Shut-off valve for hydrogen tank systems, compressed gas containers and hydrogen tank systems

Description

[0001] The invention relates to a shut-off valve for hydrogen tank systems having at least one compressed gas container. Furthermore, the invention relates to a compressed gas container for a hydrogen tank system having a shut-off valve according to the invention, as well as to a hydrogen tank system having at least one compressed gas container and a shut-off valve according to the invention. State of the art

[0002] Mobile hydrogen tank systems for motor vehicles are known for converting hydrogen into fuel cells or hydrogen combustion engines. In the event of a pipeline break or an accident, the hydrogen tanks must be sealed with shut-off valves to prevent uncontrolled hydrogen leakage. The shut-off valves must therefore be designed as self-closing valves in accordance with applicable guidelines.

[0003] The automatic closing function is usually realized with the help of a spring that acts directly or indirectly on a reciprocating valve piston of the shut-off valve in the closing direction.

[0004] The opening function is usually achieved indirectly via an electromagnetically actuated control valve. By opening the control valve, the control pressure applied to the valve piston of the main valve can be reduced, exerting a closing force on the valve piston. As the pressure drop increases, the main valve can thus open. The pressure drop can be achieved via a comparatively small seat diameter of the control valve, so that opening the control valve requires a comparatively low force. At the same time, the seat diameter of the main valve can be increased to achieve large volume flows, which is advantageous in a hydrogen tank system. However, if the control valve's discharge flow is fed to the valve outlet of the main valve, there is a risk that the same pressure will prevail everywhere when the valve is fully open and that the shut-off valve will close due to its automatic closing function.As the load decreases, the pressure drops again and the shut-off valve opens. This constant opening and closing of the shut-off valve leads to increased wear in the seat area of the conventional plastic or elastomer seats used in hydrogen applications.

[0005] WO 2020 / 120072 A1, for example, describes such a shut-off valve.

[0006] Based on the above-mentioned prior art, the present invention is based on the object of specifying a shut-off valve for hydrogen tank systems which has a controlled opening behavior and at the same time requires as little installation space as possible, in particular in order to enable the integration of the shut-off valve into the bottle neck of a compressed gas container designed as a compressed gas cylinder.

[0007] To achieve this objective, the shut-off valve is provided with the features of claim 1. Advantageous developments of the invention are set forth in the subclaims. Furthermore, a compressed gas container with a shut-off valve according to the invention and a hydrogen tank system with at least one compressed gas container and a shut-off valve according to the invention are proposed. Disclosure of the invention

[0008] The proposed shut-off valve comprises a main valve and a control valve for controlling the main valve. The main valve has a reciprocating valve piston that interacts with a valve seat and defines a control chamber at its end facing away from the valve seat. The control chamber is connected to a storage volume of the compressed gas container via an inlet throttle and, depending on the switching position of the control valve, can be connected to a gas outlet via an outlet throttle. The main valve further has a solenoid coil, by means of which an opening and / or holding force acting on the valve piston can be generated. According to the invention, the main valve and the control valve are arranged coaxially and separated from one another by an axial gap in which a preferably disc-shaped body made of a non-magnetic material is received.The body serves to provide magnetic separation between the magnetic circuit of the control valve and the magnetic coil housed in the valve housing to generate the holding force acting on the valve piston.

[0009] The opening and / or holding force acting on the main valve's valve piston can eliminate the disadvantages of indirect control described above. In particular, the main valve can be prevented from closing if the same pressure prevails throughout the fully open position. The solenoid coil acting on the valve piston can thus temporarily override the shut-off valve's automatic closing function.

[0010] Since the holding force of the solenoid coil is only required once the main valve is largely unthrottled, a comparatively small holding force is sufficient. The stroke of the valve piston also results in a minimal air gap, allowing the use of a small solenoid coil. The small size of the solenoid coil enables the desired miniaturization of the shut-off valve.

[0011] In the event of complete pressure equalization between the gas outlet of the shut-off valve and the storage pressure in the compressed gas cylinder, no pressure reduction in the control chamber and thus no pneumatic opening is possible. Therefore, the magnetic force on the main valve is advantageously dimensioned so large that the main valve can be magnetically opened against the closing force of a spring, enabling a defined open position of the main valve throughout operation. Depending on the design objective, a combination of pneumatic and magnetic opening on the main valve can also be advantageously implemented.

[0012] According to a preferred embodiment of the invention, the magnetic coil is annular and arranged coaxially with the valve piston of the main valve. The magnetic coil can thus be used to generate a magnetic field whose magnetic force acts evenly on the valve piston.

[0013] Furthermore, the solenoid coil is preferably located opposite the valve piston in the control chamber. This means that the solenoid coil is arranged at an axial distance from the valve piston. The stroke of the valve piston reduces the distance and thus the air gap between the solenoid coil and the valve piston. At maximum stroke, the air gap is thus minimal, and only a small force is required to hold the valve piston in this position.

[0014] Advantageously, the solenoid coil is integrated into a valve housing that defines the control chamber and forms the outlet throttle. The solenoid coil can thus be positioned close to the control chamber. Furthermore, the space around the outlet throttle can be used to accommodate the solenoid coil. Therefore, the outlet throttle is preferably routed through the solenoid coil. This creates a particularly compact arrangement.

[0015] To ensure the main valve closes securely, it is proposed that the valve piston of the main valve be biased toward the valve seat by the spring force of a spring. For this purpose, the spring is preferably supported on the one hand on the valve piston and on the other hand on a sealing sleeve which surrounds the end of the valve piston facing the control chamber to define the control chamber. The control chamber is thus preferably defined in the axial direction by the valve piston, on the other hand by the valve housing accommodating the solenoid coil, and in the radial direction by the sealing sleeve. The main valve can therefore be of comparatively simple construction. The sealing sleeve also enables easy compensation of tolerances resulting from manufacturing and / or assembly, particularly misalignment errors.

[0016] The inlet throttle, through which the control chamber is connected to a storage volume of the compressed gas cylinder, compensates for the increase in volume of the control chamber caused by the closing movement of the valve piston and thus ensures reliable closing of the main valve. To reduce the number of parts, the inlet throttle can be formed by a guide gap through which the valve piston of the main valve is guided. To reduce the accuracy requirements for the guide, a sealing element can be arranged in the area of the guide. In this case, the inlet throttle is implemented separately by a fluidically conductive connection, in particular a throttle bore.

[0017] The control valve is advantageously electromagnetically actuated and has an annular magnetic coil for acting on a magnetic armature, which is coupled to a valve element of the control valve or forms a valve element. If the magnetic armature and the valve element are separate components that are merely coupled, different materials can be used to construct the components. This allows the optimal material to be selected for each function. If the magnetic armature also forms the valve element, the number of components can be reduced, thus simplifying the design of the control valve.

[0018] Analogously, the valve piston of the main valve can also be formed by a magnetic armature or be coupled to a magnetic armature in order to act on it by means of the magnetic coil assigned to the valve piston.

[0019] To close the control valve, it preferably comprises a closing spring, so that closing is effected by spring force. For this purpose, the closing spring is preferably axially supported on the solenoid armature of the control valve. Furthermore, the solenoid armature and the valve element, which may be coupled to the solenoid armature, are preferably axially preloaded by the spring force of the closing spring toward a sealing seat formed by the valve housing that defines the control chamber. In this way, a compact arrangement can also be created in the axial direction.

[0020] Furthermore, a compressed gas container for a hydrogen tank system with a shut-off valve according to the invention is proposed. Since the shut-off valve requires little space, it can be easily integrated into the compressed gas container. The shut-off valve is preferably arranged in the region of a container outlet of the compressed gas container. In the event of a line break or an accident, the shut-off valve can then be used to close the compressed gas container, preventing uncontrolled gas escape. The container outlet area can, in particular, have the shape of a bottle neck. A container outlet shaped in this way is particularly stable and thus particularly well-suited as an installation location for the shut-off valve.

[0021] By integrating a shut-off valve according to the invention into a compressed gas container, safety requirements are met, as it closes automatically. On the other hand, large hydrogen volume flows are enabled via the valve seat of the main valve, as this is indirectly controlled by an electromagnetically actuated control valve. The additional solenoid provided can also generate a holding force that prevents the shut-off valve from closing undesirably, especially when fully open. Since only a low holding force is required, a small solenoid coil can be used, which facilitates a miniaturized design of the shut-off valve.

[0022] Furthermore, a hydrogen tank system comprising at least one compressed gas container and a shut-off valve according to the invention for shutting off the compressed gas container is proposed. Advantageously, the hydrogen tank system comprises several similar compressed gas containers, each of which is equipped with a shut-off valve according to the invention. The compressed gas containers can thus be shut off and replaced independently of one another as needed.

[0023] A preferred embodiment of the invention is explained in more detail below with reference to the accompanying drawing. This shows a schematic longitudinal section through a shut-off valve according to the invention in the closed position. Detailed description of the drawing

[0024] The shut-off valve 1 for a compressed gas container 2 shown in the figure has a main valve 3 and a control valve 4. The control valve 4 is electromagnetically actuated.

[0025] The main valve 3 has a reciprocating valve piston 6 that interacts with a valve seat 5. The end 7 of the valve piston 6 facing away from the valve seat 5 is accommodated in a sealing sleeve 16, which, together with the valve piston 6 and a valve housing 14, defines a control chamber 8. The sealing sleeve 16 is axially preloaded against the valve housing 14 by the spring force of a spring 15. At the same time, the spring force of the spring 15 presses the valve piston 6 against the valve seat 5.

[0026] To open the main valve 3, the control valve 4 must first be opened. For this purpose, a solenoid coil 17 is energized, creating a magnetic field whose magnetic force acts on a reciprocating magnet armature 18 that is coupled to a valve element 19 of the control valve 4. The movement of the magnet armature 18 thus opens the control valve 4. When the control valve 4 is open, gas flows out of the control chamber 8 via an outlet throttle 11 formed in the valve housing 14, so that the pressure in the control chamber 8 drops and the force ratios acting on the valve piston 6 enable the main valve 3 to open. Gas then flows out of a storage volume 10 of the compressed gas container 2 via the valve seat 5 into a gas outlet 12. Since the discharge volume of the control valve 4 is also introduced into the gas outlet 12, the same pressure is achieved everywhere when the shut-off valve 1 is fully open. This means that the pressure in control chamber 8 also rises again.To prevent the shut-off valve 1 from accidentally closing, an additional solenoid coil 13 is integrated into the valve housing 14, which generates a holding force acting on the valve piston 6. The solenoid coil 13 is compact, since holding the main valve 3 open does not require a great deal of force. This is especially true since the air gap between the solenoid coil 13 and the valve piston 6 is very small when the main valve 3 is completely de-throttled.

[0027] To close the shut-off valve 1, the current supply to the solenoid coil 17 of the control valve 4 is stopped, so that a closing spring 20 returns the solenoid armature 18 including the valve element 19 to its respective starting position and closes the control valve 4. When the control valve 4 is closed, no more gas can flow out of the control chamber 8 via the outlet throttle 11, but only gas can flow into the control chamber 8 via an inlet throttle 9, which connects the control chamber 8 to the storage volume 10 of the compressed gas container 2, so that the pressure in the control chamber 8 rises again. The pressure exerts a closing force on the valve piston 6 of the main valve 3, which, together with the spring force of the spring 15, leads to the closing of the main valve 3.

[0028] In order to separate the magnetic coil 13 assigned to the valve piston 6 of the main valve 3 from the magnetic circuit of the control valve 4, an axial gap 21 is provided between the control valve 4 and the valve housing 14, in which a disc-shaped body 22 made of a non-magnetic material is arranged.

[0029] The shut-off valve 1 shown in the figure has a simple design and requires little installation space, so that it can be integrated into the compressed gas container 2 in the area of a container outlet 23.

Claims

1. Shut-off valve (1) for hydrogen tank systems with at least one compressed gas tank (2), comprising a main valve (3) and a control valve (4) for controlling the main valve (3), wherein the main valve (3) has a reciprocating valve piston (6) which interacts with a valve seat (5) and delimits, at its end (7) facing away from the valve seat (5), a control chamber (8) which is connected via an inlet throttle (9) to a storage volume (10) of the compressed gas tank (2) and can be connected to a gas outlet (12) via an outlet throttle (11), depending on the switching position of the control valve (4), and wherein the main valve (3) has a solenoid coil (13), by means of which an opening and / or holding force acting on the valve piston (6) can be generated, characterized in that the main valve (3) and the control valve (4) are arranged coaxially and are separated from each other by an axial gap (21), in which a preferably disc-shaped body (22) made from a non-magnetic material is received.

2. Shut-off valve (1) according to Claim 1, characterized in that the solenoid coil (13) is of annular configuration and is arranged coaxially with respect to the valve piston (6).

3. Shut-off valve (1) according to Claim 1 or 2, characterized in that the solenoid coil (13) lies opposite the valve piston (6) on the control chamber (8).

4. Shut-off valve (1) according to one of the preceding claims, characterized in that the solenoid coil (13) is integrated into a valve housing (14) which delimits the control chamber (8) and forms the outlet throttle (11) which is preferably passed through by the solenoid coil (13).

5. Shut-off valve (1) according to one of the preceding claims, characterized in that the valve piston (6) of the main valve (3) is loaded in the direction of the valve seat (5) by the spring force of a spring (15) which is preferably supported firstly on the valve piston (6) and secondly on a sealing sleeve (16) which surrounds the end (7) of the valve piston (6) in order to delimit the control chamber (8).

6. Shut-off valve (1) according to one of the preceding claims, characterized in that the control valve (4) is electromagnetically operable, and has an annular solenoid coil (17) for acting on a magnet armature (18) which is coupled to a valve element (19) of the control valve (4) or forms a valve element (19).

7. Shut-off valve (1) according to one of the preceding claims, characterized in that the control valve (4) comprises a closing spring (20) which is preferably supported axially on the magnet armature (18).

8. Compressed gas tank (2) for a hydrogen tank system with a shut-off valve (1) according to one of the preceding claims, wherein the shut-off valve (2) is preferably arranged in the region of a container outlet (23).

9. Hydrogen tank system with at least one compressed gas tank (2) and a shut-off valve (1) according to one of Claims 1 to 7 for shutting off the compressed gas tank (2).