Check valve

Abstract

A check valve, in particular of a hydrogen refuelling system, has an inlet and an outlet which define a flow direction that extends from the inlet to the outlet. The check valve has a piston (6), which is arranged such that it can move relative to the inlet and outlet, for opening and closing the inlet of the check valve, wherein the piston (6) defines a piston axis (63) with a first end facing the inlet and a second end facing the outlet. The piston (6) has an outer surface along which flows a fluid flowing through the check valve in the flow direction. The outlet has outlet channels (35) to allow the fluid to flow outwards out of the check valve, wherein all of the outlet channels (35) of the outlet run obliquely to the piston axis (63). The check valve can be used for high pressures and allows gentle closing even with a reversal of the pressure action. In particular, it can be used in hydrogen filling stations.

Description

[0001] TITLE

[0002] CHECK VALVE

[0003] TECHNICAL FIELD

[0004] The present invention relates to a check valve, in particular a check valve of a hydrogen refueling system, and a unit of a hydrogen refueling system.

[0005] STATE OF THE ART

[0006] A hydrogen refueling facility, particularly a hydrogen filling station, has one or more pressurized tanks containing liquid or compressed gaseous hydrogen for refueling motor vehicles or trains. These pressurized tanks are also called banks or storage banks.

[0007] To fully refuel a vehicle as quickly as possible, hydrogen is drawn sequentially from several storage banks. The further the vehicle's refueling progresses, the higher the pressure in the storage banks must be. The pressures in the individual storage banks therefore vary; typically, they are 350 bar, 500 bar, 700 bar, and 1000 bar. However, storage banks with other pressures are also possible.

[0008] In order to refuel the vehicle as quickly as possible, switching to storage banks with higher pressures is necessary as quickly as possible.

[0009] High-pressure valves, especially pilot-operated solenoid valves, enable fast switching times and thus also rapid switching of storage banks. Switching times range from 10 ms to 200 ms. Check valves prevent backflow of hydrogen from a dispensing line connected to the vehicle tank to the storage bank.

[0010] The rapid opening of the accumulator banks leads to high pressure surges or pressure pulses in the accumulator bank line. These high pressure surges can damage the downstream non-return valve of the accumulator bank. In particular, the sealing element can be displaced in the direction of flow, preventing the non-return valve from closing.

[0011] If a change to a higher pressure level and thus to a different storage bank occurs during refueling, the check valve also experiences high pressure surges or pressure pulses in the counterflow direction. These pressure surges are caused by the increase in pressure in the line. Solenoid valves usually close more slowly than they open. This means that the check valve of a first or upstream storage bank is not yet fully closed when a solenoid valve of a second or subsequent storage bank is already fully open. The pressure surge acting on the check valve closes the check valve with a relatively large force. Its piston is often pressed into the sealing seat with great force. This massively reduces the service life of the check valve. The sealing seat can even be damaged, so that the check valve no longer closes optimally.This limits the maximum pressure that can exist in a storage bank.

[0012] These high pressure surges in the flow direction, but especially in the counterflow direction, place high demands on the check valves and reduce their service life. This causes high maintenance costs and can lead to fueling system failures.

[0013] Check valves are known in the prior art in which a steel piston, through which fluid flows, contacts an elastomeric or thermoplastic sealing element. Steel pistons with an elastomeric or thermoplastic sealing element are also known. At high pressures, such as those used in hydrogen filling stations, there is a risk that the sealing element will fly out or at least be displaced.

[0014] Check valves with a steel piston through which the fluid flows and which hits a steel seat have the disadvantage that they seal less effectively than soft seats with an elastomer or thermoplastic sealing element.

[0015] DE 10 2016 014 312 A1 discloses a check valve with a piston made of PEEK (polyetheretherketone) interspersed with inclined channels. It is used particularly in piston pumps and compressors. Check valves with pistons surrounded by fluid flow are also known. However, they are not protected against backflow and are therefore unsuitable for pressures such as those found in hydrogen refueling systems.

[0016] PRESENTATION OF THE INVENTION

[0017] It is therefore an object of the invention to provide a check valve, in particular for hydrogen refueling systems, which has a gentle closing behavior even when pressurized in the opposite direction and has the longest possible service life when subjected to high pressure surges.

[0018] This object is achieved by a check valve having the features of patent claim 1 and a unit of a hydrogen refuelling system having the features of patent claim 19.

[0019] The check valve according to the invention has an inlet and an outlet, which define a flow direction extending from the inlet to the outlet. The check valve has a piston arranged to be movable relative to the inlet and outlet for opening and closing the inlet of the check valve. The piston defines a piston axis with a first end facing the inlet and a second end facing the outlet. The piston has an outer surface along which a fluid flows through the check valve in the flow direction. The outlet has outlet channels to allow the fluid to flow out of the check valve, wherein all outlet channels of the outlet run obliquely, i.e., at an angle other than 0°, to the piston axis.

[0020] Thanks to the outlet channels running at an angle to the piston axis, a fluid flowing into the check valve at high pressure from the outlet side cannot exert a high pressure pulse on the piston. Thus, if a fluid flows in in the opposite direction, i.e., from the outlet side, the check valve still closes relatively gently.

[0021] When a fluid is applied to the piston in the direction of flow, the fluid flows around the piston. The fluid flows along the outer surface of the piston. This minimizes pressure pulses on the piston and reduces pressure losses. A large flow rate through the check valve is possible.

[0022] The check valve is suitable for various applications, particularly those with high pressure pulses in the counterflow direction. The check valve is particularly suitable for use in hydrogen refueling systems, especially in hydrogen refueling stations for motor vehicles. The check valve can be used at pressures up to 1000 bar and more. Thanks to the increased service life of the check valve, maintenance intervals and maintenance costs of a system, especially a hydrogen refueling system, are reduced. Failures of such systems are reduced or even avoided. Other areas of application include hydrogen tank trucks and electrolyzers for hydrogen production.

[0023] The check valve according to the invention is also suitable for retrofitting systems because it is relatively space-saving and has a simple design.

[0024] Preferably, the flow completely surrounds the piston, i.e. no portion of the fluid flows through the piston. Preferably, when the piston is in the open position, only one channel is exposed, extending from the inlet to the outlet and extending exclusively along the outer surface of the piston. Preferably, the piston only opens one channel between the inlet and outlet, extending along the outer surface of the piston. This optimizes the damping of the piston when the valve opens and closes and enables a high flow rate in the direction of flow from the inlet to the outlet. Furthermore, the piston can be designed to be robust and therefore durable, as it is not interspersed with any channels that could weaken it.

[0025] The piston is preferably guided for movement. In a preferred embodiment, the piston has radially projecting ribs on its circumference, with the outer surface along which the fluid flows preferably being arranged between the ribs. These ribs minimize eddies in the fluid flow. They preferably guide the piston in its movement. In some embodiments, at least one of the ribs is mounted in the valve body.

[0026] The check valve preferably has a valve body in which the piston is movably arranged, the piston being guided by the valve body. If ribs are present on the piston, they preferably extend to the inner wall of the valve body to guide the piston and conduct the fluid. Depending on the design, at least one of the ribs, preferably all of the ribs, is mounted in the valve body.

[0027] Preferably, there are as many exhaust ports as there are surfaces between the ribs. This optimizes fluid flow along the piston.

[0028] The valve body preferably has a sealing seat on which the piston rests when the check valve is closed. The sealing seat is preferably made of metal. An elastomeric seal, such as an O-ring, is preferably not present on either the sealing seat or the piston. The piston preferably seals without an elastomeric seal.

[0029] In a preferred embodiment, at least part of the piston is made of a plastic, in particular a high-performance plastic, preferably PEEK. Preferably, the entire piston is made of plastic, in particular a high-performance plastic, preferably PEEK. This increases the damping properties of the piston. Furthermore, the piston is relatively lightweight. The moving mass of the check valve is reduced. The opening and closing speed, as well as the impact resistance, are increased. An additional elastomeric sealing element between the piston and the sealing seat can be omitted.

[0030] If the sealing seat is made of metal, the sealing effect is optimized when using a plastic piston, especially PEEK. High-performance plastics, especially PEEK, are resistant to a very wide temperature range, including both negative and positive °C. This makes the check valve ideal for continuous use with hydrogen.

[0031] Preferably, a coupling element is provided, which is attached to a housing of the check valve, wherein the coupling element has through-openings that form the outlet channels. The flow in the direction of flow from the check valve through the outlet channels can thereby be maximized. This is particularly optimal for hydrogen refueling systems, as refueling time can be minimized. Pressure losses are minimized thanks to outlet channels with large diameters. Preferably, the piston is guided in the valve body and arranged at a distance from the coupling element.

[0032] The coupling element can be designed, for example, as a hollow screw that can be screwed into or onto the housing. This simplifies installation.

[0033] Preferably, the valve body forms the housing of the check valve.

[0034] Preferably, a return spring is provided that presses the piston into a sealing seat to close the check valve. The return spring is preferably arranged with a first end in the piston and a second end in the coupling element. Preferably, the return spring is arranged in the piston, surrounded by the outlet channels. This is an extremely compact arrangement, so that the size of the check valve is minimized.

[0035] The inventive unit of a hydrogen refueling system has a first line for connecting a first storage bank to a dispensing line and a second line for connecting a second storage bank to the same dispensing line. A filling direction leads from the first storage bank and the second storage bank to the dispensing line. A first high-pressure valve, in particular a pilot-valve-controlled solenoid valve, and a first check valve are arranged in the first line, wherein the first check valve is arranged downstream of the first high-pressure valve in the filling direction. A second high-pressure valve, in particular a pilot-valve-controlled solenoid valve, and a second check valve are arranged in the second line, wherein the second check valve is arranged downstream of the second high-pressure valve in the filling direction. The first check valve and the second check valve are check valves as described above.The filling direction is preferably the above-mentioned flow direction through the check valve.

[0036] Further embodiments are specified in the dependent claims.

[0037] BRIEF DESCRIPTION OF THE DRAWINGS

[0038] A preferred embodiment of the invention is described below with reference to the drawings, which are for illustrative purposes only and are not to be interpreted as limiting. The drawings show: Figure 1 shows a schematic representation of a unit of a hydrogen refueling system;

[0039] Figure 2 is a perspective view of a check valve according to the invention with an inlet and an outlet line;

[0040] Figure 3 shows a longitudinal section through the check valve according to Figure 2 in the closed state;

[0041] Figure 4 shows a further longitudinal section through the check valve according to Figure 2 in the closed state;

[0042] Figure 5 shows a longitudinal section through the check valve according to Figure 2 in the open state;

[0043] Figure 6 is a first perspective view of a piston of the check valve according to Figure 2;

[0044] Figure 7 shows a first view of an end face of the piston according to Figure 6;

[0045] Figure 8 is a second perspective view of the piston according to Figure 6;

[0046] Figure 9 shows a second view of an end face of the piston according to Figure 6;

[0047] Figure 10 is a side view of the piston according to Figure 6;

[0048] Figure 11 is a first perspective view of a coupling element of the check valve according to Figure 2;

[0049] Figure 12 shows a first view of an end face of the coupling element according to Figure 11;

[0050] Figure 13 shows a second perspective view of the coupling element according to Figure 11;

[0051] Figure 14 shows a second view of an end face of the coupling element according to Figure 11 and

[0052] Figure 15 is a side view of the coupling element according to Figure 11.

[0053] DESCRIPTION OF PREFERRED EMBODIMENTS

[0054] Figure 1 schematically shows a filling station with two hydrogen storage banks B1 and B2. Typically, three, four, or more storage banks B1 and B2 are present per filling station.

[0055] The individual hydrogen storage banks B1 and B2 have different pressures. The pressures are preferably 350 bar, 500 bar, 700 bar, and 1000 bar. In this example, the first storage bank B1 has a lower pressure than the second storage bank B2.

[0056] A supply line 20 leads from each storage bank B1, B2 via valves HV1, HV2, CV1, CV2 to an intermediate line 21 and then to a common discharge line 22, which leads to a discharge point (not shown). This is the filling direction when refueling a motor vehicle (also not shown), as well as the flow direction through the valves HV1, HV2, CV1, CV2. The supply line 20, the intermediate line 21, and the discharge line 22 are preferably metal pipes. They are preferably rigid.

[0057] Not shown in Figure 1 are a cryopump or a compressor for compressing the hydrogen connected to the storage banks B1, B2 as well as the filling stations, also called fuel pumps, connected to the storage banks B1, B2 via the filling line 22, at which the motor vehicles can be refuelled with hydrogen.

[0058] Each storage bank B1, B2 is assigned a high-pressure valve HV1, HV2, preferably a pilot-operated solenoid valve. A corresponding check valve CV1, CV2 is arranged downstream of the high-pressure valve HV1, HV2 in the flow direction. When pressurized, the check valve CV1, CV2 opens toward the draw-off line 22 and prevents fluid flow in the opposite direction, i.e., it prevents backflow toward the storage banks B1, B2.

[0059] When refueling a motor vehicle, hydrogen is first drawn from the storage bank with the lowest pressure—in this example, from the first storage bank B1. To do this, the corresponding first high-pressure valve HV1 is opened, which also opens the corresponding first check valve CV1 due to the pressure of the fluid flow, in this case hydrogen, in the direction of flow. The second solenoid valve HV2 and thus also the second check valve CV2 are closed. The fluid, in this case hydrogen, flows from the first storage bank B1 via the supply line 20 and the intermediate line 21 to the dispensing line 22 and thus to the dispensing point.

[0060] When the pressure in the motor vehicle's tank rises, the pressure difference between the first storage bank B1 and the tank decreases. To continue to enable rapid refueling, the system switches to the second storage bank B2, which has a higher pressure. The first high-pressure valve HV1 is therefore closed and the second high-pressure valve HV2 and thus also the second check valve CV2 are opened. Since the first solenoid valve HV1 and / or first check valve CV1 close more slowly than the other valves open, the now increased pressure in the intermediate line 21 acts on the first check valve CV1, which is not yet fully closed. This pressure surge accelerates the closing element of the check valve CV1, usually a piston, so that it strikes the sealing seat at high speed. As mentioned at the beginning, this can damage the check valve or at least massively shorten its service life.

[0061] Figures 2 to 5 show an example of a check valve CV according to the invention, which can be used as the first and second check valves CV1, CV2 in the arrangement shown in Figure 1. However, it can also be used in other applications where good damping of the piston movement or a smooth piston movement at least in the direction of flow and / or in the counterflow direction is advantageous. The valve can also be used for other fluids and in other systems.

[0062] The check valve CV has a valve body 1, which forms a housing of the check valve CV. The valve body 1 is preferably formed in one piece. It is preferably made of metal, in particular steel.

[0063] It has an interior space in which a piston 6 is arranged to be movable in the longitudinal direction of the valve body 1. A coupling element 3 is held on or in the valve body 1. In this example, the coupling element 3 is designed as a hollow screw and is screwed into an end of the valve body 1 on the outlet side in the flow direction via an external thread 31. The coupling element 3 has a base body 30 and a flange 32, wherein the flange 32 preferably rests on the outer end face of the valve body 1. The coupling element 3 has an internal thread 320, preferably in the region of the flange 32. In the interior space of the coupling element 3, a circumferential beveled edge 321 is preferably formed, which forms a cone tapering in the counterflow direction.

[0064] The intermediate line 21 forms an outlet line of the check valve CV. It is connected to the valve body 1 via a first connecting element 4 with an external thread 40 and a first bushing 80 with an internal thread 81. In this example, it is connected to the coupling element 3 for this purpose. The intermediate line 21 preferably rests against the circumferential beveled edge 321 and is thus secured against rotation and held fixed in the longitudinal direction.

[0065] As already mentioned, the intermediate line 21 leads to the dispensing point. It is therefore located on the outlet side of the check valve CV.

[0066] At the opposite end of the valve body 1, the supply line 20 is connected to the valve body by means of a second connecting element 5 with an external thread 50 and to the valve body 1 by means of a second bushing 82 with an internal thread 83. The supply line 20 forms an inlet line of the check valve CV. The valve body 1 also has a circumferential beveled edge 10 in its interior, which forms a cone that now tapers in the direction of flow. The supply line 20 rests against this beveled edge 10 and is thus secured against rotation and fixed in the longitudinal direction.

[0067] As can be clearly seen in Figures 3 to 6, a return spring 7 is arranged between the piston 6 and the coupling element 3. It is inserted or held with one end into a receiving opening 620 of the piston 6 and with the other end into a receiving opening 36 of the coupling element 3. It extends centrally and in the direction of the piston axis 63, which can be seen in Figure 10.

[0068] In Figure 3, the check valve CV is shown in the closed state, and in Figure 5 in the open state. The direction of flow through the open valve is shown by arrows in Figure 5. A flowing fluid, preferably hydrogen, flows around the outer surface of the piston 6 and flows between the piston 6 and the inner wall of the valve body 1 through outlet channels 35 of the coupling element 3. The outlet channels 35 run, as can be clearly seen in Figures 3 and 5, obliquely, i.e. at an angle, to the piston axis 63. The outlet channels 35 open into a common chamber 38 which is connected to the lumen of the intermediate line 21, so that the fluid can flow out of the check valve CV.

[0069] Figures 6 to 10 show the piston 6 in detail. It is preferably made of a high-performance plastic, more preferably PEEK. The piston 6 seals in the sealing seat 11 of the valve body 1 without a sealing ring or other seal. The sealing seat 11 is preferably made of steel or another metal. Alternatively, it is made of another material that is harder than the material of the piston 6.

[0070] The piston 6 has a base body 60 with a first and a second end. The first end has an end piece 62 with a receiving opening 620 in the form of a blind bore. In this example, the end piece 62 is frustoconical and the receiving opening 620 is circular. Other shapes are possible. The receiving opening 620 serves to accommodate the return spring 7, as can be clearly seen in Figures 3 and 5. The opposite end face 600 is closed and preferably flat. This end is conical and tapers towards the free end face 600. This end face 600 and / or its adjacent conical region form the sealing area for closing the check valve CV. When the valve is closed, the piston 6 rests with this sealing area against the widening sealing seat 11. This can be clearly seen in Figures 3 and 4.

[0071] Ribs 61 protrude radially from the base body 60. They extend parallel to the piston axis 63. They preferably extend approximately over the entire length of the base body. In this example, five ribs 61 are present, matching the five outlet channels 35 of the coupling element 3. Between the ribs, the base body 60 forms the outer surfaces along which the fluid flows. The number of intermediate surfaces is thus preferably the same as the number of outlet channels 35. The outlet channels 35 are preferably aligned with the surfaces located between the ribs 61.

[0072] A different number of ribs 61 and exhaust ports 35 are also possible. There may also be a different number of ribs 61 compared to the exhaust ports 35.

[0073] The ribs 61 preferably extend to the inner wall of the valve body 1. The piston 6 can thus be guided along the piston axis 60 within the valve body 1. Depending on the embodiment, the piston 6 is arranged in the valve body 1 so as to be rotatable about its piston axis. In other embodiments, it is arranged in the valve body 1 in a rotationally secured manner. In one embodiment, the piston 6 is mounted in the valve body 1 with at least one rib 61.

[0074] Due to the selected sections, there is a gap between the ribs 61 of the piston 6 and the valve body 1 in Figures 3 to 5. However, in the section according to Figure 4, it can be seen in the lower area of ​​the piston 6 that it rests against the inner wall of the valve body 1.

[0075] The coupling element 3 is shown in detail in Figures 11 to 15. It is preferably made of metal or a high-performance plastic. It has a cylindrical base body 30, which has the external thread 31 and the adjoining flange 32 at one end. The internal thread 320 is arranged in the flange 32. At the opposite end, the base body 30 preferably has a step-shaped tapered region 33, followed by an end piece 34 with a smaller diameter. The outlet channels 35 are arranged in the base body 30 and / or in the tapered region, as can be clearly seen from a combination of Figures 14 and 3. A sealing ring 9 seals the coupling element 3 in the tapered region 33 against the valve body 1, as can be seen in Figure 3. This sealing ring 9 is preferably the only sealing ring and is located between two static components. In Figures 12 and 14, a vent opening 37 is present.It leads through the valve body 1 to the outside and enables, for example, an inspection of the sealing points.

[0076] If a fluid flows in the direction of flow, i.e., from left to right in Figures 3 and 5, through the supply line 20 into the check valve CV, the piston 6 is pushed to the right against the force of the return spring 7, and the valve opens. The fluid flows along the outer surface of the piston 6 to the outlet channels 35 and into the intermediate line 21. If the fluid pressure in this direction is lost, the check valve CV closes automatically thanks to the return spring 7.

[0077] However, if fluid pressure is applied to the valve in the opposite direction of flow before closing, i.e., if a fluid flows from right to left through the outlet channels 35 into the interior of the valve body 1, the pressure surge on the piston 6 is reduced thanks to the angled arrangement of the outlet channels 35. This is because the pressure is not applied, or only minimally, in a direction perpendicular to the piston. Thus, the piston 6 cannot impact the sealing seat with great force.

[0078] The closing movement of the piston is still gentle and dampened.

[0079] The check valve according to the invention can be used for high pressures and enables gentle closing even when the pressure is reversed.

[0080] LIST OF REFERENCE SYMBOLS

[0081] Valve body bevel edge 6 piston sealing seat 60 base body

[0082] 600 frontal area

[0083] Supply line 61 rib

[0084] Intermediate line 62 End piece dispensing line 620 Receptacle opening

[0085] 63 Piston axis

[0086] Coupling element base body 7 return spring external thread flange 80 first bushing

[0087] Internal thread 81 Internal thread bevel 82 Second bushing tapered area 83 Internal thread end piece

[0088] Outlet channel 9 sealing ring

[0089] Receiving opening Vent opening B1 first storage bank Chamber B2 second storage bank

[0090] HV1 first high pressure valve first connecting element HV2 second high pressure valve external thread CV1 first check valve

[0091] CV2 second check valve second connecting element CV check valve external thread

Claims

PATENT CLAIMS 1. A check valve, in particular of a hydrogen refueling system, wherein the check valve has an inlet and an outlet which define a flow direction extending from the inlet to the outlet, and wherein the check valve has a piston (6) which is arranged to be movable relative to the inlet and outlet for opening and closing the inlet of the check valve, wherein the piston (6) defines a piston axis (63) with a first end facing the inlet and a second end facing the outlet, wherein the piston (6) has an outer surface along which a fluid flowing through the check valve in the flow direction flows, and wherein the outlet has outlet channels (35) for allowing the fluid to flow out of the check valve, characterized in that all outlet channels (35) of the outlet run obliquely to the piston axis (63).

2. Check valve according to claim 1, wherein in an open position of the piston (6) only one channel is exposed which extends from the inlet to the outlet and which extends exclusively along the outer surface of the piston (6).

3. Check valve according to one of claims 1 or 2, wherein the piston (6) exclusively opens a channel between the inlet and outlet, which channel extends only along the outer surface of the piston (6).

4. Check valve according to one of claims 1 to 3, wherein the piston (6) has radially projecting ribs (61) on its circumference.

5. Check valve according to one of claims 1 to 4, wherein the check valve has a valve body (1), wherein the piston (6) is movably arranged in the valve body (1) and wherein the piston (6) is movable while guided by the valve body (1).

6. Check valve according to claims 4 and 5, wherein at least one of the Ribs (61) are mounted in the valve body (1).

7. Check valve according to one of claims 5 or 6, wherein the valve body (1) has a sealing seat (11) on which the piston (6) rests in the closed state of the check valve, and wherein the sealing seat (11) is made of metal.

8. A check valve according to any one of claims 4, 6 or 7, wherein the outer surface along which the fluid flows is arranged between the ribs (61).

9. Check valve according to one of claims 1 to 8, wherein the piston (6) seals without an elastomeric seal.

10. Check valve according to one of claims 1 to 9, wherein at least a part of the piston (6) is made of a plastic, preferably of PEEK.

11. Check valve according to claim 10, wherein the entire piston (6) is made of plastic, preferably PEEK.

12. Check valve according to one of claims 1 to 11, wherein a return spring (7) is provided which presses the piston (6) into a sealing seat (11) in order to close the check valve.

13. Check valve according to one of claims 1 to 12, wherein a coupling element (3) is provided which is fastened to a housing of the check valve, wherein the coupling element (3) has through openings which form the outlet channels (35).

14. Check valve according to claim 13, wherein the piston (6) is guided in the valve body (1) and is arranged at a distance from the coupling element (3).

15. Check valve according to claims 12 and one of claims 13 or 14, wherein the return spring (7) is arranged with a first end in the piston (6) and with a second end in the coupling element (3).

16. Check valve according to one of claims 12 or 15, wherein the return spring (7) is arranged in the piston (6) and wherein it is surrounded by the outlet channels (35).

17. Check valve according to claim 5 and one of claims 13 to 15, wherein the valve body (1) is the housing.

18. Check valve according to one of claims 1 to 17, wherein the same number of outlet channels (35) and surfaces between the ribs (21) are present.

19. A unit of a hydrogen refueling system with a first line for connecting a first storage bank (B1) to a dispensing line (22) and a second line for connecting a second storage bank (B2) to the same dispensing line (22), wherein a filling direction leads from the first storage bank (B1) and the second storage bank (B2) to the dispensing line (22), wherein a first high-pressure valve (HV1) and a first check valve (CV1) are arranged in the first line, wherein the first check valve (CV1) is arranged downstream of the first high-pressure valve (HV1) in the filling direction, wherein a second high-pressure valve (HV2) and a second check valve (CV2) are arranged in the second line, wherein the second check valve (CV2) is arranged downstream of the second high-pressure valve (HV2) in the filling direction, characterized inthat the first check valve (CV1) and the second check valve (CV2) are check valves according to one of claims 1 to 18.,

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