JP7323765B2 - Double container leak inspection method and preliminary peeling method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a leak inspection method and a preliminary peeling method for a double container in which the inner bag shrinks as the contents decrease.

In Patent Literature 1, air is supplied into the inner bag, and the presence or absence of holes in the inner bag is inspected based on whether or not the pressure inside the inner bag reaches a predetermined value after a predetermined period of time has elapsed.

Patent 3303234

In the method of Patent Document 1, if the inner bag unintentionally swells when air is supplied into the inner bag, the inner bag will have a hole even if there is no hole in the inner bag. There is a possibility that it may be determined to exist, and a leak inspection method using another means is desired.

SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances, and provides a leak inspection method capable of detecting the presence of pinholes in the inner bag of a double container.

According to the present invention, there is provided a leak test method for a double container, wherein the double container has an outer shell and an inner bag, and is configured such that the inner bag shrinks as the contents decrease. A method is provided, wherein the method comprises determining whether a pinhole exists in the bladder based on data obtained during depressurization of the interior of the bladder.

Data such as the flow rate of the air sucked out from the inside of the inner bag when the inside of the inner bag is decompressed, the decompression pressure, etc. differ depending on whether or not there are pinholes in the inner bag. Based on this difference, it can be determined whether or not there is a pinhole in the inner bag.

Various embodiments of the present invention are illustrated below. The embodiments shown below can be combined with each other.
Preferably, in the method described above, the determination is performed based on the flow rate of air sucked out from the inner bag during the pressure reduction.
Preferably, in the method described above, the decompression is performed with a rod-shaped portion inserted into the inner bag from the mouth portion of the double container.
Preferably, a method for pre-peeling a double container, wherein the double container has an outer shell and an inner bag, and is configured such that the inner bag shrinks as the contents decrease, is a method comprising the step of peeling the inner bag from the outer shell by depressurizing the interior of the inner bag in a state where the rod-shaped portion is inserted into the inner bag from the mouth of the double container be.
Preferably, in the method described above, where H is the total height of the double container and L is the length of the portion of the rod-shaped portion inserted into the inner bag, L/H is 0. .40 or greater.
Preferably, in the above-described method, D2/D1 is 0.30 or more, where D1 is the diameter of the inscribed circle of the inner peripheral surface of the mouth portion and D2 is the diameter of the circumscribed circle of the rod-shaped portion. , is the method.
Preferably, in the method described above, the pressure reduction is performed through a suction port provided in the rod-shaped portion.
Preferably, in the method described above, the suction port is provided at the tip of the rod-shaped portion.

1 is a perspective view of a double container 1 to be inspected for leaks. FIG. 1 is a block diagram of a leak inspection device 2 according to a first embodiment of the present invention; FIG. FIG. 3 is an exploded perspective view showing the configuration of the head 3 of FIG. 2; 4 is a cross-sectional view showing a state in which the head 3 of FIG. 3 is brought into contact with the end face of the mouth portion 9 of the double container 1. FIG. FIG. 5 is a cross-sectional view showing a state after the inside of the inner bag 14 is evacuated from the state shown in FIG. 4 to contract the inner bag 14; 4 is a graph showing the relationship between time and flow rate measured when the pressure inside the inner bag 14 is reduced. FIG. 5 is an exploded perspective view showing the configuration of a head 3 of a leak inspection device 2 according to a second embodiment of the present invention; 8 is a cross-sectional view showing a state in which the head 3 of FIG. 7 is brought into contact with the end surface of the mouth portion 9 of the double container 1. FIG. FIG. 9 is a cross-sectional view showing a state after the inside of the inner bag 14 is decompressed from the state of FIG. 8 to contract the inner bag 14; 6 is a cross-sectional view corresponding to FIG. 5 when the inner bag 14 is partially peeled off; FIG. 6 is a cross-sectional view showing a state in which the bottom portion 14a of the inner bag 14 is lifted up when the pressure inside the inner bag 14 is further reduced from the state of FIG. 5. FIG.

Embodiments of the present invention will be described below. Various features shown in the embodiments shown below can be combined with each other. In addition, the invention is established independently for each feature.

1. First Embodiment A leak inspection method for a double container according to a first embodiment of the present invention will be described.

<Double container 1>
First, the double container 1 to be inspected for leakage will be described with reference to FIGS. 1, 4 and 5. FIG. The double container 1 is a so-called delaminating container having an outer shell 12 and an inner bag 14, and the inner bag 14 shrinks as the contents decrease. As the inner bag 14 separates from the outer shell 12 as the content decreases, the inner bag 14 contracts away from the outer shell 12 . In such a container, outside air is less likely to enter the inner bag 14, so deterioration of the contents is suppressed.

The outer shell 12 is made of, for example, low density polyethylene, linear low density polyethylene, high density polyethylene, polypropylene, ethylene-propylene copolymers and mixtures thereof. The outer shell 12 may have a multilayer structure. The inner bag 14 is preferably constructed from multiple layers. For example, an EVOH layer made of ethylene-vinyl alcohol copolymer (EVOH) resin is used for the layer in contact with the outer shell 12, and the layer in contact with the contents is, for example, low density polyethylene, linear low density polyethylene, high An inner layer comprising polyolefins such as density polyethylene, polypropylene, ethylene-propylene copolymers and mixtures thereof can be used. An adhesive layer is preferably used between the EVOH layer and the inner surface layer.

The double container 1 has a cylindrical shape with a bottom, and includes a storage portion 7 for storing contents and a mouth portion 9 for discharging the contents from the storage portion 7 . The housing portion 7 includes a trunk portion 7a and a bottom portion 7b. The mouth portion 9 is provided with an engaging portion (male screw portion) 9d so that a cap or a pump can be attached.

When the double container 1 is formed by direct blow molding, the double container 1 has cut portions 7d formed by crushing a parison with a pair of split molds. The cutout portion 7d is provided in the bottom portion 7b of the double container 1, and the bottom of the double container 1 is closed by welding the facing surfaces of the parison at the cutout portion 7d. The cutout portion 7d closes the bottoms of the outer shell 12 and the inner bag 14, respectively. The outside air introduction portion 15 can be formed by opening the cut portion 7d. Outside air can be introduced between the outer shell 12 and the inner bag 14 through the outside air introduction part 15 . When the external air introduction portion 15 is formed in the cut portion 7d, the bottom portion of the inner bag 14 is hardly fixed to the bottom portion 7b of the double container 1. As shown in FIG. Therefore, the bottom portion 14a of the inner bag 14 is easily separated from the bottom portion 7b of the double container 1 and floats up. The outside air introduction part 15 may be formed by perforating the outer shell 12 . The outside air introduction portion 15 may be provided in the housing portion 7 or may be provided in the mouth portion 9 .

<Leak inspection device 2>
2 to 4, the leak inspection device 2 used for implementing the leak inspection method for the double container 1 of the present embodiment will be described. The leak inspection device 2 includes a head 3 , an electromagnetic valve 4 , a pressure reducing system 5 , a pressurizing system 6 and a pipe 8 . The pipe 8 includes a pipe 8 a connecting the head 3 and the solenoid valve 4 , a pipe 8 b connecting the decompression system 5 and the solenoid valve 4 , and a pipe 8 c connecting the pressurization system 6 and the solenoid valve 4 . By controlling the electromagnetic valve 4, it is possible to switch which of the decompression system 5 and the pressurization system 6 is connected to the head 3. FIG. Air can be sucked through the head 3 by the decompression system 5 , and air can be blown through the head 3 by the pressurization system 6 .

The pressure reduction system 5 includes a flow meter 51, a pressure gauge 52, a regulator 53, and a vacuum pump 54 in order from the electromagnetic valve 4 side. The vacuum pump 54 reduces the pressure in the pipe 8b by discharging the air in the pipe 8b. The regulator 53 controls the flow rate of the air flowing through the pipe 8b or the pressure of the air inside the pipe 8b. A pressure gauge 52 measures the pressure of air in the pipe 8b. The flow meter 51 measures the flow rate of air flowing through the pipe 8b. The order of components included in the pressure reduction system 5 may be changed or omitted as appropriate.

The pressurization system 6 includes a speed controller 61, a regulator 62, and a compressor 63 in order from the solenoid valve 4 side. The compressor 63 supplies compressed air into the pipe 8c. The regulator 62 controls the pressure of the air inside the pipe 8c. The speed controller 61 controls the flow rate of air flowing through the pipe 8c. Note that the pressurization system 6 can be omitted when unnecessary, and in that case, the electromagnetic valve 4 can also be omitted.

The head 3 includes a head base 31 and packing 32 . The head base 31 and the packing 32 are provided with through holes 31a and 32a communicating with the inside of the pipe 8a, respectively. The packing 32 is arranged inside the housing recess 31 b of the head base 31 . The packing 32 is made of a material such as elastomer that can improve airtightness. According to such a configuration, as shown in FIG. 4, when the head base 31 is pressed toward the end face of the mouth portion 9, the head base 31 and the end face of the mouth portion 9 are brought into close contact with each other through the packing 32, and the inner bag is sealed. The interior of the inner bag 14 communicates with the outside only through the through holes 31a and 32a.

<Leak inspection method>
A leak inspection method for the double container 1 of the present embodiment will be described. This method comprises the step of determining whether there is a pinhole in the inner bag 14 based on data obtained when the pressure inside the inner bag 14 is reduced.

This step can be performed by connecting the head 3 to the decompression system 5 and operating the vacuum pump 54 with the head 3 pressed against the end surface of the mouth portion 9 . As a result, the air inside the inner bag 14 is sucked out, the pressure inside the inner bag 14 is reduced, and the inner bag 14 contracts as shown in FIG.

As shown in FIG. 6, after the pressure reduction starts, the air flow rate measured by the flow meter 51 rapidly increases, but the flow rate gradually decreases as the inner bag 14 contracts. If the inner bag 14 has no pinholes, the air flow rate becomes very small (almost 0) when the inner bag 14 completely deflates. On the other hand, if the inner bag 14 has pinholes, air flows into the inner bag 14 through the pinholes even if the inner bag 14 is completely deflated. More than if there were no pinholes in bag 14 . Therefore, based on the flow rate of the air sucked out from the inner bag 14 (more specifically, by confirming whether or not this flow rate exceeds the threshold value Th) after the predetermined time T elapses, the inner bag 14 It can be determined whether there is a pinhole in the

Further, when the inner bag 14 has a pinhole, the degree of airtightness inside the inner bag 14 becomes low, so that the degree of pressure reduction in the inner bag 14 becomes difficult to increase. Therefore, with the set pressure of the vacuum pump 54 set to the reference value, it is determined whether or not there is a pinhole in the inner bag 14 based on the pressure detected by the pressure gauge 52 after the elapse of a predetermined time. can be done. In addition to the flow rate and pressure, it is also possible to determine the presence or absence of pinholes based on data such as the shrinkage mode and shrinkage time of the inner bag 14 . However, from the viewpoint of accuracy, the determination based on the flow rate is preferable.

When the inner bag 14 is in contact with the outer shell 12, even if there is a pinhole in the inner bag 14, the pinhole may be overlooked because the pinhole is blocked by the outer shell 12. In the method of the present embodiment, pinhole inspection is performed while depressurizing the inside of the inner bag 14, so pinholes are less likely to be overlooked.

The leak inspection method of the present embodiment may be performed after a preliminary peeling step of peeling the inner bag 14 from the outer shell 12 is performed in advance. 12 may be peeled off. In that case, preliminary peeling and leak inspection can be performed at the same time, which is efficient.

In addition, in the case of a highly transparent double container, it is possible to visually confirm the presence or absence of pinholes in the inner bag 14, but in the case of a colored double container, it is difficult to visually confirm. . Therefore, the inspection method according to the present embodiment has a significant technical significance in leak inspection of a colored double container.

After the leak test is completed, the electromagnetic valve 4 is operated to connect the head 3 to the pressurization system 6, and in this state, the compressor 63 is operated to send air into the inner bag 14, thereby closing the inner bag 14. Inflate. This facilitates the process of filling the inner bag 14 with the contents.

2. Second Embodiment This embodiment is similar to the first embodiment, and the main difference is in the configuration of the head 3 . The following description will focus on the differences.

In this embodiment, the head 3 further includes an insertion member 33 and a packing 34, as shown in FIG. The insertion member 33 includes a rod-shaped portion 33a and a flange portion 33b radially protruding from the proximal end of the rod-shaped portion 33a. A through-hole 34a is provided in the packing 34, and the bar-shaped portion 33a is inserted through the through-hole 34a. The material of packing 34 is similar to that of packing 32 . The rod-shaped portion 33a is a rod-shaped portion.

As shown in FIG. 8, the insertion member 33 is provided with a through hole 33c, and the bar-shaped portion 33a is provided with a suction port 33d communicating with the through hole 33c. 33 d of suction ports are provided in the front-end|tip 33a1 of the rod-shaped part 33a. Since tip 33a1 is less likely to be covered by inner bag 14 when inner bag 14 contracts, suction port 33d is less likely to be blocked by inner bag 14 by providing suction port 33d at tip 33a1. Since the rod-shaped portion 33a is a portion to be inserted into the inner bag 14, it is preferable that the side and tip edges of the rod-shaped portion 33a are curved so that the rod-shaped portion 33a does not damage the inner bag 14.

According to the above configuration, as shown in FIG. The interior of the inner bag 14 communicates with the outside only through the through-holes 31a, 32a, and 33c, so that the inner bag 14 can be decompressed or pressurized by the decompression system 5 or the pressurization system 6. .

In the leak inspection method of the present embodiment, the inside of the inner bag 14 is decompressed while the bar-shaped portion 33a is inserted into the inner bag 14 from the mouth portion 9, and the inner bag 14 is contracted as shown in FIG. to check the presence or absence of pinholes in the inner bag 14. According to such a method, the following effects are exhibited.

・Suppression of biased peeling of the inner bag 14 As shown in FIG. As shown in FIG. 10, the inner bag 14 may be partially peeled and shrunk so that peeling progresses only at the portion 14b and does not progress at the portion 14c. If the inner bag 14 is shrunk in this manner, it is problematic because the leak test cannot be effectively performed at the portion 14c. In the present embodiment, as shown in FIG. 9, the interior of the inner bag 14 is decompressed while the rod-shaped portion 33a is inserted. At the point of contact, the peeling at the portion 14b stops, and thereafter the peeling at the portion 14c progresses. Therefore, according to the present embodiment, uneven peeling of the inner bag 14 is suppressed, and leak inspection can be performed effectively.

Suppression of lifting of the bottom portion 14a of the inner bag 14 In the first embodiment, when the inner bag 14 further shrinks while the inner surfaces of the portions 14b and 14c are in contact with each other, an upward force is applied to the bottom portion 14a of the inner bag 14. , as shown in FIG. 10, there is a possibility that the bottom portion 14a is separated from the bottom portion 7b of the double container 1 and floats up. On the other hand, in this embodiment, as shown in FIG. The application of an upward force is suppressed, and as a result, the phenomenon in which the bottom portion 14a separates from the bottom portion 7b of the double container 1 and floats is suppressed.

As shown in FIG. 8, where H is the total height of the double container 1 and L is the length of the portion of the rod-shaped portion 33a that is inserted into the inner bag 14, L/H is 0.40 or more. Preferably. This is because in this case, the above two effects are effectively exhibited. L/H is, for example, 0.40 to 0.99, specifically, for example, 0.40, 0.50, 0.60, 0.70, 0.80, 0.90, 0.95, 0.99 and may be in the range between any two of the numbers exemplified herein.

As shown in FIG. 8, when the diameter of the inscribed circle of the inner peripheral surface of the mouth portion 9 is D1 and the diameter of the circumscribed circle of the rod-like portion 33a is D2, D2/D1 is preferably 0.30 or more. This is because in this case, the above two effects are effectively exhibited. D2/D1 is, for example, 0.30 to 0.99, specifically, for example, 0.30, 0.40, 0.50, 0.60, 0.70, 0.80, 0.90, 0.95, 0.99, and may be in the range between any two of the values exemplified herein.

Also, L/D2 is preferably 3 or more, for example, 3 to 50, specifically for example, 3, 4, 5, 6, 7, 8, 9, 10, 20, 30, 40 , 50, and may be in the range between any two of the values exemplified herein.

In this embodiment, excellent effects can be obtained as a leak inspection method, and from the viewpoint of achieving the above two effects, the present embodiment can also provide excellent effects as a preliminary peeling method for the double container 1 . Therefore, leak inspection is not essential from this point of view.

This embodiment can also be implemented in the following aspects.
- The suction port 33d may be provided at a location other than the tip of the rod-shaped portion 33a. When the suction port 33d is provided on the peripheral surface of the rod-shaped portion 33a, it is preferably provided at a position where the inner bag 14 is unlikely to block the suction port 33d (for example, near the base of the rod-shaped portion 33a). The number of suction ports 33d may be two or more.
- You may provide the through-hole 33c in the flange part 33b. In this case, the packings 32 and 34 are provided with through-holes communicating with the through-holes 33c. With such a configuration, it is possible to reduce the pressure inside the inner bag 14 through the through hole 33c of the flange portion 33b. In this case, the rod-shaped portion 33a may also be provided with a through-hole 33c so that the interior of the inner bag 14 is decompressed through both the rod-shaped portion 33a and the flange portion 33b. The inner bag 14 may be decompressed only by the flange portion 33b without providing the 33c.

Reference Signs List 1: Double container 2: Leak inspection device 3: Head 4: Solenoid valve 5: Decompression system 6: Pressurization system 7: Storage part 7a: Body part 7b: Bottom part 7d: Cutout part 8: Piping 8a: Piping 8b: Piping 8c : Piping 9 : Mouth 12 : Outer shell 14 : Inner bag 14a : Bottom 14b : Part 14c : Part 15 : Outside air introduction part 31 : Head base 31a : Through hole 31b : Storage recess 32 : Packing 32a : Through hole 33 : Insertion member 33a: Rod-shaped portion 33a1: Tip 33b: Flange portion 33c: Through hole 33d: Suction port 34: Packing 34a: Through hole 51: Flow meter 52: Pressure gauge 53: Regulator 54: Vacuum pump 61: Speed controller 62: Regulator 63: Compressor

Claims (3)

A leak test method for a double container,
The double container has an outer shell and an inner bag, and is configured such that the inner bag shrinks as the contents decrease,
The method comprises a leak inspection step and a preliminary stripping step,
The leak inspection step determines whether or not a pinhole exists in the inner bag based on data obtained when the pressure inside the inner bag is reduced,
The preliminary peeling step peels the inner bag from the outer shell by reducing the pressure inside the inner bag,
The method, wherein the leak inspection step and the preliminary stripping step are performed simultaneously. 2. The method of claim 1, wherein
The method, wherein the determination is performed based on the flow rate of air sucked out from the inner bag during the pressure reduction. A method according to claim 1 or claim 2,
The method, wherein the decompression is performed with a rod-shaped portion inserted into the inner bag from the mouth portion of the double container.