Vacuum leak detection system, gas control unit and gas leak detection method

Abstract

A vacuum leak detection system (10) includes a test chamber unit (12) having a test chamber inlet (20) and a test chamber outlet (22), a gas detection unit (14) having a gas detection inlet (32) and a gas detection outlet (34), and a gas control unit (16) connecting the test chamber inlet (20) and the test chamber outlet (22) to the gas detection inlet (32) and the gas detection outlet (34), which is connected to the test chamber unit (12) and the gas detection unit (14) and has separate gas conducting pathways (48, 54, 56, 60) for selectively connecting the inlets (20, 40) and the outlets (22, 34) of the test chamber unit (12) and the gas detection unit (14), wherein the gas control unit (16) has a third inlet (44) in communication with the atmosphere and the third inlet (44) can be connected to the test chamber inlet (20) by a gas conducting pathway (48) through the gas control unit (16) to supply carrier gas drawn in by the third inlet (44) to the test chamber unit (12).

Description

Technical Field

[0001] This invention relates to a vacuum leak detection system, a gas control unit, and a gas leak detection method. Background Technology

[0002] Classic helium vacuum leak detection devices, such as those from INFICON. An integrated helium gas measurement device, comprising a vacuum control unit and a mass spectrometer, is described. The device includes a vacuum pump for connection to a test chamber or test object via a separate vacuum line. The vacuum control unit, helium mass spectrometer, and vacuum pump are housed within a single unit.

[0003] In another helium vacuum leak detection device, from Inforcom In this system, a sector-field mass spectrometer and a turbomolecular pump with a flanged valve block form an integrated helium detector unit. The testing system includes a test chamber, a pump holder, and a vacuum leak detector. The helium detector unit is connected to the vacuum test chamber and the pump holder via corresponding connecting cables for gas delivery. Summary of the Invention

[0004] One object of the present invention is to provide a vacuum leak detection system for test gas that can flexibly and controllably supply test gas from the test chamber to the gas detector.

[0005] The vacuum leak detection system according to the invention is defined by the technical features in independent claim 1. The gas detection unit according to the invention is defined by the gas control unit in independent claim 2.

[0006] Based on the above, the vacuum leak detection system comprises three components: a test chamber unit with a test chamber inlet and a test chamber outlet; a gas detection unit with a gas detection inlet and a gas detection outlet; and a gas control unit connecting the gas detection unit and the test chamber unit via the inlet and outlet. The gas control unit is connected to both the test chamber unit and the gas detection unit. The gas control unit includes a separate gas conduction path for selectively connecting the test chamber outlet to the gas detection inlet and the gas detection outlet.

[0007] The gas control unit can be connected to the test chamber unit and gas detection unit of the vacuum leak detection system, and has a separate gas conduction path for selectively connecting the inlet and outlet of the test chamber unit. Specifically, the gas control unit is provided with a separate inlet, which is connected to the test chamber inlet via the gas conduction path through the gas control unit to supply carrier gas to the test chamber unit, which is drawn in through this separate inlet of the gas control unit. A vacuum pump in the gas control unit can be used for this purpose. Specifically, the gas control unit is configured to control the carrier gas supply to the test chamber unit. This means that the carrier gas supply can be turned on and / or off and / or the amount of carrier gas can be changed by the gas control unit. For this purpose, for example, a throttle valve with a variable channel and / or an independently controllable valve can be provided.

[0008] A variation of the invention may involve designing the test chamber unit, the gas detection unit, and the gas control unit as independent modules suitable for detachable connection to each other. These three modules can be directly coupled without requiring separate vacuum lines for connection. In this way, the three modules can form a common vacuum leak detection unit, for example, also housed in a common enclosure. The test chamber unit, the gas control unit, and / or the gas detection unit can be selectively replaced with other modules to adapt the vacuum leak detection system to individual test conditions. Attached Figure Description

[0009] The attached figure is a schematic block diagram of a vacuum leak detection system according to an embodiment of the present invention. Detailed Implementation

[0010] An embodiment of the present invention will now be described in detail with reference to the accompanying drawings. These drawings illustrate the embodiment in the form of schematic block diagrams.

[0011] The accompanying figure shows a vacuum leak detection system 10 having a test chamber unit 12, a gas detection unit 14, and a gas control unit 16.

[0012] The test chamber unit 12 includes a vacuum test chamber 18, which can be a rigid test chamber or a flexible test chamber (e.g., in the form of a membrane chamber). The test chamber unit 12 has a test chamber inlet 20 and a test chamber outlet 22, both of which are connected to the test chamber 18 for air supply.

[0013] The gas detection unit 14 includes a gas detector 24, which in this embodiment is a quadrupole mass spectrometer 24, which exhausts gas to the atmosphere through a two-stage vacuum pump 26. The gas detector 24 is connected to the gas detection inlet 32 ​​and the gas detection outlet 34 via a gas conduction passage 30 equipped with a throttle valve 28.

[0014] The gas control unit 16 is provided with three air inlets 36, 42, and 44 and three air outlets 38, 40, and 46. The first air inlet 36 is connected to the test chamber outlet 22 via a detachable connector. Correspondingly, the first air outlet 38 is connected to the test chamber inlet 20. Correspondingly, the second air outlet 40 is connected to the gas detection inlet 32, and the second air inlet 42 is connected to the gas detection outlet 34. Both the third air inlet 44 and the third air outlet 46 are open to the atmosphere.

[0015] The third inlet 44 is connected to the first outlet 38 via a carrier gas conduction passage 48. The carrier gas conduction passage 48 includes a selectively controllable valve V4 and a throttle valve 50, resulting in a gas flow rate of, for example, 10 sccm. The throttle valve can be used to adapt the flow rate to the test chamber volume 18. Typically, the carrier gas flow rate is between 10 sccm and 100 sccm, depending on the size of the test chamber volume 18. As used herein, selective control means that a corresponding valve can be selectively opened or closed. For this purpose, the gas control unit 16 includes electronics not shown in the figure. A bypass passage 52 bypasses the carrier gas conduction passage 48 and also connects the third inlet 44 to the first outlet 38 via a gas conduction passage, and it includes a selectively controllable valve V5 connected in parallel with valve V4 and throttle valve 50.

[0016] The first air inlet 36 is connected to the second air outlet 40 via a test gas conduction passage 54 including a selectively controllable valve V2. Pressure measuring devices P2 and P3 are connected to the test gas conduction passage 54 so that pressure measuring device P2 measures the pressure downstream of valve V2 in the gas flow direction, and pressure measuring device P3 measures the pressure upstream of valve V2 in the gas flow direction.

[0017] The second inlet 42 is connected to the third outlet 46 via a return test gas conduction path 56, which includes a selectively controllable valve V3 and a vacuum pump 58. Upstream of valve V2 in the gas flow direction, an exhaust gas conduction path 60, including a selectively controllable valve V1, connects the test gas conduction path 54 to the return gas conduction path 56 located between valve V3 and vacuum pump 58. Downstream of valve V1 in the gas flow direction, a pressure measuring device P1, labeled 62, is connected to the exhaust gas conduction path 60.

[0018] The measurement signals from pressure measuring devices P1, P2, and P3 are transmitted to the control electronics of the gas control unit 16 (not shown in the figure). The control electronics control the opening and closing states of valves V1, V2, V3, V4, V5, and V6, as well as the operating state of the vacuum pump 58, based on the measured pressure values ​​and other possible control parameters.

[0019] Initially, valve V1 is open, and at least valves V2 and V3 are closed, while valves V4, V5, and V6 may be closed. Vacuum pump 58 operates and evacuates test chamber 18. Gas from test chamber 18 is drawn through test gas conduction path 54, exhaust gas conduction path 60, and return gas conduction path 56 to the third outlet 46 and discharged into the atmosphere. Simultaneously, vacuum pump 26 evacuates gas detector 24.

[0020] When a suitable pressure threshold is reached at pressure measuring devices P3 and / or P1, valves V2 and V3 open and valve V1 closes. Valve V4 may also open. Valve V5 is initially closed. In this operating state, vacuum pump 58 delivers gas from test chamber 18 from open valve V2 via test gas conduction path 54 to gas detection inlet 32. From gas detection inlet 32, the gas flows through throttle valve 28 to the mass spectrometer of gas detector 24, then through gas detection outlet 34 and second inlet 42, return gas conduction path 56 and open valve V3 to third outlet 46 and is discharged into the atmosphere from there. Suitable carrier gas flows through carrier gas conduction path 48, through open valve V4 and through throttle valve 50 into test chamber 18. The carrier gas originates from the atmosphere surrounding gas control unit 16. Alternatively, it is conceivable to connect the carrier gas source to the third inlet 44.

[0021] After gas leak detection is completed, a corresponding amount of gas can be drawn from the third inlet to flush the test chamber 18, valves, and gas conduction path by bypassing the throttle valve 50 through the bypass gas conduction path 52. For this purpose, a suitable flushing gas source can also be connected to the third inlet 44. Flushing of the test chamber 18 (e.g., to reduce contamination after measuring a large leak rate) is accomplished through a path leading to the pump 58, which passes through pipeline section 52, valve V5, test chamber 18, test gas conduction path 54, and then directly through the open valve V1 and the exhaust gas conduction path 60. During this flushing, the inlet area of ​​the throttle valve 28 used for gas detection is separated by the closed valves V2 and V3. Flushing of the section between pipeline 56 and valves V2 and V3 is achieved through the throttled flushing gas inlet via valve V6. At this stage, valves V2 and V1 are closed. The flushing gas is directed to the pump 58 via valves V6 and V3.

[0022] Gas conduction passages 48, 52, 54, 56, and 60, along with corresponding valves V1-V6, throttle valves, and pressure measuring devices P1-P3, are housed in a shared integral valve block within the gas control unit 16. This block is a solid component. The pressure measuring devices and vacuum pump 58 can be connected to suitable connectors on the valve block. Valves V1-V6 can be disposed externally on the valve block in a known manner and can be connected to corresponding connectors on the respective gas conduction passages.

[0023] Compared to conventional vacuum leak detection systems, the decisive advantage of this invention is that during gas leak detection and for subsequent flushing of the gas conduction path and test chamber, the gas conduction for purging the test chamber can be controlled by a single component, namely the gas control unit 16, without requiring separate hoses to connect the test chamber and / or gas detector to separate components. The carrier gas supply and flushing gas supply are also not guided into the test chamber 18 via separate hoses, but directly into the gas control unit 16. The test chamber 18 has only two ports. No separate ports are needed to supply the carrier gas and / or flushing gas. Correspondingly, the gas detection unit 14 also only requires two ports 32 and 34, and an outlet for purging the mass spectrometer 24, without the need for separate ports for pumps, valves, pressure measuring devices, etc.

Claims

1. A gas control unit (16) for a vacuum leak detection system (10), characterized in that, The vacuum leak detection system (10) includes a test chamber unit (12) having a test chamber inlet (20) and a test chamber outlet (22); and a gas detection unit (14) having a gas detection inlet (32) and a gas detection outlet (34). The gas control unit (16) is configured to connect the test chamber inlet (20) and the test chamber outlet (22) to the gas detection inlet (32) and the gas detection outlet (34). For this purpose, the gas control unit (16) can be connected to the test chamber unit (12) and the gas detection unit (14), and the gas control unit (16) has separate gas conduction paths (48, 54, 56) for selectively connecting the inlets (20, 32) and outlets (22, 34) of the test chamber unit (12) and the gas detection unit (14). Furthermore, the gas control unit (16) has a third air inlet (44) which is in communication with the atmosphere and can be connected to the test chamber inlet (20) through a first gas conduction passage (48) through the gas control unit (16) so as to supply carrier gas to the test chamber unit (12), the carrier gas being drawn in through the third air inlet (44).

2. The gas control unit (16) according to claim 1, characterized in that, The vacuum leak detection system (10) consists of the test chamber unit (12), the gas detection unit (14) and the gas control unit (16) as separate modules suitable for detachable connection to each other.

3. The gas control unit (16) according to claim 1, characterized in that, The gas control unit (16) includes a first air inlet (36) that can be connected to the test chamber outlet (22), a first air outlet (38) that can be connected to the test chamber inlet (20), a second air outlet (40) that can be connected to the gas detection inlet (32), and a second air inlet (42) that can be connected to the gas detection outlet (34). The first air inlet (36) is connected to the second air outlet (40) via a second gas conduction passage (54) extending through the gas control unit (16).

4. The gas control unit (16) according to claim 3, characterized in that, The first air outlet (38) and the second air inlet (42) are not connected via the gas conduction passages (48, 54, 56) extending through the gas control unit (16).

5. The gas control unit (16) according to claim 3, characterized in that, The gas control unit (16) has a third outlet (46) open to the atmosphere, the third inlet (44) is connected to the first outlet (38) via a first gas conduction passage (48) extending through the gas control unit (16), and the third outlet (46) is connected to the second inlet (42) via a third gas conduction passage (56) extending through the gas control unit (16).

6. The gas control unit (16) according to claim 5, characterized in that, The third gas conduction passage (56) connecting the second inlet (42) and the third outlet (46) includes an independently controllable valve (V3) and a vacuum pump (58), and is connected to the second gas conduction passage (54) via a gas guide connection branch (60) that also includes an independently controllable valve (V1), the second gas conduction passage (54) connecting the first inlet (36) and the second outlet (40).

7. The gas control unit (16) according to claim 3, characterized in that, The second gas conduction passage (54) connecting the first air inlet (36) and the second air outlet (40) includes an independently controllable valve (V2).

8. The gas control unit (16) according to claim 3, characterized in that, The first gas conduction passage (48) connecting the third air inlet (44) and the first air outlet (38) includes an independently controllable valve (V4) and a throttle valve (50) connected in parallel therewith, as well as a bypass branch (52) that bypasses the valve (V4) and the throttle valve (50) and includes an independently controllable valve (V5).

9. The gas control unit (16) according to claim 1, characterized in that, The gas conduction passages (48, 54, 56) are configured in a common valve block.

10. The gas control unit (16) according to claim 1, characterized in that, The test chamber unit (12) includes a vacuum chamber of a test chamber (18) designed as a rigid test chamber or a flexible thin-film chamber.

11. The gas control unit (16) according to claim 1, characterized in that, An auxiliary pump module is provided that can be connected to the gas control unit (16) to increase the pumping capacity of the gas control unit (16).

12. A vacuum leak detection system (10), characterized in that, include: The test chamber unit (12) has a test chamber air inlet (20) and a test chamber air outlet (22). Gas detection unit (14), having a gas detection inlet (32) and a gas detection outlet (34); and The gas control unit (16) according to any one of claims 1-11.

13. The vacuum leak detection system (10) according to claim 12, characterized in that, The gas control unit (16) includes a vacuum pump (58) for venting the test chamber unit (12), the vacuum pump (58) being connected to the test chamber outlet (22).

14. A method for detecting gas leaks using the vacuum leak detection system (10) according to claim 13, characterized in that, The gas control unit (16) includes a first inlet (36) connectable to the test chamber outlet (22), a first outlet (38) connectable to the test chamber inlet (20), a second outlet (40) connectable to the gas detection inlet (32), and a second inlet (42) connectable to the gas detection outlet (34). The first inlet (36) is connected to the second outlet (40) via a second gas conduction passage (54) extending through the gas control unit (16). The gas control unit (16) has a third outlet (46) open to the atmosphere. The third inlet (44) is connected to the first outlet (38) via the first gas conduction passage (48) extending through the gas control unit (16), and the third outlet (46) is connected to the second inlet (42) via the third gas conduction passage (56) extending through the gas control unit (16). The method includes the following steps: The vacuum pump (58) of the gas control unit (16) evacuates the test chamber (18) of the test chamber unit (12) via gas conduction passages (48, 54, 56), which connect the first air inlet (36) and the vacuum pump (58) and the third air outlet (46). Block the gas connection branch (60) connecting the first air inlet (36) and the vacuum pump (58), open the second gas conduction passage (54) connecting the first air inlet (36) and the second air outlet (40), and open the third gas conduction passage (56) connecting the second air inlet (42) and the vacuum pump (58), and simultaneously open the first gas conduction passage (48) connecting the third air inlet (44) and the first air outlet (38) so as to supply carrier gas to the test chamber (18) through the third air inlet (44) and supply the mixture of the carrier gas and possible leaked gas to the gas detection unit (14).

15. The method according to claim 14, characterized in that, It also includes the following steps: The test chamber unit (12) and / or the gas detection unit (14) are flushed with gas drawn from the atmosphere surrounding the control unit (16) via the third air inlet (44).

16. The method according to claim 14 or claim 15, characterized in that, When the test chamber (18) is evacuated using the vacuum pump (58) of the gas control unit (16), the second gas conduction passage (54) connecting the first air inlet (36) and the second air outlet (40) and the third gas conduction passage (56) connecting the second air inlet (42) and the third air outlet (46) are both closed.

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