Bidirectional piston type hydrogen compressor cylinder structure and hydrogen compressor

Abstract

The application discloses a bidirectional piston type hydrogen compressor cylinder structure and a hydrogen compressor, and relates to the technical field of hydrogen compressors. The hydrogen compressor comprises a cylinder structure, and the cylinder structure comprises a cylinder barrel. One end of the cylinder barrel is provided with a cylinder cover, and the other end is provided with a piston rod base. A cylinder sleeve is lined in a cylinder sleeve hole of the cylinder barrel. One end of the cylinder sleeve is supported on the piston rod base, and the other end of the cylinder sleeve is provided with a sealing assembly. The sealing assembly comprises a main sealing ring arranged in an interspace between the cylinder barrel and the cylinder cover. The main sealing ring serves as an axial sealing piece in the interspace. The main sealing ring and the cylinder sleeve are arranged on a constant-diameter section of the cylinder sleeve hole. The inner end surface of the main sealing ring is attached to the outer end surface of the cylinder sleeve. The corner positions on the inner and outer sides of the inner end surface of the main sealing ring are provided with rounded surfaces. The structure design adopted in the scheme can effectively reduce the failure rate of the hydrogen compressor by guaranteeing the reliability of internal parts.

Description

Technical Field

[0001] This invention relates to the field of hydrogen compressor technology, and in particular to a bidirectional reciprocating hydrogen compressor cylinder structure and a hydrogen compressor. Background Technology

[0002] Hydrogen, as a clean energy carrier and an important industrial raw material, requires efficient and safe compression, storage, and transportation, which are crucial links in the hydrogen energy industry chain. Piston compressors, due to their high compression efficiency and wide pressure range, are widely used in hydrogen pressurization applications. However, the unique physicochemical properties of hydrogen (small molecular weight, low density, strong diffusivity, and wide explosion limits) place far higher demands on the sealing reliability and operational safety of compressors compared to compressors for other gases such as air.

[0003] In the operation of a hydrogen compressor, the cylinder is the compression site. On the one hand, the properties of hydrogen make it highly susceptible to leakage at this location. To avoid potential safety hazards, the sealing design of the cylinder is crucial. On the other hand, hydrogen heats up significantly during pressurization. To improve cylinder wear resistance, a cylinder liner can be installed inside the cylinder barrel. To balance cost and casting performance, the cylinder barrel is often made of cast iron (with a cooling chamber integrally formed with the cylinder barrel on its inner wall), while the cylinder liner is made of alloy material. Due to the difference in thermal expansion coefficients between the cylinder barrel and the cylinder liner, the axial expansion of the cylinder liner is usually greater than that of the cylinder barrel after the cylinder barrel heats up.

[0004] As a design of an existing hydrogen compressor cylinder block structure (a bidirectional piston cylinder block structure with inlet and exhaust ports on both sides), such as Figure 1 and Figure 2 As shown, the cylinder block includes a cylinder barrel 2, a cylinder liner 8, and a cylinder head 9 and a piston rod seat 4 respectively installed at different ends of the cylinder barrel 2. An intake and exhaust gas passage assembly 1 is installed on the cylinder barrel 2. A boss is provided at the left end of the cylinder liner 8, and the cylinder liner 8 is clamped between the inner wall of the cylinder head 9 and the stepped surface of the cylinder barrel 2 through the boss. A gap 6 is provided between the right end of the cylinder liner 8 and the piston rod seat 4 to allow the cylinder liner 8 to expand and contract axially relative to the cylinder barrel 2. Furthermore, to solve the sealing problem, sealing structures 10 are provided at both ends of the cylinder barrel 2. The sealing structure 10 includes a sealing ring 3 and an O-ring 5. O-rings 5 ​​are provided between the cylinder head 9 and the cylinder liner 8, and between the piston rod seat 4 and the cylinder barrel 2. Sealing rings 3 are provided between the cylinder head 9 and the cylinder barrel 2, and between the piston rod seat and the cylinder barrel 2. The O-rings 5 ​​are used to prevent hydrogen leakage along the axial direction of the cylinder block, and the sealing rings 3 are used to prevent hydrogen leakage along the radial direction of the cylinder block.

[0005] Hydrogen compressors are core equipment used to increase hydrogen pressure and meet hydrogen transportation, storage, or process requirements. The bidirectional reciprocating hydrogen compressor is the mainstream implementation of hydrogen compressors. Its difference from the traditional unidirectional reciprocating compressor lies in the fact that a unidirectional reciprocating compressor only draws in gas during one stroke (the first direction of linear reciprocating motion) and exhausts gas during the other stroke (the second direction of linear reciprocating motion, opposite to the first direction). In contrast, the bidirectional reciprocating hydrogen compressor has inlet / exhaust ports at both ends of the cylinder. During the piston's linear reciprocating motion along the cylinder, both directions (the first and second directions) involve both intake and exhaust. This structural design not only improves gas compression efficiency through bidirectional piston work but also significantly optimizes compressor vibration during hydrogen compression.

[0006] Further development of reciprocating hydrogen compressor technology can effectively enhance its pivotal role in the development of the hydrogen economy. Summary of the Invention

[0007] In response to the aforementioned issues concerning the further development of reciprocating hydrogen compressor technology, this invention provides a bidirectional reciprocating hydrogen compressor cylinder structure and a hydrogen compressor. The structural design adopted in this solution can effectively reduce the failure rate of the hydrogen compressor by ensuring the reliability of its internal components.

[0008] To address the aforementioned problems, the present invention provides a bidirectional reciprocating hydrogen compressor cylinder structure and hydrogen compressor that solve the problems through the following technical points: The bidirectional reciprocating hydrogen compressor cylinder structure includes a cylinder barrel, one end of which is provided with a cylinder head, and the other end of which is provided with a piston rod seat. A cylinder liner is lined in the cylinder liner bore of the cylinder barrel. The inner end of the cylinder head extends into the cylinder liner and provides radial support for the cylinder liner. One end of the cylinder liner is supported on the inner end face of the piston rod seat, and the other end of the cylinder liner is provided with a sealing component.

[0009] The sealing assembly includes a main sealing ring disposed in the cavity between the cylinder barrel and the cylinder head, the main sealing ring serving as an axial seal in the cavity: the outer side of the main sealing ring is supported and pressed against the cylinder barrel bore wall, and the inner side of the main sealing ring is supported and pressed against the cylinder head end plate.

[0010] Both the main sealing ring and the cylinder liner are mounted on the equal-diameter section of the cylinder liner bore. The inner end face of the main sealing ring is in contact with the outer end face of the cylinder liner. The corner positions of the inner and outer sides of the inner end face of the main sealing ring are provided with rounded surfaces.

[0011] In this solution, the cylinder body is also referred to as a cylinder, which is used to provide the compression chamber of the compressor. The compression chamber is specifically located inside the cylinder liner. When used in a compressor, a piston ring is fitted inside the cylinder liner. The piston rod connected to the piston ring extends to the outside of the piston rod seat through a channel on the piston rod seat. The other end of the piston rod is connected to the drive unit. Depending on the specific design of the compressor, the power unit can be a drive motor or a hydraulic drive system, etc.

[0012] Unlike existing technologies, this solution aims to address the following issues: Figure 1 In the provided cylinder block structure, to accommodate the different thermal deformation of the cylinder liner compared to the cylinder barrel, existing methods include setting a gap between the cylinder liner and the piston rod seat. This gap serves as space to accommodate the cylinder liner when it elongates relative to the cylinder barrel. While this gap solves the problem of cylinder liner thermal deformation, depending on the deformation of the cylinder liner at different compressor temperatures, when this gap exists, the positional constraint of the cylinder liner in the cylinder barrel axial direction relies solely on the end of the cylinder liner with the boss (the cylinder liner only has a fixed support point at the cylinder head end). In this structural form, during use, the axial force from the piston rings on the cylinder liner can easily cause the cylinder liner to break at the boss connection point. Even after breakage, the cylinder liner may axially move and rotate within the cylinder barrel along with the piston rings. When the cylinder liner undergoes excessive deformation and the contact force with the piston rod seat is too large, the axial elongation of the cylinder liner is restricted, which may seriously affect the relationship between the piston rings and the cylinder. The aforementioned problems, particularly regarding the fit quality of the cylinder liner, pose serious threats to the reliability of the compressor. To address these issues, a cylinder structure is proposed where the main sealing ring is located at the end of the cylinder liner's outer end face. Specifically, the inner end of the cylinder liner is supported on the inner end face of the piston rod seat, while the other end is supported on the cylinder head via the main sealing ring. This structure provides axial constraint to both ends of the cylinder liner, stabilizing its position within the cylinder barrel and avoiding the potential breakage at the connection point of the boss on the cylinder liner. Furthermore, since the end structure of the cylinder liner's outer end face is a flexible main sealing ring, when the cylinder liner undergoes axial thermal deformation, it expands and contracts relative to the cylinder barrel on its outer end face to accommodate the differentiated thermal deformation of the cylinder barrel and cylinder liner. This prevents the axial elongation of the cylinder liner from being restricted, which could severely affect the fit quality between the piston ring and the cylinder liner.

[0013] Furthermore, for a bidirectional reciprocating hydrogen compressor, the existing design includes: a group of air holes on both sides of the cylinder liner; each air hole group on each end of the cylinder liner includes an inlet hole and an outlet hole; the inlet holes at both ends of the cylinder liner are connected to the air passage assembly on the cylinder barrel for connecting the intake air passage; and the outlet holes at both ends of the cylinder liner are connected to the air passage assembly on the cylinder barrel for connecting the exhaust air passage. Under this structural design, the mating surface between the outer side of the cylinder liner and the cylinder barrel is defined as the second mating surface, and the mating surface between the inner side of the cylinder liner and the cylinder head is defined as the first mating surface. When the piston ring moves towards the piston rod seat, the piston rod seat side is the compression side, and the cylinder head side is the intake side. At this time, under the pressure difference, the physical properties of hydrogen, and the mating relationship between the cylinder liner, cylinder barrel, and cylinder head, the gradually increasing pressure on the compression side may cause hydrogen to leak through the second mating surface towards the main sealing ring. Similarly, when the piston ring moves towards the cylinder head, the piston rod seat side is the intake side, and the cylinder head side is the compression side. At this time, the gradually increasing pressure on the compression side may cause hydrogen to leak through the second mating surface towards the main sealing ring. To prevent leakage towards the main sealing ring, this design places both the main sealing ring and the cylinder liner on equal-diameter sections of the cylinder liner bore. Rounded surfaces are positioned at the corners of the inner and outer sides of the main sealing ring's inner end face. These rounded surfaces form cavities outside the first and second mating surfaces on the outer end face of the cylinder liner. When hydrogen leaks through the second mating surface, the cavity formed by the rounded surface at the inner corner of the main sealing ring's inner end face prevents the main sealing ring from being partially squeezed into the first mating surface. Similarly, when hydrogen leaks through the first mating surface, the cavity formed by the rounded surface at the outer corner of the main sealing ring's inner end face prevents the main sealing ring from being partially squeezed into the second mating surface. Therefore, this main sealing ring structure design and its placement within the cylinder liner bore effectively prevent premature crack formation and failure due to the main sealing ring being squeezed into the first and second mating surfaces towards the cylinder liner, thus extending the lifespan of the main sealing ring.

[0014] As those skilled in the art will recognize, the equal-diameter section refers to a section on the cylinder liner bore with the same inner diameter at all axial positions. In specific implementations, the cylinder liner bore can be an equal-diameter bore. The above-mentioned rounded corner positions are designed to make the outer surface of the main sealing ring smooth, thus preventing localized stress concentration when the main sealing ring is deformed under pressure. This prevents premature cracking of the main sealing ring and subsequent crack propagation during use, which would affect the sealing performance and lifespan of the main sealing ring. Replacing the rounded surface with a chamfered surface also prevents the main sealing ring from being partially squeezed into the first and second mating surfaces towards the cylinder liner side. Those skilled in the art should consider such a replacement as an equivalent technical solution.

[0015] In a specific application, the cylinder liner is a regular cylindrical structure with the same inner and outer diameters at all positions along the axial direction. To achieve anti-rotation constraint between the cylinder liner and the cylinder barrel and to reduce leakage between the cylinder liner and the cylinder barrel, the cylinder liner and the cylinder liner bore are interference-fitted (as those skilled in the art, limited by processing quality and differentiated radial deformation at different positions of the cylinder liner and the cylinder liner bore, such a fit still cannot eliminate axial hydrogen leakage occurring at the second mating surface). The outer hole section on the outer end face of the cylinder liner bore and the end platform extending into the stepped hole on the cylinder head form the cavity. This cavity provides installation space for installing sealing components. The main sealing ring is an elastic sealing ring, preferably a PTFE composite elastic sealing ring, a PEEK composite material sealing ring, a perfluoroether rubber O-ring sealing ring, etc., which have strong pressure bearing capacity and are resistant to hydrogen permeation. The spring is a disc spring assembly or a corrugated spring, preferably a disc spring assembly that can relatively stably maintain the sealing pressure of the main sealing ring. The above main sealing ring selection is suitable for hydrogen compressors with exhaust pressure less than 100 MPa. When the exhaust pressure of the hydrogen compressor exceeds 100 MPa, the main sealing ring should preferably adopt a structure in which an elastic material is wrapped around the outer periphery of a metal elastic skeleton. For example, the metal elastic skeleton can be a ring-shaped helical spring made of nickel-based alloy. The elastic material wrapping the metal elastic skeleton is used to form a soft wrapping layer to fill the micro gaps on the sealing surface. When the outer end face of the main sealing ring is directly supported on the cylinder head, the elastic material can be a soft metal, such as pure silver or pure copper (to protect the elastic material, the surface roughness of the sealing mating surfaces on the inner and outer sides of the main sealing ring should preferably be set to Ra0.1μm~Ra0.15μm). When the outer end face of the main sealing ring is floatingly supported on the cylinder head by a spring, the elastic material is preferably PTFE material to form an elastic layer with excellent tear resistance (the surface roughness of the sealing mating surfaces on the inner and outer sides of the main sealing ring should preferably be set to less than Ra0.2μm).

[0016] A further technical solution for the cylinder block structure of the bidirectional reciprocating hydrogen compressor is as follows:

[0017] The sealing assembly also includes a spring disposed in the cavity, the spring being disposed on the side of the main sealing ring away from the cylinder liner, the spring serving as an elastic support structure providing axial support to the main sealing ring.

[0018] In the above scheme, the spring is used to form elastic support for the main sealing ring, aiming to address the following issues: When the cylinder liner and cylinder barrel undergo differentiated axial deformation, the spring undergoes elastic deformation with different deformation amounts under the cylinder liner thrust / deformation amount. This not only provides deformation space for the axial expansion and contraction of the cylinder liner relative to the cylinder barrel, but also stabilizes the heating position of the cylinder liner within the cylinder barrel. Simultaneously, the configuration of the main sealing ring and spring in this structure forms a hydrogen isolation barrier serving the spring. For example, in hydrogen refueling station applications, high-pressure compression (e.g., increasing from 25 MPa to 90 MPa) may cause the compressor exhaust temperature to exceed 200°C; in the design of portable compressors, to achieve compressor miniaturization and compact design, a simpler cooling system (including cylinder block cooling module and interstage cooling) is needed. The module may also cause the compressor exhaust temperature to exceed 200°C; when the cooling system or exhaust valve fails, the compressor exhaust temperature may even exceed 200°C. In the above scenarios, the spring, which is directly exposed to hydrogen and acts as an elastic element, will gradually lose its function due to hydrogen embrittlement and hydrogen corrosion under high temperature and high hydrogen partial pressure (especially at the spring end and in the crack defect area). This will cause its force-displacement characteristics to drift or even lose elasticity, ultimately causing its function of compensating for cylinder liner thermal deformation to fail, affecting the reliability of the compressor. (From the perspective of performance indicators, nickel-based alloy materials such as Inconel 718 can be selected, but there are high prices, high supplier thresholds, and the failure risk caused by temperature and hydrogen environment cannot be completely eliminated.)

[0019] A spring is placed at the end of the main sealing ring furthest from the cylinder liner. When the cylinder liner undergoes axial expansion or contraction, the pressure on the main sealing ring at the cylinder liner end changes. During this process, the spring is further compressed or rebounded, reducing the change in elastic deformation of the main sealing ring caused by the axial deformation of the cylinder liner (e.g., depending on the specific main sealing ring selection, the spring adaptively deforms to ensure that the main sealing ring always experiences an axial compression rate of 30%~35% in both cold and hot states of the cylinder block). This achieves the purpose of protecting the main sealing ring and ensuring its axial sealing performance against the cavity. For example, when the cylinder liner elongates, the spring is further compressed (the end of the spring supporting the main sealing ring retracts relative to the cylinder liner), reducing the axial compression on the main sealing ring and effectively preventing premature aging of the main sealing ring due to excessive compression. When the cylinder liner shortens, the spring adaptively rebounds (the end of the spring supporting the main sealing ring advances relative to the cylinder liner), reducing the axial rebound of the main sealing ring caused by the shortening of the cylinder liner. This maintains the sealing pressure ratio between the inner and outer sides of the main sealing ring, effectively preventing the main sealing ring from becoming excessively relaxed. This leads to a decrease in the axial sealing performance of the cavity. Regarding the configuration of the main sealing ring and the spring in this structure, in the hydrogen leakage direction of the cavity, the spring is located downstream of the main sealing ring. That is, in the hydrogen leakage direction, the main sealing ring acts as a physical barrier for hydrogen. Compared with the existing technology that directly uses the spring to support the cylinder liner end to achieve elastic support for the cylinder liner, it can effectively avoid the spring being directly exposed to the hydrogen environment. Therefore, the relative position configuration of the spring, main sealing ring and cylinder liner provided by this solution, the main sealing ring is not only used to achieve cylinder leakage sealing, but also, from the perspective of hydrogen embrittlement and hydrogen erosion caused by hydrogen to the spring, it can effectively reduce the impact of hydrogen on the spring performance. In this way, according to the design of different compressor exhaust temperatures, springs with moderate hydrogen resistance can be selected from the perspective of budget cost and supply source, avoiding the problems of increased compressor operating costs and limited selection space caused by the need to use top-grade hydrogen-resistant materials for elastic elements (such as using iron-nickel-based high-temperature alloy springs or stainless steel springs, avoiding reliance on nickel-based alloy materials such as Inconel 718 and Inconel 625).

[0020] The sealing assembly also includes a pressure ring disposed in the cavity, the pressure ring being located on the side of the spring away from the main sealing ring, the pressure ring serving as a support structure between the inner end of the cylinder head and the end of the spring;

[0021] The sealing assembly also includes a load-bearing ring disposed in the cavity, the load-bearing ring serving as a support structure between the spring end and the main sealing ring end.

[0022] The above provides a specific implementation of a sealing component, wherein the outer end of the spring is indirectly supported on the inner end face of the cylinder head through a pressure ring, and the inner end of the spring indirectly provides elastic support to the main sealing ring through a bearing ring. In specific applications, since the outer end of the pressure ring is always supported on the cylinder head, and the bearing ring needs to slide relative to the cylinder head in sync with the change in the spring deformation, the inner side of the pressure ring and the end plate on the cylinder head can adopt any matching method. The matching relationship between the bearing ring and the end plate must meet the requirement that the bearing ring and the end plate have a clearance fit relationship under both cold and hot conditions of the cylinder body, so as to meet the requirement of the bearing ring sliding without resistance relative to the end plate. Furthermore, the outer side of the end plate and the outer side of the bearing ring both have deformation space in the cavity. Using the above methods, regarding the configuration of the pressure ring: On the one hand, the thickness design of the pressure ring and the bearing ring matches the initial support state of the spring on the main sealing ring; on the other hand, as a separate component, the pressure ring, through material selection (using tool steel, high-strength stainless steel, etc.) and end face finishing (grinding), ensures that the inner end of the pressure ring can well adapt to the localized concentrated contact force from the small contact area of ​​the spring (such as a disc spring assembly, where only the inner ring of the outer end of the disc spring assembly contacts the inner end line of the pressure ring). This contact force, through the force diffusion effect of the pressure ring, can effectively avoid crushing pits and fretting wear pits on the inner end of the cylinder head, affecting the force-displacement characteristics of the spring and ultimately reducing the thermal compensation accuracy of the cylinder liner; Regarding the configuration of the bearing ring: On the one hand, regardless of whether the spring uses a disc spring assembly or a corrugated spring, its inner end cannot provide a flat surface for the main sealing ring. On the support surface, the support ring acts as a force-dispersing structure between the spring and the main sealing ring. By providing planar support to the outer end of the main sealing ring, it effectively prevents premature aging of the main sealing ring due to local overpressure or uneven compression, and reduces sealing reliability due to uneven circumferential sealing performance. On the other hand, in the face of vibrations during the operation of the hydrogen compressor, the support ring isolates the disc spring from direct contact with the main sealing ring and increases the contact area to the outer end of the main sealing ring, effectively protecting the main sealing ring and reducing wear damage caused by vibration. Furthermore, as the back ring of the main sealing ring away from the cylinder liner side (high-pressure side), the support ring provides to the back side (outer end) of the main sealing ring effectively prevents the main sealing ring from being squeezed outward to the outer area of ​​the spring under gas pressure and cylinder liner thrust, thereby improving the sealing reliability of the main sealing ring against axial hydrogen leakage.

[0023] The outer corners of the main sealing ring are both rounded.

[0024] In the above scheme, the rounded surfaces set at the corner positions on the inner and outer sides of the outer end face of the main sealing ring are used to form cavities located on the inner and outer sides of the inner end face of the bearing ring. These cavities are used to prevent the main sealing ring from being partially squeezed into the space between the bearing ring and the end plate, and to prevent the main sealing ring from being partially squeezed into the space between the bearing ring and the cylinder liner bore, which would cause premature cracks to appear on the main sealing ring and lead to premature failure of the main sealing ring due to further expansion of the cracks.

[0025] A secondary sealing ring is provided in the gap between the outer wall of the pressure ring and the inner wall of the cylinder, and in the gap between the inner wall of the pressure ring and the side wall of the cylinder head. The secondary sealing ring serves as an axial sealing ring in the corresponding gap.

[0026] It also includes nitrogen purging holes provided on the cylinder barrel, the number of which is greater than or equal to 2, and each of the nitrogen purging holes has one opening located on the cylinder barrel surface and the other opening exposed in the cavity and located between the pressure ring and the bearing ring.

[0027] The above provides a specific implementation of a sealing component. In this solution, on the one hand, secondary sealing rings are configured in the gap between the outer wall of the pressure ring and the inner wall of the cylinder (cylinder liner bore wall), and in the gap between the inner wall of the pressure ring and the side wall of the cylinder head end plate. The secondary sealing rings are used to prevent the gas inside the pressure ring from leaking axially to the outside of the pressure ring. On the other hand, a nitrogen replacement hole is configured on the cylinder liner to replace the gas between the pressure ring and the main sealing ring. This aims to solve the following problems: Hydrogen is the gas with the smallest molecular size and has extremely strong permeability. A main sealing ring with good performance and condition can control the hydrogen leakage rate to an extremely low level (such as less than 10 ml per hour), but it cannot achieve zero hydrogen leakage. When hydrogen leaks to the outer end of the main sealing ring, direct venting will pose a safety hazard to the environment and will also make the hydrogen partial pressure of the environment where the spring is located uncontrollable.

[0028] In this design, the secondary sealing ring serves as the axial sealing ring at the pressure ring position, preventing nitrogen introduced through the nitrogen purging hole and hydrogen from the main sealing ring from leaking further to the outer end of the pressure ring. Gas exiting through the nitrogen purging hole is treated by high-level venting or flare combustion, ensuring that the gas released into the environment is safe. For the spring installation space, continuously supplied nitrogen replaces the air and hydrogen in the surrounding environment, maintaining an oxygen-deficient and low hydrogen partial pressure atmosphere. This fundamentally prevents the formation of an explosive gas mixture in the space and ensures the spring is properly purged. The hydrogen concentration in the space is controlled at a lower level to eliminate the conditions for forming a hydrogen embrittlement and hydrogen erosion gas phase environment that affects the spring characteristics, thereby protecting the spring. While ensuring the spring's lifespan, it also allows the use of commonly used high-quality spring steel and stainless steel with good thermal stability. For abnormal hydrogen leakage after the main sealing ring's sealing performance is reduced, the sealing performance of the main sealing ring can be predicted and evaluated by detecting changes in the hydrogen content of the gas discharged from the nitrogen replacement hole (which serves as the outlet) and / or changes in the pressure of the space where the spring is located. This enables predictive maintenance of the compressor cylinder head seal and facilitates the development of compressor shutdown maintenance plans.

[0029] As those skilled in the art, the technical terms "main sealing ring" and "sub-sealing ring" used in this solution are merely for distinguishing different sealing components on the sealing assembly. Furthermore, considering the need to accommodate the radial deformation of the outer space of the pressure ring, when both the inner and outer sub-sealing rings of the pressure ring are O-rings, the cross-sectional diameter of the outer wall sub-sealing ring is larger than that of the inner wall sub-sealing ring. This ensures that the outer wall sub-sealing ring maintains ideal axial sealing performance even under greater deformation. Regarding the nitrogen pressure introduced into the space where the spring is located through the nitrogen replacement holes, if the gas extracted through the nitrogen replacement holes is treated by torch combustion, a slightly positive pressure (e.g., gauge pressure less than 0.1 MPa) is sufficient. A nitrogen replacement hole quantity greater than or equal to two should be understood as follows: in this cylinder block used in a compressor, and during compressor operation, some nitrogen replacement holes serve as nitrogen inlets to introduce nitrogen into the space where the spring is located, while others serve as mixed gas exhaust holes to discharge the gas in the space where the spring is located to the outside of the cylinder block.

[0030] The nitrogen replacement orifice includes a first replacement orifice and a second replacement orifice, the first replacement orifice having an opening exposed on the bottom side of the cavity, and the second replacement orifice having an opening exposed on the top side of the cavity.

[0031] The above describes a specific method for setting up nitrogen purging holes. The first purging hole serves as a nitrogen inlet, and the second purging hole serves as a mixed gas exhaust hole. This method utilizes the fact that hydrogen has a lower density than nitrogen, allowing hydrogen leaking from the main sealing ring to be fully and efficiently replaced by nitrogen in the upward flow pattern within the spring space. As a specific application, to facilitate the installation of the nitrogen purging holes, they are straight holes extending radially along the cylinder barrel.

[0032] It also includes a gas detection device configured for the second displacement orifice, the gas detection device being connected to the orifice of the second displacement orifice located on the cylinder surface, the gas detection being used to detect the concentration of hydrogen in the gas discharged from the second displacement orifice.

[0033] The above solution, as proposed above, utilizes a gas detection device to detect the hydrogen concentration of the gas discharged from the outlet of the second displacement hole, thereby monitoring the sealing performance of the main sealing ring. While monitoring the sealing performance of the main sealing ring can also be achieved by directly or indirectly monitoring the pressure in the space where the spring is located, compared to directly detecting the hydrogen concentration using a gas detection device, judging the sealing performance of the main sealing ring through pressure monitoring has a larger error margin or places higher demands on the accuracy of the corresponding pressure sensor.

[0034] The main sealing ring and the secondary sealing ring are O-rings or wedges;

[0035] The cylinder head provides radial support to the cylinder liner via an endplate that extends into the cylinder barrel;

[0036] Both the pressure ring and the load-bearing ring are sleeved on the end platform, and the inner side of the load-bearing ring is in clearance fit with the end platform and the outer side is in clearance fit with the cylinder.

[0037] The cross-sectional diameter of the secondary sealing ring between the outer wall of the pressure ring and the inner wall of the cylinder is larger than the cross-sectional diameter of the secondary sealing ring between the inner wall of the pressure ring and the side wall of the cylinder head.

[0038] The spring is either a disc spring assembly or a corrugated spring fitted on the end plate. The disc spring assembly is formed by stacking multiple disc springs. The corrugated spring is an overall ring structure that is deformed in a wave-like shape along its circumferential direction.

[0039] The above provides a specific structural form and configuration of cylinder barrel, cylinder head, and sealing components. The corresponding sealing ring uses an O-ring. Compared to wedge-shaped sealing rings, O-rings are not only lower in cost but also have higher standardization in supply chain parameters and performance, are easier to install, and have no complex internal failure points under stress. In specific implementation, annular grooves are provided on the inner and outer sides of the pressure ring to accommodate the O-ring as a secondary sealing ring. Furthermore, the pressure difference across the secondary sealing ring is small at this location. Under this selection and assembly method, the secondary sealing ring has ideal anti-extrusion performance to maintain its reliability. For the main sealing ring, the load-bearing ring serves as its low-pressure side back plate. Therefore, even if an O-ring is used as the main sealing ring, the main sealing ring also has ideal anti-extrusion performance and reliability. In applications where the compressor discharge pressure is greater than 30 MPa, to reduce the hydrogen leakage rate at the main sealing ring location, a wedge-shaped sealing ring with better sealing performance is preferred for the main sealing ring. In the cylinder head configuration, the end plate provides a stable radial position for the pressure ring, spring, load-bearing ring, main sealing ring, and cylinder liner. The above clearance fit is to ensure the sliding characteristics of the bearing ring along the end plate axial direction; the selection of the cross-sectional diameter is intended to achieve: the secondary sealing ring with a larger cross-sectional diameter on the outer wall of the pressure ring is used to adapt to the sealing performance under the thermal deformation of the pressure ring, and the secondary sealing ring with a smaller cross-sectional diameter on the inner wall of the pressure ring is used to ensure the positioning quality of the end plate radially positioning the pressure ring. In specific applications, the number of secondary sealing rings on the inner wall of the pressure ring can be further increased to be greater than the number of secondary sealing rings on the outer wall of the pressure ring; the above provides a specific implementation of the spring. The disc spring assembly or the corrugated spring can provide uniform elastic support in the circumferential direction to the main sealing ring through the bearing ring. When the disc spring assembly is used, the spring has a constant force deformation range, which is beneficial to maintaining the compression deformation of the main sealing ring under different axial deformation of the cylinder liner. However, it requires stacking multiple disc springs, which requires a higher axial length of the cavity. When the corrugated spring is used, it has a lower requirement for the axial length of the cavity, but there may be difficulties in selecting the existing corrugated spring. Those skilled in the art can reasonably select the type of spring according to their own parts supply situation, etc.

[0040] The structure formed by the cylinder and piston rod seat is an integral cast structure;

[0041] The cylinder head is bolted to the cylinder barrel, and a sealing ring is held between the cylinder barrel end face and the cylinder head end face, the sealing ring serving as a radial sealing ring for the gap between the two.

[0042] The above provides a specific form of cylinder block. On the one hand, the cylinder barrel and piston rod seat are cast as a single unit, which aims to avoid the need for static seals between the cylinder barrel and piston rod seat, thereby optimizing the overall sealing performance of the cylinder block. On the other hand, a sealing ring is provided between the mating ends of the cylinder barrel and cylinder head. This sealing ring serves as a supplement to the leakage of hydrogen from the main sealing ring to the outside of the cylinder block (in the case of not using a secondary sealing ring), or as a supplement to the leakage of gas from the secondary sealing ring to the outside of the cylinder block (in the case of using a secondary sealing ring), which can effectively ensure the safety of the hydrogen pressurized environment.

[0043] This solution also relates to a bidirectional reciprocating hydrogen compressor, including a piston rod and piston rings, and a cylinder structure as described in any of the above, wherein the piston rings are disposed in the cylinder liner, and the piston rod cooperates with a piston rod seat and extends to the outside of the piston rod seat;

[0044] It also includes a stuffing box sealing structure for sealing the cavity between the piston rod seat and the piston rod, the stuffing box sealing structure including a stuffing box assembly filled in the cavity between the piston rod seat and the piston rod, and the stuffing box sealing structure also includes a pressure plate bolted to the piston rod seat for providing pressure to the stuffing box assembly;

[0045] The stuffing box assembly includes multiple partitions disposed in the cavity between the piston rod seat and the piston rod. The partitions are spaced apart along the piston rod axis, and sealing packing is filled between any adjacent partitions. The pressure plate is provided with a central hole through which the piston rod passes, and a hydrogen sensor for detecting the hydrogen content inside the pressure plate is provided in the central hole.

[0046] The above-described bidirectional reciprocating hydrogen compressor, employing the aforementioned cylinder structure, differs from existing technologies in that its stuffing box sealing structure uses a pressure plate and bolts connecting the pressure plate to the piston rod seat. These bolts are used to adjust the compression of the stuffing box assembly, achieving a balance between hydrogen sealing quality and the contact force between the stuffing box assembly and the piston rod. The stuffing box assembly includes multiple baffles and sealing packing filling the gaps between the baffles. This design addresses the following issues: the baffles, as rigid structures at the dynamic sealing positions of the piston rod, have inner channels that provide radial constraint on the piston rod, which is beneficial for controlling the piston rod's fit and movement accuracy. By avoiding uneven wear, it helps maintain the sealing gap at the corresponding dynamic sealing positions on the cylinder assembly and ensures a constant sealing gap at all circumferential positions. Furthermore, the baffles can provide a structural basis for setting up lubrication oil passages (or gas passages, specifically introducing inert gas at the baffle positions to form a pressure barrier within the stuffing box assembly, which prevents hydrogen leakage). For example, for the dynamic sealing surface between the stuffing box assembly and the piston rod, sealing materials are provided on each baffle to facilitate the sealing of this dynamic sealing surface. The oil injection hole allows for multi-point lubrication of the dynamic sealing surface. This multi-point lubrication provides excellent lubrication, ensuring the lifespan of the stuffing box seal structure and improving compressor efficiency. The alternating spacing of the sealing packings, separated by baffles, serves several purposes. First, this structure provides inter-stage throttling for each sealing stage (each packing is considered a primary sealing stage) and minimizes pressure differentials across each stage. This multi-stage throttling and pressure-reducing leakage path for hydrogen gas balances the load on each packing, benefiting the overall lifespan of the stuffing box assembly. Second, the spaced baffles efficiently transfer the frictional heat between the packings and the piston rod to the piston rod seat, preventing the pure packing from accumulating to a greater thickness and causing localized high temperatures and premature packing failure due to poor heat dissipation. Third, the force dispersion effect of the baffles and the planar support provided by their end faces evenly distribute the force across each packing end face, effectively improving the utilization rate of the packings at each location and enhancing the overall sealing performance.

[0047] Preferably, the cavities between any adjacent partitions are completely filled with sealing packing, each sealing packing is an annular integral structure, and each sealing packing has an annular groove coaxial with the sealing packing on its end face. The end face of the partition is provided with an annular protrusion embedded in the annular groove.

[0048] The pressure plate is provided with a central hole through which the piston rod passes, and the central hole is provided with a hydrogen sensor for detecting the hydrogen content inside.

[0049] In the above scheme, the sealing packing completely fills the cavity. On the one hand, this avoids the adverse effects of gas expansion and contraction due to thermal expansion and contraction on the performance of the stuffing box assembly caused by gaps between the baffles. On the other hand, it ensures the reliability of the radial seal for gas leakage channels between the baffles and the sealing packing. The sealing packing is an integral structure with annular grooves, and the baffle end face has annular protrusions. On the one hand, this ensures the structural and positional stability of the sealing packing, and creates axial and radial constraints between the sealing packing and the baffle. By reducing the circumferential relative rotation or radial misalignment between the sealing packing and the baffle during compressor operation, it reduces wear on the sealing packing to maintain its lifespan. On the other hand, it forms a labyrinthine leakage path in the radial direction, thereby ensuring the radial sealing effect. The hydrogen sensor is used to monitor the hydrogen leakage level at the location of the stuffing box seal structure. It aims to assess the current state of the stuffing box seal structure, guide the clamping force of the pressure plate on the stuffing box assembly, and meet the high-standard safety requirements of the hydrogen pressurization process.

[0050] The present invention has the following beneficial effects:

[0051] In the above cylinder block structure, the main sealing ring and piston rod seat provide axial constraints for both ends of the cylinder liner. This avoids the need for bosses on the cylinder liner, thus preventing potential breakage at the boss connection point during later use. Simultaneously, because one end of the cylinder liner is constrained by the main sealing ring, the flexible structure of the main sealing ring allows the cylinder liner to stretch and contract relative to the cylinder barrel on its outer end face during axial thermal deformation. This accommodates the differentiated thermal deformation of the cylinder barrel and cylinder liner, preventing restricted axial elongation of the cylinder liner and radial deformation due to thermal stress, which would severely affect the fit quality between the piston ring and cylinder liner.

[0052] In the above cylinder block structure, by configuring both the main sealing ring and the cylinder liner on the equal-diameter section of the cylinder liner bore, and by configuring rounded surfaces at the corner positions of the inner and outer sides of the inner end face of the main sealing ring, the rounded surfaces at the outer end face of the cylinder liner are used to form cavities located on the inner and outer sides of the outer end of the cylinder liner. When hydrogen leaks through the mating surfaces of the inner and outer sides of the cylinder liner at the main sealing ring position, the above main sealing ring structure design and its configuration with the cylinder liner in the cylinder liner bore can effectively prevent the main sealing ring from being squeezed into the mating surfaces of the inner and outer sides of the cylinder liner, which would cause premature cracking on the main sealing ring and failure due to further crack expansion, thus achieving the purpose of extending the service life of the main sealing ring. Attached Figure Description

[0053] Figure 1 This is a partial cross-sectional view of a hydrogen compressor cylinder structure in the prior art;

[0054] Figure 2 for Figure 1Enlarged view of part A in the middle;

[0055] Figure 3 This is a partial cross-sectional view of a specific embodiment of the cylinder block structure described in this solution;

[0056] Figure 4 for Figure 3 Enlarged view of part B in the middle;

[0057] Figure 5 for Figure 3 A magnified view of part C in the middle.

[0058] The reference numerals in the attached figures are as follows: 1. Gas passage assembly; 2. Cylinder; 3. Sealing ring; 4. Piston rod seat; 5. O-ring seal; 6. Clearance; 7. Gas port assembly; 8. Cylinder liner; 9. Cylinder head; 10. Sealing structure; 11. Sealing assembly; 12. Pressure ring; 13. Spring; 14. Load-bearing ring; 15. Main sealing ring; 16. Secondary sealing ring; 17. Nitrogen replacement hole; 18. Piston rod; 19. Piston ring; 20. Stuffing gland assembly; 21. Pressure plate; 22. Partition plate; 23. Sealing packing; 24. Center hole; 25. Rounded surface; 26. First mating surface; 27. Second mating surface. Detailed Implementation

[0059] The present invention will be further described in detail below with reference to the embodiments, but the present invention is not limited to the following embodiments:

[0060] Example 1:

[0061] like Figures 3 to 5 As shown, the cylinder structure of the bidirectional reciprocating hydrogen compressor includes a cylinder 2, one end of which is provided with a cylinder head 9 and the other end with a piston rod seat 4. A cylinder liner 8 is lined in the cylinder liner bore of the cylinder 2. The inner end of the cylinder head 9 extends into the cylinder liner 8 and provides radial support for the cylinder liner 8. One end of the cylinder liner 8 is supported on the inner end face of the piston rod seat 4, and the other end of the cylinder liner 8 is provided with a sealing assembly 11.

[0062] The sealing assembly 11 includes a main sealing ring 15 disposed in the cavity between the cylinder 2 and the cylinder head 9. The main sealing ring 15 serves as an axial seal in the cavity: the outer side of the main sealing ring 15 is supported and pressed against the cylinder liner bore wall, and the inner side of the main sealing ring 15 is supported and pressed against the end plate of the cylinder head 9.

[0063] The main sealing ring 15 and the cylinder liner 8 are both disposed on the equal diameter section of the cylinder liner bore. The inner end face of the main sealing ring 15 is in contact with the outer end face of the cylinder liner 8. The inner and outer corner positions of the inner end face of the main sealing ring 15 are provided with rounded surfaces 25.

[0064] In this scheme, the cylinder body is also referred to as a cylinder, which is used to provide the compression chamber of the compressor. The compression chamber is specifically located inside the cylinder liner 8. When used in a compressor, a piston ring 19 is fitted inside the cylinder liner 8. The piston rod 18 connected to the piston ring 19 extends to the outside of the piston rod seat 4 through the hole on the piston rod seat 4. The other end of the piston rod 18 is connected to the drive unit. Depending on the specific design of the compressor, the power unit can be a drive motor or a hydraulic drive system, etc.

[0065] Unlike existing technologies, this solution aims to address the following issues: Figure 1 In the provided cylinder block structure, to accommodate the thermal deformation of the cylinder liner 8, which differs from that of the cylinder barrel 2, existing methods include setting a gap 6 between the cylinder liner 8 and the piston rod seat 4. This gap 6 serves as a space to accommodate the cylinder liner 8 when it elongates relative to the cylinder barrel 2. Although the gap 6 solves the problem of thermal deformation of the cylinder liner 8, depending on the deformation of the cylinder liner 8 at different compressor temperatures, when the gap 6 exists, the positional constraint of the cylinder liner 8 in the axial direction of the cylinder barrel 2 is achieved only at the end of the cylinder liner 8 with the boss (the cylinder liner 8 only has a fixed support point at the cylinder head 9 end). In this structural form, during use, the axial force from the piston ring 19 on the cylinder liner 8 can easily cause the cylinder liner 8 to break at the boss connection position. Even after breakage, the cylinder liner 8 may axially move and rotate within the cylinder barrel 2 along with the piston ring 19. When the cylinder liner 8 undergoes excessive deformation and the contact force with the piston rod seat 4 is too large, the axial elongation of the cylinder liner 8 is restricted, which may seriously affect the piston ring 19. The aforementioned problems, particularly the fit quality between the piston ring 19 and cylinder liner 8, pose serious threats to the reliability of the compressor. To address these issues, a cylinder structure is provided where the main sealing ring 15 is located at the end of the cylinder liner 8. Specifically, the inner end of the cylinder liner 8 is supported on the inner end face of the piston rod seat 4, while the other end is supported on the cylinder head 9 via the main sealing ring 15. This structure provides axial constraint to both ends of the cylinder liner 8, stabilizing its position within the cylinder barrel 2. This avoids the possibility of breakage at the connection point of the boss on the cylinder liner 8. Furthermore, since the end structure of the outer end face of the cylinder liner 8 is a flexible main sealing ring 15, when the cylinder liner 8 undergoes axial thermal deformation, it expands and contracts relative to the cylinder barrel 2 on its outer end face to accommodate the differentiated thermal deformation of the cylinder barrel 2 and the cylinder liner 8. This prevents the axial elongation of the cylinder liner 8 from being restricted, which would severely affect the fit quality between the piston ring 19 and the cylinder liner 8.

[0066] Furthermore, for the bidirectional reciprocating hydrogen compressor, the existing design includes: a group of air holes 7 is provided on both end sidewalls of the cylinder liner 8; each end of the group of air holes 7 includes an inlet hole and an outlet hole; the inlet holes at both ends of the cylinder liner 8 are connected to the air passage assembly 1 on the cylinder barrel 2 for connecting the intake air passage; the outlet holes at both ends of the cylinder liner 8 are connected to the air passage assembly 1 on the cylinder barrel 2 for connecting the exhaust air passage. Under this structural design, the mating surface between the outer side of the cylinder liner 8 and the cylinder barrel 2 is defined as the second mating surface 27, and the mating surface between the inner side of the cylinder liner 8 and the cylinder head 9 is defined as the first mating surface 2. 6. When piston ring 19 moves towards piston rod seat 4, the piston rod seat 4 side is the compression side, and the cylinder head 9 side is the intake side. At this time, under the influence of pressure difference, the physical properties of hydrogen, and the fit between cylinder liner 8, cylinder barrel 2, and cylinder head 9, the gradually increasing pressure on the compression side may cause hydrogen to leak towards the main sealing ring 15 through the second mating surface 27. Similarly, when piston ring 19 moves towards cylinder head 9, the piston rod seat 4 side is the intake side, and the cylinder head 9 side is the compression side. At this time, the gradually increasing pressure on the compression side may cause hydrogen to leak towards the main sealing ring 15 through the first mating surface 26. To address leakage in the direction of the sealing ring 15, this solution involves configuring both the main sealing ring 15 and the cylinder liner 8 on equal-diameter sections of the cylinder liner bore. Rounded surfaces 25 are provided at the corner positions on both the inner and outer sides of the inner end face of the main sealing ring 15. Thus, at the outer end face of the cylinder liner 8, the rounded surfaces 25 form cavities outside the first mating surface 26 and the second mating surface 27. When hydrogen leaks through the second mating surface 27, the cavities formed by the rounded surfaces 25 at the corner positions on the inner side of the inner end face of the main sealing ring 15 prevent the main sealing ring 15 from being partially squeezed into the first mating surface. In section 26, when hydrogen leaks through the first mating surface 26, the cavity formed by the rounded surface 25 at the outer corner of the inner end face of the main sealing ring 15 is used to prevent the main sealing ring 15 from being partially squeezed into the second mating surface 27. Therefore, by adopting the above structural design of the main sealing ring 15 and its configuration with the cylinder liner 8 in the cylinder liner bore, it is possible to effectively prevent the main sealing ring 15 from being squeezed into the first mating surface 26 and the second mating surface 27 on the cylinder liner 8 side, which would cause premature cracking on the main sealing ring 15 and failure due to further crack expansion, thereby extending the service life of the main sealing ring 15.

[0067] As those skilled in the art will recognize, the equal-diameter section refers to a section on the cylinder liner bore with the same inner diameter at all axial positions. In specific implementations, the cylinder liner bore can be an equal-diameter bore. The above-mentioned setting of the corresponding corner positions as rounded surfaces 25 aims to make the outer surface of the main sealing ring 15 a smooth surface, thus preventing local stress concentration when the main sealing ring 15 is deformed under pressure. This would prevent premature cracking of the main sealing ring 15 and subsequent crack propagation during use, affecting the sealing performance and lifespan of the main sealing ring 15. When the rounded surface 25 is replaced with a chamfered surface, it also prevents the main sealing ring 15 from being partially squeezed into the first mating surface 26 and the second mating surface 27 towards the cylinder liner 8. Those skilled in the art should consider such a replacement as an equivalent technical solution.

[0068] In a specific application, the cylinder liner 8 is a regular cylindrical structure with the same inner diameter and outer diameter at all positions along the axial direction. To achieve anti-rotation constraint of the cylinder liner 8 relative to the cylinder barrel 2 and to reduce leakage between the cylinder liner 8 and the cylinder barrel 2, the cylinder liner 8 is interference-fitted with the cylinder liner bore (as those skilled in the art know, due to limitations in processing quality and differentiated radial deformation at different positions of the cylinder liner 8 and the cylinder liner bore, such a fit method still cannot eliminate axial hydrogen leakage occurring at the second mating surface 27). The outer hole section on the outer end face of the cylinder liner 8 on the cylinder liner bore and the end platform extending into the stepped hole on the cylinder head 9 form the cavity. This cavity provides installation space for installing the sealing assembly 11. The main sealing ring 15 is an elastic sealing ring, preferably a PTFE composite elastic sealing ring, a PEEK composite material sealing ring, a perfluoroether rubber O-ring sealing ring, etc., which have strong pressure bearing capacity and are resistant to hydrogen permeation. The spring 13 is a disc spring assembly or a corrugated spring, preferably a disc spring assembly that can relatively stably maintain the sealing pressure of the main sealing ring 15. The above-mentioned main sealing ring 15 is suitable for hydrogen compressors with exhaust pressure less than 100 MPa. When the exhaust pressure of the hydrogen compressor exceeds 100 MPa, the main sealing ring 15 should preferably adopt a structure in which an elastic material is wrapped around the outer periphery of a metal elastic skeleton. For example, the metal elastic skeleton can be a ring-shaped helical spring made of nickel-based alloy. The elastic material wrapped around the metal elastic skeleton is used to form a soft wrapping layer to fill the micro gaps on the sealing surface. When the outer end face of the main sealing ring 15 is directly supported on the cylinder head 9, the elastic material can be a soft metal, such as pure silver or pure copper (to protect the elastic material, the surface roughness of the sealing mating surfaces of the inner and outer sides of the main sealing ring 15 should preferably be set to Ra0.1μm~Ra0.15μm). When the outer end face of the main sealing ring 15 is floatingly supported on the cylinder head 9 by the spring 13, the elastic material is preferably PTFE material to form an elastic layer with excellent tear resistance (the surface roughness of the sealing mating surfaces of the inner and outer sides of the main sealing ring 15 should preferably be set to less than Ra0.2μm).

[0069] Example 2:

[0070] This embodiment is a further refinement of embodiment 1:

[0071] The sealing assembly 11 also includes a spring 13 disposed in the cavity. The spring 13 is disposed on the side of the main sealing ring 15 away from the cylinder liner 8, and the spring 13 serves as an elastic support structure that provides axial support to the main sealing ring 15.

[0072] In the above scheme, the spring 13 is used to form an elastic support for the main sealing ring 15, aiming to address the following issues: When the cylinder liner 8 and the cylinder barrel 2 undergo differentiated axial deformation, the spring 13 undergoes elastic deformation of different amounts under the thrust / deformation of the cylinder liner 8. This not only provides deformation space for the axial expansion and contraction of the cylinder liner 8 relative to the cylinder barrel 2, but also stabilizes the heating position of the cylinder liner 8 within the cylinder barrel 2. Simultaneously, the configuration of the main sealing ring 15 and the spring 13 in this structure forms a hydrogen isolation barrier serving the spring 13. For example, in hydrogen refueling station applications, high-pressure compression (e.g., from 25 MPa to 90 MPa) may cause the compressor exhaust temperature to exceed 200°C; in the design of portable compressors, to achieve compressor miniaturization and compact design, a simpler cooling system (including cylinder block cooling module) is needed. The cooling system and interstage cooling modules may cause the compressor exhaust temperature to exceed 200°C. When the cooling system or exhaust valve fails, the compressor exhaust temperature may even exceed 200°C. In the above scenarios, the spring 13, which is directly exposed to hydrogen and acts as an elastic element, will gradually lose its function due to hydrogen embrittlement and hydrogen corrosion under high temperature and high hydrogen partial pressure (especially at the end of the spring 13 and in the crack defect area). This will cause its force-displacement characteristics to drift or even lose elasticity, ultimately causing its thermal deformation compensation function for the cylinder liner 8 to fail, affecting the reliability of the compressor. (From the perspective of performance indicators, nickel-based alloy materials such as Inconel 718 can be selected, but they are expensive, have high supplier thresholds, and still cannot completely eliminate the failure risk caused by temperature and hydrogen environment.)

[0073] A spring 13 is placed at the end of the main sealing ring 15 furthest from the cylinder liner 8. When the cylinder liner 8 undergoes axial expansion and contraction, the pressure on the main sealing ring 15 at the end of the cylinder liner 8 changes. During this process, the spring 13 further compresses or rebounds, reducing the change in elastic deformation of the main sealing ring 15 caused by the axial deformation of the cylinder liner 8 (e.g., depending on the specific main sealing ring 15 selection, the spring 13 adaptively deforms, ensuring that the main sealing ring 15 always experiences an axial compression rate of 30%~35% in both cold and hot states of the cylinder block). This protects the main sealing ring 15 and ensures the main sealing ring 15's alignment with the cavity shaft. For the purpose of improving sealing performance, for example, when the cylinder liner 8 elongates, the spring 13 is further compressed (the end of the spring 13 supporting the main sealing ring 15 retracts relative to the cylinder liner 8), reducing the axial compression on the main sealing ring 15. This effectively prevents the main sealing ring 15 from aging prematurely due to excessive compression. When the cylinder liner 8 shortens, the spring 13 adaptively rebounds (the end of the spring 13 supporting the main sealing ring 15 advances relative to the cylinder liner 8), reducing the axial rebound of the main sealing ring 15 caused by the shortening of the cylinder liner 8. This maintains the sealing pressure ratio between the inner and outer sides of the main sealing ring 15. This effectively prevents the main sealing ring 15 from becoming too loose and causing a decrease in its axial sealing performance over the cavity. Regarding the configuration of the main sealing ring 15 and the spring 13 in this structure, in the hydrogen leakage direction of the cavity, the spring 13 is located downstream of the main sealing ring 15. That is, in the hydrogen leakage direction, the main sealing ring 15 acts as a physical barrier against hydrogen. Compared to the prior art where the spring 13 directly supports the end of the cylinder liner 8 to achieve elastic support for the cylinder liner 8, this effectively prevents the spring 13 from being directly exposed to the hydrogen environment. Therefore, the relative positions of the spring 13, the main sealing ring 15, and the cylinder liner 8 provided in this solution are... In this configuration, the main sealing ring 15 not only seals against cylinder leakage, but also effectively reduces the impact of hydrogen on the performance of the spring 13 from the perspective of hydrogen embrittlement and hydrogen erosion caused by hydrogen. Thus, based on different compressor exhaust temperatures, springs 13 with moderate hydrogen resistance can be selected from the perspectives of budget cost and supply source, avoiding problems such as increased compressor operating costs and limited selection of accessories caused by the need to use top-grade hydrogen-resistant materials for elastic elements (such as using iron-nickel-based high-temperature alloy springs 13 or stainless steel springs, avoiding reliance on nickel-based alloy materials such as Inconel 718 and Inconel 625).

[0074] Example 3:

[0075] This embodiment is a further refinement of embodiment 2:

[0076] The sealing assembly 11 also includes a pressure ring 12 disposed in the cavity. The pressure ring 12 is located on the side of the spring 13 away from the main sealing ring 15. The pressure ring 12 serves as a support structure between the inner end of the cylinder head 9 and the end of the spring 13.

[0077] The sealing assembly 11 also includes a load-bearing ring 14 disposed in the cavity, the load-bearing ring 14 serving as a support structure between the end of the spring 13 and the end of the main sealing ring 15.

[0078] The above provides a specific implementation of the sealing component 11, namely, the outer end of the spring 13 is indirectly supported on the inner end face of the cylinder head 9 through the pressure ring 12, and the inner end of the spring 13 indirectly provides elastic support to the main sealing ring 15 through the bearing ring 14. In specific applications, since the outer end of the pressure ring 12 is always supported on the cylinder head 9, and the bearing ring 14 needs to slide relative to the cylinder head 9 in sync with the deformation of the spring 13, the inner side of the pressure ring 12 and the end plate on the cylinder head 9 can adopt any matching method. The matching relationship between the bearing ring 14 and the end plate needs to meet the requirement that the bearing ring 14 and the end plate have a clearance matching relationship under both cold and hot conditions of the cylinder body, so as to meet the requirement that the bearing ring 14 slides relative to the end plate without resistance. Furthermore, the outer side of the end plate and the outer side of the bearing ring 14 both have deformation space in the cavity. Using the above methods, regarding the configuration of the pressure ring 12: On the one hand, the thickness design of the pressure ring 12 and the bearing ring 14 matches the initial support state of the spring 13 for the main sealing ring 15; on the other hand, as a separate part, the pressure ring 12, through material selection (using tool steel, high-strength stainless steel, etc.) and end face finishing (grinding), allows the inner end of the pressure ring 12 to well adapt to the local concentrated contact force from the small contact area of ​​the spring 13 (such as the spring 13 of a disc spring assembly, where only the outer inner ring of the disc spring assembly contacts the inner end line of the pressure ring 12). This contact force, through the force diffusion effect of the pressure ring 12, can effectively avoid crushing pits and fretting wear pits on the inner end of the cylinder head 9, affecting the force-displacement characteristics of the spring 13, and ultimately reducing the thermal compensation accuracy of the cylinder liner 8; Regarding the configuration of the bearing ring 14: On the one hand, regardless of whether the spring 13 uses a disc spring assembly or a corrugated spring, its inner end cannot provide a flat support for the main sealing ring 15. The supporting ring 14 serves as a force-dispersing structure between the spring 13 and the main sealing ring 15. By providing planar support to the outer end of the main sealing ring 15, it effectively prevents premature aging of the main sealing ring 15 due to local overpressure or uneven compression, and reduces sealing reliability due to uneven circumferential sealing performance. On the other hand, in the face of vibrations during the operation of the hydrogen compressor, the supporting ring 14 isolates the disc spring from direct contact with the main sealing ring 15 and increases the contact area to the outer end of the main sealing ring 15, effectively protecting the main sealing ring 15 and reducing wear damage caused by vibration. Furthermore, as the back ring of the main sealing ring 15 away from the cylinder liner 8 (high-pressure side), the supporting ring 14 provides back (outer end) support to the main sealing ring 15, effectively preventing the main sealing ring 15 from being squeezed outward to the outer area of ​​the spring 13 under gas pressure and the thrust of the cylinder liner 8, thereby improving the sealing reliability of the main sealing ring 15 against axial hydrogen leakage.

[0079] Example 4:

[0080] This embodiment is a further refinement of embodiment 3:

[0081] The outer corners of the main sealing ring 15 are provided with rounded surfaces 25.

[0082] In the above scheme, the rounded surfaces 25 located at the corner positions on the inner and outer sides of the outer end face of the main sealing ring 15 are used to form cavities located on the inner and outer sides of the inner end face of the bearing ring 14. These cavities are used to prevent the main sealing ring 15 from being partially squeezed into the space between the bearing ring 14 and the end plate, and to prevent the main sealing ring 15 from being partially squeezed into the space between the bearing ring 14 and the cylinder liner bore, which would cause premature cracks to appear on the main sealing ring 15 and cause premature failure of the main sealing ring 15 due to further expansion of the cracks.

[0083] Example 5:

[0084] This embodiment is a further refinement of embodiment 3:

[0085] A secondary sealing ring 16 is provided in the gap between the outer wall of the pressure ring 12 and the inner wall of the cylinder 2, and in the gap between the inner wall of the pressure ring 12 and the side wall of the cylinder head 9. The secondary sealing ring 16 serves as an axial sealing ring in the corresponding gap.

[0086] It also includes nitrogen replacement holes 17 provided on the cylinder 2, the number of nitrogen replacement holes 17 is greater than or equal to 2, and each nitrogen replacement hole 17 has one opening located on the surface of the cylinder 2, and the other opening exposed in the cavity and located between the pressure ring 12 and the bearing ring 14.

[0087] The above provides a specific implementation of the sealing component 11. In this solution, on the one hand, a secondary sealing ring 16 is provided in the gap between the outer wall of the pressure ring 12 and the inner wall of the cylinder 2 (cylinder sleeve bore wall), and in the gap between the inner wall of the pressure ring 12 and the side wall of the cylinder head 9 end platform. The secondary sealing ring 16 is used to prevent the gas inside the pressure ring 12 from axially leaking to the outside of the pressure ring 12. On the other hand, a nitrogen replacement hole 17 is provided on the cylinder sleeve 8 for replacing the gas between the pressure ring 12 and the main sealing ring 15. This is intended to solve the following problems: Hydrogen is the gas with the smallest molecular size and has extremely strong permeability. The main sealing ring 15 with good performance and condition can control the hydrogen leakage rate to an extremely low level (such as less than 10 ml per hour), but it cannot achieve zero hydrogen leakage. When hydrogen leaks to the outer end of the main sealing ring 15, direct venting will pose a safety hazard to the environment and will also make the hydrogen partial pressure of the environment where the spring 13 is located uncontrollable.

[0088] In this design, the secondary sealing ring 16 serves as the axial sealing ring at the pressure ring 12 position, preventing nitrogen introduced through the nitrogen replacement hole 17 and hydrogen from the main sealing ring 15 from leaking further to the outer end of the pressure ring 12. The gas exiting through the nitrogen replacement hole 17 is treated by high-level venting or flare combustion, ensuring that the gas released into the environment is safe. For the space containing the spring 13, continuously supplied nitrogen replaces the air and hydrogen in the environment surrounding the spring 13, maintaining an oxygen-deficient and low hydrogen partial pressure atmosphere in this space. This fundamentally prevents the formation of an explosive gas mixture in the space and ensures that the spring 13 is properly sealed by nitrogen replacement. The hydrogen concentration in the space where spring 13 is located is controlled at a lower level, eliminating the conditions for forming a hydrogen embrittlement and hydrogen erosion gas phase environment that affect the characteristics of spring 13, thereby protecting spring 13. On the basis of ensuring the life of spring 13, spring 13 can be made of commonly used high-quality spring steel or stainless steel with good thermal stability. For abnormal hydrogen leakage after the sealing performance of main sealing ring 15 is reduced, the sealing performance of main sealing ring 15 can be predicted and evaluated by detecting the change in hydrogen content of the gas discharged from nitrogen replacement hole 17, which serves as the outlet, and / or the pressure change in the space where spring 13 is located. This enables predictive maintenance of compressor cylinder head 9 seal and facilitates the formulation of compressor shutdown maintenance plans.

[0089] As those skilled in the art, the technical terms "main sealing ring 15" and "sub-sealing ring 16" used in this solution are merely for distinguishing different sealing components on the sealing assembly 11. Furthermore, considering the need to accommodate the outward radial deformation of the outer space of the pressure ring 12, when both the inner and outer sub-sealing rings 16 of the pressure ring 12 are O-rings, the cross-sectional diameter of the outer wall sub-sealing ring 16 of the pressure ring 12 is larger than the cross-sectional diameter of the inner wall sub-sealing ring 16. This ensures that the outer wall sub-sealing ring 16 of the pressure ring 12 maintains ideal axial sealing performance even under greater deformation. Nitrogen pressure is introduced into the space where spring 13 is located through nitrogen replacement port 17. If the gas drawn out through nitrogen replacement port 17 is treated by torch combustion, the nitrogen pressure can be slightly positive (e.g., gauge pressure less than 0.1 MPa). If there are two or more nitrogen replacement ports 17, it should be understood that in this cylinder block used in the compressor and during the operation of the compressor, some nitrogen replacement ports 17 are used as nitrogen inlet ports to introduce nitrogen into the space where spring 13 is located, and some nitrogen replacement ports 17 are used as mixed gas exhaust ports to exhaust the gas in the space where spring 13 is located to the outside of the cylinder block.

[0090] Example 6:

[0091] This embodiment is a further refinement of embodiment 5:

[0092] The nitrogen replacement hole 17 includes a first replacement hole and a second replacement hole. The first replacement hole has an opening exposed on the bottom side of the cavity, and the second replacement hole has an opening exposed on the top side of the cavity.

[0093] The above describes a specific arrangement of the nitrogen replacement hole 17, where the first replacement hole serves as a nitrogen inlet and the second replacement hole serves as a mixed gas exhaust hole. This arrangement utilizes the characteristic that hydrogen density is lower than nitrogen density, allowing hydrogen leaking from the main sealing ring 15 to be fully and efficiently replaced by nitrogen in the upward flow pattern within the space occupied by the spring 13. As a specific application, to facilitate the installation of the nitrogen replacement hole 17, it is a straight hole extending radially along the cylinder 2.

[0094] Example 7:

[0095] This embodiment is a further refinement of embodiment 6:

[0096] It also includes a gas detection device configured for the second displacement hole, the gas detection device being connected to the orifice of the second displacement hole located on the surface of the cylinder 2, the gas detection being used to detect the concentration of hydrogen in the gas discharged from the second displacement hole.

[0097] The above solution, as proposed above, utilizes a gas detection device to detect the hydrogen concentration of the gas discharged from the outlet of the second displacement hole, thereby monitoring the sealing performance of the main sealing ring 15. While monitoring the sealing performance of the main sealing ring 15 can also be achieved by directly or indirectly monitoring the pressure in the space where the spring 13 is located, compared to directly detecting the hydrogen concentration using a gas detection device, judging the sealing performance of the main sealing ring 15 through pressure monitoring has a larger error margin or places higher demands on the accuracy of the corresponding pressure sensor.

[0098] Example 8:

[0099] This embodiment is a further refinement of embodiment 5:

[0100] The main sealing ring 15 and the secondary sealing ring 16 are O-rings or wedges;

[0101] Cylinder head 9 provides radial support to cylinder liner 8 via an end plate extending into cylinder barrel 2;

[0102] Both the pressure ring 12 and the load-bearing ring 14 are sleeved on the end platform. The inner side of the load-bearing ring 14 is in clearance fit with the end platform and the outer side is in clearance fit with the cylinder 2.

[0103] The cross-sectional diameter of the secondary sealing ring 16 between the outer wall of the pressure ring 12 and the inner wall of the cylinder 2 is larger than the cross-sectional diameter of the secondary sealing ring 16 between the inner wall of the pressure ring 12 and the side wall of the cylinder head 9.

[0104] The spring 13 is either a disc spring assembly or a corrugated spring fitted on the end plate. The disc spring assembly is formed by stacking multiple disc springs. The corrugated spring is an overall ring structure that is deformed in a wave-like shape along its circumferential direction.

[0105] The above provides a specific structural form and configuration of the cylinder barrel 2, cylinder head 9, and sealing assembly 11. The corresponding sealing ring uses an O-ring. Compared to using a wedge-shaped sealing ring, the O-ring is not only lower in cost, but also has higher standardization in supply chain parameters and performance, is simpler to install, and has no complex internal failure points under stress. In specific implementation, the inner and outer sides of the pressure ring 12 are respectively provided with annular grooves to accommodate the O-ring serving as the secondary sealing ring 16, and the pressure difference between the two sides of the secondary sealing ring 16 at this location is small. Under this selection and assembly method, the secondary sealing ring 16 has ideal anti-extrusion performance. To maintain its performance reliability, and considering that the main sealing ring 15 and the load-bearing ring 14 serve as its low-pressure side back plate, even if an O-ring is used as the main sealing ring 15, the main sealing ring 15 still has ideal anti-extrusion performance and performance reliability. In applications where the compressor discharge pressure is greater than 30 MPa, to reduce the hydrogen leakage rate at the location of the main sealing ring 15, a wedge-shaped sealing ring with better sealing performance is preferred for the main sealing ring 15. In the configuration of the cylinder head 9, the end plate provides a stable radial position for the pressure ring 12, spring 13, load-bearing ring 14, main sealing ring 15, and cylinder liner 8. Constraints; the above clearance fit ensures the sliding characteristics of the bearing ring 14 along the end platen axial direction; the selection of the cross-sectional diameter aims to achieve: the secondary sealing ring 16 with a larger cross-sectional diameter on the outer wall of the pressure ring 12 is used to adapt to the sealing performance under the thermal deformation of the pressure ring 12, and the secondary sealing ring 16 with a smaller cross-sectional diameter on the inner wall of the pressure ring 12 is used to ensure the positioning quality of the end platen in the radial positioning of the pressure ring 12. In specific applications, the number of secondary sealing rings 16 on the inner wall of the pressure ring 12 can be further adopted to be greater than the number of secondary sealing rings 16 on the outer wall of the pressure ring 12; the above provides a specific implementation of the spring 13, disc spring assembly or Both corrugated springs can provide uniform elastic support in the circumferential direction to the main sealing ring 15 through the bearing ring 14. When a disc spring assembly is used, the spring 13 has a constant force deformation range, which is beneficial for controlling the compression deformation of the main sealing ring 15 under different axial deformation of the cylinder liner 8. However, multiple disc springs need to be stacked, which requires a higher axial length of the cavity. When a corrugated spring is used, the requirement for the axial length of the cavity is lower, but there may be difficulties in selecting existing corrugated springs. Those skilled in the art can reasonably select the type of spring 13 based on their own parts supply and other factors.

[0106] Example 9:

[0107] This embodiment is a further refinement of embodiment 1:

[0108] The structure formed by the cylinder 2 and the piston rod seat 4 is an integral cast structure;

[0109] The cylinder head 9 is bolted to the cylinder barrel 2, and a sealing ring 3 is held between the end face of the cylinder barrel 2 and the end face of the cylinder head 9. The sealing ring 3 serves as a radial sealing ring for the gap between the two.

[0110] The above provides a specific form of cylinder block. On the one hand, the cylinder barrel 2 and the piston rod seat 4 are cast as a whole, which aims to avoid the need to set a static seal between the cylinder barrel 2 and the piston rod seat 4, thereby optimizing the overall sealing performance of the cylinder block. On the other hand, a sealing ring 3 is set between the mating ends of the cylinder barrel 2 and the cylinder head 9. This sealing ring 3 serves as a supplement to the leakage of hydrogen gas from the main sealing ring 15 to the outside of the cylinder block (in the case of not using the secondary sealing ring 16), or as a supplement to the leakage of gas from the secondary sealing ring 16 to the outside of the cylinder block (in the case of using the secondary sealing ring 16), which can effectively ensure the safety of the hydrogen pressurization environment 12.

[0111] Example 10:

[0112] Based on Embodiment 1, this embodiment provides a bidirectional reciprocating hydrogen compressor, including a piston rod 18 and a piston ring 19, and also includes the cylinder structure described in Embodiment 1. The piston ring 19 is disposed in the cylinder liner 8, and the piston rod 18 cooperates with the piston rod seat 4 and extends to the outside of the piston rod seat 4.

[0113] It also includes a stuffing box sealing structure for sealing the cavity between the piston rod seat 4 and the piston rod 18. The stuffing box sealing structure includes a stuffing box assembly 20 filled in the cavity between the piston rod seat 4 and the piston rod 18. The stuffing box sealing structure also includes a pressure plate 21 bolted to the piston rod seat 4 and used to provide pressure to the stuffing box assembly 20.

[0114] The stuffing box assembly 20 includes multiple partition plates 22 disposed in the cavity between the piston rod seat 4 and the piston rod 18. The partition plates 22 are arranged at intervals along the axial direction of the piston rod 18, and sealing filler 23 is filled between any adjacent partition plates 22. The pressure plate 21 is provided with a central hole 24 through which the piston rod 18 passes. The central hole 24 is provided with a hydrogen sensor for detecting the hydrogen content inside.

[0115] The above-described bidirectional reciprocating hydrogen compressor uses the aforementioned cylinder structure. Unlike existing technologies, the stuffing box seal structure employs a pressure plate 21 and bolts connecting the pressure plate 21 to the piston rod seat 4. These bolts are used to adjust the compression of the stuffing box assembly 20, achieving a balance between hydrogen sealing quality and the contact force between the stuffing box assembly 20 and the piston rod 18. The stuffing box assembly 20 includes multiple partitions 22 and sealing packing 23 filling the gaps between the partitions 22. This design addresses the following issue: the partitions 22 serve as rigid structures at the dynamic sealing position of the piston rod 18, and their inner channels can be used for... The piston rod 18 provides radial constraint, which is beneficial for controlling the fitting accuracy and motion accuracy of the piston rod 18. By avoiding uneven wear, it helps maintain the sealing gap at the corresponding dynamic sealing position on the cylinder assembly and keeps the sealing gap constant at all circumferential positions. Furthermore, the partition 22 can provide a structural basis for setting up a lubrication oil passage (or a gas passage, specifically introducing inert gas at the partition 22 position to form a pressure barrier in the stuffing box assembly 20, which is used to prevent hydrogen leakage). For example, for the dynamic sealing surface between the stuffing box assembly 20 and the piston rod 18, by setting a gas path on each partition 22 to the dynamic sealing surface between the piston rod 18 and ... The oil injection hole for injecting lubricating oil into the dynamic sealing surface enables multi-point lubrication of the dynamic sealing surface. This multi-point lubrication provides excellent lubrication, ensuring the lifespan of the stuffing box seal structure and improving compressor efficiency. The sealing packings 23, as part of the specific dynamic sealing structure, are alternately arranged with partitions 22 between them. This structure serves as a throttling mechanism between sealing stages (each sealing packing 23 is considered a first-level sealing stage) and a sealing structure with a small pressure difference across each sealing stage. This multi-stage throttling and pressure-reducing leakage channel formed by hydrogen can balance the load on each sealing packing 23, thus extending the overall lifespan of the stuffing box assembly 20. On the one hand, the frictional heat between the sealing packing 23 and the piston rod 18 can be efficiently transferred to the piston rod seat 4 through multiple spaced partitions 22, avoiding the problem of local high temperature due to poor heat dissipation caused by the pure sealing packing 23 accumulating to a larger thickness, which leads to premature failure of the sealing packing 23. On the other hand, through the force dispersion effect of the partitions 22 and the planar support provided by the end face of the partitions 22 to the sealing packing 23, the force evenly applied to the end face of each sealing packing 23 can effectively improve the utilization rate of the sealing packing 23 at each position, which is beneficial to the overall sealing effect.

[0116] Example 11:

[0117] This embodiment is a further refinement of embodiment 10:

[0118] The cavities between any adjacent partitions 22 are completely filled by sealing fillers 23. Each sealing filler 23 is an annular integral structure. Each sealing filler 23 has an annular groove coaxial with the sealing filler 23 on its end face. The end face of the partition 22 is provided with an annular protrusion embedded in the annular groove.

[0119] The pressure plate 21 is provided with a central hole 24 through which the piston rod 18 passes. The central hole 24 is provided with a hydrogen sensor for detecting the hydrogen content inside.

[0120] In the above scheme, the sealing packing 23 completely fills the cavity. On the one hand, it avoids the adverse effects of gas expansion and contraction due to thermal expansion and contraction on the performance of the stuffing box assembly 20 caused by the cavities between the partitions 22. On the other hand, it ensures the reliability of the radial seal of the gas leakage channel between the partitions 22 and the sealing packing 23. The sealing packing 23 is an integral structure with an annular groove, and the end face of the partition 22 has an annular protrusion. On the one hand, it ensures the structural and positional stability of the sealing packing 23 and forms axial and radial constraints between the sealing packing 23 and the partitions 22. By reducing the circumferential relative rotation or radial misalignment of the sealing packing 23 and the partitions 22 during compressor operation, it reduces the wear on the sealing packing 23 to maintain its lifespan. On the other hand, it forms a labyrinthine leakage path in the radial direction, thereby ensuring the radial sealing effect. The hydrogen sensor is used to monitor the hydrogen leakage level at the location of the stuffing box sealing structure. It aims to assess the current state of the stuffing box sealing structure, guide the operation of the pressure plate 21 to tighten the stuffing box assembly 20, and meet the high-standard safety requirements of the hydrogen pressurization process.

[0121] The above description, in conjunction with specific preferred embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific embodiments of the present invention are limited to these descriptions. For those skilled in the art, other embodiments derived without departing from the technical solution of the present invention should be included within the scope of protection of the present invention.

Claims

1. A cylinder block structure for a bidirectional reciprocating hydrogen compressor, comprising a cylinder barrel (2), wherein a cylinder head (9) is disposed at one end of the cylinder barrel (2), and a piston rod seat (4) is disposed at the other end; a cylinder liner (8) is lined in the cylinder liner bore of the cylinder barrel (2); the inner end of the cylinder head (9) extends into the cylinder liner (8) and provides radial support for the cylinder liner (8), characterized in that, One end of the cylinder liner (8) is supported on the inner end face of the piston rod seat (4), and the other end of the cylinder liner (8) is provided with a sealing assembly (11). The sealing assembly (11) includes a main sealing ring (15) disposed in the cavity between the cylinder (2) and the cylinder head (9), the main sealing ring (15) serving as an axial seal in the cavity: the outer side of the main sealing ring (15) is supported and pressed against the cylinder bore wall, and the inner side of the main sealing ring (15) is supported and pressed against the end plate of the cylinder head (9). The main sealing ring (15) and the cylinder liner (8) are both arranged on the equal diameter section of the cylinder liner hole. The inner end face of the main sealing ring (15) is in contact with the outer end face of the cylinder liner (8). The inner and outer corners of the inner end face of the main sealing ring (15) are provided with rounded surfaces (25). The mating surface between the outer side of the cylinder liner and the cylinder barrel is defined as the second mating surface, and the mating surface between the inner side of the cylinder liner and the cylinder head is defined as the first mating surface. The rounded surface is used to form a cavity located outside the first mating surface and the second mating surface. The sealing assembly (11) also includes a spring (13) disposed in the cavity, the spring (13) being disposed on the side of the main sealing ring (15) away from the cylinder liner (8), the spring (13) serving as an elastic support structure that provides axial support to the main sealing ring (15); The sealing assembly (11) also includes a pressure ring (12) disposed in the cavity, the pressure ring (12) being located on the side of the spring (13) away from the main sealing ring (15), the pressure ring (12) serving as a support structure between the inner end of the cylinder head (9) and the end of the spring (13); The sealing assembly (11) also includes a support ring (14) disposed in the cavity, the support ring (14) serving as a support structure between the end of the spring (13) and the end of the main sealing ring (15); A secondary sealing ring (16) is provided in the gap between the outer wall of the pressure ring (12) and the inner wall of the cylinder (2), and in the gap between the inner wall of the pressure ring (12) and the side wall of the cylinder head (9). The secondary sealing ring (16) serves as an axial sealing ring in the corresponding gap. It also includes nitrogen replacement holes (17) provided on the cylinder (2), the number of nitrogen replacement holes (17) is greater than or equal to 2, and each nitrogen replacement hole (17) has one opening located on the surface of the cylinder (2) and the other opening exposed in the cavity and located between the pressure ring (12) and the bearing ring (14).

2. The cylinder block structure of the bidirectional reciprocating hydrogen compressor according to claim 1, characterized in that, The outer corners of the main sealing ring (15) are provided with rounded surfaces (25).

3. The cylinder block structure of the bidirectional reciprocating hydrogen compressor according to claim 1, characterized in that, The nitrogen replacement hole (17) includes a first replacement hole and a second replacement hole, the first replacement hole having an opening exposed on the bottom side of the cavity and the second replacement hole having an opening exposed on the top side of the cavity.

4. The cylinder structure of the bidirectional reciprocating hydrogen compressor according to claim 3, characterized in that, It also includes a gas detection device configured for the second displacement hole, the gas detection device being connected to the orifice of the second displacement hole located on the surface of the cylinder (2), the gas detection being used to detect the concentration of hydrogen in the gas discharged from the second displacement hole.

5. The cylinder structure of the bidirectional reciprocating hydrogen compressor according to claim 1, characterized in that, The main sealing ring (15) and the secondary sealing ring (16) are O-rings or wedges; The cylinder head (9) provides radial support to the cylinder liner (8) through an end plate that extends into the cylinder barrel (2); The pressure ring (12) and the load-bearing ring (14) are both sleeved on the end platform. The inner side of the load-bearing ring (14) is in clearance fit with the end platform and the outer side is in clearance fit with the cylinder. The cross-sectional diameter of the secondary sealing ring (16) between the outer wall of the pressure ring (12) and the inner wall of the cylinder (2) is greater than the cross-sectional diameter of the secondary sealing ring (16) between the inner wall of the pressure ring (12) and the side wall of the cylinder head (9); The spring (13) is a disc spring assembly sleeved on the end plate or a corrugated spring sleeved on the end plate. The disc spring assembly is formed by stacking multiple disc spring assemblies. The corrugated spring is an overall ring structure with a wave-like deformation along its circumferential direction.

6. The cylinder block structure of the bidirectional reciprocating hydrogen compressor according to any one of claims 1 to 5, characterized in that, The structure formed by the cylinder (2) and the piston rod seat (4) is an integral casting structure; The cylinder head (9) is bolted to the cylinder barrel (2), and a sealing ring (3) is held between the end face of the cylinder barrel (2) and the end face of the cylinder head (9), and the sealing ring (3) serves as a radial sealing ring for the gap between the two.

7. A bidirectional reciprocating hydrogen compressor, comprising a piston rod (18) and piston rings (19), characterized in that, It also includes the cylinder block structure according to any one of claims 1 to 6, wherein the piston ring (19) is disposed in the cylinder liner (8), and the piston rod (18) cooperates with the piston rod seat (4) and extends to the outside of the piston rod seat (4); It also includes a stuffing box sealing structure for sealing the cavity between the piston rod seat (4) and the piston rod (18), the stuffing box sealing structure including a stuffing box assembly (20) filled in the cavity between the piston rod seat (4) and the piston rod (18), the stuffing box sealing structure also including a pressure plate (21) bolted to the piston rod seat (4) and used to provide pressure to the stuffing box assembly (20). The stuffing box assembly (20) includes multiple partition plates (22) disposed in the cavity between the piston rod seat (4) and the piston rod (18). The partition plates (22) are arranged at intervals along the axial direction of the piston rod (18), and sealing filler (23) is filled between any adjacent partition plates (22). The pressure plate (21) is provided with a central hole (24) through which the piston rod (18) passes. The central hole (24) is provided with a hydrogen sensor for detecting the hydrogen content inside.

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