Carrier gas leakage detection system and carrier gas leakage detection method for performing leakage detection on test sample

Abstract

In a carrier gas leak detection system (10) for leak detection of a test sample, comprising 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) that evacuates the test chamber outlet (26), and a first gas line (28) connecting the test chamber outlet (26) to the detector volume inlet (15) and the test chamber vacuum pump (27) in a gas-conducting manner, wherein a second flow throttle valve (D2) is provided for specifying a carrier gas flow through the first test chamber inlet (22), a second gas line (30) connecting the test chamber outlet (26) to a test chamber vacuum pump (27) parallel to the first gas line (28), the first gas line (28) and the second gas line (30) being connected to the test chamber vacuum pump (27) at a first connection point (38) in a gas-conducting manner, a third flow throttle valve (D3) is in a detector portion (40) of a first gas line (28) between a first connection point (38) and a detector volume inlet (15), a fourth flow throttle valve (D4) is in a second gas line (30) between a test chamber outlet (26) and the first connection point (38), and a third flow throttle valve (D5) is in a second gas line (30) between a test chamber outlet (26) and the second connection point (38). The third flow throttle valve (D3) and the fourth flow throttle valve (D4) thus form a flow distributor such that a first partial flow through the first gas line (28) and a second partial flow through the second gas line (30) can be evacuated from the test chamber (20) using the test chamber vacuum pump (27).

Description

[0001] The present invention relates to a system and method for leak detection of a test sample.

[0002] For overall leak detection using a test gas, the test sample is tested in a test chamber using a test gas vacuum leak detection. For this purpose, the test sample filled with the test gas is placed in the test chamber, and then the test chamber is evacuated. The partial pressure of the test gas is measured in the vacuum system using a test gas detector. The test gas flowing into the test chamber from the test sample through the leak can be actively guided to the test gas detector using a carrier gas. For this purpose, the carrier gas is continuously introduced into the test chamber and evacuated using the vacuum system in order to form an equilibrium operating pressure in the test chamber. With the generation of the carrier gas flow, the test gas escaping from the test sample is transported to the test gas detector. The signal intensity present or measured is a measure of the leak rate of the test sample. Depending on the required detection limit, different detectors are used to detect the test gas. A quadrupole mass spectrometer is used to achieve a very high test gas sensitivity. The quadrupole mass spectrometer has both very high sensitivity and high selectivity.

[0003] In principle, the carrier gas method can also be used with other types of detectors that do not necessarily have to operate in a vacuum or high vacuum, such as an optical detector or a surface sensor.

[0004] The maximum sensitivity can be achieved at an optimum total pressure of 1E-4 mbar in the ion source. A lower operating pressure in the detection volume results in lower sensitivity because there are fewer molecules or atoms to be detected, while a higher operating pressure results in a decrease in sensitivity because the space charge effect causes charge carrier losses. If the density of charged particles in the ion source space is too high, the charge carriers will repel each other too strongly.

[0005] For a specific inlet pressure, this optimum operating pressure can be achieved with a fixed suction capacity in the detection volume of the quadrupole mass spectrometer and a fixed conductivity of the pressure sensor inlet (e.g., a capillary). Deviating from this optimum inlet pressure usually has a secondary effect on the total pressure in the ion source.

[0006] For example, halving the inlet pressure results in the total pressure in the high vacuum being reduced to one quarter of the original value. The sensitivity of the system varies with the decrease in the ion source pressure, i.e., a change in the pressure at the inlet of the mass spectrometer disproportionately reduces the sensitivity of the system.

[0007] In the carrier gas method, the carrier gas flow rate should be adapted to the amount of gas present in the test chamber. The goal here is to exchange the gas volume in the chamber approximately two to three times (2-3 tau) in the shortest possible time in order to achieve a converged value of the leak signal.

[0008] In principle, the pressure in the test chamber can be reduced to reduce the amount of gas to be exchanged. However, this means that additional time is required to evacuate the chamber and it results in an increased cost of the pumping system.

[0009] Therefore, for a larger test chamber (larger net chamber volume), the carrier gas flow rate must be increased, and for a smaller net volume, the carrier gas flow rate must be reduced.

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

[0011] Preferably, the operating pressure at the gas detector (e.g., the operating pressure in the detector volume of a mass spectrometry gas detector, especially in the case of a quadrupole mass spectrometer) is adapted to the changing operating pressure in the test chamber. This also applies to other types of detectors. The operating pressure in the test chamber depends on the amount of carrier gas introduced into the test chamber and the pumping capacity of the pump used to evacuate the test chamber. This pump is hereinafter referred to as the test chamber vacuum pump. Adjusting the operating pressure in the detector volume or at the detector by the pumping capacity of the vacuum pump requires a great deal of technical effort and is therefore not very practical. In the case of a vacuum detector, the vacuum pump for evacuating the detector volume is hereinafter referred to as the detector vacuum pump.

[0012] In this context, an object of the present invention is to provide a system and method for leak detection of a test sample by carrier gas leak detection, wherein the flow rate of the carrier gas at the gas detector and the pressure in the test chamber can be adjusted with little technical effort.

[0013] The leak detection system according to the present invention is defined by the features of claim 1. The 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 includes a test chamber volume, at least one first test chamber inlet and a test chamber outlet leading into the test chamber volume, wherein a test chamber vacuum pump for evacuating the test chamber volume is connected to the test chamber outlet. The test chamber outlet is connected in a gas-conducting manner to the gas detector and the test chamber vacuum pump via a first gas line so as to supply the gas to be analyzed from the test chamber to the detector.

[0015] The gas detector may include a detector volume inlet having a first flow throttle for pressure conversion at the detector volume inlet. For example, the first flow throttle may be a suitable cross-sectional configuration of the detector volume inlet. Depending on the type of detector, the first flow throttle is not absolutely necessary. A second flow throttle is provided to supply the carrier gas into the test chamber volume at the test chamber inlet. The second flow throttle may include an adjustable conductivity to change the carrier gas flow rate.

[0016] The second gas pipeline connecting the test chamber outlet to the gas detector parallel to the first gas pipeline is connected in a gas-conducting manner to the test chamber vacuum pump and the first gas pipeline at the first connection point. A third flow throttle valve is provided in the detector section of the first gas pipeline between the first connection point and the gas detector. A fourth flow throttle valve is provided in the second gas pipeline between the test chamber outlet and the first connection point. Thus, the third flow throttle valve and the fourth flow throttle valve, together with the first and second gas pipelines, form a flow distributor, enabling the test chamber vacuum pump to evacuate a first partial flow through the second gas pipeline and a second partial flow through the first gas pipeline from the test chamber.

[0017] The third flow throttle valve is provided in the first gas pipeline between the first flow throttle valve and the test chamber vacuum pump for regulating the pressure in the first gas pipeline. The third flow throttle valve can have an adjustable conductivity. With the third flow throttle valve, the pressure at the gas detector can be preset or selectively adjusted manually or automatically by a pressure control device. The second flow throttle valve can be used to specify or change the carrier gas flow supplied to the test chamber.

[0018] The fourth flow throttle valve is provided in the second gas pipeline between the test chamber outlet and the test chamber vacuum pump. With the fourth flow throttle valve, the suction capacity of the test chamber vacuum pump to suck the carrier gas into the test chamber volume can be specified or adjusted. The test chamber vacuum pump is connected at the first connection point to the first gas pipeline and the second gas pipeline between the third flow throttle valve and the fourth flow throttle valve, such that the main gas flow of the carrier gas passes through the second flow throttle valve, through the test chamber volume via the test chamber inlet, and enters the test chamber vacuum pump from the test chamber outlet via the fourth flow throttle valve. The suction capacity of the test chamber defined by the fourth flow throttle valve together with the third flow throttle valve defines the pressure in the test chamber for a given carrier gas flow.

[0019] The fourth flow throttle valve can also have an adjustable conductivity to change the carrier gas flow and / or the pressure in the test chamber and / or to selectively adjust it manually or automatically, for example, by a pressure control device.

[0020] The first, second, third, and / or fourth flow throttle valves each define the gas conductivity of the corresponding pipeline section and can be specified, for example, by the aperture, capillary, or the conductivity, cross-section, or diameter of the corresponding part of the gas pipeline.

[0021] According to the present invention, with the aid of the third and fourth flow restrictors, the air flow sucked by the test chamber vacuum pump from the test chamber can be separated. Thus, the third and fourth flow restrictors form a flow distributor. A part of the flow rate (hereinafter referred to as the first partial flow rate) directly flows along the first gas pipeline to the test chamber vacuum pump, while another part of the flow rate (hereinafter referred to as the second partial flow rate) flows along the first gas pipeline through the gas detector to the test chamber vacuum pump. The carrier gas in the second partial flow rate (which contains the test gas when a leak occurs in the test sample) is supplied to the detector and analyzed there. For a vacuum or high-vacuum detector with an evacuated detector volume (such as a mass spectrometer), the detector volume is usually continuously evacuated by the detector vacuum pump at the same time.

[0022] The present invention uses an adjustable carrier gas flow rate to detect leaks in a test sample in a test chamber, continuously transports the leak gas or test gas from the test chamber to the detector, and at the same time can selectively adjust the pressure ratio and gas volume required in the detector and the test chamber.

[0023] Accordingly, the carrier gas leak detection method for test sample leak detection according to the present invention is characterized by the following steps:

[0024] · Introduce the test sample into the test chamber,

[0025] · Evacuate the test chamber with the test chamber vacuum pump,

[0026] · Supply the carrier gas to the test chamber containing the test sample through the second flow restrictor,

[0027] · Evacuate the first gas pipeline and the second gas pipeline with the test chamber vacuum pump,

[0028] · Specify or adjust the conductivities of the third flow restrictor and the fourth flow restrictor as the flow distributor so that the first partial flow rate passing through the second gas pipeline and the second partial flow rate passing through the first gas pipeline can be evacuated from the test chamber using the test chamber vacuum pump, and

[0029] · Analyze the gas from the second partial flow rate with a gas detector.

[0030] Preferably, the gas flow rate along the first partial flow rate is greater than the gas flow rate along the second partial flow rate, especially significantly greater than the gas flow rate along the second partial flow rate. The gas flow along the first partial flow rate and the second partial flow rate is specified by the third flow restrictor and the fourth flow restrictor, and this gas flow can be adjusted in the case of a flow restrictor with variable conductivity. The conductivity S3 of the third flow restrictor is preferably lower and especially significantly lower than the conductivity S4 of the fourth flow restrictor. Preferably, the conductivities S3 and S4 can be set, for example, manually or by means of an electronic control device.

[0031] Advantageously, a first valve that can be selectively closed is provided in the test chamber section of the first gas line between the test chamber outlet and the inlet of the gas detector or detector volume, and the detector section includes a second valve that can be selectively closed between the first flow throttle valve and the third flow throttle valve. With the first valve and the second valve, the pressure conditions can be kept constant when evacuating the test chamber using the test chamber vacuum pump. If both the first valve and the second valve are closed, the test chamber can be evacuated through the direct connection between the test chamber vacuum pump and the test chamber without changing the pressure at the detector volume inlet through the evacuation process of the test chamber.

[0032] The test chamber inlet can be provided with a third valve that can be selectively closed.

[0033] The test chamber can have at least one second test chamber inlet for ventilating or flushing the test chamber or test chamber volume, wherein the second test chamber inlet includes a fourth valve that can be selectively closed and is only opened for ventilation or flushing.

[0034] Specifically, the test chamber outlet can be directly connected to the test chamber vacuum pump through a third gas line. The third gas line preferably bridges the second gas line with the fourth flow throttle valve and a sixth valve that may be provided upstream of the fourth flow throttle valve. The third gas line can be provided with a fifth valve that can be selectively closed. When the fifth valve is opened, the test chamber is directly evacuated through the third gas line, for example, after introducing a test sample into the test chamber to reach the desired test chamber vacuum pressure. This test chamber vacuum pressure is advantageously in the range of a few millibars, for example, between 0.1 and 10 millibars. Then the fifth valve is closed and the sixth valve is opened so that when the third valve is opened, a continuous flow of carrier gas is transported through the test chamber volume to the second gas line by means of the test chamber vacuum pump. The sixth valve can also be pre-opened, for example, if the test chamber is evacuated through the third gas line, or the sixth valve may not be present.

[0035] The second gas line with the fourth flow throttle valve and the sixth valve is parallel to the third gas line with the fifth valve. If the first valve, the second valve, the third valve, and the fourth valve are closed, the test chamber can be directly evacuated through the third gas line using the test chamber vacuum pump when the fifth valve is opened. Once the desired test chamber pressure is reached, the fifth valve is closed and the third valve is opened. As a result, the carrier gas is drawn into the test chamber volume through the first test chamber inlet and supplied to the test chamber vacuum pump along the second gas line through the opened sixth valve and the fourth flow throttle valve. At the same time, the gas detector can be evacuated using the gas detector vacuum pump.

[0036] To initiate the leak measurement, open the first valve and the second valve so that a partial flow rate of the carrier gas (hereinafter referred to as the second partial flow rate) is supplied along the first gas line through the gas detector and along the detector section of the test chamber vacuum pump. During this process, the third flow throttle valve and the fourth flow throttle valve determine the ratio of the flow rate distribution. The first partial flow rate flows through the second gas line to the test chamber vacuum pump. The carrier gas, together with the leak gas that may come from the test sample, arrives at or enters the gas detector from the second partial flow rate, which is guided along the first gas line through the gas detector and can be detected there.

[0037] The gas detector can be a vacuum gas detector or a mass spectrometry gas detector, which has a detector volume, and a detector volume inlet and a detector volume outlet lead into the detector volume. The detector vacuum pump is connected to the detector volume outlet in a gas-conducting manner so as to evacuate the detector volume to the required vacuum pressure. Alternatively, the gas detector can be another type of detector, such as an optical detector, a radiation or radiation absorption detector, or a surface sensor, through which the carrier gas flows. In the case of a mass spectrometry gas detector, it can be a quadrupole mass spectrometer. Any type of detector generally requires a vacuum for gas detection, such as a mass spectrometry gas detector, which is hereinafter referred to as a vacuum gas detector. To generate the vacuum required for the vacuum gas detector, a detector vacuum pump different from the test chamber vacuum pump can be provided. The detector vacuum pump can be a high vacuum pump system, which has a high vacuum pump, such as a high vacuum pump in the form of a turbomolecular pump, for evacuating the detector volume, and the high vacuum pump system also has a roughing pump for evacuating the high vacuum pump.

[0038] The first pressure gauge can be connected to the test chamber section of the first gas line between the first valve and the first flow throttle valve to measure the pressure in this test chamber section. The second pressure gauge can be connected to the detector section of the first gas line between the first connection point and the third flow throttle valve to measure the pressure in this detector section. According to the measured pressure, the flow throttle valve D3, the flow throttle valve D4, and / or the valves V1, V2, V6 can be controlled.

[0039] The test chamber is preferably connected to a third pressure gauge for measuring the pressure inside the test chamber, and the second throttle valve D2, the fourth throttle valve D4, the third valve V3, the fourth valve V4, the fifth valve V5, and / or the sixth valve V6 can be controlled according to the measured pressure inside the test chamber.

[0040] Hereinafter, two exemplary embodiments of the present invention will be explained in more detail with reference to the accompanying drawings. Each drawing shows a schematic diagram of a carrier gas leak detection system.

[0041] Figure 1The carrier gas leak detection system 10 of the exemplary embodiment shown is a mass spectrometry carrier gas leak detection system, which includes a mass spectrometry gas detector 12. The mass spectrometry gas detector 12 is in the form of a quadrupole mass spectrometer and has a detector volume 14, a detector volume inlet 15 leading to the detector volume 14, and a detector volume outlet 16 leading to the detector volume 14. A detector vacuum pump 18 is connected to the detector volume outlet 16 to evacuate the detector volume 14. The detector vacuum pump 18 consists of a turbomolecular pump and a forevacuum pump. In a known manner, the inlet of the turbomolecular pump is connected to the detector volume outlet 16, and the outlet of the turbomolecular pump is connected to the inlet of the forevacuum pump. The outlet of the forevacuum pump can lead to the atmosphere.

[0042] The detector volume inlet 15 is provided with a first flow throttle valve D1 for pressure conversion at the detector volume inlet 15. The detector volume inlet 15 is connected to the test chamber outlet 26 through a first gas line 28.

[0043] The leak detection system 10 further includes a test chamber 20 having a test chamber volume 21, a first test chamber inlet 22 leading to the test chamber volume 21, a second test chamber inlet 24 leading to the test chamber volume 21, and a test chamber outlet 26 also leading to the test chamber volume 21. The test chamber outlet 26 is connected to the first flow throttle valve D1 and the detector volume inlet 15 in a gas-conducting manner through a first gas line 28.

[0044] The portion of the first gas line 28 for connecting the test chamber outlet 26 to the detector volume inlet 15 is herein referred to as the test chamber portion 34. The portion of the first gas line 28 for connecting the detector volume inlet 15 to the test chamber vacuum pump 27 is herein referred to as the detector portion 40.

[0045] A second gas line 30 also connects the test chamber outlet 26 to the test chamber vacuum pump 27, wherein the second gas line 30 extends in parallel with the first gas line 28, thereby forming a bypass of the first gas line 28. The second gas line 30 is connected to the gas inlet of the first gas line 28 and the test chamber vacuum pump 27 in a gas-conducting manner at a first connection point 38.

[0046] The test chamber portion 34 of the first gas line 28 includes a selectively closable first valve V1, and the detector portion 40 of the first gas line 28 includes a selectively closable second valve V2. Between the second valve V2 and the first connection point 38, the first gas line 28 includes a third flow throttle valve D3 having a predetermined or adjustable conductivity S3.

[0047] Between the test chamber outlet 26 and the first connection point 38, the second gas line 30 includes a fourth flow throttle valve D4 having a predetermined or adjustable conductivity S4, wherein the second gas line 30 has a selectively closable sixth valve V6 between the fourth flow throttle valve D4 and the test chamber outlet 26.

[0048] The test chamber outlet 26 is also connected in a gas-conducting manner to the test chamber vacuum pump 27 via a third gas line 32. The third gas line 32 is connected in a gas-conducting manner 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 bridges 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 closable fifth valve V5. The first gas line 28, the second gas line 30, and the third gas line 32 are interconnected and are connected in a gas-conducting manner to the gas inlet of the test chamber vacuum pump 27 at the first connection point 38.

[0049] Between the first flow throttle valve D1 and the first valve V1, the first gas line 30 is connected to a first pressure gauge PG1 in its test chamber section 34. The detector section 40 is connected to a second pressure gauge PG2 between the third flow throttle valve D3 and the first connection point 38.

[0050] The test chamber 20 is connected in a gas-conducting manner to a third pressure gauge PG3, which is a total pressure sensor for measuring the pressure in the test chamber 20. The first test chamber inlet 22 includes a second flow throttle valve D2 having a predetermined or adjustable conductivity S2 for supplying carrier gas and a selectively closable third valve V3. The second test chamber inlet 24 has a selectively closable fourth valve V4 for flushing and / or venting the test chamber volume 21.

[0051] The portion of the first gas line 28 that connects the first connection point 38 to the gas inlet 15 and the first flow throttle valve D1 is referred to as the detector section 40. The detector section 40 contains a second valve V2 and a third flow throttle valve D3 and is connected to the second pressure gauge PG2. At the first connection point 38, the detector section 40 is connected in a gas-conducting manner to the second gas line 30, the third gas line 32, and the gas inlet of the test chamber vacuum pump 27.

[0052] The detector volume 14 of the gas detector 12 is evacuated in a known manner by a detector vacuum pump 18 such that a suitable high vacuum pressure is present within the detector volume 14. To test the tightness of a test sample (not shown in the figures) which contains a fluid test medium, the sample is introduced into the test chamber 20. The test medium can be a test gas or a test liquid, the vapor phase of which is used for leak detection. Then, the test chamber vacuum pump 27 evacuates the test chamber 20 with the fifth valve V5 open. Once a suitable pressure is reached in the test chamber 20, the fifth valve V5 is closed.

[0053] By opening the sixth valve V6 and the third valve V3, the test chamber vacuum pump 27 sucks in carrier gas through the second flow throttle D2 into the test chamber volume 21 and supplies the carrier gas to the test chamber vacuum pump 27 as a first partial flow through the test chamber outlet 26 along the second gas line 30 via the fourth flow throttle D4. After opening the first valve V1 and the second valve V2, a second partial flow of the carrier gas conveyed through the test chamber 20 is supplied to the test chamber vacuum pump 27 along the first gas line 28 through the detector inlet 15 and via the detector section 40 through the third flow throttle D3. By appropriately adjusting the conductivities of the flow throttles D3, D4, a flow distribution is achieved such that the first partial flow is significantly greater than the second partial flow along the detector inlet 15.

[0054] From the second partial flow, the carrier gas together with possible leak gas enters the detector volume 14 from the test sample through the first flow throttle D1 and is analyzed at the detector volume 14. For this purpose, the first gas line 28 is connected to the gas detector 12 at a third connection point 44 which connects the test chamber section 34 to the detector section 40 through a short line section 46 of the detector volume gas inlet 15. Alternatively, in another exemplary embodiment (not shown in the figures), the first gas line 28 can be connected to a different type of gas detector 12 at the third connection point 44.

[0055] By adjusting the conductivity of the second flow throttle D2, the carrier gas flow is adapted to the gas volume in the test chamber volume 21 or the test chamber 20. If the suction capacity of the test chamber vacuum pump 27 remains constant and / or the suction capacity effectively acting through the throttle valves D3 and D4 remains constant, the changed carrier gas flow causes a change in the equilibrium pressure within the test chamber 20. To prevent the changed test chamber pressure from also changing the pressure within the detector volume 14, by adjusting the conductivity of the fourth throttle valve D4, the suction capacity of the test chamber vacuum pump 27 is adapted to the required inlet pressure at the detector volume inlet 15. Then the third flow throttle D3 is used to adjust the partial flow ratio of these two partial flows supplied to the test chamber vacuum pump 27 such that a defined second partial flow is guided along the detector volume inlet 15 while the major part of the carrier gas flow is directly guided as the first partial flow to the test chamber vacuum pump 27.

[0056] The detector volume 14 is continuously evacuated by the detector vacuum pump 18.

[0057] Measurement step:

[0058]

[0059] (*) The measurement step 3* can also be skipped.

[0060] During the measurement operation, the carrier gas flows into the test chamber 20 through the valve V3. The intensity of the carrier gas flow is defined by the throttle valve D2. Downstream of the test chamber 20, the carrier gas flow is split into two parts at the second connection point 42. The larger part is directly guided through the second gas line 30 via the valve V6 and the throttle valve D4 to the test chamber vacuum pump 27. The second smaller part of the carrier gas flow flows along the first gas line 28 through the first valve V1 and through the valve V2 and the throttle valve D3 along the detector section 40 to the same test chamber vacuum pump 27. Compared with the carrier gas flow, the flow rate entering the detector volume 14 through the throttle valve D1 can be neglected.

[0061] The sum of the suction capacities / conductivities of the two flow throttle valves D3 and D4 (the partial flows of which are combined at the first connection point 38) is selected such that the required equilibrium pressure is achieved in the test chamber 20 at the selected carrier gas flow rate (defined by the throttle valve D2).

[0062] The following formula applies:

[0063] P = Q / S, where S = S3 + S4

[0064] Q: Carrier gas flow rate

[0065] S: Conductivity of the throttle valve (equivalent to the suction capacity, restricted by the throttle valve)

[0066] S3: Conductivity of the throttle valve D3

[0067] S4: Conductivity of the throttle valve D4

[0068] P: Equilibrium pressure in the test chamber.

[0069] The decision chain for parameter interpretation is as follows:

[0070] Specify the carrier gas flow rate. Select the flow rate such that the amount of gas in the net volume of the test chamber 20 is exchanged as completely as possible in a short time.

[0071] In this process, the carrier gas flow rate should not be set too high so as not to over-dilute the test gas.

[0072] For applications with a relatively large net volume of the test chamber 20, the pressure should be reduced to a lower level so that the amount of gas exchanged with the carrier gas is low. The pressure should not be set too low so that a simple and inexpensive pump can also be used as the test chamber vacuum pump. The equilibrium pressure is adjusted by throttle valves D3 and D4.

[0073] The conductivity ratio of throttle valves D3 and D4 should be selected to ensure sufficiently fast gas exchange in the first gas line 28 at the inlet 15 of the detector volume with the detection system of the gas detector 12 (path V1 => V2 => D3).

[0074] Figure 2 The exemplary embodiment shown in Figure 1 differs from the exemplary embodiment shown in Figure 2 mainly in the type and length of the wiring of the first gas line 28 and the second gas line 30, and the gas detector 14 is not necessarily a mass spectrometry gas detector. Instead, the gas detector 14 can be any conceivable type of gas detector, in particular an optical gas analyzer, such as an optical gas analyzer based on radiation analysis or infrared absorption principle, or a gas detector with a surface sensor, and the second partial flow is guided along the surface of the surface sensor. Figure 2 The pipeline wiring diagram in

[0075] clearly shows that the first gas line 28 forms a common gas line path connecting two connection points 42, 38 with the test chamber section 34 and the detector section 40, and this common gas line path extends between these two connection points 42, 38 and is parallel to the gas line path formed by the second gas line 30. Detector inlet 15 The pipeline section 46 between the detector volume 14 and the third connection point 44 should be kept short. In this way, the carrier gas flow through the third connection point 44 can ensure rapid gas exchange at the detector. Specifically, the pipeline 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.

[0076] Figure 2 The exemplary embodiment shown in Figure 1 Another difference between the exemplary embodiment shown in Figure 2 is that the pressure gauges PG1, PG2, PG3, the second test chamber inlet 24 with the fourth valve V4, the third valve V3, and the throttle valve D1 are not shown in Figure 2 However, one or more of these components can be provided in the exemplary embodiment shown in Figure 2 Therefore, it is also conceivable to omit the valve V1, the valve V2, the second throttle valve D2, and / or the third gas line path 32 with the fifth valve V5 in the exemplary embodiment shown in Depending on the type of application and the type of detector, it is also conceivable to omit one or more of the valves V1, V2, V6.

Claims

1. A carrier gas leak detection system (10) for performing leak detection on a test sample, comprising: a gas detector (12); a test chamber (20), the 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), and a first gas line (28), the first gas line (28) connecting the test chamber outlet (26) to a detector volume inlet (15) and the test chamber vacuum pump (27) in a gas-conducting manner, characterized in that a second flow throttle valve (D2), the second flow throttle valve (D2) being used to preset the carrier gas flow rate through the first test chamber inlet (22), a second gas line (30), the second gas line (30) connecting the test chamber outlet (26) to the test chamber vacuum pump (27) parallel to the first gas line (28), the first gas line (28) and the second gas line (30) being connected to the test chamber vacuum pump (27) in a gas-conducting manner at a first connection point (38), a third flow throttle valve (D3) in a detector portion (40) of the first gas line (28), the first gas line (28) being located between the first connection point (38) and the detector volume inlet (15), and a fourth flow throttle valve (D4) in the second gas line (30), the second gas line (30) being located between the test chamber outlet (26) and the first connection point (38), such that the third flow throttle valve (D3) and the fourth flow throttle valve (D4) form a flow distributor, enabling the test chamber vacuum pump (27) to evacuate a first partial flow through the first gas line (28) and a second partial flow through the second gas line (30) from the test chamber (20).

2. The carrier gas leak detection system (10) according to claim 1, characterized in that the conductivity S3 of the third throttle valve (D3) is lower than the conductivity S4 of the fourth throttle valve (D4).

3. The carrier gas leak detection system (10) according to claim 1 or 2, characterized in that a test chamber portion (34) of the first gas line (28) between the test chamber outlet (26) and the detector volume inlet (15) includes a selectively closable first valve (V1), and the detector portion (40) includes a selectively closable second valve (V2) between the first flow throttle valve (D1) and the third flow throttle valve (D3).

4. The carrier gas leak detection system (10) according to any one of the above claims, characterized in that the first test chamber inlet (22) is provided with a selectively closable third valve (V3).

5. The carrier gas leak detection system (10) according to any one of the above claims, characterized in that The test chamber (20) includes at least one second test chamber inlet (24), and the second test chamber inlet (24) is used to ventilate or flush the test chamber (20) by using a selectively closable fourth valve (V4).

6. The carrier gas leak detection system (10) according to any one of the above claims, characterized in that, The test chamber outlet (26) is connected to the test chamber vacuum pump (27) via the third gas pipeline (32) through the first connection point (38). The third gas pipeline (32) is provided with a selectively closable fifth valve (V5) and is arranged in parallel with the first and second gas pipelines (28, 30).

7. The carrier gas leak detection system (10) according to any one of the above claims, characterized in that, The second gas pipeline (30) includes a selectively closable sixth valve (V6).

8. The carrier gas leak detection system (10) according to any one of the above claims, characterized in that, The gas detector (12) includes a detector volume (14), a detector volume inlet (15), a detector volume outlet (16), and a detector vacuum pump (18) at the detector volume outlet (16). A first flow throttle valve (D1) for pressure conversion is provided at the detector volume inlet (15).

9. The carrier gas leak detection system (10) according to the above claims, 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 having a turbomolecular pump and a forevacuum pump.

10. The carrier gas leak detection system (10) according to any one of the above claims, characterized in that, A first pressure gauge (PG1) is connected to the first gas pipeline (28) between the first valve (V1) and the first flow throttle valve (D1) for measuring the pressure in the first gas pipeline (28).

11. The carrier gas leak detection system (10) according to any one of the above claims, characterized in that, A second pressure gauge (PG2) is connected to the detector section (40) between the first connection point (38) and the third flow throttle valve (D3) for measuring the pressure in the first gas pipeline (28).

12. The carrier gas leak detection system (10) according to any one of the above claims, 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 sample by using the carrier gas leak detection system (10) according to any one of the above claims, characterized in that, includes the following steps: · Introduce the test sample into the test chamber (20), · Evacuate the test chamber (20) with the test chamber vacuum pump (27), · Supply carrier gas into the test chamber (20) containing the test sample through the second flow throttle valve (D2), ·Evacuate the second gas line (30) using the test chamber vacuum pump (27). ·Designate the conductance of the third flow throttle valve (D3) and the fourth flow throttle valve (D4) as a flow distributor so that the test chamber vacuum pump (27) can be used to evacuate a first partial flow through the second gas line (28) and a second partial flow through the first gas line (28) from the test chamber (20), and ·Analyze the gas from the second partial flow using a gas detector.

14. The carrier gas leak detection method according to claim 13, characterized in that the gas detector (12) includes a detector volume (14) and a detector vacuum pump (18), and the detector vacuum pump (18) evacuates the detector volume (14) to the vacuum pressure required for gas detection.

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

Images