Pressure equalization device

Abstract

Pressure compensation device (10) for compensating an internal pressure in a receiving housing of an electrochemical or electrotechnical device, in particular for a battery housing, with a housing (20) which has at least one gas passage opening (26.2), wherein the gas passage opening (26.2) is blocked by means of a gas-permeable or gas-tight membrane (50) which is received in or on a membrane receptacle (26) in the housing (20), and wherein the membrane (50) is assigned a cutting element (30) which is designed and positioned such that, upon deformation of the membrane (30), the cutting element (30) destroys the membrane (50) at least at one point in order to prevent a flow connection between an inner side (21.2) of the pressure compensation device (10) and an outer side (21.1) of the pressure compensation device (10) through the gas passage opening (26.2), characterized in that the cutting element (30) is coupled directly or indirectly to the housing (20) by means of a spring section (31) in such a way that when the membrane (50) is deformed, the cutting element is adjusted at least in some areas.

Description

[0001] The invention relates to a pressure compensation device for compensating an internal pressure in a receiving housing of an electrochemical or electrotechnical device, in particular for a battery housing, with a housing which has at least one gas passage opening, wherein the gas passage opening is blocked by means of a gas-permeable or gas-tight membrane which is accommodated in or on a membrane receptacle in the housing, and wherein the membrane is assigned a cutting element which is designed and positioned such that upon deformation of the membrane the cutting element destroys the membrane at least at one point in order to create a flow connection between an inner side of the pressure compensation device and an outer side of the pressure compensation device through the gas passage opening.

[0002] Such a pressure equalization device is known from DE 10 2011 080 325 A1. This known pressure equalization device has a support element that has a flange section with bores for attachment to a battery housing. The support element covers the edge of an opening in the battery housing. The support element is connected to a membrane that blocks a gas passage opening in the support element. The membrane is stretched between the support element and a clamping piece and held in a circumferentially sealed manner. A housing-like protective element is also used, which has a cutting element in a central area. This cutting element is opposite the membrane. The protective element serves to prevent access to the membrane from the outside of the pressure equalization device. The protective element has gas passage openings. The membrane is gas-permeable but essentially water-repellent.The water-repellent function is such that water from the environment cannot, or only to a limited extent, penetrate from the outside to the inside. During normal operation, gas equilibrium can take place between the environment and the battery casing via the membrane. This is possible because the membrane is permeable to gas. If a sudden bursting pressure occurs, for example due to a fault in the battery casing, the membrane bulges outwards. A gap is provided between the cutting element and the outside of the membrane which defines the permissible deformation of the membrane in such a case of damage. If the membrane bulges beyond the permissible deformation, it strikes the cutting element, which is designed as a point. The cutting element damages the membrane, causing it to rupture. The gas can then quickly escape from the battery casing through the gas passage opening into the environment.This prevents the battery casing from exploding.

[0003] The pressure compensation device known from the prior art is complex in design. Furthermore, the inevitable dimensional tolerances between the individual device components do not ensure that the cutting element is always at exactly the same distance from the surface of the diaphragm in different pressure compensation devices of the same design. Therefore, the bursting behavior in the event of an overload cannot be reproduced exactly.

[0004] It is therefore an object of the invention to provide a stable pressure compensation device of the type mentioned at the outset, which ensures reproducible bursting behavior with little parts and assembly effort.

[0005] This object is achieved in that the cutting element is coupled directly or indirectly to the housing by means of a spring section in such a way that when the diaphragm is deformed, the cutting element is adjusted at least in part. According to the invention, reproducible bursting behavior is ensured by the spring behavior of the spring section. In particular, for example, a spring characteristic can be set using the spring section or a spring characteristic is produced using the spring section. As the deformation of the diaphragm increases, the counterforce on the diaphragm provided by the spring section also increases. The spring force of the spring section is transferred to the cutting element and thus rests against a cutting edge of the cutting element. From a certain adjustment path of the cutting element, the spring force becomes so high that the cutting edge cuts the diaphragm and this then releases the gas passage opening.

[0006] In order to ensure a defined deflection process for the cutting element, it can be provided that the cutting element has a deflection piece directly or indirectly connected to the cutting element, with which it rests against the membrane at least in one operating position of the membrane.

[0007] In this case, it can be provided, in particular, that the deflection piece rests against the diaphragm, particularly flatly, in the non-pressurized home position of the diaphragm, especially when the same ambient pressure prevails on the inside and outside. In this case, the deflection piece is already precisely aligned with the diaphragm in the home position, resulting in particularly reproducible bursting behavior.

[0008] Surprisingly, a particularly good functionality for the cutting element results if it is provided that the deflection piece and / or the spring section of the cutting element is / are connected to the membrane at least in some areas, in particular is / are connected to the membrane in a form-fitting manner.

[0009] To reduce the parts and assembly effort, the cutting element can be connected to the housing in one piece.

[0010] In order to realize a space-saving pressure compensation device, it can be provided that the gas passage opening is delimited by an inner wall of the housing, wherein it is preferably provided that the inner wall is formed circumferentially, and that the cutting element protrudes from the inner wall in the direction of the gas passage opening and preferably protrudes from the inner wall in the shape of a tongue.

[0011] A pressure compensation device according to the invention can be such that the cutting element has edges on opposite sides that laterally delimit the cutting element, and that the cutting element is directly or indirectly adjacent to the edges at a distance from the inner wall. If it is additionally provided that the edges converge at least partially, preferably in the direction from the inner wall to the free end of the cutting element, then a defined cutting element can be created in a simple manner in the region of the converging end sections of the edges. Within the scope of the invention, an edge or edges can each have or form at least one cutting element.

[0012] However, according to the invention, it can also be provided that at least the free end of the cutting element and / or the edges and / or another region of the cutting element arranged at a distance from the inner wall of the housing has or forms a cutting edge.

[0013] According to the invention, it can also be provided that the housing has a membrane receptacle with a connecting section, and that the membrane is connected all the way around to the connecting section by a fastening section. This results in a simple design. In particular, it can also be provided that the membrane is back-injected into the housing using a plastic injection molding process. In this case, the connection and sealing of the membrane to the housing is integrated into the injection molding process. In this case, the membrane is then firmly bonded to the housing. Within the scope of the invention, however, it is also possible for the membrane to be connected to a manufactured housing, in particular to be firmly bonded. Within the scope of the invention, it can also preferably be provided that the contact section merges into the connecting section in a flat manner. This enables the membrane to fit precisely against the contact section.It is particularly advantageous if the contact section merges seamlessly into the connecting section, so that these two component areas form a uniform surface.

[0014] A conceivable variant of the invention is such that the membrane has an outer membrane side and, opposite it, an inner membrane side, that the outer membrane side faces the outer side of the housing and the inner membrane side faces the inner side of the housing, and that the cutting element faces the outer membrane side, in particular rests on it in the non-pressurized basic position of the membrane.

[0015] According to one possible variant of the invention, a travel limiter can be provided which holds a stop spaced from the cutting element towards the outside of the housing, and which the cutting element strikes against the stop upon deformation of the diaphragm. In this case, the pressure compensation device can be designed in particular such that the diaphragm deforms during operation. The deformation of the diaphragm also enables adjustment of the cutting element. As described above, the cutting element adjusts itself against the force of the spring section. This makes it possible to realize a spring characteristic with a corresponding force acting on the cutting edge of the cutting element.As soon as the cutting element hits the stop, a steep increase in the force acting on the cutting element's cutting edge is generated in the force-spring diagram, and the membrane is subsequently destroyed along with the cutting element at an excessively high pressure. This allows for a particularly reliable, reproducible bursting behavior.

[0016] This results in a simple design with low parts and assembly costs if the travel limiter is connected to the housing in one piece by means of a connecting section.

[0017] Furthermore, a compact design can be achieved by holding the stop of the travel limiter by means of a spacer at a distance from the inner wall of the housing, which at least partially forms the gas passage opening.

[0018] One conceivable variant of the invention is such that the housing has a sealing section with a circumferential seal and / or an energy director, wherein the seal and / or the energy director is arranged as a separate component in the region of a mounting surface, or that the seal and / or the energy director is formed integrally with the housing in the region of a mounting surface. The surface that serves to support the pressure compensation device on the receiving housing of the electrochemical or electrotechnical device can be used as the mounting surface. A circumferential projection, for example, can be used as the energy director. This can be used to melt in the connection area between the receiving housing and the housing in order to thereby create a connection and / or seal.It is conceivable that a material-to-material bond is created, for example, by means of ultrasonic welding, laser welding, or friction welding. It is also conceivable that the joining partners are joined by cold or hot caulking. Furthermore, it is also conceivable that a material-to-material bond is created between the joining partners.

[0019] Within the scope of the invention, the cutting edge of the cutting element can be a linear or differently shaped cutting edge. Furthermore, the cutting edge of the cutting element can also be a point-shaped cutting edge.

[0020] Within the scope of the invention, the membrane can be designed to be waterproof or essentially waterproof. The membrane can be designed, in particular, as a flat element, in particular as a plastic film. The membrane can be made of a polyester material, for example, polyethylene terephthalate or polycarbonate, or it can be made entirely of such a material.

[0021] The membrane is preferably designed in the shape of a circular disc. This results in advantageous properties when the membrane is deformed.

[0022] The invention is explained in more detail below with reference to exemplary embodiments illustrated in the drawings. They show: Fig. 1 in perspective view a first embodiment of a pressure compensation device, Fig. 2 the pressure compensation device according to Fig. 1 in full cut, Fig. 3 in side view a further design variant of a pressure compensation device, Fig. 4 the pressure compensation device according to Fig. 3 in top view, Fig. 5 a 3rd embodiment of a pressure compensation device in perspective view and in full section along the Fig. 6 with IV-IV marked cutting line and Fig. 6 the pressure compensation device according to Fig. 5 in view from below.

[0023] Fig. Figure 1 shows a perspective view of a pressure compensation device 10. This pressure compensation device 10 has a housing 20. The housing 20 forms an outer side 20.1 and an inner side 20.2.

[0024] If the housing 20 is operationally installed with a receiving housing, in particular an electrochemical or electrotechnical device, for example a battery housing, the inner side 20.2 is assigned to the interior of the receiving housing. The outer side 20.1, on the other hand, is assigned to the interior of the receiving housing, facing away from the environment.

[0025] In the area of ​​the outer side 20.1, the housing 20 forms a cover 21. This is closed at the top by a cover surface 24. Opposite the cover surface 24, the housing 20 has a sealing section 22 on the cover 21.

[0026] The sealing section 22 can be formed as an annular projection on the housing 20 and preferably projects in the radial direction beyond an outer side of the housing 20.

[0027] The sealing section 22 forms a mounting surface 22.1 facing the inner side 20.2. This mounting surface 22.1 is preferably designed as a closed, annular surface that more preferably extends radially. A seal can be provided circumferentially in the area of ​​the mounting surface 22.1, which seal is molded, for example, using a two-component injection molding process in the area of ​​the sealing section 22 and protrudes toward the inner side 20.2.

[0028] In addition or alternatively to the seal, an energy director 22.2 can also be provided protruding from the mounting surface 22.1, as Fig. 2. The energy director 22.2 can be designed as a circumferential bead.

[0029] For a compact design, the cover surface 24 of the housing 20 preferably merges into an outer wall 23 of the cover 21 via a rounded transition.

[0030] The housing 20 forms an inner wall 25 which surrounds a gas passage opening 26.2.

[0031] The gas passage opening 26.2 can be closed by a membrane 50. The membrane 50 is designed as a flat element and preferably consists of a gas-permeable or gas-tight plastic film. The membrane 50 is essentially watertight and preferably tear-resistant and sufficiently strong to prevent accidental failure of the membrane 50 due to exposure to water pressure from the outer side 20.1.

[0032] The membrane 50 has an outer side 51 facing the outer side 20.1 of the housing 20. Opposite the outer side 51, the membrane 50 has an inner side 52 facing the inner side 20.2 of the housing 20.

[0033] How Fig. As can be seen in Figure 2, the membrane 50 can have a circumferential fastening section 53, which can be particularly annular. With this fastening section 53, the membrane 50 is connected in a gas-tight manner to a connecting section 26.1 of a membrane receptacle 26, preferably by a material connection. In particular, the membrane 50 can be back-injected onto the housing 20 using a plastic injection molding process.

[0034] The connecting section 26.2 is formed as an annular circumferential surface 26.1 on the membrane receptacle 26. In particular, the connecting section 26.1 extends annularly around the gas passage opening 26.2.

[0035] The Fig. 1 and Fig. 2 further show that a cutting element 30 is provided on the housing 20, which is preferably connected in one piece with the housing 20. Particularly preferably, the cutting element 30 is connected in one piece with the inner wall 25 of the housing 20.

[0036] As the drawings show, the cutting element 30 is connected to the housing 20 via a spring portion 31. Furthermore, the entire cutting element 30 can also be designed to be resilient or form the spring portion 31.

[0037] The cutting element 30 has a cutting edge 34. The cutting edge 34 can be point-shaped, linear, curved, or otherwise formed.

[0038] The cutting element 30 can, as shown in the drawings, protrude in a tongue-like manner from the housing 20, in particular from the inner wall 25, in particular protruding radially inwards into the region of the gas passage opening 26.2.

[0039] As the Fig. 1 and Fig. 2, the cutting element 30 can have edges 32, 33 on opposite sides in the circumferential direction of the wall 25. These two edges 32, 33 preferably converge from the connection point to the housing 20 toward the free end of the cutting element 30. A convexly curved contour is arranged at the free end of the cutting element 30, which forms the cutting edge 34, preferably with an arcuate cutting edge 34. As mentioned above, however, the cutting edge 34 can also have a different contour.

[0040] Fig. 2 shows that the cutting element 30 forms a contact section 35 on its side facing the inner side 20.2 of the housing 20. This contact section 35 rests on the membrane outer side 51. Preferably, the contact section 35 rests on the membrane outer side 51 when the pressure compensation device 10 is in the depressurized state. Particularly preferably, the contact section 35 can be integrally connected, at least in some areas, to the membrane outer side 51.

[0041] Fig. Figure 2 further shows that the underside of the contact section 35 forms a surface that transitions smoothly into the connecting section 26.1. Across this connection point, a material connection can be established between the membrane outer side 51 and the cutting element 30 or the connecting section 26.1.

[0042] The cutting element 30 forms a deflection piece 36 that faces the outer side 20.1 of the housing 20.

[0043] A travel limiter 40 can be provided on the housing 20. The travel limiter 40 can be designed as a separate component and connected to the housing 20 via a connecting section 42. Preferably, the travel limiter 40 can also be integrally connected to the housing 20 via this connecting section 42.

[0044] The travel limiter 20 has a stop 44, which is preferably held at a distance from the housing contour, preferably at a distance from the inner wall 25, by means of a spacer 43.

[0045] The travel limiter 40 is arranged at a distance from the cutting element 30 toward the outer side 20.1 of the housing 20. The travel limiter 40 can be positioned opposite the deflection piece 36 of the cutting element 30 with a bottom side 41.

[0046] For assembly, the pressure compensation device 10 is inserted into an opening in the housing of an electrical or electrochemical component. The mounting surface 22.1 covers the edge of this opening. Energy is introduced into the energy director 22.2 via a suitable energy-generating device, such as a laser welder or an ultrasonic welder. This melts and bonds firmly to the housing in the area of ​​the mounting surface 22.1. This creates a tightly sealed, all-round connection between the housing 20 and the housing.

[0047] During operation, the pressure in the housing changes due to operational conditions. If the pressure in the housing increases, the diaphragm 50 bulges toward the outer side 20.1. The cutting element 30 is deflected elastically at its spring section 31 toward the outer side 20.1. If the pressure in the housing decreases, the diaphragm 50 bulges toward the inner side 20.2.

[0048] If an impermissibly high burst pressure develops in the housing, the diaphragm 50 bulges toward the outer side 20.1. The cutting element 30 is deflected again until its deflection piece 36 hits the stop 44 of the travel limiter 40. At this point, the cutting element 30 offers high resistance to the diaphragm 50. This resistance causes the cutting edge 34 to cut through the diaphragm 50, causing it to rupture. This allows the internal pressure in the housing to be released via the gas passage opening 26.2.

[0049] It can also be provided that the cutting element 30 and the spring portion 31 are designed such that the cutting element 34 already cuts the membrane 50 before the deflection piece 36 hits the stop 44. In this case, the travel limiter 40 then forms a safety feature that ensures that the membrane 50 is destroyed in any case if an impermissibly high pressure develops in the receiving housing.

[0050] In the Fig. 3 and Fig. 4 shows a further variant of a pressure compensation device 10. This pressure compensation device 10 corresponds in its construction to the pressure compensation device 10 according to the Fig. 1 and Fig. 2. In order to avoid repetition, reference may therefore be made to the above statements.

[0051] In contrast to the design variant according to the Fig. 1 and Fig. 2, the pressure compensation device 10 according to the Fig. 3 and Fig. 4, however, does not have a travel limiter 40. Accordingly, the cutting element 30 or the spring section 31 are designed such that in the event of an inadmissible deformation of the membrane, the cutting element 34 reliably destroys the membrane 50.

[0052] In the Fig. 5 and Fig. 6 shows a further embodiment of a pressure compensation device 10. In principle, this pressure compensation device 10 corresponds to the pressure compensation device 10 according to the Fig. 3 and Fig. 4, or according to the Fig. 1 and Fig. 2, which is why reference is made to the above explanations. Therefore, only the differences between the different versions are explained below.

[0053] How Fig. As shown in Figure 6, the cover has a tool holder on its outer circumference for mounting the pressure compensation device 10. In particular, the tool holder is designed as an external hexagon.

[0054] In the area of ​​the inner side 20.2 of the housing 20, the pressure compensation device 10 has a protruding, molded-on fastening part 28. With this fastening part 28, the pressure compensation device 10 can be mounted in the opening of the receiving housing. Preferably, the fastening part 28 has a threaded portion 28.1, which is preferably designed as an external thread. With this external thread, the housing 20 can be screwed into an internal thread of the receiving housing. The fastening part 28 can have a circumferential inner wall, resulting in a gas passage area that is in gas-conducting connection with the gas passage opening 26.2 of the housing 20.

[0055] In the area of ​​the outer side 20.1, as Fig. 5, a connecting piece 27 may be integrally formed. The connecting piece 27 forms a discharge area 27.1 surrounding a gas duct 27.3. The gas duct 27.3 may be connected to the gas passage opening 26.2 in an air-conducting manner. At its free end, the connecting piece 27 forms a connecting piece 27.2 with an outlet opening 27.4. A suitable discharge line can be attached in the area of ​​the connecting piece 27.2.

[0056] The drawings further illustrate that a circumferential sealing section 22, for example, with a circumferential groove, can be provided in the area of ​​the mounting surface 22.1. A seal can be inserted into this circumferential groove.

[0057] It is also conceivable that a sealing element is formed onto the sealing section, in particular into the circumferential groove, in particular formed onto the housing 20 using a two-component injection molding process or foamed into the groove.

[0058] As already explained above, within the scope of the invention the housing 20 can be made of plastic, in particular can be formed as a one-piece plastic injection-molded part. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2011 080 325 A1

[0002]

Claims

[1] Pressure compensation device (10) for compensating an internal pressure in a receiving housing of an electrochemical or electrotechnical device, in particular for a battery housing, with a housing (20) having at least one gas passage opening (26.2), wherein the gas passage opening (26.2) is blocked by means of a gas-permeable or gas-tight membrane (50) which is received in or on a membrane receptacle (26) in the housing (20), and wherein the membrane (50) is assigned a cutting element (30) which is designed and positioned such that, upon deformation of the membrane (30), the cutting element (30) destroys the membrane (50) at least at one point in order to create a flow connection between an inner side (21.2) of the pressure compensation device (10) and an outer side (21.1) of the pressure compensation device (10) through the gas passage opening (26.2), characterized bythat the cutting element (30) is coupled directly or indirectly to the housing (20) by means of a spring section (31) in such a way that when the membrane (50) is deformed, the cutting element is adjusted at least in some areas. [2] Pressure compensation device (10) according to claim 1, characterized by that the cutting element (30) has a deflection piece (36) directly or indirectly adjoining the cutting element (30), with which it rests against the membrane (50) at least in an operating position of the membrane (50). [3] Pressure compensation device (10) according to claim 2, characterized by that the deflection piece (36) in the non-pressurized basic position of the membrane (50), in particular when the same ambient pressure is present in the area of ​​the inner side (20.2) and the outer side (20.1), the deflection piece (36) rests against the membrane, in particular rests against it flatly. [4] Pressure compensation device (10) according to one of claims 2 or 3, characterized bythat the deflection piece (36) and / or the spring section (31) of the cutting element (30) is / are connected at least in regions to the membrane (50), in particular is / are connected to the membrane (50) in a form-fitting manner. [5] Pressure compensation device (10) according to one of claims 1 to 4, characterized by that the cutting element (30) is integrally connected to the housing (20). [6] Pressure compensation device (10) according to one of claims 1 to 5, characterized by that the gas passage opening (26.2) is delimited by an inner wall (25) of the housing (20), wherein it is preferably provided that the inner wall (25) is formed circumferentially, and that the cutting element (30) protrudes from the inner wall in the direction of the gas passage opening (26.2) and preferably protrudes from the inner wall (25) in a tongue-like manner. [7] Pressure compensation device (10) according to one of claims 5 or 6, characterized bythat the cutting element (30) has edges (32, 33) on opposite sides which laterally delimit the cutting element (30), and that the cutting element (34) adjoins the edges (32, 33) directly or indirectly at a distance from the inner wall, and wherein the edges (32, 33) preferably converge at least in regions in the direction from the inner wall (25) to the free end of the cutting element (30). [8] Pressure compensation device (10) according to one of the preceding claims, characterized by that at least the free end of the cutting element (30) and / or the edges (32) and / or another region of the cutting element (30) arranged at a distance from the inner wall of the housing (20) has or forms a cutting edge (34). [9] Pressure compensation device (10) according to one of the preceding claims, characterized bythat the housing (20) has a membrane receptacle (26) with a connecting section (26.1), that the membrane (50) is connected to the connecting section (26.1) by a fastening section (53) in a circumferential manner, in particular is connected by a material fit, and that the contact section (35) preferably merges into the connecting section (26.1) in a planar manner. [10] Pressure compensation device (10) according to one of claims 1 to 9, characterized by that the membrane (50) has an outer membrane side (51) and, opposite it, an inner membrane side (52), that the outer membrane side (51) faces the outer side (20.1) of the housing (20) and the inner membrane side (52) faces the inner side (20.2) of the housing (20), and that the cutting element (30) is opposite the outer membrane side (51), in particular rests on it in the non-pressurized basic position of the membrane (50). [11] Pressure compensation device (10) according to one of claims 1 to 10, characterized bythat a travel limiter (40) is provided which holds a stop (44) at a distance from the cutting element (30) in the direction of the outer side (20.1) of the housing (20), and that the cutting element (30) strikes the stop (44) when the membrane (50) is deformed. [12] Pressure compensation device (10) according to claim 11, characterized by that the travel limiter (40) is connected in one piece to the housing (20) by means of a connecting section (42). [13] Pressure compensation device (10) according to claim 11 or 12, characterized by that the stop (44) of the travel limiter (40) is held by means of a spacer (43) at a distance from the inner wall (23) of the housing (20), which at least partially forms the gas passage opening. [14] Pressure compensation device (10) according to one of claims 1 to 13, characterized bythat the housing (20) has a sealing section (22) with a circumferential seal and / or an energy director (22.2), wherein the seal and / or the energy director (22.2) is arranged as a separate component in the region of a mounting surface (22.1), or that the seal and / or the energy director (22.2) is formed integrally with the housing (20) in the region of a mounting surface (22.1). [15] Pressure compensation device (10) according to one of claims 1 to 14, characterized by that the housing (20) has a one-piece molded cover (21) which is preferably designed to run circumferentially around the gas passage opening (26.2) and which projects radially outwards on the housing (20). [16] Pressure compensation device (10) according to one of claims 1 to 15, characterized bythat in the area of ​​the outer side (20.1) of the housing a protruding connecting piece (27) is formed, which is in gas-conducting connection with a discharge area (27.1) with the gas passage opening (26.2) and forms a gas guide (27.3) here, wherein the gas guide 27.3 forms an outlet opening (27.4). [17] Pressure compensation device according to one of claims 1 to 16, characterized by in that in the region of the inner side (20.2) of the housing (20) a fastening part (28) is arranged in a protruding manner, which fastening part is designed to form a connection between the housing (20) and the receiving housing of the electrochemical or electrotechnical device, wherein it is preferably provided that the fastening part (28) has a threaded section (28.1), preferably an external thread, and wherein the fastening part (28) delimits a gas passage with an inner wall (28.2) which is in gas-conducting connection with the gas passage opening (26.2).

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