System and method for performing a leak test on a sealed package

Abstract

A system is provided for performing a leak test on a package having a body with an opening, a gas permeable material covering the entire upper area of the opening, and an adhesive joint attaching the gas permeable material to the body adjacent the opening. The system includes a coupling element configured to connect to the package to enable a potential leak air flow path into the coupling element, the potential leak air flow path including a) a flow path from inside the package through the opening and further through the gas permeable material, and b) a flow path from the ambient atmosphere into the package and further through the gas permeable material.

Description

Technical Field

[0001] This technology includes a system and method for performing a leak test on a sealed package.

Background Art

[0002] Packages may be sealed to protect their contents from contamination. For example, sterile packages may be sealed to prevent the entry of bacteria and other microorganisms.

Summary of the Invention

Problems to be Solved by the Invention

[0003] Conventionally, such packages have been tested by vacuum collapse leak detection with the package placed inside a vacuum chamber.

Means for Solving the Problems

[0004] A system for performing a leak test on a package having a body with an opening, a gas permeable material covering the entire area of the opening, and an adhesive joint attaching the gas permeable material to the body adjacent to the opening is provided.

[0005] This system includes a coupling element. The coupling element is configured to connect to the package to enable a potential leak air flow path into the coupling element, and the potential leak air flow path includes: a) a path from inside the package through the opening and further through the gas permeable material; and b) a path from the surrounding atmosphere into the package and further through the gas permeable material.

[0006] Other elements of the system include a vacuum pump and a pressure sensor. The vacuum pump is operably connected to the coupling element to apply a test exhaust pressure to the leak air flow path. The pressure sensor operates to sense the test exhaust pressure within the coupling element. The controller is configured to monitor the profile of the test exhaust pressure within the coupling element, compare the profile of the test exhaust pressure with the profile of the reference exhaust pressure of a leak-free reference package, and determine whether there is a leak in the package based on the comparison.

[0007] A method for performing a leak test on a package having a body with an opening, a gas permeable material covering the entire area of the opening, and an adhesive joint attaching the gas permeable material to the body adjacent to the opening is provided.

[0008] The method includes coupling a vacuum system to the package to enable a potential leak air flow path into the vacuum system, the potential leak air flow path including a) a flow path from inside the package through the opening and further through the gas permeable material, and b) a flow path from the ambient atmosphere into the package and further through the gas permeable material.

[0009] The method also includes operating the vacuum system to apply a test exhaust pressure to the leak air flow path, monitoring the profile of the test exhaust pressure, and determining whether there is a leak in the package based on a comparison of the profile of the test exhaust pressure with the profile of the reference exhaust pressure of a leak-free reference package.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7A

Figure 7B

Figure 8A

Figure 8B

[0011] As shown in FIG. 1, package 100 includes a body 102 having an opening 103. The body 102 defines a storage volume 105, and in the illustrated example, the storage volume 105 is partially filled with contents 108 below a headspace 109. The contents 108 can be a solid, a liquid, or a mixture of both. The body 102 is formed of a gas-impermeable material that can be either highly rigid or flexible as needed for the package 100 to function as a cartridge, syringe, pouch, vial, etc. A closure element 112 closes the opening 103. Unlike the body 102, the closure element 112 is formed of a gas-permeable material. Alternatively, the package 100 can include a non-gas-permeable stopper 104 (e.g., a rubber stopper) below the opening 103, and in this embodiment, the headspace 109 is between the non-gas-permeable stopper 104 and the closure element 112.

[0012] The closing element 112 crosses over the opening 103 and reaches completely across the whole area, covering the opening 103. The closing element 112 further reaches to the outer surface portion 114 of the main body 102 surrounding the opening 103. The adhesive joint 116 attaches the closing element 112 to the outer surface portion 114 of the main body 102 all around the periphery of the opening 103. Thus, the opening 103 is closed by the gas-permeable material of the closing element 112 and sealed by the surrounding adhesive joint 116 between the gas-permeable material of the closing element 112 and the non-gas-permeable material of the main body 102.

[0013] The gas-permeable material of the closing element 112 can be high-density polyethylene (HDPE) such as Tyvek®. The gas-permeable material of the closing element 112 can be paper. The gas-permeable material of the closing element 112 can be a one-way valve that allows the flow of air out of the package 100 but does not allow the flow of air into the package 100. The main body 102 of the package 100 in a given example is formed from a single part of non-gas-permeable material, but instead, for example, it may have a plurality of parts such as an aluminum / plastic film or packaging material, or a crimping element that defines the outer surface portion 114 where the adhesive joint 116 seals the opening 103.

[0014] As shown in FIG. 2, the package 100 is coupled to a leak test system 200. The system 200 includes a coupling element 202 that is oriented to receive and support the package 100 in an upside-down test position as shown in the figure. Thus, the package 100 is arranged to discharge air downward from the package 100 through the closing element 112 of the opening 103 by the vacuum pressure within the system 200. The upside-down arrangement makes it more convenient to manually handle the package 100 compared to an upright arrangement where the package 100 is engaged from below by the coupling element 202. However, an upright arrangement may be preferred if the contents obstruct the air from passing downward through the storage space 105 to the opening 103.

[0015] As further shown in FIG. 2, the coupling element 202 defines an air flow path 205 having an inlet 207 and an outlet 209. The coupling element 202 includes a gasket 210 that supports the package 100 in the test position with the opening 103 aligned with the inlet 207. A conduit 212 communicates the vacuum pump 214 with the outlet 209. A pressure sensor 216 is operably connected to the conduit 212. The test system 200 also includes a controller 218 for operating the vacuum pump 214 and the pressure sensor 216.

[0016] The controller 218 may be a computer or may include any suitable processor(s), microprocessor(s), transceiver(s), memory, timer, analog / digital converter(s) (ADC), programmable logic controller(s) (PLC), human machine interface(s) (HMI), etc. to enable the functions as disclosed and claimed. The controller 218 may further include a suitable user interface and / or display to enable the output of test results and to enable a user to program or control the operation of the test system 200.

[0017] As shown in detail in an enlarged view in FIG. 3, combining the coupling element 202 and the package 100 enables potentially multiple air flow paths to the passage 205. These include air flow paths 300 that start from inside the package 100 (e.g., the headspace 109 and / or the storage space 105), pass through the opening 103 and the closing element 112 of the opening 103, and reach the outside. One or more additional air flow paths 310 that reach the outside through the opening 103 and the closing element 112 may start from the ambient atmosphere A and enter the storage space 105 (or the headspace 109) through a leak in the package 100. The leak may be within the main body 102 of the package 100, within the adhesive joint 116, or may be located between the main body 102 and a film, packaging material, crimping element, or other distinct part of the package 100 as described above. Another gas flow path 320 may start from the ambient atmosphere A and enter the passage 205 through a leak between the closing element 112 and the coupling element 202 (e.g., the gasket 210). Yet another air flow path 330 may reach from the ambient atmosphere A to the passage 205 only through the gas-permeable material of the closing element 112. In any case, the flow rate of air passing through the closing element 112 is determined by the pore size of the gas-permeable material forming the closing element 112. If there are pinholes in the gas-permeable material of the closing element 112, the flow rate along any of the air flow paths 300, 310, 320, and 330 may increase significantly.

[0018] During the execution of the leak test, the controller 218 operates the pump 214 to provide a vacuum pressure within the conduit 212 and the passage 205. The vacuum pressure draws air in and causes it to flow along one or more of the air flow paths 300, 310, 320, and 330. The controller 218 also monitors the vacuum pressure profile as detected by the sensor 216, thereby determining whether there is a leak.

[0019] Figure 4 shows an example of a profile of the test exhaust pressure (e.g., pressure vs. time) under various leakage conditions. The profile 400 of the reference exhaust pressure is obtained from a reference package without leakage. When there is no leakage in the package 100 under test while the pump 214 is operating, the air flow path 300 is the dominant air flow path. As air is drawn from the storage space 105 into the conduit 212, the pressure measured by the sensor 216 rapidly drops from the initial pressure 402 to a predetermined vacuum pressure 404 within the first predetermined period 406. The air flow path 330 may affect the pressure drop, but this effect is expected to be minimal and negligible. The initial pressure 402 is the pressure measured by the sensor 216 before the vacuum pump 214 operates. For example, the initial pressure 402 is the ambient atmospheric pressure. The predetermined vacuum pressure 404 varies depending on the capabilities of the test system 200. For example, the predetermined vacuum pressure 404 is the pressure in the high vacuum region, or the pressure when the pressure approaches the final vacuum of the test system 200. For example, the predetermined vacuum pressure 404 is about 500 millibars (mbar). The first predetermined period 406 can be any suitable period sufficient to obtain the final vacuum of the test system 200. For example, the second predetermined period 406 can be 10 seconds, 20 seconds, 30 seconds, 1 minute, etc.

[0020] The exhaust pressure profile of the reference package may vary slightly depending on the package and / or the different times at which the reference package is tested. Therefore, a test package having an exhaust pressure profile that substantially matches the profile 400 of the reference exhaust pressure is considered a "good" package, i.e., a package without leaks. If the deviation between the profile of the test exhaust pressure and the profile of the reference exhaust pressure is within the first predetermined threshold 408 within the first predetermined period 406, a "leak - free" status can be determined for the test package. The first predetermined threshold 408 can be any suitable predetermined statistical value such as, for example, 1 standard deviation (1 sigma), 2 standard deviations (2 sigma), 3 standard deviations (3 sigma), 4 standard deviations (4 sigma). For example, the profile 410 of the test exhaust pressure may deviate slightly from the profile 400 of the reference exhaust pressure, but since the deviation is within the first predetermined threshold 408, the test package is considered "good".

[0021] The profile 412 of the test exhaust pressure shows an example of the profile of a test package with a leak between the closure element 112 and the coupling element 202 (e.g., gasket 210). When the vacuum pump 214 operates, in addition to the air flow paths 300 and 330, air flows into the conduit 212 through the air flow path 320. Thus, as air is removed from the storage space 105, the pressure measured by the sensor 216 drops from the initial pressure 402, but the pressure drop is not as steep as the pressure drop in the profile 400 of the reference exhaust pressure, and the exhaust pressure does not reach the predetermined vacuum pressure 404 of the test system 200. If there is a leak between the closure material 112 and the coupling element 202 (e.g., gasket 210), the profile 412 of the test exhaust pressure exceeds the profile 400 of the reference exhaust pressure and exceeds the second predetermined threshold 414 within the second predetermined period 416.

[0022] The second predetermined threshold 414 can be any suitable value sufficient to distinguish it from the reference exhaust pressure profile 400 and the first predetermined threshold 408. For example, the second predetermined threshold 414 can be about 100 millibars (mbar). The second predetermined period 416 can be any suitable period sufficient to obtain a vacuum pressure close to the steady state. For example, the second predetermined period 416 can be 10 seconds, 20 seconds, 30 seconds, 1 minute, etc. The second predetermined period 416 can be the same as, shorter than, or longer than the first predetermined period 406.

[0023] The test exhaust pressure profile 418 is an example of the profile of a test package with a leak in the body 102 or other locations within the package 100. When the vacuum pump 214 operates, in addition to the air flow paths 300 and 330, air flows into the conduit 212 through the air flow path 310. Due to the presence of the air flow path 310, the pressure drop is gentler than the pressure drop of the test exhaust pressure profile 412, and the pressure does not approach the predetermined vacuum pressure 404. The test exhaust pressure profile 418 initially decreases due to the suction of the vacuum pump 214 and then may increase as air continues to leak from the surrounding atmosphere into the conduit 212. If there is a leak in the package 100 (including the body 102, film, packaging material, crimping element, or other separate parts of the package 100 described above, and / or the leak part of the adhesive joint 116), the test exhaust pressure profile 418 exceeds the reference exhaust pressure profile 400 and exceeds the third predetermined threshold 420 within the third predetermined period 422.

[0024] The third predetermined threshold 420 can be any suitable value sufficient to distinguish the reference exhaust pressure profile 400 and the test exhaust pressure profile 412. For example, the third predetermined threshold 420 can be about 100 millibars (mbar), 200 mbar, 300 mbar, etc. The third predetermined period 422 can be any suitable period sufficient to obtain a vacuum pressure close to the steady state. For example, the third predetermined period 422 can be 10 seconds, 20 seconds, 30 seconds, 1 minute, etc. The third predetermined period 422 can be the same as, shorter than, or longer than the first predetermined period 406 or the second predetermined period 416.

[0025] The test exhaust pressure profile 424 is an example of the profile of a test package with a pinhole in the closure element 112. When the vacuum pump 214 is operating, due to the presence of the pinhole, the flow rate of air flowing into the conduit 212 through the air flow path 300 may be greater than when there is no pinhole. As a result, the pressure drop may become steeper than the pressure drop of the reference exhaust pressure profile 400. If there is a pinhole in the closure element 112, the test exhaust pressure profile 424 falls below the reference exhaust pressure profile 400 and exceeds the fourth predetermined threshold 426 within the fourth predetermined period 428.

[0026] The fourth predetermined threshold 426 can be any suitable value sufficient to distinguish the reference exhaust pressure profile 400 and the test exhaust pressure profiles 410, 412, and 418. For example, the fourth predetermined threshold 426 can be below the reference exhaust pressure profile 400, 1 standard deviation (1 sigma), 2 standard deviations (2 sigma), 3 standard deviations (3 sigma), or 4 standard deviations (4 sigma). The fourth predetermined period 428 can be any suitable period, for example, 1 second, 2 seconds, 3 seconds, etc. The fourth predetermined period 428 can be the same as or shorter than the first predetermined period 406.

[0027] FIG. 5 shows a method 500 for performing a leak test on package 100 using test system 200. Method 500 includes a step 502 of coupling a conduit of the vacuum system to package 100 as described above with reference to FIG. 2. Step 502 can include applying and maintaining a compressive force that presses the coupling element 202 or gasket 210 against the closure element 212 on package 100.

[0028] Method 500 includes discharging air from the interior of package 100 through the gas permeable material of closure element 112 while package 100 is in direct contact with the ambient atmospheric pressure (step 504) as described above with reference to FIG. 3. In step 504, vacuum pump 214 draws air from package 100 through closure element 112 and feeds it into conduit 212.

[0029] Step 506 monitors the profile of the test exhaust pressure. A timer of test system 200 is triggered and the exhaust period begins. The exhaust pressure is detected by pressure sensor 216 and monitored by controller 218.

[0030] When a predetermined exhaust period ends, step 508 determines whether there is a leak in the package. The predetermined exhaust period can be any length of time suitable for testing package 100. For example, the predetermined exhaust period can be the first predetermined period 406, the second predetermined period 416, the third predetermined period 422, or the fourth predetermined period 428. Step 508 includes determining whether there is a leak in package 100 based on a comparison of the profile of the test exhaust pressure with the reference pressure profile of a reference package without leaks as described above with reference to FIG. 4.

[0031] Step 508 may include determining that there is no leak in package 100 when the deviation between the profile of the test exhaust pressure (e.g., test exhaust profile 410) and the profile 400 of the reference exhaust pressure is within the first predetermined threshold 408 within the first predetermined period 406. Step 408 may include determining that there is a leak between the closure material 112 and the coupling element 202 (e.g., gasket 210) and that there is no leak in package 100 when the profile 412 of the test exhaust pressure exceeds the profile 400 of the reference exhaust pressure and exceeds the second predetermined threshold 414 within the second predetermined period 416 (however, does not exceed the third predetermined threshold 420). Step 508 may include determining that there is a leak in package 100 when the profile 418 of the test exhaust pressure exceeds the profile 400 of the reference exhaust pressure and exceeds the third predetermined threshold 420 within the third predetermined period 422. Step 508 may include determining that there is a pinhole in the closure element 112 when the profile 424 of the test exhaust pressure is below the profile 400 of the reference exhaust pressure and exceeds the fourth predetermined threshold 426 within the fourth predetermined period 428.

[0032] FIG. 6 shows another embodiment of a coupling element 600 for use in test system 200. In this example, the coupling element 600 includes a seat 602 sized and shaped to receive package 100 and stably hold the package during a leak test process. Similar to the coupling element 202 of FIG. 2, this coupling element 600 defines an air flow path 605 and, together with package 100, enables an air flow path as described above with reference to FIG. 3.

[0033] FIGS. 7A and 7B show additional examples of structures for coupling package 100 to test system 200. In these examples, the coupling element includes a suction cup 700 that enables an air flow path from package 100 directly to a conduit 212 within system 200. As shown in FIG. 7A, cup 700 is attached directly to closure element 112 on package 100. As shown in FIG. 7B, a gasket 702 is interposed between suction cup 700 and closure element 112.

[0034] Figures 8A and 8B show additional examples of structures for coupling package 100 to test system 200. Package 100 is made of a flexible material having a first surface 120 and a second surface 122 on the opposite side of the first surface 120. Storage volume 105 is surrounded by the first surface 120 and the second surface 122. Opening 103 is located within the second surface 122 and is surrounded by the first surface 120 and the second surface 122.

[0035] The first surface 120 is made of a non-gas-permeable material 124. The second surface 122 is made of both the non-gas-permeable material 124 and the gas-permeable material of the closure element 112. The gas-permeable material of the closure element 112 reaches over the entire area above the opening 103, and the adhesive joint 116 attaches the gas-permeable material of the closure element 112 to the body 102 of the package 100 adjacent to the opening 103.

[0036] Coupling element 800 includes a suction cup 802 and a sheet 804 of gas-permeable material. The sheet 804 of gas-permeable material can be removably attached to the second surface 122 of the package 100 to form a continuous contact with the gas-permeable material of the closure element 112. The sheet 804 of gas-permeable material can be made of silicone and can keep the package 100 substantially flat during the leak test.

[0037] As shown in Figure 8A, the suction cup 802 is attached to the sheet 804 of gas-permeable material. Alternatively, as shown in Figure 8B, the suction cup 802 can be connected to a port 803 fused to the sheet of gas-permeable material 804. During the leak test, the package 100 can be placed on a relatively flat surface / support, and the suction cup 802 is placed in contact with the package 100, allowing an air flow path from the package 100 through the gas-permeable material of the closure element 112 and through the sheet 804 of gas-permeable material to the conduit 212 of the system 200. The suction cup 802 is large enough to at least surround the opening 103.

[0038] This specification shows the best mode for carrying out the invention described in the claims, and by presenting examples of the elements described in the claims, explains the invention so that those skilled in the art can carry out and use the invention. A detailed description of these examples does not impose limitations not described in the claims.

Claims

1. A system for performing a leak test on a package having a body with an opening, a gas permeable material covering the entire area of the opening, and an adhesive bonding portion for attaching the gas permeable material to the body adjacent to the opening, a coupling element connected to the package and configured to allow a potential leakage air flow path into the coupling element, the potential leakage air flow path being a) a flow path from inside the package through the opening and further through the gas permeable material, and b) a flow path from the surrounding atmosphere into the package and further through the gas permeable material including the coupling element, a vacuum pump operably connected to the coupling element to apply a test exhaust pressure to the leakage air flow path, a pressure sensor operative to sense the test exhaust pressure within the coupling element, a controller, monitoring a profile of the test exhaust pressure within the coupling element, comparing the profile of the test exhaust pressure with a profile of a reference exhaust pressure of a leak-free reference package, and determining whether there is a leak in the package based on the comparison configured as such, the controller and a system comprising.

2. The system according to claim 1, wherein the controller is configured to determine that there is no leak in the package when a deviation between the profile of the test exhaust pressure and the profile of the reference exhaust pressure is within a first predetermined threshold within a first predetermined period.

3. The system according to claim 1, wherein the controller is configured to determine that there is a leak between the gas permeable material and the coupling element and there is no leak in the body of the package when the profile of the test exhaust pressure exceeds the profile of the reference exhaust pressure and exceeds a second predetermined threshold within a second predetermined period.

4. The system according to claim 1, wherein the controller is configured to determine that there is a leak in the package when the profile of the test exhaust pressure exceeds the profile of the reference exhaust pressure and exceeds a third predetermined threshold within a third predetermined period.

5. The system according to claim 1, wherein the controller is configured to determine that there is a pinhole in the gas permeable material when the profile of the test exhaust pressure is below the profile of the reference exhaust pressure and exceeds a fourth predetermined threshold within a fourth predetermined period.

6. The system according to claim 1, wherein the coupling element is further configured to enable a potential leakage gas flow path to the coupling element from the ambient atmosphere into the package and further through the gas permeable material adjacent to the opening.

7. The system according to claim 1, wherein the coupling device includes a gasket configured to be disposed between the conduit and the gas permeable material adjacent to the opening.

8. The system according to claim 1, wherein the coupling device includes a gas permeable material sheet removably attached to the gas permeable material and configured to keep the package relatively flat during the leak test.

9. A method for performing a leak test on a package having a body with an opening, a gas permeable material covering the entire area of the opening, and an adhesive bonding portion attaching the gas permeable material to the body adjacent to the opening, comprising: coupling a vacuum system to the package to enable a potential leakage air flow path into the vacuum system, the potential leakage air flow path including: a) a flow path from inside the package through the opening and further through the gas permeable material; and b) a flow path from the ambient atmosphere into the package and further through the gas permeable material ; operating the vacuum system to apply a test exhaust pressure to the leakage air flow path; monitoring a profile of the test exhaust pressure; and determining whether there is a leak in the package based on a comparison of the profile of the test exhaust pressure with a profile of a reference exhaust pressure of a leak-free reference package .

10. The method according to claim 8, further comprising determining that there is no leak in the package when a deviation between the profile of the test exhaust pressure and the profile of the reference exhaust pressure is within a first predetermined threshold within a first predetermined period.

11. The method according to claim 8, further comprising the step of determining that there is a leak between the gas permeable material and the bonding element when the profile of the test exhaust pressure exceeds the profile of the reference exhaust pressure and exceeds a second predetermined threshold within a second predetermined period, and there is no leak in the body of the package.

12. The method according to claim 8, further comprising the step of determining that there is a leak in the package when the profile of the test exhaust pressure exceeds the profile of the reference exhaust pressure and exceeds a third predetermined threshold within a third predetermined period.

13. The method according to claim 8, comprising the step of determining that there is a pinhole in the gas permeable material when the profile of the test exhaust pressure is lower than the profile of the reference exhaust pressure and exceeds a fourth predetermined threshold within a fourth predetermined period.

14. The step of coupling the vacuum system to the package allows a potential leak air flow path from the ambient atmosphere into the package and further into the vacuum system through the gas permeable material adjacent to the opening, according to the method of claim 8.

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