Leak test method and leak test device

Abstract

To enable leak test that requires less time and prevents a container from shrinking during leak test.SOLUTION: A leak test method for testing for leakage of a flexible container 110 placed inside a housing 120 is provided, the method comprising applying a pressing force to the container 110 from the inside of the container 110, introducing a test fluid into a hollow space 130 between the housing 120 and the container 110, and testing for leakage of the test fluid to the inside of the container 110.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a leak inspection method and a leak inspection device. [Background technology]

[0002] Conventionally, a double container has been known which has an outer container and a flexible inner container placed inside it, in which the inner container separates from the outer container and shrinks as the contents, such as food, contained in the inner container decrease, thereby preventing air from entering the inner container. Patent Document 1 discloses a leak inspection method (pinhole check method) for inspecting whether there is a hole in the inner container of such a double container by leaking a test gas. In the leak inspection method of Patent Document 1, after the inner container (inner bag) is preliminarily peeled off from the outer container (outer shell), a test gas is injected into the hollow space between the outer container and the inner container, and leakage of the test gas through the inner container is detected (sensed). During the preliminarily peeling, for example, air is blown into the hollow space or negative pressure is created inside the inner container. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2015-152572 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, the leak inspection method of Patent Document 1 has a problem in that the inspection time is increased by the amount of preliminary peeling. In addition, in the leak inspection method of Patent Document 1, when the inspection gas (inspection fluid) is injected into the hollow space between the outer container and the inner container, the flexible inner container shrinks. This causes a problem that the hole in the inner container is blocked by the shrinking inner container itself. In this case, there is a possibility that the gas leak (leak) of the inner container cannot be inspected correctly.

[0005] The present invention has been made in consideration of the above-mentioned circumstances, and aims to provide a leak testing method and a leak testing device that can perform a leak test in a shorter time and prevent the inner container from shrinking during the leak test. [Means for solving the problem]

[0006] One aspect of the present invention is a leak testing method for a flexible container placed inside a container, comprising the steps of applying a pressing force to the container from inside the container, introducing a test fluid into a hollow space between the container and the container, and testing for leakage of the test fluid into the inside of the container.

[0007] One aspect of the present invention is a leak testing device for testing for leaks in a flexible container placed inside a container, the leak testing device comprising: a force application section that applies a pressing force to the container from inside the container; a fluid introduction section that introduces a test fluid into a hollow space between the container and the container; and a fluid sensor that is placed inside the container and measures the test fluid. Effect of the Invention

[0008] According to the present invention, a leak test can be performed in a shorter time and the container can be prevented from shrinking during the leak test. [Brief description of the drawings]

[0009] [Figure 1] FIG. 2 is a diagram showing a step of introducing a test fluid into a hollow space in a leak testing method for testing a container (inner container) of a double container using the leak test device according to the first embodiment. [Diagram 2] FIG. 2 is a diagram showing a step of inspecting for leakage from a hollow space to the inside of the container after the step of FIG. 1. [Diagram 3] 13 is a diagram showing a modified example of the pressing member in the leak test device according to the first embodiment, illustrating a state after the pressing member has been placed in a container. FIG. [Figure 4]4A to 4C are diagrams showing a process of inserting and removing the pressing member in FIG. 3 into and from a container. [Diagram 5] FIG. 11 is a diagram showing a leak inspection method for inspecting a container (inner container) of a double container for leaks using the leak inspection device according to the second embodiment. [Figure 6] FIG. 13 is a diagram showing a step of introducing a test fluid into a hollow space in a leak testing method for testing a container (inner container) of a double container using a leak test device according to a third embodiment. [Figure 7] FIG. 7 is a diagram showing a step of inspecting for leakage from the hollow space to the inside of the container after the step of FIG. 6. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] First Embodiment Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. 1 and 2, the leak test device 1 of the first embodiment is a device that tests for leaks in a flexible container 110 disposed inside a container 120. Specifically, the leak test device 1 is a device that tests for gas leaks in the container 110.

[0011] In this embodiment, the housing 120 and the container 110 constitute a double container 100. In the double container 100, the container 110 is flexible and functions as an inner container in which contents such as food are contained. The housing 120 is flexible and functions as an outer container in which the inner container is disposed. The container 110 disposed inside the housing 120 has an opening 111 facing the outside of the housing 120. The housing 120 has an opening 125 that allows the opening 111 of the container 110 to face the outside of the housing 120. However, the periphery of the opening 125 of the housing 120 is connected to the periphery of the opening 111 of the container 110 over the entire circumference. In other words, the opening 125 of the housing 120 is blocked by the container 110.

[0012] There is a hollow space 130 between the inside of the container 120 and the outside of the vessel 110. The volume of the hollow space 130 varies depending on the state of the container 120 and the vessel 110, which are flexible. The hollow space 130 is connected to the outside of the container 120 through openings 121, 122 (first opening 121, second opening 122) formed in the container 120.

[0013] Although not shown, in the double container 100 after manufacture, check valves are provided at the openings 121, 122 of the housing 120 (outer container). The check valves allow gas such as air to enter the hollow space 130 from the outside, but prevent gas from escaping from the hollow space 130 to the outside. Therefore, in the double container 100 after manufacture, gas enters the hollow space 130 as the contents, such as food, are discharged to the outside of the container 110 (inner container). As a result, the container 110 separates from the housing 120 and shrinks, preventing air from entering the container 110.

[0014] The leak test device 1 includes a force application unit 2, a gas introduction unit 3 (fluid introduction unit), and a gas sensor 4 (fluid sensor). The leak test device 1 of this embodiment further includes a lid unit 5, a gas discharge unit 6 (fluid discharge unit), and a block plug 7.

[0015] The force application unit 2 applies a pressing force to the container 110 from inside the container 110. The force application unit 2 in this embodiment is a pressing member 21 that extends from the opening 111 of the container 110 to the inside of the container 110 and is pressed against the inner surface of the container 110. The pressing member 21 illustrated in FIGS. 1 and 2 is a simple rod-shaped member. It is preferable that the tip of the pressing member 21 that is pressed against the inner surface of the container 110 is rounded. This can suppress or prevent the inner surface of the container 110 from being damaged by the pressing member 21.

[0016] The gas introduction unit 3 introduces a test gas (fluid for testing) into the hollow space 130 between the container 120 and the vessel 110. In this embodiment, the gas introduction unit 3 introduces the test gas into the hollow space 130 from the first opening 121 of the container 120. The gas introduction unit 3 may be a supply source of the test gas such as a gas cylinder, or may be a compressor that pressure-feeds the test gas toward the hollow space 130. The test gas may be any gas that can be detected by at least the gas sensor 4. In consideration of availability (ease of availability) and cost, the test gas is preferably hydrogen gas. However, the test gas may be helium gas or the like.

[0017] The gas sensor 4 is disposed inside the container 110 and measures the test gas. The gas sensor 4 of this embodiment outputs an electrical signal corresponding to the concentration of the measured test gas. The gas sensor 4 is connected to a sensor head 8 disposed outside the container 110 by electrical wiring (not shown). The sensor head 8 is equipped with devices for driving the gas sensor 4, etc.

[0018] 1 and 2, the gas sensor 4 is attached to the pressing member 21. The gas sensor 4 is attached to the middle part of the rod-shaped pressing member 21 in the longitudinal direction. This allows the gas sensor 4 to be disposed in the center part of the space within the container 110. By disposing the gas sensor 4 in the center part of the space within the container 110, it is possible to suppress the occurrence of deviation in the distance from the gas sensor 4 to the inner surface of the container 110, compared to a case in which the gas sensor 4 is disposed at an offset position in the space within the container 110. This makes it easier for the gas sensor 4 to detect the test gas leaked inside the container 110.

[0019] The sensor head 8 may be connected to, for example, a determination device (not shown). The determination device determines whether or not the test gas is leaking from the outside (hollow space 130) of the container 110 to the inside based on the concentration of the test gas measured by the gas sensor 4. For example, the determination device may determine that the test gas is leaking inside the container 110 when the measured concentration of the test gas is greater than a predetermined threshold, and may determine that the test gas is not leaking inside the container 110 when the measured concentration of the test gas is equal to or less than the predetermined threshold. The above "threshold" may be 0% or a predetermined numerical value equal to or greater than 0%. A "threshold" of 0% means that the presence or absence of the test gas inside the container 110 is inspected.

[0020] The lid part 5 closes the opening 111 of the container 110. The lid part 5 only needs to close the opening 111 of the container 110 at least when the test gas is measured by the gas sensor 4 arranged inside the container 110. In Figs. 1 and 2, the pressing member 21 and the sensor head 8 are fixed integrally to the lid part 5, but the present invention is not limited to this.

[0021] When the gas introduction unit 3 introduces the test gas into the hollow space 130, the gas exhaust unit 6 exhausts the air (gas mainly composed of nitrogen and oxygen) present in the hollow space 130 to the outside of the container 120. In this embodiment, the gas exhaust unit 6 exhausts the air in the hollow space 130 to the outside of the container 120 from the second opening 122 of the container 120. The gas exhaust unit 6 may be, for example, a vacuum pump. The gas exhaust section 6 and the above-mentioned gas inlet section 3 replace the air present in the hollow space 130 with the test gas.

[0022] The block plug 7 blocks the openings 121, 122 (first opening 121 and second opening 122) of the container 120. The block plug 7 blocks the openings 121, 122 of the container 120 after the test gas is introduced into the hollow space 130 and after the air in the hollow space 130 is discharged to the outside of the container 120. The block plug 7 only needs to block the openings 121, 122 of the container 120 when the test gas is measured by the gas sensor 4 arranged inside the vessel 110. The block plug 7 is removed from the container 120 after the test gas is measured by the gas sensor 4.

[0023] Next, an example of the leak inspection method according to the first embodiment will be described. 1, a pressing force is applied to the container 110 from inside the container 110. In this embodiment, the tip of a pressing member 21 extending inward from an opening 111 of the container 110 is pressed against the inner surface of the container 110, thereby applying a pressing force from inside the container 110. In addition, a gas sensor 4 is disposed inside the container 110. More specifically, in this embodiment, the pressing member 21 is fixed integrally to the lid portion 5, and the gas sensor 4 is attached to the pressing member 21. Therefore, by closing the opening 111 of the container 110 with the lid portion 5, the tip of the pressing member 21 is pressed against the inner surface of the container 110, and the gas sensor 4 is disposed inside the container 110. That is, when the opening 111 of the container 110 is closed by the lid portion 5, a pressing force is applied from the inside of the container 110, and the gas sensor 4 is disposed inside the container 110.

[0024] Next, the test gas is introduced into the hollow space 130 between the container 120 and the vessel 110. By introducing the test gas into the hollow space 130, the air pressure (pressure) in the hollow space 130 is made higher than the air pressure (pressure) in the vessel 110. When the test gas is introduced, a pressing force is applied from inside the vessel 110 as described above. Therefore, even if the air pressure in the hollow space 130 becomes higher than the air pressure in the vessel 110 due to the introduction of the test gas, it is possible to prevent the vessel 110 from collapsing. The air pressure in the hollow space 130 after the test gas is introduced into the hollow space 130 may be, for example, 5 kPa (G) to 80 kPa (G).

[0025] In this embodiment, when introducing the test gas into the hollow space 130, the gas inlet 3 introduces the test gas into the hollow space 130 from the first opening 121 of the container 120, and the gas outlet 6 exhausts the air present in the hollow space 130 from the second opening 122 of the container 120 to the outside of the container 120. This replaces the air in the hollow space 130 with the test gas.

[0026] After the test gas is introduced into the hollow space 130, a test is performed to check for leakage of the test gas into the inside of the container 110, as shown in Fig. 2. During this leak test, the test gas is measured by a gas sensor 4 arranged inside the container 110. During the leak test, the openings 121 and 122 of the container 120 are blocked by a blocking plug 7 to prevent the test gas from leaking outside the container 120 and to prevent a decrease in air pressure in the hollow space 130.

[0027] In the leak test, if the container 110 has a hole, the test gas leaks from the hollow space 130 to the inside of the container 110 through the hole in the container 110, and the concentration of the test gas measured by the gas sensor 4 becomes higher than the predetermined concentration (threshold value). If the container 110 has no hole, the test gas does not leak to the inside of the container 110, and the concentration of the test gas measured by the gas sensor 4 becomes lower than the predetermined concentration (threshold value).

[0028] As described above, with the leak test device 1 and the leak test method of the first embodiment, it is possible to test for leakage of the test gas from the outside to the inside of the container 110. Then, by introducing a test gas into the hollow space 130 between the inside of the container 120 and the outside of the container 110, the container 120 and the container 110 can be peeled off. That is, the container 120 and the container 110 can be peeled off without performing a preliminary peeling as in Patent Document 1. This allows the leak test of the container 110 to be performed in a shorter time. Furthermore, by applying a pressing force to the container 110 from inside the container 110 when introducing the test gas into the hollow space 130, it is possible to suppress the container 110 from collapsing even when the test gas is introduced into the hollow space 130. Therefore, it is possible to suppress or prevent the hole in the container 110 from being blocked by the deflated container 110 itself, and to more accurately perform the leak test.

[0029] Furthermore, in the leak test device 1 and leak test method of the first embodiment, a pressing force is applied to the container 110 from the inside of the container 110 by pressing the pressing member 21 extending from the opening 111 of the container 110 to the inside of the container 110 against the inner surface of the container 110. This makes it possible to apply a pressing force to the container 110 from the inside of the container 110 at a lower cost and in a shorter time than in the case where the air pressure inside the container 110 is increased.

[0030] Furthermore, in the leak test device 1 and leak test method of the first embodiment, the test gas is introduced into the hollow space 130 from the first opening 121 of the container 120, and the air present in the hollow space 130 is discharged to the outside of the container 120 from the second opening 122 of the container 120, thereby replacing the air in the hollow space 130 with the test gas. Therefore, it is possible to introduce a high concentration of the test gas into the hollow space 130 without excessively increasing the air pressure in the hollow space 130. This makes it possible to effectively prevent the container 110 from collapsing due to the air pressure in the hollow space 130.

[0031] In the first embodiment, as shown in Figs. 3 and 4, the pressing member 21A may have a portion that branches into a plurality of portions and is pressed against the inner surface of the container 110. The pressing member 21A illustrated in Figs. 3 and 4 has a rod-shaped trunk portion 211 and a plurality of branch portions 212 extending from the trunk portion 211. The trunk portion 211 corresponds to the rod-shaped pressing member 21 shown in Figs. 1 and 2. The tips of the trunk portion 211 and each branch portion 212 pressed against the inner surface of the container 110 are preferably rounded. Each of the plurality of branch portions 212 is movable between a folded position P1 shown in Fig. 4 and an unfolded position P2 shown in Fig. 3 relative to the trunk portion 211. In Fig. 4, the folded position P1 of the branch portion 212 is a position where the inclination angle of the branch portion 212 with respect to the trunk portion 211 is small. In FIG. 3, the deployed position P2 of the branch-like portion 212 is a position where the inclination angle of the branch-like portion 212 with respect to the trunk portion 211 is large.

[0032] As described above, when the tips of the multiple portions (mainly the multiple branch-like portions 212) of the pressing member 21A are pressed against the inner surface of the container 110, wrinkles are less likely to occur in the container 110 compared to when the pressing member 21A is pressed against only one point on the inner surface of the container 110. Therefore, when there is a hole in the container 110, it is possible to more effectively suppress or prevent the hole in the container 110 from being blocked by the container 110 itself.

[0033] In addition, in the above-described pressing member 21A, the multiple branch-like portions 212 can be folded relative to the trunk portion 211. Therefore, as shown in Fig. 4, when the multiple branch-like portions 212 are folded, the pressing member 21A can be easily inserted into and removed from the container 110 even if the opening 111 of the container 110 is small. In addition, as shown in Fig. 3, when the pressing member 21A is disposed inside the container 110, by moving the multiple branch-like portions 212 from the folded position P1 to the deployed position P2, the tips of the multiple branch-like portions 212 can be pressed against the inner surface of the container 110 even if the space inside the container 110 is large.

[0034] Second Embodiment Next, a second embodiment of the present invention will be described with reference to Fig. 5. In the following description, configurations common to those already described will be given the same reference numerals and duplicated description will be omitted.

[0035] As shown in Fig. 5, the leak test apparatus 1E of the second embodiment further includes an airflow generating unit 9 (flow generating unit) compared to the leak test apparatus 1 of the first embodiment (see Figs. 1 and 2). The airflow generating unit 9 is disposed inside the container 110, and generates an airflow (flow) toward the gas sensor 4 inside the container 110. The airflow generating unit 9 illustrated in Fig. 5 is a propeller fan, but is not limited thereto. In the second embodiment, the airflow generating unit 9 is attached to a rod-shaped pressing member 21 together with the gas sensor 4. The airflow generating unit 9 is disposed on both sides of the gas sensor 4 in the longitudinal direction of the pressing member 21. The airflow generating unit 9 may be disposed on only one side of the gas sensor 4, for example.

[0036] The leak testing method of the second embodiment is similar to the leak testing method of the first embodiment, except that an airflow generating unit 9 or the like is used to generate an airflow toward the gas sensor 4 inside the container 110. In the leak testing method of the second embodiment, an airflow toward the gas sensor 4 is generated inside the container 110 when the test gas inside the container 110 is measured by the gas sensor 4.

[0037] The leak test device 1E and the leak test method of the second embodiment have the same effects as those of the first embodiment. Furthermore, in the leak test device 1E and the leak test method of the second embodiment, when the test gas inside the container 110 is measured by the gas sensor 4, an airflow toward the gas sensor 4 is generated inside the container 110. Therefore, even if the amount of test gas leaking inside the container 110 is small because the hole formed in the container 110 is small, or even if the hole formed in the container 110 is located away from the gas sensor 4, the test gas leaked inside the container 110 can be efficiently directed toward the gas sensor 4. Therefore, the leak test of the container 110 can be performed in a shorter time.

[0038] The leak test device 1E of the second embodiment may employ a pressing member 21A including a trunk portion 211 and a plurality of branch portions 212 as exemplified in Figures 3 and 4. In this case, the airflow generating unit 9 may be attached to the trunk portion 211, for example.

[0039] Third Embodiment Next, a third embodiment of the present invention will be described with reference to Figures 6 and 7. In the following description, components common to those already described will be given the same reference numerals and duplicated description will be omitted.

[0040] As shown in Figures 6 and 7, the leak test apparatus 1F of the third embodiment is different from the leak test apparatus 1 of the first embodiment (see Figures 1 and 2) in the configuration of the force application section 2 that applies a pressing force to the container 110 from inside the container 110.

[0041] The force application unit 2 in the third embodiment is a pressurizing unit 23 that increases the air pressure inside the container 110. The pressurizing unit 23 may be, for example, a compressor. The pressurizing unit 23 is connected to the inside of the container 110 via an inlet pipe 24. The inlet pipe 24 penetrates the lid unit 5 that closes the opening 111 of the container 110. This allows the air pressure inside the container 110 to be increased by introducing a pressurizing gas from the pressurizing unit 23 into the inside of the container 110. The pressurizing gas may be any gas other than at least the test gas, and may be, for example, air.

[0042] The leak test apparatus 1F of the third embodiment also includes a configuration for lowering the air pressure inside the container 110. Specifically, a discharge pipe 25 for discharging gas (such as pressurizing gas) inside the container 110 to the outside is connected to a midpoint of the inlet pipe 24. The discharge pipe 25 has an open end that is open to the atmosphere. A first valve V1 for opening and closing the inlet pipe 24 is provided on the upstream side (pressurizing unit 23 side) of the branch point with the discharge pipe 25 of the inlet pipe 24. In addition, a second valve V2 for opening and closing the discharge pipe 25 is provided on the discharge pipe 25.

[0043] In order to increase the air pressure inside the container 110, the first valve V1 is opened and the second valve V2 is closed, and a pressurizing gas is introduced into the container 110 by the pressurizing unit 23. On the other hand, in order to decrease the air pressure inside the container 110, the first valve V1 is closed and the second valve V2 is opened. In this state, the gas inside the container 110 is discharged to the outside according to the air pressure difference between the inside of the container 110 and the open end of the discharge pipe 25, and the air pressure inside the container 110 can be decreased.

[0044] In the leak test device 1F of the third embodiment, the gas sensor 4 is attached to the tip of an extension member 41 extending inward from the lid portion 5 that closes the opening 111 of the container 110. This allows the opening 111 of the container 110 to be closed by the lid portion 5, and at the same time, the gas sensor 4 can be disposed at a predetermined position inside the container 110 (for example, the center part of the space inside the container 110). The extension member 41 may be, for example, a rod that has no flexibility, or may be a flexible string. In Figs. 6 and 7, the extension member 41 also serves as an electrical wiring for connecting the gas sensor 4 to the sensor head 8, and penetrates the lid portion 5.

[0045] Next, an example of a leak inspection method according to the third embodiment will be described. 6, in the leak testing method of the third embodiment, a pressing force is applied to the container 110 from inside the container 110 by increasing the air pressure inside the container 110. Specifically, the opening 111 of the container 110 is closed by the lid 5, the first valve V1 is opened, and the second valve V2 is closed. In this state, a pressurizing gas is introduced into the container 110 by the pressurizing unit 23, thereby increasing the air pressure inside the container 110.

[0046] Next, the test gas is introduced into the hollow space 130 between the container 120 and the vessel 110. When the test gas is introduced into the hollow space 130, the air pressure in the hollow space 130 is set to be equal to or lower than the air pressure in the vessel 110 so that the vessel 110 does not shrink when the test gas is introduced into the hollow space 130. For example, when the air pressure in the hollow space 130 is 5 kPa(G) to 80 kPa(G), the air pressure in the vessel 110 may be set to 10 kPa(G) to 85 kPa(G), which is about 5 kPa higher than the air pressure in the hollow space 130. In the third embodiment, similarly to the first embodiment, the gas inlet 3 introduces the test gas into the hollow space 130 from the first opening 121 of the container 120, and the gas outlet 6 exhausts the air present in the hollow space 130 from the second opening 122 of the container 120 to the outside of the container 120. This replaces the air in the hollow space 130 with the test gas.

[0047] After the test gas is introduced into the hollow space 130, as shown in FIG. 7, leakage of the test gas into the inside of the container 110 is checked in the same manner as in the first embodiment. However, in the third embodiment, the air pressure inside the container 110 is made lower than the air pressure in the hollow space 130 during the leak check. Specifically, the first valve V1 is closed and the second valve V2 is opened to discharge the gas inside the container 110 to the outside, thereby making the air pressure inside the container 110 lower than the air pressure in the hollow space 130. As a result, if there is a hole in the container 110, the test gas leaks from the hollow space 130 through the hole in the container 110 to the inside of the container 110, and the test gas leaked into the inside of the container 110 can be measured by the gas sensor 4.

[0048] The leak test apparatus 1F and the leak test method of the third embodiment have the same effects as those of the first embodiment. Moreover, in the leak test device 1F and the leak test method of the third embodiment, the air pressure inside the container 110 is increased, thereby applying a pressing force to the container 110 from inside the container 110. This makes it possible to protect the container 110, compared to the case where the pressing member 21 is pressed against the inner surface of the container 110.

[0049] In the leak testing apparatus 1F and leak testing method of the third embodiment, as in the second embodiment, when measuring the test gas inside the container 110 using the gas sensor 4, an airflow may be generated inside the container 110 toward the gas sensor 4.

[0050] Although the present invention has been described in detail above, the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.

[0051] In the present invention, the number of openings in the container 120 is not limited to a plurality of openings, and may be, for example, a single opening. However, in order to replace the air present in the hollow space 130 with the test gas in a short period of time, it is preferable that the container 120 has a plurality of openings.

[0052] The present invention is not limited to a method for testing for leaks in the container 110 (inner container) in the double container 100, but can also be applied to a method for testing for leaks in a flexible container by, for example, the hood method. The leak testing method by the hood method is a method in which, for example, a flexible container is placed inside a container such as a hood, a test gas is introduced into a space (hollow space) inside the container and outside the container, and leakage of the test gas into the inside of the container is tested by a gas sensor.

[0053] In the present invention, the flow of gas inside the container or container is not limited to the flow of gas, but may be, for example, a liquid. In other words, it is sufficient that a fluid flows inside the container or container. Therefore, the present invention may be applied to, for example, a leak test for a liquid inside a container. In this case, for example, a test liquid may be introduced as a test fluid into the hollow space between the container and the container. Furthermore, the fluid originally present in the hollow space is not limited to a gas such as air, and may be any liquid. In this case, when performing a leak test, the liquid or gas present in the hollow space may be replaced with the test liquid. [Explanation of symbols]

[0054] Reference Signs List 1, 1E, 1F...Leak inspection device, 2...Force application section, 3...Gas inlet section (fluid inlet section), 4...Gas sensor (fluid sensor), 6...Gas exhaust section (fluid exhaust section), 8...Sensor head, 9...Airflow generation section (flow generation section), 21, 21A...Pressing member, 23...Pressing section, 100...Double container, 110...Container, 111...Opening, 120...Container, 121...First opening, 122...Second opening, 130...Hollow space

Claims

1. 1. A method for leak testing a flexible container disposed inside a housing, comprising: Applying a pressing force to the container from inside the container; Introducing a test fluid into the hollow space between the container and the vessel; A leak detection method for detecting leakage of the test fluid into the inside of the container.

2. 2. The leak test method according to claim 1, wherein a pressing force is applied to the container from inside the container by pressing a pressing member extending from the opening of the container to the inside of the container against an inner surface of the container.

3. The leak inspection method according to claim 1 , further comprising the step of increasing a pressure inside the container to apply a pressing force to the container from inside the container.

4. a fluid sensor for measuring the test fluid is disposed inside the container; 4. The leak testing method according to claim 1, further comprising the step of: generating a flow inside the container toward the fluid sensor when the test fluid inside the container is measured by the fluid sensor.

5. 4. The leak testing method according to claim 1, wherein when introducing the test fluid into the hollow space, the test fluid is introduced into the hollow space from a first opening of the container, and the fluid present in the hollow space is discharged to the outside of the container from a second opening of the container, thereby replacing the fluid present in the hollow space with the test fluid.

6. A leak testing method as described in any one of claims 1 to 3, wherein a double container is formed by the container functioning as an inner container in which the contents are contained, and the container which is flexible and functions as an outer container with the inner container disposed inside.

7. 1. A leak testing device for testing a flexible container disposed inside a housing, comprising: a force applying unit that applies a pressing force to the container from inside the container; a fluid introduction portion that introduces a test fluid into a hollow space between the container and the container; a fluid sensor disposed inside the container for measuring the test fluid.

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