JPH0238835A - Method and apparatus for inspecting airtightness leakage of package - Google Patents

Abstract

PURPOSE:To inspect leakage rapidly and certainly by partially compressing a hermetically closed deformable package and detecting the wave motion generated when the compressed gas in the package is leaked. CONSTITUTION:At first, a package is compressed by a compressor 1 and the compression signal from a compression signal generation circuit 2 is generated in the compressor 1. When airtightness leakage is present, an ultrasonic wave is detected by an ultrasonic sensor 3 on the basis of the unstable flow of the gas generated in the package. The output signal from the sensor 3 is processed by a processing circuit 4 to perform amplification and waveform shaping. Thereafter, the AND with the window signal synchronous to the compression signal is taken and a detection signal is outputted to a judge circuit 5. The signal is compared with a definite reference in the circuit 5 and, when said signal falls below a definite reference value, it is judged that there is no leakage and, when exceeds said reference value, leakage is judged to be present.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a method and apparatus for airtight leakage testing of packaging bodies.
More specifically, the present invention relates to a method and apparatus for testing the airtightness of a package such as a sealed deformable container or bag.

<Prior art and problems to be solved by the invention> A paper container or paper bag for storing milk, alcoholic beverages, etc. is filled with liquid leaving a small amount of air inside, and the spout is sealed and sealed. ing. Furthermore, aluminum foil bags and the like for storing foodstuffs and the like are also sealed on the inside with a seal on the opening.

By the way, if the seal at the time of sealing is insufficient, the airtightness of the containers and bags (hereinafter referred to as "packages") will not be maintained.
This may cause accidents such as liquid leakage or moisture absorption of the contents. Therefore, conventionally, after a certain period of time has elapsed after sealing, quality control has been performed by directly visual inspection or by visual inspection while submerged in water.

However, the manual airtight leakage inspection described above relies on visual inspection, so there is a problem in that it becomes difficult to detect if the seal is slightly open or if there are minute tears or scratches. Furthermore, since it takes time and effort to inspect each package, there is also the problem that inspection efficiency is reduced.

Therefore, it is desirable to mechanically and automatically inspect the package.

Generally, in order to investigate cracks [1] and pinholes formed in solid materials such as vibrators, a method is known in which a pressure difference is created between the inside and outside and the ultrasonic waves generated when fluid leaks are detected. According to this, defects in the vibrator or the like can be inspected by detecting ultrasonic waves. However, when this method is applied to hermetic leakage inspection of sealed packages, the problem is how to create a pressure difference.

Therefore, the package is placed in a vacuum case, the inside of the vacuum case is suctioned by a vacuum pump to reduce the pressure inside, and an ultrasonic sensor attached to the vacuum case detects the ultrasonic waves generated from the package through pinholes, etc. A method has been proposed, and an inspection device using this method has been commercialized.

This makes it possible to inspect sealed packages for airtightness, but it is difficult to maintain complete airtightness of the vacuum case, and ultrasonic waves are generated due to air flowing in through the gaps in the vacuum case. There is a risk of false detection. In addition, since a vacuum pump and vacuum case are required, the equipment is large and
It becomes complicated and expensive. Furthermore, since it takes a lot of time to inspect each product, it is not suitable for continuous inspection of large quantities of packages.

The present invention has been made in view of the above-mentioned problems, and provides a method and apparatus for testing airtight leakage of a package, which quickly and reliably tests a sealed deformable package for airtight leakage and contributes to labor saving. The purpose is to

Means for Solving the Problems> In order to achieve the above object, the airtight leakage inspection method for a package according to the present invention partially compresses a sealed deformable package from the outside, and This is a method of inspecting airtightness of a package by detecting waves generated due to leakage of gas existing inside the package when the airtightness is poor.

Furthermore, the airtight leakage testing device for a package according to the present invention includes a compression means for compressing a part of the package from the outside, and a wave detection means for detecting waves generated when gas existing inside the package leaks. , signal processing and determination means for processing the detection signal from the wave detection means and determining the presence or absence of airtight leakage.

According to the airtight leakage inspection method configured with S above, when the package is partially compressed from the outside, the package is deformed by this,
Pressure inside the package increases. When the airtightness of the package is poor, the gas remaining inside the package is compressed and flows out from the leakage part, and the unstable flow at this time causes waves. The waves are transmitted through the air or through the package or a solid that has come into contact with the package, and are transmitted to the wave detection means. By detecting this, it is possible to inspect the package for airtight leakage.

Further, according to the airtight leakage inspection device of the present invention, a part of the package is compressed by the compression means, waves generated at the time of gas leakage are detected by the wave detection means, the detection signal is processed, and the airtightness leakage is detected. Since the presence or absence of the air can be determined, the airtightness of the package can be quickly and easily inspected.

<Example> Next, an example of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic block diagram showing the basic configuration of an airtight leakage testing device for packages. The airtight leakage inspection device includes a compressor (1) that compresses a deformable package, a compression signal generation circuit (2) that generates a compression signal to the compressor (1), and a compressor (2) that compresses a deformable package when there is an airtightness leakage. An ultrasonic sensor (3) that detects ultrasonic waves generated by the unstable flow of gas inside the package, a processing circuit (4) that processes the output signal from the ultrasonic sensor (3), and an airtight leakage sensor. and a determination circuit (5) that determines the presence or absence of.

Fig. 2 is a flowchart, in which the package is compressed in step (2) and the generated ultrasonic waves are transmitted to the ultrasonic sensor (3).
), the processing circuit (4) performs signal processing (step -), and the determination circuit (5) determines whether there is an airtight leak based on the processed signal (step -). Based on this determination result, it is determined whether the test passes (step ■) or fails the test (step ■).

More specifically, using a timing chart (see FIG. 3), the compression in step (2) above is performed by a compression signal generated from a compression signal generation circuit (2), as shown in FIG. 3(a). Ultrasonic waves are generated immediately after compression and gradually attenuate. The received ultrasonic detection signal is shown in FIG. 3(b). The ultrasonic detection signal is amplified and waveform-shaped within the processing circuit (4) (FIG. 3(C)). After that, the compressed signal is ANDed with the synchronized wind signal (FIG. 3(d)), and the detection signal (FIG. 3(e)) is determined by the determination circuit (5).
) is output. The detection signal is compared with a certain reference value in the determination circuit (5), and if it falls below the certain reference value, it is determined that there is no leakage, and if it exceeds the certain reference value, it is determined that there is leakage.

As described above, the airtightness of the package can be tested by detecting the ultrasonic waves generated from the compressed gas inside the package.

In the above embodiments, the package only needs to be deformable; for example, the package may be wrapped with paper or aluminum foil, and the inner surface may be laminated with a polyethylene sheet, or it may be made only of paper or aluminum foil. It may be something that has been done. Alternatively, the package may be filled with liquid and the ultrasonic waves generated from the gas remaining inside may be detected.
The inside of the package may be filled only with gas. That is, in order to generate ultrasonic waves, the contents of the package may be a mixture of liquid and gas, or only gas.

In addition, it is sufficient to compress only a part of the package, and there is no need to compress the entire package. method, which would be troublesome to implement).

Further, the ultrasonic sensor (3) may be placed in contact with the package or a solid that is in contact with the package (for example, the compression mold itself), or may be placed in a non-contact manner with the package. In the former case, the ultrasonic sensor (3) directly measures the ultrasonic waves propagating through the solid, and in the latter case, the ultrasonic waves are measured via an air medium. It is assumed that a sound wave is generated instead of the above-mentioned ultrasonic wave, but in this case, an audio microphone may be used instead of the ultrasonic sensor (3).

Next, a description will be given of an airtight leakage testing device that compresses paper packs sequentially conveyed by a conveyor one by one using a compression solenoid and automatically tests for airtightness leakage.

FIG. 4 is a plan view, and the paper pack (11) is placed on the conveyor (12) with the sealing opening facing upward. An airtight leakage inspection device is placed in the middle of the conveyor (12), and the entire inspection device can be inspected as needed.
It is surrounded by sound insulation N (13) that insulates external noise. (19) is a satsui window mounted on the wall of the soundproof box (13). The airtight leakage inspection device uses paper packs (+
A compression solenoid (16) is provided to compress the paper pack (11) from the side, and an ultrasonic sensor (15) is provided above the paper pack (11) compressed by the compression solenoid (1B). The amount of compression by the compression solenoid (IG) is set so that the internal pressure can be increased to generate the ultrasonic waves necessary for inspection. (14) is a guide that accurately guides the paper pack (11) to the compressed position. On the downstream side,
The Gion bag (11) that failed the inspection was sent to the defective goods storage area (
1B) is provided with an exclusion solenoid (17). Note that, similar to the configuration shown in Figure 1, a compression solenoid (16
) is connected to a compression signal generation circuit, and the ultrasonic sensor (15) is connected to a processing circuit and a determination circuit, but these are not shown in this figure.

In the airtight leakage inspection device shown in Fig. 4 above, when the conveyor (12) is driven and the paper pack (11) is conveyed to the compression position, the compression solenoid (IG) operates to press the side surface of the paper pack (11). Compress. Paper pack (1
1) is pressurized and the air collected at the top of the paper pack (11) leaks to generate ultrasonic waves, which are collected by the ultrasonic sensor (15).

The detection signal from the ultrasonic sensor (15) is processed,
If the signal value exceeds the standard value, wait until the paper pack (11) is transported to the position of the exclusion solenoid (17), and then be pushed out to the defective product storage area (18) by the exclusion solenoid (17). . If the signal value does not exceed the reference value, it is transported as is.

As described above, this airtight leakage testing device can inspect a large number of paper packs (11) in a short time by simply compressing the side surfaces of the paper packs (11), and moreover, it is possible to inspect a large number of paper packs (11) by simply compressing the sides of the paper packs (11). and rejected products can be automatically sorted. Therefore, it is suitable for continuous automatic inspection processing in an automated filling factory.

In the above case, the paper pack (11) is placed upright and the top of the paper pack (11) is filled with gas. However, if you want to check for leakage from the bottom of the paper pack (11), In this case, the same test can be performed by holding the paper pack (11) upside down. Moreover, if it is desired to inspect the side surface, the paper pack (11) can be laid down on its side.

FIG. 5 shows an example of compression by a robot hand, and the same members as in FIG. 5 are given the same reference numerals. According to this example, the paper bag (11) on the conveyor (12) is picked up by the robot hand (21), and the ultrasonic sensor (
15) and compress the sides of the paper pack (11) with the grip force of the robot hand (21) to generate ultrasonic waves. If sound insulation is required, connect the upper and side parts of the robot hand (21) to the body of the sound insulation box (
13a), and the robot hand (2
The lower part of 1) may be surrounded by a removable sound insulating lid (13b). This allows the sound insulating lid (
13b) is closed so that surrounding noise can be insulated, and the sound insulation M (tab) is opened before and after the ultrasonic AWL is determined, so that the lifting and lowering of the robot hand (21) is not obstructed.

In the embodiments shown in FIGS. 4 and 5 above, the ultrasonic sensor (15) is a non-contact type ultrasonic sensor that detects ultrasonic waves propagating in the air; A sensor may also be used. Contact type ultrasonic sensor (Fig. 4 (15a)
), see Figure 5 (15a)), for example, to the push rod of the compression solenoid (16) or the arm of the robot hand (21), it is possible to detect the ultrasonic waves generated from the pinhole and transmitted through the solid. can do.

Experimental Example: In a laboratory, a leakage test was conducted on a paper pack using the arrangement shown in Figure 6. The paper pack (31) was emptied of its contents through a plastic cap, filled with air and provided with a pinhole (32).

The paper pack (31) was compressed by placing a weight (33) on it or by pressing it by hand. Pinhole (3
An ultrasonic sensor (34) is installed at a distance from 2), and an ultrasonic sensor (35) for background noise removal is installed side by side with the ultrasonic sensor (34),
(35) was connected to the signal processing circuit (37). (34a
).

(35a) is a sound collection horn attached to both sensors (34) and (35). The output signal of the signal processing circuit (37) was recorded on a chart by supplying it to a recorder (38).

On the other hand, in order to investigate the effect of noise, an ultrasonic sensor (34
) A disc grinder (3
9) was placed to generate noise from time to time.

The results of the test are shown in FIGS. 7 to 9.

FIGS. 7(a) to (c) show the waveforms of measurement signals when Δ11 is determined by the ultrasonic sensor (34) alone in a noise-free state, and (a) shows the distance fli L −5 cm and the load. W-1
, 3 to 9, (b) is the distance fIL -5 cm, the load W-5
, 3 to 9, (c) is distance L=lOcms load W-5,3
The results are shown when set to kg.

As is clear from each figure, a signal with a level sufficiently higher than the background noise level is obtained, the signal strength increases as the load W increases, and the signal strength decreases as the distance increases.

FIGS. 8(a) and 8(b) show waveforms of measurement signals at loads W-2 and 31+3 under conditions using ultrasonic sensors (34) and (35). (a) is the distance L=lOc++
+, no noise condition, (b) distance f/i L -10c
rn, noise condition; (b) shows the signal waveform at distance L=5 cm and noise condition.

In the absence of noise, the signal appears clearly, but when noise is applied, the separation between the signal and the noise is slightly reduced (FIG. 8(b)). However, when the ultrasonic sensor (34) is brought closer, the degree of signal separation improves (FIG. 8(C)).

Although measurement results are not shown, when the entire device was surrounded by a sound insulating box, the noise of the disc grinder (39) was reduced by about 6 dB and the clarity of the signal was further improved.

Figure 9 shows the ipl when the paper pack (31) is compressed by hand and measured using the ultrasonic sensor (34) alone in the absence of noise.
The waveform of the constant signal is shown (distance #iL -103).

Since it was compressed by hand, there are many irregularities in the signal waveform, but the presence of the signal can be clearly observed.

From the above experimental results, it was found that it was possible to reliably observe the waves generated when air flows out of the pinhole, and that the signal level increased as the load was increased and the ultrasonic sensor was brought closer. In addition, JFJ can be determined even under noisy conditions, noise can be reduced when used in conjunction with a sensor for background noise removal, it is effective to surround it with a sound insulation box, and iljl can be determined even when compressed manually. found.

<Effects of the Invention> As described above, according to the present invention, the inside of the package can be pressurized by a simple method of only partially compressing the sealed, deformable package.

This can be done by detecting the waves that occur when the compressed gas inside the package leaks, so the inspection can be performed more quickly and reliably than the conventional visual inspection of packages. This has the unique effect of improving inspection efficiency.

[Brief explanation of the drawing]

Fig. 1 is a block configuration diagram showing an embodiment of the airtight leakage testing device for packages according to the present invention, Fig. 2 is a flow chart showing the airtightness leakage testing procedure for packages, Fig. 3 is a signal waveform diagram, and Fig. 4 is A schematic diagram illustrating a device that compresses filter paper bags one by one by a compression solenoid and inspects for airtight leakage as they are conveyed sequentially by a conveyor. Fig. 5 is a schematic diagram showing a device that compresses filter paper bags by a robot hand and inspects for airtightness leakage. , Fig. 6 is a diagram showing an outline of the experimental equipment, and Figs. 7 to 9 are waveform diagrams obtained from the experiment. (1)... Compressor, (3)... Ultrasonic sensor, (4
)... Processing circuit, (5)... Judgment circuit, (11) Paper pack, (15)... Ultrasonic sensor, (lB)...
・Compression solenoid, (21)...Robot hand Figure 1 Patent applicant Nondestructive Inspection Co., Ltd. Figure 2-i8 Figure (e) Tony $ value in the detection signal Figure Figure Figure Figure Diagram: Work ≦ Work

Claims (1)

[Claims] 1. The sealed, deformable package is removed from the outside. The airtightness of the package may be partially compressed due to present inside the above package if Detects waves generated by gas leaks and inspect the package for leakage. A method for inspecting airtight leakage of a package, characterized by: 2. Pressure that compresses a part of the package from the outside Compression means and gas present inside the package Detects the waves generated when leakage occurs. Wave detection means and detection from wave detection means Processes intelligence signals to determine whether there is an airtight leak. and a signal processing determination means for Characteristic packaging airtight leakage inspection device.