A kind of positive displacement hydrogen compressor cylinder structure and hydrogen compressor system

Abstract

The application discloses a kind of volumetric hydrogen compressor cylinder structure and hydrogen compressor system, belong to compressor technical field, compressor system includes cylinder structure, cylinder structure includes cylinder, piston assembly, piston rod, piston assembly includes first piston assembly, second piston assembly, first piston assembly and second piston assembly include piston ring and guide ring;Piston rod is provided with gas guide hole, annular groove is formed between first piston assembly and second piston assembly, one end of gas guide hole is communicated with annular groove;Still include pressure-reducing cylinder, cavity is configured in pressure-reducing cylinder, when piston assembly is in gas compression stroke, the other end of gas guide hole is communicated with cavity;Still include pressure sensor for measuring pressure in cavity.The structure design provided in the scheme can realize the on-line monitoring of piston assembly and cylinder wall sealing condition, compared with vibration monitoring, sound wave monitoring and other technologies, can avoid the adverse effects brought by data extraction and analysis process to monitoring result.

Description

Technical Field

[0001] This invention relates to the field of compressor technology, specifically to a cylinder structure for a positive displacement hydrogen compressor and a hydrogen compressor system. Background Technology

[0002] A hydrogen compressor is a type of compressor that compresses hydrogen gas. Compared to air compressors, hydrogen is more prone to leakage through tiny gaps, heats up rapidly during compression, and can cause hydrogen embrittlement of materials. Therefore, the performance characteristics of hydrogen compressors include not only resistance to hydrogen embrittlement (generally achieved through material selection and heat treatment), but also superior leak-proof performance and compressor temperature control. Furthermore, depending on the intended use of the compressed hydrogen gas, piston-based hydrogen compressors employ both oil-lubricated and oil-free lubrication methods. Oil-free lubrication is used in applications requiring stringent purity of the compressed gas, such as fuel cells. For the leakage prevention performance at the contact point between the piston and cylinder wall in an oilless hydrogen compressor, existing technologies employ a piston consisting of a sealing ring (piston ring) and a support ring made of self-lubricating materials, such as PTFE or PEEK. While these materials possess ideal self-lubricating properties, during the operation of the hydrogen compressor, due to the heat generated by the friction pair and the rapid temperature rise during hydrogen compression, the temperature's impact on the sealing performance at this contact point is primarily as follows: When the sealing ring temperature rises, its thermal expansion exceeds the cylinder's expansion, leading to an increase in the contact force between the piston ring and the cylinder wall. This further increases the temperature at the friction pair location. Under the influence of temperature, the significant decrease in the sealing ring's strength and hardness results in a decrease in the sealing pressure of the friction pair, increasing axial leakage at the piston location in the cylinder. The softened sealing ring itself exhibits reduced wear resistance, causing an increased wear rate and significantly affecting the piston ring's lifespan. The increased temperature also disrupts the transfer film formed by the piston ring's self-lubricating material on the cylinder wall, further increasing the wear rate.

[0003] To achieve axial leakage monitoring of gas at the piston position, patent application CN202511159761.6, entitled "Intelligent Monitoring Method and System for Sealing Performance of Liquid-Driven Compressors," provides a technical solution for monitoring sealing performance based on data processing methods such as frictional sound signals. It also mentions a technical solution for evaluating compressor sealing performance based on vibration signal analysis. Regarding axial leakage monitoring, conventional methods also include those based on exhaust volume and pressure analysis, fixed-point temperature monitoring, acoustic wave monitoring, and shutdown inspection.

[0004] During the operation of an oil-free hydrogen compressor, axial leakage between the piston and cylinder wall is relatively easy to occur. The most direct impact of this axial leakage is a decrease in exhaust volume, a decrease in exhaust pressure, a decrease in operating efficiency, and an increase in operating costs. Therefore, further optimizing the cylinder structure of the hydrogen compressor to facilitate the monitoring of the aforementioned axial leakage is of great significance for the further development of hydrogen energy technology and the promotion of hydrogen energy utilization. Summary of the Invention

[0005] To address the aforementioned issues regarding the optimization of the hydrogen compressor cylinder structure, the present invention aims to provide a positive displacement hydrogen compressor cylinder structure and a hydrogen compressor system. The structural design provided by this solution not only enables online monitoring of the sealing condition between the piston assembly and the cylinder wall, but also avoids the adverse effects of data extraction and analysis processes on the monitoring results compared to technologies based on vibration monitoring and acoustic monitoring.

[0006] The objective of this invention is mainly achieved through the following technical solution: a cylinder structure for a volumetric hydrogen compressor, comprising a cylinder, a piston assembly installed in the cylinder, and a piston rod connected to the piston assembly. The piston assembly includes a first piston assembly and a second piston assembly, which are installed on the piston rod at intervals. Both the first piston assembly and the second piston assembly include piston rings and guide rings.

[0007] The piston rod is provided with an air guide hole, and an annular groove is formed between the first piston assembly and the second piston assembly. One end of the air guide hole communicates with the annular groove.

[0008] It also includes a pressure-collecting cylinder, which has a closed cavity. The piston rod passes through the pressure-collecting cylinder and through the cavity. The other end of the air guide hole is configured such that when the piston assembly is in the gas compression stroke, the other end of the air guide hole communicates with the cavity.

[0009] It also includes a pressure sensor installed on the pressure sampling cylinder for measuring the pressure in the cavity.

[0010] In this solution, the cylinder body is the cylinder barrel of the compressor cylinder body structure, which is used to provide the piston chamber. The piston assembly is installed in the piston chamber of the cylinder body. When the compressor is working, the piston assembly moves with the piston rod to compress the gas in the piston chamber.

[0011] This solution addresses the challenges of sealing hydrogen during the operation of a positive displacement hydrogen compressor, particularly the difficulty in sealing hydrogen itself and the significant impact of temperature on piston ring sealing performance during compression. It provides a solution that addresses the online monitoring of the piston assembly and cylinder wall seal by designing the piston assembly, air guide holes, and pressure measurement. By directly measuring pressure, this solution avoids the adverse effects of data extraction and analysis on the monitoring results compared to existing monitoring methods based on vibration or acoustic monitoring.

[0012] Specifically, in this design, the piston assembly includes a first piston assembly and a second piston assembly, designed to cooperate with the cylinder wall to form an annular groove between the first and second piston assemblies. The first and second piston assemblies serve as axial sealing structures at different ends of the annular groove. Both the first and second piston assemblies form axial sealing surfaces with the cylinder wall of the cylinder body. When both the first and second piston assemblies can perform their normal axial sealing function, the annular groove and the piston chambers on both sides of the piston assembly are isolated from each other. For example, when the piston assembly is in the gas compression stroke, the pressure in the annular groove will not increase due to an increase in pressure in one side of the piston chamber. That is, in this state, because of the working function of the cylinder body structure... Temperature changes will cause a certain change in the internal pressure in the ring groove, but the range of pressure change and the rate of change are relatively constant under this condition. When the sealing ring on the first or second piston assembly deteriorates due to unavoidable wear, the gas in the compression chamber of the piston cavity will be introduced into the ring groove through the leakage gap between the piston ring and the cylinder wall when the piston assembly is in the gas compression stroke. The gas introduced into the ring groove becomes an interfering factor that disturbs the internal pressure in the ring groove. This interfering factor will disrupt the original pressure change rate and the maximum pressure of the ring groove. By collecting the pressure data in the ring groove in real time, the sealing condition between the piston assembly and the cylinder wall can be determined.

[0013] Furthermore, this solution connects the annular groove to the upper cavity of the pressure-producing cylinder via a vent hole on the piston rod. This vent hole serves as the connection between the annular groove and the upper cavity, allowing the internal pressure of the cavity to change synchronously with the pressure in the annular groove. By installing a pressure sensor on the pressure-producing cylinder, the internal pressure of the annular groove can be monitored. This not only avoids the adverse effects on the detection results caused by signal pickup and processing interference, which are common in traditional online monitoring of piston assembly sealing based on vibration and sound waves, but also eliminates the problem of the pressure sensor being installed directly in the annular groove. Since the cylinder is a non-moving part of the compressor and is minimally or negligibly affected by the heat generated during compression, this solution avoids the problems associated with directly installing the pressure sensor in the annular groove, such as the power supply issues required in a closed environment, the problem of transmitting detection results externally, the serious impact on sensor lifespan due to the pressure sensor's synchronization with the piston assembly movement, and the impact of the internal temperature environment on the accuracy of the pressure detection element.

[0014] As those skilled in the art know, since the pressure-collecting cylinder is located outside the cylinder body, the main path for the heat of compression to be transferred to the pressure-collecting cylinder is the piston rod. The piston rod acts as a heat-conducting bridge, causing the heat of compression to affect the temperature of the gas in the annular groove and the air guide hole. Therefore, in the gas chamber, which includes the cavity, annular groove, and air guide hole, the pressure change and the rate of pressure change in the gas chamber during the compressor's working cycle are all related to the heating capacity of the piston rod on the pressure-collecting cylinder, the heat dissipation capacity of the gas chamber, the volume of the cavity, the volume of the annular groove, and the volume of the air guide hole. Therefore, when the compressor reaches thermal equilibrium and the piston assembly has good sealing performance, the final pressure measured by the pressure sensor, or the pressure rise rate obtained from multiple monitoring results of the pressure sensor, is related to the specific design of the compressor and environmental factors. When using pressure detection results to determine the sealing performance of the piston assembly based on the pressure threshold and the pressure rise rate threshold, the specific design of the compressor and the operating environment should be considered. The specific threshold value is determined by the environment, but for a single compressor, when its operating environment is stable and the compressor is in thermal equilibrium, if there is no leakage between the piston assembly and the cylinder wall, the maximum pressure that the pressure sensor can measure is stable, and the pressure threshold can be used as a standard to judge the sealing performance of the piston assembly. If the pressure measured during the operation of the compressor exceeds the pressure threshold, it is judged that the sealing performance of the piston assembly has decreased, and internal leakage has occurred between the piston assembly and the cylinder wall. At the same time, after internal leakage occurs, or in order to match the design of gas compression, piston assembly life design, etc., there will be internal leakage at the exhaust pressure throughout the entire life cycle of the piston assembly. As long as the internal leakage rate is within the allowable range, that is, after obtaining the pressure rise rate through continuous pressure measurement, if the pressure rise rate is less than the pressure rise rate threshold, it is considered that the piston assembly can still meet the sealing performance requirements at this time, and the sealing performance of the piston assembly in this stage meets the requirements.

[0015] In practical applications, for hydrogen compression, depending on the application, the feed gas can be atmospheric pressure gas or pressurized gas, and the target pressure distribution range of the product gas is relatively wide, commonly ranging from 20 MPa to 70 MPa. Furthermore, the hydrogen compression process often employs multi-stage pressurization. For this solution, for example, when applied to cylinder exhaust pressures greater than 5 MPa, if the initial pressure in the pressure sampling cylinder cavity is atmospheric pressure, the large pressure difference between the annular groove and the compression chamber places higher demands on the sealing performance of the first and second piston assemblies. To address this issue, a preferred method is to configure a pressure-replenishing hole on the pressure sampling cylinder to compensate for the pressure in its inner cavity. This pressure-replenishing hole is based on a pressure-replenishing pipeline... The pressure is replenished to reduce the pressure difference between the two sides of the first and second piston assemblies (the pressure difference between the annular groove and the compression chamber), thereby simplifying the design of the first and second piston assemblies. Furthermore, when applied to scenarios with internal leakage, the pressure in the pressure chamber of the pressure sampling cylinder continuously increases. When a certain value is reached, the sealing ability of the piston assembly and the back pressure established in the annular groove will prevent internal leakage. During subsequent operation of the compressor, as the piston assembly is continuously worn and the sealing ability decreases, the pressure in the annular groove will continue to increase. Therefore, the detection result of the pressure sensor can still serve as an important indicator of the sealing performance of the piston assembly.

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

[0017] The pressure-collecting cylinder is a cylindrical structure with its axis parallel to the piston rod axis, end plates at both ends, and a partition in the center. The cavity includes a first pressure-collecting chamber and a second pressure-collecting chamber separated by the partition.

[0018] The piston rod passes through the partition and the end plates at both ends of the pressure cylinder. The partition is equipped with a first sealing assembly that achieves axial sealing of the gap between its upper channel and the piston rod. The end plates are each equipped with a second sealing assembly that achieves axial sealing of the gap between their respective upper channels and the piston rod.

[0019] Both the first and second pressure sampling chambers are equipped with pressure sensors for measuring the pressure in their respective chambers.

[0020] Both ends of the cylinder are equipped with air inlets and exhaust outlets;

[0021] The first pressure-collecting chamber and the second pressure-collecting chamber are configured such that, during the reciprocating motion of the piston assembly in the cylinder, when the piston assembly compresses the gas on one side of the cylinder, the air guide hole is connected to one of the first pressure-collecting chamber and the second pressure-collecting chamber; when the piston assembly compresses the gas on the other side of the cylinder, the air guide hole is connected to the other of the two.

[0022] The above provides a specific implementation of the pressure-collecting cylinder and its cylinder configuration. Both ends of the cylinder are equipped with air inlets and exhaust ports, forming a double-acting cylinder. The piston chambers on both sides of the piston assembly serve as compression chambers. This implementation, where the piston rod compresses the gas through the piston assembly during both forward and backward movements, results in a highly efficient cylinder with stable exhaust pulsation. In this cylinder configuration, the pressure-collecting cylinder includes a first pressure-collecting chamber and a second pressure-collecting chamber, each equipped with a separate pressure sensor. This aims to achieve the following: for example, when the piston assembly moves forward, compressing the gas in its front compression chamber through the first piston assembly, the annular groove communicates with the second pressure-collecting chamber through a guide hole; when the piston assembly moves backward, compressing the gas in its front compression chamber through the second piston assembly, the annular groove... The second pressure chamber is connected to the first pressure chamber via a vent hole. When the sealing performance of the first piston assembly decreases, the pressure inside the annular groove increases during the forward movement of the piston assembly, which in turn increases the pressure inside the second pressure chamber and can be detected by the corresponding pressure sensor. When the piston assembly moves backward, although the pressurized gas in the annular groove will also pressurize the first pressure chamber, if the sealing performance of the second piston assembly is good, the maximum pressure that the first pressure chamber can reach after pressurization will be less than the pressure in the second pressure chamber and will lag behind the pressure rise in the second pressure chamber. Therefore, this scheme, compared to setting only one pressure chamber in the pressure chamber to determine the overall sealing performance of the piston assembly, can determine the specific sealing performance of the first and second piston assemblies based on the pressure monitoring results of the first and second pressure chambers, which is convenient for intuitive and precise acquisition of the sealing performance of the piston assembly.

[0023] In the above scheme, the first sealing assembly is used to prevent direct internal leakage of the first and second pressure-producing chambers, and the second sealing assembly is used to prevent external gas leakage from the end of the pressure-producing cylinder. Since the pressure difference between the two sides of the sealing assembly at the partition and end plate positions is significantly different, and leakage at the end plate position has an impact on the environment, the second sealing assembly is required to have higher sealing performance. Preferably, the first and second sealing assemblies adopt different sealing structures. The vent hole on the piston rod, specifically the orifice communicating with the pressure-producing cylinder, can be configured such that: when the piston assembly is located at the center of the cylinder's movement trajectory, the orifice is located at the partition position. Thus, it can be configured such that: when the piston rod moves forward, the orifice communicates with the second pressure-producing chamber; when the piston rod moves backward, the orifice communicates with the first pressure-producing chamber.

[0024] The first sealing component is a sealing ring installed in the annular groove of the channel on the partition plate. The number of sealing rings is greater than or equal to 3, and each sealing ring is equipped with an independent annular groove. The second sealing component is a packing sealing component installed on the end plate. The packing sealing component includes packing and a pressure ring for pressing the packing. The packing is disposed in the packing box of the end plate, and the pressure ring is connected to the end plate by a clamping bolt. The end of the pressure ring acts on the packing.

[0025] The above provides a specific implementation of the first sealing component and the second sealing component. As mentioned above, the first sealing component aims to solve the internal leakage problem and the pressure difference between the two sides of the sealing surface is small. Therefore, a reliable seal can be achieved by using a multi-ring sealing structure that is simple in structure and easy to assemble. The sealing ring is an O-ring. The second sealing component aims to solve the external leakage problem and the pressure difference between the two sides of the sealing surface may be relatively large. Therefore, it adopts a structure including packing and a pressure ring to provide reliable sealing at this position. The packing sealing component can adjust the sealing performance at any time by adjusting the pressure ring through the tightening bolt.

[0026] Both the first piston assembly and the second piston assembly are configured to include multiple piston rings, which are stacked in the axial direction of the piston rod, and guide rings are fixed on the piston rod. Guide rings are provided at both ends of the stacked structure, and the stacked structure is sandwiched between the guide rings.

[0027] The piston ring is a plate-shaped structure comprising an outer ring and an inner ring. The outer ring is a polymer material ring, and the inner ring is a metal plate with a central hole. The inner ring is fitted onto the piston rod through the central hole, and the outer ring is fixed to the outer edge of the inner ring. The outer ring is in contact with the cylinder wall of the cylinder block.

[0028] The above solution provides a specific implementation of a piston assembly. Specifically, the piston ring (also known as a sealing ring) is used to prevent leakage in the cylinder at the piston assembly location, preventing gas leakage that is not allowed at the piston assembly location. The guide ring (also known as a support ring) is used on the piston assembly to support the piston assembly in a centered state with the piston cavity, ensuring that the piston assembly reciprocates along the centerline of the piston cavity, preventing direct contact and uneven wear between the piston ring and the cylinder wall, and providing a lateral force support structure to ensure the operational stability of the piston assembly. In this solution, the corresponding piston assembly is configured to have multiple piston rings, aiming to achieve: forming a multi-stage seal in the axial leakage direction, thereby avoiding or reducing leakage while ensuring the life of each piston ring through a step-by-step pressure reduction method; the guide rings at both ends of the stacked structure are intended to provide lateral support to the stacked structure at both ends, thereby reducing or preventing uneven wear or even radial wobble of the piston rings. This design further specifies that the piston ring includes an outer ring and an inner ring. The outer ring is made of a polymer material and serves as the outer ring body of the piston ring. Specifically, it can be made of polyetheretherketone (PEEK), a mature material with good wear resistance and a low coefficient of friction. The inner ring is made of a metal material and serves as the inner ring body of the piston ring. Specifically, it can be made of austenitic stainless steel, which has good thermal conductivity, a low coefficient of thermal expansion, excellent strength and stiffness, and good resistance to hydrogen embrittlement. With this piston ring structure, on the one hand, the inner ring supports the outer ring and enhances the heat dissipation capacity of the inner side of the outer ring to reduce the operating temperature of the outer ring and minimize the impact of frictional heat on the sealing performance and lifespan of the outer ring. On the other hand, from the perspective of the piston ring as a whole, the inner ring, being made of metal, has a smaller thermal expansion than the polymer material, thus effectively reducing the contact force between the outer ring and the cylinder wall under compressor hot conditions. That is, by maintaining a reasonable and relatively constant contact force between the outer ring and the cylinder wall, the lifespan of the piston ring is extended.

[0029] The stacked structure is configured such that, along the axial direction of the piston rod, adjacent outer ring end faces are in contact with each other, adjacent inner ring end faces are in contact with each other, and the inner end faces of the guide rings at both ends of the stacked structure are in contact with the outer ring and the inner ring.

[0030] The above provides a more specific piston assembly structure. In this solution, the outer rings are fitted together, the inner rings are fitted together, and the guide rings at the ends of the stacked structure are fitted together with the outer and inner rings. This makes the first piston assembly and the second piston assembly both multi-layer structures with stable layer-to-layer structures and relative positions. Such a multi-layer structure can effectively ensure the performance reliability of the piston assembly from the perspective of overall vibration and interlayer slip angle.

[0031] The inner ring includes a sleeve and multiple plate rings in the shape of plates. The central hole is a channel on the sleeve. The plate rings are arranged at intervals in the axial direction of the sleeve. The plate rings are all sleeved on the sleeve and welded to the sleeve by a circumferential weld.

[0032] The inner wall of the outer ring is provided with annular grooves in the same number as the number of plate rings. The annular grooves are arranged at intervals on the axis of the outer ring. The outer edge of the plate ring is embedded in the annular grooves, and each annular groove is matched with a plate ring.

[0033] The above provides a specific implementation of the inner ring. The sleeve serves as the connecting skeleton inside the plate ring and provides a central hole for fitting the inner ring onto the piston rod. The plate ring acts as a support ring between the outer ring and the sleeve. The ring weld is preferably formed by laser welding to ensure axial sealing at the weld position and reduce the impact of welding heat on material reliability through welding quality. In this solution, compared to the sleeve length, the plate ring is a thin-walled ring on the inner ring. This thin-walled ring provides support for the inner side of the outer ring. When the cylinder block temperature rises, the plate ring temperature rises synchronously. The thinner plate ring is more prone to conical deformation under the compression of the outer ring expansion and its own expansion. Compared to a single plate ring with the same thickness as the sleeve, the inner ring has less rigid constraint on the outer ring, thereby achieving the purpose of controlling the contact force between the outer ring and the cylinder wall. In this scheme, the plate ring is connected to the outer ring by embedding the outer edge of the plate ring into the annular groove on the inner wall of the outer ring. The aim is to achieve the following: not only does the outer ring achieve positional constraint in the axial direction of the inner ring through a simple structure, but also, for hydrogen, even a small leakage gap can easily lead to hydrogen leakage. By embedding the outer edge of the plate ring into the annular groove, the length of the gas leakage gap between the inner and outer rings can be effectively increased, reducing the possibility of axial leakage of gas through the gap between the inner and outer rings.

[0034] The gaps between the plate rings and the gaps between the plate rings and the guide ring are filled with flexible filler layers.

[0035] In the above scheme, on the one hand, the flexible packing layer is used to fill the gaps at the corresponding positions, so that the side of the plate ring has support from the flexible packing. In this way, during the reciprocating motion and speed change of the piston assembly, the flexible packing layer can effectively constrain the vibration occurring on the plate ring, thereby achieving the purpose of optimizing the stability of the piston ring. On the other hand, the flexible packing layer is used to fill part of the space in the gap to reduce the air gap, thereby reducing the impact of the gas in the air gap on the structural stability and sealing reliability of the piston assembly due to expansion and contraction. Preferably, due to the working temperature of the cylinder structure, the flexible packing layer itself will also undergo a certain degree of thermal expansion. To avoid the impact of thermal expansion on the overall shape of the piston assembly and the contact force with the cylinder wall, it is set that: the flexible packing layer fills part of the space in the gap and / or the flexible packing layer is made of a material with internal voids. With this scheme, the gap not filled by the flexible packing layer forms an air gap and serves as the expansion space for the flexible packing layer. The voids allow the flexible packing layer itself to be compressed. Preferably, the flexible filler layer is made of flexible graphite material or expanded PTFE material with good resilience and long-term reliability in the operating temperature range of the cylinder structure. The flexible filler layer is not suitable for rubber materials that are prone to failure under high temperature and hydrogen influence.

[0036] The cylinder body has a double-layer structure with a bushing on the inner side and an outer cylinder on the outer side. A cold water tank for introducing cooling water into the cylinder body is formed between the outer wall of the bushing and the inner wall of the outer cylinder.

[0037] The above solution provides a specific cylinder block form. In this specific solution, the bushing is made of a hydrogen embrittlement resistant material and provides a smooth cylinder wall. The cold water tank is specifically used to control the cylinder block structure temperature by introducing circulating cooling water into it. The double-layer structure of the cylinder block facilitates the molding of a cold water tank with a spiral structure.

[0038] This solution also relates to a positive displacement hydrogen compressor system, including a drive motor, a middle body, and a cylinder structure. The drive motor is connected to the piston rod of the cylinder structure through the middle body. The middle body is used to convert the rotational motion of the drive motor into the linear reciprocating motion of the piston rod. The cylinder structure is any of the cylinder structures described above.

[0039] The above compressor system is a specific application of the cylinder structure, that is, the compressor system includes the cylinder structure. As those skilled in the art understand it, the drive motor serves as the power source of this system. The power output by the drive motor is transmitted to the piston rod through the central body and drives the piston rod to perform linear reciprocating motion, thus completing the compression of the gas within the cylinder structure.

[0040] A further technical solution for the cylinder block structure of the volumetric hydrogen compressor is as follows:

[0041] It also includes a connecting plate, which includes a connecting plate and multiple reinforcing bars connected to the connecting plate. The reinforcing bars are spaced apart in the circumferential direction of the connecting plate. The pressure-collecting cylinder is a cylindrical structure with a bottom plate at one end and an open end at the other end. The open end of the pressure-collecting cylinder is bolted to the connecting plate through a flange on its outer side. The reinforcing bars are bolted to the shell of the middle body.

[0042] It also includes a processing module, wherein the signal output terminal of the pressure sensor is connected to the signal input terminal of the processing module. The processing module is configured to: collect the pressure measurement results of the pressure sensor and compare them with a preset pressure threshold and a preset pressure rise rate threshold; when it is determined that the pressure measurement result is greater than or equal to the pressure threshold, or the pressure rise rate is greater than or equal to the pressure rise rate threshold, output the piston assembly wear abnormality judgment result.

[0043] The above solution provides a specific connection method for the pressure-collecting cylinder. Specifically, for the pressure-collecting cylinder implementation mentioned above, which isolates the first and second pressure-collecting chambers through a partition, the open end of the pressure-collecting cylinder is used for the configuration and maintenance of the first sealing component. Regarding the end plate, the bottom plate serves as the end plate at one end of the pressure-collecting cylinder, and the second sealing component of this end plate is configured on the outside of the bottom plate. The connecting plate serves as the end plate at the other end of the pressure-collecting cylinder, and the second sealing component of this end plate is configured on the outside of the connecting plate. The connecting disc serves as the intermediate connection structure between the pressure-collecting cylinder and the middle body. The connecting disc is configured to include multiple ribs spaced apart in the circumferential direction of the connecting plate, aiming to utilize the space between the ribs to adjust and maintain the second sealing component on the outside of the connecting plate. The processing module is used to collect the pressure measurement results from the pressure sensor and, based on the pressure threshold and the pressure rise rate threshold, determine whether abnormal wear has occurred in the piston assembly.

[0044] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0045] This solution provides a technical approach to online monitoring of the sealing condition between the piston assembly and the cylinder wall through piston assembly design, air guide hole design, and pressure measurement design. By directly measuring the pressure, this solution avoids the adverse effects of data extraction and analysis processes on the monitoring results compared to existing monitoring solutions based on vibration monitoring, acoustic monitoring, and other technologies. Attached Figure Description

[0046] The accompanying drawings, which are included to provide a further understanding of embodiments of the invention and form part of this application, do not constitute a limitation thereof. In the drawings:

[0047] Figure 1 This is a partial structural schematic diagram of a specific embodiment of the positive displacement hydrogen compressor system described in this invention. The schematic diagram is a partial cross-sectional view.

[0048] Figure 2 for Figure 1 A magnified view of part A in the middle;

[0049] Figure 3 for Figure 1 A magnified view of part A in the middle, compared to Figure 2 , Figure 3 The structure is provided with a flexible filler layer;

[0050] Figure 4 for Figure 3 A magnified view of part B shown;

[0051] Figure 5 for Figure 1 A magnified view of part C shown;

[0052] Figure 6 This is a schematic diagram of the inner ring structure in a specific embodiment of the positive displacement hydrogen compressor cylinder structure described in this solution;

[0053] The labels in the diagram represent:

[0054] 1. Cylinder block; 2. Piston assembly; 21. First piston assembly; 22. Second piston assembly; 3. Piston rod; 4. Pressure production cylinder; 5. Middle body; 6. Exhaust port; 7. Inlet port; 8. Pressure sensor; 9. First pressure production chamber; 10. Second pressure production chamber; 11. Air guide hole; 12. Annular groove; 13. Bushing; 14. Cold water tank; 15. Piston ring; 16. Metal plate; 17. Guide ring; 18. Flexible packing layer; 19. Partition plate; 20. Plate ring; 23. Connecting disc; 24. Sleeve. Detailed Implementation

[0055] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments and accompanying drawings. The illustrative embodiments and descriptions of the present invention are only used to explain the present invention and are not intended to limit the present invention.

[0056] Example 1:

[0057] like Figures 1 to 6 As shown, this embodiment of the invention provides a cylinder structure for a volumetric hydrogen compressor, including a cylinder 1, a piston assembly 2 installed in the cylinder 1, and a piston rod 3 connected to the piston assembly 2. The piston assembly 2 includes a first piston assembly 21 and a second piston assembly 22, which are installed on the piston rod 3 at intervals. Both the first piston assembly 21 and the second piston assembly 22 include piston rings 15 and guide rings 17.

[0058] The piston rod 3 is provided with a gas guide hole 11, and an annular groove 12 is formed between the first piston assembly 21 and the second piston assembly 22. One end of the gas guide hole 11 communicates with the annular groove 12.

[0059] It also includes a pressure-collecting cylinder 4, which has a closed cavity. The piston rod 3 passes through the pressure-collecting cylinder 4 and through the cavity. The other end of the air guide hole 11 is configured such that when the piston assembly 2 is in the gas compression stroke, the other end of the air guide hole 11 communicates with the cavity.

[0060] It also includes a pressure sensor 8 installed on the pressure sampling cylinder 4 for measuring the pressure in the cavity.

[0061] In this scheme, the cylinder 1 is the cylinder barrel of the compressor cylinder 1 structure, which is used to provide the piston chamber. The piston assembly 2 is installed in the piston chamber of the cylinder 1. When the compressor is working, the piston assembly 2 moves with the piston rod 3 to compress the gas in the piston chamber.

[0062] This solution addresses the challenges of sealing hydrogen during the operation of a positive displacement hydrogen compressor, particularly the difficulty in sealing hydrogen itself and the significant impact of temperature on the sealing performance of the piston ring 15 during compression. It provides a solution that utilizes the design of the piston assembly 2, the air guide hole 11, and pressure measurement to enable online monitoring of the seal between the piston assembly 2 and the cylinder wall. By directly measuring pressure, this solution avoids the adverse effects of data extraction and analysis on the monitoring results compared to existing monitoring solutions based on vibration monitoring and acoustic wave monitoring.

[0063] Specifically, in this design, the piston assembly 2 includes a first piston assembly 21 and a second piston assembly 22, designed to cooperate with the cylinder wall to form an annular groove 12 between the first piston assembly 21 and the second piston assembly 22. The first piston assembly 21 and the second piston assembly 22 serve as axial sealing structures at different ends of the annular groove 12. Both the first piston assembly 21 and the second piston assembly 22 form axial sealing surfaces with the cylinder wall of the cylinder body 1. When both the first piston assembly 21 and the second piston assembly 22 can perform normal axial sealing functions, the annular groove 12 is isolated from the piston chambers on both sides of the piston assembly 2. For example, when the piston assembly 2 is in the gas compression stroke, the pressure in the annular groove 12 will not increase due to the increased pressure in one side of the piston chamber of the piston assembly 2. That is, in this state, because the cylinder body... The operating temperature change of the structure will cause a certain change in the internal pressure in the annular groove 12. However, the range of change of the internal pressure in the annular groove 12 under this state is relatively constant, and the rate of change is also relatively constant. When the sealing ring on the first piston assembly 21 or the second piston assembly 22 suffers a decrease in sealing performance due to unavoidable wear, when the piston assembly 2 is in the gas compression stroke, the gas in the compression chamber of the piston chamber will be introduced into the annular groove 12 through the leakage gap between the piston ring 15 and the cylinder wall. The gas introduced into the annular groove 12 becomes an interfering factor that interferes with the internal pressure in the annular groove 12. This interfering factor will disrupt the original pressure change rate and the maximum pressure value of the annular groove 12. By collecting the pressure data in the annular groove 12 in real time, the sealing condition between the piston assembly 2 and the cylinder wall can be determined.

[0064] Furthermore, this solution connects the annular groove 12 to the upper cavity of the pressure-collecting cylinder 4 via a vent hole 11 on the piston rod 3. This allows the vent hole 11 to serve as a connection between the annular groove 12 and the upper cavity of the pressure-collecting cylinder 4, enabling synchronous changes in the internal pressure of the cavity and the annular groove 12. By installing the pressure sensor 8 on the pressure-collecting cylinder 4, the internal pressure of the annular groove 12 can be monitored. This not only avoids the adverse effects on the detection results caused by signal pickup and processing interference, which are common in traditional online monitoring of the piston assembly 2's sealing performance based on vibration and sound waves, but also avoids the problems associated with directly installing the pressure sensor 8 in the annular groove 12. Since the cylinder is a non-moving part of the compressor and is minimally or not affected by the heat generated during compression, this solution avoids the problems associated with directly installing the pressure sensor 8 in the annular groove 12, such as the power supply issues in a closed environment, the problem of transmitting detection results externally, the serious impact on sensor lifespan caused by the synchronous movement of the pressure sensor 8 with the piston assembly 2, and the impact of the temperature environment inside the cylinder 1 on the accuracy of the pressure detection element.

[0065] As those skilled in the art know, since the pressure-collecting cylinder 4 is located outside the cylinder body 1, the main path for the heat of compression to be transferred to the pressure-collecting cylinder 4 is the piston rod 3. The piston rod 3 acts as a heat-conducting bridge, causing the heat of compression to affect the temperature of the gas in the annular groove 12 and the air guide hole 11. Therefore, in the gas chamber including the cavity, the annular groove 12, and the air guide hole 11, the pressure change and the rate of pressure change in the gas chamber during the compressor's working cycle are related to the heating capacity of the piston rod 3 on the pressure-collecting cylinder 4, the heat dissipation capacity of the gas chamber, the volume of the cavity, the volume of the annular groove 12, and the volume of the air guide hole 11. Therefore, when the compressor reaches thermal equilibrium and the piston assembly 2 has good sealing performance, the final pressure measured by the pressure sensor 8, or the pressure rise rate obtained from multiple monitoring results of the pressure sensor 8, is related to the specific design of the compressor and environmental factors. When using the pressure detection results to determine the sealing performance of the piston assembly 2 based on the pressure threshold and the pressure rise rate threshold, it should be based on the specific design of the compressor. The specific threshold value is determined by the design and operating environment. However, for a single compressor, when its operating environment factors are stable and the compressor is in thermal equilibrium, if there is no leakage between the piston assembly 2 and the cylinder wall, the maximum pressure that the pressure sensor 8 can measure is stable. The pressure threshold can be used as a standard to judge the sealing performance of the piston assembly 2. If the pressure measured during the operation of the compressor exceeds the pressure threshold, it is judged that the sealing performance of the piston assembly 2 has decreased and internal leakage has occurred between the piston assembly 2 and the cylinder wall. At the same time, after internal leakage occurs, or in order to match the design of gas compression, piston assembly 2 life design, etc., there will be internal leakage at the exhaust pressure throughout the entire life cycle of the piston assembly 2. As long as the internal leakage rate is within the allowable range, that is, after obtaining the pressure rise rate through continuous pressure measurement, if the pressure rise rate is less than the pressure rise rate threshold, it is considered that the piston assembly 2 can still meet the sealing performance requirements at this time, and the sealing performance of the piston assembly 2 in this stage meets the requirements.

[0066] In practical applications, for hydrogen compression, depending on the application, the feed gas can be atmospheric pressure gas or pressurized gas, and the target pressure distribution range of the product gas is relatively wide, commonly ranging from 20 MPa to 70 MPa. Furthermore, the hydrogen compression process often employs multi-stage pressurization. For this example, when the exhaust pressure of cylinder 1 is greater than 5 MPa, if the initial pressure in the pressure sampling cylinder 4 is atmospheric pressure, the large pressure difference between the annular groove 12 and the compression chamber places higher demands on the sealing performance of the first piston assembly 21 and the second piston assembly 22. To address this issue, preferably, a pressure-replenishing hole is configured on the pressure sampling cylinder 4 to replenish the pressure in its inner cavity. This pressure-replenishing hole replenishes the cavity based on a pressure-replenishing pipeline. This reduces the pressure difference between the two sides of the first piston assembly 21 and the second piston assembly 22 (the pressure difference between the annular groove 12 and the compression chamber), thereby simplifying the design of the first piston assembly 21 and the second piston assembly 22. Furthermore, when applied to scenarios with internal leakage, the pressure in the pressure chamber of the pressure sampling cylinder 4 continuously increases. When a certain value is reached, the sealing ability of the piston assembly 2 and the back pressure established in the annular groove 12 will prevent internal leakage. During the subsequent operation of the compressor, as the piston assembly 2 is continuously worn and its sealing ability decreases, the pressure in the annular groove 12 will continue to increase. Therefore, the detection result of the pressure sensor 8 can still serve as an important indicator of the sealing performance of the piston assembly 2.

[0067] Example 2:

[0068] This embodiment is a further refinement of embodiment 1:

[0069] The pressure-collecting cylinder 4 is a cylindrical structure with its axis parallel to the axis of the piston rod 3, end plates at both ends, and a partition 19 in the center. The cavity includes a first pressure-collecting chamber 9 and a second pressure-collecting chamber 10 separated by the partition 19.

[0070] The piston rod 3 passes through the partition plate 19 and the end plates at both ends of the pressure cylinder 4. The partition plate 19 is equipped with a first sealing assembly that achieves axial sealing of the gap between its upper channel and the piston rod 3. The end plates are each equipped with a second sealing assembly that achieves axial sealing of the gap between their respective upper channels and the piston rod 3.

[0071] Both the first pressure sampling chamber 9 and the second pressure sampling chamber 10 are equipped with pressure sensors 8 for measuring the pressure in their respective chambers;

[0072] Both ends of the cylinder 1 are provided with an air inlet 7 and an exhaust outlet 6;

[0073] The first pressure-collecting chamber 9 and the second pressure-collecting chamber 10 are configured such that, during the reciprocating motion of the piston assembly 2 in the cylinder 1, when the piston assembly 2 compresses the gas on one side of the cylinder 1, the air guide hole 11 communicates with one of the first pressure-collecting chamber 9 and the second pressure-collecting chamber 10, and when the piston assembly 2 compresses the gas on the other side of the cylinder 1, the air guide hole 11 communicates with the other one of the two.

[0074] The above provides a specific implementation of the pressure-collecting cylinder 4 and the cylinder body 1 configuration. Both ends of the cylinder body 1 are equipped with an air inlet 7 and an exhaust port 6, thus forming a double-acting cylinder body 1. The piston chambers on both sides of the piston assembly 2 serve as compression chambers. This implementation, where the piston rod 3 compresses the gas through the piston assembly 2 during both forward and backward movements, results in a highly efficient cylinder body 1 with stable exhaust pulsation. In this cylinder body 1 configuration, the pressure-collecting cylinder 4 includes a first pressure-collecting chamber 9 and a second pressure-collecting chamber 10, each equipped with a separate pressure sensor 8. This aims to achieve the following: For example, when the piston assembly 2 moves forward and compresses the gas in its front compression chamber through the first piston assembly 21, the annular groove 12 communicates with the second pressure-collecting chamber 10 through the air guide hole 11. When the piston assembly 2 moves backward and compresses the gas in its front compression chamber through the second piston assembly 22, the annular groove 12 communicates with the second pressure-collecting chamber 10. 2. The first pressure chamber 21 is connected to the first pressure chamber 9 through the air guide hole 11. When the sealing performance of the first piston assembly 21 decreases, the pressure inside the annular groove 12 increases during the forward movement of the piston assembly 2, which leads to an increase in the internal pressure in the second pressure chamber 10 and can be detected by the corresponding pressure sensor 8. When the piston assembly 2 moves backward, although the pressurized gas in the annular groove 12 will also pressurize the first pressure chamber 9, if the sealing performance of the second piston assembly 22 is good, the maximum pressure that the first pressure chamber 9 can reach after pressurization will be less than the pressure of the second pressure chamber 10 and will lag behind the pressure rise of the second pressure chamber 10. Therefore, this scheme is adopted. Compared with setting only one pressure chamber in the pressure cylinder 4 to determine the overall sealing performance of the piston assembly 2, the specific sealing performance of the first piston assembly 21 and the second piston assembly 22 can be determined based on the pressure monitoring results of the first pressure chamber 9 and the second pressure chamber 10, which makes it easier to obtain the sealing performance of the piston assembly 2 intuitively and in detail.

[0075] In the above scheme, the first sealing assembly is used to prevent direct internal leakage of the first pressure-producing chamber 9 and the second pressure-producing chamber 10, and the second sealing assembly is used to prevent external gas leakage from the end of the pressure-producing cylinder 4. Since there is a significant difference in pressure difference between the two sides of the sealing assembly at the partition plate 19 position and the end plate position, and leakage at the end plate position has an impact on the environment, the second sealing assembly is required to have higher sealing performance. Preferably, the first sealing assembly and the second sealing assembly adopt different sealing structures. The air guide hole 11 on the piston rod 3, which is specifically used to communicate with the pressure-producing cylinder 4, can be configured such that when the piston assembly 2 is located at the center of the movement trajectory of the cylinder 1, the hole is located at the partition plate 19 position. Thus, it can be configured such that when the piston rod 3 moves forward, the hole communicates with the second pressure-producing chamber 10, and when the piston rod 3 moves backward, the hole communicates with the first pressure-producing chamber 9.

[0076] Example 3:

[0077] This embodiment is a further refinement of embodiment 2:

[0078] The first sealing component is a sealing ring installed in the annular groove of the channel on the partition plate 19. The number of sealing rings is greater than or equal to 3, and each sealing ring is equipped with an independent annular groove. The second sealing component is a packing sealing component installed on the end plate. The packing sealing component includes packing and a pressure ring for pressing the packing. The packing is disposed in the packing box of the end plate, and the pressure ring is connected to the end plate by a clamping bolt. The end of the pressure ring acts on the packing.

[0079] The above provides a specific implementation of the first sealing component and the second sealing component. As mentioned above, the first sealing component aims to solve the internal leakage problem and the pressure difference between the two sides of the sealing surface is small. Therefore, a reliable seal can be achieved by using a multi-ring sealing structure that is simple in structure and easy to assemble. The sealing ring is an O-ring. The second sealing component aims to solve the external leakage problem and the pressure difference between the two sides of the sealing surface may be relatively large. Therefore, it adopts a structure including packing and a pressure ring to provide reliable sealing at this position. The packing sealing component can adjust the sealing performance at any time by adjusting the pressure ring through the tightening bolt.

[0080] Example 4:

[0081] This embodiment is a further refinement of embodiment 1:

[0082] Both the first piston assembly 21 and the second piston assembly 22 are configured to include multiple piston rings 15, which are stacked in the axial direction of the piston rod 3, and guide rings 17 are fixed on the piston rod 3. Guide rings 17 are provided at both ends of the stacked structure, and the stacked structure is sandwiched between the guide rings 17.

[0083] The piston ring 15 is a plate-shaped structure including an outer ring and an inner ring. The outer ring is a polymer material ring, and the inner ring is a metal plate 16 with a central hole. The inner ring is sleeved on the piston rod 3 through the central hole. The outer ring is fixed on the outer edge of the inner ring and is in contact with the cylinder wall of the cylinder body 1.

[0084] The above scheme provides a specific implementation of piston assembly 2. Specifically, piston ring 15 (also known as sealing ring) is used to prevent leakage in cylinder 1 at the piston assembly 2 position, and to prevent gas leakage that is not allowed at the piston assembly 2 position. Guide ring 17 (also known as support ring) is used on piston assembly 2 to support piston assembly 2 in a centered state with piston cavity, ensuring that piston assembly 2 reciprocates on the center line of piston cavity, preventing direct contact and uneven wear between piston ring 15 and cylinder wall, and providing lateral force support structure to ensure the operational stability of piston assembly 2. In this scheme, the corresponding piston assembly 2 is configured to have multiple piston rings 15, aiming to achieve: forming multi-stage sealing in the axial leakage direction, and avoiding or reducing leakage by gradually reducing pressure, while ensuring the life of each piston ring 15; guide rings 17 at both ends of the stacked structure are intended to provide lateral support for the stacked structure at both ends, so as to reduce or avoid uneven wear or even radial wobble of piston ring 15. This design further specifies that the piston ring 15 includes an outer ring and an inner ring. The outer ring is made of a polymer material and serves as the outer ring body of the piston ring 15. Specifically, the material can be polyetheretherketone (PEEK), a mature material with good wear resistance and a low coefficient of friction. The inner ring is made of a metal material and serves as the inner ring body of the piston ring 15. Specifically, the material can be austenitic stainless steel, which has good thermal conductivity, a low coefficient of thermal expansion, excellent strength and rigidity, and good resistance to hydrogen embrittlement. With the above-described piston ring 15 structure, on the one hand, the inner ring supports the outer ring and enhances the heat dissipation capacity of the inner side of the outer ring to reduce the operating temperature of the outer ring and reduce the impact of frictional heat on the sealing performance and lifespan of the outer ring. On the other hand, from the perspective of the piston ring 15 as a whole, the inner ring, being made of a metal material, has a smaller thermal expansion than the polymer material, thus effectively reducing the contact force between the outer ring and the cylinder wall under compressor hot conditions. That is, by maintaining a reasonable and relatively constant contact force between the outer ring and the cylinder wall, the lifespan of the piston ring 15 is extended.

[0085] Example 5:

[0086] This embodiment is a further refinement of embodiment 4:

[0087] The stacked structure is configured such that, along the axial direction of the piston rod 3, adjacent outer ring end faces are in contact with each other, adjacent inner ring end faces are in contact with each other, and the inner end faces of the guide rings 17 at both ends of the stacked structure are in contact with the outer ring and the inner ring.

[0088] The above provides a more specific structural form of piston assembly 2. In this solution, the outer rings are fitted together, the inner rings are fitted together, and the guide ring 17 at the end of the stacked structure is fitted together with the outer rings and the inner rings. This makes the first piston assembly 21 and the second piston assembly 22 both multi-layer structures with stable layer-to-layer structure and relative position. Such a multi-layer structure can effectively ensure the performance reliability of piston assembly 2 from the perspective of overall vibration and interlayer slip angle.

[0089] Example 6:

[0090] This embodiment is a further refinement of embodiment 4:

[0091] The inner ring includes a sleeve 24 and multiple plate rings 20 in the shape of plates. The central hole is a channel on the sleeve 24. The plate rings 20 are arranged at intervals in the axial direction of the sleeve 24. The plate rings 20 are all sleeved on the sleeve 24 and welded to the sleeve 24 through a circumferential weld.

[0092] The inner wall of the outer ring is provided with annular grooves 12 in the same number as the plate rings 20. The annular grooves 12 are arranged at intervals on the axis of the outer ring. The outer edge of the plate ring 20 is embedded in the annular grooves 12, and each annular groove 12 is matched with a plate ring 20.

[0093] The above provides a specific implementation of the inner ring. The sleeve 24 serves as the connecting skeleton inside the plate ring 20 and provides a central hole for fitting the inner ring onto the piston rod 3. The plate ring 20 serves as a support ring between the outer ring and the sleeve 24. The ring weld is preferably formed by laser welding to ensure the axial sealing of the weld position through welding quality and reduce the impact of welding heat on material reliability. In this solution, compared to the length of the sleeve 24, the plate ring 20 is a thin-walled ring on the inner ring. This thin-walled ring is used to provide support for the inner side of the outer ring. When the temperature of the cylinder block 1 structure increases, the temperature of the plate ring 20 increases synchronously. The thinner plate ring 20 is more likely to undergo conical deformation under the compression of the outer ring expansion and its own expansion. Compared to a single plate ring 20 with the same thickness as the sleeve 24, the inner ring has less rigid constraint on the outer ring, thereby achieving the purpose of controlling the contact force between the outer ring and the cylinder wall. In this scheme, the plate ring 20 is connected to the outer ring by embedding the outer edge of the plate ring 20 into the annular groove 12 on the inner wall of the outer ring. The aim is to achieve the following: not only does the outer ring achieve positional constraint in the axial direction of the inner ring through a simple structure, but also, for hydrogen, even a small leakage gap can easily lead to hydrogen leakage. By embedding the outer edge of the plate ring 20 into the annular groove 12, the length of the gas leakage gap between the inner ring and the outer ring can be effectively increased, reducing the possibility of axial leakage of gas through the gap between the inner ring and the outer ring.

[0094] Example 7:

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

[0096] The gaps between the plate rings 20 and between the plate rings 20 and the guide ring 17 are filled with flexible filler layers 18.

[0097] In the above scheme, on the one hand, the flexible packing layer 18 is used to fill the gaps at the corresponding positions, so that the side of the plate ring 20 has support from the flexible packing. In this way, during the reciprocating motion and speed change motion of the piston assembly 2, the flexible packing layer 18 can effectively constrain the vibration occurring on the plate ring 20, thereby achieving the purpose of optimizing the stability of the piston ring 15. On the other hand, the flexible packing layer 18 is used to fill part of the space in the gap to reduce the air gap in the gap, so as to reduce the impact of the gas in the air gap on the structural stability and sealing reliability of the piston assembly 2 due to expansion and contraction. Preferably, due to the working temperature of the cylinder block 1 structure, the flexible packing layer 18 itself will also undergo a certain degree of thermal expansion. In order to avoid the impact of thermal expansion on the overall shape of the piston assembly 2 and the contact force with the cylinder wall, it is set that: the flexible packing layer 18 fills part of the space in the gap and / or the flexible packing layer 18 is made of a material with internal voids. With this scheme, the gap not filled by the flexible packing layer 18 forms an air gap and serves as the expansion space of the flexible packing layer 18. The voids allow the flexible packing layer 18 itself to be compressible. Preferably, the flexible filler layer 18 is made of flexible graphite material or expanded PTFE material with good resilience and long-term reliability in the operating temperature range of the cylinder block 1 structure. The flexible filler layer 18 is not suitable for rubber materials that are prone to failure under high temperature and hydrogen influence.

[0098] Example 8:

[0099] This embodiment is a further refinement of embodiment 1:

[0100] The cylinder body 1 has a double-layer structure with a bushing 13 on the inner side and an outer cylinder on the outer side. A cold water tank 14 for introducing cooling water into the cylinder body 1 is formed between the outer wall of the bushing 13 and the inner wall of the outer cylinder.

[0101] The above solution provides a specific form of cylinder block 1. In the specific solution, the bushing 13 is made of hydrogen embrittlement resistant material and provides a smooth cylinder wall. The cold water tank 14 is specifically used to control the temperature of the cylinder block 1 structure by introducing circulating cooling water into it. The cylinder block 1 with a double-layer structure is convenient to form a cold water tank 14 with a spiral structure.

[0102] Example 9:

[0103] Based on Embodiment 1, this embodiment provides a volumetric hydrogen compressor system, including a drive motor, a middle body 5, and a cylinder 1 structure. The drive motor is connected to the piston rod 3 of the cylinder 1 structure through the middle body 5. The middle body 5 is used to convert the rotational motion of the drive motor into the linear reciprocating motion of the piston rod 3. The cylinder 1 structure is the cylinder 1 structure described in Embodiment 1.

[0104] The above compressor system is a specific application of the cylinder body 1 structure, that is, the compressor system includes the cylinder body 1 structure. As those skilled in the art, the drive motor serves as the power source of this system. The power output by the drive motor is transmitted to the piston rod 3 through the middle body 5 and drives the piston rod 3 to perform linear reciprocating motion, and the gas is compressed in the cylinder body 1 structure.

[0105] Example 10:

[0106] This embodiment is a further refinement of embodiment 9:

[0107] It also includes a connecting plate 23, which includes a connecting plate and multiple reinforcing bars connected to the connecting plate. The reinforcing bars are arranged at intervals in the circumferential direction of the connecting plate. The pressure cylinder 4 is a cylindrical structure with a bottom plate at one end and an open end at the other end. The open end of the pressure cylinder 4 is bolted to the connecting plate through a flange on its outer side. The reinforcing bars are bolted to the shell of the middle body 5.

[0108] It also includes a processing module. The signal output terminal of the pressure sensor 8 is connected to the signal input terminal of the processing module. The processing module is configured to: collect the pressure measurement result of the pressure sensor 8 and compare it with a preset pressure threshold and a preset pressure rise rate threshold. When it is determined that the pressure measurement result is greater than or equal to the pressure threshold, or the pressure rise rate is greater than or equal to the pressure rise rate threshold, the piston assembly 2 wear abnormality determination result is output.

[0109] The above scheme provides a specific connection method for the pressure-collecting cylinder 4. Specifically, for the pressure-collecting cylinder 4 implementation mentioned above, which isolates the first pressure-collecting chamber 9 and the second pressure-collecting chamber 10 through the partition 19, the open end of the pressure-collecting cylinder 4 is used to complete the configuration and maintenance of the first sealing component. Regarding the end plate, the bottom plate serves as the end plate at one end of the pressure-collecting cylinder 4, and the second sealing component of this end plate is configured on the outside of the bottom plate. The connecting plate serves as the end plate at the other end of the pressure-collecting cylinder 4, and the second sealing component of this end plate is configured on the outside of the connecting plate. The connecting plate 23 serves as the intermediate connection structure between the pressure-collecting cylinder 4 and the middle body 5. The connecting plate 23 is configured to include multiple ribs spaced apart in the circumferential direction of the connecting plate, aiming to utilize the space between the ribs to adjust and maintain the second sealing component on the outside of the connecting plate. The processing module is used to collect the pressure measurement results of the pressure sensor 8 and, based on the pressure threshold and the pressure rise rate threshold, determine whether the piston assembly 2 has experienced abnormal wear.

[0110] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A cylinder structure for a positive displacement hydrogen compressor, comprising a cylinder (1), a piston assembly (2) installed in the cylinder (1), and a piston rod (3) connected to the piston assembly (2), characterized in that, The piston assembly (2) includes a first piston assembly (21) and a second piston assembly (22). The first piston assembly (21) and the second piston assembly (22) are installed on the piston rod (3) at intervals. Both the first piston assembly (21) and the second piston assembly (22) include piston rings (15) and guide rings (17). The piston rod (3) is provided with an air guide hole (11), and an annular groove (12) is formed between the first piston assembly (21) and the second piston assembly (22). One end of the air guide hole (11) is connected to the annular groove (12). It also includes a pressure-collecting cylinder (4), which has a closed cavity. The piston rod (3) passes through the pressure-collecting cylinder (4) and through the cavity. The other end of the air guide hole (11) is configured such that when the piston assembly (2) is in the gas compression stroke, the other end of the air guide hole (11) communicates with the cavity. It also includes a pressure sensor (8) installed on the pressure sampling cylinder (4) for measuring the pressure in the cavity; The pressure-collecting cylinder (4) is a cylindrical structure with its axis parallel to the axis of the piston rod (3), end plates at both ends, and a partition (19) in the center. The cavity includes a first pressure-collecting chamber (9) and a second pressure-collecting chamber (10) separated by the partition (19). The piston rod (3) passes through the partition (19) and the end plates at both ends of the pressure cylinder (4). The partition (19) is equipped with a first sealing assembly that achieves axial sealing of the gap between its upper channel and the piston rod (3). The end plates are each equipped with a second sealing assembly that achieves axial sealing of the gap between their respective upper channels and the piston rod (3). The first pressure sampling chamber (9) and the second pressure sampling chamber (10) are each equipped with a pressure sensor (8) for measuring the pressure in their respective chambers; Both ends of the cylinder (1) are provided with an air inlet (7) and an exhaust outlet (6); The first pressure chamber (9) and the second pressure chamber (10) are configured such that: during the reciprocating motion of the piston assembly (2) in the cylinder (1), when the piston assembly (2) compresses the gas on one side of the cylinder (1), the air guide hole (11) communicates with one of the first pressure chamber (9) and the second pressure chamber (10), and when the piston assembly (2) compresses the gas on the other side of the cylinder (1), the air guide hole (11) communicates with the other one of the two.

2. The cylinder block structure of a positive displacement hydrogen compressor according to claim 1, characterized in that, The first sealing component is a sealing ring installed in the annular groove of the channel on the partition plate (19). The number of the sealing rings is greater than or equal to 3, and each sealing ring is equipped with an independent annular groove. The second sealing component is a packing sealing component installed on the end plate. The packing sealing component includes packing and a pressure ring for pressing the packing. The packing is set in the packing box of the end plate. The pressure ring is connected to the end plate by a pressure bolt. The end of the pressure ring acts on the packing.

3. The cylinder block structure of a positive displacement hydrogen compressor according to claim 1, characterized in that, The first piston assembly (21) and the second piston assembly (22) are both configured to include multiple piston rings (15), the piston rings (15) being stacked in the axial direction of the piston rod (3), the guide rings (17) being fixed on the piston rod (3), and the stacked structure formed by the stacking is provided with guide rings (17) at both ends, and the stacked structure is sandwiched between the guide rings (17); The piston ring (15) is a plate-shaped structure including an outer ring and an inner ring. The outer ring is a polymer material ring, and the inner ring is a metal plate (16) with a central hole. The inner ring is sleeved on the piston rod (3) through the central hole thereon. The outer ring is fixed on the outer edge of the inner ring and the outer ring is in contact with the cylinder wall of the cylinder body (1).

4. The cylinder block structure of a positive displacement hydrogen compressor according to claim 3, characterized in that, The stacked structure is configured such that, in the axial direction of the piston rod (3), the adjacent outer ring end faces are in contact with each other, the adjacent inner ring end faces are in contact with each other, and the inner end faces of the guide rings (17) at both ends of the stacked structure are in contact with the outer ring and the inner ring.

5. The cylinder block structure of a positive displacement hydrogen compressor according to claim 3, characterized in that, The inner ring includes a sleeve (24) and multiple plate rings (20) in the shape of plates. The central hole is a channel on the sleeve (24). The plate rings (20) are arranged at intervals in the axial direction of the sleeve (24). The plate rings (20) are all sleeved on the sleeve (24) and welded to the sleeve (24) by a circumferential weld. The inner wall of the outer ring is provided with an annular grooves of the same number as the plate rings (20). The annular grooves are arranged at intervals on the axis of the outer ring. The outer edge of the plate ring (20) is embedded in the annular grooves, and each annular groove is matched with a plate ring (20).

6. The cylinder block structure of a positive displacement hydrogen compressor according to claim 5, characterized in that, The gaps between the plate rings (20) and between the plate rings (20) and the guide ring (17) are filled with flexible filler layers (18).

7. A cylinder block structure for a positive displacement hydrogen compressor according to any one of claims 1 to 6, characterized in that, The cylinder (1) has a double-layer structure with a bushing (13) on the inner side and an outer cylinder on the outer side. A cold water tank (14) for introducing cooling water into the cylinder (1) is formed between the outer wall of the bushing (13) and the inner wall of the outer cylinder.

8. A positive displacement hydrogen compressor system, comprising a drive motor, a central body (5), and a cylinder structure, wherein the drive motor is connected to a piston rod (3) of the cylinder structure via the central body (5), and the central body (5) is used to convert the rotational motion of the drive motor into the linear reciprocating motion of the piston rod (3), characterized in that, The cylinder structure is the cylinder structure described in any one of claims 1 to 7.

9. A positive displacement hydrogen compressor system according to claim 8, characterized in that, It also includes a connecting plate (23), which includes a connecting plate and multiple reinforcing bars connected to the connecting plate. The reinforcing bars are arranged at intervals in the circumferential direction of the connecting plate. The pressure cylinder (4) is a cylindrical structure with a bottom plate at one end and an open end at the other end. The open end of the pressure cylinder (4) is bolted to the connecting plate through a flange on its outer side. The reinforcing bars are bolted to the shell of the middle body (5). It also includes a processing module. The signal output terminal of the pressure sensor (8) is connected to the signal input terminal of the processing module. The processing module is configured to: collect the pressure measurement result of the pressure sensor (8) and compare it with the preset pressure threshold and the preset pressure rise rate threshold. When it is determined that the pressure measurement result is greater than or equal to the pressure threshold, or the pressure rise rate is greater than or equal to the pressure rise rate threshold, the piston assembly (2) wear abnormality determination result is output.

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