Valve assembly for a fuel gas tank, fuel gas tank comprising a valve assembly

Abstract

The invention relates to a valve assembly (1) for a fuel gas tank (2), comprising a base body (3) in which an extraction path (4) with an integrated shut-off valve (6) for extracting fuel gas from the fuel gas tank (2) and a refuelling path (5) with an integrated non-return valve (7) for refuelling the fuel gas tank (2) with fuel gas are formed, wherein the extraction path (4) and the refuelling path (5) are brought together within the base body (3) in a path (9) which opens into a common gas connection (8). According to the invention, a pressure equalisation path (10) branches off from this path (9) and opens into the removal path (4) upstream of the shut-off valve (6) in the removal direction, whereby a non-return valve (12) is integrated into the pressure equalisation path (10), which blocks in the removal direction. The invention further relates to a fuel gas tank (2) having the claimed valve assembly (1).

Description

[0001] Description

[0002] Valve assembly for a fuel gas tank, fuel gas tank with valve assembly

[0003] The invention relates to a valve assembly for a fuel gas tank. Furthermore, the invention relates to a fuel gas tank with a valve assembly according to the invention. The fuel gas can, in particular, be hydrogen or natural gas, which is stored under pressure in a fuel gas tank.

[0004] The preferred field of application of the invention is fuel cell and / or gas vehicles that are powered by a fuel gas.

[0005] State of the art

[0006] Mobile fuel gas tank systems are known, consisting of at least one fuel gas tank for storing fuel gas, such as hydrogen or natural gas. The fuel gas tank is typically designed as a high-pressure tank, particularly a high-pressure gas cylinder. A high-pressure tank always requires a shut-off valve to seal the tank tightly when the vehicle is not in use. For safety reasons, the shut-off valve is usually designed as a normally closed valve.

[0007] The shut-off valve is usually integrated into a valve assembly that enables both the withdrawal of fuel gas from the fuel gas tank and the refueling of the fuel gas tank with fuel gas. For this purpose, the valve assembly has a base body in which a withdrawal path and a refueling path are formed. A controllable shut-off valve is integrated into the withdrawal path and a check valve is integrated into the refueling path. The check valve prevents fuel gas from escaping from the fuel gas tank via the refueling path. A further check valve can be arranged in the withdrawal path so that the flow direction in both paths is determined via the check valves. DE 10 2016 008 443 A1 discloses, by way of example, a tank valve for mounting on a compressed gas container. The tank valve has a base body with a gas connection via which the compressed gas container can be refueled on the one hand and gas can be withdrawn from the compressed gas container on the other.Within the base body, the gas connection is divided into a refueling line and a withdrawal line, with a withdrawal valve located in the withdrawal line. A check valve connected in series with the withdrawal valve blocks the flow in the opposite direction to the intended direction when gas is withdrawn. The check valve thus prevents gas from flowing into the compressed gas cylinder via the withdrawal line during refueling. Another check valve is integrated into the refueling line, which opens in the refueling direction and closes in the withdrawal direction.

[0008] The present invention is concerned with the object of providing a valve assembly with an integrated shut-off valve for withdrawing fuel gas from a fuel gas tank, in which unintentional opening of the shut-off valve is reliably prevented. Furthermore, the shut-off valve of the valve assembly should be able to be used for refueling the fuel gas tank.

[0009] 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.

[0010] Disclosure of the invention

[0011] The valve assembly proposed for a fuel gas tank comprises a base body in which a withdrawal path with an integrated shut-off valve for withdrawing fuel gas from the fuel gas tank and a refueling path with an integrated check valve for refueling the fuel gas tank with fuel gas are formed. The withdrawal path and the refueling path are combined within the base body in a path that opens into a common gas connection. According to the invention, a pressure equalization path branches off from this path or from an end face of the common gas connection, which opens into the withdrawal path upstream of the shut-off valve in the withdrawal direction. A check valve is integrated into the pressure equalization path, which blocks in the withdrawal direction.

[0012] The pressure equalization path with integrated check valve ensures that - regardless of the pressure in the fuel gas tank and regardless of the pressure in the area of ​​the gas connection - the higher of the two pressures is always present on the inflow side of the shut-off valve. On the outflow side of the shut-off valve, on the other hand, the pressure prevailing in the area of ​​the gas connection is always present. The pressure on the inflow side is therefore always greater than or equal to the pressure on the outflow side. This means that there is never a differential pressure at the shut-off valve that would cause the shut-off valve to open unintentionally. This ensures that flow through the shut-off valve only in the direction of withdrawal and not in the opposite direction. When filling the fuel gas tank with fuel gas, it is therefore ensured that no fuel gas contaminated with water gets into the shut-off valve, freezes at low outside temperatures and blocks the shut-off valve.

[0013] Another advantage is that only a small gas flow flows through the pressure equalization path for a short time to achieve the desired pressure equalization. This allows the pressure equalization path and its integrated check valve to be designed for low flow rates. The additional path and the additional check valve therefore require little installation space.

[0014] Preferably, a check valve is integrated into the extraction path upstream of the inlet pressure equalization path in the extraction direction. This check valve opens in the extraction direction and closes in the opposite direction. The inflow side of the shut-off valve is thus protected by two check valves. The check valve integrated into the pressure equalization path prevents fuel gas from escaping from the fuel gas tank—similar to the check valve in the refueling path. The check valve integrated into the extraction path prevents fuel gas from flowing back from the inflow side of the shut-off valve into the fuel gas tank, thus ensuring that no continuous gas flow can occur via the pressure equalization path.

[0015] According to a preferred embodiment of the invention, the base body has a connecting section for connection to the fuel gas tank. The connecting section can have an external thread for screwing the valve assembly into the fuel gas tank, in particular into a bottle neck of the fuel gas tank. This simplifies the installation of the valve assembly on the fuel gas tank.

[0016] Furthermore, it is proposed that the extraction path and the refueling path be connected to a storage volume of the fuel gas tank via a common path. In this case, the extraction path and the refueling path are each combined into a single path not only in the area of ​​the gas connection, but also on the side of the fuel gas tank. Thus, only one path leads into the fuel gas tank. As a result, the connecting section for connecting the valve assembly to the fuel gas tank can be smaller, which is particularly advantageous if the valve assembly is to be inserted into a bottle neck of the fuel gas tank.

[0017] If sufficient space is available, the extraction path and the refueling path can also be designed as separate paths in the connecting section of the valve assembly. This eliminates the need for a bore intersection. In this case, the extraction path and the refueling path lead into the fuel gas tank as separate paths.

[0018] If sufficient space is available, the extraction path and the refueling path can also be designed as separate paths in the shared gas connection. This eliminates the need for further borehole intersection. In this case, the extraction path and the refueling path can also lead to an external gas connection line as separate paths.

[0019] In a further development of the invention, it is proposed that the check valve integrated into the extraction path and the check valve integrated into the pressure equalization path be combined into a single component. This measure allows the valve assembly to be simplified and, at the same time, made more compact.

[0020] For this purpose, the component can have two valve closing elements, between which a spring is arranged, by which each valve closing element is pretensioned towards a valve seat. The component can be connected to the inflow side of the shut-off valve via the space between the two valve closing elements that accommodates the spring. The two valve closing elements can be designed as balls that interact with conical valve seats. The balls do not require radial guidance, as they align themselves with respect to the conical valve seats. Thus, when the valve is opened, the balls release a sufficient flow cross-section to connect the inflow side of the shut-off valve to the fuel gas tank via the extraction path or to the gas connection via the pressure equalization path.

[0021] Alternatively, the component can have a one-piece valve closing element that can move back and forth between two valve seats, comprising a circumferential groove and at least one longitudinal groove. The component can be connected to the inflow side of the shut-off valve via the circumferential groove. The at least one longitudinal groove connects the circumferential groove to the gas volumes at the valve seats. Depending on the pressure conditions outside the two valve seats, the valve element is moved purely pneumatically into one or the other end position, so that one valve seat is open and the other closed. Both valve seats are never open or closed at the same time. The opening and closing of the check valves can therefore be achieved purely pneumatically. This means that a spring is unnecessary.

[0022] The shut-off valve is preferably electrically controlled and / or designed as a normally closed valve. As an electrically controlled valve, the shut-off valve can be designed to be particularly compact and robust. Furthermore, the shut-off valve can be actively opened to remove fuel gas from the fuel gas tank. In the normally closed valve design, it meets the safety requirements for a fuel gas tank.

[0023] Furthermore, it is proposed that the common gas connection be designed as a connecting piece, preferably as a connecting piece with an external thread. The connecting piece facilitates the connection of an external gas line, through which fuel gas can be extracted from the fuel gas tank and supplied to the fuel gas tank during refueling. If the connecting piece has an external thread, the external gas line can be screwed onto the connecting piece, creating a high-pressure-resistant connection between the gas line and the valve assembly via the screw connection.

[0024] The further proposed fuel gas tank is characterized by having a valve assembly according to the invention. The valve assembly is preferably inserted into the fuel gas tank in sections, so that the common gas connection is accessible from the outside. Since the extraction path and the refueling path are combined and lead as a single path into the common gas connection of the valve assembly, only one gas line needs to be connected for extracting fuel gas and for refueling the fuel gas tank with fuel gas.

[0025] Preferred embodiments of the invention are explained in more detail below with reference to the accompanying drawings. These show:

[0026] Fig. 1 is a schematic representation of a valve assembly according to the invention inserted into a fuel gas tank with arrows to show the gas flow directions when removing fuel gas from the fuel gas tank, when filling the fuel gas tank with fuel gas and during pressure equalization,

[0027] Fig. 2 is a schematic representation of a further valve assembly according to the invention inserted into a fuel gas tank with arrows to show the gas flow directions when removing fuel gas from the fuel gas tank, when filling the fuel gas tank with fuel gas and during pressure equalization,

[0028] Fig. 3 shows a longitudinal section through two check valves opening in opposite directions, which are combined to form a component with two valve closing elements, two valve seats and a spring,

[0029] Fig. 4 shows a longitudinal section through two check valves opening in opposite directions, which are combined to form a component with a one-piece valve closing element,

[0030] Fig. 5 shows a cross section through the component of Figure 4 and Fig. 6 shows a further longitudinal section through the component of Figure 4, but in a different switching position.

[0031] Detailed description of the drawings

[0032] The valve assembly 1 according to the invention shown in Figure 1 serves to remove fuel gas from a fuel gas tank 2 and to fill the fuel gas tank 2 with fuel gas, in particular with hydrogen or with natural gas.

[0033] The illustrated valve assembly 1 comprises a base body 3 with a connecting portion 13, via which the valve assembly 1 is connected to the fuel gas tank 2. At the other end, the base body 3 forms a gas connection 8 for connecting an external gas line (not shown).

[0034] The base body 3 contains a withdrawal path 4 for withdrawing fuel gas from the fuel gas tank 2 and a refueling path 5 for refueling the fuel gas tank 2. Integrated into the withdrawal path 4 is a shut-off valve 6, which is electrically controllable and designed as a normally closed valve. Upstream of the shut-off valve 6 in the withdrawal direction (arrow 23), i.e., on the inflow side of the shut-off valve 6, is a check valve 11 that opens in the withdrawal direction and closes in the opposite direction. Integrated into the refueling path 5 is a further check valve 7 that opens in the refueling direction (arrow 24) and closes in the opposite direction. On the downstream side of the shut-off valve 6, the withdrawal path 4 and the refueling path 5 are combined to form a path 9, which opens into the gas connection 8.A pressure relief path 10 branches off from this path 9, which opens into the extraction path 4 upstream of the shut-off valve 6 in the extraction direction, specifically downstream of the check valve 11 integrated into the extraction path 4. The pressure equalization path 10 thus connects the downstream side with the inflow side of the shut-off valve 6. To prevent fuel gas from flowing out of the fuel gas tank 2 via the pressure equalization path 10, a further check valve 12 is integrated into the pressure equalization path 10, which blocks in the extraction direction. In the opposite direction (arrow 25), however, the check valve 12 allows pressure equalization between the downstream side and the inflow side of the shut-off valve 6. This ensures that the pressure pi. non the inflow side of the shut-off valve 6 never falls below the pressure P2 on the outflow side. The pressure conditions at the shut-off valve 6 thus ensure that the shut-off valve 6 cannot open accidentally. In particular, when filling the fuel gas tank 2 with fuel gas, the pressure P2 on the outflow side cannot exceed the pressure pi n on the inflow side of the shut-off valve 6.

[0035] In the area of ​​the connecting section 13, the extraction path 4 and the refueling path 5 are merged into a single path 14, so that only this single path 14 leads into the fuel gas tank 2. In this case, the connecting section 13 can be dimensioned very small.

[0036] To avoid further bore intersection, the extraction path 4 and the refueling path 5 can also be connected as separate paths to the storage volume of the fuel gas tank 2. This embodiment is shown as an example in Figure 2. Otherwise, the embodiment of Figure 2 corresponds to that of Figure 1.

[0037] To avoid further bore intersection, the pressure equalization path 10 can also not open into path 9 within the base body 3, but instead be routed directly to the end face of the base body 3 or the gas connection 8, so that it opens directly into a connected external gas line. This embodiment is not shown separately in the figures, as it can be derived from Figures 1 and 2.

[0038] The check valves 11, 12, which open in opposite directions and are shown in Figures 1 and 2, can be combined into a single component 15 to save installation space. Possible embodiments of such a component 15 are shown as examples in Figures 3 to 6.

[0039] A first preferred embodiment of a component 15 is shown in Figure 3. Here, the component 15 has two valve closing elements 18.1, 18.2, wherein each valve closing element 18.1, 18.2 is prestressed in the direction of a valve seat 16, 17 by a common spring 19 arranged between the two valve closing elements 18.1, 18.2. Each valve closing element 18.1, 18.2 is thus assigned a valve seat 16, 17. The spring 19 is accommodated in a valve chamber 22, which connects the component 15 to the inflow side of the shut-off valve 6. When fuel gas is extracted from the fuel gas tank 2, the check valve 11 opens with the valve closing element 18.1 against the spring force of the spring 19, while the valve closing element 18.2 is pressed against its valve seat 17, thus closing the check valve 12. When pressure equalization occurs via the pressure equalization path 10, the check valve 12 opens with the valve closing element 18.2 against the spring force of the spring 19, while the valve closing element 18.1 is pressed against its valve seat 16 and thus closes the check valve 11.

[0040] Another preferred embodiment of a component 15 is shown in Figures 4 to 6. Here, the valve closing element 18 is constructed in one piece and is controlled solely by pressure, i.e., pneumatically, so that a spring 19 is unnecessary. For this purpose, the valve closing element 18 has a circumferential groove 20, via which the valve chamber 22 is connected to the inflow side of the shut-off valve 6.

[0041] Since the valve closing element 18 is guided radially, it also has at least one longitudinal groove 21 on each side of the circumferential groove 20, which opens into the circumferential groove 20 and serves as a gas flow channel (see Figure 5). When the check valve 11 is open, gas flows from there via the at least one longitudinal groove 21 between the circumferential groove 20 and the end of the guide of the valve closing element 18 facing the valve seat 16 to the valve chamber 22. When the check valve 12 or valve seat 17 is open, the gas flows from there via the at least one longitudinal groove 21 between the circumferential groove 20 and the end of the guide of the valve closing element 18 facing the valve seat 17 to the valve chamber 22.

[0042] Figure 4 shows the valve closing element 18 in a switching position, which it assumes when P2 > pi. Pressure equalization can then be achieved via the open check valve 12, preventing unintentional opening of the shut-off valve 6. The check valve 11 is closed in this switching position.

[0043] Figure 6 shows the valve closing element 18 in a switching position that it assumes when P2 < pi and the shut-off valve 6 is actively opened. Fuel gas can then be drawn from the fuel gas tank 2 via the open check valve 11 and fed to the gas connection 8 via the open shut-off valve 6. The check valve 12 is closed in this switching position.

[0044] A valve assembly according to the invention may comprise additional valves and / or components in addition to the valves shown. For example, a manual shut-off and / or blow-off valve, a thermal and / or pressure-controlled safety valve, and a temperature and / or pressure sensor may be integrated into the valve assembly.

Claims

Claims 1. Valve assembly (1) for a fuel gas tank (2), comprising a base body (3) in which a withdrawal path (4) with an integrated shut-off valve (6) for withdrawing fuel gas from the fuel gas tank (2) and a refueling path (5) with an integrated check valve (7) for refueling the fuel gas tank (2) with fuel gas are formed, wherein the withdrawal path (4) and the refueling path (5) are combined within the base body (3) in a path (9) which opens into a common gas connection (8), characterized in that a pressure equalization path (10) branches off from this path (9) or from an end face of the gas connection (8), which opens into the withdrawal path (4) upstream of the shut-off valve (6) in the withdrawal direction, wherein a check valve (12) which blocks in the withdrawal direction is integrated into the pressure equalization path (10).

2. Valve assembly (1) according to claim 1, characterized in that in the removal direction upstream of the incoming pressure equalization path (10) a check valve (11) is integrated into the removal path (4), which opens in the removal direction.

3. Valve assembly (1) according to claim 1 or 2, characterized in that the base body (3) has a connecting section (13) for connection to the fuel gas tank (2).

4. Valve assembly (1) according to one of the preceding claims, characterized in that the removal path (4) and the refueling path (5) are connected to a storage volume of the fuel gas tank (2) via a common path (14).

5. Valve assembly (1) according to one of the preceding claims, characterized in that the check valve (11) integrated into the extraction path (4) and the check valve (12) integrated into the pressure compensation path (10) are combined to form one component (15).

6. Valve assembly (1) according to claim 5, characterized in that the component (15) has two valve closing elements (18.1, 18.2), between which a spring (19) is arranged, by means of which each valve closing element (18.1, 18.2) is prestressed in the direction of a valve seat (16, 17).

7. Valve assembly (1) according to claim 5, characterized in that the component (15) has a one-piece valve closing element (18) which can be moved back and forth between two valve seats (16, 17) and has a circumferential groove (20) and at least one longitudinal groove (21).

8. Valve assembly (1) according to one of the preceding claims, characterized in that the shut-off valve (6) is electrically controllable and / or is designed as a normally closed valve.

9. Valve assembly (1) according to one of the preceding claims, characterized in that the common gas connection (8) is designed as a connection piece, preferably as a connection piece with an external thread.

10. Fuel gas tank (2) with a valve assembly (1) according to one of the preceding claims, wherein the valve assembly (1) is preferably inserted in sections into the fuel gas tank (2) so that the common gas connection (8) is accessible from the outside.

Images