Valve assembly for a fuel gas tank, fuel gas tank

Abstract

The invention relates to a valve assembly (1) for a fuel gas tank (2), comprising a valve block (3) with a bore (4) in which a controllable shut-off valve (5) and a check valve (6) are arranged in series, wherein the shut-off valve (5) and the check valve (6) open in opposite directions and wherein the check valve (6) has a valve element (7) axially displaceably received and guided in the bore (4) for opening and closing an outlet opening (8) of the shut-off valve (5). According to the invention, the valve element (7) has at least one longitudinal groove (9) and / or flattening on its outer circumference to form a first flow path (S1) and an axial bore (10) to form a second flow path (S2), wherein the axial bore (10) is closed by a diaphragm (11) that is permeable to gases and impermeable to liquids and solids. The invention further relates to a fuel gas tank (2) with a valve assembly (1) according to the invention.

Description

[0001] The invention relates to a valve assembly for a fuel gas tank having the features of the preamble of claim 1. Furthermore, the invention relates to a fuel gas tank with a valve assembly according to the invention. The fuel gas can be, in particular, hydrogen or natural gas, which is stored under pressure in the fuel gas tank.

[0002] The preferred field of application of the invention is fuel cell and / or gas vehicles that are powered by a fuel gas. State of the art

[0003] Mobile fuel gas tank systems are known, comprising at least one fuel gas tank for storing fuel gas, for example, hydrogen or natural gas. The fuel gas tank is typically designed as a high-pressure tank. Tank valves are typically screwed onto these tanks, via which both the refueling and the withdrawal of fuel gas are controlled. Therefore, two gas paths are formed within the tank valve: a refueling path and a withdrawal path. The tank valve can have a separate high-pressure connection for each path or a shared high-pressure connection. In the latter case, the two paths are interconnected using a valve so that, depending on the switching state, the refueling path or the withdrawal path is connected to the high-pressure connection.

[0004] When refueling a fuel gas tank, the pressure in the fuel gas tank increases with increasing filling, resulting in an increased pneumatic closing force acting on a shut-off valve located in the withdrawal path. This increases the load on the shut-off valve in the area of ​​its valve seat, which can lead to increased wear and ultimately to the shut-off valve's failure.

[0005] Another problem that can occur during refueling is the inadvertent opening of the shut-off valve, resulting in reverse flow and fuel gas entering the fuel gas tank via the withdrawal path. This is undesirable for several reasons. Firstly, to ensure even temperature distribution in the fuel gas tank, filling should only take place via the refueling path. For this purpose, the refueling path ends in a filler pipe that reaches deep into the fuel gas tank. Secondly, there is a risk that water could enter the shut-off valve along with the fuel gas. This can freeze and cause damage to the valve. For this reason, a check valve is usually integrated into the withdrawal path of a tank valve to prevent fuel gas and / or water from entering the shut-off valve during refueling.However, when fuel gas is withdrawn from the fuel gas tank, the spring force of a closing spring of the check valve leads to a throttling of the withdrawal quantity.

[0006] The present invention is concerned with the object of providing a valve assembly for a fuel gas tank that does not have the aforementioned disadvantages. In particular, damage due to excessive seat loading and / or water ingress at a shut-off valve integrated into a discharge path is to be prevented.

[0007] To achieve this objective, the valve assembly having the features of claim 1 is proposed. Advantageous further developments of the invention are set forth in the subclaims. Furthermore, a fuel gas tank having a valve assembly according to the invention is specified. Disclosure of the invention

[0008] The valve assembly proposed for a fuel gas tank comprises a valve block with a bore in which a controllable shut-off valve and a check valve are arranged in series. The shut-off valve and the check valve open in opposite directions, and the check valve has a valve element axially displaceably received and guided in the bore for opening and closing an outlet opening of the shut-off valve. According to the invention, the valve element has at least one longitudinal groove and / or flattened portion on its outer circumference to form a first flow path and an axial bore to form a second flow path. The axial bore is closed by a membrane that is permeable to gases and impermeable to liquids and solids.

[0009] When closed, the check valve closes the outlet opening of the shut-off valve, thereby preventing fuel gas and thus water from entering the shut-off valve. The opening and closing of the check valve is pressure-controlled, i.e., via the pressure conditions present at the valve element or the resulting pressure difference. The check valve therefore does not have to be opened against the spring force of a closing spring, so that the amount of gas flowing out through the shut-off valve is not throttled. The gas then flows out via the first flow path, which is formed by at least one longitudinal groove and / or flattened area on the outer circumference. The second flow path serves a different purpose, namely to at least approximately equalize the pressures present on both sides of the valve element when the check valve is closed.In this way, the seat load of the shut-off valve can be reduced at the same time when the tank pressure increases when refueling the fuel gas tank.

[0010] Pressure equalization is achieved by the fact that the membrane sealing the second flow path is only permeable to gas. This means that fuel gas, but not water, passes through the second flow path into the area of ​​the shut-off valve's outlet opening. The protective effect of the check valve is thus still ensured.

[0011] In order to simultaneously reduce the seat load of the shut-off valve through the pressure equalization achieved, it is further proposed that the outlet opening of the shut-off valve be formed by a component bore, which at the other end forms a valve seat of the shut-off valve. The pressure rising in the component bore then creates a counterpressure as the tank pressure increases, leading to the desired relief.

[0012] According to a preferred embodiment of the invention, the diaphragm is arranged on an annular collar and / or collar radially defining the axial bore and is firmly connected to the valve element. Ideally, the annular collar and / or collar are arranged downstream of the diaphragm in the main flow direction of the fuel gas during refueling through the axial bore, so that the flow forces press the diaphragm against the annular collar and / or collar. This can stabilize the diaphragm.

[0013] Furthermore, the membrane is preferably arranged so that it is set back from a front sealing surface of the valve element. This set-back arrangement optimally protects the membrane from damage.

[0014] Furthermore, it is proposed that the valve element form an interior space connected to the axial bore, which is open toward the at least one longitudinal groove and / or flattened portion, so that the interior space connects the two flow paths. The two flow paths can be merged in this way.

[0015] In a further development of the invention, it is proposed that the membrane be accommodated in the interior. In this arrangement, the membrane is particularly well protected.

[0016] Furthermore, the valve element is preferably designed in several parts to form the interior. If a membrane is accommodated in the interior, this can facilitate the assembly of the membrane.

[0017] Advantageously, a throttle is integrated into the axial bore. The throttle limits the flow through the second flow path toward the outlet opening of the shut-off valve, resulting in pressure equalization but not complete pressure equalization, as otherwise the shut-off valve could open unintentionally. Should this occur, the amount of gas flowing through the shut-off valve into the fuel gas tank is low due to the limited flow. The limited flow caused by the throttle also creates a pressure drop, which reduces the pressure difference across the diaphragm and thus protects the diaphragm from damage due to overload.

[0018] Preferably, the bore formed in the valve block forms a withdrawal path that leads in the withdrawal direction via the shut-off valve and then via the check valve. In this embodiment of the valve assembly, the advantages of the invention become particularly apparent, as the problems described above are eliminated.

[0019] Furthermore, a further bore forming a refueling path preferably branches off from the bore downstream of the check valve in the withdrawal direction. The valve assembly can therefore be, in particular, a tank valve for a fuel gas tank, through which fuel gas can be withdrawn from the fuel gas tank and the fuel gas tank can be filled with fuel gas. When refueling the fuel gas tank, the check valve prevents water from entering the shut-off valve.

[0020] Since the preferred field of application of a valve assembly according to the invention is a fuel gas tank, a fuel gas tank with a valve assembly according to the invention is further proposed.

[0021] Preferred embodiments of the invention are explained in more detail below with reference to the accompanying drawings. These show: Fig. 1 a schematic longitudinal section through a first valve assembly according to the invention for a fuel gas tank during a refueling process, Fig. 2 a schematic longitudinal section through the valve assembly of the Fig. 1 during a withdrawal process, Fig. 3 a schematic longitudinal section through a second valve assembly according to the invention for a fuel gas tank during a refueling process and Fig. 4 a schematic representation of a fuel gas tank with a valve assembly. Detailed description of the drawings

[0022] The Fig. 1 and Fig. Figure 2 shows a first valve assembly 1 according to the invention, which is only partially shown in both figures. The section shows the valve assembly 1 in the area of ​​a controllable shut-off valve 5 and a check valve 6, which are integrated into a valve block 3 of the valve assembly 1. For this purpose, a bore 4 is formed in the valve block 3, in which the shut-off valve 5 and the check valve 6 are accommodated.

[0023] The Fig. 1 and Fig. The valve assembly 1 shown in Figure 2 can in particular - as exemplified in the Fig. 4 - into a fuel gas tank 2. A withdrawal path 19 then runs through the bore 4, from which another bore 20 branches off downstream of the check valve 6 in the withdrawal direction, through which a refueling path 21 runs. When the fuel gas tank 2 is filled with fuel gas via the refueling path 21, the check valve 6 prevents fuel gas and thus also water from entering the shut-off valve 5. The check valve 6 also offers further advantages, which are described below in connection with various embodiments.

[0024] The Fig. 1 and Fig. The check valve 6 shown in Figure 2 has a valve element 7 which is axially displaceably received and guided in the bore 4 and which is designed in several parts in the present case. It has a central closing element 7.1 and a housing 7.2 which receives the closing element 7.1 and forms an interior space 17. The valve element 7 is guided in the bore 4 via the housing 7.2 in a stroke-movable manner. The stroke of the valve element 7 is limited by a shoulder 22 formed in the bore 4. In order to allow flow around the valve element 7 during the full stroke, the housing 7.2 has at least one longitudinal groove 9. The longitudinal groove 9 thus forms a first flow path S1, via which fuel gas can be withdrawn from the fuel gas tank 2 when the shut-off valve 5 is open (see Fig. 2).

[0025] The closing element 7.1 accommodated in the housing 7.2 has an axial bore 10 for forming a second flow path S2. The axial bore 10 is covered by a membrane 11, which rests on a collar 15 of the closing element 7.1 and is firmly connected to the closing element 7.1 via the collar 15. The membrane 11 is permeable to gases and impermeable to liquids and solids. This means that the membrane 11 prevents the penetration of water and particles into the shut-off valve 5 via the second flow path S2. However, during refueling, when the pressure conditions at the valve element 7 close the check valve 6, fuel gas can flow via the second flow path S2 towards the shut-off valve 5 (see Fig. 1). This has the advantage that the pressure in a component bore 12 of the shut-off valve 5 rises, which on the one hand defines an outlet opening 8 and on the other hand a valve seat 13 of the shut-off valve 5. Since the outlet opening 8 is closed by a front-end sealing surface 16 of the valve element 7 during refueling, the pressure in the component bore 12 is trapped. However, as the fuel gas tank 2 is increasingly filled with fuel gas, the pressure in the fuel gas tank 2 rises, so that an increased pneumatic closing force acts on the shut-off valve 5. This increases the load on the shut-off valve 5 in the area of ​​the valve seat 13. By filling the component bore 12 with fuel gas via the second flow path S2, a pressure equalization can be achieved, which reduces the load and thus the wear on the valve seat 13.

[0026] Depending on the amount of fuel gas entering the component bore 12 via the second flow path S2, pressure equalization may occur, but rather pressure equalization may occur, so that the pneumatic forces acting on the shut-off valve 5 are almost balanced. This increases the risk of unintentional opening of the shut-off valve 5 during the filling of the fuel gas tank 2 with fuel gas. To counteract this, a throttle 18 is integrated into the axial bore 10 of the closing element 7.1, which limits the flow toward the component bore 12.

[0027] A further advantage of check valve 6 is that it operates solely on pressure control. This means that no spring force from a return or closing spring needs to be overcome when opening. Even small withdrawal quantities can thus be withdrawn without throttling.

[0028] The Fig. 3 shows a further preferred embodiment of a valve assembly 1 according to the invention for a fuel gas tank 2. This also has a shut-off valve 5 and a check valve 6, which are accommodated in a bore 4 of a valve block 3. Differences from the embodiment of Fig. 1 and Fig. 2, the valve assembly 1 has the design of the check valve 6.

[0029] The check valve 6 of the valve assembly 1 of the Fig. 3 has a one-piece valve element 7 with an axial bore 10 and a diaphragm 11 for closing the axial bore 10. Here, too, a throttle 18 is integrated into the axial bore 10. The diaphragm 11 is arranged upstream of the throttle 18 in the withdrawal direction on a collar 15 which is formed by an annular collar 14. When fuel gas is withdrawn from the fuel gas tank 2, the diaphragm 11 is accordingly pressed against the collar 15 so that the diaphragm 11 is stabilized by the collar 15. In the refueling direction, the throttle 18 limits the flow in the direction of the diaphragm 11 so that the load on the diaphragm 11 is reduced. Because the annular collar 14 and the collar 15 are arranged axially offset inwards relative to the end-face sealing surface 16, the diaphragm 11 is also set back relative to the sealing surface 16. In this way, the membrane 11 is protected from destruction, but can still be easily installed.Here, too, the axial bore 10 forms a second flow path S2 (not shown). The first flow path S1 (not shown) leads via a longitudinal groove 9 formed on the outer circumference of the valve element 7.

[0030] As merely exemplified in the Fig. As shown in Figure 4, a valve assembly 1 according to the invention can comprise further components in addition to the shut-off valve 5 and the check valve 6. These can, in particular, be additional valves 23 and / or filters 24.

Claims

[1] Valve assembly (1) for a fuel gas tank (2), comprising a valve block (3) with a bore (4) in which a controllable shut-off valve (5) and a check valve (6) are arranged in series, wherein the shut-off valve (5) and the check valve (6) open in opposite directions and wherein the check valve (6) has a valve element (7) axially displaceably received and guided in the bore (4) for opening and closing an outlet opening (8) of the shut-off valve (5), characterized by that the valve element (7) has at least one longitudinal groove (9) and / or flattening on the outer circumference for forming a first flow path (S1) and an axial bore (10) for forming a second flow path (S2), wherein the axial bore (10) is closed by a membrane (11) which is permeable to gases and impermeable to liquids and solids. [2] Valve assembly (1) according to claim 1, characterized bythat the outlet opening (8) of the shut-off valve (5) is formed by a component bore (12) which at the other end forms a valve seat (13) of the shut-off valve (5). [3] Valve assembly (1) according to claim 1 or 2, characterized by that the membrane (11) is arranged on an annular collar (14) and / or collar (15) radially delimiting the axial bore (10) and is firmly connected to the valve element. [4] Valve assembly (1) according to one of the preceding claims, characterized by that the membrane (11) is arranged backwards relative to a front sealing surface (16) of the valve element (7). [5] Valve assembly (1) according to one of the preceding claims, characterized by that the valve element (7) forms an interior space (17) which is connected to the axial bore (10) and which is open towards the at least one longitudinal groove (9) and / or flattened portion, so that the interior space (17) connects the two flow paths (S1, S2). [6] Valve assembly (1) according to claim 5, characterized by that the membrane (11) is accommodated in the interior space (17) and / or the valve element (7) is designed in several parts to form the interior space (17). [7] Valve assembly (1) according to one of the preceding claims, characterized by that a throttle (18) is integrated into the axial bore (10). [8] Valve assembly (1) according to one of the preceding claims, characterized by that the bore (4) formed in the valve block (3) forms a removal path (19) which leads in the removal direction via the shut-off valve (5) and then via the check valve (6). [9] Valve assembly (1) according to claim 8, characterized by that in the withdrawal direction downstream of the check valve (6) a further bore (20) forming a refueling path (21) branches off from the bore (4). [10] Fuel gas tank (2) with a valve assembly (1) according to one of the preceding claims.

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