JPS58193237A - Method of detecting defective sealing - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for detecting a seal failure in a melt-bonded seal portion of a packaged product or the like.

For example, in a retort pouch filling machine that handles ready-made bags that are sealed on three sides, after filling the bag with the required filling material, one of the three sides is sealed to perform airtight packaging of the filling material. In the sealing process, sealing failures may occur due to staining of the sealing surface due to liquid splashing during filling or adhesion of water droplets due to vapor of the filling material. This seal failure can lead to rotting of the filled contents or contamination of the surrounding area, so inspection of the seal surface is irreversible, but as it currently relies on manual visual inspection, it is difficult to increase capacity and save labor in the process. be.

The present invention has been proposed in view of the above-mentioned points, and its purpose is to provide a seal failure detection method that can efficiently detect seal failures and meet the above requirements.

The present invention is characterized in that after the sealing part is fused and bonded by the sealing device, the sealing part is cooled, and then the presence or absence of the four parts in the sealing part is detected by the detection device to detect the presence or absence of a seal defect. If water droplets, oil droplets, etc. adhere to the sealing part, they will turn into steam and swell due to the heat during sealing, and after the sealing part is melted and bonded, when it is cooled, the steam will return to its original state, and the above bulge will become four parts. Therefore, by detecting this with a detection device, the presence or absence of a seal defect can be automatically and efficiently detected, resulting in a great labor-saving effect.

The present invention will be explained below based on examples.

Figure 1 shows an example of a filled and packaged retort pouch product, and 1 is a retort pouch product.

2 indicates a part that requires sealing after filling, and is a part to be inspected. 2' indicates a seal failure area.

3.4,5. is the pre-sealed part, 6
indicates the filling part (bag part).

FIG. 2 schematically shows the steps of the retort pouch filling machine, and the steps are A, B, C, and D.

It changes to E. Part A is a molded retort pouch (bag)
Part 1 is a step in which part 1 is supplied, and part B is a step in which contents (generally food) are filled. Part 0 is a process in which the filled pouch 1 is sandwiched between heat bars and heat-sealed, and Part D is a process in which the filled pouch 1 is sandwiched between cooling bars 21 and the sealed portion is cooled. Part E is a process in which completed retort pouch products are discharged.

FIG. 3 is a sectional view taken along the line XX in FIG. 1, showing the seal portion 2 properly sealed. The surface 7a of the bag is usually coated with polyethylene terephthalate. 7 is an aluminum foil, and 8 is a coating portion on the inner surface of the aluminum foil 7, which is usually coated with polyethylene or polypropylene and is melt-bonded.

FIG. 4 is a sectional view taken along the line X-X in FIG. 1, and shows the state immediately after heat sealing in which a sealing failure has occurred in the seal part 2 due to water droplets or oil droplets during filling. Inflate the seal portion 2 as shown.

FIG. 5 is a sectional view taken along the line X-X in FIG. 1, and shows the state of the defective seal portion 2' after the seal portion 2 has been cooled by the cooling bar 21. The seal portion 2' has been cooled by the vapor during heat sealing and has returned to its original state as shown in the figure. becomes a water droplet, its volume is compressed and it forms an enclosure.

FIGS. 6 to 8 each show an embodiment of a detection device for detecting the presence or absence of a seal defect.

The apparatus shown in Figure 6 uses a television camera.

It detects the brightness and darkness of the shadow on the surface of the seal part 2 by photographing it with an imaging device, 9 is an illumination light beam, 10 is a condensing lens,
11 indicates an imaging device.

The device shown in FIG. 7 uses a laser beam to detect the reflection of the laser beam on the surface of the sealing part 2 by photographing it with a photoelectric element, 12 is the laser beam, 13 is a condensing lens, and 14 is a photoelectric element. , and R indicates the scanning direction. Also, the 8th
The device shown in the figure uses an eddy current sensor or an optical fiber sensor to detect the distance from the sensor to the film, 15 indicates the eddy current sensor or optical fiber sensor, and S indicates the direction of movement of the bag. There is.

Poor sealing of retort pouches results from water droplets, oil droplets, etc. adhering to the sealing area, which causes sealing failure during heat sealing and also creates cavities in this area.

According to the test results, as shown in FIGS. 3 to 5, the coating peels off during heat sealing to form a cavity in the 8 coated area required to seal the water droplet area. This situation is shown in FIG. At this time, due to the heat of the heat seal, the water droplets inside turn into steam and create a bulge, and this bulge is compressed during the process, and as it is cooled, it becomes the original water droplet, and after cooling, this bulge changes into four parts. A seal failure can be detected by detecting these four parts using a detection device as shown in FIGS. 6 and 7.

The system shown in Fig. 6 creates a shadow on the four defective seal parts 2' by illuminating the seal surface obliquely as shown in the figure, and converts the brightness and darkness caused by the shadow into an electrical signal by scanning with a television camera and detects it. This is an example of something that can be done.

Moreover, what is shown in FIG. 7 is an example of a device in which the laser beam is scanned by a rotating mirror or the like (1-) and the reflection of light from the plane portion and the four portions 2' is detected by the photoelectric element 14.

Roughly speaking, what is shown in Fig. 8 converts this defective seal part 2' into an electrical signal using an eddy current displacement meter or an optical fiber displacement meter sensor used in a minute displacement meter. This is an example of what we are trying to detect.

S indicates the direction of movement of the pouch (bag) l, and by this movement, the entire area to be inspected can be scanned. Also.

This can also be achieved using a stylus method similar to a record needle.

As described in detail in the following 1-2 embodiments, the conventional method.

Automatic detection of seal defects, which were difficult to detect, is now possible.
Inspections that used to be inefficient can now be made more efficient, and inspection capacity can be greatly increased.

Note that these methods can be used in similar packaging machines.

[Brief explanation of the drawing]

Figure 1 is a perspective view showing an example of a retort pouch product;
The figure is a process diagram of a retort pouch filling machine, Figures 3 to 5 are equivalent views of the X-X cross section in Figure 1, Figure 3 is a diagram showing a normally sealed state, and Figure 4 is a seal Figure 5 is a diagram showing the state immediately after heat sealing where a defect has occurred; Figure 5 is a diagram showing the state of the defective seal after cooling; Figures 6 to 8 are
The figures are schematic configuration diagrams showing different embodiments of detection devices. 1: Retort pouch, 2: Seal part, 2': Bad seal part, 9: Illumination, 10: Condensing lens, 11: Imaging device, 12: Laser beam, 13: Condensing lens. 14: Photoelectric element, 15: Eddy current sensor or optical fiber sensor, 20: Heat bar 121: Cooling bar Fig. 3, Fig. 4, 2'? ? Figure 5 Figure 6 Figure 7

Claims (1)

[Claims] After 2, the sealing part is melted and bonded using a sealing device. A method for detecting a seal failure, comprising: cooling the seal part, and then detecting the presence or absence of four parts in the seal part using a detection device to detect the presence or absence of a seal failure.