Check valve for a valve assembly, valve assembly and fuel gas tank

Abstract

The invention relates to a check valve (1) for a valve assembly (2), comprising a piston (4) received in a bore (3) and guided axially displaceably through the bore (3), which interacts with a valve seat (5). According to the invention, the piston (4) is spring-free and has at least one section extending substantially in the longitudinal direction. - outer circumferential groove (6), - outer circumferential flattening (7) and / or - Bore (8) to form a flow channel extending radially outside an inner diameter (ID) S ) of the valve seat (5). The invention further relates to a valve assembly (2) for a fuel gas tank (11) and a fuel gas tank (11).

Description

[0001] The invention relates to a check valve for a valve assembly having the features of the preamble of claim 1. Furthermore, the invention relates to a valve assembly for a fuel gas tank having a check valve according to the invention, as well as to a fuel gas tank having 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.

[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] A check valve is usually integrated into the withdrawal path to prevent flow from flowing in the opposite direction to the withdrawal direction through a shut-off valve, which is also integrated into the withdrawal path, during refueling. This prevents water from entering the shut-off valve, as this could freeze and block the shut-off valve.

[0005] Spring-loaded check valves are known. These consist of a valve element that is pressed against a valve seat in the refueling direction by the spring force of a closing spring. The check valve downstream of the shut-off valve thus throttles the discharge flow when the shut-off valve is open.

[0006] The present invention is concerned with the task of providing a check valve for a valve assembly, in particular for a tank valve, that does not restrict the discharge flow. At the same time, the check valve should be as simple and compact as possible in order to reduce manufacturing costs and minimize installation space requirements.

[0007] To achieve this objective, the check valve having the features of claim 1 and the valve assembly having the features of claim 11 are proposed. Advantageous further developments of the invention can be found in the respective subclaims. Furthermore, a fuel gas tank having a valve assembly according to the invention is specified. Disclosure of the invention

[0008] The check valve proposed for a valve assembly comprises a piston accommodated in a bore and guided axially displaceably over the bore, which piston interacts with a valve seat. According to the invention, the piston is spring-loaded and has at least one substantially longitudinally extending - outer peripheral groove, - outer peripheral flattening and / or - Bore for forming a flow channel which is arranged in the radial direction outside an inner diameter of the valve seat.

[0009] The piston of the proposed check valve is spring-loaded, meaning it is not spring-loaded. Therefore, no spring acts on the piston, in particular no closing spring by which the piston is preloaded against the valve seat. In the preferred application, i.e., when the check valve is integrated into a tank valve for a fuel gas tank, the closing and opening of the check valve is achieved solely by the pneumatic forces acting on the piston. Since there is no spring force to overcome to open or keep the check valve open, only minimal forces are required. Eliminating the spring also reduces the number of parts, so that the proposed check valve has a simple and compact design.

[0010] In the proposed check valve, the arrangement of the at least one flow channel formed in the piston is selected such that it is located outside or radially outside the inner diameter of the valve seat. This ensures that a sufficiently large sealing surface remains on the piston, which securely closes the valve seat in the closed position.

[0011] The piston design with at least one groove and / or flattened portion on the outer circumference to form a flow channel has the advantage of eliminating the need for complex internal machining of the piston. The flow channel is then defined radially on the outside by the bore or the bore's inner wall.

[0012] The piston design with at least one bore to form a flow channel has the advantage that the piston is guided over its entire outer circumferential surface, since the outer circumferential surface is not interrupted by a groove and / or flattening.

[0013] In its simplest form, the check valve can consist solely of the piston, the bore, and the valve seat. The piston is guided by the bore. The opening and closing of the check valve is pneumatically controlled.

[0014] To further simplify the check valve, it is proposed that the valve seat be designed as a flat seat. The valve seat can be formed by a shoulder within the bore. Alternatively, a component forming the valve seat can be inserted into the bore. This component can, in particular, be a component of another valve, in particular a shut-off valve integrated into a discharge path. In this way, the check valve and the other valve can be arranged in a particularly space-saving manner.

[0015] Preferably, the piston of the check valve has an end face that forms a sealing surface that interacts with the valve seat. The end face can also be flat, further simplifying the manufacture of the piston.

[0016] Furthermore, a stop limiting the stroke of the piston is preferably formed within the bore. The axial displaceability of the piston is therefore limited on the one hand by the valve seat and on the other hand by the stop. This means that the piston can only move back and forth between the valve seat and the stop. The position of the stop can be used to adjust the stroke of the piston so that a gas flow flowing through the check valve is not throttling. The stop can be implemented, for example, by a shoulder within the bore accommodating the piston. To prevent throttling of the gas flow in the area of ​​the stop, the shoulder should have an inner diameter that is larger than the inner diameter of the valve seat, thus ensuring that the at least one flow channel formed in the piston remains open when the piston rests against the stop.

[0017] Alternatively or additionally, it is proposed that the at least one flow channel formed in the piston runs obliquely with respect to a longitudinal axis A of the piston, wherein the at least one flow channel has a radial distance a1 from the longitudinal axis A at its end near the valve seat that is greater than a radial distance a2 at the end of the piston remote from the valve seat. In this configuration of the at least one flow channel, the stop limiting the stroke of the piston can also have an inner diameter that is smaller than the inner diameter of the valve seat.

[0018] If the at least one flow channel is formed by a groove, the at least one groove preferably has a groove base running obliquely to the longitudinal axis A of the piston.

[0019] If the at least one flow channel is realized by a flattening, the at least one flattening preferably forms a surface running obliquely to the longitudinal axis A of the piston.

[0020] If the at least one flow channel is formed by a bore, the at least one bore preferably runs obliquely to the longitudinal axis A of the piston.

[0021] Furthermore, the piston preferably has a plurality of grooves and / or flats arranged on the outer circumference and extending longitudinally, which are arranged at equal angular spacing from one another. When the check valve is open, the gas flow flows around the piston as evenly as possible, thus avoiding transverse forces acting on the piston.

[0022] If the piston has multiple bores, these are also preferably arranged at the same angular distance from one another. It is further proposed that the multiple bores merge into a central bore. When the check valve is open, the gas flow through the piston then exits through the central bore. This allows for maximizing the stop surface of the stop limiting the stroke.

[0023] Furthermore, a valve assembly for a fuel gas tank is proposed, wherein the valve assembly comprises a check valve according to the invention. The check valve is preferably integrated into a valve block of the valve assembly, further preferably into a removal path formed in the valve block for removing fuel gas from the fuel gas tank. The advantages of the check valve according to the invention also extend to the valve assembly. In particular, the simple and compact design of the check valve proves to be advantageous, since the available installation space in a valve assembly for a fuel gas tank is generally very limited.

[0024] Preferably, a refueling path connected to the withdrawal path is formed in the valve block for filling the fuel gas tank with fuel gas, and the check valve is arranged upstream of a controllable valve in the refueling direction, which is integrated into the withdrawal path for withdrawing fuel gas. When refueling the fuel gas tank with fuel gas, the check valve can then be used to protect the additional valve integrated into the withdrawal path from water ingress.

[0025] Since the preferred 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. The compactness of the check valve integrated into the valve assembly reduces the space required by the valve assembly, allowing it to be installed in the fuel gas tank near a bottle neck.

[0026] 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 check valve according to the invention, which is integrated into a valve assembly for a fuel gas tank, during a refueling process, Fig. 2 a schematic longitudinal section through the check valve of the Fig. 1 during a withdrawal process, Fig. 3 a top view of the piston of the check valve of the Fig. 1 and Fig. 2, Fig. 4 a longitudinal section through a second piston for a check valve according to the invention, Fig. 5 a perspective view of a third piston for a check valve according to the invention, Fig. 6 a longitudinal section through a fourth piston for a check valve according to the invention and Fig. 7 a schematic representation of a fuel gas tank with a valve assembly. Detailed description of the drawings

[0027] The Fig. 1 shows a check valve 1 according to the invention, which is integrated into a valve block 12 of a valve assembly 2 for a fuel gas tank 11. The check valve 1 has a piston 4, which is received and guided in a bore 3 of the valve block 12 so as to be axially displaceable. A further valve 15, which serves to withdraw fuel gas from the fuel gas tank 11, is integrated into the bore 3. A withdrawal path 13 leads for this purpose via the bore 3 and the further valve 15. A refueling path 14 branches off from the withdrawal path 13, via which the fuel gas tank 11 can be filled with fuel gas. The check valve 1 is integrated into the withdrawal path 13 between the further valve 15 and the branching refueling path 14, so that it prevents fuel gas and thus water from entering the further valve 15 when the fuel gas tank 11 is being refueled.

[0028] The piston 4 of the check valve 1 interacts with a valve seat 5, which in this case is formed by the further valve 15. The valve seat 5 is designed as a flat seat, which has an inner diameter ID s An end face 9 of the piston 4 forms a sealing surface which, in the closed position of the check valve 1 (see Fig. 1) lies flat against the valve seat 5 and thus closes the valve seat 5. When refueling (see Fig. 1), the piston 4 is held in the closed position solely by the pneumatic forces acting on the piston 4. Therefore, a closing spring is not required, so that the check valve 1 has a simple and compact design.

[0029] In order to remove fuel gas from the fuel gas tank 11, the additional valve 15 is opened so that fuel gas flows out of the fuel gas tank 11 and lifts the piston 4 from the valve seat 5. The stroke of the piston 4 is limited by a stop 10, which is formed by a shoulder of the bore 3 (see Fig. 2). In the open position of the check valve 1, the piston 4 rests against the stop 10 and the extraction of the fuel gas takes place via at least one flow channel, which is formed by a groove 6 of the piston 4 arranged on the outer circumference and extending in the longitudinal direction (see also Fig. 3). The flow channel is limited radially outwards by the valve block 12 forming the bore 3. To prevent the flow channel from being blocked by the stop 10, the stop 10 has an inner diameter ID A which is larger than the inner diameter ID Sof the valve seat 5. The flow channel thus ends within the inner diameter ID A of the attack 10.

[0030] In the Fig. 4 to 6 is each a variant of the piston 4 of the Fig. 3. These are described below.

[0031] The piston 4 of the Fig. 4 also has a groove 6 for forming a flow channel, but the groove 6 has a groove base 16 running obliquely to the longitudinal axis A of the piston 4. This means that the flow channel, at its end near the valve seat, has a radial distance a1 from the longitudinal axis A that is greater than a radial distance a2 at the end of the piston 4 remote from the valve seat. The end near the valve seat is defined by the end face 9 of the piston 4, which forms the sealing surface interacting with the valve seat 5.

[0032] The piston 4 of the Fig. 5 has a flattened portion 7 instead of a groove 6. The flattened portion 7 forms a surface 17 extending obliquely to the longitudinal axis A, so that here too the flow channel at its end near the valve seat has a radial distance a1 from the longitudinal axis A that is greater than a radial distance a2 at the end of the piston 4 remote from the valve seat. The end face 9 defines the end near the valve seat.

[0033] The piston 4 of the Fig. 6 has a bore 8 for forming a flow channel, wherein the bore 8 runs obliquely to the longitudinal axis A of the piston 4 and ends in a centrally arranged further bore 18. This comes within the inner diameter ID A of the stop 10 so that throttling of the fuel gas flow during extraction by the stop 10 is prevented.

[0034] The Fig. 7 shows, by way of example, a valve assembly 2 connected to a fuel gas tank 11. The valve assembly 2 has a valve block 12, which is inserted, in particular screwed, into the fuel gas tank 11 in sections. A withdrawal path 13 and a refueling path 14 are formed in the valve block 12. A valve 15 is integrated into the withdrawal path 13 and is opened to withdraw fuel gas from the fuel gas tank 11. A check valve 15 is arranged downstream of the valve 15 in the withdrawal direction and is intended to prevent water from entering the valve 15 when the fuel gas tank 11 is refueled with fuel gas via the refueling path 14. The check valve 1 is preferably designed according to the invention so that only pneumatic forces act on the piston 4 of the check valve 1. This has the advantage that - especially with small withdrawal quantities - the pressure difference acting on the piston 4 of the check valve 1 is also small.

[0035] The Fig. The valve assembly 2 shown in Fig. 7 has a plurality of further components, in particular further valves 19 and filters 20, which are not essential to the invention and are therefore not described in more detail.

Claims

[1] Check valve (1) for a valve assembly (2), comprising a piston (4) received in a bore (3) and guided axially displaceably over the bore (3), which cooperates with a valve seat (5), characterized by that the piston (4) is spring-loaded and has at least one substantially longitudinally extending - outer peripheral groove (6), - outer peripheral flattening (7) and / or - bore (8) for forming a flow channel which extends in the radial direction outside an inner diameter (ID S ) of the valve seat (5). [2] Check valve (1) according to claim 1, characterized by that the valve seat (5) is designed as a flat seat. [3] Check valve (1) according to claim 1 or 2, characterized by that the piston (4) has an end face (9) which forms a sealing surface cooperating with the valve seat (5). [4] Check valve (1) according to one of the preceding claims, characterized by that a stop (10) limiting the stroke of the piston (4) is formed within the bore (3), which stop is realized, for example, by a shoulder. [5] Check valve (1) according to one of the preceding claims, characterized by that the at least one flow channel formed in the piston (4) runs obliquely with respect to a longitudinal axis (A) of the piston (4), wherein the at least one flow channel has a radial distance (a1) from the longitudinal axis (A) at its end near the valve seat which is greater than a radial distance (a2) at the end of the piston (4) remote from the valve seat. [6] Check valve (1) according to one of the preceding claims, characterized by that the at least one groove (6) has a groove base (16) running obliquely to the longitudinal axis (A) of the piston (4). [7] Check valve (1) according to one of the preceding claims, characterized bythat the at least one flattening (7) forms a surface (17) extending obliquely to the longitudinal axis (A) of the piston (4). [8] Check valve (1) according to one of the preceding claims, characterized by that the at least one bore (8) runs obliquely to the longitudinal axis (A) of the piston (4). [9] Check valve (1) according to one of the preceding claims, characterized by that the piston (4) has a plurality of grooves (6) and / or flats (7) arranged on the outer circumference and extending in the longitudinal direction, which are arranged at the same angular distance from one another. [10] Check valve (1) according to one of the preceding claims, characterized by that the piston (4) has a plurality of bores (8) which are arranged at the same angular distance from one another and / or which combine to form a central bore. [11] Valve assembly (2) for a fuel gas tank (11), comprising a check valve (1) according to one of the preceding claims, wherein preferably the check valve (1) is integrated into a valve block (12) of the valve assembly (2), further preferably into a removal path (13) formed in the valve block (12) for removing fuel gas from the fuel gas tank (11). [12] Valve assembly (2) according to claim 11, characterized by in that a refueling path (14) connected to the withdrawal path (13) for filling the fuel gas tank (11) with fuel gas is formed in the valve block (12), and the check valve (1) is arranged upstream in the refueling direction of a controllable valve (15) which is integrated into the withdrawal path (13) for withdrawing fuel gas. [13] Fuel gas tank (11) with a valve assembly (2) according to claim 11 or 12.

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