic coil 11 obliquely from the downstream side toward the bottom cover 5 in the transport direction, and the reflected light is captured on the upstream side in the transport direction. ing. By doing so, the distance from the center of the bottom cover 5 to the upstream side from the center of the bottom cover 5 in the transport direction is continuously measured to the positions of a large number of points (multiple points) on the bottom cover 5. Yes.

  A sensor that detects that the bottle-shaped can 1 has reached the internal pressure inspection start position is disposed above the conveyor 3. The sensor is a timing sensor, and may be either a contact type sensor or a non-contact type sensor. In the example shown in FIG. 1, the photoelectric sensor 13 that detects the bottle-shaped can 1 in a non-contact manner is disposed on the side of the region through which the body portion 4 passes, and the light irradiated by the photoelectric sensor 13 is used as the bottle-shaped can 1 When the bottle type can 1 is blocked, it is detected that the bottle-type can 1 has reached the internal pressure test start position, and the detection signal is output to the controller 14 described later. At the same time when the body 4 first blocks the irradiation light of the photoelectric sensor 13, that is, at the same time when the photoelectric sensor 13 detects the bottle-shaped can 1, the electromagnetic coil 11 is energized to In addition, an impact force or a striking force is applied, and a laser pulse is output from the displacement sensor 12 to start measuring the distance from the displacement sensor 12. The position of the bottle-shaped can 1 on the conveyor 3 can be specified by the detection signal of the photoelectric sensor 13 and the detection signal of the rotary encoder.

  The above-described rotary encoder, electromagnetic coil 11, displacement sensor 12, photoelectric sensor 13 and the like (not shown) are connected to the controller 14. The controller 14 is mainly composed of a microcomputer, and outputs control signals to the rotary encoder, the electromagnetic coil 11, the displacement sensor 12, and the photoelectric sensor 13, and receives detection signals from these devices and sensors. It has become. And it is comprised so that it may calculate based on those detection signals, and the quality of the internal pressure of each bottle type can 1 may be judged as it demonstrates below.

  The bottle-type cans 1 to be inspected are continuously placed on the conveyor 3 in the inverted state shown in FIG. 1, and are conveyed by the conveyor 3 with a predetermined interval between the bottle-type cans 1. When the predetermined bottle-shaped can 1 advances to the installation position of the photoelectric sensor 13, as described above, the bottom cover 5 is vibrated by electromagnetically applying an impact force or striking force to the bottom cover 5 by the electromagnetic coil 11. . At the same time, the displacement sensor 12 outputs a laser pulse to start measuring the distance, and the vibration of the bottom cover 5, that is, the displacement is taken into the controller 14 as distance data. The distance data thus captured is filtered to obtain the displacement waveform of the bottom cover 5. The displacement waveform of the bottom lid 5 is shown in FIG.

  Further, the end of the measurement of the distance data by the displacement sensor 12 can be determined by the passage of time determined from the transport speed by the conveyor 3. Alternatively, the above-described measurement or data capture may be terminated by detecting that the bottle-shaped can 1 has passed the installation position of the photoelectric sensor 13. For example, when the inner diameter of the ring-shaped electromagnetic coil 11 in the transport direction is about 10 mm and the bottle-shaped can 1 having an outer diameter of 53 mm is transported at 80 m / min, the distance measurement by the displacement sensor 12 is started. Therefore, the time required for the center of the bottom lid 5 of the bottle-shaped can 1 to pass through the central portion of the electromagnetic coil 11 is about 5 msec. Therefore, the distance is measured by the displacement sensor 12 for about 20 msec after the bottle-shaped can 1 arrives at the installation position of the photoelectric sensor 13, and when the start of measurement and the timing of punching are simultaneous, the first 10 msec The distance data may be fast Fourier transformed as described below.

  In the above-described example, the measurement start timing of the displacement sensor 12 and the timing of impact application by the electromagnetic coil 11 are configured to be performed at the same time when the bottle-type can 1 arrives at the installation position of the timing sensor. However, the optimum timing varies depending on the speed of the conveyor 3. Therefore, the measurement by the displacement sensor 12 is started at the same time when the bottle-shaped can 1 arrives at the installation position of the timing sensor, and the timing of the impact application by the electromagnetic coil 11 is set to an arbitrary time by the timer from the measurement start timing of the displacement sensor 12. It may be delayed. That is, after an arbitrary time has elapsed from the measurement start timing of the displacement sensor 12, a signal may be sent to the electromagnetic coil 11 to apply an impact to the bottle-type can 1.

  Next, the displacement waveform shown in FIG. 2 is subjected to fast Fourier transform (hereinafter simply referred to as FFT transform) by the FFT analyzer 14 a included in the controller 14. Thus, the frequency of the displacement waveform of the bottom lid 5 is calculated. The frequency obtained by the FFT conversion is shown in FIG. It is determined whether or not the maximum value of the frequency in FIG. 3, that is, the peak is in the frequency band corresponding to the internal pressure of the bottle-type can 1 that is determined to be non-defective. The frequency band is a reference value or threshold value for determining the internal pressure, and is preset by experiment for each type of can and contents to be inspected. If the above-described frequency peak is in the frequency band that serves as the reference for the internal pressure determination, the product is determined to be non-defective. On the other hand, when the frequency peak is not in the frequency band which is the reference for the internal pressure determination, it is determined as a defective product and the bottle-type can 1 to be inspected is a defective product. A signal is output from the controller 14. Thereafter, for example, the bottle-type can 1 determined as a defective product from the transport line by a not-shown exclusion device is excluded.

  Therefore, according to the apparatus having the above-described configuration, the vibration of the bottom cover 5 can be detected by the displacement sensor 12 without using the sound of air vibration, so that the internal pressure inspection accuracy deteriorates due to the resonance phenomenon or the air condition. And the inspection accuracy of the internal pressure of the bottle-type can 1 can be improved. As a result, accurate internal pressure determination can be performed. Moreover, the structure of the apparatus can be simplified as a whole, and the displacement sensor 12 can be easily added to the existing equipment.

  Here, the case where the frequency of the bottle-type can 1 is measured by the internal pressure inspection apparatus having the configuration shown in FIG. 1 and the case where the frequency is measured by a so-called sound percussion instrument will be described. The sound type tester (not shown) applies an impact force to the bottom cover 5 of the bottle-type can 1 to be inspected and inspects the internal pressure based on the frequency of the sound generated by the bottom cover 5. It is a thing of the well-known structure comprised in this way. A plurality of bottle-type cans 1 set to a predetermined internal pressure were prepared, and the frequency of each bottle-type can 1 was measured by an internal pressure inspection device having the configuration shown in FIG. 1 and a conventionally known sound type tester. The measurement results are shown in FIG. The frequency of the bottle-type can 1 measured by the internal pressure inspection apparatus according to the present invention is indicated by “□” in FIG. 4, and the frequency of the bottle-type can 1 measured by the sound type percussion instrument is indicated by “◇” in FIG. It is. In addition, no resonance phenomenon has occurred during measurement by a sound percussion instrument.

  As shown in FIG. 4, the frequency of the bottle-type can 1 measured by the internal pressure inspection device according to the present invention and the frequency of the bottle-type can 1 measured by the sound type tester are related to the internal pressure of the bottle-type can 1. It is recognized that they are consistent with each other. That is, the internal pressure inspection apparatus according to the present invention can obtain an internal pressure inspection accuracy at least equivalent to that of a sound type percussion instrument.

  FIG. 5 shows another example of the configuration of the internal pressure inspection device according to the present invention. The example shown in FIG. 5 is an example in which a laser Doppler sensor (hereinafter simply referred to as “Doppler sensor”) 15 is used instead of the displacement sensor 12. Since the other configuration is the same as the configuration shown in FIG. 1, the same components as those shown in FIG. The Doppler sensor 15 described above is configured to detect the vibration speed of the bottom cover 5 by converting the change in the frequency of reflected light with respect to the frequency of the laser light irradiated toward the bottom cover 5 of the bottle-shaped can 1 into a voltage. It is of a known configuration. In the example shown in FIG. 5, the Doppler sensor 15 is provided at a position above the electromagnetic coil 11 and corresponding to the center of the electromagnetic coil 11. That is, the Doppler sensor 15 is provided at the reference position described above, and when the center of the electromagnetic coil 11 and the center of the bottom cover 5 coincide with each other, the Doppler sensor 15 is positioned on a straight line passing through each center.

  Even in the configuration shown in FIG. 5, similarly to the configuration shown in FIG. 1, when the bottle-shaped can 1 reaches the installation position of the photoelectric sensor 13, the electromagnetic coil 11 electromagnetically applies an impact force or impact force to the bottom lid 5. Is given and the bottom lid 5 is vibrated. At the same time, measurement of the vibration speed of the bottom lid 5 is started by the Doppler sensor 15 and the data is taken into the controller 14. For example, as described above, the vibration speed of the bottom lid 5 is measured for about 20 msec. When the start of measurement and the canning timing are simultaneous, the vibration speed data for the first 10 msec is filtered. By filtering the vibration speed data of the bottom lid 5 obtained by the Doppler sensor 15, a displacement waveform of the vibration speed is obtained. The displacement waveform is shown in FIG. Then, the displacement waveform shown in FIG. 6 is subjected to FFT conversion by the FFT analyzer 14a included in the controller 14, and the frequency is calculated. The frequency obtained by the FFT transform is shown in FIG. As described above, if the frequency peak shown in FIG. 7 is in the frequency band corresponding to the internal pressure of the bottle-type can 1 that is determined to be non-defective, it is determined to be non-defective. Therefore, even when the Doppler sensor 15 is used, the inspection accuracy can be improved because the internal pressure is inspected by detecting the displacement of the bottom lid 5 without using air as in the case of using the displacement sensor 12. Accurate internal pressure determination can be performed.

  The present invention is not limited to the specific examples described above, and the sealed container may be a canned container or a synthetic resin container other than the bottle-shaped can 1 described above. When the synthetic resin container is to be inspected, the synthetic resin container may be vibrated by, for example, a so-called vibration tester instead of the electromagnetic coil 11, and the vibration may be detected by the displacement sensor 12, the Doppler sensor 15, or the like.

  DESCRIPTION OF SYMBOLS 1 ... Bottle type can (sealed container), 4 ... trunk | drum, 5 ... bottom cover (lid part), 11 ... electromagnetic coil (striking part), 12 ... laser displacement sensor, 14 ... controller, 15 ... laser Doppler sensor.

Claims (4)

A sealed container in which at least one of the upper end portion and the lower end portion of the body portion is provided with a lid, a striking force is applied to the lid to generate sound or vibration, and the internal pressure is inspected based on the sound or vibration In the internal pressure inspection device,
A displacement sensor is provided for measuring the displacement of the lid that is applied with the striking force and generates the sound or vibration;
A displacement waveform is obtained based on the displacement of the lid portion measured by the displacement sensor, the frequency of the displacement waveform is calculated, and the quality of the internal pressure is determined based on the frequency. An internal pressure inspection device for sealed containers.   A striking portion for generating the striking force is provided, the striking portion is formed in a shape corresponding to the shape of the lid portion, and the displacement sensor measures the displacement in the center side portion of the lid portion. The internal pressure inspection device for a sealed container according to claim 1, wherein the device is an internal pressure inspection device.   The displacement sensor is at least one of a laser Doppler sensor configured to detect a vibration speed of the lid portion and a laser displacement sensor configured to detect a distance between the lid portion and the laser displacement sensor. The internal pressure inspection device for a sealed container according to claim 1, wherein the device is an internal pressure inspection device.   The internal pressure inspection of the sealed container according to claim 2, wherein the striking part and the displacement sensor are provided so as to be movable relative to the lid part in a direction along a plane parallel to the lid part. apparatus.

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