DE102014016976A1 - Check valve for high pressure gas applications - Google Patents

Abstract

The invention relates to a check valve (9) for high-pressure gas applications with a first and a second housing part (10.1, 10.2) which together form a valve housing (10), with a valve seat (16) in the valve housing (10) and one in the valve housing (10). 10) against the force of a spring (23) movable valve body (20). The check valve according to the invention is characterized in that a metallic seal (28) is provided between the two housing parts (10.1, 10.2).

Description

The invention relates to a check valve for high-pressure gas applications according to the closer defined in the preamble of claim 1. Art also relates to the use of such a check valve.

Check valves are known from the general state of the art. They typically have a valve body which is pressed by the force of a spring element against a valve seat, and which is lifted by the flow in a direction against the force of the spring from the valve seat, thereby releasing a flow cross-section. In particular, for high-pressure gas applications such check valves must meet various requirements, which usually lead to very complex approaches and make the check valves accordingly expensive, complicated and difficult. In particular, for use in high-pressure hydrogen, ie hydrogen applications with a nominal pressure of more than 50 MPa, in particular the currently common nominal pressure of 70 MPa, check valves are complex and complex.

For further state of the art, for example, for another application to the DE 10 2011 121 467 B4 to get expelled. This retention valve, which is also referred to as a pilot valve, serves, for example, as a removal valve for gases under high pressure from a compressed gas storage. It has a correspondingly complex structure with a plurality of elastomer seals executed. In particular, for hydrogen applications, the resulting seal is generally insufficient.

In addition, on the JP 2009-145 120 A to get expelled. This also has a comparable bleed valve, which in particular has an important in hydrogen leakage well in the area detected with a corresponding detector hydrogen leakage and / or leaking hydrogen can be collected. Similar holes also shows the previously described valve.

Furthermore, from the US 2001/0266472 A1 a check valve known, which has a correspondingly complex structure. In particular, the structure has the task of ensuring high functionality and minimizing wear in the valve, even with fluids which carry contaminants with them. For this reason, it uses a separate sealing ring made of a metallic material for connection to a flange e.

The object of the present invention is now to provide a check valve for high-pressure gas applications according to the preamble of claim 1, which can be constructed easily and efficiently, and which is a very good sealing of the valve housing from the environment over a very large operating range - in terms of pressures and Temperatures guaranteed.

According to the invention this object is achieved by a check valve having the features in the characterizing part of claim 1. Advantageous embodiments and further developments emerge from the subclaims dependent thereon. In claim 12, a particularly preferred use for the check valve is also indicated.

The check valve for high pressure gas applications according to the invention consists, similar to similar valves of the prior art of two housing parts, which together form the valve housing. Therein is a valve seat and a valve body movable against the force of a spring valve body which is adapted to cooperate sealingly with the valve seat and which can be lifted against the force of the spring from the valve seat. According to the invention, it is now so that a metallic seal is provided between the two housing parts. Such a metallic seal between the housing parts allows a very good and efficient seal with very few components and does not have the risk that sealing elements could be damaged by incorrect assembly, which is a not to be underestimated danger when using elastomeric sealing elements. In addition, a metallic seal over a very large temperature ranges ensure high tightness. Especially in vehicle applications of the check valve temperature ranges between -50 ° C and + 100 ° C must be covered. Typically used elastomeric gaskets, which have a high density, for example, against hydrogen as the gas of high pressure gas application, typically have a rather high glass transition temperature, so that such gaskets become brittle and hard very quickly at low temperatures. They are then no longer suitable for adequate sealing. The use of a metallic seal between the housing parts obviates these problems and provides a structure which can be mounted extremely tightly over a wide range of applications in terms of temperature and pressure.

According to a very advantageous development of the check valve according to the invention, it can now also be provided that the metallic seal consists of a one-piece formed with the housing parts circumferential tapered groove on the one hand and a spherical surface portion on the other. In particular, this one-piece integration of a groove in the one housing part and a projecting cross-section spherical portion in the other housing part allows an extremely simple installation, since the corresponding necessary for the sealing elements are already integrated into the housing parts. The housing parts then only have to be connected to one another, typically with the specified tightening torque, typically by screwing in order to ensure a secure and reliable sealing. For this purpose, no additional components, such as an inserted seal or the like, necessary.

Another very favorable embodiment provides that the valve seat is formed by a body pressed into one of the housing parts. Such a valve seat pressed into the valve housing allows a very good internal sealing of the check valve, since the valve seat outside the housing part can be correspondingly easily machined with comparatively high precision and then pressed into the housing part. An integrally manufactured in the housing part seat would be due to the cramped space in the interior of the housing part in terms of processing significantly more complex, especially if comparable qualities of the processing to be achieved.

The pressed body with the valve seat can have a circumferential groove on the side facing away from the flow direction in the body having the valve seat. Such a circumferential groove allows the function of a pressure activation, which leads to an increased sealing effect of the valve body on the valve seat.

The valve body in the check valve according to the invention can be formed according to an advantageous development by a streamlined in the direction of the inflowing gas formation of a piston. Such a streamlined in the direction of the inflowing gas piston allows a low flow resistance of the check valve when it is pressed accordingly and flows through the gas under high pressure. On the other hand, the piston shape allows a very good guidance within the check valve, so that a tilting is counteracted efficiently, yet a lower flow resistance can be realized, as would be the case for example with a ball. Ideally, the streamlined configuration of the piston is designed in the manner of a dolphin nose, which represents a known streamlined cross-section, which has extremely favorable flow characteristics.

A further very advantageous embodiment of the check valve according to the invention, it also provides that the piston between the formed as a valve body streamlined portion and a spring leading portion has flow openings. The flow thus does not take place along the piston, but this has corresponding openings behind the valve body, so that the gas which has flowed around the serving as a valve body flow-line portion, flows into the interior of the piston and from there on. This allows in return, according to a very advantageous development that the piston on its lying in the direction of the streamlined portion end a projection z. B. a contact surface or abutment edge as a stop or end stop for the spring on the one hand and as a first guide relative to the valve housing on the other hand, and that the piston is guided at its other end in the manner of a sliding seal in the valve housing. In particular, in combination with the flow through the piston in its interior so creates a structure which a spring, such as a coil spring, between the valve housing and the exterior of the piston performs very well, and thus provides good functionality without the risk of tilting ,

A very advantageous development of the check valve according to the invention now also provides that the valve housing on its first side in the flow direction has an external thread and on its second side has an internal thread as a connection. This configuration with an internal thread on one side and an external thread on the other side ensures that the check valve is always mounted in the correct direction, since incorrect assembly due to the then non-co-operating thread is excluded from its connection. This setup is also called "poka yoke design".

Another extremely favorable embodiment of the check valve according to the invention, it also provides that in one of the housing parts on the side facing away from the gas of the metallic seal, a connection bore is formed to the environment. Such a leakage bore is particularly advantageous in hydrogen applications. About such a hole may be discharged through the metallic seal gas leaking gas leaks to the outside. The targeted discharge into one certain area in the exterior of the valve housing is a safety advantage. In addition, the targeted discharge into a corresponding area also allows that by a z. B. manually guided leakage probe leaks in the metallic seal between the housing parts of the check valve can be found quickly and easily.

According to a continuation of this idea, it is also provided that the connecting hole ends in a circumferential groove around the valve housing, in which a sealing ring is inserted under bias. Such a groove with a sealing ring inserted therein under bias allows a very simple and efficient sealing of the groove ending in the connection hole, for example against moisture, contamination or the like, as by the outside inserted sealing ring, which have no sealing requirements against the gas, ie in particular to hydrogen must be able to be sealed very easily and efficiently. In particular, here a sealing ring made of a silicone rubber can be used, which has a high elasticity even at very low temperatures and over all temperatures provides a good seal against moisture, spray, dirt and the like.

As already mentioned, the check valve according to the invention can be used in particular in a high-pressure hydrogen system. According to an advantageous use of the check valve according to the invention, it is therefore intended that this is used in a hydrogen high-pressure system. This high-pressure hydrogen system can be arranged in particular in a vehicle in which particularly high demands are placed on the tightness over a high temperature range. In particular, for such applications, the simple, lightweight and therefore inexpensive to produce and to be mounted check valve is ideally suited.

Further advantageous embodiments of the check valve according to the invention and its use will become apparent from the embodiment, which is described below with reference to the figures.

Showing:

1 a principle indicated vehicle with a fuel cell system, which is supplied by a high-pressure hydrogen system with fuel; and

2 an illustration of a possible embodiment of a check valve according to the invention in an open position above the center line and a closed position below the center line.

In the presentation of the 1 is very heavily schematized a vehicle 1 to recognize which via an electric drive motor 2 should be driven. The power for the electric drive motor 2 is about a power electronics 3 prepared and via a fuel cell 4 provided. The fuel cell 4 is for this purpose in a conventional manner via an air conveyor 5 supplied with air as an oxygen supplier on its cathode side. On the anode side, the fuel cell 4 Hydrogen from a compressed gas storage 6 fed. The hydrogen passes through a tank valve 7 at the compressed gas storage 6 and via an indicated pressure regulating and dosing unit 8th into the fuel cell 4 , Exhaust gases from the fuel cell 4 are discharged directly into the environment in the embodiment shown here. This structure is extremely simplified. The person skilled in the art is fuel cell systems for vehicles 1 but familiar so that he knows variants and alternatives, for example, in terms of gas routing, the use of fuel cell exhaust gases and the like anyway. Since this is of minor importance to the present invention, it need not be discussed further.

The hydrogen system in the vehicle 1 is designed as a high pressure system. The hydrogen in the compressed gas storage 6 is stored at a nominal pressure of 70 MPa. Within this hydrogen high-pressure system, there are typically several metering and control valves. Moreover, it is characteristic of such high-pressure hydrogen systems that these at least one check valve 9 even if this is in the presentation of the 1 not explicitly shown and recognizable. To such check valves 9 now high demands are made on the one hand, the pressure loss generated by them, and the tightness and a reliable functionality on the other. Typically this is achieved only by one or more expensive valve components, which are accordingly expensive, heavy and complex. Due to their complexity, they also become very susceptible to interference.

In the presentation of the 2 is an improved check valve 9 to recognize which is extremely simple, safe and reliable realized. Above the symmetry or center line of the check valve 9 , which in the representation of the 2 Denoted by A, is an open position of the check valve 9 to recognize, at which of the hydrogen H ₂ according to the illustrated flow direction, the check valve 9 flows through. The flow or the way of the flow is through a dotted line within the check valve 9 shown accordingly. Half below the center line A of the check valve 9 on the other hand shows the check valve 9 in the closed position, if the pressure applied by the hydrogen pressure is therefore insufficient to the check valve 9 to open.

With reference to the illustration with these two operating states, the check valve becomes 9 described in more detail below.

The check valve 9 consists essentially of a valve housing 10 , which consists of two housing parts 10.1 and 10.2 is trained. The inflowing hydrogen comes, as it appears from the illustration of 2 can be seen, flowed from the left side. A corresponding line is via an external thread 11 on the valve body 10 connected. The effluent hydrogen leaves the check valve 9 or its valve housing 10 in the presentation of the 2 On the right side. To connect a corresponding line element or the like is a connection with an internal thread 12 intended. This construction with an internal thread 12 on one side and an external thread 11 on the other hand, where the sides could just as well be chosen reversed, is particularly favorable, since this is the check valve 9 can not be installed in the wrong direction, which would be detrimental to its function.

In the flow direction of the hydrogen, this meets within the valve housing 10 , and here within the housing part 10.1 of the valve housing 10 , first on a filter 13 , This filter 13 consists of a supporting body 14 and a filter mat 15 which are around the supporting body 14 is arranged. The hydrogen flows through the filter mat 15 and passes through openings in the support body 14 in the interior of the supporting body 14 , The filter 13 For example, in the housing part 10.1 of the valve housing 10 be executed pressed. In the flow direction of the hydrogen following the filter 13 the hydrogen happens to be a valve seat 16 which is in a valve seat 16 having body 17 is trained. This the valve seat 16 having bodies 17 is ideally in the housing part 10.1 of the valve housing 10 Pressed and connected with this. On the rear side of the body in the flow direction of the hydrogen 17 with the valve seat 16 is a circumferential groove 18 introduced, which represents the function of a pressure activation. This increases the sealing effect between the valve seat 16 and one against the valve seat 16 pressed pistons 19 which has a streamlined body on its upstream side 20 having, which the valve body 20 the check valve 9 formed. The valve body 20 is designed streamlined, especially in the form of a "dolphin nose" to oppose the inflowing hydrogen only a minimal pressure drop in the open state. In the flow direction of the hydrogen on the valve body 20 follows an area with flow openings 21 so that the hydrogen, after being between the valve seat 16 and the valve body 20 has flowed through, into the interior of the piston 19 flow in and from there the check valve 9 can flow out. The piston 19 has on its outside in the on the flow openings 21 following part a lead 22 on, on the one hand as a stop for a spring 23 serves, and on the other hand, the piston 19 on a guide sleeve 24 leads. At the other end is the end of the piston 19 designed so that it is with the housing part 10.2 of the valve housing 10 together forms a sliding seal, which for the exact guidance of the piston 19 contributes and prevents tilting of the piston. The guide sleeve 24 has at its outer area a circumferential groove which the guide sleeve 24 in the manner of a helix, or thread surrounds, so that possibly between the guide sleeve 24 and the housing part 10.1 of the valve housing 10 accumulating gas can flow out. In addition, in the area of the guide sleeve 24 an attack 25 formed, which for example in the manner of a snap ring in a groove of the guide sleeve 24 can be used. This stop 25 limits the force with which the spring 23 the valve body 20 against the valve seat 16 pressed.

In this construction, it is now crucial that the two screwed together housing parts 10.1 and 10.2 of the valve housing 10 be reliably and reliably sealed against each other, in such a way that a high tightness is guaranteed, no matter what temperatures the check valve 9 is exposed. At least in the usual temperature ranges of -50 ° C to + 100 ° C for vehicles, the tightness must be guaranteed in any case. To achieve this is between the housing parts 10.1 and 10.2 of the valve housing 10 a metallic seal 28 realized. The housing part 10.1 the valve housing points to its external thread 11 facing away from a spherical or semicircular supernatant in cross-section 26 on. This acts with a conical or trapezoidal groove 27 of the second housing part 10.2 together. These two parts then together form the integrated metallic seal 28 which ensures a safe and reliable seal in any case. By the immediate integration of the for the metallic seal 28 necessary parts in the respective housing parts 10.1 . 10.2 of the valve housing 10 In addition, a simple and reliable installation is ensured because the two housing parts 10.1 and 10.2 of the valve housing 10 only need to be screwed against each other. For this are in the external realm 6 each key surfaces indicated and by the reference numeral 29 characterized. Typically, the suit is made with a predetermined torque, so that the seal is guaranteed in any case safely and reliably.

In particular, in hydrogen or hydrogen high-pressure systems, it is now so that the tightness has a very high importance. In order to easily verify a reliable seal, it is therefore in the check valve 9 provided that an area between the screwed together, and typically connected via a screw thread threads 30 respectively. 31 the housing parts 10.1 and 10.2 and the metallic seal 28 the housing parts 10.1 and 10.2 a connection hole 32 is arranged, which could also be referred to as leakage detection hole. This connection hole 32 connects the part between the threads 30 . 31 and the metallic seal 28 with the environment. In the area of this connection hole 32 For example, it would be very easy to detect a hydrogen leak by means of a manually operated leakage meter with a hydrogen probe. To prevent the ingress of dirt and moisture into the area of the connecting hole 32 safe and reliable to prevent is in the second housing part 10.2 of the valve housing 10 a groove 33 arranged, in which a sealing ring 34 is placed with bias. The sealing ring 34 So it is inserted in the groove under bias and thus seals the connection hole 32 , which opens in the groove, from. In the case of a hydrogen leak, the hydrogen can on the one hand by a certain overpressure inside the area between the seal 28 and the thread 30 . 31 flow off and the sealing ring 34 Raise slightly. In addition, can be for the sealing ring 34 use a suitable material, for example a silicone rubber. Such is highly elastic, even at very low ambient temperatures. He thus provides on the one hand a good seal of the connection bore 32 safe against water and dirt. On the other hand, it is very permeable to hydrogen, at least at higher temperatures, so that any hydrogen leaks in any case, the sealing ring 34 happen and so in the area of the connection opening 32 become recognizable. This will increase the safety of the check valve 9 increased again.

The structure of the non-return valve described by way of example 9 may, as already mentioned, at one or more locations of the hydrogen system within the vehicle 1 be used and would replace at this point a conventional or according to the prior art much more complex and expensive check valve.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The 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

• DE 102011121467 B4 [0003]
• JP 2009-145120 A [0004]
• US 2001/0266472 A1 [0005]

Claims (11)

Check valve ( 9 ) for high-pressure gas applications, with a first and a second housing part ( 10.1 . 10.2 ), which together a valve housing ( 10 ), with a valve seat ( 16 ) in the valve housing ( 10 ) and one in the valve housing ( 10 ) against the force of a spring ( 23 ) movable valve body ( 20 ), characterized in that between the two housing parts ( 10.1 . 10.2 ) a metallic seal ( 28 ) is provided. Check valve ( 9 ) according to claim 1, characterized in that the metallic seal ( 28 ) by a one-piece with one of the housing parts ( 10.2 ) formed circumferential conical groove ( 27 ) on the one hand and one in one piece with the other housing part ( 10.1 ) circumferential spherical surface section ( 26 ) on the other hand. Check valve ( 9 ) according to claim 1 or 2, characterized in that the valve seat ( 16 ) on one in one of the housing parts ( 10.1 ) pressed body ( 17 ) is trained. Check valve ( 9 ) according to claim 3, characterized in that a circumferential groove ( 18 ) on the side facing away in the flow direction of the gas side of the valve seat ( 16 ) having body ( 17 ) is introduced. Check valve ( 9 ) according to one of claims 1 to 4, characterized in that the valve body ( 20 ) as part of a piston ( 19 ), wherein the valve body ( 20 ) is streamlined in the direction of the inflowing gas. Check valve ( 9 ) according to claim 5, characterized in that the piston ( 19 ) between the valve body ( 20 ) and one the spring ( 23 ) leading section flow openings ( 21 ) having. Check valve ( 9 ) according to claim 5 or 6, characterized in that the piston ( 19 ) in the flow direction of the inflowing gas after the valve body ( 20 ) and optionally the flow openings ( 21 ) a lead ( 22 ) as a stop for the spring ( 23 ) and as the first guide for the piston ( 19 ), and that the piston ( 19 ) at its other end in the manner of a sliding seal in the valve housing ( 10 ) is guided. Check valve ( 9 ) according to one of claims 1 to 7, characterized in that the valve housing ( 10 ) on its first side an external thread ( 11 ) and on its other side an internal thread ( 12 ) as a connection. Check valve ( 9 ) according to one of claims 1 to 8, characterized in that in one of the housing parts ( 10.1 . 10.2 ) on the side of the metallic gasket facing away from the gas ( 28 ) a connection hole ( 32 ) is formed to the environment. Check valve ( 9 ) according to claim 9, characterized in that the connecting bore ( 32 ) in a to the valve housing ( 10 ) circumferential groove ( 33 ) ends, in which a sealing ring ( 34 ) is inserted under bias. Use of the check valve ( 9 ) according to one of claims 1 to 10, in a high-pressure hydrogen system in which the hydrogen is stored at a nominal pressure of more than 50 MPa, in particular in a vehicle ( 1 ).

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