JPS63186141A - Inspecting method for package contents using ultrasonic wave - Google Patents

Abstract

PURPOSE:To accurately detect whether or not contents are affected by bringing an ultrasonic probe into contact with one external surface of a package body which contains the contents and sending an ultrasonic wave, and deciding a detected value. CONSTITUTION:The clamping interval of the package body is made constant, and the ultrasonic probe which contacts one external surface of the package body sends an ultrasonic wave of certain frequency and also receives a reflected wave which is reflected by the other surface of the package body or a reflecting plate provided outside the surface. Here, if the contents are affected, the specific gravity or viscosity varies, so the affected contents and unaffected contents differ in the scattering, diffu sion, and absorption of the ultrasonic wave, so that the detected value of the difference in acoustic speed between a sent wave and a received wave, the acoustic wave of the received wave, the time from the transmission to the reception, or the attenuation speed of ultrasonic wave energy is different. For the purpose, several frequencies are selected as the frequency of the ultrasonic wave to be sent and the best frequency and detection items to be detected are found according to the purpose of he inspection of this package body, thereby accurately deciding whether or not the contents are affected.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an inspection method for determining the presence or absence and degree of deterioration of the contents of a package using ultrasonic waves.

Conventional technology To check for deterioration of the contents such as food filled in a bag, if the contents emit gas when they degenerate and putrefy, the bag expands due to the generated gas, so visually check for expansion. This can be easily determined by observation.

If the contents deteriorate and putrefy without producing gas, if the bag is transparent, the presence or absence of deterioration can be determined by visually observing the contents through the bag. On the other hand, if the bag cannot be seen through, sample an appropriate number and tear the bag.
A method of visually observing the contents is adopted.

Problems to be Solved by the Invention However, although it is possible to visually observe the presence or absence of expansion of the bag when the decomposition has progressed to a considerable extent, it is difficult to check when the amount of gas is low in the early to middle stages of decomposition. It was not appropriate as a means of checking for this, and it could not be determined that deterioration and rot had not occurred just because the bag had not expanded.

Even with the method of visually inspecting the contents through a see-through bag, if the degree of deterioration is not very advanced, it is often impossible to determine the presence or absence of deterioration without destroying the bag.

In addition, in recent food products, laminated products made of aluminum foil are often used as the bag material to improve shelf life, but in this case, the bag-breaking method described above must be used. I had no choice.

However, the inspection method in which a certain number of bags are sampled and then broken has the major disadvantage of requiring a large amount of man-hours for inspection, and even if the sampled items are good, they are lost due to broken bags. Therefore, there was a problem in that there was a lot of waste in terms of cost. In addition, in order to ensure that the inspection is complete, the number of samples must be increased as much as possible, but there is a natural limit to the number of samples, and it is impossible to check all the samples, so there is a limit to reliability.

Also, even if the bag is made of a transparent material and the contents can be seen through, or if the bag is made of a material that cannot be seen through and the contents can be seen by tearing it open,
Depending on the visual inspection, the deterioration may not be clear in some cases, and it is not possible to eliminate the individual differences among the people conducting the test, and there is also the problem that checking for the presence or absence of deterioration is not always accurate.

SUMMARY OF THE INVENTION An object of the present invention is to provide a suitable method that can accurately determine the presence or absence and degree of deterioration of the packed contents without destroying the package.

Means for Solving the Problems The method of inspecting the contents of a package using ultrasound according to the present invention includes transmitting ultrasonic waves by bringing an ultrasonic probe into contact with one outer surface of the package filled with the contents. At the same time, the reflected wave is received, and the existence and degree of deterioration of the contents is determined based on the detected value at that time.

The present invention will be explained in detail below.

Packaging materials that make up the package include single-layer or multi-layer plastic packaging materials, metal, laminates of metal foil and plastics, metallized films, paper, laminates of paper and plastics, and cloth. with resin coating,
All materials such as leather are used. Examples of the packaging material include bags, tubes, and containers.

The contents filled in packaging materials made of such materials include foods, medicines, feed, and the like. The form of the contents may be arbitrary, such as liquid, paste, cream, cake, or powder.

It may be in the form of a solid-liquid mixture or a solid, but if the solid is unevenly distributed inside the package, there will be large variations in measurement. method can be applied effectively. Liquid foods are particularly important.

In the present invention, an ultrasonic probe is brought into contact with one outer surface of a package filled with contents to transmit ultrasonic waves and receive reflected waves.

Normally, the same ultrasonic probe is used to transmit and receive reflected waves, but the transmitter and receiver ultrasound probes may be provided separately (however, both transmit and receive on one external surface).

By transmitting ultrasonic waves and receiving reflected waves, detected values such as ■ the difference in the sound speed of the transmitted wave and the received wave or the sound speed of the received wave, (time from multiple transmissions to reception, ■ degree of attenuation of ultrasonic energy, etc.) can be determined. Therefore, in the present invention, the presence or absence and degree of deterioration of the contents are determined based on at least one of these detected values.

The wavelength range of the ultrasonic waves used is from around 0.5 MHz to 2.
Approximately 0 to Hz is appropriate.

During measurement, it is possible to make a determination using only a single frequency, but the accuracy of the determination can be improved by selecting multiple frequencies of the ultrasonic waves to determine the presence and degree of deterioration of the contents. will be further improved.

FIG. 1 is a block diagram showing an example of the inspection method of the present invention.

(1) is a package, and the contents are filled and sealed inside the packaging material.

(2) is an ultrasonic probe that is in contact with one outer surface of the package (1).

(3) is Magnescale, (4) is length measurement converter, (5)
(6) is a propagation attenuation detection circuit, (7) is a propagation time detection circuit, (8) is an arithmetic circuit, and (9) is a display circuit. Data is output from the white arrow (10).

Function The package is held at a constant interval, and an ultrasonic probe of a certain frequency is emitted from an ultrasonic probe that is in contact with one outer surface of the package, and an ultrasonic probe of a certain frequency is emitted from the Receives the reflected waves that hit the reflector and bounce back.

When the contents change in quality, the specific gravity changes and the viscosity changes, so the scattering, diffusion, and absorption of ultrasonic waves are different between the unaltered contents and the changed contents, and as a result, the difference between the transmitted wave and the received wave is different. Detected values such as the difference in sound speed or the sound speed of the received wave, the time from transmission to reception, and the degree of attenuation of ultrasonic energy are different.

The accuracy of one judgment can be increased by selecting several frequencies of the ultrasonic waves to be emitted in advance and finding the optimum frequency and detection items to be measured that match the purpose of inspecting the package.

Example Next, the present invention will be further explained with reference to Examples.

Example 1 From the outermost layer to the innermost layer: 12 gm thick polyester film lid μm thick aluminum foil/15 p-l1
200g of liquid food (potage soup) is filled inside a packaging bag made from a 4-layer laminated film consisting of a 1-thick biaxially stretched nylon film and a 70-lm thick polyethylene film. The thickness was set to 30 mm.

Immediately after filling this package, the specific gravity was 1.06, the viscosity was 50 cps, and the pH value was 6.7. (Hereinafter referred to as non-deteriorated products) The filled packages were left under the following conditions to produce products with various degrees of deterioration.

Initial deterioration product: After filling, leave at room temperature for 2 to 3 days.Medium deterioration product:
After filling, leave at room temperature for 5 to 8 days Late deterioration product: After filling, leave at room temperature for 10 to 15 days. When the filled package was left at 40°C for two weeks, the specific gravity was 1.06, the viscosity was 1500 cps, the pH value was 5.4, and the contents were yogurt-like. (Hereinafter referred to as "terminal deterioration products") Hold the above five types of packaging horizontally, shake it well, then turn it vertically, and place an ultrasonic probe on one outer surface and a metal reflector that also serves as a support plate on the other outer surface. were brought into contact with each other to maintain the distance between the probe and the reflector at 25 mm.

I MHz and 5 MHz from the ultrasound probe, respectively.
We transmitted an ultrasonic wave with a frequency of , received the reflected wave, and measured the speed of sound, the time from emission to reception, and the degree of attenuation of the ultrasonic energy.

The results were as follows. The test was conducted on 10 packages each.

Test results! i and l l MHz Unaltered product 1670±2 tn/s
ea Early altered product 1674±2 m/sec Middle altered product 1677±2 m/see Late altered product 168
0±2 m1sec (the speed of sound is 1683±2 m1s)
ec) 5 MHz Unaltered product 1671±2 m
1sec early altered product 1672±2 m/sec middle altered product 167B±2 m/see late altered product
1678±2ffl/5ec (outgoing sound speed is 1683±
2 m/5ec) From tongue to AI MHz Unaltered product 39.aEi±0.02
sec Early altered product 39.50±0.02 sec Middle altered product 39.57±0.02 sec Late altered product 3
9.60±0.025ec5 MHz Non-altered product
39.50±0.02 sec Initial deterioration product 39.53
±0.02 sec Medium-term deterioration product 39.58±0.02
sec Late-degraded product 39.84±0.02 sec Seikouto l MHz Non-degraded product -24,4±0.3 d
B Initial deformation amount -20,3±0.3 dB Mid-term deterioration product -7,5±0.3 dB Late deterioration product -4,3±
0.3 dB Lately deteriorated product -3,5±0.3' dB
5 MHz Non-altered product -25.4±0.3 d
B Initial deterioration product -18,5±0.3 dB Medium deterioration product -7,8±0.3 dB Late deterioration product -4,0±
0.3 dB Lately deteriorated product -2.0±0.3 dB From the above results, if you know the sound speed of the reflected wave, the time from transmission to reception, or the degree of attenuation of ultrasonic energy, you can determine the degree of deterioration of the contents. can be determined, and in the above example of potage soup, it can be seen that measuring the degree of attenuation of reflected waves is particularly effective. .

Although specific examples have been omitted, when experiments similar to the above were conducted with various changes in the configuration of the packaging material and various types of liquid food as contents, the presence or absence of deterioration of the contents,
The degree can be determined.

Effects of the Invention According to the method of the present invention, excellent effects as listed below can be achieved.

■ When the contents deteriorate and putrefy, a 1 judgment can be made regardless of whether gas is generated or not.

■ Since the package is not destroyed, it is possible to accurately determine whether or not the contents have deteriorated, and there is no loss due to inspection.

■ Not only the presence or absence of alteration, but also the degree of alteration can be determined.

■ Judgment accuracy is good regardless of the composition of the packaging material used or the type of contents.

・Shadow Depending on the type of contents, this is more accurate than visual inspection, so you can check for deterioration that may be missed by visual inspection.

■ Rapid judgment is possible.

■ In addition to checking the sampled packages, it is also possible to check the entire quantity online, making the inspection highly reliable.

, α There are no individual differences among examiners.

・■ It is advantageous in terms of labor costs as the cost burden of equipment installation is small and the number of man-hours required for the inspector can be significantly reduced compared to visual inspection.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an example of the inspection method of the present invention. (1) Packaging, (2) Ultrasonic probe, (3
)...Magnescale, (4)...Length measurement converter, (
5)...Transmission/reception circuit, (6)...Propagation attenuation detection circuit, (7)...Propagation time detection circuit, (8)...Arithmetic circuit, (9)...Display circuit, (10)... )...White arrow patent applicant Fujimori Industries Co., Ltd. Figure 1

Claims (1)

[Claims] 1. An ultrasonic probe is brought into contact with one outer surface of a package filled with contents to emit ultrasonic waves and receive reflected waves, and based on the detected value at that time. A method for inspecting the contents of a package using ultrasonic waves, the method comprising: determining the presence or absence and degree of deterioration of the contents. 2. The detected value is at least one of the difference in the sound speed of the transmitted wave and the received wave, the sound speed of the received wave, the time from transmission to reception, or the degree of attenuation of ultrasonic energy. Test method. 3. The testing method according to claim 1, wherein the package is a bag. 4. The testing method according to claim 1, wherein the content is a liquid food.