Hand-held test gas applicator and method for administering test gas

Abstract

The invention relates to a hand-held test gas applicator (12) for administering test gas during vacuum leak detection, comprising a test gas outlet (20), a test gas connection (22) for connecting a test gas reservoir (24), an application line (26) which connects the test gas connection (22) to the test gas outlet (20) in a gas-conducting manner and which has a pressure reducer (28), wherein at least one section of the application line (26) having the pressure reducer (28) is bridged by a bypass line (30) having a check valve (32) in order to fill the test gas reservoir (24) via the test gas outlet (20), wherein the check valve (32) blocks a gas flow from the test gas connection (22) to the test gas outlet (20) and allows a gas flow from the test gas outlet (20) to the test gas connection (22).

Description

[0001] Handheld test gas applicator and method for administering test gas

[0002] The invention relates to a hand-held test gas applicator and a method for administering test gas during vacuum leak detection.

[0003] Handheld test gas applicators are used to release test gas into the external environment of a suspected leak in a test object under test. The test object is typically evacuated and the gas extracted from the test object is tested for the presence of test gas. Test gas applicators are often referred to as spray guns because they usually have a housing with a handle and a spray lance protruding from the housing in a distal, i.e. forward, direction. The proximal, i.e. rear, part of the housing typically has a receptacle for a test gas supply, usually in the form of a gas cartridge. With the help of the spray lance, the test gas can be applied specifically to the area of ​​the test object to be tested by directing the distal tip of the spray lance, which forms the test gas outlet, into the area to be tested, where the test gas is sprayed.

[0004] The test gas is usually helium. Other test gases are also conceivable. Once the test gas supply is empty, it must be replaced or refilled. When replacing the test gas supply, the test gas cartridge is removed from the corresponding receptacle of the test gas applicator before a new, filled test gas cartridge is attached to the receptacle. During this time, the actual test gas delivery is interrupted. It is desirable to keep the interruption in the test gas delivery as short as possible.

[0005] Against this background, the object of the invention is to provide an improved hand-held test gas applicator and an improved method for administering test gas.

[0006] The test gas applicator according to the invention comprises a test gas outlet and a test gas connection. A test gas reservoir is connected to the test gas connection, from which the test gas is administered through the test gas outlet. For this purpose, the test gas outlet and the test gas connection are connected to each other in a vacuum-conducting manner by an application line. The test gas reservoir is usually a pressurized container. The application line is provided with a pressure reducer that reduces the gas pressure prevailing in the test gas reservoir to a lower gas pressure, referred to herein as the "application pressure," which prevails within the section of the application line facing the test gas outlet. The invention is to be seen in the fact that at least one section of the application line containing the pressure reducer is bridged by a bypass line having a check valve.The check valve opens when a pressure limit is exceeded when gas flows from the test gas outlet through the bypass line toward the test gas connection. In the opposite flow direction, i.e., from the test gas connection through the bypass line toward the test gas outlet, the check valve closes. This can be designed, for example, as a conventional spring-loaded check valve, e.g., in the form of a ball valve.

[0007] This makes it possible to administer gas from the test gas supply through the application line via the test gas outlet using the hand-held test gas applicator, while the test gas supply can be filled by introducing test gas through the test gas outlet, flowing through the bypass line, overcoming the limit pressure of the check valve and entering the test gas supply through the test gas connection.

[0008] The method according to the invention therefore consists in administering test gas from a test gas supply connected to the test gas connection via the application line through the test gas outlet and then filling the test gas supply by the test gas flowing into the test gas outlet, flowing through the bypass line, opening the check valve and entering the test gas supply.

[0009] The term "test gas supply" refers here to a replaceable gas storage device, such as a gas tank, which can be a handy gas cartridge or a gas canister. Using a conventional, detachable closure, such as a bayonet lock or a screw cap, the test gas supply can be connected to the test gas connection in a gas-tight and secure but detachable manner. The limit pressure of the check valve can be in the range of a few hundred mbar, e.g., in the range of approximately 100 mbar to approximately 500 mbar, preferably approximately 200 mbar to approximately 300 mbar. The limit pressure of the check valve should be sufficiently low that the test gas, after flowing into the test gas outlet to fill the test gas supply, cannot overcome or damage the pressure reducer in the application line, but instead flows through the bypass line with the check valve, opening and overcoming the check valve.

[0010] It is conceivable that the application line has at least one shut-off valve on the side of the pressure reducer facing the test gas outlet to protect the pressure reducer when refilling the gas supply and to stop the gas flow when not in use as a spray gun. Furthermore, the application line can also have a flow restrictor on the side of the pressure reducer facing the test gas outlet, which restricts the gas flow through the application line during the spraying process.

[0011] The application line and / or the bypass line may be provided with an additional check valve, which may be provided, for example, on the side of the pressure reducer facing the test gas outlet, for example in the connection point between the application line and the bypass line.

[0012] A pressure gauge can be connected to the application line, preferably in a section of the application line connecting the pressure reducer to the test gas connection. The pressure gauge can be used to measure the fill level of the test gas supply both when test gas is being administered via the application line and when the test gas supply is being filled via the bypass line.

[0013] To fill the test gas reservoir, a test gas source is connected to the test gas outlet. An adapter can be provided for this purpose, which is pushed onto or attached to the distal end of the lance. A gas-tight connection between the test gas outlet and the test gas source is essential. The pressure within the test gas source should be greater than the pressure prevailing when the test gas reservoir is fully filled. This pressure can be measured, for example, with a pressure gauge.

[0014] In the following, exemplary embodiments of the invention are explained in more detail with reference to the figures. They show:

[0015] Fig. 1 is a schematic view of the test gas applicator,

[0016] Fig. 2 is a block diagram of a first embodiment and

[0017] Fig. 3 is a block diagram of a second embodiment.

[0018] The test gas applicator 12 shown in Fig. 1 has a housing 14 with a downwardly projecting handle 16. An elongated spray lance 18 protrudes from the housing 14 in the distal, i.e., forward direction (on the left in Fig. 1). The test gas outlet 20 is provided at its distal end. The proximal end of the spray lance, opposite the test gas outlet 20, is connected to the housing 14 in a gas-tight manner.

[0019] The proximal end of the housing 14 opposite the spray lance 18 (the right end in Fig. 1, i.e., the rear end) has a test gas connection 22 for a test gas reservoir 24. The test gas reservoir 24 is a small gas tank in the form of a replaceable gas cartridge filled with test gas. The test gas reservoir 24 is firmly and gas-tightly connected to the test gas connection 22 by a detachable connection.

[0020] Figs. 2 and 3 show block diagrams of two exemplary embodiments of the line routing within the housing 14 connecting the test gas connection 22 to the test gas outlet 20 and the spray lance 18, respectively. In both exemplary embodiments, the test gas connection 22 and the test gas outlet 20 are connected to one another in a gas-conducting manner by an application line 26. The application line 26 has a pressure reducer 28. The pressure reducer 28 is designed to reduce the gas pressure on its side facing the test gas connection 22 to a lower pressure on its side facing the test gas outlet 20.In particular, the pressure within the test gas supply 24 and within the application line 26 between the test gas supply 24 and the pressure reducer 28 should be reduced to a pressure within the application line 26 on the side of the pressure reducer 28 facing the test gas outlet 20 that is suitable for delivering the test gas in a targeted manner via the spray lance 18 into the environment of the test object to be examined, i.e., for spraying it. The reduced pressure on the side facing the test gas outlet 20 is preferably only a few hundred millibars above the ambient pressure in the external environment of the spray lance 18.

[0021] It is conceivable that the application line 26 has at least one shut-off valve on the side of the pressure reducer 28 facing the test gas outlet 20, in order to protect the pressure reducer 28 when refilling the gas supply and to stop the gas flow when not in use as a spray gun. Furthermore, the application line 26 also has a flow restrictor 29 on the side of the pressure reducer 28 facing the test gas outlet 20, which restricts the gas flow through the application line 26 during the spraying process.

[0022] A section of the application line 26 containing the pressure reducer 28 is bridged by a bypass line 30 having a check valve 32. In the illustrated embodiments, the check valve 32 is designed as a spring-loaded ball valve. The check valve 32 blocks gas flow in the distal direction, i.e., from the test gas connection 22 to the test gas outlet 20, so that when test gas is administered, the test gas flows through the application line 26 and the pressure reducer 28. The check valve 32 opens when a limit pressure is exceeded during gas flow in the proximal direction, i.e., from the test gas outlet 20 to the test gas connection 22.The limit pressure of the check valve 32 is designed to be so low that the test gas administered via the test gas outlet 20 for filling the test gas supply 24 cannot flow through the pressure reducer 28 in the proximal direction if there is no closed shut-off valve 33 on the path to the pressure reducer.

[0023] The invention thus makes it easy to refill the same test gas supply 24 with which test gas was previously administered via the spray lance 18, without replacing the gas supply 24. Additional connections are neither provided nor required for refilling the test gas supply 24. This also minimizes the space required within the housing 14, because only the additional bypass line 30 with the check valve 32 is required.

[0024] In the embodiment shown in Fig. 3, a pressure measuring device 36 is additionally connected between the pressure reducer 28 and the test gas connection 22 to the application line 26 in order to measure the gas pressure in the application line 26 on the side of the pressure reducer 28 facing the test gas connection 22.

[0025] A pressure relief valve 38 is connected to the connection point 34 of the application line 26 with the bypass line 30 so that components of the test gas applicator 12 are not damaged if a critical pressure limit is exceeded because the gas then escapes to the outside from the pressure relief valve 38.

[0026] Between the connection point 34 and the test gas connection 22, the application line 26 is provided with a gas filter 40 as shown in Fig. 3. The gas conductance of the application line 26 within the spray lance 18 is represented by the throttle 42.

[0027] In Fig. 3, a further gas supply 25 is shown above the gas supply 24 to illustrate that the test gas supply 24 is replaceable and, after being removed from the test gas connection 22, can be replaced with another test gas supply 25, for example with a different test gas. Both test gas supplies 24, 25 can be filled using the method according to the invention via the bypass line 30. The test gas supply, which is firmly connected to the test gas connection 22, is then refilled via the test gas outlet 20. For this purpose, a test gas source must be connected in a gas-tight manner to the test gas outlet 20, such as the connecting line of a test gas tank or a test gas cylinder, wherein a higher gas pressure prevails in the test gas source than in the test gas supply.

Claims

Claims 1. Hand-held test gas applicator (12) for administering test gas during vacuum leak detection, with a test gas outlet (20), a test gas connection (22) for connecting a test gas supply (24), an application line (26) connecting the test gas connection (22) to the test gas outlet (20) in a gas-conducting manner, with a pressure reducer (28), characterized in that at least a section of the application line (26) having the pressure reducer (28) is bridged by a bypass line (30) having a check valve (32) in order to fill the test gas supply (24) via the test gas outlet (20), wherein the check valve (32) blocks a gas flow from the test gas connection (22) to the test gas outlet (20) and allows a gas flow from the test gas outlet (20) to the test gas connection (22).

2. Hand-held test gas applicator (12) according to claim 1, characterized in that the test gas outlet (20) is formed by a distal end of a spray lance (18) which projects in the distal direction from a housing (14) of the test gas applicator (12).

3. Hand-held test gas applicator (12) according to claim 2, characterized in that the housing (14) has the application line (26) with the pressure reducer (28) and the bypass line (30) with the check valve (32).

4. Hand-held test gas applicator (12) according to claim 2 or 3, characterized in that the housing (14) has a receptacle forming the test gas connection (22) for a test gas tank forming the test gas supply (24).

5. Hand-held test gas applicator (12) according to one of the preceding claims, characterized in that the application line (26) and / or the bypass line (30) are provided with a pressure relief valve (38).

6. Hand-held test gas applicator (12) according to claim 5, characterized in that the application line (26) is connected to a pressure sensor (36) in the region between the pressure relief valve (38) and the pressure reducer (28).

7. A method for administering test gas with a hand-held test gas applicator (12) according to one of the preceding claims, comprising the steps: Connecting a test gas supply (24) to the test gas connection (22), Administering test gas by allowing test gas to flow from the test gas supply (24) through the application line (26) and from the test gas outlet (20), Filling the test gas supply (24) by allowing test gas to flow into the test gas outlet (20), through the bypass line (30) and into the test gas supply 8. The method according to claim 7, characterized in that between the step of administering test gas and the step of filling the test gas supply (24), the test gas supply (24) is not exchanged.

9. Method according to claim 7 or 8, characterized in that before the step of filling the test gas supply (24) a test gas source is connected in a gas-tight manner to the test gas outlet (20).

10. Method according to one of claims 7-9, characterized in that when filling the test gas supply (24) the check valve (32) opens at a limit pressure which is not applied to the pressure reducer (28) in the application line (26).

11. Method according to claim 10, characterized in that when filling the test gas supply (24) the application line (26) on the side of the pressure reducer (28) facing the test gas outlet (20) is blocked.

12. The method according to claim 11, characterized in that the application line (26) is blocked by closing a valve (33).

13. Method according to one of claims 7-12, characterized in that the check valve (32) opens during the step of filling the gas supply at a gas pressure in the bypass line (30) in the range of approximately 100 mbar to 500 mbar and closes automatically when this pressure is undershot.

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