Sealing structure suitable for low-temperature liquid hydrogen pump and low-temperature liquid hydrogen pump

Abstract

The invention belongs to a sealing structure and aims to solve the problem that an existing piston sealing structure used in liquid hydrogen filling is affected by the low-temperature and high-pressure environment. The sealing structure suitable for the low-temperature liquid hydrogen pump and the low-temperature liquid hydrogen pump comprise a piston rod body arranged in an inner cavity of a pump body, and a plurality of piston rings are installed on the outer wall of the sealing end of the piston rod body in the axial direction. An elastic piece is arranged between the piston ring and the outer wall of the sealing end, and the piston ring and the elastic piece form a radial sealing structure. Meanwhile, the radial sealing structure abuts against one axial end of the sealing groove, an elastic cushion piece is arranged between the radial sealing structure and the other axial end of the sealing groove, and the elastic cushion piece and the radial sealing structure form an axial sealing structure. The sealing structure is less affected by the low-temperature and high-pressure environment, the sealing performance is greatly improved, the service life can be effectively prolonged, and leakage is reduced.

Description

Technical Field

[0001] This application pertains to a sealing structure, specifically a sealing structure suitable for cryogenic liquid hydrogen pumps and a cryogenic liquid hydrogen pump. Background Technology

[0002] Liquid hydrogen is a high-energy, environmentally friendly cryogenic liquid fuel that plays a vital role in industries such as aviation, aerospace, and shipbuilding. However, the high cost of hydrogen has become one of the key issues restricting the development of the hydrogen energy industry. Among these, the refueling of liquid hydrogen is particularly important, and it is generally done using liquid hydrogen pumps. Most existing liquid hydrogen pumps are plunger pumps, with a piston seal structure between the piston head and the pump body to seal the liquid hydrogen. Existing piston seal structures typically include several annular grooves spaced apart on the outer surface of the piston head, with piston rings installed in each groove. Sealing and support are achieved through the contact and engagement between the outer surface of the piston rings and the inner wall of the pump body.

[0003] However, most annular grooves are semi-open annular structures, posing a risk of liquid hydrogen leakage at the piston ring opening. Furthermore, due to the low-temperature, high-pressure operating environment, the piston rings are subject to thermal expansion and contraction, causing the opening gap to widen and further reducing the sealing effect. Therefore, existing sealing structures have poor sealing performance, short service life, and are prone to liquid hydrogen leakage. Summary of the Invention

[0004] This application addresses the technical problem that the piston sealing structure used in existing liquid hydrogen refueling systems suffers from significantly reduced sealing performance due to the low-temperature and high-pressure environment, leading to short service life and easy leakage. The application provides a sealing structure and a cryogenic liquid hydrogen pump suitable for cryogenic liquid hydrogen pumps.

[0005] To achieve the above objectives, this application adopts the following technical solution: In a first aspect, this application proposes a sealing structure suitable for cryogenic liquid hydrogen pumps, including a piston rod disposed in the internal cavity of the pump body; The sealing end of the piston rod is columnar, and several sealing grooves are formed axially on the outer wall of the sealing end. A piston ring is installed in the sealing groove, and the outer wall of the piston ring extends to the outside of the sealing end. An elastic element is provided between the piston ring and the outer wall of the sealing end, and the piston ring and the elastic element form a radial sealing structure. The radial sealing structure abuts against one axial end of the sealing groove, and an elastic pad is provided between the radial sealing structure and the other axial end of the sealing groove. The elastic pad and the radial sealing structure form an axial sealing structure. A compression chamber is formed between the end face of the sealing end and the inlet of the pump body.

[0006] Furthermore, the sealing end includes multiple axially detachably connected assembly units; Each of the assembled units is provided with a set of radial sealing structures and a set of axial sealing structures.

[0007] Furthermore, it also includes several leakage liquid return channels installed in the pump body; The leaked liquid return channel is connected to the pump body's outlet and compression chamber.

[0008] Furthermore, the elastic element is a spring coil; the elastic pad is a spring washer.

[0009] Furthermore, a supplementary sealing groove is also provided on the outer wall of the sealing end; A supplementary piston ring is installed in the supplementary sealing groove, and the outer wall of the supplementary piston ring extends to the outside of the sealing end.

[0010] Furthermore, the width of the supplementary sealing groove is greater than the width of the sealing groove.

[0011] Secondly, this application proposes a cryogenic liquid hydrogen pump, including a pump body, on which a liquid inlet and a liquid outlet are provided; and also includes a piston rod disposed in the inner cavity of the pump body; The sealing end of the piston rod is columnar, and several sealing grooves are formed axially on the outer wall of the sealing end. A piston ring is installed in the sealing groove, and the outer wall of the piston ring extends to the outside of the sealing end. An elastic element is provided between the piston ring and the outer wall of the sealing end, and the piston ring and the elastic element form a radial sealing structure. The radial sealing structure abuts against one axial end of the sealing groove, and an elastic pad is provided between the radial sealing structure and the other axial end of the sealing groove. The elastic pad and the radial sealing structure form an axial sealing structure. A compression chamber is formed between the end face of the sealing end and the inlet of the pump body.

[0012] Furthermore, the sealing end includes multiple axially detachably connected assembly units; Each of the assembled units is provided with a set of radial sealing structures and a set of axial sealing structures.

[0013] Furthermore, the pump body is provided with several leakage liquid return channels; The leaked liquid return channel is connected to the pump body's outlet and compression chamber.

[0014] Furthermore, a supplementary sealing groove is also provided on the outer wall of the sealing end; A supplementary piston ring is installed in the supplementary sealing groove, and the outer wall of the supplementary piston ring extends to the outside of the sealing end.

[0015] Compared with the prior art, this application has the following beneficial effects: This application proposes a sealing structure suitable for cryogenic liquid hydrogen pumps, including a piston rod disposed within the pump body cavity. A plurality of piston rings are axially mounted on the outer wall of the sealing end of the piston rod. An elastic element is disposed between the piston rings and the outer wall of the sealing end, forming a radial sealing structure. Simultaneously, the radial sealing structure abuts against one axial end of a sealing groove, and an elastic gasket is disposed between the radial sealing structure and the other axial end of the sealing groove, forming an axial sealing structure. In conventional sealing systems, under cryogenic and high-pressure conditions, piston ring contraction leads to increased gaps at the opening, causing leakage of the liquid working fluid and significantly impacting the overall compression efficiency of the pump. In this application, the piston rings are installed within the sealing groove, employing a closed-ring assembly method to achieve a fully enclosed contact seal. The elastic element and elastic gasket simultaneously form both radial and axial sealing structures. In the radial direction, the elastic tension of the elastic element allows the piston rings to maintain tight contact with the pump body wall, achieving radial sealing and support effects, thus mitigating the impact of fluid leakage caused by piston ring contraction due to cryogenic temperatures. In the axial direction, the elastic gasket allows the piston ring to fit tightly against the sealing end, achieving an axial seal. Therefore, the sealing structure of this application is less affected by low-temperature and high-pressure environments, significantly improving sealing performance, effectively extending service life, and reducing leakage.

[0016] This application also proposes a cryogenic liquid hydrogen pump, including the sealing structure described above for cryogenic liquid hydrogen pumps, possessing all the advantages of the sealing structure described above for cryogenic liquid hydrogen pumps. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of one embodiment of the sealing structure applicable to a cryogenic liquid hydrogen pump according to this application; Figure 2 This is a schematic diagram of the piston rod in an embodiment of this application; Figure 3 This is a schematic diagram of the sealing end in an embodiment of this application.

[0019] Wherein: 1-Pump body, 2-Compression chamber, 3-Inlet, 4-Piston rod, 5-Leaking liquid return channel, 6-Sealing end, 7-Sealing unit assembly, 8-Assembly unit, 9-Elastic pad, 10-Piston ring, 11-Elastic element, 12-Supplemental sealing groove, 13-Supplemental piston ring. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0021] Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0022] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0023] In the description of the embodiments of this application, it should be noted that if terms such as "upper," "lower," "horizontal," or "inner" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of the invention is in use, they are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this application. In addition, terms such as "first" and "second" are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0024] Furthermore, the use of the term "horizontal" does not imply that the component must be absolutely horizontal, but rather that it can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0025] In the description of the embodiments of this application, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0026] Liquid hydrogen, a cryogenic liquid fuel with high energy density that produces only water upon combustion, is gradually becoming a key energy source for high-end industries such as aviation, aerospace, and shipbuilding. In aviation, liquid hydrogen is considered an ideal alternative fuel for future large passenger aircraft and heavy transport aircraft, significantly reducing carbon emissions in the aviation industry. In aerospace, liquid hydrogen is commonly used in the propulsion systems of launch vehicles, providing powerful thrust for launch. In shipbuilding, with increasingly stringent environmental requirements for ocean shipping, ships powered by liquid hydrogen are gradually entering the research and pilot stages, potentially solving the problem of traditional ship fuel pollution. However, the large-scale development of the hydrogen energy industry still faces many challenges, with the high cost of hydrogen being one of the core factors restricting its widespread adoption. In the entire chain of hydrogen storage, transportation, and use, the liquid hydrogen refueling process is particularly crucial, as refueling efficiency and safety directly affect the actual user experience and cost control of hydrogen energy applications. Currently, the industry commonly uses liquid hydrogen pumps for refueling, and the performance of these pumps directly determines the stability and economy of the refueling process.

[0027] Although liquid hydrogen pumps are indispensable in liquid hydrogen refueling, the cryogenic and high-pressure environment of liquid hydrogen poses a severe challenge to their operation in practical applications. Among these challenges, sealing issues have become a prominent bottleneck affecting pump performance and hydrogen costs. On the one hand, as a volatile, flammable, and explosive cryogenic fluid, liquid hydrogen leaks not only waste valuable fuel and directly increase hydrogen costs but also risk fires, explosions, and other safety accidents, posing serious threats to personnel and equipment. On the other hand, poor sealing performance leads to decreased pump efficiency, and frequent leaks require shutdowns for maintenance, increasing equipment maintenance costs and downtime losses, further exacerbating the problem of excessively high hydrogen costs. These issues collectively restrict the large-scale application of liquid hydrogen in aviation, aerospace, and shipbuilding, and also delay the development of the hydrogen energy industry.

[0028] To address the sealing issues of liquid hydrogen pumps, the industry currently widely employs plunger pump structures. The core sealing component of these pumps is a piston seal structure located between the piston head and the pump body. Specifically, this seal structure is designed with several annular grooves spaced apart on the outer surface of the piston head, with a piston ring installed in each groove. The sealing principle relies on the tight contact between the outer surface of the piston ring and the inner wall of the pump body, forming a physical seal that prevents liquid hydrogen leakage from the gap between the piston head and the pump body. Simultaneously, the piston ring also provides some support, ensuring smooth reciprocating movement of the piston head within the pump body. This piston ring-based sealing structure, due to its relatively simple design, low manufacturing cost, and ease of maintenance, has been successfully applied in traditional ambient temperature high-pressure fluid transfer pumps and has therefore been gradually adopted in the design of liquid hydrogen pumps, becoming the mainstream technical solution for solving the sealing problems of liquid hydrogen pumps.

[0029] However, existing piston ring-based sealing structures still have significant shortcomings under the cryogenic and high-pressure conditions of liquid hydrogen, making them unsuitable for practical applications. Firstly, to facilitate installation of the piston rings onto the piston rod, most currently used piston rings employ a semi-open ring structure. This inevitably creates a gap at the opening, which, given the small size and strong permeability of liquid hydrogen molecules, easily leads to leakage. Secondly, the cryogenic environment of liquid hydrogen causes the piston rings to shrink and deform, while the high-pressure environment during filling further compresses them. Under the combined effects of cryogenic and high-pressure conditions, the gap at the piston ring opening widens further, significantly reducing the sealing performance of the sealing surface formed by the outer ring of the piston ring and the pump body wall, exacerbating the leakage problem. This poor sealing performance not only continuously wastes liquid hydrogen and poses safety hazards, but also reduces the lubrication effect between the piston ring and the pump body wall due to leakage, accelerating wear and shortening the service life of the piston ring and even the entire liquid hydrogen pump, creating a vicious cycle. Therefore, existing technologies struggle to fundamentally solve the sealing problem of liquid hydrogen pumps and effectively alleviate the issue of excessively high hydrogen costs.

[0030] Based on the above, this application proposes a sealing structure and a cryogenic liquid hydrogen pump suitable for cryogenic liquid hydrogen pumps. The following is a detailed description of this application in conjunction with embodiments and accompanying drawings.

[0031] As one embodiment of the sealing structure applicable to a cryogenic liquid hydrogen pump according to this application, it may include a piston rod 4 disposed in the inner cavity of the pump body 1. The sealing end 6 of the piston rod 4 has a columnar structure, and a plurality of sealing grooves are formed axially on the outer wall of the sealing end 6. A piston ring 10 is installed in the sealing groove, and the outer wall of the piston ring 10 extends to the outside of the sealing end 6. An elastic member 11 is disposed between the piston ring 10 and the outer wall of the sealing end 6, and the piston ring 10 and the elastic member 11 form a radial sealing structure. The radial sealing structure abuts against one axial end of the sealing groove, and an elastic pad 9 is disposed between the radial sealing structure and the other axial end of the sealing groove, and the elastic pad 9 and the radial sealing structure form an axial sealing structure. A compression chamber 2 is formed between the end face of the sealing end 6 and the liquid inlet 3 of the pump body 1.

[0032] It should be noted that the piston rod 4 is the basic load-bearing component of the entire sealing structure, and its sealing end 6 is used to install various sealing elements. The sealing groove is used to accommodate the piston ring 10, the elastic element 11, and the elastic pad 9, which serve to position and limit these components. The elastic element 11 is located between the piston ring 10 and the outer wall of the sealing end 6. The piston ring 10 is in direct contact with the inner wall of the pump body 1. The elastic element 11 provides radial force to the piston ring 10, ensuring tight contact between the piston ring 10 and the inner wall of the pump body 1. The radial sealing structure, through the cooperation of the piston ring 10 and the elastic element 11, prevents liquid hydrogen from leaking radially. The elastic pad 9 provides elastic force in the axial direction, forming an axial seal with the radial sealing structure to prevent liquid hydrogen from leaking axially. The compression chamber 2 is the space where liquid hydrogen is compressed and transported.

[0033] When the piston rod 4 retracts, the volume of the compression chamber 2 increases, and liquid hydrogen enters from the inlet 3; when the piston rod 4 extends, the volume of the compression chamber 2 decreases, and the liquid hydrogen is compressed and discharged. During this process, the sealing structure prevents liquid hydrogen from leaking through the gap between the piston rod 4 and the pump body 1 during compression and transportation, ensuring the efficient and safe operation of the liquid hydrogen pump. This application significantly improves the sealing performance of the cryogenic liquid hydrogen pump through dual protection of radial and axial seals. In the radial direction, the elastic element 11 continuously applies pressure to the piston ring 10. Even if the piston ring 10 shrinks due to cold in cryogenic environments, the elastic force of the elastic element 11 can compensate for its deformation, reducing the opening gap and effectively preventing radial leakage of liquid hydrogen. In the axial direction, the elastic pad 9 adapts to the axial movement of the piston rod 4 and dimensional fluctuations caused by temperature changes, forming a reliable axial sealing barrier and further reducing the risk of leakage. The synergistic effect of the dual sealing structure not only extends the service life of sealing components such as piston ring 10 and reduces maintenance costs, but also reduces liquid hydrogen waste and improves the operating efficiency of liquid hydrogen pumps. This alleviates the problem of excessively high hydrogen costs to a certain extent and provides technical support for the large-scale application of hydrogen energy in aviation, aerospace, and shipbuilding industries.

[0034] Based on the aforementioned sealing structure suitable for cryogenic liquid hydrogen pumps, this application also proposes a cryogenic liquid hydrogen pump, including a pump body 1 and a piston rod 4 disposed in the inner cavity of the pump body 1. The pump body 1 has an inlet 3 and an outlet. The specific structure of the piston rod 4 can adopt the aforementioned structure.

[0035] like Figure 1 The diagram shown is a schematic representation of one embodiment of the sealing structure applicable to a cryogenic liquid hydrogen pump according to this application. Figure 2 The diagram shown is a schematic representation of the piston rod 4 in this embodiment. Figure 3 The diagram shown is a schematic of the sealing end 6 in this embodiment.

[0036] In some embodiments of this application, the sealing end 6 includes multiple axially detachably connected assembly units 8, each assembly unit 8 having a set of radial sealing structures and a set of axial sealing structures. In this embodiment, the sealing end 6 is designed as a modular, detachable structure. First, the sealing reliability is significantly improved; multiple assembly units 8 form a multi-stage seal. Even if a slight gap appears in the sealing component of one assembly unit 8 due to low-temperature wear or contraction, subsequent assembly units 8 can still prevent further leakage of liquid hydrogen. Second, maintenance costs are significantly reduced; if one assembly unit 8 in the sealing end 6 is damaged, it is not necessary to disassemble and replace all assembly units 8, improving efficiency and saving costs. Furthermore, the flexibility of use is greatly improved. When improved sealing performance is required, it is not necessary to redesign the entire sealing end 6; only a few sets of assembly units 8 need to be added, improving applicability and the convenience of subsequent upgrades.

[0037] In this embodiment, several leakage liquid return channels 5 are also provided inside the pump body 1, which are connected to the outlet and compression chamber 2 of the pump body 1. These leakage liquid return channels 5 are evenly distributed within the pump body 1. During pump operation, under the reciprocating motion of the piston rod 4, liquid hydrogen enters the compression chamber 2 from the inlet 3 for pressurization, and then exits from the outlet. A small amount of leaked liquid flows axially along the inner wall of the pump body 1 from the compression chamber 2 towards the tail of the piston rod 4. Upon reaching the inlet of the leakage liquid return channel 5, it flows into the channel under pressure difference and exits from the outlet. In the next cycle of piston rod 4 reciprocating motion, the liquid is drawn into the compression chamber 2 through the inlet 3 for repressurization. On one hand, the leakage liquid return channels 5 on the inner wall of the pump body 1 serve as a compensation mechanism, reducing leakage losses during pump operation and improving the pump's volumetric efficiency. On the other hand, the compression heat generated during the reciprocating motion of the piston rod 4 and the frictional heat generated between the piston and the pump body 1 will exacerbate the vaporization phenomenon during the compression process of liquid hydrogen, leading to unstable operation of the pump body 1 during the compression process. This application provides uniformly distributed, narrow leakage liquid return channels 5 on the inner wall of the pump body 1, allowing the leaking liquid hydrogen to fully exchange heat with the compression chamber 2 along the inner side of the leakage liquid return channels 5, and to fully exchange heat with the low-temperature liquid hydrogen that does not flow into the compression chamber 2 on the outer side. This effectively cools the temperature inside the compression chamber 2, reduces the generation of gas during the pressurization process, and makes the pump body 1 operate more smoothly.

[0038] In this embodiment, a supplementary sealing groove 12 is also provided on the outer wall of the sealing end 6. A supplementary piston ring 1310 is installed in the supplementary sealing groove 12, and the outer wall of the supplementary piston ring 1310 extends to the outside of the sealing end 6. The width of the supplementary sealing groove 12 is greater than the width of the sealing groove.

[0039] In the radial direction, the outer surface of the elastic element 11 contacts the inner surface of the piston ring 10. The elastic tension of the elastic element 11 ensures that the outer surface of the piston ring 10 is in close contact with the inner wall of the pump body 1, achieving radial sealing and support. Compared to traditional piston sealing structures, this reduces the impact of fluid leakage caused by the shrinkage of the piston ring 10 due to low temperatures. In the axial direction, one side of the elastic pad 9 contacts the end face of the piston ring 10, and the other side contacts the sidewall of the sealing groove. The elastic tension of the elastic pad 9 ensures that the piston ring 10 is tightly pressed against the stepped surface of the sealing groove sidewall, achieving axial sealing. Compared to traditional piston sealing structures, the piston ring 10 in this application is a closed annular structure, avoiding fluid leakage at the opening of the piston ring 10. Furthermore, the elastic pad 9 also serves as a positioning element for the detachable connection between the assembled units 8.

[0040] It should be noted that the elastic element 11 can be a spring ring, the elastic pad 9 can be a spring washer, and the elastic element 11 and the elastic pad 9 can also be other elastic components.

[0041] This application serves the nation's major energy strategy. Against the backdrop of vigorous development of hydrogen energy, cryogenic hydrogen storage technology needs to be adapted to energy equipment. Similarly, in the field of cryogenic reciprocating pumps, there is a need for component and structural designs suitable for cryogenic operating conditions. Under normal conditions, the sealing system, when subjected to cryogenic and high-pressure conditions, experiences increased gaps at the opening due to the contraction of the piston ring 10, leading to liquid leakage and significantly impacting the overall compression efficiency of the pump. From a structural perspective, this application utilizes a closed piston ring 10 in conjunction with an assembled sealing end 6 for a fully enclosed contact seal. It also employs a structural compensation mechanism—a leakage liquid return channel 5 on the inner wall of the pump body 1—to mitigate the impact of the cryogenic and high-pressure environment on the working state of the pump body 1's sealing structure. This allows the leaked liquid hydrogen to flow back to the inlet valve and re-enter the compression chamber 2 for secondary compression, reducing volumetric efficiency loss, improving compression efficiency, enhancing the overall operating efficiency of the cryogenic reciprocating pump, and ensuring safe, efficient, and stable operation during the compression process.

[0042] The above are merely preferred embodiments of this application and are not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A sealing structure suitable for cryogenic liquid hydrogen pumps, characterized in that: Includes a piston rod (4) disposed in the inner cavity of the pump body (1); The sealing end (6) of the piston rod body (4) has a columnar structure, and a plurality of sealing grooves are provided on the outer wall of the sealing end (6) along the axial direction; a piston ring (10) is installed in the sealing groove, and the outer wall of the piston ring (10) extends to the outside of the sealing end (6); an elastic element (11) is provided between the piston ring (10) and the outer wall of the sealing end (6), and the piston ring (10) and the elastic element (11) form a radial sealing structure; the radial sealing structure abuts against one axial end of the sealing groove, and an elastic pad (9) is provided between the radial sealing structure and the other axial end of the sealing groove, and the elastic pad (9) and the radial sealing structure form an axial sealing structure; A compression chamber (2) is formed between the end face of the sealing end (6) and the liquid inlet (3) of the pump body (1).

2. The sealing structure suitable for cryogenic liquid hydrogen pumps according to claim 1, characterized in that: The sealing end (6) includes multiple axially detachably connected assembly units (8); Each of the assembled units (8) is provided with a set of radial sealing structures and a set of axial sealing structures.

3. A sealing structure suitable for cryogenic liquid hydrogen pumps according to claim 1 or 2, characterized in that: It also includes several leakage liquid return channels (5) installed inside the pump body (1); The leaked liquid return channel (5) is connected to the outlet of the pump body (1) and the compression chamber (2).

4. The sealing structure suitable for a cryogenic liquid hydrogen pump according to claim 3, characterized in that: The elastic element (11) is a spring coil; the elastic pad (9) is a spring washer.

5. The sealing structure suitable for a cryogenic liquid hydrogen pump according to claim 3, characterized in that: A supplementary sealing groove (12) is also provided on the outer wall of the sealing end (6); A supplementary piston ring (13)(10) is installed in the supplementary sealing groove (12), and the outer wall of the supplementary piston ring (13)(10) extends to the outside of the sealing end (6).

6. The sealing structure suitable for a cryogenic liquid hydrogen pump according to claim 5, characterized in that: The width of the supplementary sealing groove (12) is greater than the width of the sealing groove.

7. A cryogenic liquid hydrogen pump, comprising a pump body (1), wherein the pump body (1) is provided with an inlet (3) and an outlet; characterized in that: It also includes a piston rod (4) disposed in the inner cavity of the pump body (1); The sealing end (6) of the piston rod body (4) has a columnar structure, and a plurality of sealing grooves are provided on the outer wall of the sealing end (6) along the axial direction; a piston ring (10) is installed in the sealing groove, and the outer wall of the piston ring (10) extends to the outside of the sealing end (6); an elastic element (11) is provided between the piston ring (10) and the outer wall of the sealing end (6), and the piston ring (10) and the elastic element (11) form a radial sealing structure; the radial sealing structure abuts against one axial end of the sealing groove, and an elastic pad (9) is provided between the radial sealing structure and the other axial end of the sealing groove, and the elastic pad (9) and the radial sealing structure form an axial sealing structure; A compression chamber (2) is formed between the end face of the sealing end (6) and the liquid inlet (3) of the pump body (1).

8. A cryogenic liquid hydrogen pump according to claim 7, characterized in that: The sealing end (6) includes multiple axially detachably connected assembly units (8); Each of the assembled units (8) is provided with a set of radial sealing structures and a set of axial sealing structures.

9. A cryogenic liquid hydrogen pump according to claim 7 or 8, characterized in that: The pump body (1) is provided with several leakage liquid return channels (5); The leaked liquid return channel (5) is connected to the outlet of the pump body (1) and the compression chamber (2).

10. A cryogenic liquid hydrogen pump according to claim 9, characterized in that: A supplementary sealing groove (12) is also provided on the outer wall of the sealing end (6); A supplementary piston ring (13)(10) is installed in the supplementary sealing groove (12), and the outer wall of the supplementary piston ring (13)(10) extends to the outside of the sealing end (6).

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