Carrier gas leak detection system and carrier gas leak detection method for detecting leaks in test specimens

Abstract

A system and method for detecting leaks in a test specimen by detecting carrier gas leaks, which allows for the adjustment of the flow rate of the carrier gas in a gas detector and the pressure in a test chamber without requiring any technical effort. A carrier gas leak detection system (10) for detecting leaks in a test specimen includes a gas detector (12), a test chamber (20) having at least a first test chamber inlet (22), a test chamber outlet (26), and a test chamber vacuum pump (27) for evacuating the test chamber outlet (26), a first gas line (28) for gas-conductively connecting the test chamber outlet (26) to the detector space inlet (15) and the test chamber vacuum pump (27), and further includes a second flow restrictor (D2) for presetting the flow rate of the carrier gas passing through the first test chamber inlet (22), and a second gas line (30) for connecting the test chamber outlet (26) to the test chamber vacuum pump (27) in parallel with the first gas line (28), The gas line 28 and the second gas line 30 are connected to a test chamber vacuum pump 27 at a first connection point 38 so that gas can be conducted through the second gas line 30, a third flow restrictor D3 in a detector section 40 between the first connection point 38 of the first gas line 28 and the detector space inlet 15, and a fourth flow restrictor D4 in the second gas line 30 between the test chamber outlet 26 and the first connection point 38, the third flow restrictor D3 and the fourth flow restrictor D4 being provided as flow dividing means so that a first branch flow passing through the first gas line 28 and a second branch flow passing through the second gas line 30 can be evacuated from the test chamber 20 by the test chamber vacuum pump 27.

Description

[Technical Field]

[0001] The present invention relates to a system and method for leak detection in a specimen. [Background technology]

[0002] In comprehensive leak testing using test gas, a test specimen is inspected in a test chamber by vacuum leak detection of the test gas. For this purpose, a test specimen filled with test gas is placed in the test chamber, which is then evacuated. A test gas detector measures the partial pressure of the test gas in the vacuum system. Test gas flowing into the test chamber from the leak in the test specimen can be actively guided to the test gas detector by a carrier gas. For this purpose, carrier gas is continuously introduced into the test chamber while being evacuated by the vacuum system, so that the operating pressure in the test chamber is at equilibrium. The resulting carrier gas flow carries the test gas leaking from the test specimen to the test gas detector. The presence or absence of a signal and its measured intensity are measures of the leak rate of the test specimen. Various detectors are used to detect the test gas, depending on the required detection limit. To achieve extremely high test gas sensitivity, a quadrupole mass spectrometer is used. A QMS offers both high sensitivity and high selectivity.

[0003] In principle, the carrier gas approach can also be applied with other types of detectors, such as optical detectors or area sensors, which do not necessarily need to operate in vacuum or high vacuum. Summary of the Invention [Problem to be solved by the invention]

[0004] The optimum total pressure of the ion source, 1E-4 mbar, provides the highest sensitivity. Lower operating pressures in the detection chamber reduce the number of molecules or atoms available for detection, while higher operating pressures result in loss of charge carriers due to space charge effects. If the density of charged particles in the ion source chamber is too high, the charge carriers repel each other too strongly.

[0005] The optimum operating pressure is achieved by keeping the suction volume of the QMS detection volume constant and the conductance of the pressure transducer inlet (e.g., capillary) constant to obtain a predetermined inlet pressure. If the inlet pressure deviates from the optimum value, it will generally have a quadratic effect on the total pressure of the ion source.

[0006] For example, if the inlet pressure is reduced by half, the total pressure in the high vacuum will be reduced to one-quarter of its original value. As the ion source pressure decreases, the system sensitivity decreases. In other words, any change in pressure at the mass spectrometer inlet will disproportionately reduce the system sensitivity.

[0007] In the carrier gas method, the flow rate of the carrier gas is adjusted to match the amount of gas present in the test chamber, with the goal of replacing the gas volume in the chamber by a factor of approximately 2-3 (tau) in the shortest possible time to achieve a convergence of the leak signal.

[0008] In principle, it is possible to maintain a lower pressure in the test chamber in order to exchange less gas, but this would mean that it would take longer to evacuate the chamber and the cost of the evacuation system would be higher.

[0009] Therefore, the carrier gas flow rate must be increased for larger test chambers (larger net chamber volumes) and decreased for smaller net volumes.

[0010] As the carrier gas flow rate changes, the equilibrium pressure in the test chamber also changes.

[0011] In particular, in the case of quadrupole mass spectrometers, it is desirable to adjust the operating pressure of a gas detector (e.g., the detector space of a mass spectrometer gas detector) to the changing operating pressure in the test chamber. This also applies to other types of detectors. The operating pressure in the test chamber varies depending on the amount of carrier gas introduced into the test chamber and the suction volume of the pump used to evacuate the test chamber. Hereinafter, such a pump will be referred to as the test chamber vacuum pump. Adjusting the operating pressure of the detector or detector space by the suction volume of the vacuum pump would require considerable technical effort and is therefore not practical. Hereinafter, the vacuum pump that evacuates the detector space in the case of a vacuum detector will be referred to as the detector vacuum pump.

[0012] In view of the above background, an object of the present invention is to provide a system and method for detecting leaks in a test specimen by detecting carrier gas leaks, which allows for the adjustment of the flow rate of the carrier gas in the gas detector and the pressure in the test chamber without any technical effort. [Means for solving the problem]

[0013] A leak detection system according to the present invention is defined by the features of claim 1. A leak detection method according to the present invention is defined by the features of claim 13.

[0014] The carrier gas leak detection system according to the present invention includes a gas detector and a test chamber. The test chamber has a test chamber space. At least a first test chamber inlet and a test chamber outlet open into the test chamber space. A test chamber vacuum pump that draws a vacuum in the test chamber space is connected to the test chamber outlet. The test chamber outlet is connected to the gas detector and the test chamber vacuum pump by a first gas line so as to supply the gas to be analyzed from the test chamber to the gas detector.

[0015] The gas detector may include a detector space inlet. The detector space inlet may include a first flow restrictor for pressure transduction at the detector space inlet. The first flow restrictor may be, for example, a suitable cross-sectional shape of the detector space inlet. Depending on the type of detector, the first flow restrictor may not be necessary. A second flow restrictor is provided at the test chamber inlet to supply carrier gas into the test chamber space. The conductance of the second flow restrictor may be adjustable to change the flow rate of the carrier gas.

[0016] A second gas line connecting the test chamber outlet to the gas detector in parallel with the first gas line is connected to the test chamber vacuum pump and the first gas line at a first connection point so as to allow gas to flow therethrough. A third flow restrictor is provided in the detector section of the first gas line between the first connection point and the gas detector. A fourth flow restrictor is provided in the second gas line between the test chamber outlet and the first connection point. In other words, the third flow restrictor and the fourth flow restrictor constitute a flow dividing means in cooperation with the first and second gas lines so that a first branch flow passing through the second gas line and a second branch flow passing through the first gas line can be evacuated from the test chamber by the test chamber vacuum pump.

[0017] The third flow restrictor is provided in the first gas line between the first flow restrictor and the test chamber vacuum pump to adjust the pressure of the first gas line. The conductance of the third flow restrictor may be adjustable. The third flow restrictor may provide a preset pressure for the gas detector, or may be selectively adjusted manually or automatically by a pressure control device. The second flow restrictor may specify or change the flow rate of the carrier gas supplied to the test chamber.

[0018] A fourth flow restriction is provided in the second gas line between the test chamber outlet and the test chamber vacuum pump. The fourth flow restriction can specify or adjust the suction rate at which the test chamber vacuum pump draws carrier gas into the test chamber volume. The test chamber vacuum pump is connected to the first and second gas lines at the first connection point between the third flow restriction and the fourth flow restriction so that a primary flow of carrier gas flows through the second flow restriction and the test chamber inlet into the test chamber volume and from the test chamber outlet through the fourth flow restriction to the test chamber vacuum pump. The test chamber suction rate specified by the fourth flow restriction, in conjunction with the third flow restriction, determines the pressure within the test chamber for a given flow rate of carrier gas.

[0019] For example, the conductance of the fourth flow restrictor may also be adjustable to vary and / or selectively adjust the carrier gas flow rate and / or pressure within the test chamber either manually or automatically via a pressure control device.

[0020] The first and / or second and / or third and / or fourth flow restrictions each determine the gas conductance of their respective line cross sections and may be specified, for example, by opening, capillary, conductance, cross-sectional area, diameter, etc. of each cross section of the gas line.

[0021] In the present invention, the third and fourth flow restrictors can divide the gas flow drawn from the test chamber by the test chamber vacuum pump. That is, the third and fourth flow restrictors constitute a flow dividing means. One branch, hereinafter referred to as the first branch, proceeds directly to the test chamber vacuum pump along the first gas line, while the other branch, hereinafter referred to as the second branch, proceeds past the gas detector along the first gas line to the test chamber vacuum pump. When a leak occurs in the test piece, the second branch, which contains the test gas, supplies carrier gas to the detector for analysis there. In the case of a vacuum detector or high-vacuum detector, such as a mass spectrometer, in which the detector space is evacuated, the detector space typically continues to be evacuated by the detector vacuum pump during this time.

[0022] The present invention allows for leak detection of a specimen within a test chamber by adjusting the flow rate of a carrier gas that carries the leaking or test gas from the test chamber to a detector and selectively adjusting the pressure ratio and volume of gas within the detector and test chamber as required.

[0023] A corresponding method of carrier gas leak detection for leak detection of a test specimen according to the present invention comprises: introducing a specimen into the test chamber; drawing a vacuum in the test chamber with the test chamber vacuum pump; supplying a carrier gas through the second flow restrictor into the test chamber containing the test specimen; drawing a vacuum through the first and second gas lines with the test chamber vacuum pump; specifying or adjusting the conductance of the third flow restrictor and the fourth flow restrictor as flow dividing means so that the first divided flow passing through the second gas line and the second divided flow passing through the first gas line can be evacuated from the test chamber by the test chamber vacuum pump; analyzing gas from the second branch with the gas detector; The present invention is characterized by comprising:

[0024] Preferably, the flow rate of gas along the first branch is greater, in particular significantly greater, than the flow rate of gas along the second branch. The flow rates of gas along the first and second branches are specified by the third and fourth flow restrictors and can be adjusted if the conductances of the flow restrictors are variable. Preferably, the conductance S3 of the third restrictor is lower, in particular significantly lower, than the conductance S4 of the fourth restrictor. Preferably, the conductances S3 and S4 can be set, for example, manually or by an electronic control device.

[0025] Advantageously, the first gas line includes a first selectively closable valve in a test chamber section between the test chamber outlet and the gas detector or detector space inlet, and the detector section includes a second selectively closable valve between the first flow restrictor and the third flow restrictor. The first and second valves allow constant pressure conditions to be maintained while the test chamber is being evacuated by the test chamber vacuum pump. Closing the first and second valves allows the test chamber to be directly connected to the test chamber to evacuate it without changing the pressure at the detector space inlet during the evacuation of the test chamber.

[0026] The test chamber inlet may be provided with a selectively closable third valve.

[0027] The test chamber may comprise at least one second test chamber inlet used for venting or flushing the test chamber or the test chamber space, the second test chamber inlet comprising a selectively closable fourth valve that is opened only during venting or flushing.

[0028] In particular, the test chamber outlet may be directly connected to the test chamber vacuum pump by a third gas line. Preferably, the third gas line straddles the second gas line, which includes the fourth flow restrictor and an optional sixth valve located upstream of the fourth flow restrictor. The third gas line may be provided with a selectively closable fifth valve. When the fifth valve is opened, the test chamber is evacuated directly via the third gas line, e.g., after introducing a test specimen into the test chamber, to bring the test chamber to the required test chamber vacuum pressure. Advantageously, the test chamber vacuum pressure is a few millibars, e.g., in the range of 0.1 to 10 mbar. Thereafter, the fifth valve is closed and the sixth valve is opened, so that the test chamber vacuum pump continues to deliver a carrier gas flow through the test chamber space to the second gas line when the third valve is opened. The sixth valve may be opened beforehand, e.g., when the test chamber is evacuated via the third gas line, or the sixth valve may not be present.

[0029] The second gas line, including the fourth flow restrictor and the sixth valve, extends in parallel with the third gas line, including the fifth valve. When the first, second, third, and fourth valves are closed, the fifth valve is opened, allowing the test chamber vacuum pump to directly evacuate the test chamber through the third gas line. When the required test chamber pressure is reached, the fifth valve is closed and the third valve is opened. As a result, carrier gas is drawn into the test chamber space through the first test chamber inlet, passes through the open sixth valve and the fourth flow restrictor, along the second gas line, and is supplied to the test chamber vacuum pump. Meanwhile, the gas detector can be evacuated by the gas detector vacuum pump.

[0030] To start leak measurement, the first and second valves are opened. This causes a branch flow of carrier gas, hereinafter referred to as the second branch flow, to be supplied along the first gas line and along the detector section of the test chamber vacuum pump, past the gas detector. The third and fourth flow restrictors determine the flow rate division ratio. The first branch flow flows through the second gas line to the test chamber vacuum pump. If there is leakage gas from the test specimen, the carrier gas containing the leakage gas from the second branch flow, which is guided along the first gas line past the gas detector, can reach or enter the gas detector and be detected there.

[0031] The gas detector may be a vacuum gas detector or a mass spectrometric gas detector having a detector space with a detector space inlet and a detector space outlet. A detector vacuum pump is connected to the detector space outlet to evacuate the detector space to the required vacuum pressure. Alternatively, the gas detector may be another type of detector, such as an optical detector, an emission or emission absorption detector, or a surface sensor through which a carrier gas flow is directed. In the case of a mass spectrometric gas detector, the detector may be a quadrupole mass spectrometer. In this specification, the term "vacuum gas detector" refers to any type of detector that generally requires a vacuum for gas detection, such as a mass spectrometric gas detector. A detector vacuum pump separate from the test chamber vacuum pump may be provided to generate the vacuum required for the vacuum gas detector. The detector vacuum pump may be a high-vacuum pumping system including a high-vacuum pump, such as a turbomolecular pump, for evacuating the detector space and a pre-vacuum pump for evacuating the high-vacuum pump.

[0032] A first pressure gauge for measuring the pressure in the test chamber section of the first gas line may be connected between the first valve and the first flow restrictor. A second pressure gauge for measuring the pressure in the detector section of the first gas line may be connected between the first connection point and the third flow restrictor. Flow restrictors D3, D4 and / or valves V1, V2, V6 may be controlled in response to the measured pressure.

[0033] Preferably, the test chamber is connected to a third pressure gauge that measures the pressure in the test chamber, and the second throttle D2 and / or the fourth throttle D4 and / or the third valve V3 and / or the fourth valve V4 and / or the fifth valve V5 and / or the sixth valve V6 can be controlled depending on the measured pressure in the test chamber.

[0034] Two exemplary embodiments of the present invention will now be described in detail with reference to the drawings, each of which is a schematic diagram of a carrier gas leak detection system. [Brief explanation of the drawings]

[0035] [Figure 1] 1 is a schematic diagram illustrating an exemplary embodiment of a carrier gas leak detection system. [Figure 2] FIG. 10 is a schematic diagram illustrating a carrier gas leak detection system according to another exemplary embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0036] 1 is a mass spectrometric carrier gas leak detection system including a mass spectrometric gas detector 12 in the form of a quadrupole mass spectrometer having a detector space 14, a detector space inlet 15 opening into the detector space 14, and a detector space outlet 16 opening into the detector space 14. A detector vacuum pump 18 is connected to the detector space outlet 16, which evacuates the detector space 14. The detector vacuum pump 18 comprises a turbomolecular pump and a pre-vacuum pump. In a known manner, the inlet of the turbomolecular pump is connected to the detector space outlet 16, and the outlet of the turbomolecular pump is connected to the inlet of the pre-vacuum pump. The outlet of the pre-vacuum pump may be open to the atmosphere.

[0037] The detector space inlet 15 is provided with a first flow restriction D1 which provides pressure transduction at the detector space inlet 15. The detector space inlet 15 is connected to the test chamber outlet 26 by a first gas line 28.

[0038] The leak detection system 10 further includes a test chamber 20. The test chamber 20 includes a test chamber space 21, a first test chamber inlet 22 opening into the test chamber space 21, a second test chamber inlet 24 opening into the test chamber space 21, and a test chamber outlet 26 also opening into the test chamber space 21. The test chamber outlet 26 is connected by a first gas line 28 to the first flow restrictor D1 and the detector space inlet 15 in gas communication.

[0039] In this specification, the section of first gas line 28 connecting test chamber outlet 26 to detector space inlet 15 is referred to as test chamber section 34. In this specification, the section of first gas line 28 connecting detector space inlet 15 to test chamber vacuum pump 27 is referred to as detector section 40.

[0040] A second gas line 30 also connects the test chamber outlet 26 to the vacuum chamber vacuum pump 27. The second gas line 30 extends in parallel with the first gas line 28, thereby forming a bypass for the first gas line 28. The second gas line 30 is connected to the first gas line 28 and the gas inlet of the test chamber vacuum pump 27 at a first connection point 38 so that gas can be conducted therethrough.

[0041] The first gas line 28 includes a selectively closeable first valve V1 in its test chamber section 34 and a selectively closeable second valve V2 in its detector section 40. The first gas line 28 includes a third flow restrictor D3 between the second valve V2 and the first connection point 38, the third flow restrictor D3 having a predetermined conductance S3 or an adjustable conductance S3.

[0042] The second gas line 30 includes a fourth flow restrictor D4 having a predetermined conductance S4 or an adjustable conductance S4 between the test chamber outlet 26 and the first connection point 38. The second gas line 30 includes a selectively closable sixth valve V6 between the fourth flow restrictor D4 and the test chamber outlet 26.

[0043] The test chamber outlet 26 is further connected in gas communication to the test chamber vacuum pump 27 by a third gas line 32. The third gas line 32 is connected in gas communication to the first gas line 28 and the second gas line 30 at a second connection point 42 at the test chamber outlet 26. The third gas line 32 straddles the first gas line 28 and the second gas line 30 between the first connection point 38 and the second connection point 42, and includes a selectively closeable fifth valve V5. The first, second, and third gas lines 28, 30, and 32 are connected in gas communication to each other and to the gas inlet of the test chamber vacuum pump 27 at the first connection point 38.

[0044] The first gas line 30 is connected to a first pressure gauge PG1 in the test chamber section 34 between the first flow restriction D1 and the first valve V1. The detector section 40 is connected to a second pressure gauge PG2 between the third flow restriction D3 and the first connection point 38.

[0045] The test chamber 20 is gas-communicatingly connected to a third pressure gauge PG3 in the form of a total pressure sensor that measures the pressure in the test chamber 20. The first test chamber inlet 22 is provided with a second flow restrictor D2 of predetermined or adjustable conductance S2 for supplying carrier gas, and a selectively closable third valve V3. The second test chamber inlet 24 is provided with a selectively closable fourth valve V4 used for flushing and / or venting the test chamber volume 21.

[0046] The section of the first gas line 28 that connects the first connection point 38 to the gas inlet 15 and the first flow restrictor D1 is referred to as the detector section 40. The detector section 40 includes the second valve V2 and the third flow restrictor D3, and is connected to the second pressure gauge PG2. The detector section 40 is connected at the first connection point 38 to the second gas line 30, the third gas line 32, and the gas inlet of the test chamber vacuum pump 27 so that gas can be conducted therethrough.

[0047] The detector space 14 of the gas detector 12 is evacuated in a known manner by a detector vacuum pump 18 to a suitable high vacuum pressure within the detector space 14. To test the leak-tightness of a test object (not shown), the test object is introduced into a test chamber 20 containing a fluid test medium. The test medium may be a test gas or a test liquid that detects leaks in its vapor phase. Valve V5 is then opened, and the test chamber 20 is evacuated by a test chamber vacuum pump 27. Once the appropriate pressure has been reached within the test chamber 20, the fifth valve V5 is closed.

[0048] By opening the sixth valve V6 and the third valve V3, the test chamber vacuum pump 27 draws carrier gas into the test chamber volume 21 via the second flow restriction D2 and supplies it from the test chamber outlet 26 through the fourth flow restriction D4 along the second gas line 30 as the first divided flow to the test chamber vacuum pump 27. By opening the first valve V1 and the second valve V2, a second divided flow of carrier gas conveyed from the test chamber 20 is supplied along the first gas line 28 past the detector inlet 15 and through the detector section 40 to the test chamber vacuum pump 27 via the third flow restriction D3. By appropriately adjusting the conductance of the flow restrictions D3 and D4, a flow division is achieved in which the first divided flow is significantly greater than the second divided flow along the detector inlet 15.

[0049] If there is leakage gas from the test specimen, the carrier gas from the second branch, containing the leakage gas, flows through the first flow restrictor D1 into the detector space 14 for analysis therein. For this purpose, the first gas line 28 is connected to the gas detector 12 by a short line section 46 of the detector space gas inlet 15 at a third connection point 44 that joins the test chamber section 34 to the detector section 40. Alternatively, in other exemplary embodiments not shown, the first gas line 28 can be connected to a different type of gas detector 12 at the third connection point 44.

[0050] By adjusting the conductance of the second flow restrictor D2, the carrier gas flow rate is adjusted to the gas volume in the test chamber space 21 or test chamber 20. If the carrier gas flow rate changes while the suction rate of the test chamber vacuum pump 27 and / or the net suction rate acting through the restrictors D3 and D4 remains the same, the equilibrium pressure in the test chamber 20 will change. To ensure that changes in the test chamber pressure do not also affect the pressure inside the detector space 14, the suction rate of the test chamber vacuum pump 27 is adjusted to the desired inlet pressure of the detector space inlet 15 by adjusting the conductance of the fourth restrictor D4. The partial flow ratio of the two branches supplied to the test chamber vacuum pump 27 is then adjusted by the third flow restrictor D3 so that the predetermined second branch is directed along the detector space inlet 15 and the main part of the carrier gas flow is directed directly to the test chamber vacuum pump 27 as the first branch.

[0051] The detector space 14 continues to be evacuated by the detector vacuum pump 18 .

[0052] (Measurement procedure)

[0053] [Table 1]

[0054] During measurement, carrier gas flows into the test chamber 20 through valve V3. The force of the carrier gas flow is determined by restriction D2. Downstream after the test chamber 20, the carrier gas flow splits into two parts at the second connection point 42. The larger part is guided through the second gas line 30 directly to the test chamber vacuum pump 27 via V6 and restriction D4. The other smaller part flows along the first gas line 28 via the first valve V1 and along the detector section 40 via valve V2 and restriction D3, also to the test chamber vacuum pump 27. The flow rate into the detector space 14 through restriction D1 is negligible compared to the carrier gas flow.

[0055] The sum of the suction / conductance of the two flow restrictions D3, D4 of the split flows that meet at first connection point 38 is selected to achieve the desired equilibrium pressure in test chamber 20 for the selected carrier gas flow rate (determined by restriction D2).

[0056] The following applies: P=Q / S (where S=S3+S4) (In the formula, Q is the carrier gas flow rate, S is the conductance of the restriction (corresponding to the suction amount restricted by the restriction), S3 is the conductance of the restriction D3, S4 is the conductance of the restriction D4, and P is the equilibrium pressure in the test chamber.)

[0057] The decision-making process for interpreting each parameter follows this sequence:

[0058] The carrier gas flow rate is specified and selected to replace the net volume of gas in the test chamber 20 as completely as possible in a short period of time.

[0059] In this case, the flow rate of the carrier gas should not be too high so as not to excessively dilute the test gas.

[0060] In applications where the net volume of the test chamber 20 is large, the pressure is reduced to a lower level so that less gas needs to be displaced by the carrier gas. The pressure is not set too low so that a simple and inexpensive pump can be used as the test chamber vacuum pump. The equilibrium pressure is adjusted using the restrictions D3 and D4.

[0061] The conductance ratio of the apertures D3 and D4 is selected to ensure that gas exchange is performed sufficiently quickly at the detector space inlet 15 (path V1 ⇒ V2 ⇒ D3) to the detection system of the gas detector 12 in the first gas line 28.

[0062] 2 differs from the embodiment shown in FIG. 1 in that the types and lengths of the paths of the first and second gas lines 28, 30 are significantly different, and the gas detector 14 is not necessarily a mass spectrometric gas detector. Rather, the gas detector 14 may be any conceivable type of gas detector, in particular an optical gas analyzer based on the principles of optical emission spectroscopy, infrared absorption, etc., or a gas detector with a surface-type sensor along which the second branched flow is guided.

[0063] From the description of the line paths in Figure 2, it is clear that the first gas line 28 forms a shared gas line path with the test chamber section 34 and the detector section 40, and that the shared gas line path connecting the two connection points 42, 38 extends between those two connection points 42, 38 in parallel with the gas line path formed by the second gas line 30.

[0064] The line section 46 of the detector inlet 15 between the detector space 14 and the third connection point 44 is kept short to ensure rapid replacement of the detector gas with the carrier gas flow through the third connection point 44. Specifically, the line section 46 is shorter than the first gas line 28, the second gas line 30, the detector section 40, and the test chamber section 34.

[0065] A further difference between the exemplary embodiment according to Fig. 2 and the exemplary embodiment according to Fig. 1 is that pressure gauges PG1, PG2, and PG3, second test chamber inlet 24 with fourth valve V4, third valve V3, and flow restrictor D1 are not shown in Fig. 2. However, one or more of these components may be provided in the exemplary embodiment shown in Fig. 2. That is, it is also conceivable that valve V1 and / or valve V2, second flow restrictor D2, and / or third gas line path 32 with fifth valve V5 are omitted from the exemplary embodiment of Fig. 2. Depending on the type of application and the type of detector, it is also conceivable that one or more of valves V1, V2, and V6 are omitted.

Claims

1. A carrier gas leak detection system (10) for detecting leaks in a test specimen, Gas detector (12), A test chamber (20) comprising at least a first test chamber inlet (22), a test chamber outlet (26), and a test chamber vacuum pump (27) for evacuating the test chamber outlet (26), A first gas line (28) connects the outlet (26) of the test chamber to the detector space inlet (15) and the test chamber vacuum pump (27) so that gas can be supplied to them, In a carrier gas leak detection system (10) that includes the following, A second flow restriction (D2) sets the flow rate of the carrier gas passing through the first test chamber inlet (22), A second gas line (30) connects the outlet (26) of the test chamber to the test chamber vacuum pump (27) in parallel with the first gas line (28), wherein the first gas line (28) and the second gas line (30) are connected to the test chamber vacuum pump (27) at a first connection point (38) so as to allow gas to flow through the second gas line (30), A third flow restriction (D3) in the detector section (40) between the first connection point (38) of the first gas line (28) and the detector space inlet (15), A fourth flow restriction (D4) in the second gas line (30) between the test chamber outlet (26) and the first connection point (38), A carrier gas leak detection system (10) is provided such that the third flow restriction (D3) and the fourth flow restriction (D4) constitute a flow restriction means, enabling the vacuum of the first flow passing through the first gas line (28) and the second flow passing through the second gas line (30) to be drawn from the test chamber (20) by the test chamber vacuum pump (27).

2. A carrier gas leak detection system (10) according to claim 1, characterized in that the conductance S3 of the third flow restriction (D3) is lower than the conductance S4 of the fourth flow restriction (D4).

3. A carrier gas leak detection system (10) according to claim 1 or 2, wherein the test chamber section (34) of the first gas line (28) between the test chamber outlet (26) and the detector space inlet (15) includes a selectively closable first valve (V1), and the detector section (40) includes a selectively closable second valve (V2) between a first flow restriction (D1) and a third flow restriction (D3).

4. A carrier gas leak detection system (10) according to claim 1, characterized in that a third valve (V3) that can be selectively closed is provided at the inlet (22) of the first test chamber.

5. A carrier gas leak detection system (10) according to claim 1, characterized in that the test chamber (20) comprises at least one second test chamber inlet (24) used for ventilation or flushing of the test chamber (20) by a fourth valve (V4) that can be selectively closed.

6. A carrier gas leak detection system (10) according to claim 1, characterized in that the outlet (26) of the test chamber is connected to the test chamber vacuum pump (27) at the first connection point (38) by a third gas line (32) which is arranged in parallel with the first and second gas lines (28, 30) and is provided with a fifth valve (V5) that can be selectively closed.

7. A carrier gas leak detection system (10) according to claim 1, characterized in that the second gas line (30) includes a selectively closable sixth valve (V6).

8. A carrier gas leak detection system (10) according to claim 1, wherein the gas detector (12) comprises a detector space (14), a detector space inlet (15), a detector space outlet (16), and a detector vacuum pump (18) of the detector space outlet (16), and the detector space inlet (15) comprises a first flow restriction (D1) that performs pressure conversion at the detector space inlet (15).

9. A carrier gas leak detection system (10) according to claim 8, characterized in that the gas detector (12) is a mass spectrometer, particularly a quadrupole mass spectrometer, and / or the detector vacuum pump (18) is a high vacuum pump system including a turbomolecular pump and a pre-vacuum pump.

10. A carrier gas leak detection system (10) according to claim 3, characterized in that a first pressure gauge (PG1) for measuring the pressure of the first gas line (28) is connected between the first valve (V1) and the first flow restriction (D1) of the first gas line (28).

11. A carrier gas leak detection system (10) according to claim 1, characterized in that a second pressure gauge (PG2) for measuring the pressure of the first gas line (28) is connected between the first connection point (38) and the third flow restriction (D3) in the detector section (40).

12. A carrier gas leak detection system (10) according to claim 1, characterized in that the test chamber (20) is connected to a third pressure gauge (PG3) for measuring the pressure in the test chamber (20).

13. A carrier gas leak detection method for detecting leaks in a test specimen using the carrier gas leak detection system (10) described in claim 1, The process of introducing the test specimen into the test chamber (20), The process of evacuating the test chamber (20) with the test chamber vacuum pump (27), The process of supplying a carrier gas to the test chamber (20) containing the test specimen via the second flow restriction (D2), The process of evacuating the second gas line (30) with the test chamber vacuum pump (27), A process of specifying the conductance of the third flow restriction (D3) and the fourth flow restriction (D4) as flow restriction means so that the first flow restriction passing through the first gas line (28) and the second flow restriction passing through the second gas line (30) can be vacuumed from the test chamber (20) by the test chamber vacuum pump (27), The process of analyzing the gas from the second branch using the gas detector, A carrier gas leak detection method characterized by comprising the following:

14. A carrier gas leak detection method according to claim 13, characterized in that the gas detector (12) comprises a detector space (14) and a detector vacuum pump (18) for evacuating the detector space (14) to a vacuum pressure necessary for gas detection.

15. A carrier gas leak detection method according to claim 13 or 14, characterized in that the flow rate of the gas along the first branch is greater than the flow rate of the gas along the second branch.

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