Leak detection device

Abstract

A sniffer-type leak detection device and method using the same eliminates the effects of pressure surges. [Solution] A leak detection device (10) having a gas analyzer (16), a vacuum pump (18), a first intake port (12), and a second intake port (20), a first multi-way valve (14) having a first inlet (28) connected to the first intake (12) and at least first and second outlets (34, 38); a first inlet (32) connected to the second intake (20), and a second multi-way valve (22) connected to at least first and second outlets (36, 40); The first outlets (34, 36) of the two multi-way valves (14, 22) are connected to a gas analyzer (16), and the second outlets (38, 40) are connected to a vacuum pump (18).

Description

Technical Field

[0001] The present invention relates to a leak detection device including a gas analyzer, a vacuum pump, a first intake port, and a second intake port, and particularly to a leak detection device for sniffing-type leak detection.

Background Art

[0002] When detecting a gas leak, the gas is sucked in through an intake port by a vacuum pump and supplied to a gas analyzer to analyze the sucked gas. At that time, the test gas flowing through the leakage point is detected. A specific example of gas leak detection is sniffing-type leak detection in which a constant air flow is sucked in through the intake port of a sniffer probe. While analyzing the sucked gas, the sniffer probe is guided over the object to be inspected. As a result, not only can the leak of the object be detected, but the leakage point can also be pinpointed. When the intake port of the sniffer probe is close to the gas leak point, the test gas leaking through the leakage point is sucked in together with the air flow. As much as possible, a large sniffer gas flow is used so that the leaking gas can be sucked in as reliably and completely as possible. The sniffer gas flow is the flow rate of the gas flow sucked in through the intake port of the sniffer probe. Here, the flow rate of the air flow is usually many times larger than the measured leakage gas flow rate of the test gas leaking from the leakage point.

[0003] The concentration of the leakage gas in the gas flow sucked in through the intake port is the ratio of the leakage rate to the sniffer gas flow. Therefore, the concentration of the leakage gas in the gas flow sucked in by the sniffer probe is usually relatively low. As a result, the sniffer gas flow cannot be selected as large as desired.

[0004] In many cases, the atmosphere surrounding the object contains gas components that generate the same or similar measurement signals for the test gas in the gas detector or gas analyzer. Therefore, these gas components are referred to as interfering gases or background gases. They generate interference signals that cannot be easily distinguished from the measurement signals of the actual leakage gas.

[0005] In known methods for suppressing such interference signals, a measurement gas from the test area of ​​the subject being tested and a reference gas from the surrounding atmosphere are alternately drawn in. The reference gas serves as a reference to determine the proportion of the interfering gas in the drawn-in mixture (reference measurement).

[0006] Such solutions are described, for example, in European Patent No. 1342070 (Patent Document 1) and European Patent No. 1819998 (Patent Document 2). The gas is drawn in by a small sensor unit in the form of an infrared absorption sensor mounted on the handle of the sniffer probe. In International Publication No. 2007 / 031386 (Patent Document 3), a mass spectrometer is used as the gas analyzer. The drawn-in gas must be supplied to the analyzer via a sniffer line. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] European Patent No. 1342070 [Patent Document 2] European Patent No. 1819998 [Patent Document 3] International Publication No. 2007 / 031386 [Overview of the project] [Problems that the invention aims to solve]

[0008] In other sniffer leak detection methods, several, typically two, separate sniffer probes are independently connected to the same gas analyzer and operated alternately, so that the signals from one sniffer probe and the signals from the other are evaluated alternately. In such a so-called multiplexer system, leak detection is performed at multiple locations by sequentially switching from line to line using a gas detection system with several sniffer lines.

[0009] When switching between the two intake ports of a leak detection device connected to the same gas analyzer, a pressure surge occurs in the sniffer line, which affects the measurement signal and leads to signal fluctuations. [Means for solving the problem]

[0010] The object of the present invention is to provide an improved leak detection device and a corresponding leak detection method having two different intake ports, each connected to the same gas analyzer.

[0011] The leak detection device of the present invention is defined by the features described in claim 1. That is, two multiway valves are provided, each having a first inlet and at least first and second outlets. The multiway valves may be, for example, 3 / 2-way valves having one inlet and two outlets. The first outlets of each of the two multiway valves are connected to a first intake port of the leak detection device, while the second outlets of each of the two multiway valves are connected to separate vacuum pumps. The two multiway valves simplify the switching and assignment of two intake ports to the gas analyzer. With one multiway valve, gas drawn in through the first intake port is supplied to the gas analyzer, while gas drawn in through the second intake port is drawn in by the vacuum pump without being supplied to the gas analyzer. By simply switching the multiway valves, the gas flow is drawn in through both intake ports, so pressure surges can be avoided or reduced, while at the same time, one gas flow and the other gas flow can be alternately analyzed by the gas analyzer.

[0012] The two intake ports may be located on different sniffer probes, each connected to two multiway valves by separate sniffer lines. Here, the vacuum pump may be a separate auxiliary pump not connected to the gas analyzer. The gas analyzer may be a mass spectrometry type leak detector having a multistage high vacuum pump. The vacuum pumps connected to the two second outlets are preferably open to the atmosphere.

[0013] Alternatively, the two intake ports may be the measuring gas intake and the reference gas intake of the same sniffer probe. Here, the vacuum pump may form a pump stage, for example, a pre-vacuum stage, of a multi-stage high-vacuum pump in a mass spectrometry gas analyzer. In this case, the two first outlets of the multiway valve are connected to the mass spectrometer, and the two second outlets of the multiway valve are connected via another connection line to a connecting branch that connects the vacuum pump to the other pump stages of the high-vacuum pump and the mass spectrometer. Thresholds are provided in the two connection lines to set the required and desired gas flow, respectively. Alternatively, the connection lines themselves may be designed to act as throttles for the gas flow. The two first outlets may also be connected to two second outlets, so that only a portion of the branched flow is supplied to the gas analyzer, while the remainder of the gas flow is carried to the atmosphere via the vacuum pump.

[0014] Two exemplary embodiments of the present invention will be described in further detail below with reference to the drawings. [Brief explanation of the drawing]

[0015] [Figure 1] A first exemplary embodiment is shown. [Figure 2] A second exemplary embodiment is shown. [Modes for carrying out the invention]

[0016] In both leak detection devices 10 shown in the drawings, the first intake port 12 is connected to a mass spectrometry gas analyzer 16 and a vacuum pump 18 via a first multi-way valve 14 in the shape of a 3 / 2-way valve, and the second intake port 20 is also connected to the gas analyzer 16 and the vacuum pump 18 via a second multi-way valve 22 in the shape of a 3 / 2-way valve.

[0017] In the first exemplary embodiment shown in FIG. 1, the two intake ports 12, 20 are provided on a common sniffer probe 24. The first intake port 12 is directed toward a test area where gas leakage of the subject is suspected, and the second intake port 20 forms a reference intake port, thereby allowing gas to be drawn from the atmosphere surrounding the subject.

[0018] The first intake port 12 is connected to the first inlet 28 of the first multi-way valve 14 via the first connection line 26. The second intake port 20 is connected to the first inlet 32 of the second multi-way valve 22 via another connection line 30.

[0019] Furthermore, in both exemplary embodiments, the first outlet 34 of the first multi-way valve 14 is connected to the first outlet 36 of the second multi-way valve 22 and the gas analyzer 16, and the second outlet 38 of the first multi-way valve 14 is connected to the second outlet 40 of the second multi-way valve 22 and the vacuum pump 18 so that gas transportation is performed.

[0020] In the exemplary embodiment shown in FIG. 2, the two intake ports 12, 20 are provided on separate sniffer probes that can be individually guided, and they are connected to the two multi-way valves 14, 22 via separate connection lines.

[0021] In the first exemplary embodiment shown in FIG. 1, the two first outlets 34, 36 are connected to a shared connection line 42, which at a junction point 44 is connected to a connection line 46 that connects to a second gas outlet 38 of the first multi-way valve 14 and a further connection line 48 that connects to a second outlet 40 of the second multi-way valve 22. The common connection line 42 extends beyond the junction point 44 and is connected to a connection branch 50 that connects the vacuum pump 18 to a second vacuum pump 52. The second vacuum pump 52 is connected to a turbo molecular pump 54, and then its inlet is connected to a gas analyzer 16 in the form of a mass spectrometer. Thus, the vacuum pump 18 forms the first pump stage of a three-stage high-vacuum pump of a mass spectrometry leak detector 56 that consists of the vacuum pump 18, the second vacuum pump 52, the turbo molecular pump 54, and the gas analyzer 16 (mass spectrometer). And the second vacuum pump 52 forms the second pump stage, and the turbo molecular pump 54 forms the third pump stage of a multi-stage high-vacuum pump 60.

[0022] Between the two first gas outlets 34, 36 and the junction point 44, a line 64 that is throttled by a throttle 62 branches off from the connection line 42 and connects to the gas analyzer 16. The line 64 diverts a portion of the gas flow flowing through the line 42 and supplies it to the gas analyzer 16, and the remaining gas flow is supplied to the vacuum pump 18 via the junction point 44 and is discharged into the atmosphere by the vacuum pump 18. Here, the connection line 42 includes a second throttle 66 between the junction point 44 and the connection branch 50, which is used to block the gas flow. By blocking the flow, a pressure surge downstream of the throttle, for example caused by a pump, has no disturbing effect in the form of a pressure fluctuation upstream.

[0023] In the second exemplary embodiment, the multi-way, the connection line 42 from the two outlets 38, 40 to the vacuum pump 18 and the connection line 64 from the two outlets 34, 36 to the gas analyzer 16 are separated from each other and thus are not connected in a gas-conducting manner.

[0024] In both exemplary embodiments, the vacuum pump 18 remains operational while gas analysis is performed using the gas analyzer 16, transporting gas from the intake port 12, 20 that is not connected to the gas analyzer 16 via the multiway valves 14, 22. Thus, in the exemplary embodiments and the switching state shown in Figure 2, gas from the first intake port 12 is supplied to the gas analyzer 16 for gas analysis via the first inlet 28 and first outlet 34 of the first multiway valve 14 and the connecting line 64, while simultaneously, gas flowing in from the second intake port 20 is transported via the second multiway valve 22 from its first inlet 32 ​​to its second outlet 40, and from there released into the atmosphere via the connecting line 42 and the pump 18. Thus, while the gas from the first intake port 12 is analyzed by the gas analyzer 16, the gas from the second intake port 20 is discharged into the atmosphere by the pump 18.

[0025] In the exemplary embodiment shown in Figure 1, the first intake port 12 of the same sniffer probe forms the measurement gas intake port, and the second intake port 20 forms the reference gas intake port. Gas from the first intake port 12 is supplied via line 26 to the first inlet 28 of the first multiway valve 14. Simultaneously, the vacuum pump 18 draws in gas through the second intake port 20, which is supplied via line 30 to the inlet 32 ​​of the second multiway valve 22. In the first switching state, the first multiway valve 14 is connected at the first inlet 28 and the first outlet 34, and the gas drawn in through the first intake port 12 is supplied from the first outlet 34 to the connecting line 42. From this gas flow, a portion of the flow branches off via a throttled line 64 and is supplied to a mass spectrometry gas analyzer 16, while the remaining gas flow passes beyond the junction 44 and through the second throttling 66 and the vacuum pump 18 to the outside air. Simultaneously, the second multi-way valve 22 directs the gas drawn in from the second intake port 20 through the inlet 32 ​​to the second outlet 40, from where the gas flows through line 48 and connection point 44 to the shared connection line 42. From there, the gas is transported to the outside air via the vacuum pump 18.

[0026] Next, both multi-way valves 14 and 22 are switched synchronously from the first switching state to the second switching state. In the second switching state, the first multi-way valve 14 directs the gas from the first intake port 12 to the second vacuum pump 18 via the gas outlet 38, and this gas does not enter the analyzer 16. On the other hand, the second multi-way valve 22 directs the gas from the second intake port 20 to the common connection line 42 via the first gas outlet 36, and a portion of the flow from the common connection line 42 is directed to the gas analyzer 16 via the restricted line 64 for analysis.

[0027] By synchronously switching the two multiway valves 14 and 22 simultaneously, only the gas from one of the two intake ports 12 and 20 can be introduced into the gas analyzer 16 for analysis, while the gas from the other intake port is discharged into the atmosphere via the vacuum pump 18. By synchronously switching the two multiway valves 14 and 22 simultaneously, the two intake ports 12 and 20 can be alternately connected to the gas analyzer without significant delay and / or pressure surge during switching. The continuously pumped flow through both lines 26 and 30 maintains a pressure gradient in the lines, and pressure surges at the inlet to the sensing system are avoided during switching.

[0028] A further advantage of the continuous gas flow through the two lines 26 and 30 is that the gas drawn in through the two inlet openings 12 and 20 also reaches the switching valves 14 and 22 simultaneously. The passage time of the gas leading through lines 26 and 30 can be several seconds. If lines not connected to the gas analyzer 16 or leak detector 56 are not continuously evacuated and not pumped, the reaction time will be delayed by several seconds. The present invention also includes the following embodiments. [Aspect 1] A leak detection device (10) having a gas analyzer (16), a vacuum pump (18), a first air intake (12), and a second air intake (20), A first multi-way valve (14) having a first inlet (28) and at least a first outlet (34) and a second outlet (38), the inlet (28) being connected to the first intake port (12), The system comprises a first inlet (32) and a second multi-way valve (22) having at least a first outlet (36) and a second outlet (40), the inlet (32) being connected to the second intake port (20), The two first outlets (34, 36) of the two multiway valves (14, 22) are connected to the gas analyzer (16), and the two second outlets (38, 40) of the two multiway valves (14, 22) are connected to the vacuum pump (18). A leak detection device (10) characterized by the following. [Aspect 2] In the leak detection device (10) according to claim 1, The aforementioned multi-way valves (14, 22) When the inlet (32) of the second multiway valve (22) is connected to its second outlet (40), the inlet (28) of the first multiway valve (14) is connected to its first outlet (34), and the switching of the two multiway valves (14, 22) is configured to occur synchronously and controlled by a valve control device. A leak detection device (10) characterized by the following. [Aspect 3] In the leak detection device (10) according to claim 2, The two intake ports (12, 20) are located on separate sniffer probes. A leak detection device (10) characterized by the following. [Aspect 4] In a leak detection device (10) according to any one embodiment of claims 1 to 3, The gas analyzer (16) is a mass spectrometry type leak detector (56) having a multi-stage high vacuum pump (60). A leak detection device (10) characterized by the following. [Aspect 5] In the leak detection device (10) according to claim 4, The vacuum pump (18) is a separate auxiliary pump that is not connected to the leak detector (56). A leak detection device (10) characterized by the following. [Aspect 6] In the leak detection device (10) according to claim 4, The leak detection device (10) is characterized in that the vacuum pump (18) forms a pump stage of the multi-stage high vacuum pump (60). [Aspect 7] In a leak detection device (10) according to any one embodiment of claims 1 to 6, The two first outlets (34, 36) are connected to the gas analyzer (16) via a common connecting branch (64), and the two second outlets (38, 40) are connected to the vacuum pump (18) via a common connecting line (42). A leak detection device (10) characterized by the following. [Aspect 8] In a leak detection device (10) according to any one embodiment of claims 1 to 7, The leak detection device (10) is characterized in that the two first outlets are connected to the two second outlets and are connected to the gas analyzer (16) via a narrowed line (64) and to a connecting branch that connects the vacuum pump (18) to the high vacuum pump (60) via another narrowed line (42). [Aspect 9] A sniffer-type leak detection method using a leak detection device (10) according to any one embodiment of claims 1 to 8, The steps include starting the vacuum pump (18), The steps include connecting the inlet (28) of the first multiway valve (14) to its first outlet (34) and connecting the inlet (32) of the second multiway valve (22) to its second outlet (40), The steps include: drawing gas through the second intake port (20) using the vacuum pump (18), and analyzing the gas drawn in through the first intake port (12) using the gas analyzer (16); The steps include driving the vacuum pump (18) while synchronously switching the two multi-way valves (14, 22), The step includes drawing gas through the first intake port (12) using the vacuum pump (18) while analyzing the gas drawn in through the second intake port (20) using the gas analyzer (16), A method characterized by the following: [Explanation of symbols]

[0029] 10 Leak detection device 12 First air intake 14. The first multi-directional dialect 28 Entrance 34. Exit 1 38. Second Exit 16 Gas analyzers 18 Vacuum pump 20 Second air intake 22. The second multidirectional dialect 32 Entrance 36. Exit 1 40 Second Exit 24 Sniffer probes 52. Second vacuum pump 56 Turbomolecular pumps 60 Multistage High Vacuum Pump

Claims

1. A leak detection device (10) having a gas analyzer (16), a vacuum pump (18), a first air intake (12), and a second air intake (20), A first multi-way valve (14) having a first inlet (28) and at least a first outlet (34) and a second outlet (38), wherein the inlet (28) is connected to the first intake port (12), The system comprises a first inlet (32) and a second multi-way valve (22) having at least a first outlet (36) and a second outlet (40), the inlet (32) being connected to the second intake port (20), The two first outlets (34, 36) of the two multiway valves (14, 22) are connected to the gas analyzer (16), and the two second outlets (38, 40) of the two multiway valves (14, 22) are connected to the vacuum pump (18). The aforementioned multi-way valves (14, 22) When the inlet (32) of the second multiway valve (22) is connected to its second outlet (40), the inlet (28) of the first multiway valve (14) is connected to its first outlet (34), and the switching of the two multiway valves (14, 22) is configured to occur synchronously and is controlled by a valve control device. A leak detection device (10) characterized by the following.

2. In the leak detection device (10) according to claim 1, The two intake ports (12, 20) are located on separate sniffer probes. A leak detection device (10) characterized by the following.

3. In the leak detection device (10) according to claim 1, The gas analyzer (16) is a mass spectrometry type leak detector (56) having a multi-stage high vacuum pump (60). A leak detection device (10) characterized by the following.

4. In the leak detection device (10) according to claim 3, The leak detection device (10) is characterized in that the vacuum pump (18) is a separate auxiliary pump that is not connected to the leak detector (56).

5. In the leak detection device (10) according to claim 3, The leak detection device (10) is characterized in that the vacuum pump (18) forms a pump stage of the multi-stage high vacuum pump (60).

6. In the leak detection device (10) according to claim 1, The two first outlets (34, 36) are connected to the gas analyzer (16) via a common connecting branch (64), and the two second outlets (38, 40) are connected to the vacuum pump (18) via a common connecting line (42). A leak detection device (10) characterized by the following.

7. In the leak detection device (10) according to claim 1, The vacuum pump (18) is further connected to a second vacuum pump (52), The leak detection device (10) is characterized in that the two first outlets are connected to the two second outlets, and are connected to the gas analyzer (16) via a narrowed line (64), and to a connecting branch (50) that connects the vacuum pump (18) to the second vacuum pump (52) via another narrowed line (42).

8. A sniffer-type leak detection method using a leak detection device (10) according to any one of claims 1 to 7, The steps include starting the vacuum pump (18), The steps include connecting the inlet (28) of the first multi-way valve (14) to its first outlet (34), and connecting the inlet (32) of the second multi-way valve (22) to its second outlet (40), The steps include: drawing gas through the second intake port (20) using the vacuum pump (18), and analyzing the gas drawn in through the first intake port (12) using the gas analyzer (16); The steps include: driving the vacuum pump (18) while synchronously switching the two multi-way valves (14, 22); The step includes drawing gas through the first intake port (12) using the vacuum pump (18) and analyzing the gas drawn in through the second intake port (20) using the gas analyzer (16), A method characterized by the following:

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