WO2014086455A1 - Device for connecting a high-pressure sensor - Google Patents

Abstract

The invention relates to a device (1) for connecting a high-pressure sensor (2) to a volume (3) under high pressure comprising a first component (4) corresponding to the high-pressure sensor (2) and a second component (5) corresponding to the volume (3), having at least two sealing rings (8, 13) made of an elastic material which in the fitted condition are clamped so as to form a seal between the first component (4) and the second component (5). The invention is characterised in that one of the components (5) is provided with an internal thread and one of the components (4) is provided with a corresponding external thread, wherein in the fitted condition the at least two sealing rings (8, 13) are disposed on the respectively opposite side of the thread (6).

Description

 Device for connecting a high-pressure sensor

The invention relates to a device for connecting a high-pressure sensor to a high-pressure volume according to the closer defined in the preamble of claim 1.

It is known from the prior art that gas sensors must be connected to a high-pressure volume and sealed accordingly. The point at which the high-pressure sensor is connected to the gas volume always represents a point which is critical in terms of tightness within the system. US 2004/0182705 A1 therefore describes a

Gas sensor, which is sealed by a plurality of sealing rings, which are formed compressed in both the axial and in the radial direction. The structure is comparatively complex and can only ensure a seal against the medium in the volume. Environmental influences such as

For example, occurring in the environment water or the like can enter from the opposite side in there or not poorly sealed sensor. This is particularly critical when different materials are used, for example, a light metal or a carbon fiber reinforced material on the one hand and a connecting element made of a steel alloy, a stainless steel or the like on the other side. Due to the different

Electronegativity values can then, especially when moisture penetrates, which serves as the electrolyte, lead to an electrochemical corrosivity between the two different materials.

The object of the invention is therefore to provide a device for connecting a high-pressure sensor to a high-pressure volume, which the avoids the above-mentioned disadvantages and ensures a simple, safe and reliable construction.

According to the invention this object is achieved by a device having the features in the characterizing part of claim 1. Advantageous embodiments and

Further developments of the device result from the dependent thereon

Dependent claims. Furthermore, a use of such a device is indicated.

In the device according to the invention is a with a high pressure sensor

corresponding component with a second volume-corresponding component, wherein, similar to the prior art, at least two

Sealing rings of an elastic material, which are pressed in the assembled state sealingly between the first and the second component, are provided.

According to the invention, it is now so that one of the components has an internal thread and one of the components has a corresponding external thread. The at least two sealing rings are arranged, at least in the mounted state, on the respective opposite side of the thread. About such an arrangement of the two sealing rings on the opposite sides of the thread is achieved that, from the side of the

Volume ago seen, a first seal in front of the thread and a second

Seal after the thread takes place. As a result, a very good seal is achieved, wherein the at least two sealing rings different sealing tasks

take over and can be optimized accordingly.

According to a particularly advantageous development of the device according to the invention, it is accordingly provided that the sealing ring on the side facing the volume is formed resistant to the medium in the volume, while the at least one other sealing ring against occurring in the environment media, especially water, resistant is. Such a seal with two different sealing rings allows, for example, in the sealing of a

High pressure sensor connection for a hydrogen sensor, the first one

Hydrogen volume facing sealing ring in such a way that it is highly resistant to hydrogen formed. For example, it can be made of PU or

preferably be formed of TPU. On the other hand, such a highly resistant to hydrogen seal would be against environmental influences, such as water, which, for example, in the cleaning of the device under high pressure on the other Sealing ring would be rinsed, not overly resistant. Therefore, the other sealing ring can be formed resistant to just these media, for example, a silicone rubber or fluoro-silicone rubber. The first seal then takes over the actual sealing against the gas under high pressure, while the other sealing ring takes over the sealing of the connection, namely the thread against environmental influences. By this structure, for example, a

Threaded steel or stainless steel in a tank, preferably a hydrogen tank, made of aluminum and / or carbon fiber reinforced plastic are screwed.

Due to the sealing by the opposite of the media occurring in the surrounding seal the penetration of water and moisture into the thread is reliably and reliably prevented, so that an electrolyte, which would be necessary for electrochemical corrosion, is not present and the materials accordingly despite their contact to each other and the different

Do not corrode electronegativity values.

In a very favorable development of the device according to the invention, provision is further made for the sealing ring, which is resistant to the media occurring in the environment, to be concavely curved in cross section at least on its side facing the one component. Such a concave curvature in the region of the abutment against a sealing surface makes it possible, in particular if the cross section in the region of the concave curvature is mirror-symmetrical to a mirror axis running centrally to the cross section and parallel to the axis of the thread, despite a radial direction or a directional component occurring in the radial direction

Strain on the sealing ring, for example, by spraying water from a high-pressure cleaner, deformation of the sealing ring typically not to a

Lifting of the sealing ring of the sealing surface leads, since by the concave shape even with a deformed sealing ring a plant is still given on this surface. This applies in particular to sealing rings, which in the axial direction have a significantly greater extent in their cross-section than in the radial direction. The structure can thus be designed so that it is designed very dense even in adverse conditions.

In a preferred development thereof, it can also be provided that the sealing ring which is resistant to the media occurring on its side arranged in the axial direction opposite the region with the concave curvature has a sealing lip has, which points in the intended installed state of the side of the axis of the thread to the outside. Such a sealing lip can also prevent the ingress of water safely and reliably, as they occur from the outside

Water pressure is pressed against the material of the component or the sealing surface and thus prevents ingress of water. Since two sealing lips are typically extremely complex in terms of manufacture and assembly, the sealing ring which is resistant to the media occurring in the environment is ideally designed such that it has the sealing lip at one axial end and the concave, in particular mirror-symmetrical, at its other axial end , Cross-section.

As an alternative to such a complexly shaped sealing ring would of course also a simple O-ring, preferably made of fluoro-silicone rubber, possible, which is also, on all sides, concave and mirror-symmetrical.

In a further very advantageous embodiment of the device according to the invention, it is further provided that the material of the opposite in the environment

occurring media resistant sealing ring is formed radially inside the sealing lip in the mounted state not over the entire circumference to a sealing surface fitting. The material in the radial direction within the sealing lip may, for example, have a plurality of grooves or openings, so that it does not bear sealingly on a sealing surface over the entire circumference. The seal in this area takes over the sealing lip, which has corresponding outward and seals in the usual way. If there is now an undesired but possibly safety-critical leak in the area of the other sealing ring sealing the volume, then the medium escaping from the volume, for example hydrogen, can penetrate approximately unimpeded through the threads screwed into one another and reaches the area in the area against that in the surroundings occurring media resistant sealing ring whose

Task it definitely should not be, this medium to the environment

seal. Accordingly, because of the material not resting against the sealing surface over the entire circumference, the medium can pass into the region directly below the sealing lip. From a corresponding overpressure then the sealing lip is raised, so as to ensure an outlet of the pressurized medium, such as hydrogen, to the outside. The device thus also serves as a safety valve, which from a certain overpressure, namely whenever the sealing ring which seals the volume fails, the medium can be blown outwards by allowing the sealing ring which is resistant to the media occurring in the environment, for example, by the embodiment described above, to permit a deliberate leak at a certain overpressure.

In an alternative embodiment of the device according to the invention, it may alternatively or optionally also be provided in addition that the resistant to the media occurring in the environment sealing ring is arranged in a sealing gap between the first and the second component, which is designed so that it expanded in the radial direction outside of the sealing ring in the assembled state, at least in one section. Such an extension of the sealing gap outside the sealing ring in the mounted state can be realized, for example, by a conical configuration of the sealing gap, so that it expands continuously, for example, to the outside. Likewise, it would be conceivable that the enlargement

stepped, or that one or more ideally radially extending channels are introduced into the sealing surface, which lie in the intended assembled state radially outside of the sealing ring, and which at least partially

To increase the cross section of the sealing gap.

In all described and conceivable embodiments of this extension of the sealing gap, it is now so that at an overpressure due to a failure or a leak in the region of the sealing ring, which seals the volume, a

Build up pressure. Such an overpressure which continues through the thread expands the sealing ring, which is resistant to the media in the environment, and moves it at least in sections radially outward. An extension of the sealing gap radially outside the position of the sealing ring in the intended use therefore leads to a deliberate leak between the sealing ring and the widened portion of the sealing gap, so that at a pressure sufficient to expand the sealing ring according far, a targeted release of the under pressure standing medium, for example of hydrogen, is realized. This expansion of the sealing ring in overpressure works both in O-rings, oblong elongated rings with two concave curvatures at their axial ends, as well as sealing rings with a concave curvature at its axial end and a sealing lip on the other side. This creates the possibility of a

Overpressure protection, comparable to the lifting lip in the top described embodiment created. The two variants could, as already mentioned, also be combined with one another.

In a further advantageous embodiment of the device according to the invention, it can also be provided that at least in the region of one of the sealing rings, preferably in the region of the volume sealing sealing ring, a stop element for limiting the axial travel of the components against each other during screwing is arranged. Such a stop element makes it possible to clamp the sealing rings only to a defined deformation and thereby to prevent damage to the sealing rings, for example, by over-tightening the two components via their threads against each other.

In an advantageous development thereof, it is provided that the

Stop element integral with one of the components, in particular with the

External thread having component is formed. Such a stop element may for example be integrated into the component so as to be available safely and reliably and without it being lost during assembly.

According to a particularly advantageous alternative development, the stop element is designed as an annular element, preferably made of a plastic, which is on / in one of the components up / inserted. Such a plugged or

Inserted stop element can simultaneously ensure, in addition to the formation of a stop element, that in the area in which the stop between the two components takes place, no damage to the components occurs. The device can be mounted and disassembled almost as often without a

Damage occurs, which the tightness in a subsequent assembly

could possibly jeopardize. If necessary, the ideally made of plastic stop element can be easily replaced.

According to an advantageous development, it can also be provided that the component with the external thread in its in the assembled state facing the other component area has a threadless extension following the external thread, which in particular as a stop element or for receiving the

annular stop element is formed. Such an extension of the thread or component without thread is ideally suited to form such a stop or aufzustecken an annular stop element, such as plastic, on it. It can be easily and efficiently manufactured during the production of the thread. The fact that the section is unthreaded ensures a plane bearing surface of the section, especially if it is itself formed as a stop element, whereby a secure and reliable stop over the entire peripheral surface can be realized away. Damage to the opposite surface, which is ideally planar in this case, can thus be almost excluded. This has an extremely beneficial effect on the possibility of disassembly and reassembly, with a variety of disassemblies and assemblies can be performed without causing a disadvantage in terms of tightness in a re-assembly occurs.

The device is particularly suitable for connecting a high-pressure sensor to a hydrogen system, as has already been indicated above. In such

Systems and the typically occurring pressures in hydrogen systems of, for example, 350 or 700 bar, a good seal with respect to the hydrogen is accordingly important, which can preferably be achieved by a seal having a very well resistant to hydrogen material. However, such a seal will typically be quite unstable to water, so that in the device according to the invention via a different seal, a seal against water and other media occurring in the environment takes place. Also, since the tanks or fittings used for the high pressure hydrogen are typically aluminum and / or carbon fiber reinforced plastics, it is critical that the seal against the ambient media, especially water, be extremely good at preventing any electrolyte between the threads and thereby safely and reliably prevent contact corrosion. A correspondingly good seal then allows the use of, for example, stainless steel in the component, which is screwed into the other component, for example made of aluminum, and which corresponds with the high-pressure sensor accordingly. The structure is simple, efficient, safe and reliable, in particular also, since it offers the possibility of integrating an overpressure safety device into the system, so that it is particularly suitable for a fuel cell system, especially for a

Fuel cell system used to provide electrical power, in particular electrical drive power, used in a vehicle. For such systems are correspondingly high safety requirements in a simple, compact and lightweight design, which are mandatory due to the use in a vehicle. All these requirements can be achieved by the invention

Fulfill device ideally.

Advantageous developments and refinements of the device according to the invention will become apparent from the exemplary embodiments, which are described in more detail below with reference to the figures.

Showing:

 Fig. 1 is a sectional view through a device according to the invention in one

 possible embodiment;

Fig. 2 shows a detail of the representation analogous to FIG. 1 in an alternative

 embodiment;

 3 shows a detail of the illustration analogous to FIG. 2 in a further alternative embodiment;

 FIG. 4 shows two further alternative embodiments of a detail from the device analogous to FIG. 1; FIG. and

Fig. 5 shows an alternative embodiment of a sealing ring.

In the illustration of Figure 1 is a sectional view through a device 1 for connecting a principle indicated high-pressure sensor 2 to a below

High-pressure standing volume 3, for example, a compressed gas storage for

Hydrogen in a fuel cell vehicle, shown. The device 1 consists essentially of a first component 4, which is connected to the high-pressure sensor 2

corresponds, and a second component 5, which corresponds to the volume 3, which in particular a connecting piece, for example a

High pressure hydrogen tanks or the like forms or is part of such.

In the region of the component 4, an external thread is provided, in the region of the component 5 has a bore with a corresponding internal thread, wherein due to the bolted state of the components 4, 5 shown in Figure 1, both threads are provided together only with a reference numeral 6. On the volume 3

facing side of the thread 6 is located in the first component 4 in the Substantial annular recess 7, in which a sealing ring 8 is arranged. This sealing ring 8 is designed to be resistant to the medium in the volume 3, that is to say relative to the hydrogen, as far as this is even possible with hydrogen. A suitable material for such a comparatively resistant to hydrogen continuously formed sealing ring 8 may be for example TPU. In order to prevent the sealing ring 8 from being more strongly squeezed during assembly of the device 1 than intended, a threadless extension 9 is formed following the external thread 6 which is applied to the first component 4 and which faces the second component 5 on the side facing the second component 5 most protruding part of the first component 4 forms and thus can serve as a stop element. Characterized in that the threadless extension 9 has no thread, its end can be formed flat, so that it cooperates with a likewise plan trained sealing surface 10, without that during assembly and subsequent disassembly a strong

Deterioration of the materials remains, which could possibly lead to leaks in the event of re-assembly. The stop element 9 may have a radially inwardly facing projection 11, so as to prevent the sealing ring 8 from falling out before mounting.

In addition to this sealing of the device 1 against the hydrogen by means of the sealing ring 8 must now also be provided for sealing against media occurring in the environment, in particular water, especially since typically the first component 4 is formed of a stainless steel, and the second component. 5

for example, consists of aluminum. To a contact corrosion in the field of

To exclude thread 6 safely and reliably, it must be ensured that no moisture penetrates into the thread 6, since this could serve as an electrolyte and thus would favor the contact corrosion.

In order to realize this seal against the environment, in the embodiment shown in the figure 1 in the first component 4, a further annular recess 12 is formed, in which one in relation to those in the environment

occurring media resistant sealing ring 13 is arranged. This sealing ring 13 may for example be designed as an O-ring. It may preferably be formed of silicone rubber or a fluoro-silicone rubber, in order to ensure a correspondingly good resistance to the media of the environment, in particular water,

exhibit. For example, water from a high-pressure cleaner safely and Reliable to be prevented by the sealing ring 13, at least in the full beam, while a shoulder 14 is formed outside the annular recess 12, which reduces the gap corresponding to the penetration of water under high pressure. The seal itself is then realized via the sealing ring 13 in a conventional manner. The sealing ring 13 is slightly smaller in its inner diameter than the external thread on the first component 4, so that by this configuration and the arrangement within the shoulder 14 of the sealing ring 13 during assembly safely and reliably remains on the component 4 and can not be lost.

An alternative embodiment of the area around the sealing ring 8 can now be seen in the illustration of FIG. Instead of the threadless extension 9, which also serves as a stop element, the threadless extension 9 is designed here with a significantly smaller diameter than the basic diameter of the external thread. This area is then a separate annular

Stop element 15, which is preferably formed of a plastic material, placed. This annular stop member 15 takes on the supporting forces and ensures a stop which prevents excessive squeezing of the sealing ring 8 safely and reliably. At the same time it avoids damage to the planar sealing surface 10 or the surface of the first component 4 when screwing due to its design made of plastic material, as impressions, which are caused in particular as a result of a repeated screwing in the surfaces safely through the annular stop member 15 made of a plastic material and reliably prevented. If the annular stop element 15 made of plastic after repeated assembly and disassembly be worn or damaged, then it can be easily replaced with a new, which can be plugged into the threadless extension 9 in a very simple manner.

A further alternative embodiment of the area already described and shown in FIG. 2 can be seen in the representation of FIG. The annular

Stop element 15 made of a plastic material is formed in this embodiment with a slightly larger wall thickness, so that the threadless extension 9 between the sealing ring 8 and the annular stop member 15 can be omitted entirely. This reduces the risk that a gap results due to tolerances on the sealing base, in which the sealing ring 8 could be extruded. This would have a damage of the sealing ring and a deterioration of the seal, at the latest after another reassembly, the result.

In the representation of FIG. 4, again a detail from the device 1 is taken up analogously to the representation in FIG. The section essentially shows the area around the sealing ring 13, wherein above a central axis 16 of the thread 6 another variant embodiment is shown as below this axis 16. However, the effect of both embodiments is the same. Both design variants have a much thinner shoulder 14 in the radial direction compared to the illustration in FIG. A sealing gap 17 between the first component 4 and the second component 5, in which the sealing ring 13 is arranged, is in both embodiments designed so that it expands at least partially outside of the sealing ring 13 in its intended use. In the representation above the axis 16, the extension takes place via at least one radially inwardly outwardly extending channel 18, which is arranged in the first component 4, and which is designed to be open to the other component 5. One or more such channels 18 could be arranged both in the component 4 and in the component 5 or in both components 4, 5. If there is now an overpressure in the region of the thread 6, because, for example, hydrogen has leaked through the sealing ring 8 or the sealing ring 8 is damaged accordingly, then the overpressure will expand the sealing ring 13 to the outside, so that the sealing ring 13 in the radial direction to the outside moved, for example, in the dashed position shown. He releases at least a portion of the channel 18, so that through this channel 18, the hydrogen can flow out and the pressure between the components 4, 5 is reduced. As a result, the safety of the device 1 can be increased accordingly.

In the lower half of the illustration in Figure 4, an alternative embodiment is shown. The sealing surface, which delimits the sealing gap 17 in the region of the first component 4, extends obliquely in the axial direction, so that a conical sealing gap thus arises. Again, it would of course be conceivable again, alternatively, to let the area in the region of the other component 5 or the area in the region of both components 4, 5 to extend obliquely accordingly. If the sealing ring 13 is now pressed outward into the position shown in dashed lines, it loses its pressure in the axial direction and no longer seals reliably. Between the sealing ring 13 and the material of the components 4, 5 then the gas under pressure can escape accordingly. Instead of a continuous cross-sectional widening, as shown in the lower half of Figure 3, would of course also a cross-sectional widening of the sealing gap 17, for example by means of one or more stages conceivable.

In the illustration of Figure 5, another possible embodiment of a sealing ring 13 for sealing the components 4, 5 is shown relative to media occurring in the environment. The sealing ring 13 comprises a sealing lip 19, which

For example, the second component 5 faces, and then the first component 4 facing the end with a concave curvature 20, which is preferably mirror-symmetrical to a mirror axis which extends in the axial direction and is arranged parallel to the axis 16 of the thread 6. This exemplary mounting direction of the sealing ring 13 could just as well be reversed, so that the sealing lip 19 in the first component 4 and the concave curvature 20 faces the second component 5. Preferably, the sealing ring 13 is typically installed so that a drainage of any penetrating liquid along the sealing lip 19 by gravity is possible. This preferred mounting position is shown in Figure 4 accordingly.

The concave curvature 20 allows the sealing ring 13, for example, at a

Exposure from the outside with high-pressure water, despite a

Deformation continue to rest by the concave dome 20 on the material, for example, the first component 4. At the same time then the sealing lip 19 is pressed securely and reliably against the second component 5 on the other side. In one embodiment, as is customary for example from the prior art, instead of the concave curvature 20, a convex curvature would be provided. In the case of a comparable pressurization, at least one of the edges of the convex curvature, for example, would lift off correspondingly from the material of the first component 4, which can lead to leaks.

In order to create the possibility in the case of the sealing ring shown in the illustration of FIG. 5 that overpressure occurring in the area of the thread 6 can escape safely and reliably through the sealing ring 13, the material of the sealing ring 13 is formed radially inside the sealing lip 19 so that this alternately consists of projections 21 and grooves 22 so that pressurized hydrogen in the region of the thread 6 lift the sealing lip 19 and flow out below the sealing lip 19 therethrough can. As material for the sealing ring 13 in the embodiment according to FIG. 5, silicone rubber or preferably fluoro-silicone rubber, for example, may in turn be used. Alternative materials, such as, for example, PU, TPU, graphite nanofiber materials, flexible graphite, which is also known as Grafoil, Sigraflex, Grafiflex, or other materials known to a person skilled in the art for this application, individually or in a suitable combination, or as a composite material are conceivable. wherein, if necessary, by a coating of the outer surface, the resistance to water as one of the crucial media in the vicinity of the device 1 can be increased if necessary.

Claims

Patent claims Device (1) for connecting a high-pressure sensor (2) to a volume (3) under high pressure, having a first with the high-pressure sensor (2) corresponding component (4) and a second component (5) corresponding to the volume (3), with at least two sealing rings (8, 13) made of an elastic material, which in the assembled state seal between the first component (4) and the second component (5) are braced, characterized in that one of the components (5) is provided with an internal thread and one of the components (4) is provided with a corresponding external thread, the at least two sealing rings (8, 13) being arranged on the opposite side of the thread (6) in the assembled state. Device (1) according to claim 1, characterized in that the sealing ring (8) on the volume (3) facing side is designed to be resistant to the medium in the volume, while the at least one other sealing ring (13) is designed to be resistant to media occurring in the environment, in particular water. Device (1) according to claim 2, characterized in that the sealing ring (13), which is designed to be resistant to media occurring in the environment, is concavely curved in cross-section at least on its side facing one of the components (4). 4. Device (1) according to claim 3, characterized in that the cross section in the area of the concave curvature (20) is designed to be mirror symmetrical to a mirror axis running centrally to the cross section and parallel to the axis (16) of the thread (6). 5. Device (1) according to claim 3 or 4, characterized in that the sealing ring (13), which is designed to be resistant to the media occurring in the environment, has a sealing lip (19) on its side arranged in the axial direction opposite the area (20) with the concave curvature, which, when installed as intended, extends from the side of the axis (16 ) points obliquely towards one of the components (5) towards the outside. 6. Device (1) according to claim 5, characterized in that the material of the sealing ring (5), which is designed to be resistant to the media occurring in the environment, does not lie radially within the sealing lip (19) over the entire circumference against a sealing surface when assembled is trained. 7. Device (1) according to one of claims 2 to 6, characterized in that the sealing ring (13), which is designed to be resistant to the media occurring in the environment, is arranged in a sealing gap (17) between the first component (4) and the second component (5), which is designed so that it is located in the radial direction outside the Sealing ring (13) expanded in at least one section in the assembled state. 8. Device (1) according to one of claims 1 to 7, characterized in that at least in the area of one of the sealing rings (8, 13), preferably in the area of the sealing ring (8) sealing the volume (3), a stop element (9, 15). Limiting the axial path of the components (4, 5) against each other Screwing is arranged. 9. Device (1) according to claim 8, characterized in that the stop element (9) is formed in one piece with one of the components (4, 5). 10. Device (1) according to claim 8, characterized in that the stop element (15) is designed as an annular element (15), in particular as an annular stop element made of plastic, which is plugged onto/into one of the components (4, 5). 11. Device (1) according to claim 8, 9 or 10 characterized in that the component (4) with the external thread has a threadless extension (9) in its assembled state facing the other component (5). Connection to the external thread, which in particular as Stop element (9) or is designed to receive the annular stop element (15). 12. Use of the device (1) for connecting a high-pressure sensor (2) to a hydrogen system, preferably in a fuel cell system, particularly preferably in a fuel cell system, which is used to provide electrical power, in particular electrical drive power, in a vehicle serves.