Method of detecting gas leakage and apparatus for detecting gas leakage

Abstract

Detects gas leakage of the test specimen accurately in a short time. A method for detecting gas leakage of a test specimen (W) comprises the steps of: sealing the test specimen (W) into the internal space (IS2) of a chamber (CH); introducing a first gas into the internal space (IS1) of the test specimen (W) to raise the pressure in the internal space (IS1) of the test specimen (W) higher than the pressure in the internal space (IS2) of the chamber (CH); vacuuming the internal space (IS1) of the test specimen (W); introducing a second gas into the internal space (IS2) of the chamber (CH); and performing a second leakage test to detect gas leakage of the test specimen (W) by detecting the second gas that has flowed from the internal space (IS2) of the chamber (CH) into the internal space (IS1) of the test specimen (W).

Description

Technology Field

[0001] The present invention relates to a method for detecting gas leakage and a detection device. Background Technology

[0002] The airtightness of vacuum vessels, gas storage containers, etc., is tested by detecting gas leakage from these containers. Known methods for detecting gas leakage include the bell jar method, the sniffer method, and the vacuum hood method.

[0003] The Bell method is a method for detecting gas leakage in a test specimen by sealing a container (referred to as a test specimen) subject to airtightness testing into an internal space of a container such as a chamber, introducing tracer gas into the internal space of the test specimen, and detecting the inflow of tracer gas from the internal space of the test specimen into the internal space of the chamber. The sniffer method is a method for detecting gas leakage in a test specimen by introducing tracer gas into the internal space of the test specimen, bringing a tracer gas detection device close to a location where gas leakage of the test specimen is likely to occur, and detecting tracer gas leaked from the internal space of the test specimen to the outside by the detection device.

[0004] The vacuum hood method is a method for detecting gas leakage in a test specimen by sealing the test specimen within the internal space of a container, such as a chamber, vacuuming the internal space of the test specimen, introducing tracer gas into the internal space of the chamber, etc., and detecting the inflow of tracer gas from the chamber, etc. into the test specimen.

[0005] Recently, the use of a gas containing hydrogen gas as the aforementioned tracer gas is being considered. In addition, a detection device (leakage detector) capable of detecting hydrogen gas contained in the tracer gas has been known (see, for example, Patent Document 1). This detection device ionizes the hydrogen gas contained in the tracer gas to generate hydrogen ions, and detects the hydrogen gas by detecting the generated hydrogen ions. Prior art literature

[0006] Japanese Patent Publication No. 2023-109360 The problem to be solved

[0007] Conventional gas leak detection methods described above have problems, such as the inability to detect gas leaks within a short time or to detect leaks accurately. Specifically, in the Bell Jar method, particularly when using a gas containing hydrogen as a tracer gas, if molecules containing hydrogen elements, such as moisture, are present in the internal space where the tracer gas is introduced (e.g., a chamber), hydrogen ions are generated from these molecules within the detection device. Since these hydrogen ions become a significant background, it becomes impossible to properly determine whether hydrogen ions originating from the tracer gas have been detected. As a result, it is not possible to accurately detect whether a leak exists in the test specimen.

[0008] To remove the aforementioned molecules present in an internal space such as a chamber, one might consider vacuuming the internal space. However, in order to reduce the amount of hydrogen ions generated from the aforementioned molecules to a level negligible compared to the amount of hydrogen ions generated from the tracer gas and to stabilize the background signal, it is necessary to vacuum a large-capacity internal space such as a chamber for an extended period. As a result, it takes time to detect gas leakage in the test specimen.

[0009] In the sniffer method, particularly when there are multiple locations where gas leakage is likely to occur in the test specimen, it is necessary to repeat the process of approaching each location to check for tracer gas leakage multiple times, so it takes time to detect gas leakage in the test specimen.

[0010] In the vacuum hood method, particularly when the test specimen is a container that stores gas in its internal space, when the internal space of the test specimen is vacuumed or when tracer gas is introduced into the internal space of a chamber, the direction of pressure applied to the test specimen (pressure in the direction in which the test specimen contracts) becomes opposite to the direction of pressure applied during normal use of the test specimen (pressure in the direction in which the test specimen expands). Consequently, coatings, plating films, liquids, dust, or fragments of the test specimen attached to the surface of the test specimen, or cracks in the test specimen, may block gaps, cracks, and / or through holes in the test specimen. Since the blockage of gaps, cracks, and through holes makes it difficult for tracer gas to flow into the internal space of the test specimen, there is a possibility of misjudging that there is no gas leakage when there should originally be a gas leakage.

[0011] In addition, in the vacuum hood method, tracer gas is introduced into the internal space of a chamber filled with air, so the tracer gas and air mix, and the concentration of tracer gas in the internal space of the chamber decreases. For this reason, even if tracer gas present in the internal space of the chamber flows into the internal space of the test specimen, the tracer gas is not clearly detected by the detection device, so it is not possible to clearly detect whether there is a gas leak in the test specimen. This problem becomes particularly pronounced when a gas containing hydrogen gas is used as the tracer gas and gas leaks are detected by detecting hydrogen gas. This is because, for safety reasons, the concentration of hydrogen gas contained in the tracer gas is kept low to a few percent, and the concentration of hydrogen gas drops further when this tracer gas mixes with air.

[0012] The objective of the present invention is to resolve the aforementioned problems of conventional gas leakage detection methods and to accurately detect gas leakage in a test specimen in a short period of time. means of solving the problem

[0013] Below, a plurality of embodiments are described as means for solving the problem. These embodiments may be arbitrarily combined as needed. A method for detecting gas leakage of a test specimen according to one embodiment of the present invention comprises the following steps.

[0014] (a) A step of sealing the test specimen into the internal space of the chamber.

[0015] (b) A step of introducing a first gas into the internal space of the test specimen to raise the pressure in the internal space of the test specimen higher than the pressure in the internal space of the chamber.

[0016] (c) A step of vacuuming the internal space of the test specimen.

[0017] (d) A step of introducing a second gas into the internal space of the chamber.

[0018] (e) A step of performing a second leak test to detect gas leakage of the test specimen by detecting a second gas that has flowed from the internal space of the chamber into the internal space of the test specimen.

[0019] A method for detecting gas leakage of a test specimen according to another aspect of the present invention is a method for detecting gas leakage of a test specimen using hydrogen gas, and comprises the following steps.

[0020] (a) A step of sealing the test specimen into the internal space of the chamber.

[0021] (b) A step of vacuuming the internal space of the test specimen and the internal space of the chamber.

[0022] (c) A step of introducing a second gas containing hydrogen gas into the internal space of the chamber.

[0023] (d) A step of detecting gas leakage of a test specimen by detecting hydrogen gas contained in a second gas that has flowed from the internal space of the chamber into the internal space of the test specimen. Effects of the invention

[0024] In the above-described method for detecting gas leakage, before vacuuming the internal space of the test specimen to perform the above-described second leakage test, a first gas is introduced into the internal space of the test specimen to raise the pressure in the internal space of the test specimen higher than the pressure in the internal space of the chamber. By raising the pressure in the internal space of the test specimen higher than the pressure in the internal space of the chamber before performing the second leakage test, when vacuuming the internal space of the test specimen during the second leakage test, it becomes difficult for gaps, cracks, through holes, etc., in the test specimen to be blocked by the coating film, plating film, liquid, dust, test specimen fragments, etc. of the test specimen. As a result, gas leakage in the test specimen can be detected without being overlooked during the second leakage test.

[0025] In addition, in the method for detecting gas leakage of a test specimen using the aforementioned hydrogen gas, the internal space of the chamber is vacuumed before introducing a second gas containing hydrogen gas into the internal space of the chamber to detect gas leakage of the test specimen. As a result, since air is discharged from the internal space of the chamber before introducing the second gas containing hydrogen gas into the internal space of the chamber, mixing of the second gas and air does not occur when the second gas is introduced into the internal space of the chamber, and thus the concentration of hydrogen gas in the internal space of the chamber does not decrease further. As a result, since the hydrogen gas contained in the second gas flowing from the internal space of the chamber into the internal space of the test specimen can be clearly detected, it is possible to clearly detect whether or not there is gas leakage in the test specimen. Brief explanation of the drawing

[0026] Figure 1 is a diagram illustrating the configuration of a gas leak detection device. Figure 2 is a flowchart illustrating a method for detecting gas leakage of a test specimen. Figure 3 is a flowchart illustrating the process of the first leakage test. FIG. 4 is a diagram illustrating an example of pressure change in the internal space of a test specimen after the first gas is introduced into the internal space of the test specimen. Figure 5 is a flowchart illustrating the process of the second leakage test. FIG. 6 is a flowchart illustrating another embodiment of a method for detecting gas leakage. FIG. 7 is a flowchart illustrating another embodiment of a method for detecting gas leakage. Specific details for implementing the invention

[0027] (1) Gas leak detection device

[0028] Hereinafter, a gas leak detection device (100) according to one embodiment will be described with reference to the drawings. The gas leak detection device (100) is a device for detecting gas leaks in a test specimen (W). The test specimen (W) is, for example, a container (e.g., a condenser) for storing and holding gas (e.g., refrigerant gas) in an air conditioner, etc., or gas piping used in an air conditioner, etc. In such a test specimen (W), if gaps, cracks, and / or through holes exist in the main body of the test specimen (W) or in the connection parts between members, gas leaks from the internal space (IS1) to the outside through these gaps, cracks, and through holes. The gas leak detection device (100) detects gas leaks in the test specimen (W) by detecting the inflow / outflow of gas from / to the internal space (IS1) of the test specimen (W) through the gaps, cracks, and through holes present in the test specimen (W).

[0029] In the gas leak detection device (100), a first gas is introduced into the internal space (IS1) of the test body (W) to raise the pressure in the internal space (IS1) higher than that outside the test body (W), and a leak test (referred to as the first leak test) is performed to detect gas leakage of the test body (W) by detecting the outflow of the first gas from the internal space (IS1) to the outside, and a leak test (referred to as the second leak test) is performed to detect gas leakage of the test body (W) by detecting the second gas that has flowed into the internal space (IS1) from the outside when the internal space (IS1) of the test body (W) is vacuumed and then a second gas (tracer gas) is supplied to the outside of the test body (W).

[0030] In the first leak test, an inert gas such as nitrogen or argon, air, etc., may be used as the first gas. In this embodiment, the first gas is nitrogen. Meanwhile, in the second leak test, a mixed gas of an inert gas such as nitrogen gas and hydrogen gas may be used as the second gas. In this embodiment, the second gas is a mixed gas in which hydrogen gas is mixed with nitrogen gas in an amount of several percent.

[0031] Hereinafter, the configuration of a gas leak detection device (100) is described using FIG. 1. FIG. 1 is a drawing illustrating the configuration of a gas leak detection device (100). The gas leak detection device (100) comprises a chamber (CH), a first gas inlet (1), a first exhaust (2), a pressure gauge (3), a second gas inlet (4), a second exhaust (5), and a second gas detection device (6).

[0032] A chamber (CH) is a member having an internal space (IS2), an opening connected to the internal space (IS2), and a cover portion that blocks the opening. A test specimen (W) can be placed in the internal space (IS2) through the opening of the chamber (CH), and the test specimen (W) can be sealed in the internal space of the chamber (CH) by blocking the opening with the cover portion.

[0033] The first gas introduction section (1) introduces the first gas into the internal space (IS1) of the test specimen (W). The first gas introduction section (1) has a first gas pipe (11) and a first gas supply section (13). The first gas pipe (11) is connected to the internal space (IS1) of the test specimen (W), which is placed in the internal space (IS2) of the chamber (CH), so as to enable gas flow. Specifically, the first gas pipe (11) is connected to the opening of the test specimen (W) by a connecting member (T), such as a test port, for example. That is, the first gas pipe (11) is detachably connected to the test specimen (W).

[0034] The first gas supply unit (13) is a device including a cylinder or the like that supplies the first gas. The first gas supply unit (13) is connected to the first gas pipe (11) through the first valve (15).

[0035] In the first gas introduction section (1) described above, by opening the first valve (15), the first gas supplied from the first gas supply section (13) is introduced into the internal space (IS1) of the test specimen (W) through the first gas pipe (11). Meanwhile, by closing the first valve (15), the introduction of the first gas into the internal space (IS1) of the test specimen (W) can be stopped.

[0036] The first gas inlet (1) additionally has a first discharge line (17). One end of the first discharge line (17) is connected to an external space. Meanwhile, the other end of the first discharge line (17) is connected to the first gas pipe (11), for example, through a second valve (19). By opening the second valve (19), the internal space (IS1) of the test specimen (W) and the external space are connected through the first discharge line (17), so that the first gas introduced into the internal space (IS1) can be discharged to the external space.

[0037] The first exhaust section (2) vacuums the internal space (IS1) of the test specimen (W) and the second gas detection device (6). The first exhaust section (2) has a second gas pipe (21), a first vacuum pump (22), a second vacuum pump (23), a third vacuum pump (24), a third valve (25), a fourth valve (26), a fifth valve (27), a fourth vacuum pump (31), and a sixth valve (32).

[0038] The second gas pipe (21) is connected to the internal space (IS1) of the test specimen (W) placed in the internal space (IS2) of the chamber (CH) to enable gas flow. Specifically, the second gas pipe (21) is connected to the opening of the test specimen (W) by a connecting member (T), such as a test port. That is, the second gas pipe (21) is detachably connected to the test specimen (W).

[0039] The suction side of the first vacuum pump (22) is connected to the second gas pipe (21) through the third valve (25). Additionally, the suction side of the first vacuum pump (22) is connected to the exhaust side of the second vacuum pump (23) through the fourth valve (26). The first vacuum pump (22) is, for example, an oil rotary pump.

[0040] The suction side of the second vacuum pump (23) is connected to the exhaust side of the third vacuum pump (24) through the third gas pipe (28). Additionally, the suction side of the second vacuum pump (23) is connected to the second gas pipe (21) through the third gas pipe (28) and the fifth valve (27). The second vacuum pump (23) is, for example, a screw groove pump. The suction side of the third vacuum pump (24) is connected to the second gas detection device (6). The third vacuum pump (24) is, for example, a turbo molecular pump.

[0041] The suction side of the fourth vacuum pump (31) is connected to the second gas pipe (21) through the sixth valve (32). The fourth vacuum pump (31) is, for example, an oil rotary pump.

[0042] In the first exhaust section (2), the first vacuum pump (22) is operated to close the fourth valve (26) and the fifth valve (27) and open the third valve (25), thereby vacuuming the internal space (IS1) of the test specimen (W) by the first vacuum pump (22). If the volume of the test specimen (W) is large, the fourth vacuum pump (31) is operated to open the sixth valve (32), thereby vacuuming the interior of the test specimen (W).

[0043] In addition, by operating the first vacuum pump (22), the second vacuum pump (23), and the third vacuum pump (24), the third valve (25) and the fifth valve (27) are closed and the fourth valve (26) is opened, the second gas detection device (6) can be vacuumed to a high vacuum by the third vacuum pump (24).

[0044] Additionally, by operating the first vacuum pump (22), the second vacuum pump (23), and the third vacuum pump (24), the third valve (25) is closed and the fourth valve (26) and the fifth valve (27) are opened, so that some of the gas in the internal space (IS1) of the test specimen (W) passes through (backflows) the third vacuum pump (24) and flows into the second gas detection device (6). The remainder of the gas in the internal space (IS1) of the test specimen (W) is sucked in by the second vacuum pump (23).

[0045] The pressure gauge (3) is detachably connected to the opening of the test body (W) by a connecting member (T), such as a test port, for example. The pressure gauge (3) measures the pressure in the internal space (IS1) of the test body (W). The pressure gauge (3) is, for example, a pressure sensor. As described below, during the first leak test, after introducing the first gas into the internal space (IS1) of the test body (W), the pressure in the internal space (IS1) is measured by the pressure gauge (3). If a decrease in pressure is observed in the internal space (IS1) of the test body (W), it can be determined that there is a gas leak in the test body (W).

[0046] The second gas introduction unit (4) is connected to the internal space (IS2) of the chamber (CH) to enable gas flow, thereby introducing the second gas into the internal space (IS2) of the chamber (CH). The second gas introduction unit (4) includes a device for supplying the second gas.

[0047] The second exhaust section (5) vacuums the internal space (IS2) of the chamber (CH). The second exhaust section (5) has a fourth gas pipe (51) and a fifth vacuum pump (53). The fourth gas pipe (51) is connected to the chamber (CH) to enable gas flow through the internal space (IS2) of the chamber (CH). The suction side of the fifth vacuum pump (53) is connected to the fourth gas pipe (51) through the seventh valve (55). The fifth vacuum pump (53) is, for example, an oil rotary pump, a mechanical dry pump, etc.

[0048] In the second exhaust section (5), the fifth vacuum pump (53) is operated to open the seventh valve (55), thereby allowing the internal space (IS2) of the chamber (CH) to be vacuumed by the fifth vacuum pump (53).

[0049] The second gas detection device (6) is introduced into the internal space (IS2) of the chamber (CH) and is a device for detecting the second gas that flows from the internal space (IS2) of the chamber (CH) into the internal space (IS1) of the test specimen (W). As described above, in this embodiment, the second gas is a mixed gas of nitrogen gas and hydrogen gas. Therefore, in this embodiment, the second gas detection device (6) is a device for detecting hydrogen gas contained in the second gas.

[0050] The second gas detection device (6) is a device having, for example, an ion source unit that ionizes hydrogen gas contained in the second gas introduced from the internal space (IS1) of the test specimen (W) through the first exhaust unit (2) to generate hydrogen ions, and an ion collector unit (for example, including an ion collection device) that detects hydrogen gas contained in the second gas by detecting the generated hydrogen ions. This second gas detection device (6) can detect hydrogen gas contained in the second gas with high sensitivity.

[0051] In addition, for example, a gas sensor capable of detecting hydrogen gas contained in the second gas introduced from the internal space (IS1) of the test specimen (W) through the first exhaust section (2) may be used as the second gas detection device (6).

[0052] The gas leak detection device (100) may additionally be provided with a chamber leak line (7). The chamber leak line (7) leaks into the internal space (IS2) of the chamber (CH). Specifically, one end of the chamber leak line (7) is connected to the external space. Meanwhile, the other end of the chamber leak line (7) is connected to the internal space (IS2) of the chamber (CH), for example, through the eighth valve (71).

[0053] By opening the eighth valve (71), air from the atmosphere can be introduced into the internal space (IS2) of the chamber (CH) through the chamber leak line (7), or gas can be discharged from the internal space (IS2) of the chamber (CH) to bring the internal space (IS2) to atmospheric pressure. After bringing the internal space (IS2) to atmospheric pressure, the test specimen (W) placed in the internal space (IS2) can be removed.

[0054] (2) Method for detecting gas leaks

[0055] Hereinafter, using FIG. 2, a method for detecting gas leakage of a test specimen (W) using a gas leakage detection device (100) having the above-described configuration will be explained. FIG. 2 is a flowchart illustrating a method for detecting gas leakage of a test specimen (W).

[0056] First, a test specimen (W) to be detected for gas leakage is connected to a connecting member (T) of a gas leakage detection device (100). By doing so, the internal space (IS1) of the test specimen (W) is connected to the first gas pipe (11) of the first gas inlet section (1), the second gas pipe (21) of the first exhaust section (2), and the pressure gauge (3) so that gas can flow through them. After that, the test specimen (W) connected to the connecting member (T) is placed in the internal space (IS2) of the chamber (CH) through the opening of the chamber (CH) and sealed (Step S1).

[0057] After sealing the test specimen (W) in the internal space (IS2) of the chamber (CH), a first leakage test is performed (step S2). The first leakage test is performed according to the flowchart shown in FIG. 3. FIG. 3 is a flowchart illustrating the process of the first leakage test.

[0058] First, the first valve (15) of the first gas inlet (1) of the gas leak detection device (100) is opened. By doing so, the first gas supplied from the first gas supply unit (13) passes through the first gas pipe (11) and is introduced into the internal space (IS1) of the test body (W) (Step S21). As the first gas is introduced into the internal space (IS1) of the test body (W), the internal space (IS1) is pressurized, and the pressure in the internal space (IS1) of the test body (W) becomes higher than the pressure in the internal space (IS2) of the chamber (CH) (e.g., atmospheric pressure).

[0059] In this way, by making the pressure in the internal space (IS1) of the test specimen (W) higher than the pressure in the internal space (IS2) of the chamber (CH), the coating, plating film, liquid, dust, and test specimen fragments of the test specimen (W) that are blocking the gaps, cracks, and through holes of the test specimen (W) are blown away, thereby clearing the blockage of cracks and through holes of the test specimen (W) before the second leakage test is performed, and ensuring that cracks and through holes are not blocked even when the internal space (IS1) of the test specimen (W) is vacuumed.

[0060] At this time, it is desirable to make the difference between the pressure in the internal space (IS1) of the test specimen (W) and the pressure in the internal space (IS2) of the chamber (CH) as large as possible. By making the pressure difference between the internal space (IS1) of the test specimen (W) and the internal space (IS2) of the chamber (CH) large, the first gas can flow easily through gaps, cracks, and through holes in the test specimen (W), thereby causing a clear pressure change in the internal space (IS1) of the test specimen (W) (the internal space (IS2) of the chamber (CH)). That is, based on the pressure change in the internal space (IS1) of the test specimen (W), it becomes easier to detect gas leakage of the test specimen (W).

[0061] In addition, it is desirable that the pressure difference between the internal space (IS1) of the test specimen (W) and the internal space (IS2) of the chamber (CH) be equal to or close to the pressure difference between the internal space (IS1) of the test specimen (W) and the outside that occurs when the test specimen (W) is actually used. By doing so, it becomes easier to detect gas leakage that may occur when the test specimen (W) is actually used.

[0062] In addition, it is desirable to make the pressure difference between the internal space (IS1) of the test specimen (W) and the internal space (IS2) of the chamber (CH) greater than the pressure difference that occurs when the internal space (IS1) of the test specimen (W) is vacuumed, for example, in a second leakage test that may be performed later. As a result, even if the internal space (IS1) of the test specimen (W) is vacuumed in the second leakage test, it becomes difficult for the coating film, plating film, liquid, dust, test specimen fragments, etc. of the test specimen (W) to block gaps, cracks, or through holes of the test specimen (W).

[0063] This is because, by setting the pressure difference between the internal space (IS1) of the test body (W) and the internal space (IS2) of the chamber (CH) as described above, when a first gas is introduced into the internal space (IS1) of the test body (W) and pressurized, the coating, plating film, liquid, dust, and test body fragments of the test body (W) can be blown away with a force greater than the force caused by the pressure difference when the internal space (IS1) of the test body (W) is vacuumed. In addition, since the gaps, cracks, and through holes of the test body (W) can be widened with a force greater than the force caused by the pressure difference when vacuumed, it is possible to prevent the gaps, cracks, and through holes from being blocked again when the test body (W) is vacuumed.

[0064] Taking the above into account, the pressure in the internal space (IS1) of the test specimen (W) can be, for example, several atmospheres or more by introducing the first gas into the internal space (IS1). This pressure can be appropriately changed depending on the type of test specimen (W), etc. In addition, the pressure in the internal space (IS1) of the test specimen (W) can be measured using a pressure gauge (3).

[0065] A first gas is introduced into the internal space (IS1) of the test specimen (W) to raise the pressure in the internal space (IS1) of the test specimen (W) higher than the pressure in the internal space (IS2) of the chamber (CH), and then the first valve (15) of the first gas introduction part (1) is closed to stop the introduction of the first gas into the internal space (IS1) of the test specimen (W) (Step S22).

[0066] After stopping the introduction of the first gas into the internal space (IS1) of the test specimen (W), the pressure in the internal space (IS1) of the test specimen (W) is measured by the pressure gauge (3) (step S23).

[0067] The pressure in the internal space (IS1) after the first gas is introduced into the internal space (IS1) of the test specimen (W) changes over time as shown in FIG. 4. FIG. 4 is a diagram illustrating an example of the pressure change in the internal space (IS1) after the first gas is introduced into the internal space (IS1) of the test specimen (W).

[0068] Specifically, when the first gas is introduced, the internal space (IS1) of the test specimen (W) rises from an initial pressure P1 (e.g., atmospheric pressure) to a predetermined pressure P2 (e.g., several atmospheres or more). Then, when the introduction of the first gas is stopped after time t1 has elapsed since the introduction of the first gas, if there is a gas leak in the test specimen (W), the first gas leaks out from the internal space (IS1) of the test specimen (W) into the internal space (IS2) of the chamber (CH), so the pressure in the internal space (IS1) of the test specimen (W) decreases over time, and the pressure in the internal space (IS2) of the chamber (CH) increases over time. Furthermore, if there is no gas leak, the first gas does not leak out from the internal space (IS1) of the test specimen (W) into the internal space (IS2) of the chamber (CH), so the pressure in the internal space (IS1) of the test specimen (W) becomes nearly constant at P2.

[0069] After that, when the pressure in the internal space (IS1) of the test specimen (W) and the internal space (IS2) of the chamber (CH) becomes equal, the outflow of the first gas is stopped, and the internal space (IS1) of the test specimen (W) (and the internal space (IS2) of the chamber (CH)) becomes constant at pressure P3. Pressure P3 is determined by the pressure (P2) after the introduction of the first gas, the initial pressure of the internal space (IS2) of the chamber (CH) (e.g., atmospheric pressure), the volume of the internal space (IS1) of the test specimen (W), the volume of the internal space (IS2) of the chamber (CH), etc.

[0070] After stopping the introduction of the first gas, it may take time for the internal space (IS1) of the test specimen (W) to become constant. In particular, as indicated by the dotted line in FIG. 4, when the gas leakage of the test specimen (W) is small and the pressure change in the internal space (IS1) of the test specimen (W) is small, the pressure may not become constant indefinitely.

[0071] Accordingly, as a result of the pressure change (decrease) in the internal space (IS1) of the test specimen (W), the pressure in the internal space (IS1) of the test specimen (W) reaches a predetermined threshold P within a predetermined time (t2-t1 in the example of FIG. 4). TH If it drops to, and / or pressure ratio P TH If / P2 becomes less than or equal to a predetermined value ("Yes" in Step S24), it is determined that there is a gas leak in the test specimen (W) (Step S25). Threshold P TH is, for example, a pressure P3 or higher at which the outflow of the first gas stops, and a pressure smaller than the pressure P2 after the introduction of the first gas (P3≤P TH <P2)으로 할 수 있다.

[0072] Meanwhile, the pressure in the internal space (IS1) of the test specimen (W) reaches a predetermined threshold P within a predetermined time (t2-t1 in the example of FIG. 4). TH If not lowered to, and / or pressure ratio P THIf / P2 does not become less than or equal to a predetermined value ("No" in Step S24), it is determined that there is no gas leakage in the test specimen (W) (Step S26).

[0073] As described above, in the first leak test, gas leakage of the test specimen (W) can be detected based on the pressure change of the internal space (IS1) of the test specimen (W) after the first gas is introduced. In the first leak test, since operations such as vacuuming the internal space (IS1) of the test specimen (W) and the internal space (IS2) of the chamber (CH) and gas replacement are unnecessary, gas leakage of the test specimen (W) can be detected in a short time.

[0074] Returning to the description of FIG. 2. If, as a result of the first leak test described above, it is determined that there is a gas leak in the test specimen (W) ("Yes" in Step S3), the detection of the gas leak using the gas leak detection device (100) is terminated. In this way, if it is determined that there is a gas leak in the test specimen (W) during the first leak test, the detection of the gas leak in the test specimen (W) can be completed in a short time without conducting a second leak test.

[0075] When the detection of gas leakage is completed in the first leakage test, the second valve (19) of the first gas inlet (1) is opened to discharge the first gas into the atmosphere from the internal space (IS1) of the test body (W) through the first gas pipe (11) and the first discharge line (17), thereby bringing the internal space (IS1) of the test body (W) to atmospheric pressure. Additionally, the eighth valve (71) is opened to discharge the first gas that has flowed into the internal space (IS2) of the chamber (CH) through the chamber leak line (7) into the atmosphere, thereby bringing the internal space (IS2) of the chamber (CH) to atmospheric pressure. After that, the test body (W) is removed from the internal space (IS2) of the chamber (CH) to the outside, and the test body (W) is detached from the connecting member (T).

[0076] Meanwhile, if it is determined that there is no gas leakage in the test specimen (W) as a result of the first leakage test ("No" in Step S3), a second leakage test is performed (Step S4). The second leakage test is performed according to the flowchart shown in FIG. 5. FIG. 5 is a flowchart illustrating the process of the second leakage test.

[0077] The second gas detection device (6) is vacuumed and is always in a high vacuum (Step S41). Specifically, in the first exhaust section (2), the third valve (25) and the fifth valve (27) are closed, the fourth valve (26) is opened, and the first vacuum pump (22), the second vacuum pump (23), and the third vacuum pump (24) are operated so that the interior of the second gas detection device (6) (location of the ion source section and ion collector section) is vacuumed to a high vacuum.

[0078] After that, the internal space (IS1) of the test specimen (W) and the internal space (IS2) of the chamber (CH) are vacuumed (step S42). Specifically, the internal space (IS1) of the test specimen (W) is vacuumed by the first vacuum pump (22) by closing the fourth valve (26) and the fifth valve (27) of the first exhaust unit (2) and opening the third valve (25). After that, the internal space (IS1) of the test specimen (W) is vacuumed by the second vacuum pump (23) by closing the third valve (25) of the first exhaust unit (2) and opening the fourth valve (26) and the fifth valve (27).

[0079] When the volume of the test specimen (W) is large, the fourth vacuum pump (31) is first operated to open the sixth valve (32) and vacuum the internal space (IS1) of the test specimen (W). Then, the third valve (25) of the first exhaust unit (2) is closed, and the fourth valve (26) and fifth valve (27) are opened, so that the internal space (IS1) of the test specimen (W) is further vacuumed by the second vacuum pump (23).

[0080] In addition, the fifth vacuum pump (53) of the second exhaust unit (5) is operated to open the seventh valve (55), thereby vacuuming the internal space (IS2) of the chamber (CH) by the fifth vacuum pump (53) and discharging the gas (e.g., air) inside the internal space (IS2).

[0081] During this vacuuming process, hydrogen ions are generated from the ion source section within the second gas detection device (6), and the hydrogen ions generated from the ion source section are detected by the ion collector section. When the exhaust of the test specimen (W) is initiated, if residual gas (water molecules, hydrocarbon molecules) exists in the internal space (IS1) of the test specimen (W), this residual gas is introduced into the second gas detection device (6). Even though the second gas is not introduced into the second gas detection device (6), hydrogen ions are generated due to the residual gas, and hydrogen ions are detected. As a result, the detection signal (i.e., background signal) obtained when the second gas is not introduced into the second gas detection device (6) becomes larger. If the background signal is large, when the second gas is introduced into the second gas detection device (6), the detection signal caused by the second gas is buried in the background signal, making it impossible to clearly detect the detection signal caused by the second gas. Here, "clear" refers to a state in which a detection signal attributable to the second gas can be recognized by distinguishing it from the background signal.

[0082] In addition, if residual gas remains during vacuuming of the internal space (IS1) of the test specimen (W), the remaining residual gas continues to flow into the interior of the second gas detection device (6), so the background signal continues to fluctuate (decrease), and the fluctuation of the detection signal caused by the second gas is offset by the fluctuation of the background signal, so the detection signal caused by the second gas cannot be clearly detected.

[0083] Meanwhile, when residual gas is sufficiently removed from the internal space (IS1) by vacuuming the internal space (IS1) of the test specimen (W), the background signal stabilizes at a small value. By stabilizing the background signal at a small value, the detection signal attributed to hydrogen gas contained in the second gas can be clearly detected. That is, in step S42, the internal space (IS1) of the test specimen (W) is vacuumed to remove residual gas until the background signal is sufficiently degraded and stabilized to the extent that the detection signal attributed to the second gas can be distinguished and recognized.

[0084] As described above, after vacuuming the internal space (IS1) of the test specimen (W) and the internal space (IS2) of the chamber (CH), a second gas is introduced into the internal space (IS2) of the chamber (CH) by the second gas introduction part (4) (step S43).

[0085] If there is a gas leak in the test specimen (W), the second gas introduced into the internal space (IS2) of the chamber (CH) flows into the internal space (IS1) of the test specimen (W). A portion of the second gas flowing into the internal space (IS1) of the test specimen (W) passes through the third vacuum pump (24) (backflow) and flows into the interior of the second gas detection device (6). The remaining second gas is sucked in by the second vacuum pump (23).

[0086] The hydrogen gas contained in the second gas that has flowed into the interior of the second gas detection device (6) is ionized in the internal ion source section of the second gas detection device (6). The hydrogen ions generated in the ion source section are detected by the ion collector section. That is, when the second gas detection device (6) detects hydrogen ions caused by the hydrogen gas contained in the second gas ("Yes" in Step S44), it can be determined that the second gas has flowed into the internal space (IS1) of the test specimen (W) and that there is a gas leak (Step S45).

[0087] Meanwhile, if the second gas detection device (6) does not detect hydrogen ions ("No" in step S44), it is determined that there is no gas leakage because the second gas is not introduced into the internal space (IS1) of the test specimen (W) (step S46).

[0088] After the second leak test is completed, the third valve (25) and the fifth valve (27) of the first exhaust unit (2) are closed to stop vacuuming the internal space (IS1) of the test specimen (W) by the first exhaust unit (2), and the seventh valve (55) of the second exhaust unit (5) is closed to stop vacuuming the internal space (IS2) of the chamber (CH) by the second exhaust unit (5).

[0089] Next, the second valve (19) of the first gas inlet (1) is opened to introduce air into the internal space (IS1) of the test specimen (W) in a negative pressure state through the first discharge line (17), thereby bringing the internal space (IS1) of the test specimen (W) to atmospheric pressure. Additionally, the eighth valve (71) is opened to introduce air into the internal space (IS2) of the chamber (CH) in a negative pressure state through the chamber leak line (7), thereby bringing the internal space (IS2) of the chamber (CH) to atmospheric pressure. After that, the test specimen (W) is removed from the internal space (IS2) of the chamber (CH) to the outside, and the test specimen (W) is detached from the connecting member (T).

[0090] As described above, in the second leak test, a gas containing hydrogen gas is used as the second gas serving as the tracer gas. Since hydrogen molecules are small and have the property of penetrating small gaps, the second leak test can detect the presence or absence of small gas leaks that could not be detected in the first leak test. In other words, by combining the first leak test and the second leak test, gas leaks of the test specimen (W), including even small ones, can be detected in a short period of time.

[0091] As described above, in the method for detecting gas leakage using a gas leakage detection device (100), before vacuuming the internal space (IS1) of the test body (W) to perform a second leakage test, a first gas is introduced into the internal space (IS1) of the test body (W) to make the pressure in the internal space (IS1) of the test body (W) higher than the pressure in the internal space (IS2) of the chamber (CH). By making the pressure in the internal space (IS1) of the test body (W) higher than the pressure in the internal space (IS2) of the chamber (CH) before performing the second leakage test, when vacuuming the internal space (IS1) of the test body (W) during the second leakage test, cracks, through holes, etc. of the test body (W) are less likely to be blocked by the coating film, plating film, liquid, dust, test body fragments, etc. of the test body (W).

[0092] For example, the coating, plating film, liquid, dust, and specimen fragments of the test specimen (W) that are blocking the gaps, cracks, and through holes of the test specimen (W) can be blown away by making the pressure in the internal space (IS1) of the test specimen (W) higher than the pressure in the internal space (IS2) of the chamber (CH), thereby clearing the blockage of the cracks and through holes of the test specimen (W) before the second leakage test is performed, and ensuring that the cracks and through holes are not blocked even when the internal space (IS1) of the test specimen (W) is vacuumed.

[0093] In addition, as in the present embodiment, when the internal space (IS1) of the test specimen (W) is in a pressurized state during normal use, the direction of the pressure applied to the test specimen (W) is the direction in which the test specimen (W) expands. On the other hand, when the internal space (IS1) of the test specimen (W) is vacuumed for the second leakage test, the direction of the pressure applied to the test specimen (W) is the direction in which the test specimen (W) contracts. That is, when the internal space (IS1) of the test specimen (W) is vacuumed, pressure is generated in the test specimen (W) in the opposite direction to that during normal use. Due to this reverse pressure, the coating film, plating film of the test specimen (W), liquids, dust attached to the surface of the test specimen (W), and test specimen fragments from cracked parts of the test specimen (W) may block cracks, through holes, etc. that are open during normal use.

[0094] Therefore, by making the pressure in the internal space (IS1) of the test specimen (W) higher than the pressure in the internal space (IS2) of the chamber (CH) before the second leak test, pressure in the same direction as during normal use is applied to the test specimen (W), so that cracks and through holes that are open during normal use are reliably kept open before the second leak test, and so that they are not blocked even when the internal space (IS1) of the test specimen (W) is vacuumed.

[0095] As described above, by making the pressure in the internal space (IS1) of the test specimen (W) higher than the pressure in the internal space (IS2) of the chamber (CH) before the second leak test, cracks, penetration holes, etc. of the test specimen (W) that cause gas leakage can be reliably opened before the second leak test, so that gas leakage of the test specimen (W) can be detected without being overlooked during the second leak test.

[0096] In addition, in a second leak test in which a second gas containing hydrogen gas is used as a tracer gas, the internal space (IS2) of the chamber (CH) is vacuumed before introducing the second gas containing hydrogen gas into the internal space (IS2) of the chamber (CH) to detect gas leakage of the test specimen (W). As a result, air is discharged from the internal space (IS2) of the chamber (CH), so when the second gas is introduced into the internal space (IS2) of the chamber (CH), no mixing of the second gas and air occurs, and thus the concentration of hydrogen gas in the internal space (IS2) of the chamber (CH) does not decrease further. As a result, the hydrogen gas contained in the second gas introduced from the internal space (IS2) of the chamber (CH) into the internal space (IS1) of the test specimen (W) can be clearly detected, and thus it is possible to clearly detect whether there is gas leakage in the test specimen (W).

[0097] Although an embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications are possible within the scope of not departing from the gist of the invention. In particular, the plurality of embodiments and variations described herein may be arbitrarily combined as needed.

[0098] The execution details of each step and the execution order of each step in the flowcharts illustrated in FIGS. 2, FIGS. 3, and FIGS. 5 can be changed at will.

[0099] For example, the first leak test may be omitted. In this case, the pressure gauge (3) in the gas leak detection device (100) may be omitted. Specifically, as shown in FIG. 6, the test specimen (W) is sealed in the internal space (IS2) of the chamber (CH) (step S51), the first gas is introduced into the internal space (IS1) of the test specimen (W) to raise the pressure in the internal space (IS1) of the test specimen (W) higher than the pressure in the internal space (IS2) of the chamber (CH) (step S52), and the introduction of the first gas into the internal space (IS1) of the test specimen (W) is stopped (step S53). After that, vacuuming the interior of the second gas detection device (6) (step S54), vacuuming the interior space (IS1) of the test specimen (W) and the interior space (IS2) of the chamber (CH) (step S55), and introducing the second gas into the interior space (IS2) of the chamber (CH) (step S56) are performed, and when the second gas is detected ("Yes" in step S57), it is determined that there is a leak in the test specimen (W) (step S58), and when the second gas is not detected ("No" in step S57), it is determined that there is no leak in the test specimen (W) (step S59). FIG. 6 is a flowchart illustrating another embodiment of the method for detecting gas leaks.

[0100] The operations in steps S51 to S59 of the flowchart of FIG. 6 are, respectively, identical to the operations in steps S1, S21 to S22, and S41 to S46 described above. Therefore, a detailed description of the operations in steps S51 to S59 is omitted.

[0101] Before vacuuming the internal space (IS1) of the test specimen (W) to perform a leak test using the second gas, the first gas is introduced into the internal space (IS1) of the test specimen (W) to raise the pressure in the internal space (IS1) of the test specimen (W) higher than the pressure in the internal space (IS2) of the chamber (CH). Consequently, when the internal space (IS1) of the test specimen (W) is vacuumed during the leak test using the second gas, gaps, cracks, and through holes in the test specimen (W) become difficult to block by the coating, plating film, liquid, dust, or other debris of the test specimen. As a result, gas leakage in the test specimen (W) can be detected without being overlooked during the leak test using the second gas.

[0102] For example, the introduction of the first gas into the internal space (IS1) of the test specimen (W) and the execution of the first leak test may be omitted. In this case, the first gas introduction part (1) (specifically, the first gas supply part (13), the first valve (15)) and the pressure gauge (3) in the gas leak detection device (100) may be omitted. Specifically, as illustrated in FIG. 7, a test specimen (W) is sealed in the internal space (IS2) of a chamber (CH) (Step S61), vacuuming the interior of the second gas detection device (6) (Step S62), vacuuming the internal space (IS1) of the test specimen (W) and the internal space (IS2) of the chamber (CH) (Step S63), and introducing a second gas containing hydrogen gas into the internal space (IS2) of the chamber (CH) (Step S64). When hydrogen gas contained in the second gas is detected ("Yes" in Step S65), it is determined that there is a leak in the test specimen (W) (Step S66), and when hydrogen gas contained in the second gas is not detected ("No" in Step S65), it is determined that there is no leak in the test specimen (W) (Step S67). FIG. 7 is a flowchart illustrating another embodiment of a method for detecting gas leaks.

[0103] The operations in steps S61 to S67 of the flowchart of FIG. 7 are, respectively, identical to the operations in steps S1 and S41 to S46 described above. Therefore, a detailed description of the operations in steps S61 to S67 is omitted.

[0104] In the above-described detection method, the internal space (IS2) of the chamber (CH) is vacuumed before introducing a second gas containing hydrogen gas into the internal space (IS2) of the chamber (CH) to detect gas leakage of the test specimen (W) using hydrogen gas. As a result, air is discharged from the internal space (IS2) of the chamber (CH) before introducing the second gas containing hydrogen gas into the internal space (IS2) of the chamber (CH). Therefore, when the second gas is introduced into the internal space (IS2) of the chamber (CH), no mixing of the second gas and air occurs, and thus the concentration of hydrogen gas in the internal space (IS2) of the chamber (CH) does not decrease further. As a result, hydrogen gas contained in the second gas introduced from the internal space (IS2) of the chamber (CH) into the internal space (IS2) of the test specimen (W) can be clearly detected, and thus, whether or not there is gas leakage in the test specimen (W) can be clearly detected using hydrogen gas.

[0105] In addition to the pressure gauge (3) for measuring the pressure in the internal space (IS1) of the test specimen (W), or instead thereof, a pressure gauge for measuring the pressure in the internal space (IS2) of the chamber (CH) may be provided. In this case, during the first leak test, if an increase in the pressure in the internal space (IS2) of the chamber (CH) is observed by the pressure gauge for measuring the pressure in the internal space (IS2) of the chamber (CH) after the first gas is introduced into the internal space (IS1) of the test specimen (W), it can be determined that there is a gas leak in the test specimen (W).

[0106] Helium may be used as the second gas used in the second leak test. The second gas detection device (6), having an ion source unit that ionizes hydrogen gas to generate hydrogen ions and an ion collector unit that detects the generated hydrogen ions, can be used even when the second gas is made of helium after setting it to ionize helium to detect helium ions.

[0107] In the above-described gas leak detection device (100), a device for performing a first leak test (first gas inlet (1), pressure gauge (3)) and a device for performing a second leak test (first exhaust (2), second gas inlet (4), second exhaust (5), second gas detection device (6)) were integrated into a single device. However, this is not limited to this, and the device for performing the first leak test and the device for performing the second leak test may be separate devices.

[0108] The gas leak detection method described above may be automatically executed by a control device that controls the gas leak detection device (100). This control device is a computer system composed of, for example, a computing device such as a CPU, a memory device (for example, RAM, ROM, HDD, SSD, etc.), and various interfaces. The control device may automatically execute the gas leak detection method described above by executing a program stored in the memory device.

[0109] It is understood by those skilled in the art that the above-described exemplary embodiments are specific examples of the following modes.

[0110] (First embodiment) A method for detecting gas leakage of a test specimen (e.g., test specimen (W)) comprises the following steps. The following (a) to (e) do not limit the order of execution of each step.

[0111] (a) A step of enclosing the test specimen in the internal space (e.g., internal space (IS2)) of a chamber (e.g., chamber (CH)). (e.g., step S1, S51).

[0112] (b) a step of introducing a first gas into the internal space of the test specimen (e.g., internal space (IS1)) to raise the pressure in the internal space of the test specimen higher than the pressure in the internal space of the chamber (e.g., steps S21, S52).

[0113] (c) A step of vacuuming the internal space of the test specimen (e.g., steps S42, S55).

[0114] (d) A step of introducing a second gas into the internal space of the chamber (e.g., steps S43, S56).

[0115] (e) A step of performing a second leak test to detect gas leakage of the test specimen by detecting a second gas flowing from the internal space of the chamber into the internal space of the test specimen (e.g., steps S44 to S46, S57 to S59).

[0116] In the method for detecting gas leakage according to the first embodiment, before vacuuming the internal space of the test specimen to perform a second leakage test, a first gas is introduced into the internal space of the test specimen, thereby making the pressure in the internal space of the test specimen higher than the pressure in the internal space of the chamber. By making the pressure in the internal space of the test specimen higher than the pressure in the internal space of the chamber before performing the second leakage test, when vacuuming the internal space of the test specimen during the second leakage test, it becomes difficult for gaps, cracks, through holes, etc., in the test specimen to be blocked by the coating film, plating film, liquid, dust, test specimen fragments, etc. of the test specimen. As a result, gas leakage in the test specimen can be detected without being overlooked during the second leakage test.

[0117] (Second embodiment) The method for detecting gas leakage according to the first embodiment may additionally include a step (e.g., step S2, steps S21 to S26) for introducing a first gas into the internal space of the test specimen to raise the pressure in the internal space of the test specimen higher than the pressure in the internal space of the chamber, and then performing a first leakage test to detect gas leakage of the test specimen based on the pressure change in the internal space of the test specimen or the internal space of the chamber. In the method for detecting gas leakage according to the second embodiment, operations such as vacuuming the internal space of the test specimen and the internal space of the chamber, and gas exchange are unnecessary, so gas leakage of the test specimen can be detected in a short time.

[0118] (Third embodiment) In the method for detecting gas leakage according to the second embodiment, the step of vacuuming the internal space of the test specimen, the step of introducing a second gas into the internal space of the chamber, and the step of performing a second leakage test do not need to be performed if gas leakage of the test specimen is detected in the first leakage test. In the method for detecting gas leakage according to the third embodiment, gas leakage of the test specimen can be detected in a short time without performing a second leakage test.

[0119] (Fourth embodiment) In the method for detecting gas leakage according to any of the first to third embodiments, the step of introducing the second gas into the internal space of the chamber may be performed after the internal space of the chamber has been vacuumed. In the method for detecting gas leakage according to the fourth embodiment, since air is discharged from the internal space of the chamber before the second gas is introduced into the internal space of the chamber, no mixing of the second gas and air occurs when the second gas is introduced into the internal space of the chamber. As a result, the second gas flowing from the internal space of the chamber into the internal space of the test specimen can be clearly detected, and thus, whether or not there is a gas leakage in the test specimen can be clearly detected.

[0120] (Fifth embodiment) In the method for detecting gas leakage of any of the first to fourth embodiments, the second gas may include hydrogen gas. In this case, the second leakage test may be performed by detecting hydrogen gas contained in the second gas that has flowed from the internal space of the chamber into the internal space of the test specimen. In the method for detecting gas leakage according to the fifth embodiment, since hydrogen gas having the property of being able to penetrate into small gaps is used in the second leakage test, the presence or absence of small gas leakage of the test specimen (W) can be detected.

[0121] (Sixth embodiment) A method for detecting gas leakage of a test specimen using hydrogen gas comprises the following steps. The following (a) to (d) do not limit the order of execution of each step.

[0122] (a) A step of sealing the test specimen into the internal space of the chamber (e.g., steps S1, S61).

[0123] (b) A step of vacuuming the internal space of the test specimen and the internal space of the chamber (e.g., steps S42, S63).

[0124] (c) A step of introducing a second gas containing hydrogen gas into the internal space of the chamber (e.g., steps S43, S64).

[0125] (d) A step for detecting gas leakage of a test specimen by detecting hydrogen gas contained in the second gas introduced from the internal space of the chamber into the internal space of the test specimen (e.g., steps S44 to S46, S65 to S67).

[0126] In the method for detecting gas leakage according to the sixth embodiment, the internal space of the chamber is vacuumed before introducing a second gas containing hydrogen gas into the internal space of the chamber to detect gas leakage of a test specimen. As a result, since air is discharged from the internal space of the chamber before introducing the second gas containing hydrogen gas into the internal space of the chamber, mixing of the second gas and air does not occur when the second gas is introduced into the internal space of the chamber, and thus the concentration of hydrogen gas in the internal space of the chamber is not further reduced. As a result, hydrogen gas contained in the second gas introduced from the internal space of the chamber into the internal space of the test specimen can be clearly detected, and thus it is possible to clearly detect whether gas leakage exists in the test specimen.

[0127] (Seventh embodiment) A gas leak detection device (e.g., a gas leak detection device (100)) comprises a chamber, a first gas inlet (e.g., a first gas inlet (1)), an exhaust (e.g., a first exhaust (2)), a second gas inlet (e.g., a second gas inlet (4)), and a second gas detection device (e.g., a second gas detection device (6)). The chamber encloses a test specimen in its internal space. The first gas inlet introduces a first gas into the internal space of the test specimen, thereby increasing the pressure in the internal space of the test specimen to be higher than the pressure in the internal space of the chamber. The first exhaust creates a vacuum in the internal space of the test specimen. The second gas inlet introduces a second gas into the internal space of the chamber. The second gas detection device detects the second gas that has flowed from the internal space of the chamber into the internal space of the test specimen.

[0128] In the gas leakage detection device according to the seventh embodiment, before vacuuming the internal space of the test specimen to perform a second leakage test, a first gas is introduced into the internal space of the test specimen to raise the pressure in the internal space of the test specimen higher than the pressure in the internal space of the chamber. By raising the pressure in the internal space of the test specimen higher than the pressure in the internal space of the chamber before performing the second leakage test, when vacuuming the internal space of the test specimen during the second leakage test, it becomes difficult for gaps, cracks, through holes, etc., in the test specimen to be blocked by the coating film, plating film, liquid, dust, test specimen fragments, etc. of the test specimen. As a result, gas leakage in the test specimen can be detected without being overlooked during the second leakage test.

[0129] (Eighth embodiment) A gas leak detection device comprises a chamber, an exhaust section (e.g., a first exhaust section (2), a second exhaust section (5)), a second gas introduction section, and a second gas detection device. The chamber encloses a test specimen in its internal space. The exhaust section vacuums the internal space of the test specimen and the internal space of the chamber. The second gas introduction section introduces a second gas containing hydrogen gas into the internal space of the chamber. The second gas detection device detects hydrogen gas contained in the second gas introduced from the internal space of the chamber into the internal space of the test specimen.

[0130] In the gas leakage detection device according to the eighth embodiment, the internal space of the chamber is vacuumed before introducing a second gas containing hydrogen gas into the internal space of the chamber to detect gas leakage of a test specimen. As a result, since air is discharged from the internal space of the chamber before introducing the second gas containing hydrogen gas into the internal space of the chamber, mixing of the second gas and air does not occur when the second gas is introduced into the internal space of the chamber, and thus the concentration of hydrogen gas in the internal space of the chamber is not further reduced. As a result, hydrogen gas contained in the second gas introduced from the internal space of the chamber into the internal space of the test specimen can be clearly detected, and thus it is possible to clearly detect whether gas leakage exists in the test specimen. Explanation of the symbols

[0131] 100: Gas leak detection device W: Test specimen IS1: Interior space CH: Chamber IS2: Interior space T: Connection failure 1: First gas inlet 11: 1st Gas Pipeline 13: 1st Gas Supply Unit 15: First valve 17: 1st discharge line 19: Second valve 2: First exhaust section 21: Second Gas Pipeline 22: First vacuum pump 23: Second vacuum pump 24: Third vacuum pump 25: Third valve 26: 4th valve 27: 5th valve 28: 3rd Gas Pipeline 31: 4th vacuum pump 32: 6th valve 3: Pressure gauge 4: Second gas inlet 5: Second exhaust section 51: 4th Gas Pipeline 53: 5th vacuum pump 55: 7th valve 6: Second gas detection device 7: Chamber leak line 71: 8th valve

Claims

Claim 1 A method for detecting gas leakage of a test specimen, comprising the steps of: sealing the test specimen in the internal space of a chamber; introducing a first gas into the internal space of the test specimen to raise the pressure in the internal space of the test specimen higher than the pressure in the internal space of the chamber; vacuuming the internal space of the test specimen; introducing a second gas into the internal space of the chamber; and performing a second leakage test to detect gas leakage of the test specimen by detecting the second gas that has flowed from the internal space of the chamber into the internal space of the test specimen. Claim 2 A method for detecting gas leakage according to claim 1, further comprising the step of introducing a first gas into the internal space of the test specimen to raise the pressure in the internal space of the test specimen to a higher level than the pressure in the internal space of the chamber, and then performing a first leakage test to detect gas leakage in the test specimen based on a pressure change in the internal space of the test specimen or the internal space of the chamber. Claim 3 A method for detecting gas leakage according to paragraph 2, wherein the step of vacuuming the internal space of the test specimen, the step of introducing the second gas into the internal space of the chamber, and the step of performing the second leakage test are not performed when gas leakage of the test specimen is detected in the first leakage test. Claim 4 A method for detecting gas leakage according to claim 1, wherein the step of introducing the second gas into the internal space of the chamber is performed after vacuuming the internal space of the chamber. Claim 5 A method for detecting gas leakage according to claim 1, wherein the second gas comprises hydrogen gas, and the second leakage test is performed by detecting the hydrogen gas included in the second gas introduced from the internal space of the chamber into the internal space of the test specimen. Claim 6 A method for detecting gas leakage of a test specimen using hydrogen gas, comprising the steps of: sealing the test specimen in the internal space of a chamber; vacuuming the internal space of the test specimen and the internal space of the chamber; introducing a second gas containing the hydrogen gas into the internal space of the chamber; and detecting the gas leakage of the test specimen by detecting the hydrogen gas contained in the second gas introduced from the internal space of the chamber into the internal space of the test specimen. Claim 7 A device for detecting gas leakage of a test specimen, comprising: a chamber for sealing the test specimen in an internal space; a first gas inlet for introducing a first gas into the internal space of the test specimen to raise the pressure in the internal space of the test specimen higher than the pressure in the internal space of the chamber; an exhaust for vacuuming the internal space of the test specimen; a second gas inlet for introducing a second gas into the internal space of the chamber; and a second gas detection device for detecting the second gas that has flowed from the internal space of the chamber into the internal space of the test specimen. Claim 8 A gas leak detection device comprising: a chamber for sealing the test specimen in an internal space; an exhaust unit for vacuuming the internal space of the test specimen and the internal space of the chamber; a second gas introduction unit for introducing a second gas containing the hydrogen gas into the internal space of the chamber; and a second gas detection device for detecting the hydrogen gas contained in the second gas introduced from the internal space of the chamber into the internal space of the test specimen.

Images