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

Abstract

The invention relates to a check valve (1) for a tank valve (2), comprising a valve element (4) accommodated in a housing bore (3) for axial movement along a longitudinal axis (A), and a closing spring (5), by whose spring force the valve element (4) is pretensioned against a valve seat (6). According to the invention, a component (7) is accommodated in the housing bore (3), which component has or forms a guide pin (8) for guiding the valve element (4) and is penetrated by at least one flow opening (9). The invention further relates to a tank valve (2) for a fuel gas tank (20) with a check valve (2) according to the invention and to a fuel gas tank (20) with a tank valve (2) according to the invention.

Description

The invention relates to a check valve for a tank valve, in particular for a tank valve connected to a fuel gas tank, by means of which the fuel gas tank can be filled with fuel gas and by means of which fuel gas can be removed from the fuel gas tank. The invention further relates to a tank valve having a check valve according to the invention and to a fuel gas tank having a tank valve according to the invention. The fuel gas tank can be used in particular for storing hydrogen or natural gas.Preferred application areas of the invention are vehicles which are driven with a fuel gas, such as hydrogen or natural gas.Prior ArtHydrogen obtained in a neutral climate is becoming increasingly important as an environmentally friendly energy carrier, for example as a drive for fuel cell systems or internal combustion engines, but also for stationary applications. For the storage of hydrogen, high-pressure gas tanks with pressures of up to 700 bar are used. Tank valves are usually screwed onto these tanks, by means of which both the refueling with hydrogen and the removal of hydrogen are controlled. For this purpose, a bore is formed within the tank valve, which bore divides into two paths, namely a tank filling path via which the hydrogen reaches the gas tank during a tank filling operation, and a removal path via which hydrogen flows when hydrogen is removed from the gas tank and fed to the consuming system. The two paths are interconnected within the valve. In order to prevent hydrogen from escaping in an uncontrolled manner via the filling path when the removal path is blocked or in the event of removal, the filling path is locked by a check valve. This valve usually has an axially movable valve element and a closing spring, the spring force of which acts on the valve element in the direction of a valve seat. The check valve opens when the pneumatic pressure conditions acting on the valve element cause a force which is opposed to the spring force of the closing spring and is at least equal to the spring force.In principle, two design principles are known for the execution of these check valves. According to the first design principle, the valve element flows through the inside, and according to the second design principle, the valve element flows through the outside. In the case of the valve element through which flow takes place there are also two subvariities. In variant 1, the closing spring is flowed through. In variant 2, the gas flow is guided past the closing spring.Given a given radial installation space for the check valve, which is greatly restricted when installed in a tank valve due to the implementation of further assemblies, the maximum possible flow is likewise restricted. For rapid refueling, however, it is desirable to dethrottle the complete refueling path from the refueling station via the vehicle refueling connection, the in-vehicle lines and finally the refueling valve as much as possible. In this series connection of many individual resistors, the check valve generally represents the assembly which has the greatest flow resistance due to the narrow cross-sectional areas available and / or strong deflection losses.The present invention is concerned with the object of presenting further conceptual approaches in order to reduce the flow resistance at a sufficiently large valve lift.To achieve the object, the check valve having the features of claim 1 and the tank valve having the features of claim 10 are proposed. Advantageous further developments of the invention can be found in the respective dependent claims. Furthermore, a fuel gas tank with a tank valve according to the invention is specified.Disclosure of the InventionThe check valve proposed for a tank valve has a valve element which is accommodated in a housing bore so as to be axially movable along a longitudinal axis A, and a closing spring, by means of the spring force of which the valve element is prestressed against a valve seat. According to the invention, a component is accommodated in the housing bore, which component has or forms a guide bolt for guiding the valve element and is penetrated by at least one throughflow opening.In the case of the proposed nonreturn valve, the valve element is arranged on a guide bolt and is guided axially movably via the latter. This means that the valve element is guided on the inside and not on the outside. Given the inner diameter of the housing bore in which the valve element is accommodated, the inner guide enables a maximizing of the flow cross-sectional area, since a circular ring area with the largest possible diameter is available. Furthermore, the number of deflections of a gas stream when flowing through the nonreturn valve can be minimized, with the result that deflection losses are reduced.According to a preferred embodiment of the invention, the guide bolt is arranged centrally with respect to the longitudinal axis A and engages in a central recess of the valve element. The angular position of the valve element with respect to the component having or forming the guide bolt is thus irrelevant. The recess of the valve element is preferably fluidically connected to the housing bore via a bore. In the closed position of the valve element, the recess is filled with gas from the housing bore, which gas has to be displaced from the recess via the throttle bore during opening, so that the movements of the valve element are damped thereby. The degree of damping can be adjusted via the throttle cross section.Alternatively or additionally, it is proposed that the recess of the valve element is delimited by a stop surface facing the guide bolt. When the valve element is opened, the stop surface comes to bear against the guide bolt, so that the guide bolt limits the stroke of the valve element. In this way, a further function is integrated into the guide bolt, namely that of a stroke stop. A separate stroke stop element is thus unnecessary.The at least one flow opening, which passes through the component having or forming the guide bolt, is preferably arranged eccentrically with respect to the longitudinal axis A. Since the gas flow is guided past the valve element on the outside, the gas flow can thus be guided through the nonreturn valve in a largely deflection-free manner. The eccentric arrangement can simultaneously maximize the flow cross-sectional area of the at least one flow opening, since this is likewise arranged on a large diameter. To further maximize the flow cross-sectional area, it is proposed that a plurality of flow-through openings are arranged around the guide bolt at the same angular distance from one another.The at least one flow opening passing through the component can be designed in particular in the shape of a circle, kidney, arc or sector. If a plurality of flow-through openings are arranged around the guide bolt at the same angular distance from one another, kidney-shaped, arc-shaped or sector-shaped openings are particularly suitable for maximizing the flow cross-sectional areas.Since the valve element is guided on the inside, outer-circumference-side guide surfaces can be dispensed with. This means that the valve element can have an outer diameter AD which is smaller than an inner diameter of the housing bore accommodating the valve element at least in the region of the guidance of the valve element. This design of the valve element enables maximum flow cross-sectional areas. In addition, the valve element can be designed as a simple piston with a central recess for receiving the guide bolt.The component having or forming the guide bolt preferably has a plate-shaped section in which the at least one throughflow opening is formed. In the simplest embodiment, the component forms a plate and a bolt. The at least one flow opening is formed in the plate.Furthermore, it is proposed that the component having or forming the guide bolt is screwed or pressed into the housing bore, preferably via the plate-shaped section. The screw or press connection serves to secure the position of the component within the housing bore. In addition, if required, the component can be removed from the housing bore in a non-destructive manner, for example in order to replace it by a component whose at least one through-flow opening has a different size and / or shape. In this way, the flow cross-sectional area provided via the at least one flow opening can be varied, for example in order to adapt the flow cross-sectional area to the respective fuel gas tank when the check valve is installed in a tank valve for a fuel gas tank.Advantageously, the closing spring is axially supported on the component having or forming the guide bolt. The axial support can be effected in particular on the plate-shaped section of the component. When the component is inserted, preferably with screwing or pressing, into the housing bore, the spring prestress and thus the opening force of the nonreturn valve can thus be adjusted via the screwing or pressing depth.In a further advantageous embodiment of the proposed check valve, a friction ring is integrated into the valve element, via which friction ring the valve element is guided on the guide bolt in an axially movable manner. The friction ring reduces wear on the respective guide surfaces and also helps to prevent undesired valve noises, in particular undesired valve scrubbing.Since the proposed nonreturn valve is suitable in particular for installation in a tank valve for a fuel gas tank, a tank valve for a fuel gas tank having a nonreturn valve according to the invention is furthermore proposed. The check valve is preferably integrated into a filling path which leads via the housing bore. With the aid of the nonreturn valve, the filling path can be blocked in order to prevent uncontrolled escape of fuel gas from the fuel gas tank.The tank valve preferably has a housing in which the housing bore is formed. In this case, the check valve does not require its own housing, so that installation space-in particular in the radial direction-is saved. Alternatively, a housing of the check valve forming the housing bore can be inserted into the housing of the tank valve. The check valve can in this case be inserted into the tank valve as a pre-assembled unit, which facilitates assembly.Furthermore, preferably, a removal path is formed in the housing, which is connected to the filling path. In this embodiment, the tank valve only needs one high-pressure connection, so that this measure also helps save installation space.Furthermore, the tank valve preferably has a connecting section for connection to the fuel gas tank, and the check valve is arranged in the region of the connecting section. This measure ensures that the nonreturn valve comes to lie within the fuel gas tank when the tank valve is connected to a fuel gas tank.In addition, a fuel gas tank with a tank valve according to the invention is proposed, since the advantages of the invention are particularly clearly evident in this application. Preferably, the tank valve, preferably the connecting section of the tank valve, is inserted, in particular screwed, into the fuel gas tank. The tank valve can be inserted or screwed into a bottle neck of the fuel gas tank.DRAWINGPreferred embodiments of the invention are explained in more detail below with reference to the attached drawings. These show: FIG. 1 shows a schematic longitudinal section through a first check valve according to the invention, FIG. 2 is a cross-section through the check valve of FIG. 1, FIG. 3 shows a schematic longitudinal section through a second check valve according to the invention, FIG. 4 is a cross-section through the check valve of FIG. 3; and FIG. 5 shows a schematic longitudinal section through a fuel gas tank with a tank valve, which comprises a nonreturn valve according to the invention.DETAILED DESCRIPTION OF THE DRAWINGSFIGS. 1 and 2 show a first nonreturn valve 1 according to the invention. This has a longitudinal axis A and is inserted into a housing bore 3 of a housing 16 of a tank valve 2. The nonreturn valve 1 has an axially movable valve element 4 which is accommodated in the housing bore 3 and is prestressed against a valve seat 6 by the spring force of a closing spring 5. In FIG. 1, however, the check valve 1 is shown opened. In the open position, a fuel gas tank 20 (see FIG. 5 ) can be filled with fuel gas via the check valve 1. The arrow shown in FIG. 1 indicates the filling direction 29.In the open position, the valve element 4 is flowed around externally since it has an outer diameter AD which is smaller than an inner diameter ID of the housing bore 3. At the same time, the valve element 4 is guided internally, namely via a guide bolt 8, which is formed by a component 7 which is screwed via a plate-shaped section 13 into the housing bore 3 (screw connection 28). In the plate-shaped section 13, the component 7 has a plurality of flow openings 9, which are arranged around the guide bolt 8 at the same angular distance from one another. As can be seen from FIG. 2, the flow openings 9 have an arc shape in order to maximize the flow cross-sectional areas. In addition, the flow openings 9 are arranged radially on the outside with respect to the valve element 4, so that the gas flow guided through does not undergo any deflection. Since the closing spring 5 is arranged radially on the inside with respect to the flow openings 9, the gas flow does not have to be guided through the closing spring 5, so that flow resistances are minimized.In FIG. 1, the guide bolt 8 of the component 7 engages in a central recess 10 of the valve element 4. The recess 10 is delimited by a stop surface 12 which, when the valve element 4 is in the complete stroke, comes to bear against the guide bolt 8 and thus delimits the stroke. Accordingly, the guide bolt 8 serves at the same time as a stroke stop. In the radial direction, a guide gap 27 is formed between the valve element 4 and the guide bolt 8, which is designed to be sufficiently narrow to effect the guidance.FIGS. 3 and 4 show a further preferred embodiment of a nonreturn valve 1 according to the invention. This differs from that of FIGS. 1 and 2 in particular by a throttle bore 11 via which the central recess 10 of the valve element 4 is connected to the housing bore 3. This means that in the closed position of the valve element 4 gas reaches from the housing bore 3 into the recess 10, which gas has to be displaced again via the throttle bore 11 when the valve element 4 is opened. In this way, a damping of the stroke of the valve element 4 is achieved. Furthermore, a friction ring 14 is integrated into the valve element 4, via which friction ring the valve element 4 is guided on the guide bolt 8. The friction ring 14 reduces the guide wear. Moreover, the check valve 1 of FIGS. 3 and 4 corresponds to that of FIGS. 1 and 2, so that reference is made to the description of FIGS. 1 and 2 to avoid repetitions.FIG. 5 shows a tank valve 2 with a nonreturn valve 1, which is designed according to the invention. The nonreturn valve 1, which is illustrated only as a symbol in FIG. 5, can be embodied analogously to FIGS. 1 and 2 or FIGS. 3 and 4. The tank valve 2 is inserted, preferably screwed, into a fuel gas tank 20 via a connecting section 18 of the housing 16. A filling path 15 and a removal path 17 are formed in the housing 16 and are interconnected with one another. The check valve 1 according to the invention is integrated into the filling path 15 in order to prevent uncontrolled escape of fuel gas from the fuel gas tank 20 via the filling path 15. The filling path 15 is only for filling the fuel gas tank 20 with fuel gas, wherein the fuel gas is introduced via a filling lance 19 connected to the tank valve 2 and extending deeply into the fuel gas tank 20. As a result, the fuel gas can be distributed uniformly in the fuel gas tank 20, which contributes to avoiding a high temperature rise. To detect the temperature in the fuel gas tank 20, the tank valve 2 has a temperature sensor 26 which likewise projects into the fuel gas tank 20.Integrated into the removal path 17 of the tank valve 2 is a shut-off valve 21, which serves for the removal of combustible gas. Since the removal path 17 and the filling path 15 are interconnected with one another, the filling of the fuel gas tank 20 via the filling path 15 can lead to an undesired opening of the shut-off valve 21. In order to prevent this, a further check valve 22 is arranged upstream of the shut-off valve 21. Since the removal path 17 and the filling path 15 are interconnected with one another, only one high-pressure connection is required for connection to a high-pressure line 24. In order to prevent particles from entering the tank valve 2 via the high-pressure line 24, a filter 23 is integrated in the region of the high-pressure connection. In addition, the illustrated tank valve 2 has a further filter 23 in the removal path 17 and further valves 25, which serve primarily to meet safety requirements.

Claims

A nonreturn valve (1) for a tank valve (2), having a valve element (4) which is accommodated in a housing bore (3) so as to be axially movable along a longitudinal axis (A), and a closing spring (5), by means of the spring force of which the valve element (4) is prestressed against a valve seat (6), characterized in that the housing bore (3) accommodates a component (7) which has or forms a guide bolt (8) for guiding the valve element (4) and is penetrated by at least one throughflow opening (9).Non-return valve (1) according to Claim 1, characterized in that the guide pin (8) is arranged centrally with respect to the longitudinal axis (A) and engages in a central recess (10) of the valve element (4), which recess is preferably fluidically connected to the housing bore (3) via a throttle bore (11) and / or is delimited by a stop surface (12) facing the guide pin (8).The nonreturn valve (1) according to claim 1 or 2, characterized in that the at least one throughflow opening (9) is arranged eccentrically with respect to the longitudinal axis (A), wherein preferably a plurality of throughflow openings (9) are arranged around the guide bolt (8) at the same angular distance from one another.Non-return valve (1) according to one of the preceding claims, characterized in that the at least one throughflow opening (9) is of circular, kidney-shaped, arc-shaped or sector-shaped design.Check valve (1) according to one of the preceding claims, characterized in that the valve element (4) has an outer diameter (AD) which, at least in the region of the guidance of the valve element (4), is smaller than an inner diameter (ID) of the housing bore (3) receiving the valve element (4).The nonreturn valve (1) according to one of the preceding claims, characterized in that the component (7) having or forming the guide bolt (8) has a plate-shaped section (13), in which the at least one throughflow opening (9) is formed.Nonreturn valve (1) according to one of the preceding claims, characterized in that the component (7) which has or forms the guide bolt (8) is screwed or pressed into the housing bore (3), preferably via the plate-shaped portion (13).Non-return valve (1) according to one of the preceding claims, characterized in that the closing spring (5) is axially supported on the component (7), preferably on the plate-shaped section (13).Non-return valve (1) according to one of the preceding claims, characterized in that a friction ring (14) is integrated into the valve element (4), by means of which friction ring the valve element (4) is guided on the guide bolt (8) in an axially movable manner.Tank valve (2) for a fuel gas tank (20) having a nonreturn valve (1) according to one of the preceding claims, wherein preferably the nonreturn valve (1) is integrated into a filling path (15) which leads via the housing bore (3).Tank valve (2) according to Claim 10, characterized in that the tank valve (2) has a housing (16), in which the housing bore (3) is formed or a housing of the nonreturn valve (1) forming the housing bore (3) is inserted.Tank valve (2) according to Claim 10 or 11, characterized in that a removal path (17) is formed in the housing (16), which removal path is connected to the tank-filling path (15).Tank valve (2) according to one of Claims 10 to 12, characterized in that the tank valve (2) has a connecting section (18) for connection to the fuel gas tank (20), and the nonreturn valve (1) is arranged in the region of the connecting section (18).Fuel gas tank (20) having a tank valve (2) according to one of Claims 10 to 13, wherein the tank valve (2), preferably the connecting section (18) of the tank valve (2), is preferably inserted, in particular screwed, into the fuel gas tank (20), preferably into a bottle neck of the fuel gas tank (20).

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