Shielded sniffer probe

Abstract

The invention relates to a sniffer probe (10) for inhaling gas when searching for gas leaks, the sniffer probe comprising at least one sniffer tip (11) and provided with an air inlet (16) which is connected to a main sniffer line via a connecting line and which can be connected to a gas leak detector. The sniffer tip (11) is provided with a flexible, elongated shielding element (30) in the region of the air inlet (16), the shielding element (30) extending from the sniffer tip (11) in such a way that the air inlet (16) is shielded from the external environment (38) of the sniffer probe (10) in all directions.

Description

[0001] The present invention relates to a sniffer probe of a gas leak detector for searching for gas leaks.

[0002] When searching for gas leaks, a sniffer probe is moved along the surface of a test object in the area of ​​the suspected gas leak. For this purpose, the sniffer probe has a sniffer tip equipped with an air inlet, through which the gas-air mixture to be analyzed is drawn in. Typically, the main sniffer line connects the rear end of the sniffer probe, opposite the air inlet, to a gas leak detector, where the drawn-in gas is analyzed.

[0003] Automated sniffing leak detection in pipes can be difficult to detect gas leaks at the rear of the pipe. Conventional sniffer probes require increasing the gas flow rate to draw in the leaking gas along with the air from the rear of the pipe. This reduces the sensitivity of gas leak detection. Alternatively, the sniffer probe must be moved around the pipe, which is time-consuming. In refrigerator pipes, it's particularly difficult to increase the gas flow rate to detect a leak as low as 0.5g / year at the rear of the pipe.

[0004] An object of the present invention is to provide a sniffer probe with which leaks can be detected particularly easily in the rear part of the inspected pipeline.

[0005] A sniffer probe for inhaling gas, the sniffer probe having at least one sniffer tip, the sniffer tip being provided with an air inlet, the air inlet being connected to a main sniffer line via a connecting line, the main sniffer line being connectable to a gas leak detector; characterised in that the sniffer tip is provided with a flexible, elongated shielding element in the region of the air inlet, the shielding element extending from the sniffer tip in such a way that the air inlet is shielded in all directions from the external environment of the sniffer probe.

[0006] The present invention therefore provides a sniffer probe having at least one sniffer tip with a gas inlet. Preferably, in the sniffer probe, for example in the sniffer tip, an extended connecting line connects the gas inlet to a main sniffer line that can be connected to or is connected to a gas leak detector.

[0007] According to the invention, the sniffer tip has a flexible, elongated shielding element in the area of ​​the air inlet, which protrudes from the sniffer tip so that the air inlet is shielded from the environment outside the sniffer probe on all sides. All-round shielding means that a distance of a maximum of several millimeters, preferably less than one millimeter, remains between adjacent shielding elements, through which gas flows from the environment to the air inlet and is sucked in by the air inlet.

[0008] Thus, the shielding element can form a test cavity for the test object to be inspected, said test cavity adjoining the air inlet. The sniffer tip and the shielding element protruding therefrom completely enclose the test cavity, except for a small distance, which should preferably be at most approximately one-tenth of the diameter of the air inlet, so that the test cavity is shielded from the environment outside the sniffer probe by the shielding element. The sniffer probe and the shielding element protruding therefrom thus form a wall that acts like a test cavity, which is permeable to gas in the area of ​​the shielding element and reduces gas turbulence, for example in the event of gusty winds.

[0009] The distance between adjacent shielding elements should not be greater than about one-tenth, preferably about one-hundredth, of the inlet diameter. For an inlet diameter of 4 mm, the distance between adjacent shielding elements should therefore be less than 0.4 mm, preferably less than 40 μm. The inlet diameter refers to the maximum distance between opposing edges of the inlet, so the term "diameter" does not necessarily require a circular inlet.

[0010] The sniffer tip can be designed as an arm of the sniffer tip. In particular, the sniffer probe can include a plurality of, for example two, arms, between which the test cavity is formed. The shielding element protrudes from at least one of the arms.

[0011] At least one arm is provided with at least one, and preferably multiple, flexible shielding elements on its side facing the test cavity. The shielding elements preferably protrude at right angles from the arm and define the test cavity, thereby shielding the air inlet from the external environment of the sniffer probe. The shielding elements may be elastic fiber elements and / or brush-like bristles. The shielding elements shield the sniffer tip and the air inlet from the external environment of the sniffer probe, so that when gas is inhaled, the movement of air mainly moves from the outside of the sniffer probe inward into the interior of the test cavity, so that the main sniffer circuit mainly draws gas from the interior of the test cavity. This reduces the influence of air turbulence in the area outside the sniffer probe on the inhalation of gas escaping through the leak.

[0012] The shielding element can be formed as a flexible fiber, wherein a plurality of fibers are arranged so closely side by side that the fibers delimit a wall which shields the test cavity 20 from the external environment of the sniffer probe. Alternatively, the shielding element can also be provided in the form of a flexible wall.

[0013] The shielding element is advantageously arranged in an edge region of the inner side of the respective arm facing the test cavity, and is further preferably arranged in all edge regions of each arm, so that the shielding element completely delimits the test cavity and thus shields the interior of the test cavity and the air inlet from the external environment of the sniffer probe.

[0014] As the sniffer probe moves over an object to be tested, such as a pipe, one or more fiber elements bend toward the test object and surround the portion of the test object located within the test cavity, shielding it from the external environment. This creates a mobile test cavity for the test object that can be moved over the test object. When the test cavity is evacuated through the air inlet of the sniffer probe, gases such as air flow from the environment outside the sniffer probe into the test cavity through the shielding element. This prevents turbulent air flow in the environment outside the sniffer probe from swirling gas within the test cavity that escapes from leaks in the test object in areas shielded by the shielding element.

[0015] Advantageously, each of the two arms is provided with a shielding element, such that the shielding element extends from two mutually opposing sides into the space between the two arms. Advantageously, at least some of the shielding elements extend approximately to the middle of the distance between the arms, so that the test chamber is at least largely shielded from the environment by the shielding elements.

[0016] Each shielding element comprises a first end arranged at the corresponding arm and a second end opposite the first end. The distance between the second ends of mutually opposite shielding elements extending toward each other from different arms should be small and may be less than 1 / 10 of the diameter of the air inlet, preferably less than 1 / 100 of the diameter of the air inlet.

[0017] To prevent a test object located in the test cavity, such as a tube to be sniffed, from bending the shielding element and creating a free space without the shielding element, at least two shielding elements of different lengths can be provided, so that at least the shorter shielding element shields the resulting cavity from the external environment. In general, the edge region of the test cavity should be as largely penetrated by the shielding element as possible, even when a test object is located in the test cavity and partially bends the shielding element.

[0018] For this purpose, shielding elements of different lengths may be arranged in rows, wherein each row may comprise shielding elements of the same length and wherein rows with shielding elements of different lengths are arranged in an alternating manner.

[0019] Preferably, the air inlet should be at least largely and preferably completely surrounded or shielded by the shielding element.

[0020] The sniffer probe can be designed in a fork-shaped manner and formed in the front end region of the respective arm, while the rear ends of the arms, opposite the front ends, are connected to one another.

[0021] The rear ends of the arms preferably terminate in a common base element, which can be designed, for example, as a handle and contains the main sniffer circuitry. The arms can be Y-shaped or U-shaped, with the U-shaped design being advantageous. In the case of a U-shaped arm design, the air inlet is formed on the inner side of the respective arm facing the test cavity and in its front end region. The U-shaped prongs can then be simply pushed over the pipe in such a way that the pipe to be sniffed is contained within the test cavity, allowing the air inlet to sniff one of multiple sides of the test object, such as the pipeline to be tested.

[0022] The inner sides of the arms facing the test chamber are preferably arranged parallel to one another in the front region, so that the shielding elements also extend parallel to one another.

[0023] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0024] In the attached figure:

[0025] Figure 1 is a perspective view of an embodiment;

[0026] Figure 2 yes Figure 1 View in the direction of arrow II.

[0027] The sniffer probe has two arms 12 and 14 forming a U-shape. The rear ends of the two arms 12 and 14 are integrally connected to a central base element 28, which contains a main sniffer line (not shown) connected to a gas leak detector. Front ends 22 and 24 of the two arms 12 and 14, opposite the rear ends, are spaced apart from each other, forming a test chamber 20 for the pipeline being inspected therebetween.

[0028] On opposite sides of the test cavity 20, gas inlets 16, 18 are formed on the inner sides 26 of the two arms 22, 24 adjacent to the test cavity 20. Alternatively, it is conceivable that only one of the two arms 22, 22 is provided with a gas inlet 16 and the other arm 24 does not have a gas inlet 18, or that the only gas inlet 16 is located centrally between the two arms at the base element 28 or in the area of ​​this base element 28. Alternatively, a capillary tube can be used to introduce the gas inlet into the shielded area.

[0029] Each air inlet 16, 18 is formed in the front region of the front end 22, 24 of the respective arm 12, 14. Each air inlet 16, 18 is connected to the main sniffing circuit in an air-conducting manner via a separate connecting line. These separate connecting lines extend in the respective arm 12, 14 and are not shown in the figure.

[0030] The inner sides 26 of the two arms 12 , 14 are arranged parallel to one another in the region of the front ends 22 , 24 , so that the sniffer probe 10 can be oriented relative to the pipeline to be inspected so that the pipeline to be tested is contained in the test chamber 20 .

[0031] From the inner sides 26 of the two arms 12, 14, flexible shielding elements in the form of elastic fibers or bristles protrude in the manner of a brush and project into or close to the test cavity 20. The shielding elements 30 are arranged parallel to one another.

[0032] The shielding element is arranged only in the edge region 36 of the inner side 26 of the two arms 12, 14. The wall region 36 delimits the inner side from the outer side and completely surrounds the gas inlets 16, 18. The shielding element protruding from the inner side 26 in the edge region 36 thus forms a gas-permeable wall that shields the test chamber 20 from the external environment 38 of the sniffer probe 10.

[0033] Each of the two arms 12, 14 is provided with one or more rows 32 of longer shielding elements 30 and / or one or more rows 34 of shorter shielding elements 30. The rows 34 of shielding elements are shorter than the rows 32 of shielding elements. The rows 32 and 34 alternate with each other, such that a row 34 is arranged between two adjacent rows 32, and vice versa. Each of the rows 32 of longer shielding elements 30 extends to the center of the test cavity 20, so that the rows 32 of shielding elements 30 nearly touch each other in the central region of the test cavity 20. Conversely, each of the rows 34 of shorter shielding elements 30 is formed to be only about half the length of the rows 32 of shielding elements 30, so that space for a test object remains in the central region of the test cavity 20 between the opposing rows 34 of shielding elements 30 that extend from the opposing arms 22, 24 and surround or shield the test cavity 20. Thus, a test object introduced into the test chamber 20 causes the rows 32 of longer shielding elements 30 to bend more than the rows 34 of shorter shielding elements 30 .

[0034] As an alternative, it is conceivable to arrange the longer and shorter shielding elements 30 alternately, rather than in rows of equal length. Here, a shorter fiber element 30 can be surrounded by a plurality of longer shielding elements, and vice versa.

[0035] The shielding element 30 shields the air inlet 16 from the external environment of the sniffer probe 10 in such a way that the influence of air turbulence in the area outside the test chamber 20 on the air flow inside the test chamber 20 and in the direction of the air inlet 16 or 18 is reduced.

[0036] In another embodiment, not shown in the figures, only one arm configured as a sniffer tip is provided, which has an air inlet in the area of ​​the sniffer tip. Here, a flexible, elongated shielding element extends into the area of ​​the air inlet. The shielding element can be bristle-like, elongated fibers and / or a flexible wall. Essential to the present invention, the test cavity adjacent to the air inlet is shielded from the external environment of the sniffer probe on all sides by the shielding element, so that a distance of at most 1 / 5 of the diameter of the air inlet, preferably less than 1 / 10 or less than 1 / 100 of this diameter, exists between adjacent shielding elements. The shielding element forms a wall that completely surrounds and / or delimits the test cavity.

Claims

1. A sniffer probe for inhaling gas, the sniffer probe comprising at least one sniffer tip, the sniffer tip being provided with an air inlet, the air inlet being connected to a main sniffer line via a connecting line, the main sniffer line being connectable to a gas leak detector; Its characteristics are: The sniffer tip is provided with a flexible, elongated shielding element in the region of the air inlet, the shielding element extending from the sniffer tip in such a manner that the air inlet is shielded from the environment outside the sniffer probe on all sides; the shielding element forming a flexible, gas-permeable wall of a test cavity for a test object to be inspected, the test cavity being adjacent to the gas inlet, wherein the sniffer probe and the shielding element extending from the sniffer probe all-around surround the test cavity and shield it from an environment external to the sniffer probe; The sniffer probe comprises at least two separated arms, the test cavity is formed between the arms, and at least one of the arms is provided with an air inlet on a side facing the test cavity.

2. The sniffer probe according to claim 1, characterized in that The distance between adjacent shielding elements is less than or equal to 1 / 10 of the diameter of the air inlet.

3. The sniffer probe according to claim 2, characterized in that The sniffer tip is formed by at least one arm, wherein the shielding element protrudes from a side of the at least one arm facing the test cavity.

4. The sniffer probe according to claim 1, characterized in that A plurality of shielding elements surround the air inlet.

5. The sniffer probe according to any one of claims 1 to 4, characterized in that: A plurality of shielding elements are provided in the form of flexible fibers.

6. The sniffer probe according to claim 1, characterized in that At least two shielding elements of different lengths are provided; shielding elements of the same length are arranged in multiple rows, and multiple rows of long shielding elements are alternately arranged with multiple rows of short shielding elements.

7. The sniffer probe according to claim 1, characterized in that At least some of the shielding elements surround a majority of the test cavity.

8. The sniffer probe according to claim 5, characterized in that The air inlet is formed on an inner side of the corresponding arm facing the test cavity.

9. The sniffer probe according to claim 3, characterized in that: The shielding element is arranged only in an edge region of the inner side of the arm facing the test cavity, and this edge region delimits the test cavity from the external environment.

10. The sniffer probe according to claim 1, characterized in that: The shielding elements are arranged on two arms on opposite sides of the test cavity, and each of the shielding elements is close to the test cavity or shields the test cavity from the environment.

11. The sniffer probe according to claim 1, characterized in that: At least a portion of the shielding element extends to a center position of the test cavity.

12. The sniffer probe according to claim 1, characterized in that: The two arms are connected to each other in a fork-shaped manner at their rear ends, and an air inlet is provided at the front end opposite to the rear ends.

13. The sniffer probe according to claim 12, characterized in that: The two arms are in a U-shaped configuration.

14. The sniffer probe according to claim 8, characterized in that: The inner sides of the two arms are arranged parallel to each other in the front end region.

15. The sniffer probe according to claim 1, characterized in that The arms are connected at their rear end to a base element which comprises the main sniffing line and can be connected to a gas leak detector.

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