Check valve

Abstract

The present invention relates to a check valve, in particular of a hydrogenation installation, having an inlet and an outlet which define a flow direction which extends from the inlet to the outlet. The check valve has a piston (6) movably arranged relative to the inlet and the outlet to open and close the inlet of the check valve, where the piston (6) defines a piston axis (63) by means of a first end facing the inlet and a second end facing the outlet. The piston (6) has an outer surface along which a fluid flowing through the check valve in a flow direction flows. The outlet has outlet channels (35) in order to enable the fluid to flow outward from the check valve, all outlet channels (35) of the outlet running obliquely with respect to the piston axis (63). The check valve can be used for high pressure and allows soft closing even in the event of a reversal of the pressure action. The check valve is used in particular in hydrogen refueling stations.

Description

Technical Field

[0001] The present invention relates to a check valve, in particular to a check valve of a hydrogenation facility, and a unit of the hydrogenation facility. Background Art

[0002] A hydrogen filling facility, in particular a hydrogen filling station, has one or more pressure tanks in which liquid or compressed gaseous hydrogen is provided for filling motor vehicles or rail vehicles. Pressure tanks are also called depots or storage depots.

[0003] In order to completely fill the vehicle as quickly as possible, hydrogen is taken from a plurality of reservoirs in succession. The greater the degree of filling of the vehicle, the higher the pressure in the reservoir must be. Therefore, the pressure in the individual reservoirs is of different heights, which are usually 350 bar, 500 bar, 700 bar and 1000 bar. However, reservoirs with other pressures are also feasible.

[0004] In order to be able to fill the vehicle as quickly as possible, it is necessary to switch to a reservoir with a higher pressure as quickly as possible.

[0005] High-pressure valves, in particular pilot-controlled solenoid valves, enable fast switching times and thus also fast switching of the storage tanks. The switching times are between 10 ms and 200 ms. The check valve prevents hydrogen from flowing back from the filling line connected to the vehicle's hydrogen tank into the storage tank.

[0006] The rapid opening of the reservoir leads to high pressure shocks or pressure pulses in the pipeline of the reservoir. The high pressure shocks can damage the check valve of the reservoir connected downstream in the flow direction. In particular, the sealing element can move in the flow direction so that the check valve is no longer closed.

[0007] If during filling, a higher pressure level is switched to another storage tank, the check valve is also subjected to a high pressure shock or pressure pulse in the reverse flow direction. The pressure shock is caused by the pressure increase in the pipeline. The solenoid valve is usually closed more slowly than it opens. This results in that when the solenoid valve of the second storage tank or the subsequent storage tank is fully opened, the check valve of the first storage tank or the storage tank connected to the upstream is not fully closed. The pressure shock acting on the check valve closes the check valve with a relatively large force. The piston of the check valve is usually pressed into the sealing seat with a large force. This greatly reduces the service life of the check valve on the one hand. The sealing seat may even be damaged, so that the check valve is no longer optimally closed. This limits the maximum pressure that can really exist in the storage tank.

[0008] Therefore, the high pressure surges in the flow direction, in particular but also in the reverse flow direction, place high demands on the nonreturn valve and reduce its service life. This leads to high maintenance costs and can lead to failures of the filling system.

[0009] In the prior art, non-return valves are known in which a steel piston through which a fluid flows strikes an elastic or thermoplastic sealing element. Steel pistons are also known on which an elastic or thermoplastic sealing element is arranged. Under high pressure, such as is used, for example, in hydrogen filling stations, there is a risk that the sealing element may fly out or at least move.

[0010] Non-return valves with a steel piston that strikes a steel seat and through which the fluid flows have the disadvantage that they seal more poorly than soft seats with elastic or thermoplastic sealing elements.

[0011] DE 10 2016 014 312 A1 discloses a non-return valve having a piston made of PEEK (polyetheretherketone), through which an obliquely extending passage passes. The non-return valve is used in particular in piston pumps and compressors.

[0012] Furthermore, non-return valves are known, the piston of which is flowed around by the fluid. However, these non-return valves have no non-return protection, so that they are not suitable for pressures such as those present in hydrogenation plants. Summary of the invention

[0013] The object of the present invention is therefore to provide a non-return valve, in particular for a hydrogenation plant, which has a gentle closing behavior even when pressure is applied in the opposite direction and has the longest possible service life when subjected to stresses due to high pressure surges.

[0014] This object is achieved by a non-return valve having the features of claim 1 and a unit of a hydrogenation plant having the features of claim 19 .

[0015] The non-return valve according to the invention has an inlet and an outlet, which define a flow direction, which extends from the inlet to the outlet. The non-return valve has a piston which is movably arranged relative to the inlet and the outlet to open and close the inlet of the non-return valve. The piston defines a piston axis by means of a first end facing the inlet and a second end facing the outlet. The piston has an outer surface along which a fluid flowing through the non-return valve in the flow direction flows. The outlet has an outlet channel so that the fluid can flow outward from the non-return valve, wherein all outlet channels of the outlet extend obliquely relative to the piston axis, i.e. at an angle not equal to 0°.

[0016] Since the outlet channel extends obliquely to the piston axis, the fluid flowing into the check valve from the outlet side at high pressure does not exert high pressure pulses on the piston. Therefore, if the fluid flows in the reverse flow direction, that is, from the outlet side, the check valve still closes relatively softly.

[0017] When the piston is loaded with fluid in the flow direction, the piston is flowed around. The fluid flows along the outer surface of the piston. This can minimize the pressure pulses acting on the piston and reduce pressure losses. A large flow through the check valve is achieved.

[0018] Check valves are suitable for various applications, in particular for applications with high pressure pulses in the reverse flow direction. Check valves are particularly suitable for use in hydrogenation facilities, in particular in hydrogenation stations for motor vehicles. Check valves can be used in particular at pressures up to 1000 bar and higher. Due to the increased service life of the check valves, the maintenance intervals of the facilities, in particular hydrogenation facilities, are long and the maintenance costs are low. Failures of such facilities are reduced or avoided. Other fields of application are, for example, hydrogen tankers and electrolyzers for producing hydrogen.

[0019] Furthermore, the nonreturn valve according to the invention is suitable for retrofit installations since it is of relatively space-saving and simple design.

[0020] Preferably, the piston is completely circumvented, that is to say no portion of the fluid flows through the piston. Preferably, in the open position of the piston, only one channel is released, which extends from the inlet to the outlet and which extends only along the outer surface of the piston. Preferably, the piston opens only one channel between the inlet and the outlet, which extends along the outer surface of the piston. This optimizes the damping of the piston when the valve is opened and closed and achieves a high flow rate in the flow direction from the inlet to the outlet. In addition, the piston can be implemented robustly and thus with a long service life, because the piston is not penetrated by a channel that would weaken it.

[0021] Preferably, the piston can be moved in a guided manner. In a preferred embodiment, the piston has radially protruding ribs at its circumference, wherein the outer surface is preferably arranged between the ribs, along which the fluid flows. The ribs minimize eddies in the fluid flow. Preferably, the ribs guide the movement of the piston. In some embodiments, at least one of the ribs is supported in the valve body.

[0022] Preferably, the non-return valve has a valve body in which a piston is movably arranged, wherein the piston can be moved guided by the valve body. If ribs are present on the piston, they preferably extend to the inner wall of the valve body in order to guide the piston and conduct the flow. According to an embodiment, at least one of the ribs, preferably all of the ribs, is supported in the valve body.

[0023] Preferably, there are as many outlet channels as there are surfaces between the ribs. This optimizes the fluid flow along the piston.

[0024] Preferably, the valve body has a sealing seat, on which the piston rests in the closed state of the non-return valve, wherein the sealing seat is preferably made of metal. An elastic seal, such as an O-ring, is preferably present neither at the sealing seat nor at the piston. Preferably, the piston seals without an elastic seal.

[0025] In a preferred embodiment, at least a portion of the piston is made of plastic, in particular of high-performance plastic and preferably of PEEK. Preferably, the entire piston is made of plastic, in particular of high-performance plastic and preferably of PEEK. This improves the damping properties of the piston. In addition, the piston has a relatively low weight. The moving mass of the check valve is reduced. The opening and closing speed and the impact resistance are improved. An additional elastic sealing element between the piston and the sealing seat can be eliminated.

[0026] If the sealing seat is made of metal, the sealing effect is optimized when using a piston made of plastic, especially PEEK. High-performance plastics, especially PEEK, are resistant over a very large temperature range, both in the negative and positive ranges of ° C. As a result, the nonreturn valve is optimally suitable for permanent use with hydrogen.

[0027] Preferably, there is a coupling element which is fastened to the housing of the non-return valve, wherein the coupling element has a through-opening which forms the outlet channel. This allows the throughflow from the non-return valve through the outlet channel in the flow direction to be maximized. This is particularly optimal for hydrogenation plants, since the filling time can be minimized. Due to the outlet channel with a large diameter, the pressure loss is minimized. Preferably, the piston is guided in the valve body and is arranged spaced apart from the coupling element.

[0028] The coupling element can be designed, for example, as a hollow screw which can be screwed into or on the housing. This facilitates assembly.

[0029] Preferably, the valve body forms the housing of the non-return valve.

[0030] Preferably, a return spring is provided, which presses the piston into the sealing seat in order to close the nonreturn valve. Preferably, the return spring is arranged with a first end in the piston and with a second end in the coupling element. Preferably, the return spring is arranged in the piston, wherein the return spring is surrounded by the outlet channel. This is an extremely compact arrangement, which minimizes the size of the nonreturn valve.

[0031] The unit according to the invention of the hydrogenation facility has a first pipeline for connecting a first storage reservoir to a filling pipeline and a second pipeline for connecting a second storage reservoir to the same filling pipeline. The filling direction leads from the first storage reservoir and the second storage reservoir to the filling pipeline. A first high-pressure valve, in particular a solenoid valve controlled by a pilot valve, and a first check valve are arranged in the first pipeline, 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 solenoid valve controlled by a pilot valve, and a second check valve are arranged in the second pipeline, 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 already described above. The filling direction is preferably the flow direction through the check valve mentioned above.

[0032] Further embodiments are described in the dependent claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Preferred embodiments of the present invention are described below with reference to the accompanying drawings, which are only used for illustration and should not be interpreted as limiting. In the accompanying drawings:

[0034] Figure 1 a schematic diagram showing the units of a hydrogenation facility;

[0035] Figure 2 A perspective view showing a check valve with an inlet line and an outlet line according to the present invention;

[0036] Figure 3 Shown through the closed state according to Figure 2 The longitudinal section of the check valve;

[0037] Figure 4 Shown through the closed state according to Figure 2 Another longitudinal section of the check valve;

[0038] Figure 5 Shown through the open state according to Figure 2 The longitudinal section of the check valve;

[0039] Figure 6 Show according to Figure 2 A first perspective view of a piston of a check valve;

[0040] Figure 7 Show according to Figure 6 A first view of an end side of a piston;

[0041] Figure 8 Show according to Figure 6 A second stereoscopic view of the piston;

[0042] Fig. 9 Show according to Figure 6a second view of an end side of the piston;

[0043] Fig.10 Show according to Figure 6 A side view of a piston;

[0044] Fig.11 Show according to Figure 2 A first stereoscopic view of a coupling element of a check valve;

[0045] Fig.12 Show according to Fig.11 A first view of an end side of a coupling element;

[0046] Fig.13 Show according to Fig.11 A second stereoscopic view of a coupling element;

[0047] Fig.14 Show according to Fig.11 A second view of the end side of the coupling element;

[0048] Fig.15 Show according to Fig.11 Side view of the coupling element. DETAILED DESCRIPTION

[0049] exist Figure 1 A hydrogen filling station with two storage tanks B1, B2 for hydrogen is schematically shown in . Typically, there are three, four or more storage tanks B1, B2 per filling point.

[0050] The various hydrogen storage tanks B1, B2 have different pressures. The pressures are preferably 350 bar, 500 bar, 700 bar and 1000 bar. In the example described, the first storage tank B1 has a lower pressure than the second storage tank B2.

[0051] From each reservoir B1, B2, a respective supply line 20 leads via valves HV1, HV2, CV1, CV2 to an intermediate line 21 and subsequently to a common filling line 22, which leads to a filling point (not shown). This is the filling direction when filling a motor vehicle (also not shown) and the flow direction through the valves HV1, HV2, CV1, CV2. The supply line 20, the intermediate line 21 and the filling line 22 are preferably metal pipes. Preferably, they are rigid.

[0052] exist Figure 1 Not shown are cryogenic pumps or compressors for compressing hydrogen, which are connected to the reservoirs B1 , B2 , and filling points, also called filling columns, which are connected to the reservoirs B1 , B2 via filling lines 22 and at which the motor vehicle can be filled with hydrogen.

[0053] Each reservoir B1, B2 is associated with a high-pressure valve HV1, HV2, preferably a pilot-controlled solenoid valve. In the flow direction, a corresponding check valve CV1, CV2 is arranged downstream of the high-pressure valve HV1, HV2. When pressure is applied to the filling line 22 in the flow direction, the check valve CV1, CV2 opens and prevents fluid flow in the opposite direction, that is, prevents backflow toward the reservoir B1, B2.

[0054] When filling a motor vehicle, hydrogen is first taken from the reservoir at the lowest pressure, in the example described, from the first reservoir B1. For this purpose, the associated first high-pressure valve HV1 is opened, whereby the associated first non-return valve CV1 is also opened due to the pressure present in the flow direction of the fluid flow, here hydrogen. The second solenoid valve HV2 is closed, whereby the second non-return valve CV2 is also closed. The fluid, here hydrogen, flows from the first reservoir B1 via the supply line 20 and the intermediate line 21 to the filling line 22 and thus to the filling point.

[0055] When the pressure in the hydrogen tank of the motor vehicle increases, the pressure difference between the first storage reservoir B1 and the hydrogen tank decreases. In order to be able to refill further quickly, switch to the second storage reservoir B2 with a higher pressure. Therefore, the first high-pressure valve HV1 is closed and the second high-pressure valve HV2 is opened, so that the second check valve CV2 is also opened. Because the first solenoid valve HV1 and / or the first check valve CV1 closes more slowly than the opening of the other valves, the now increased pressure in the intermediate line 21 acts on the first check valve CV1, which is not yet completely closed. This pressure shock accelerates the closing element of the check valve CV1, which is usually a piston, so that the piston hits the sealing seat at high speed. As mentioned at the beginning, this can damage the check valve or at least greatly shorten the service life of the check valve.

[0056] exist Figures 2 to 5 An example of a check valve CV according to the present invention is shown in FIG. Figure 1 The non-return valves are used as first and second non-return valves CV1, CV2 in a device of . However, the non-return valves can also be used in other areas, in which good damping of the piston movement or at least a gentle piston movement in the flow direction and / or in the reverse flow direction is advantageous. The valve can also be used for other fluids and other applications.

[0057] The non-return valve CV has a valve body 1 which forms the housing of the non-return valve CV. The valve body 1 is preferably formed in one piece. Preferably, the valve body is made of metal, in particular of steel.

[0058] The valve body has an inner chamber, in which a piston 6 is arranged in a movable manner in the longitudinal direction of the valve body 1. The coupling element 3 is held at or in the valve body 1. In the example, the coupling element 3 is designed as a hollow screw and is screwed into the end of the valve body 1 located on the outlet side in the flow direction via an external thread 31. The coupling element 3 has a base 30 and a flange 32, wherein the flange 32 is preferably placed at the outer end side of the valve body 1. The coupling element 3 preferably has an internal thread 320 in the region of the flange 32. In the inner chamber of the coupling element 3, a circumferential bevel edge 321 is preferably formed, which forms a cone that tapers in the reverse flow direction.

[0059] The intermediate line 21 forms the outlet line of the non-return valve CV. The intermediate line is connected to the valve body 1 via a first connecting element 4 with an external thread 40 and a first sleeve 80 with an internal thread 81. In the example described, the intermediate line is connected to the coupling element 3 for this purpose. The intermediate line 21 is preferably located at the circumferential bevel edge 321, so that it is held fixedly against rotation and in the longitudinal direction.

[0060] As mentioned above, the intermediate line 21 leads to the filling point. Therefore, the intermediate line is arranged at the non-return valve CV on the outlet side.

[0061] 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 is connected to the valve body 1 by means of a second sleeve 82 with an internal thread 83. The supply line 20 forms the inlet line of the non-return valve CV. The valve body 1 also has a circumferential bevel 10 in the interior, which forms a cone that now tapers in the flow direction. The supply line 20 rests on the bevel 10 and is thus held fixedly against rotation and in the longitudinal direction.

[0062] As in Figures 3 to 6 It can be clearly seen that a return spring 7 is arranged between the piston 6 and the coupling element 3. The return spring is inserted into the receiving opening 620 of the piston 6 with one end and inserted into the receiving opening 36 of the coupling element 3 with the other end or is held in the receiving opening. The return spring extends centrally and toward the piston axis 63. Fig.10 The piston axis can be seen in FIG.

[0063] exist Figure 3 The non-return valve CV is shown in the closed state. Figure 5 The non-return valve CV is shown in the open state. Figure 5 The arrows in FIG. 1 indicate the flow direction through the open valve. The 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 the outlet channel 35 of the coupling element 3. Figure 3 and Figure 5 It can be clearly seen in FIG. 1 that the outlet channel 35 runs obliquely, ie at an angle, relative to the piston axis 63. The outlet channel 35 opens into a common chamber 38 which is connected to the interior of the intermediate line 21 so that the fluid can flow out of the non-return valve CV.

[0064] exist Figures 6 to 10 6 is shown in detail in FIG. The piston 6 is preferably made of high-performance plastic and more preferably of PEEK. The piston 6 seals in the sealing seat 11 of the valve body 1 without sealing rings or other seals. The sealing seat 11 is preferably made of steel or other metals. Alternatively, the sealing seat can be made of another material that is harder than the material of the piston 6.

[0065] The piston 6 has a base body 60 with a first end and a second end. The first end has an end piece 62 which has a receiving opening 620 in the form of a blind hole. In the present example, the end piece 62 is conical and the receiving opening 620 is circular. Other shapes are possible. The receiving opening 620 is used to receive the return spring 7, as in Figure 3 and Figure 5 The opposite end face 600 is closed and preferably flat. The end is conically shaped and tapers toward the free end face 600. The end face 600 and / or its adjacent conical area form a sealing area for closing the non-return valve CV. When the valve is closed, the piston 6 rests on the widened sealing seat 11 with the aid of the sealing area. This Figure 3 and Figure 4 It can be clearly seen in.

[0066] The ribs 61 protrude radially from the base body 60. The ribs extend parallel to the piston axis 63. Preferably, the ribs extend over almost the entire length of the base body. In the example described, there are five ribs 61, which match the five outlet channels 35 of the coupling element 3. The base body 60 forms an outer surface between the ribs, along which the fluid flows. Therefore, the number of surfaces between them is preferably the same as the number of outlet channels 35. Preferably, the outlet channels 35 are aligned with the surfaces between the ribs 61.

[0067] A different number of ribs 61 and outlet channels 35 is also possible. There can also be a different number of ribs 61 than outlet channels 35 .

[0068] The rib 61 preferably extends to the inner wall of the valve body 1. Thus, the piston 6 can be moved in the valve body 1 along the piston axis 60 in a guided manner. According to an embodiment, the piston 6 is arranged in the valve body 1 so as to be rotatable about its piston axis. In other embodiments, the piston is arranged in the valve body 1 so as to be prevented from rotating. In one embodiment, the piston 6 is supported in the valve body 1 by means of at least one rib 61.

[0069] Due to the selected cross section, Figures 3 to 5 There is a distance between the rib 61 of the piston 6 and the valve body 1. Figure 4 In the section of FIG. 1 , the lower region of the piston 6 can be seen, which bears against the inner wall of the valve body 1 .

[0070] exist Figures 11 to 15 3 shows the coupling element 3 in detail. The coupling element is preferably made of metal or high-performance plastic. The coupling element has a cylindrical base body 30, which has an external thread 31 and a flange 32 connected thereto at one end. An internal thread 320 is arranged in the flange 32. At the opposite end, the base body 30 preferably has a stepped tapered area 33, followed by an end piece 34 with a small diameter. The outlet channel 35 is arranged in the base body 30 and / or in the tapered area, such as by Fig.14 and Figure 3 The sealing ring 9 seals the coupling element 3 relative to the valve body 1 in the tapered area 33, as shown in FIG. Figure 3 The sealing ring 9 is preferably the only sealing ring and is located between two static components. Fig.12 and Fig.14 There is an exhaust port 37 in the valve body 1. The exhaust port leads to the outside through the valve body 1 and enables, for example, inspection of the sealing position.

[0071] If the fluid flows in the direction of Figure 3 and Figure 5 If the fluid flows from left to right through the supply line 20 into the check valve CV, the piston 6 is pressed 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 channel 35 and flows into the intermediate line 21. If the fluid pressure drops in the direction described, the check valve CV is automatically closed due to the return spring 7.

[0072] However, if the fluid pressure is applied to the valve in the opposite direction of the flow direction before closing, that is, when the fluid flows from right to left through the outlet channel 35 into the inner space of the valve body 1, the pressure impact on the piston 6 is reduced due to the inclined arrangement of the outlet channel 35. This is because there is no pressure loading or only minimal pressure loading in the vertical direction relative to the piston. Therefore, the piston 6 can not collide with the sealing seat with a large force. The closing movement of the piston is soft or damped as always.

[0073] The nonreturn valve according to the invention can be used for high pressures and enables gentle closing even in the event of a reversal of the pressure effect.

[0074] Reference numerals list

[0075] 1 Valve body

[0076] 10 Beveled Edges

[0077] 11 Sealing seat

[0078] 20 Supply pipeline

[0079] 21 Intermediate pipeline

[0080] 22 Filling pipeline

[0081] 3 Coupling elements

[0082] 30 Matrix

[0083] 31 external thread

[0084] 32 Flange

[0085] 320 Internal thread

[0086] 321 Bevel Edge

[0087] 33 Shrinking Area

[0088] 34 end parts

[0089] 35 Exit Channel

[0090] 36 accommodating openings

[0091] 37 Exhaust port

[0092] 38 chambers

[0093] 4First connecting element

[0094] 40 external thread

[0095] 5 Second connecting element

[0096] 50 external thread

[0097] 6 Piston

[0098] 60 base

[0099] 600 end face

[0100] 61 ribs

[0101] 62 end parts

[0102] 620 Accommodate opening

[0103] 63 piston axis

[0104] 7Return spring

[0105] 80 first sleeve

[0106] 81 internal thread

[0107] 82 Second sleeve

[0108] 83 internal thread

[0109] 9 Sealing ring

[0110] B1 First Storage

[0111] B2 Second Storage

[0112] HV1 First High Pressure Valve

[0113] HV2 Second High Pressure Valve

[0114] CV1 First check valve

[0115] CV2 Second check valve

[0116] CV Check Valves

Claims

1. A check valve, in particular a check valve for a hydrogenation facility, wherein the check valve has an inlet and an outlet, the inlet and the outlet defining a flow direction, the flow direction extending from the inlet to the outlet, and wherein the check valve has a piston (6) movably arranged relative to the inlet and the outlet to open and close the inlet of the check valve, wherein the piston (6) defines a piston axis (63) by means of a first end facing the inlet and a second end facing the outlet, The piston (6) has an outer surface along which the fluid flowing through the check valve in the flow direction flows, and wherein the outlet has an outlet passage (35) to enable the fluid to flow outward from the check valve, It is characterized in that All outlet channels (35) of the outlet run obliquely relative to the piston axis (63).

2. The non-return valve according to claim 1, wherein in the open position of the piston (6) only one channel is released, which channel extends from the inlet to the outlet and which channel extends only along the outer surface of the piston (6).

3. The non-return valve according to any one of claims 1 or 2, wherein the piston (6) opens only one passage between an inlet and an outlet, the passage extending only along the outer surface of the piston (6).

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

5. The check valve according to any 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) can be moved guided by the valve body (1).

6. Check valve according to claims 4 and 5, wherein at least one of the ribs (61) is supported in the valve body (1).

7. The check valve according to claim 5 , wherein the valve body ( 1 ) has a sealing seat ( 11 ), the piston ( 6 ) is seated on the sealing seat in the closed state of the check valve, and wherein the sealing seat ( 11 ) is made of metal.

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

9. The non-return valve according to any one of claims 1 to 8, wherein the piston (6) seals without an elastic seal.

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

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

12. The non-return valve according to claim 1, wherein a return spring (7) is present, which presses the piston (6) into a sealing seat (11) in order to close the non-return valve.

13. The check valve according to any one of claims 1 to 12, wherein a coupling element (3) is present, which is fastened to the housing of the check valve, wherein the coupling element (3) has a through-opening which forms the outlet channel (35). 14 . The non-return 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 . The non-return valve according to claim 12 and claim 13 , 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. The non-return valve according to any one of claims 12 or 15, wherein the return spring (7) is arranged in the piston (6), and wherein the return spring is surrounded by the outlet channel (35).

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

18. The non-return valve according to any one of claims 1 to 17, wherein there are an equal number of outlet channels (35) and surfaces between the ribs (21).

19. A unit of a hydrogenation facility, said unit comprising a first pipeline for connecting a first storage reservoir (B1) to a filling pipeline (22) and a second pipeline for connecting a second storage reservoir (B2) to the same filling pipeline (22), The filling direction leads from the first storage tank (B1) and the second storage tank (B2) to the filling pipeline (22), A first high-pressure valve (HV1) and a first check valve (CV1) are arranged in the first pipeline, wherein the first check valve (CV1) is arranged downstream of the first high-pressure valve (HV1) in the filling direction, A second high-pressure valve (HV2) and a second check valve (CV2) are arranged in the second pipeline, wherein the second check valve (CV2) is arranged downstream of the second high-pressure valve (HV2) in the filling direction, It is characterized in that The first check valve (CV1) and the second check valve (CV2) are check valves according to any one of claims 1 to 18.

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