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] 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 be, in particular, hydrogen or natural gas, which is stored under pressure in a fuel gas tank.

[0002] The preferred application area 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 to have 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, especially 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 operation. For safety reasons, the shut-off valve is usually designed as a normally closed (NC) valve.

[0004] The shut-off valve is typically integrated into a valve assembly that allows both the withdrawal of fuel gas from the fuel gas tank and the refueling of the fuel gas tank with fuel gas. This valve assembly comprises a base body containing a withdrawal path and a refueling path. 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 may be located in the withdrawal path, thus defining the flow direction in both paths.

[0005] German patent application DE 10 2016 008 443 A1 discloses an exemplary tank valve for mounting on a pressurized gas cylinder. This valve comprises a base body with a gas connection through which the pressurized gas cylinder can be both filled and gas can be withdrawn. Within the base body, the gas connection splits into a filling 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 of gas against the intended flow direction during withdrawal. The check valve thus prevents gas from flowing into the pressurized gas cylinder via the withdrawal line during filling. A further check valve is integrated into the filling line, which opens in the filling direction and closes in the withdrawal direction.

[0006] DE 10 2016 008 442 A1 discloses a tank valve for a pressurized gas container with a common gas connection, which internally divides into a refueling path and a withdrawal path with a shut-off valve.

[0007] The present invention addresses the objective of providing a valve assembly with an integrated shut-off valve for withdrawing fuel gas from a fuel gas tank, whereby unintentional opening of the shut-off valve is reliably prevented. Furthermore, the shut-off valve of the valve assembly should be usable for refueling the fuel gas tank.

[0008] To solve the problem, a valve assembly with the features of claim 1 is proposed. Advantageous embodiments of the invention are described in the dependent claims. Furthermore, a fuel gas tank with a valve assembly according to the invention is described. Disclosure of the invention

[0009] The proposed valve assembly 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 into a single path that leads to 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 and leads 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 flow in the withdrawal direction.

[0010] The pressure equalization path with integrated check valve ensures that – regardless of the pressure in the fuel gas tank or the pressure at the gas connection – the higher of the two pressures is always present on the inlet side of the shut-off valve. On the outlet side of the shut-off valve, the pressure is always that prevailing at the gas connection. The pressure on the inlet side is therefore always greater than or equal to the pressure on the outlet side. This means that there is never a pressure differential at the shut-off valve that would cause it to open unintentionally. This ensures that the shut-off valve is only open in the direction of withdrawal and not in the reverse direction. When refueling the fuel gas tank, this prevents water-contaminated fuel gas from entering the shut-off valve, freezing at low ambient temperatures, and blocking it.

[0011] A further advantage is that only a small gas flow, and only briefly, passes through the pressure equalization path to achieve the desired pressure equalization. This allows the pressure equalization path and its integrated check valve to be designed for low flow rates. Consequently, the additional path and check valve require very little installation space.

[0012] Preferably, a check valve is integrated into the withdrawal path upstream of the incoming pressure equalization path in the withdrawal direction. This check valve opens in the withdrawal direction and closes in the opposite direction. The inlet 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 the fuel gas tank, analogous to the check valve in the refueling path. The check valve integrated into the withdrawal path also prevents fuel gas from flowing back from the inlet side of the shut-off valve into the fuel gas tank, thereby ensuring that no continuous gas flow can occur via the pressure equalization path.

[0013] 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 neck of the fuel gas tank. This simplifies the installation of the valve assembly on the fuel gas tank.

[0014] Furthermore, it is proposed that the withdrawal path and the refueling path be connected to a storage volume of the fuel gas tank via a common path. In this case, the withdrawal path and the refueling path are merged into a single path not only at the gas connection but also on the fuel gas tank side. Thus, only one path leads into the fuel gas tank. Consequently, the connecting section for linking the valve assembly to the fuel gas tank can be made smaller, which is particularly advantageous if the valve assembly is to be installed in a bottleneck of the fuel gas tank.

[0015] Provided sufficient space is available, the extraction path and the refueling path can also be implemented as separate paths within 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 open into the fuel gas tank as separate paths.

[0016] Provided sufficient space is available, the extraction path and the refueling path within the shared gas connection can be implemented as separate paths. This eliminates the need for an additional borehole intersection. In this case, the extraction path and the refueling path can also terminate as separate paths in an external gas connection line.

[0017] 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 made more compact.

[0018] The component can have two valve closing elements, between which a spring is arranged, biasing each valve closing element towards a valve seat. The component can be connected to the supply side of the shut-off valve via the space between the two valve closing elements, which accommodates the spring. The two valve closing elements can be designed as spheres that interact with conical valve seats. The spheres do not require radial guidance, as they self-align with the conical valve seats. Thus, when the valve opens, the spheres provide a sufficient flow cross-section to connect the supply 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.

[0019] Alternatively, the component can be a one-piece, reciprocating valve closing element with a circumferential groove and at least one longitudinal groove. The circumferential groove allows the component to be connected to the inlet side of the shut-off valve. 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 pneumatically to either one end position or the other, so that one valve seat is open and the other closed. Both valve seats are never open or closed simultaneously. The opening and closing of the check valves can therefore be achieved purely pneumatically. This means that a spring is unnecessary.

[0020] The shut-off valve is preferably electrically actuated and / or designed as a normally closed (NC) valve. As an electrically actuated valve, the shut-off valve can be made particularly compact and robust. Furthermore, the shut-off valve can be actively opened to draw fuel gas from the fuel gas tank. In its normally closed (NC) configuration, it meets the safety requirements for a fuel gas tank.

[0021] Furthermore, it is proposed that the common gas connection be designed as a connection fitting, preferably with an external thread. This connection fitting facilitates the connection of an external gas line, allowing fuel gas to be drawn from the fuel tank and fuel gas to be supplied to the tank during refueling. If the connection fitting has an external thread, the external gas line can be screwed onto it, creating a high-pressure-resistant connection between the gas line and the valve assembly.

[0022] The proposed fuel gas tank is further characterized by the fact that it incorporates a valve assembly according to the invention. Preferably, the valve assembly is inserted section by section into the fuel gas tank, so that the common gas connection is accessible from the outside. Since the withdrawal path and the refueling path are combined and merge as a single path into the common gas connection of the valve assembly, only one gas line needs to be connected for both the withdrawal of fuel gas and the refueling of the fuel gas tank.

[0023] Preferred embodiments of the invention are explained in more detail below with reference to the accompanying drawings. These show: Fig. 1a schematic representation of a valve assembly according to the invention inserted into a fuel gas tank with arrows to show the gas flow directions during the withdrawal of fuel gas from the fuel gas tank, during refueling of the fuel gas tank with fuel gas and during pressure equalization, Fig. 2 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 during the withdrawal of fuel gas from the fuel gas tank, during refueling of the fuel gas tank with fuel gas and during pressure equalization, Fig. 3 a longitudinal section through two oppositely opening check valves, which are combined into a component with two valve closing elements, two valve seats and a spring, Fig. 4 a longitudinal section through two oppositely opening check valves, which are combined into a single component with a one-piece valve closing element, Fig. 5a cross-section through the component of the Figure 4 and Fig. 6 another longitudinal section through the component of the Figure 4 , but in a different switch position. Detailed description of the drawings

[0024] The one in Figure 1 The valve assembly 1 shown according to the invention serves to extract fuel gas from a fuel gas tank 2 and to refuel the fuel gas tank 2 with fuel gas, in particular with hydrogen or with natural gas.

[0025] The illustrated valve assembly 1 has a base body 3 with a connecting section 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).

[0026] The main body 3 incorporates a withdrawal path 4 for extracting fuel gas from the fuel gas tank 2 and a refueling path 5 for refueling the fuel gas tank 2. A shut-off valve 6, electrically controlled and normally closed, is integrated into the withdrawal path 4. Upstream of the shut-off valve 6 in the withdrawal direction (arrow 23), i.e., on the inlet side of the shut-off valve 6, a check valve 11 is arranged, which opens in the withdrawal direction and closes in the opposite direction. A further check valve 7 is integrated into the refueling path 5, which opens in the refueling direction (arrow 24) and closes in the opposite direction. On the outlet side of the shut-off valve 6, the withdrawal path 4 and the refueling path 5 merge to form a path 9, which leads into the gas connection 8.A pressure relief path 10 branches off from this path 9, leading upstream of the shut-off valve 6 in the direction of withdrawal into the withdrawal path 4, downstream of the check valve 11 integrated into the withdrawal path 4. The pressure equalization path 10 thus connects the outflow 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 direction of withdrawal. In the opposite direction (arrow 25), however, the check valve 12 allows pressure equalization between the outflow side and the inflow side of the shut-off valve 6. This ensures that the pressure pin on 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 unintentionally.In particular, when refueling the fuel gas tank 2 with fuel gas, the pressure p 2 on the outflow side cannot rise above the pressure p in on the inflow side of the shut-off valve 6.

[0027] In the area of ​​connection section 13, the extraction path 4 and the refueling path 5 are merged into a single path 14, so that only this one path 14 leads into the fuel gas tank 2. In this case, connection section 13 can be dimensioned very small.

[0028] To avoid further borehole intersection, the extraction path 4 and the refueling path 5 can also be connected to the storage volume of the fuel gas tank 2 as separate paths. This embodiment is shown by way of example in Figure 2. Otherwise, the embodiment corresponds to the Figure 2 the Figure 1 .

[0029] To avoid further bore intersection, the pressure equalization path 10 cannot open into path 9 within the base body 3, but instead can be led 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 is evident from the Figures 1 and 2 can be derived.

[0030] The in the Figures 1 and 2 The oppositely opening check valves 11 and 12 shown can be combined into a single component 15 to save installation space. Possible embodiments of such a component 15 are shown by way of example in the Figures 3 to 6 depicted.

[0031] A first preferred embodiment of a component 15 shows the Figure 3Here, the component 15 has two valve closing elements 18.1, 18.2, each of which is biased towards a valve seat 16, 17 by a common spring 19 located 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 housed in a valve chamber 22, which connects the component 15 to the inlet side of the shut-off valve 6. When fuel gas is drawn 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. During pressure equalization via the pressure equalization path 10, the check valve 12 with the valve closing element 18.2 opens against the spring force of the spring 19, while the valve closing element 18.1 is pressed against its valve seat 16, thus closing the check valve 11.

[0032] Another preferred embodiment of a component 15 is described in the Figures 4 to 6 The valve closing element 18 is shown here as a single 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 inlet side of the shut-off valve 6.

[0033] Since the valve closing element 18 is guided radially, it also has at least one longitudinal groove 21 opening into the circumferential groove 20 on each side of the circumferential groove 20 as a gas flow channel (see Figure 5When 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.

[0034] Figure 4 The diagram shows the valve closing element 18 in a switching position it assumes when p2 > p1. 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.

[0035] Figure 6The diagram shows the valve closing element 18 in a switching position it assumes when p2 < p1 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 routed to the gas connection 8 via the open shut-off valve 6. The check valve 12 is closed in this switching position.

[0036] A valve assembly according to the invention can comprise, in addition to the valves shown, further valves and / or components. 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 can be integrated into the valve assembly.

Claims

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

2. Valve assembly (1) according to Claim 1, characterized in that, upstream of the opening-out pressure equalization path (10) in the extraction direction, a check valve (11) that opens in the extraction direction is integrated in the extraction path (4).

3. Valve assembly (1) according to Claim 1 or 2, characterized in that the main body (3) has a connecting portion (13) for connection to the fuel-gas tank (2).

4. Valve assembly (1) according to one of the preceding claims, characterized in that the extraction path (4) and the tank-filling 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 in the extraction path (4) and the check valve (12) integrated in the pressure equalization path (10) are combined to form a component (15).

6. Valve assembly (1) according to Claim 5, characterized in that the component (15) has two valve closure elements (18.1, 18.2) between which there is arranged a spring (19) by way of which each valve closure element (18.1, 18.2) is preloaded 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-part valve closure element (18), which is movable 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 actuatable 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) having a valve assembly (1) according to one of the preceding claims, wherein preferably the valve assembly (1) is inserted sectionally into the fuel-gas tank (2) so that the common gas connection (8) is accessible from the outside.

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