Sniffer probe with bypass opening for gas leak detector

Abstract

A sniffer probe (10) for a gas leak detector (18) having a vacuum pump (20) for aspirating gas through the sniffer probe according to the sniffer principle and a gas detector (22) for analyzing the aspirated gas stream, the sniffer probe (10) comprises a gas inlet (28) for the aspirated gas stream, a gas outlet (26) connectable to the gas leak detector, and a channel (16) connecting the gas inlet to the gas outlet in gas communication. The sniffer probe comprises a bypass opening (30) connecting a portion of the channel located between the gas inlet (28) and the gas outlet (26) in gas communication with an environment (32) external to the sniffer probe, the bypass opening having an actuatable closure (36) for selectively opening and closing the bypass opening.

Description

Technical Field

[0001] The present invention relates to a sniffer probe for a gas leak detector having a vacuum pump for sucking gas through a sniffer probe based on the sniffing principle and a gas detector for analyzing the sucked gas flow. Such a gas leak detector is also called a sniffer gas leak detector. The vacuum pump is designed to suck gas from the atmosphere through a gas inlet and supply it to the gas detector.

Background Art

[0002] For this purpose, the sniffer probe has a gas inlet for the sucked gas flow and a gas outlet connectable to the gas leak detector, and the gas is supplied to the gas leak detector and the gas detector. Further, the sniffer probe has a channel connecting the gas inlet to the gas outlet in a gas conducting manner. Here, the sniffer probe may be an integral part of the gas leak detector or may be removably connectable to the gas leak detector as a separate element.

[0003] The larger the flow rate of the sniffer gas sucked through the gas inlet, that is, the larger the flow rate, the faster the gas leaked from the leak location of the object to be inspected can be detected, and the larger the distance to the leak location where the leaked gas may be detected, the more gas volume is conveyed to the gas leak detector per unit time. On the other hand, when the gas flow is large, the space where the gas is sucked becomes larger and the volume of the sucked gas is large, so that it becomes more difficult to accurately locate the leak. The larger the area where the analyzed gas is sucked, the larger or more inaccurate the location of the gas leak becomes.

[0004] The accuracy of gas leak location identification can be improved by reducing the sniffing gas flow. However, this also increases the measured concentration of the leaking gas and often causes pressure changes in the leak detection device.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] An object of the present invention is to provide a sniffer probe that enables rapid leak detection even at a greater distance from the gas leak location and improves the accuracy of locating the leak location.

Means for Solving the Problems

[0007] The sniffer probe according to the present invention is defined by the features of independent claims 1 and 2, respectively.

[0008] Accordingly, a first variant of the present invention provides that the sniffer probe comprises a bypass opening which connects a portion of the channel located between the gas inlet and the gas outlet in a gas-conducting manner to the external environment of the sniffer probe, the bypass opening having an operable closure body for selectively opening and closing the bypass opening. When the bypass opening is closed, the flow through the suction opening is maximized, so that a large gas volume is sucked through the gas inlet per unit time. Thereby, the distance between the leak location and the gas inlet can be increased, where the gas escaping from the leak location can still be detected. However, the accuracy of locating the gas leak decreases when the bypass opening is closed and can be improved by opening the bypass opening. As a result, a part of the gas flow supplied to the detector is sucked through the bypass opening, but only a smaller part of the gas flow supplied to the detector is sucked through the gas inlet compared to the case of the closed bypass opening. When the gas inlet is directed towards the leak location, the volume of the leak area from which the potentially leaking gas is sucked is reduced compared to the case of the closed bypass opening, thereby improving the accuracy of leak detection, i.e., in a sense, the spatial resolution.

[0009] The channel connecting the bypass opening and / or the gas inlet to the gas outlet is preferably dimensioned and designed such that when the bypass opening is open, the total gas flow through the bypass opening and the gas inlet is essentially equal to the gas flow through the gas inlet when the bypass opening is closed. That is, the gas flow through the gas outlet when the bypass opening is open is essentially the same as the gas flow when the bypass opening is closed.

[0010] Instead of the first modification example, according to the second modification example, the sniffer probe is provided with a bypass attachment including a bypass gas inlet, a bypass gas outlet connectable to the gas inlet of the sniffer probe, and a bypass channel connecting the bypass gas inlet and the bypass gas outlet in a gas-conducting state, whereby the same technical effect can be obtained. The bypass attachment has a bypass opening that connects a portion of the bypass channel disposed between the bypass gas inlet and the bypass gas outlet to the external environment of the bypass attachment in a gas-conducting state. The bypass attachment can be detachably connected to the sniffer probe such that in the connected state, the bypass gas outlet is connected to the gas inlet of the sniffer probe in a gas-conducting state.

[0011] In the second modification example, the distance between the gas inlet or the bypass gas inlet and the leakage point, where the gas detector can still detect the gas leaked from the leakage point, is maximum when the bypass attachment is not connected to the sniffer probe. The spatial resolution of the detection of the leaked gas, i.e., the accuracy of the positioning of the leakage point, is maximum when the bypass attachment is attached to the sniffer probe such that the bypass gas outlet is connected to the gas inlet of the sniffer probe.

[0012] In the second variant, the bypass opening and / or the bypass channel are dimensioned and designed such that when the bypass attachment is connected to the sniffer probe, the total gas flow through the bypass opening and the bypass gas inlet is essentially equal to the gas flow through the gas inlet of the sniffer probe when the bypass attachment is removed. In other words, this means that the gas flow at the gas outlet of the sniffer probe with the bypass attachment attached and the bypass opening open corresponds approximately to the gas flow when the bypass attachment is removed, and the bypass attachment has only a negligible influence on this gas flow. In both variants of the invention, the term "essentially" is to be understood such that the gas flow at the gas outlet of the sniffer probe changes by at most about 5% or at most about 10% when the bypass opening is opened and / or when the bypass attachment is attached. This can also be achieved, for example, by means of a suitable variable flow throttle in the channel or in the bypass channel. Alternatively, the flow is essentially affected by the gas flow throttling effect of the capillary line (flexible hose 26) between the sensor unit with the handle and the vacuum pump, so that the effect of the additional bypass opening on the total flow can be neglected.

[0013] In both variants of the invention, the portion of the gas flow supplied to the detector that is drawn from the leakage area is maximum when the bypass opening is closed in the first variant and when the bypass attachment is not connected to the sniffer probe in the second variant. In this case, the distance between the gas inlet and the leakage point is the maximum distance at which the detector can still detect the gas flowing out of the leakage point. The user of the sniffer leak detector can selectively increase the spatial resolution of locating the gas leak by opening the bypass opening in the first variant and connecting the bypass attachment to the sniffer probe in the second variant.

[0014] Also in the second variant, the bypass opening can be thought of as having an actuatable closure for selectively opening and closing the bypass opening. In this case, the closure is arranged on the bypass attachment.

[0015] Basically, the closure can be designed as a slider displaceable in the longitudinal direction of the channel or bypass channel along the outer surface of the sniffer probe or bypass attachment. The slider can surround the sniffer probe or bypass attachment in an annular or ring shape.

[0016] Advantageously, the bypass opening is arranged in a plane extending transversely to the main flow direction of the aspirated gas in the channel or in the bypass channel. Thereby, the main flow direction in which the gas is aspirated through the bypass opening is different from the main flow direction in which the gas is aspirated through the gas inlet or the bypass gas inlet. This has the advantage that when the gas inlet or the bypass gas inlet is directed in the direction of the leak, gas is not aspirated through the bypass opening from the area of the leak.

[0017] This effect can be achieved alternatively or additionally by the distance of the bypass opening from the gas inlet or the bypass gas inlet being at least about 0.5 cm or at least about 2 cm. According to one example of the invention, this distance can be in the range from 0.3 cm to 0.7 cm, preferably in the range from 0.4 cm to 0.6 cm, and thus about 0.5 cm. According to another example of the invention, this distance can be in the range from 1.8 cm to 2.2 cm, preferably in the range from 1.9 cm to 2.1 cm, and thus about 2 cm. According to yet another example of the invention, this distance can also be greater than 2 cm.

[0018] Alternatively or in addition thereto, the bypass opening should be connected to the channel or bypass channel via a gas conduction path whose longitudinal central axis forms an angle of at least about 45° with respect to the longitudinal central axis of the channel or bypass channel, preferably within the range of 60° to 120°, particularly preferably within the range of 80° to 100°. And the gas conduction path connecting the bypass opening and the channel or bypass channel is arranged substantially transversely to the channel or bypass channel. This also has the effect that since the gas is not sucked through the gas inlet or bypass gas inlet but through the bypass opening from another area, there is no possibility that the leaked gas is sucked through the bypass opening when the gas inlet or bypass gas inlet is directed towards the leakage point.

[0019] According to one embodiment, the bypass opening is sized such that the gas flow through the bypass opening is at least 5 times the size of the gas flow through the gas inlet in the first variant of the present invention or the gas flow through the gas inlet in the second variant of the present invention.

[0020] The present invention can also be seen in a combination of a sniffer probe of the type described and a gas leak detector of the type described.

Brief Description of the Drawings

[0021]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Mode for Carrying Out the Invention

[0022] Hereinafter, embodiments of the present invention will be described in more detail with reference to the drawings.

[0023] In all embodiments, the sniffer probe 10 of the gas leak detector has a gas inlet 28, a gas outlet 26, and a channel 16 that connects the gas inlet 28 to the gas outlet 26 in a gas-conducting state. The sniffer probe of the present invention may be, for example, an integral part of a gas leak detector to which the sniffer probe is connected to the gas leak detector via a hose. Alternatively, the sniffer probe may be a separate element from the gas leak detector, in which case the sniffer probe can be connected to the gas leak detector in a removable manner.

[0024] The gas leak detector 18 is shown as an example in FIGS. 3 to 5. The gas leak detector 18 has a vacuum pump 20 for sucking gas and a gas detector 22 for analyzing the sucked gas. The gas leak detector 18 is connected in a gas-conducting state to the gas outlet 26 of the sniffer probe 10 via a flexible hose 24.

[0025] The gas conduction channel 16 connects the gas outlet 26 to the gas inlet 28 of the sniffer probe 10. The sniffer probe is an elongated rotationally symmetric element, and the gas inlet 28 and the gas outlet 26 are arranged on opposite end faces and are connected to each other in a gas-conducting manner by the channel 16.

[0026] In the first embodiment according to FIGS. 1 and 2, the sniffer probe 10 is provided with a bypass opening 30. When the bypass opening 30 is not closed as shown in FIG. 2, this bypass opening 30 connects a portion of the channel 16 located between the gas inlet 28 and the gas outlet 26 to the external environment 32 of the sniffer probe in a gas-conducting state. The bypass opening 30 is parallel to the longitudinal central axis of the channel 16 and is arranged in a plane extending parallel to the main flow direction of the gas conveyed through the channel 16. Also, the longitudinal central axis of the gas conduction path 34 connecting the bypass opening 30 and the channel 16 is arranged laterally with respect to the longitudinal central axis of the channel 16. As a result, when the bypass opening 30 is open, the gas is sucked from another region through the bypass opening 30 rather than through the gas inlet 28 of the sniffer probe 10.

[0027] In the first embodiment, the bypass opening 30 can be closed using a slider 36. The slider 36 is displaceable along the longitudinal direction of the sniffer probe 10 and the channel 16 along the outer shell surface of the sniffer probe 10 so as to close the bypass opening 30 as shown in FIG. 1 and open it as shown in FIG. 2. In the first embodiment, the closure 36 is an annular slider that annularly surrounds the sniffer probe on the outside. Alternatively, the closure 36 may be a ring portion, a flat plate, or a flap similar to those shown in FIGS. 3 and 4.

[0028] The second embodiment in FIG. 3 is different from the first embodiment in that the bypass opening 30 is not provided in the sniffer probe 10 but is provided in a bypass attachment 40 that can be connected to the gas inlet 28 of the sniffer probe 10. The bypass attachment 40 has a bypass gas inlet 42 and a bypass gas outlet 44, and a bypass channel 46 that connects the bypass gas inlet 42 to the bypass gas outlet 44 in a gas-conducting state.

[0029] The bypass attachment 40 is detachably connectable to the sniffer probe 10 as a pluggable element, whereby, in the attached state, the bypass gas outlet 44 is connected in gas communication to the gas inlet 28 of the sniffer probe 10.

[0030] In the second embodiment, the conduit portion 34 is connected to the bypass channel 46. Further, the conduit portion 34 of the second embodiment is arranged transversely to the longitudinal direction of the bypass channel 46. This means that the longitudinal central axis of the conduit portion 34 extends transversely to the longitudinal central axis of the bypass channel 46. The bypass opening 30 is arranged in a plane extending parallel to the main flow direction of the sucked gas in the bypass channel 46 and parallel to the longitudinal central axis of the bypass channel 46. Similarly, the bypass gas inlet is arranged in a plane extending transversely to the plane of the bypass opening 30.

[0031] Similar to the second embodiment of FIG. 3, the third embodiments of FIGS. 4 and 5 correspond to a second variant of the invention provided with a bypass attachment 40. The essential difference of the third embodiment with respect to the second embodiment is that, similar to the closure body of the first variant of the invention, the bypass opening 30 can be selectively opened and closed using an additional closure body 36 in the form of a flap.

Claims

1. A sniffer probe (10) for a gas leak detector (18) having a vacuum pump (20) for aspirating gas through the sniffer probe according to the sniffer principle and a gas detector (22) for analyzing the aspirated gas flow, the sniffer probe comprising a gas inlet (28) for the aspirated gas flow, a gas outlet (26) connectable to the gas leak detector, and a channel (16) connecting said gas inlet and said gas outlet in gas communication; The sniffer probe comprises a bypass opening (30) connecting in gas communication a portion of the channel located between the gas inlet (28) and the gas outlet (26) to an environment (32) external to the sniffer probe, the bypass opening having an actuatable closure (36) for selectively opening and closing the bypass opening, whereby, when the bypass opening is opened, a portion of the gas flow supplied to the detector is drawn through the bypass opening.

2. 2. The sniffer probe of claim 1, wherein the closure (36) is a slider displaceable in the longitudinal direction of the channel along an outer surface of the sniffer probe.

3. 3. The sniffer probe of claim 2, wherein the slider surrounds the outside of the sniffer probe in an annular or ring shape.

4. 4. The sniffer probe according to claim 1, wherein the bypass opening (30) and / or the channel (16) are dimensioned such that, when the bypass opening (30) is open, the total flow rate of the gas flow through the bypass opening (30) and the gas inlet (28) is essentially equal to the gas flow through the gas inlet (28) when the bypass opening (30) is closed.

5. A sniffer probe (10) for a gas leak detector (18) having a vacuum pump (20) for aspirating gas through the sniffer probe according to the sniffer principle and a gas detector (22) for analyzing the aspirated gas flow, the sniffer probe comprising a gas inlet (28) for the aspirated gas flow, a gas outlet (26) connectable to the gas leak detector, and a channel (16) connecting said gas inlet and said gas outlet in gas communication; the sniffer probe has a bypass attachment (40) having a bypass gas inlet (42), a bypass gas outlet (44) connectable to the gas inlet of the sniffer probe, and a bypass channel (46) connecting in gas communication between the bypass gas inlet and the bypass gas outlet; The bypass attachment (40) has a bypass opening (30) that connects in gas communication a portion of the bypass channel arranged between the bypass gas inlet and the bypass gas outlet to an external environment (32) of the bypass attachment, and the bypass attachment is removably connectable to the sniffer probe such that, in a connected state, the bypass gas outlet is connected in gas communication to the gas inlet (28) of the sniffer probe, whereby, when the bypass opening is opened, a portion of the gas flow supplied to the detector is drawn through the bypass opening.

6. 6. The sniffer probe of claim 5, wherein the bypass opening (30) and / or the bypass channel (46) are dimensioned such that when the bypass attachment (40) is connected, the total gas flow through the bypass opening (30) and the bypass gas inlet (42) is essentially equal to the gas flow through the gas inlet (28) when the bypass attachment (40) is removed.

7. 6. The sniffer probe according to claim 5, characterized in that the bypass opening (30) is arranged in a plane extending parallel to a main flow direction of the suction gas in the channel (16) or in the bypass channel (46).

8. A sniffer probe according to any one of claims 5 to 7, characterized in that the bypass opening is located at a distance of about 0.5 cm or at least about 2 cm from the gas inlet or the bypass gas inlet.

9. 9. A sniffer probe as claimed in any one of claims 1 to 8, characterized in that the bypass opening is dimensioned such that the gas flow through it is at least about five times the gas flow through the gas inlet.

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