JPH03211436A - Method for testing sealability of tubular containers - Google Patents

Abstract

PURPOSE:To inspect the sealing performance of a seal lid in an empty state by sealing a bottom end and deciding the sealing performance according to variation in pressing force while a barrel part is pressed with a constant displacement quantity for a specific time. CONSTITUTION:While the cap of the tubular container is unclamped slightly and the bottom end is sealed with a plug body, the tubular container moves in a direction A together with a moving body and enters the pressing part 10c of a guide body 10. Then the flexible barrel part 4 is recessed by a constant displacement quantity and sectioned in an oval shape to decrease in its internal capacity on the whole, and the state wherein the internal pressure rises is continued while the container moves along the pressing part 10c. Consequently, if the sealing of a seal lid 7 is deficient, the internal pressure drops and the output of a load cell 18 becomes less than the output of a load cell 17. Therefore, the sealing performance of the seal part of a mouth part can be decided from whether or not there is the phenomenon of the pressing force and while the tubular container is empty, the sealing performance of the seal lid 7 can be inspected without contaminating an inspection device nor losing the contents.

Description

[Detailed description of the invention] (Industrial application field) The present invention uses paste-like spices (for example, mustard).

The present invention relates to a method for testing the sealing property of a seal at the mouth of a tube-shaped container mainly for storing liquid contents such as wasabi (Japanese horseradish, ginger, etc.), seasonings, or vegetable oil.

(Prior art) Chicob-shaped container 1 for storing paste-like spices, etc.
1 is usually made of a soft thermoplastic, such as single-layer or multi-layer polyethylene or polyvinyl chloride, and generally has a relatively thick mouth and neck part 2 and a shoulder part 3, which are relatively thick and hard to deform, as shown in FIG. and a relatively thin and flexible body 4, usually cylindrical, with a bottom end 5.
is open (see Fig. 2), and a sealing lid 7 is heat-sealed to the mouth portion 2a of the single-port neck portion 2 (see Fig. 3).
It's getting better.

The sealing lid 7 usually consists of an outer layer of aluminum foil and an inner layer of a hot melt layer (not shown) mainly made of ethylene-vinyl acetate copolymer or the like. To heat seal the seal M7, screw the plastic cap 8 into which the seal lid flank is inserted to the mouth and neck part 2, and
The seal lid 7 is attached to the end surface 2a by the bottom surface 8a of the top plate of the knob 8.
This is done by heating the aluminum foil of the sealing lid 7 by induction using a high-frequency induction heating coil (not shown) in a state of tζ to melt the hot melt layer.

After filling the contents into this tubular container 1 from the open bottom end 5, the bottom end is thermocompressed and heat-sealed with a real plate or the like to form a sealed container (not shown). Finally, after removing the cowshield knob 8 and peeling off the seal lid 7, the body part 4 is pressed with fingers to push out the contents along the mouth and neck part 2.

Since the heat-sealed portion at the bottom end of the above-mentioned sealed container is formed by flattening the cylindrical bottom end and thermo-compression bonding, 1 there is virtually no loss of compatibility during normal work. do not have.

However, when the flat seal lid black is inserted into the cap, the seal M7 has its peripheral edge bent along the outer periphery 2a2 of the mouth portion 2a, forming wrinkles 9, and the seal lid 70 portion on the end surface 2aI. Poor alignment may occur because the cap 8 is easily wrinkled, the positioning device is misaligned, or the pressing force is insufficient due to insufficient screw tightening of the cap 8 or diagonal tightening, etc. .

A method for testing the sealability of this type of container is to momentarily press the body of the container containing the contents and heat-sealing the bottom end.
A method has been devised to measure the thickness of the deformed part after a certain period of time has elapsed after the deformation, and to judge and sort those with a large thickness as good and those with a small thickness as defective (for example, Utility Model No. 54-1999). 75188).

In the case of a poorly sealed container, the contents leak from the container (mainly from the mouth), which tends to contaminate the inspection equipment, and since the poorly sealed container is discarded together with the contents, it is difficult to use this method. However, the problem arises that the contents are lost and the cost increases accordingly.

(Problems to be Solved by the Invention) The present invention is capable of double-sided inspection of the seal lid in an empty state, thus preventing contamination of the inspection device or [ of the contents ].
An object of the present invention is to provide a method for inspecting a tubular container having a flexible body without causing damage.

(Means for Solving the Problems) In the method of testing the sealability of 2g of tube-shaped container according to the present invention, one opening is heated and the bottom end is open. A method for testing the sealing performance of the first opening of an empty tubular container with a flexible body, in which the bottom end is sealed and pressure is applied to the body at a constant displacement for a predetermined period of time. Based on the change in pressure,
It is characterized by determining sealing performance (hereinafter referred to as the first invention).

In another method for testing a tubular container of the present invention, eight openings are heat-sealed and the bottom end is open. In a method for testing the sealing performance of a single-mouth seal of an empty tubular container with a flexible body, the displacement of the body is determined while the bottom end is sealed and a constant pressing force is applied to the body for a predetermined period of time. (hereinafter referred to as the second invention) (Operation) In the case of the first invention, since the bottom end is sealed, the heat-sealed part of the mouth part is sealed. If the sex is perfect.

An empty tubular container is completely sealed with only air inside. In this state, if you press the flexible body and apply a certain amount of displacement to the body (within a range that does not impair the compatibility of the mouth seal due to the increase in internal pressure described later), the internal volume will decrease. Therefore, according to Boyle's law, the internal pressure increases and becomes higher than atmospheric pressure. However, even if this pressing force is maintained for a predetermined period of time (usually about 0.5 to 10 seconds), no change in the pressing force occurs.

If the sealing performance of the mouth seal is incomplete and there is, for example, a pinhole that penetrates the inside and outside, internal air will gradually leak through the pinhole, causing the internal pressure to decrease while pressure is applied. Therefore, the pressing force (repulsive force against internal pressure) required to maintain a constant amount of displacement also decreases.

Therefore, the sealability of the sealing portion of the nine openings is determined by the presence or absence of this pressing force phenomenon. Note that even if a decrease in the pressing force is observed, if it is proven that the degree of decrease is so small as to pose no problem in practical use, it may be determined that the sealing performance has passed.

2. Like the prior art. When the body is filled with liquid content, if there is a pinhole in the sill, when the body is pressed down with a certain amount of displacement, the same amount of content as the reduced internal volume will immediately pop out of the pinhole due to the hydrostatic effect. (often by pushing the pinhole apart). Therefore, in this case, the application of pressure may be instantaneous, but if there is only air in the container, the hydrostatic pressure effect will not work, and the air will gradually flow out through the pinhole, so the change in pressure will be significant. The pressure must be maintained for a predetermined period of time until it is detected.

In the case of the second invention, if the sealing performance of the first seal part is perfect, when a constant pressing force is applied to the flexible body, the body is displaced and the internal pressure increases. However, while a constant pressing force is applied for a predetermined period of time (usually 0.5 to 10 seconds), there is no leakage of internal air, so there is no change in the amount of displacement of the body.

However, if the sealing performance of the mouth seal is incomplete, the internal air will flow out through the binhoher etc. while a certain pressure is applied, and the body will be closed in an amount corresponding to the volume of the air that has flowed out. Since the amount of displacement increases, it is possible to determine the compatibility of the mouth seal portion depending on the presence or absence of this amount of displacement and its degree (Example) FIG. 4 for showing an example of the first invention, In FIG. 5, reference numeral 10 denotes a guide body that presses the body 4 while guiding the tubular container 1 moving at a constant speed in the direction of arrow A. As shown in FIG. of
The pair are parallel as a whole, that is, parallel except for the tapered portion 10b.

It mainly consists of fixed ports 7 doors Ila and llb.

Portion 10a on the upstream side of the tapered portion 10b of the guide body IO
The interval width is equal to or slightly larger than the outer diameter of the body portion 4. On the other hand, the interval width of the portion 10c on the downstream side of the tapered portion 10b is slightly smaller than the outer diameter of the body portion 4, and during the period when the container 1 passes through the portion 10C, the body portion 4 is pressed from both sides. 4, if the sealing performance of the seal lid 7 is ensured, the internal pressure (usually about 1 to 2 kg/
cm"), it is configured to provide a relatively large and constant amount of concave deformation within a range that does not impair its sealing performance. In other words, the portion 10c serves as a pressing portion.

The fixed rod Ilb is separated from the fixed loft Ilb at the upstream end of the pressing portion 10c. In addition, a pressing force measuring element 12 having the same cross-sectional shape as the fixed rod llb is loosely inserted. Pressing part]
A similar pressing force measuring element 13 is also provided at the downstream end of Oc. Shafts 14 and 15 extending perpendicularly to the fixed rod llb are fixed to each pressing force measuring element 12.13, and the other end of the shaft 14.15 is fixed to the fixed frame 1.
It is fixed at 6.

Load cells 17 and 1 are mounted on axes 14 and 15, respectively.
8 is installed. Output signals 17a and I8a of each load cell 17 and 18 are input to a comparator 19. 1
7b is a delay circuit.

Time taken for the tubular container 1 to reach the position of the pressing force measuring element 12 from the position of the pressing force measuring element 13, output signal +7a
is supposed to be delayed. Comparator 19 receives signal 18
It is configured to output a reject signal 20 when the voltage of the signal a is smaller than the voltage of the signal 17a by a certain value or more.

In FIG. 5, 21 is a stopper that seals the bottom end 5 of the tubular container 1. As shown in FIGS. 6 and 7, the plug body 21 is fitted with an elastic rubber ring 22. It is composed of a plurality of split pieces 23a tapering downward, and has a radially movable split mold 23 and a truncated conical shape that engages with the split mold 23,
It consists of a core 24 that can move up and down.

The outer diameter of the elastic rubber ring 22 is set to a size that allows it to be loosely inserted into the bottom end 5 in a normal state, that is, in a state in which the diameter is not expanded as described later, that is, in a contracted state. 22a is a recess 25 of the moving body 25
It is fixed to the movable body 25 within a. core 24
is configured to be moved up and down via a lift shaft 26 by a drive device (not shown). When the core 24 is in the raised position, the elastic rubber ring 22 is in an expanded state and a gap 23b is formed in the split die 23.

When in the lowered position/in the contracted state, each split piece 23a
are in contact with each other so that the gap 23b disappears.

When the core 24 is in the lowered state and the elastic rubber ring 22 is in the normal state, the bottom end 5 of the tubular container l is inserted into the stopper body 21, and then the core 24 is raised to form the 10% mold 2.
3 expands in the radial direction to expand the elastic rubber ring 22, so that the elastic rubber ring 22 comes into close contact with the inner surface of the bottom end 5.
The bottom end 5 is sealed.

27, when the body part 4 is pressed, the internal air flows into each split piece 23.
This is an O-ring to prevent leakage through the gap 23b between spaces 23b and 23a. Each moving body 25 is fixed to a chain (not shown).

A chain driven by a constant speed motor (not shown) moves along the guide bar 28 in the direction of the arrow.
It is configured to move the tubular container 1 in the same direction.

In the above apparatus, one tube-shaped container l is.

With the cap 8 screwed back slightly and the bottom end 5 sealed by the stopper 2I, it moves in the direction of arrow A together with the movable body 25 and enters the pressing portion 10c of the guide body 10. Thereafter, the flexible body 4 is given a certain amount of concave deformation, as shown in FIG. becomes (4th
(see figure), the overall internal volume decreases and the internal pressure increases. This state continues while moving along the pressing portion 10c. That is, the body portion 4 is pressed by a constant amount of displacement for a predetermined period of time.

When the seal lid 7 is completely sealed, there is no change in the internal pressure during this period, so the internal pressures detected at the inlet end and the outlet end of the pressing portion 10c, that is, the outputs of the rod cells 17 and 18, are the same. On the other hand, if the sealing of the seal lid 7 is incomplete, air leaks from the incompletely sealed portion and the internal pressure decreases.

Therefore, the output of the load cell 18 is 6 smaller than the output of the load cell 17. This output difference is detected by a comparator, and when this difference is larger than a predetermined value by experiment or empirical rule, a reject signal is output and the corresponding A sticker mark is attached to the tube-shaped container l.

After the tubular container 1 exits the guide body 10, the core 24 descends, the two elastic rubber rings 22 contract, and the tubular container 1 is removed from the stopper 21.

Cow? After the knob 8 is screwed again, it is transported to the primary process. At that time, the tubular container 1 with the reject mark attached is discarded.

FIG. 8 and FIG. 9 are for showing an embodiment of the second invention. 29 is a displacement measuring element having a shape of a convex lens (the pressing surface is flat and has a shape of 6); 30 is a weight having a constant weight; 31
32 is a weight lifting device, and 32 is a gauge sensor. Lifting equipment 3
1 is always the surface plate 36 at the lower end 29a of the displacement measuring element 29.
The height of the twist is arranged at a position equal to the outer diameter of the body 4. The gauge sensor 32 includes a movable shaft 33 and a sensor head 34, and a contact 33a at the lower end of the movable shaft is configured to constantly contact the upper surface of the weight 30 by a sublinog (not shown).

The amount of vertical displacement of the movable shaft 33 is converted into an electrical output (voltage value) by a sensor mechanism (L9 not shown) provided in the sensor head 34, and this electrical output is sent to a voltage indicator or recorder. Seal W using this device to input
The pairwise test in step 7 is performed as follows.

As shown in FIG. 8, the tubular container 1 with the gyushi whelk slightly rewound and the bottom end 5 sealed with the stopper 21 is placed horizontally on the surface plate 36 via the movable body 25. Then, the zero-order lifting tool 3 brings the displacement measuring element 29 into light contact with the trunk 4.
1 as shown in FIG. Immediately, the weight 3
0 descends and applies a constant pressing force to the center of the body 4 via the displacement measuring element 29. Therefore, the flexible body 4
is depressed vertically and at the same time extends horizontally, increasing internal pressure. After a predetermined period of time has elapsed, the lifting tool 31 is raised to return the single weight 30 to its original position. The amount of concave displacement d of the body portion 4 between C and C is indicated or recorded by the indicator or tc on the recorder 35 via the movable shaft 33 of the gauge sensor 32.

If the sealing of the seal lid 7 is complete, there is no change in the amount of displacement d during the pressing period, but if it is incomplete, the displacement d! d increases gradually. Therefore, the difference Δ between the displacement amount d at the start and end of pressing
If d is larger than a value predetermined by experiment or empirical rule, the tube-shaped container 1 is determined to be a container with poor sealability, and the inspection is conducted with the tube 8 loosened. Stated. Even when the cap 8 is tightened, it is possible to detect sill defects due to defects such as a slanted cap or dents on the end faces of the four parts. However, it is difficult to detect sealing failures due to incomplete adhesion, etc. in the absence of the above-mentioned defects. Therefore, it is preferable to perform the inspection with the cap 8 loosened.

Next, a specific example will be described.

Specific example 1 Height of trunk 4: 12CI11. Outer diameter 23■, wall thickness approximately 0.3
With the bottom end 5 of a multi-layered tubular container l mainly made of low-density polyethylene of 1.5 mm thick sealed with a stopper 21, it is moved at a speed of 5 m/min in the direction of arrow A along the guide lO shown in FIG. As a result, a certain amount of concave deformation was applied to the center part of the body part 4. The maximum thickness reduction amount of the body part 4 due to this concave deformation (Δt1+Δt2; first +Δt16 mm), and the time for the body part 4 to move between the pressing force probes 12 and 13 was 4 seconds.

In the case of the tubular container 1 in which the sealing performance of the seal lid 7 was confirmed, there was no difference in output between the load cells 17 and 18.

In addition, this confirmation is carried out by pressing approximately the center of the body 4 until the thickness decreases by approximately 16 mm while the neck 2 of the tube-shaped container 10 whose bottom end 5 is sealed with the stopper 21 is immersed in water. This pressing was continued for 10 seconds, but it was confirmed that no air bubbles were generated from the sealed portion.

On the other hand, a large number of bubbles were generated by the above-mentioned underwater immersion method.

When a similar test was conducted on the poorly sealed tubular container 1, the force detected by the load cell 17 was 1.2 k.
gf, and the force detected by the load cell 18 was 0.3 kgf.

Concrete Example 2 A cup-shaped container 1 with its bottom end 5 sealed, which is similar to Concrete Example 1, is placed on a surface plate 36 shown in FIG.
Via the displacement measuring element 29 by a weight 30 of 0 kg,
Approximately the center of the side portion 4 was pressed for 4 seconds.

In the case of the tubular container 1 whose sealability was confirmed in the same manner as in Example 1, there was no change in the amount of displacement d, but in the case of the tubular container 1 with poor sealing, the amount of displacement d at the start of pressing was 7
In (2), the displacement d at the end of the pressing was 20 mm.

The present invention is not limited to the above examples, but 1
For example, the fixed lofts Ila, Ilb, the shape and dimensions of the pressing force measuring element 12 or the displacement measuring element 29 may be of any size 6, that is, for example, the fixed loft F l l' a shown by the dashed line in FIG. As shown in FIG. It is more preferable to use the stopper 21 because there is a risk of damage to the plug.

In addition, a constant pressing force may be applied by an air cylinder, and the amount of displacement may be measured by a potentiometer.
good.

(Effects of the Invention) The method for testing a tube-shaped container having a flexible body according to the present invention allows the sealing performance of the seal lid to be tested in an empty state, thereby preventing contamination of the testing device.

Alternatively, there is an effect that there is no risk of loss of contents.

[Brief explanation of drawings]

1 is a front view of an example of a tubular container to which the present invention is applied, FIG. 2 is a bottom view of the tubular container of FIG. 1, and FIG. 3 is a view of the vicinity of the mouth of the tubular container of FIG. 1. Longitudinal sectional view, 4th
The figure is a plan view of a first example of an inspection device for carrying out the present invention, FIG. 5 is a vertical sectional view taken along the v-v line in FIG. 4, and FIG. 6 is a Vl-1rI line in FIG. 5. FIG. 7 is a cross-sectional view taken along the line ■-■ in FIG. 6, and FIGS. 8 and 9 are front views of a second example of the tζth inspection device that implements the present invention. FIG. 8 and FIG. 9 are drawings showing the state immediately before and during pressing, respectively. 1 Tubular container, 2a Mouth part, 4-Body part 5 Bottom end, 7゛Seal lid, 12 - Pressure force measuring tip. 29 Displacement measurement head. boiling diagram

Claims (2)

[Claims] (1) The mouth is heat-sealed and the bottom end is open.
In a sealing test method for the mouth seal of an empty tubular container with a flexible body, the bottom end is sealed and the pressing force is applied while applying pressure to the body with a constant amount of displacement for a predetermined period of time. A method for testing the sealability of a tubular container, the method comprising determining the sealability based on a change in the sealability of a tubular container. (2) The mouth is heat-sealed and the bottom end is open.
In a sealing test method for the mouth seal of an empty tubular container with a flexible body, the displacement of the body while the bottom end is sealed and a constant pressing force is applied to the body for a predetermined period of time. A method for testing the sealability of a tubular container, characterized by determining the sealability based on a change in quantity.