Piston seal assembly and method for an ultra-high pressure liquid injection compressor

Abstract

The application discloses a piston sealing assembly and method of an ultrahigh-pressure liquid-drive compressor, which comprises a sealing assembly in an annular structure and sleeved on a piston through an annular groove, a plurality of supporting members and a plurality of sealing members, which are alternately sleeved into the annular groove to form a multiple sealing structure, and the contact surfaces of the adjacent supporting members and sealing members are arranged in close contact and are concave in the direction of gas pressure; wherein the inner and outer ring surfaces of the sealing members are both conical surfaces, the outer ring surface of the sealing member at the front end surface is in interference fit with the cylinder barrel, and the outer ring surface at the rear end surface is in clearance fit with the cylinder barrel; the inner and outer ring surfaces of the supporting member are both cylindrical surfaces, the outer ring surface is in clearance fit with the cylinder barrel, and the inner and outer ring distance is greater than the inner and outer ring distance of the sealing member at the rear end surface. The multiple sealing assembly is adopted to disperse the pressure bearing of the single sealing member, the curved surface design and the connecting structure between the different sealing members and supporting members are matched, and the sealing effect and durability of the compressor piston are improved.

Description

Technical Field

[0001] This invention relates to the field of ultra-high pressure piston technology. More specifically, this invention relates to a piston sealing assembly and method for an ultra-high pressure hydraulically driven compressor. Background Technology

[0002] In the research of ultra-high pressure hydraulically driven compressors, cylinder piston sealing technology plays a crucial role in compressor performance and is both a key focus and a challenge in hydraulically driven compressor technology research. However, due to its relatively short application time, there is currently limited publicly available research on sealing structures, methods, and materials under ultra-high pressure. Especially under ultra-high pressure conditions of 105 MPa, the gas pressure is directly applied to the contact surface between the seal and the cylinder, generating significant friction and easily leading to uneven wear. This makes it difficult to guarantee the sealing effect of the seal and severely shortens its service life.

[0003] To address the aforementioned issues, it is necessary to design a piston sealing assembly and method for an ultra-high pressure hydraulically driven compressor to improve the effectiveness and durability of the compressor piston seal. Summary of the Invention

[0004] The purpose of this invention is to provide a piston sealing assembly and method for an ultra-high pressure hydraulically driven compressor. The invention employs multiple sealing assemblies to distribute the pressure of individual seals, and combines the curved surface design and connection structure between different seals and support components to improve the sealing effect and durability of the compressor piston.

[0005] To achieve these objectives and other advantages according to the present invention, a piston sealing assembly for an ultra-high pressure hydraulically driven compressor is provided, comprising:

[0006] A sealing assembly, which is an annular structure and is fitted onto the piston through a pre-set annular groove, includes multiple support members and multiple sealing members. The support members and the sealing members are alternately fitted into the annular groove along the axial direction to form a multiple sealing structure. The contact surfaces of adjacent support members and sealing members are fitted together and recessed backward along the gas pressure direction. Both ends of the sealing assembly are set as support members, which respectively abut against the two ends of the annular groove.

[0007] The inner and outer ring surfaces of the seal are both conical and coaxially arranged. The outer ring surface of the seal at the front end face is press-fitted with the cylinder, and the outer ring surface of the seal at the rear end face is clearance-fitted with the cylinder. The inner and outer ring surfaces of the support are both cylindrical and coaxially arranged. The outer ring surface of the support at either end face is clearance-fitted with the cylinder, and the distance between the inner and outer rings is greater than the distance between the inner and outer rings of the seal at the rear end face.

[0008] Preferably, in the piston sealing assembly of the ultra-high pressure hydraulic compressor, the contact surfaces of the seal and the support are both curved surfaces with the inner arc surface facing the front end in the direction of gas pressure, and their axial cross-section is symmetrical along the central axis of the inner and outer ring surfaces of the seal.

[0009] The sealing element has two concave sides on its front end face that are recessed in the direction of gas pressure to form a first conical surface. The rear ends of the two first conical surfaces are further recessed in the direction of gas pressure and connect at the central axis to form a first arc surface. The sealing element has two concave sides on its rear end face that are recessed in the direction of gas pressure and connect at the central axis to form a second arc surface. The front end face of the support member is adapted to and fits the rear end face of the sealing element. The rear end face of the support member is adapted to and fits the front end face of the sealing element.

[0010] Preferably, the piston sealing assembly of the ultra-high pressure hydraulic compressor further includes two pressure rings, which are respectively disposed at both ends of the sealing assembly. Each pressure ring is engaged between the sealing assembly and the annular groove. One end of the pressure ring is engaged with the end of the adjacent annular groove, and the other end is adapted to and fitted with the end face shape of the adjacent support member.

[0011] Preferably, in the piston sealing assembly of the ultra-high pressure hydraulic compressor, the contact surface between the pressure ring near the cylinder end and the adjacent support member is a second conical surface that is wider at the front and narrower at the back, and an annular mounting groove is provided at the contact surface between the second conical surface and the piston; the piston sealing assembly of the ultra-high pressure hydraulic compressor also includes a sealing ring, which is engaged between the piston and the pressure ring and the support member through the annular mounting groove.

[0012] Preferably, the piston sealing assembly of the ultra-high pressure hydraulic compressor further includes a pre-tightening device, which is disposed between the pressure ring near one end of the cylinder and the end of the adjacent annular groove. The pre-tightening device includes two supports, which are spaced apart and sleeved on the annular groove. The support at the front end abuts against the end of the adjacent annular groove, and the support at the rear end abuts against the front end face of the adjacent pressure ring. An elastic element is disposed between the two supports along the length direction of the piston and is fixedly connected to them.

[0013] Preferably, in the piston sealing assembly of the ultra-high pressure hydraulic compressor, the annular groove includes a stepped groove and a flat groove, which are continuously disposed on the piston along the gas pressure direction. The flat groove is located at the rear end in the gas pressure direction and the depth of each position in the groove is equal. The stepped groove extends forward from the front end face of the flat groove and is recessed in the direction of the piston axis to form a multi-stage stepped structure, and its front end is connected to the inside of the cylinder.

[0014] The piston sealing assembly of the ultra-high pressure hydraulic compressor also includes a retaining ring. The sealing assembly is engaged in the flat groove and abuts against its end away from the cylinder. The retaining ring is engaged in the stepped groove and abuts against the end of the adjacent sealing assembly.

[0015] This invention also provides a piston sealing method for an ultra-high pressure hydraulically driven compressor, comprising:

[0016] S1. A coaxial annular groove is made at the end of the piston near the cylinder.

[0017] S2. Fit the sealing ring into the flat groove of the annular groove according to the set position;

[0018] S3. According to the set sequence, multiple support members, multiple sealing members and two pressure ring members are respectively axially fitted into the rear part of the flat groove, so that the pressure ring member away from the cylinder abuts against the rear end of the flat groove, and the pressure ring member near the cylinder end and the annular mounting groove between the support member and the sealing ring are engaged.

[0019] S4. Install the pre-tightening device at the front of the flat groove so that the support at the rear end abuts against the adjacent pressure ring.

[0020] S5. Insert the snap ring into the stepped groove of the annular groove, so that the rear end face of the snap ring abuts and presses against the support located at the front end.

[0021] The present invention has at least the following beneficial effects:

[0022] 1. This invention reduces the pressure borne by a single seal by setting up a multi-seal structure, thereby reducing the pressure on the single-stage seal during compressor operation, significantly reducing the wear rate of the seal, increasing the reliability and sealing effect of the sealing structure, and improving the sealing effect and durability of the compressor piston by combining the curved surface design and connection structure between different seals and support components.

[0023] 2. This invention provides front and rear guide and support structures for the sealing assembly, ensuring stable positioning of the piston main seal and guaranteeing the coaxiality of the sealing assembly as it moves linearly with the piston within the compressor cylinder. This avoids problems such as uneven wear of the seals, extending the service life of the seals and further improving the effectiveness and durability of the compressor sealing assembly. It also enhances the adaptability of the sealing assembly to oil-free sealing environments, making it suitable for a wider range of compressor types and operating conditions, and showing promising application prospects in the field of liquid-driven compressors.

[0024] Other advantages, objectives and features of the present invention will become apparent in part from the following description, and in part from those skilled in the art through study and practice of the invention. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the axial cross-sectional structure of a piston sealing assembly of an ultra-high pressure hydraulic compressor according to an embodiment of the present invention.

[0026] Figure 2 This is a schematic diagram of the axial cross-sectional structure of the seal described in the above embodiments;

[0027] Figure 3 This is a schematic diagram of the axial cross-sectional structure of the support member described in the above embodiments.

[0028] Explanation of reference numerals in the attached figures:

[0029] 1. Seal; 2. Support; 3. Pressure ring; 41. Support; 42. Elastic element; 43. Snap ring; 44. Screw; 5. Sealing ring; 6. Piston axis; 71. First conical surface; 72. First arc surface; 73. Second arc surface; 74. Second conical surface; 81. Conical surface; 82. Cylindrical surface. Detailed Implementation

[0030] The present invention will now be described in further detail with reference to the accompanying drawings, so that those skilled in the art can implement it based on the description.

[0031] It should be noted that, unless otherwise specified, the experimental methods described in the following embodiments are all conventional methods, and the reagents and materials described are all commercially available unless otherwise specified. In the description of this invention, the terms "lateral", "longitudinal", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0032] like Figure 1-3 As shown, the present invention provides a piston sealing assembly for an ultra-high pressure hydraulically driven compressor, comprising:

[0033] A sealing assembly, which is an annular structure and is fitted onto the piston through a pre-set annular groove, includes multiple support members 2 and multiple sealing members 1. The support members 2 and the sealing members 1 are alternately fitted into the annular groove along the axial direction to form a multiple sealing structure. The contact surfaces of adjacent support members 2 and sealing members 1 are fitted together and recessed backward along the gas pressure direction. Both ends of the sealing assembly are set as support members, which respectively abut against the two ends of the annular groove.

[0034] The inner and outer ring surfaces of the seal are both conical surfaces 81 and are coaxially arranged. The outer ring surface of the seal at the front end face is interference-fitted with the cylinder, and the outer ring surface of the seal at the rear end face is clearance-fitted with the cylinder. The inner and outer ring surfaces of the support are both cylindrical surfaces 82 and are coaxially arranged. The outer ring surface of the support at either end face is clearance-fitted with the cylinder, and the distance between the inner and outer rings is greater than the distance between the inner and outer rings of the seal at the rear end face.

[0035] In the above technical solution, the sealing assembly is integrally sleeved on the piston, and the sealing assembly is located between the piston and the compressor cylinder. When the piston moves linearly along the inner wall of the cylinder, the sealing assembly moves synchronously with the piston. Because it is engaged with the piston through an annular groove, there is no relative sliding between the integral sealing assembly and the piston, ensuring the reliability and effectiveness of the seal. The installation direction of the piston sealing assembly of the ultra-high pressure hydraulic compressor is set as follows: front ( Figure 1 (Left side) facing the compressor end cover, rear ( Figure 1 (Right side) Facing the piston rod, during gas compression, pressure is applied axially from the front to the rear of the sealing assembly (piston), i.e., the gas pressure direction is from front to back along the piston axis 6. Multiple supports and seals can be provided. A seal is provided between any two adjacent supports. The seal, while acting as the main seal to close the gap between the piston and cylinder, also closes the gap between two adjacent supports, connecting them as a whole. The specific number of supports and seals can be selected and adjusted according to different compressor operating conditions. Regardless of the specific number selected, since stable support is required at both ends of all seals, the total number of supports needs to be one more than the number of seals. This avoids contact between the seals and the ends of the annular groove, forming a stable support structure while ensuring that the seals are not easily damaged, improving the stability of the sealing assembly. In this embodiment, the number of supports is set to three, and correspondingly, the number of seals required between two adjacent supports is two. Both the seals and supports are annular structures, with their inner annular surfaces engaging with the annular grooves on the outer wall of the piston, and their outer annular surfaces mating with the inner wall of the cylinder. Among them, the seals play the role of main sealing, and the supports are set at both ends of each seal to provide support, guidance and limit for the middle seals, thus playing an auxiliary sealing role. The seals and supports are staggered along the piston axis 6 on the annular groove on the outside of the piston to form a multi-seal structure. Adjacent seals and supports are fitted together to form an annular contact surface. The axial cross section of this contact surface at any position in the circumferential direction is a curved surface that is concave backward along the gas pressure direction (i.e., concave from front to back).

[0036] Specifically, such as Figure 2As shown, the inner and outer ring surfaces of the seal are coaxial, spaced-apart conical surfaces, with the vertices of the two conical surfaces facing opposite directions (in the gas pressure direction). Taking an axial cross-section of the seal, the conical surface corresponding to the outer ring surface is inclined towards the piston axis 6 in the gas pressure direction, while the conical surface corresponding to the inner ring surface is inclined away from the piston axis 6 in the gas pressure direction. The two conical surfaces are symmetrically arranged relative to the centerlines (vertically and vertically) of the inner and outer ring surfaces, which facilitates pressure bearing from the center of the stress surface to both sides. For the seal, its cross-section forms a sealing structure that is wider at the front and narrower at the back, meaning the thickness at the front end (in the height direction of the figure) is greater than the thickness at the rear end. Simultaneously, the inner and outer ring surfaces of the support are both designed as conventional cylindrical structures to better fit the piston and cylinder sidewalls. The thickness of the support (i.e., the distance between its inner and outer rings) is set to be less than the thickness of the seal at the front end but greater than the thickness of the seal at the rear end. Because the support and cylinder are connected with a clearance fit, and the outer annular surface of the front end face of the seal is connected with the cylinder with an interference fit, the structural design of the sealing assembly creates a more reasonable sealing and support structure between the seal and the support. Gas pressure from the cylinder direction acts on the end face of the main seal, pressing it towards the support. During this pressing process, the gap between the rear end face of the seal and the cylinder allows for deformation of the seal within a certain range. The support provides full coverage support to the rear end face of the seal, and its thickness is greater than the thickness of the seal at the rear end face. This support can adapt to the deformation of the seal during the compression process, and effectively buffer the pressure through the concave curved surface connection structure between the support and the seal. The pressure that has not been buffered / unloaded is loaded backward to another set of seals and supports for secondary buffering / unloading. The above-mentioned multi-seal structure can better assist in bearing pressure. The entire sealing assembly transmits the gas pressure to the main seal (seal) through interaction force, so that the force between the seal and the cylinder wall is higher than the gas pressure. Thus, the adaptability of the sealing assembly under high pressure environment is greatly improved and the sealing reliability is guaranteed. Furthermore, the curved surface connection structure of the support and seal improves the connection stability between the seal and the support without changing or adding to the overall structure of the sealing assembly. The curved surface structure, which is concave along the gas pressure direction, provides relative positioning of the seal and the support from multiple directions, ensuring stable positioning of the piston main seal. This guarantees the coaxiality of the sealing assembly as it moves linearly with the piston within the compressor cylinder, thus avoiding problems such as uneven wear of the seal and extending its service life. This improves the effectiveness and durability of the compressor sealing assembly, while also enhancing its adaptability to oil-free sealing environments. This allows it to be applied to a wider range of compressor types and different operating conditions, showing promising application prospects in the field of liquid-driven compressors.

[0037] In another technical solution, the piston sealing assembly of the ultra-high pressure hydraulic compressor has a sealing element and a support element whose contact surfaces are both curved surfaces with the inner arc surface facing the gas pressure direction, and whose axial cross section is symmetrical along the central axis of the inner and outer ring surfaces of the sealing element.

[0038] Specifically, the front end face of the seal is first recessed along the gas pressure direction on both sides to form a first conical surface 71. The rear ends of the two first conical surfaces continue to be recessed along the gas pressure direction and connect at the central axis to form a first arc surface 72. The rear end face of the seal is recessed along the gas pressure direction on both sides and connect at the central axis to form a second arc surface 73. The front end face of the support is adapted to and fits the rear end face of the seal. The rear end face of the support is adapted to and fits the front end face of the seal.

[0039] In the above technical solution, the central axis between the inner and outer annular surfaces of the seal is... Figure 2 The centerline between the inner and outer annular surfaces on the axial cross-section of the sealing element is defined by the sealing element's front end face, which is a curved surface formed by the first conical surface and the first arc surface, symmetrical about the central axis (top and bottom). The rear end face is a curved surface formed by the second arc surface, also symmetrical about the central axis. This, combined with the tapered cross-section (wider at the front and narrower at the back) formed between the inner and outer annular surfaces, further optimizes the sealing element's stress structure. According to stress structure analysis and experimental data, when the two first conical surfaces of the sealing element are set at 90°, the radius of curvature of the first arc surface is 2-5 mm, and the radius of curvature of the second arc surface is 4-7 mm, better sealing effect and durability can be achieved. In this embodiment, the distance between the inner and outer rings of the seal at the front end face is 20.2 mm, and the distance between the inner and outer rings at the rear end face is 19.8 mm. The distance between the inner and outer rings of the support member is 20 mm. The two first conical surfaces are set at 90°, the radius of curvature of the first arc surface is 3.5 mm, and the radius of curvature of the second arc surface is 5.2 mm. Figure 3 As shown, the front and rear end face shapes of the support are determined according to the end face shape of the seal it supports. The support shown is placed between two seals. The front end face shape of the support is adapted to and fits the rear end face shape of the previous seal, and the rear end face shape of the support is adapted to and fits the front end face shape of the next seal, thereby achieving better support, guidance, limiting and buffering effects.

[0040] Sealing component performance test: The sealing component in this embodiment and another sealing component with a conventional structure (the contact surfaces of each seal and support are flat, but the number and thickness are the same as in this embodiment) are installed on the outer annular groove of the piston of the same specification, and the sealing durability test is carried out on the two pistons to verify their sealing performance.

[0041] Specifically, a piston is installed in a booster cylinder, and the piston is hydraulically driven to reciprocate within the cylinder. A helium-based pressurization-depressurization test is then performed: the outlet gas pressure of the booster cylinder is maintained at 105 MPa, and the inlet gas pressure is 45 MPa. The pressurized gas circulates in the pipeline, undergoing pressurization and depressurization. A gas flow meter behind the piston is used to detect leaks, and a leakage reading exceeding 0.17 L / min is used to determine the service life of the sealing assembly. The service life of a conventionally assembled sealing assembly is approximately 800 hours, while the service life of the sealing assembly in this embodiment is 6000 hours. Therefore, under ultra-high pressure operating conditions, using the sealing assembly of this invention on the compressor piston ensures sealing effectiveness while significantly extending the seal's service life, avoiding seal failure and the need for frequent replacement of the sealing assembly.

[0042] In another technical solution, the piston sealing assembly of the ultra-high pressure hydraulic compressor further includes two pressure rings 3, which are respectively disposed at both ends of the sealing assembly. Each pressure ring is engaged between the sealing assembly and the annular groove. One end of the pressure ring is fitted to the end of the adjacent annular groove, and the other end is adapted to and fitted to the end face shape of the adjacent support member. However, since the support members at both ends of the sealing assembly need to abut against both ends of the annular groove, but according to the structural design of the support members, the front and rear end face shapes need to match the end face shape of the sealing assembly, there are problems such as inability to fit properly when the support members directly abut against the end of the annular groove, which can easily cause unstable positioning or damage to the support members. To ensure the stability of the fit between the support members and the annular groove, pressure rings are provided at both ends of the sealing assembly to adapt to the end face shape of the support members located at the ends. The other end of the pressure ring can fit against the end face of the groove, ensuring the stability of the entire sealing assembly fixed within the annular groove. Each pressure ring is designed as a ring structure and can be fitted onto the annular groove of the piston together with the sealing assembly. To ensure that the gas pressure acts smoothly on the main seal without affecting the reciprocating motion of the piston in the cylinder, the outer ring surface of the pressure ring is gap-connected to the inner wall of the cylinder. Simultaneously, the pressure ring also serves to transmit and support force, and can compress the support and sealing components inward from both ends through the limitation of the installation position (on the piston), providing a certain preload force to the main and auxiliary sealing structures, thus better integrating the sealing assembly into a whole and further ensuring the integrity and sealing stability of the sealing assembly.

[0043] In another technical solution, the piston sealing assembly of the ultra-high pressure hydraulic compressor has a second conical surface 74, wider at the front and narrower at the back, where the pressure ring near the cylinder end contacts the adjacent support. An annular mounting groove is provided at the contact surface between the second conical surface and the piston. The piston sealing assembly also includes a sealing ring 5, which is secured between the piston, the pressure ring, and the support via the annular mounting groove. The sealing ring is positioned between the sealing assembly and the piston (annular groove) to seal the inner connection surface of the sealing assembly, further preventing fluid exchange between the cavities on both sides of the piston. To ensure the sealing effect is not affected by the internal pressure transmission structure of the sealing assembly, the pressure ring at the front end (near the cylinder end) is connected to the support via a conical surface, and an annular mounting groove is provided at the connection between the conical surface and the piston. During positioning and installation, the sealing ring can be secured within the annular mounting groove, facilitating positioning and installation between the sealing ring and the sealing assembly. After installation, the sealing ring, the annular mounting groove, and the piston are all interference-fitted to ensure a good sealing effect.

[0044] In another technical solution, the piston sealing assembly of the ultra-high pressure hydraulic compressor further includes a pre-tightening device, which is disposed between the pressure ring near one end of the cylinder and the end of the adjacent annular groove. The pre-tightening device includes two supports 41, which are spaced apart and sleeved on the annular groove. The support at the front end abuts against the end of the adjacent annular groove, and the support at the rear end abuts against the front end face of the adjacent pressure ring. An elastic element 42 is disposed between the two supports along the length of the piston and is fixedly connected to them. The supports are annular sleeve structures fixed to the piston, with an L-shaped axial cross-section. The two supports are symmetrically arranged on the piston, with the horizontal part of one support fitting against the outer wall of the piston, and the vertical parts of the two supports connected by the elastic element. The elastic element can be a spring, which is entirely sleeved on the annular groove of the piston. The distance between the two supports is less than the free length of the spring, meaning the elastic element is in a compressed state after installation. The pre-tightening device is located at the front end of the overall sealing assembly. In the initial state, the pre-tightening device has a pre-tightening pressure from the inside to the outside. After being assembled with the sealing assembly behind it, it can provide additional initial pre-tightening force. At the same time, it works with the pressure ring structure to simultaneously compress the multi-layer seal from the inside and outside, further improving the sealing effect of the main seal.

[0045] In another technical solution, the piston sealing assembly of the ultra-high pressure hydraulic compressor includes an annular groove comprising a stepped groove and a flat groove, which are continuously disposed on the piston along the gas pressure direction. The flat groove is located at the rear end in the gas pressure direction and the depth of each position in the groove is equal. The stepped groove extends forward from the front end face of the flat groove and is recessed in the direction of the piston axis to form a multi-stage stepped structure, and its front end is connected to the inside of the cylinder.

[0046] The piston sealing assembly of the ultra-high pressure hydraulic compressor also includes a retaining ring 43. The sealing assembly is engaged in the flat groove and abuts against its end away from the cylinder. The retaining ring is engaged in the stepped groove and abuts against the end of the adjacent sealing assembly.

[0047] In the above technical solution, the annular groove is set as two different shapes, front and rear, and connected to the front cylinder. On the one hand, the obstruction structure at the front end of the flat groove is removed, that is, the flat groove only has one end with a limiting function on the rear end face, and the front end face is connected to the further recessed stepped groove, which facilitates the sealing assembly to be fitted from the end on the same side of the piston. After the sealing assembly is installed, the step groove is locked with a snap ring to limit the sealing assembly. The snap ring 43 is made of two semi-circular ring structures spliced ​​together. After the splicing is completed, the upper and lower screws 44 are used to lock the semi-circular rings, which completes the installation and limiting of the entire sealing assembly on the piston. On the other hand, the above installation structure allows each annular structure (including the seal, support, pressure ring, support, etc.) in the sealing assembly to be made of rigid materials. It will not cause the problem of installation difficulty with the annular groove due to the sealing assembly's lack of elastic deformation, or the need to set a single annular structure as a split connection structure for installation. From the perspective of materials and installation structure, the sealing stability and durability of the sealing assembly are further guaranteed. In this embodiment, the materials used for processing the pressure ring and the support can be metal materials such as 316L, or polymer engineering plastics such as PEEK. The materials used for processing the seal can be self-lubricating modified material PTFE.

[0048] This invention also provides a piston sealing method for an ultra-high pressure hydraulically driven compressor, comprising:

[0049] S1. An annular groove is coaxially formed at the end of the piston near the cylinder. The annular groove includes a flat groove at the rear and a stepped groove at the front. The front end of the stepped groove is connected to the cylinder interior at the front end of the piston.

[0050] S2. Fit the sealing ring 5 into the flat groove of the annular groove according to the set position. The installation position of the sealing ring 5 is the connection between the annular mounting groove and the flat groove on the contact surface of the support member 2 near the cylinder end and the adjacent pressure ring member 3 after the sealing assembly is installed.

[0051] S3. According to the set sequence, multiple support members 2, multiple sealing members 1 and two pressure ring members 3 are respectively axially fitted into the rear part of the flat groove, so that the pressure ring member away from the cylinder abuts against the rear end of the flat groove, and the pressure ring member near the cylinder end and the annular mounting groove between the support member and the sealing ring 5 are engaged.

[0052] In this embodiment, the installation sequence of multiple support members, multiple seal members and two pressure ring members is pressure ring member-support member-seal member-support member-seal member-support member-seal member-support member-pressure ring member, and the installation direction is axial from the rear end of the flat groove to the front end;

[0053] S4. Install the pre-tightening device at the front of the flat groove so that the support 41 at the rear end abuts against the adjacent pressure ring 3. At this time, the support 41 at the front end is just set at the front end of the flat groove.

[0054] S5. Insert the retaining ring 43 into the stepped groove of the annular groove, so that the rear end face of the retaining ring 43 abuts and presses against the support 41 located at the front end. Specifically, insert the two semi-circular structures of the retaining ring into the two sides of the stepped groove and align them. Then, use two bolts to lock the pre-set mounting holes at the top and bottom of the two semi-circular structures, thus completing the fixed engagement of the retaining ring and the stepped groove. Under the constraint of the stepped structure of the stepped groove, the retaining ring cannot undergo relative displacement. At the same time, the end face of the retaining ring near the flat groove abuts against the support located at the front end of the pre-tightening device, realizing the overall limiting and pressing of the sealing component, pressure ring, and pre-tightening device in the flat groove. The outer walls of the pre-tightening device and the retaining ring have gaps with the inner wall of the cylinder to avoid affecting the normal operation of the piston and the sealing effect of the sealing component.

[0055] Although embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for the present invention. For those skilled in the art, other modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details and illustrations shown and described herein.

Claims

1. A piston sealing assembly for an ultra-high pressure hydraulically driven compressor, characterized in that, include: A sealing assembly, which is an annular structure and is fitted onto the piston through a pre-set annular groove, includes multiple support members and multiple sealing members. The support members and the sealing members are alternately fitted into the annular groove along the axial direction to form a multiple sealing structure. The contact surfaces of adjacent support members and sealing members are fitted together and recessed backward along the gas pressure direction. Both ends of the sealing assembly are set as support members, which respectively abut against the two ends of the annular groove. The sealing element has conical inner and outer ring surfaces that are coaxially arranged. The outer ring surface of the sealing element at the front end face is press-fitted with the cylinder, and the outer ring surface of the sealing element at the rear end face is clearance-fitted with the cylinder. The supporting element has cylindrical inner and outer ring surfaces that are coaxially arranged. The outer ring surface of the supporting element at either end face is clearance-fitted with the cylinder, and the distance between the inner and outer rings is greater than the distance between the inner and outer rings of the sealing element at the rear end face. The contact surfaces of the seal and the support are both curved surfaces with the inner arc facing the front end in the direction of gas pressure, and their axial cross-sections are symmetrical along the central axis of the inner and outer ring surfaces of the seal. The sealing element has two concave sides on its front end face that are recessed in the direction of gas pressure to form a first conical surface. The rear ends of the two first conical surfaces are further recessed in the direction of gas pressure and connect at the central axis to form a first arc surface. The sealing element has two concave sides on its rear end face that are recessed in the direction of gas pressure and connect at the central axis to form a second arc surface. The front end face of the support member is adapted to and fits the rear end face of the sealing element. The rear end face of the support member is adapted to and fits the front end face of the sealing element.

2. The piston sealing assembly of the ultra-high pressure hydraulically driven compressor as described in claim 1, characterized in that, It also includes two pressure rings, which are respectively disposed at both ends of the sealing assembly. Each pressure ring is engaged between the sealing assembly and the annular groove. One end of the pressure ring is connected to the end of the adjacent annular groove, and the other end is adapted to and fitted to the end face shape of the adjacent support member.

3. The piston sealing assembly of the ultra-high pressure hydraulically driven compressor as described in claim 2, characterized in that, The contact surface between the pressure ring near one end of the cylinder and the adjacent support is a second conical surface that is wider at the front and narrower at the back. An annular mounting groove is provided at the contact surface between the second conical surface and the piston. The piston sealing assembly of the ultra-high pressure hydraulic compressor also includes a sealing ring, which is engaged between the piston and the pressure ring and the support through the annular mounting groove.

4. The piston sealing assembly of the ultra-high pressure hydraulically driven compressor as described in claim 2, characterized in that, It also includes a pre-tightening device, which is disposed between the pressure ring near one end of the cylinder and the end of the adjacent annular groove. The pre-tightening device includes two supports, which are spaced apart and sleeved on the annular groove. The support at the front end abuts against the end of the adjacent annular groove, and the support at the rear end abuts against the front end face of the adjacent pressure ring. An elastic element is disposed between the two supports along the length direction of the piston and is fixedly connected to them.

5. The piston sealing assembly of the ultra-high pressure hydraulically driven compressor as described in claim 1, characterized in that, The annular groove includes a stepped groove and a flat groove, which are continuously arranged on the piston along the gas pressure direction. The flat groove is located at the rear end in the gas pressure direction and the depth of each position in the groove is equal. The stepped groove extends forward from the front end face of the flat groove and is recessed in the direction of the piston axis to form a multi-stage stepped structure. Its front end is connected to the inside of the cylinder. The piston sealing assembly of the ultra-high pressure hydraulic compressor also includes a retaining ring. The sealing assembly is engaged in the flat groove and abuts against its end away from the cylinder. The retaining ring is engaged in the stepped groove and abuts against the end of the adjacent sealing assembly.

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