CN115807755A - Piston sealing assembly and method for ultrahigh-pressure liquid-driven compressor - Google Patents

Abstract

The invention discloses a piston sealing assembly and a method of an ultrahigh pressure liquid-driven compressor, wherein the piston sealing assembly comprises the following components: the sealing assembly is of an annular structure, is sleeved on the piston through an annular groove, comprises a plurality of supporting pieces and a plurality of sealing pieces, is alternately sleeved in the annular groove along the axial direction to form a multi-sealing structure, and the contact surfaces of the adjacent supporting pieces and the sealing pieces are attached and arranged and are recessed backwards along the gas pressure direction; the inner ring surface and the outer ring surface of the sealing element are conical surfaces, the outer ring surface of the sealing element at the front end surface is in interference fit with the cylinder barrel, and the outer ring surface of the sealing element at the rear end surface is in clearance fit with the cylinder barrel; the inner ring surface and the outer ring surface of the supporting piece are cylindrical surfaces, the outer ring surface of the supporting piece is in clearance fit with the cylinder barrel, and the distance between the inner ring and the outer ring is larger than that between the inner ring and the outer ring of the sealing piece at the rear end surface. The invention adopts multiple sealing components to disperse the bearing of a single sealing element, and realizes the improvement of the sealing effect and the durability of the compressor piston by matching with curved surface designs and connecting structures among different sealing elements and supporting elements.

Description

Piston sealing assembly and method for ultrahigh-pressure liquid-driven compressor

Technical Field

The invention relates to the technical field of ultrahigh pressure pistons. More particularly, the present invention relates to a piston seal assembly and method for an ultra-high pressure liquid driven compressor.

Background

In the research of the ultrahigh pressure liquid-driven compressor, the cylinder piston sealing technology can play a key role in the performance of the compressor, and is the key point and the difficulty of the technical research of the liquid-driven compressor, but because the application time is short, the research contents disclosed on the sealing structure, the method and the sealing material under ultrahigh pressure are less at present. Especially, under the condition of 105MPa ultrahigh pressure working condition, the gas pressure is directly loaded on the contact surface of the sealing element and the cylinder barrel, so that larger friction force is generated, eccentric wear is easy to occur, the sealing effect of the sealing element is difficult to guarantee, and meanwhile, the service life of the sealing element is seriously shortened.

In order to solve the problems, a piston sealing assembly and a method of an ultrahigh pressure liquid-driven compressor are needed to be designed, and the effectiveness and durability of the piston sealing of the compressor are improved.

Disclosure of Invention

The invention aims to provide a piston sealing assembly and a method of an ultrahigh-pressure hydraulic drive compressor, which adopt multiple sealing assemblies to disperse the pressure bearing of a single sealing element and are matched with curved surface designs and connecting structures among different sealing elements and supporting elements to realize the improvement of the sealing effect and the durability of a compressor piston.

To achieve these objects and other advantages in accordance with the purpose of the invention, there is provided a piston seal assembly of an ultra high pressure liquid driven compressor, comprising:

the sealing assembly is of an annular structure and is sleeved on the piston through a preset annular groove, the sealing assembly comprises a plurality of supporting pieces and a plurality of sealing pieces, the supporting pieces and the sealing pieces are alternately sleeved in the annular groove along the axial direction to form a multi-sealing structure, the contact surfaces of the adjacent supporting pieces and the sealing pieces are attached and arranged and are backwards recessed along the gas pressure direction, and two ends of the sealing assembly are respectively provided with the supporting pieces which are respectively abutted against two ends of the annular groove;

the inner ring surface and the outer ring surface of the sealing element are conical surfaces and are coaxially arranged, the outer ring surface of the sealing element at the front end surface is in interference fit with the cylinder barrel, and the outer ring surface of the sealing element at the rear end surface is in clearance fit with the cylinder barrel; the inner ring surface and the outer ring surface of the supporting piece are cylindrical surfaces and are coaxially arranged, the outer ring surface of the supporting piece at any end face is in clearance fit with the cylinder barrel, and the distance between the inner ring and the outer ring is larger than that between the inner ring and the outer ring at the rear end face of the sealing piece.

Preferably, in the piston sealing assembly of the ultrahigh-pressure liquid-driven compressor, the contact surfaces of the sealing element and the supporting element are curved surfaces which are arranged at the front ends of the intrados facing to the gas pressure direction, and the axial cross sections of the curved surfaces are symmetrical along the central axes of the inner annular surface and the outer annular surface of the sealing element;

the two sides of the front end face of the sealing element are respectively recessed backwards along the gas pressure direction to form first conical surfaces, the rear ends of the two first conical surfaces are continuously recessed backwards along the gas pressure direction and connected at the central axis to form first cambered surfaces, and the two sides of the rear end face of the sealing element are respectively recessed backwards along the gas pressure direction and connected at the central axis to form second cambered surfaces; the front end face of the supporting piece is matched with and jointed with the rear end face of the sealing piece in shape, and the rear end face of the supporting piece is matched with and jointed with the front end face of the sealing piece in shape.

Preferably, the piston sealing assembly of the ultrahigh pressure liquid drive compressor further comprises two pressure ring pieces which are respectively arranged at two ends of the sealing assembly, any pressure ring piece is clamped between the sealing assembly and the annular groove, one end of each pressure ring piece is matched and connected with the end part of the adjacent annular groove, and the other end of each pressure ring piece is matched and attached with the end surface of the adjacent supporting piece.

Preferably, in the piston sealing assembly of the ultrahigh-pressure liquid-driven compressor, a contact surface between a pressure ring piece close to one end of the cylinder and an adjacent support piece is a second tapered surface with a wide front part and a narrow back part, and an annular mounting groove is formed in the contact surface between the second tapered surface and the piston; the piston sealing assembly of the ultrahigh pressure liquid drive compressor further comprises a sealing ring, and the sealing ring is clamped between the piston and the pressure ring piece and between the supporting pieces through the annular mounting groove.

Preferably, the piston sealing assembly of the ultrahigh-pressure liquid-driven compressor further comprises a pre-tightening device, the pre-tightening device is arranged between the pressure ring piece close to one end of the cylinder and the end part of the adjacent annular groove, the pre-tightening device comprises two supports, the supports are sleeved on the annular groove at intervals, the supports positioned at the front end are abutted against the end part of the adjacent annular groove, and the supports positioned at the rear end are abutted against the front end face of the adjacent pressure ring piece; and the elastic element is arranged between the two supports along the length direction of the piston and is fixedly connected with the two supports.

Preferably, in the piston seal assembly of the ultrahigh-pressure liquid-driven compressor, the annular groove includes a stepped groove and a flat groove, the stepped groove is continuously arranged on the piston along the gas pressure direction, the flat groove is located at the rear end of the gas pressure direction, the depths of positions in the groove are equal, the stepped groove extends forwards from the front end surface of the flat groove in the opposite direction and is recessed towards the axial direction of the piston to form a multi-stage stepped structure, and the front end part of the stepped groove is communicated with the inside of the cylinder;

piston seal assembly of superhigh pressure liquid drive compressor still includes the jump ring, seal assembly card is established flat inslot and rather than the tip butt of keeping away from the cylinder, jump ring cooperation card is established step inslot and with adjacent seal assembly's tip butt.

The invention also provides a piston sealing method of the ultrahigh pressure liquid-driven compressor, which comprises the following steps:

s1, coaxially arranging an annular groove at the end part of a piston close to a cylinder;

s2, sleeving a sealing ring in a flat groove of the annular groove according to a set position;

s3, according to a set sequence, respectively sleeving a plurality of supporting pieces, a plurality of sealing pieces and two pressure ring pieces into the rear part of the flat groove along the axial direction, enabling the pressure ring piece far away from the air cylinder to be abutted against the rear end part of the flat groove, and enabling the pressure ring piece close to one end of the air cylinder to be matched and clamped with an annular mounting groove between the supporting pieces on the sealing ring;

s4, mounting a pre-tightening device at the front part of the flat groove, and enabling a support at the rear end to be abutted against an adjacent pressure ring piece;

and S5, clamping the clamp spring into the step groove of the annular groove, and enabling the rear end face of the clamp spring to abut against and press the support at the front end.

The invention at least comprises the following beneficial effects:

1. the invention disperses the single-channel sealing bearing by arranging the multiple sealing structures, reduces the pressure born by the single-stage sealing element in the working process of the compressor, greatly reduces the abrasion speed of the sealing, increases the reliability and the sealing effect of the sealing structure, and realizes the improvement of the sealing effect and the durability of the compressor piston by matching with the curved surface design and the connecting structure among different sealing elements and supporting pieces;

2. the invention aims at the sealing assembly to be matched with a front-back guiding and supporting structure, so that the main seal of the piston is stably positioned, the coaxiality of the sealing assembly in the cylinder body of the compressor along with the linear motion of the piston is ensured, the problems of eccentric wear and the like caused by uneven abrasion of a sealing element are avoided, the service life of the seal is prolonged, the effectiveness and the durability of the sealing assembly of the compressor are further improved, meanwhile, the adaptability of the sealing assembly in the environment of oil-free lubrication sealing ring is improved, the sealing assembly can be suitable for a wider range of compressor types and operation conditions, and the sealing assembly has a good application prospect in the field of liquid-driven compressors.

Additional advantages, objects, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention.

Drawings

Fig. 1 is a schematic axial cross-sectional view of a piston seal assembly of an ultrahigh-pressure liquid-driven compressor according to an embodiment of the present invention;

FIG. 2 is an axial cross-sectional structural view of the seal in the above embodiment;

fig. 3 is a schematic axial sectional structure of the support member in the above embodiment.

Description of reference numerals:

1. a seal member; 2. a support member; 3. pressing the ring piece; 41. a support; 42. an elastic element; 43. a clamp spring; 44. a screw; 5. a seal ring; 6. a piston axis; 71. a first conical surface; 72. a first arc surface; 73. a second arc surface; 74. a second tapered surface; 81. a conical surface; 82. a cylindrical surface.

Detailed Description

The present invention is further described in detail below with reference to the attached drawings so that those skilled in the art can implement the invention by referring to the description text.

It is to be noted that the experimental methods described in the following embodiments are all conventional methods unless otherwise specified, and the reagents and materials, if not otherwise specified, are commercially available; in the description of the present invention, the terms "lateral", "longitudinal", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, are only for convenience in describing the present invention and simplifying the description, and do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present invention.

As shown in fig. 1 to 3, the present invention provides a piston seal assembly of an ultra-high pressure liquid driven compressor, comprising:

the sealing assembly is of an annular structure and is sleeved on the piston through a preset annular groove, the sealing assembly comprises a plurality of supporting pieces 2 and a plurality of sealing pieces 1, the supporting pieces 2 and the sealing pieces 1 are alternately sleeved in the annular groove along the axial direction to form a multi-sealing structure, the contact surfaces of the adjacent supporting pieces 2 and the sealing pieces 1 are attached to each other and are recessed backwards along the gas pressure direction, and the two ends of the sealing assembly are respectively provided with the supporting pieces which are respectively abutted against the two ends of the annular groove;

the inner ring surface and the outer ring surface of the sealing element are both conical surfaces 81 and are coaxially arranged, the outer ring surface of the sealing element at the front end surface is in interference fit with the cylinder barrel, and the outer ring surface of the sealing element at the rear end surface is in clearance fit with the cylinder barrel; the inner ring surface and the outer ring surface of the supporting piece are cylindrical surfaces 82 and are coaxially arranged, the outer ring surface of the supporting piece at any end surface is in clearance fit with the cylinder barrel, and the distance between the inner ring and the outer ring is larger than that between the inner ring and the outer ring at the rear end surface of the sealing piece.

In the technical scheme, the sealing assembly is integrally sleeved on the piston and is positioned between the piston and the compressor cylinder, when the piston linearly moves along the inner wall of the cylinder, the sealing assembly synchronously moves along with the piston, and because the sealing assembly is clamped on the piston through the annular groove, relative sliding does not exist between the integral sealing assembly and the piston, and the reliability and effectiveness of sealing are ensured. The installation direction of the piston sealing assembly of the ultrahigh pressure liquid driven compressor is set as follows: the front (left direction in figure 1) faces the compressor end cover, the rear (right direction in figure 1) faces the piston rod, and the gas is pressed from the front to the rear of the sealing assembly (piston) along the axial direction in the gas compression process, namely the gas pressure direction is from the front to the rear along the piston axis 6. The number of the supporting pieces and the number of the sealing pieces can be multiple, the sealing pieces are arranged between any two adjacent supporting pieces, the sealing pieces are used as main seals to seal the gaps between the piston and the cylinder barrel and also seal the gaps between the two adjacent supporting pieces to connect the two adjacent supporting pieces into a whole, and the specific number of the supporting pieces and the specific number of the sealing pieces can be selected and adjusted according to different working conditions of the compressor; no matter what specific quantity chooseed for use, because need the stable support at the both ends of whole sealing members, support piece's total amount needs more one than the sealing member, has avoided the contact of sealing member with annular groove tip, has also guaranteed that the sealing member is difficult for receiving the damage when forming stable support structure, improves seal assembly job stabilization nature. In the present embodiment, the number of the supporting members is set to three, and accordingly, the number of the sealing members to be disposed between the adjacent two supporting members is two. The sealing element and the supporting element are both of annular structures, the inner annular surface of the sealing element and the supporting element are clamped with the annular groove on the outer side wall of the piston, and the outer annular surface of the sealing element and the supporting element are both connected with the inner wall of the cylinder barrel in a matched mode. The sealing elements play a role of main sealing, and the supporting elements are arranged at two ends of each sealing element, so that supporting, guiding and limiting effects are provided for the middle sealing element, and an auxiliary sealing effect is achieved; the sealing elements and the supporting elements are distributed on the annular groove on the outer side of the piston in a staggered mode along the direction of the axis 6 of the piston to form a multiple sealing structure, the adjacent sealing elements and the supporting elements are connected in a fit mode to form an annular contact surface, and the axial section of the contact surface at any position in the circumferential direction (annular direction) is a curved surface which is recessed backwards (namely recessed from front to back) along the gas pressure direction.

Specifically, as shown in fig. 2, the inner annular surface and the outer annular surface of the sealing element are coaxial conical surfaces arranged at intervals, the arrangement directions (in the gas pressure direction) of the vertexes corresponding to the two conical surfaces are opposite, the axial section of the sealing element is cut, the conical surface corresponding to the outer annular surface of the sealing element is inclined in the direction close to the piston axis 6 along the gas pressure direction, the conical surface corresponding to the inner annular surface is inclined in the direction far from the piston axis 6 along the gas pressure direction, and the two conical surfaces are symmetrically arranged relative to the center line (up and down) of the inner annular surface and the center line (up and down) of the outer annular surface, so that the pressure bearing from the middle part of the stressed surface to the two sides is facilitated. For the sealing member, the section of the sealing member forms a sealing structure with wide front and narrow back, namely the thickness (height direction in the figure) at the front end face is larger than that at the back end face; meanwhile, the inner ring surface and the outer ring surface of the supporting piece are both arranged to be of a conventional cylindrical surface structure so as to be better attached to the piston and the side wall of the cylinder barrel, and the thickness of the supporting piece (namely the distance between the inner ring and the outer ring of the supporting piece) is set to be smaller than the thickness of the sealing piece at the front end face and larger than the thickness of the sealing piece at the rear end face. Because the supporting piece is in clearance fit connection with the cylinder barrel, the outer ring surface at the front end face of the sealing piece is in interference fit connection with the cylinder barrel, a more reasonable sealing supporting structure is formed between the sealing piece and the supporting piece by the structure limiting scheme of the sealing assembly, the gas pressure from the cylinder direction acts on the end face of the main seal and presses the main seal towards the backward supporting piece, and in the pressing process, because a clearance exists between the rear end face of the sealing piece and the cylinder barrel, the sealing piece can adapt to the deformation of the sealing piece in a certain range in the pressing process, and the supporting piece forms a full-coverage type support for the rear end face of the sealing piece in the rear direction, and because the thickness of the supporting piece is greater than that of the sealing piece in the rear end face, the support can adapt to the deformation of the sealing piece in the pressing process on one hand, and on the other hand, the pressure is effectively buffered through the curved surface connecting structure recessed in the middle between the supporting piece and the sealing piece; the pressure which is not buffered/unloaded is loaded backwards to another group of sealing parts-supporting parts for secondary buffering/unloading, the structural cooperation of the multiple sealing can better assist in bearing pressure, and the whole sealing assembly is conducted through interaction force to apply gas pressure to the main seal (sealing part), so that the acting force between the sealing part and the cylinder wall is higher than the gas pressure, and therefore the adaptability of the sealing assembly in a high-pressure environment is greatly improved, and the sealing reliability is guaranteed. In addition, the curved surface connection structure of support piece and sealing member has improved the stability of being connected between sealing member and the support piece under the condition that does not change or increase seal assembly overall structure, carry out relative spacing to sealing member and support piece from a plurality of directions through the curved surface structure sunken along the gas pressure direction, make the piston main seal have stable location, the axiality when having guaranteed seal assembly in the compressor cylinder body and being linear motion along with the piston, thereby avoid the uneven partial wear scheduling problem that causes of wearing and tearing of sealing member, the life who seals has prolonged, thereby improve compressor seal assembly's validity and durability, the adaptability of seal assembly work under oil-free lubricated sealing ring border has been improved simultaneously, make it can be applicable to the compressor type of wider range and different operating condition, have good application prospect in liquid drive compressor field.

In another technical solution, in the piston sealing assembly of the ultra-high pressure liquid driven compressor, the contact surfaces of the sealing element and the supporting element are both curved surfaces with the inner arc surfaces facing the front end of the gas pressure direction, and the axial cross sections of the curved surfaces are symmetrical along the central axes of the inner annular surface and the outer annular surface of the sealing element;

the two sides of the front end surface of the sealing element are respectively recessed backwards along the gas pressure direction to form a first conical surface 71, the rear ends of the two first conical surfaces continue to be recessed backwards along the gas pressure direction and are connected at the central axis to form a first cambered surface 72, and the two sides of the rear end surface of the sealing element are respectively recessed backwards along the gas pressure direction and are connected at the central axis to form a second cambered surface 73; the front end face of the supporting piece is matched with and jointed with the rear end face of the sealing piece in shape, and the rear end face of the supporting piece is matched with and jointed with the front end face of the sealing piece in shape.

In the above technical solution, the central axis of the inner annular surface and the outer annular surface of the sealing element is the central line between the inner annular surface and the outer annular surface on the axial cross section of the sealing element in fig. 2, the front end surface of the sealing element is a curved surface formed by the first conical surface and the first curved surface, and is symmetrical (up and down) with respect to the central axis, and the rear end surface of the sealing element is a curved surface formed by the second curved surface and is also symmetrical with respect to the central axis, so that the stress structure of the sealing element is further optimized by matching with the tapered cross section with a wide front part and a narrow rear part formed between the inner annular surface and the outer annular surface of the sealing element. According to stress structure analysis and test data, when two first conical surfaces of the sealing element are arranged at 90 degrees, the curvature radius of the first cambered surface is 2-5mm, and the curvature radius of the second cambered surface is 4-7mm, a better sealing effect and durability can be obtained. In this embodiment, the distance between the inner ring and the outer ring of the sealing element at the front end face is 20.2mm, the distance between the inner ring and the outer ring of the sealing element at the rear end face is 19.8mm, the distance between the inner ring and the outer ring of the supporting element is 20mm, the two first conical surfaces are arranged at 90 degrees, the curvature radius of the first cambered surface is 3.5mm, and the curvature radius of the second cambered surface is 5.2mm; as shown in figure 3, the shapes of the front end face and the rear end face of the supporting piece are determined according to the shapes of the end faces of the sealing pieces matched and supported by the supporting piece, the supporting piece is arranged between the two sealing pieces, the shape of the front end face of the supporting piece is matched with the shape of the rear end face of the front sealing piece and is in fit connection with the shape of the rear end face of the rear sealing piece, and the shape of the rear end face of the supporting piece is matched with the shape of the front end face of the rear sealing piece and is in fit connection with the front end face of the rear sealing piece, so that better supporting, guiding, limiting and buffering effects are achieved.

And (3) testing the performance of the sealing assembly: the sealing assembly in the embodiment and another sealing assembly assembled by a conventional structure (the contact surfaces of each sealing element and a supporting element are flat, but the number and the thickness of the contact surfaces are the same as those of the embodiment) are arranged on the annular groove on the outer side of the piston with the same specification, and sealing durability tests are respectively carried out on the two pistons to verify the sealing performance of the pistons.

Specifically, a piston is installed in a pressure cylinder, the hydraulically driven piston reciprocates in a cylinder body, and then helium is used for cyclic pressurization-depressurization testing: maintaining the pressure of gas at the outlet of the pressurizing cylinder at 105MPa and the pressure of gas at the inlet of the pressurizing cylinder at 45MPa, performing pressurizing and depressurizing circular flow of the pressurizing gas in a pipeline, detecting the sealing leakage condition through a gas flowmeter behind the piston, and judging the service life of the sealing assembly, wherein the leakage display value exceeds 0.17L/min. The service life of the seal assembly assembled using the conventional structure was measured to be about 800 hours, whereas the service life of the seal assembly of the present embodiment was 6000 hours. Therefore, in an ultrahigh pressure working environment, the sealing assembly disclosed by the invention is used for sealing a compressor piston, the sealing effect is ensured, the service life of the seal is greatly prolonged, and the problems of sealing failure and frequent replacement of the sealing assembly are avoided.

In another technical scheme, the piston sealing assembly of the ultrahigh pressure liquid drive compressor further comprises two pressure ring pieces 3 which are respectively arranged at two ends of the sealing assembly, any pressure ring piece is clamped between the sealing assembly and the annular groove, one end of each pressure ring piece is matched and connected with the end part of the adjacent annular groove, and the other end of each pressure ring piece is matched and attached with the end surface of the adjacent supporting piece. Wherein, because the support piece that is located seal assembly both ends need respectively with annular groove both ends butt, but according to support piece's structural design, its front and back terminal surface shape need with the terminal surface shape cooperation of sealing member, consequently, have unable adaptability laminating scheduling problem when support piece is direct with annular groove tip butt, cause support piece location unstability or damage easily. In order to ensure the stability of the matching connection of the supporting piece and the annular groove, the two ends of the sealing assembly are respectively provided with a pressing ring piece so as to adapt to the end surface shape of the supporting piece positioned at the end part, and the other end of the pressing ring piece can be attached to the end surface of the groove to ensure the stability of the whole sealing assembly fixed in the annular groove. Any pressure ring piece is arranged to be of an annular structure and can be sleeved on an annular groove of the piston together with the sealing assembly, and in order to ensure that gas pressure can act on the main seal smoothly and the reciprocating motion of the piston in the cylinder barrel is not influenced, the outer annular surface of the pressure ring piece is in clearance connection with the inner wall of the cylinder barrel. Meanwhile, the ring pressing piece also plays a role in acting force transmission and support, the supporting piece and the sealing piece can be pressed inwards from two ends through the limitation of the installation position (on the piston), certain pretightening force is provided for the main sealing structure and the auxiliary sealing structure, the sealing assembly is connected into a whole better, and the integrity and the sealing stability of the sealing assembly are further ensured.

In another technical scheme, in the piston sealing assembly of the ultrahigh pressure liquid drive compressor, the contact surface between the pressure ring piece close to one end of the cylinder and the adjacent support piece is a second tapered surface 74 with a wide front part and a narrow back part, and an annular mounting groove is formed in the contact surface between the second tapered surface and the piston; the piston sealing assembly of the ultrahigh pressure liquid drive compressor further comprises a sealing ring 5, and the sealing ring is clamped between the piston and the pressure ring piece and between the supporting pieces through the annular mounting groove. The sealing ring is arranged between the sealing component and the piston (annular groove) to seal the connecting surface of the inner side of the sealing component, so as to further prevent the cavities on the two sides of the piston from generating fluid exchange. In order to ensure that the sealing effect is not influenced by the internal pressure conduction structure of the sealing assembly, a conical surface is arranged between the pressure ring piece positioned at the front end (close to one end of the air cylinder) and the support piece for connection, an annular mounting groove is formed in the joint of the conical surface and the piston, the sealing ring can be clamped in the annular mounting groove during positioning and mounting, the positioning and mounting between the sealing ring and the sealing assembly are facilitated, and the sealing ring after mounting is in interference fit with the annular mounting groove and the piston so as to ensure the sealing effect.

In another technical scheme, the piston sealing assembly of the ultrahigh pressure liquid drive compressor further comprises a pre-tightening device, the pre-tightening device is arranged between the pressure ring piece close to one end of the cylinder and the end part of the adjacent annular groove, the pre-tightening device comprises two support seats 41, the two support seats are arranged on the annular groove in a spaced and sleeved mode, the support seat positioned at the front end is abutted against the end part of the adjacent annular groove, and the support seat positioned at the rear end is abutted against the front end face of the adjacent pressure ring piece; an elastic element 42, which is arranged between the two seats along the length of the piston and is fixedly connected thereto. The piston is provided with a piston, a horizontal part and a vertical part, wherein the two supports are of an annular sleeve structure fixed on the piston, the axial section of the support is L-shaped, the two supports are symmetrically arranged on the piston, the horizontal part of any support is attached to the outer side wall of the piston, and the vertical parts of the two supports are connected through an elastic element. The elastic element can be a spring, the whole of the elastic element is sleeved on the annular groove of the piston, the arrangement distance of the two supports is smaller than the free length of the spring, and the installed elastic element is in a compressed state. The pre-tightening device is arranged at the front end of the whole sealing assembly, pre-tightening pressure from inside to outside exists in the pre-tightening device in the initial state, extra initial pre-tightening force can be provided for the sealing assembly after the sealing assembly is assembled with the sealing assembly at the rear, and meanwhile the multi-layer sealing is compressed from the inside and the outside by matching with the pressing ring piece structure, so that the sealing effect of the main sealing is further improved.

In another technical scheme, the annular groove comprises a stepped groove and a flat groove, the stepped groove and the flat groove are continuously arranged on the piston along the gas pressure direction, the flat groove is positioned at the rear end of the gas pressure direction, the depths of all positions in the flat groove are equal, the stepped groove extends forwards from the front end surface of the flat groove in the opposite direction and is recessed towards the axial direction of the piston to form a multi-stage step structure, and the front end part of the stepped groove is communicated with the inside of the cylinder;

piston seal assembly of superhigh pressure liquid drive compressor still includes jump ring 43, the seal assembly card is established flat inslot and rather than keeping away from the tip butt of cylinder, jump ring cooperation card is established step inslot and with adjacent seal assembly's tip butt.

In the technical scheme, the annular groove is set into grooves with two different shapes, namely a front groove and a rear groove, which are communicated with the front end cylinder, on one hand, a shielding structure at the front end of the flat groove is removed, namely, only one end part with a limiting function on the rear end surface of the flat groove is arranged, the front end surface is communicated with the stepped groove which is further sunk, the sealing assembly is conveniently sleeved from the end part at the same side of the piston, in addition, after the sealing assembly is sleeved, the stepped groove is clamped by using a clamp spring, so that the limiting of the sealing assembly can be realized, the clamp spring 43 is formed by splicing two semicircular structures, and after the splicing is finished, the semicircular rings are locked by using an upper screw 44 and a lower screw 44, so that the installation and the limiting of the integral sealing assembly on the piston can be completed; on the other hand, the mounting structure enables all annular structures (including the sealing element, the supporting element, the ring pressing piece, the support seat and the like) in the sealing assembly to be made of rigid materials, the problem that the sealing assembly is difficult to mount with the annular groove due to the fact that the sealing assembly does not have elastic deformation is solved, or a single annular structure needs to be arranged into a split type connecting structure for mounting, and the sealing stability and the durability of the sealing assembly are further guaranteed from the material and the mounting structure. In this embodiment, the processing material of the pressure ring member and the supporting member may be a metal material such as 316L, or a polymer engineering plastic such as PEEK, and the processing material of the sealing member may be a self-lubricating modified material PTFE.

The invention also provides a piston sealing method of the ultrahigh pressure liquid-driven compressor, which comprises the following steps:

the method comprises the following steps that S1, an annular groove is coaxially formed in the end portion, close to a cylinder, of a piston, the annular groove comprises a flat groove located in the rear portion and a step groove located in the front portion, and the front end of the step groove is communicated with the interior of the cylinder at the front end of the piston;

s2, sleeving a sealing ring 5 in a flat groove of the annular groove according to a set position, wherein the installation position of the sealing ring 5 is the connection position of an annular installation groove and the flat groove on the contact surface of a support piece 2 close to one end of the cylinder and an adjacent pressure ring piece 3 after the sealing assembly is installed;

s3, according to a set sequence, a plurality of supporting pieces 2, a plurality of sealing pieces 1 and two pressure ring pieces 3 are respectively sleeved into the rear part of the flat groove along the axial direction, so that the pressure ring piece far away from the cylinder is abutted against the rear end part of the flat groove, and the pressure ring piece close to one end of the cylinder is clamped on the sealing ring 5 in a matched manner with an annular mounting groove between the supporting pieces;

in the embodiment, the mounting sequence of the plurality of supporting pieces, the plurality of sealing pieces and the two pressing ring pieces is pressing ring piece-supporting piece-sealing piece-supporting piece-pressing ring piece, and the mounting direction is that the pressing ring piece-supporting piece-sealing piece-pressing ring piece is mounted from the rear end part to the front end part of the flat groove along the axial direction;

s4, mounting a pre-tightening device at the front part of the flat groove to enable the support 41 at the rear end to be abutted against the adjacent pressure ring piece 3, wherein the support 41 at the front end is just arranged at the front end part of the flat groove;

s5, clamping the clamp spring 43 into the step groove of the annular groove, and enabling the rear end face of the clamp spring 43 to be abutted against and pressed against the support 41 at the front end; specifically, two semicircular structures with the jump ring are blocked respectively in the both sides in step groove and are docked, reuse two bolts and lock two semicircular structure tops and the predetermined mounting hole in bottom respectively, accomplish the fixed joint in jump ring and step groove promptly, under the limit of the step structure in step groove, relative displacement can't take place for the jump ring, and simultaneously, the jump ring is close to the terminal surface in flat groove and the support butt that lies in the front end among the preloading device, realized to seal assembly in the flat groove, clamping ring spare and preloading device's whole spacing and compress tightly. The outer side walls of the pre-tightening device and the clamp spring are in clearance with the inner side wall of the cylinder barrel, so that normal work of the piston and the sealing effect of the sealing assembly are not affected.

While embodiments of the invention have been described above, it is not limited to the applications set forth in the description and the embodiments, which are fully applicable in various fields of endeavor to which the invention pertains, and further modifications may readily be made by those skilled in the art, it being understood that the invention is not limited to the details shown and described herein without departing from the general concept defined by the appended claims and their equivalents.

Claims (7)

1. A piston seal assembly of a super high pressure liquid driven compressor comprising:

the sealing assembly is of an annular structure and is sleeved on the piston through a preset annular groove, the sealing assembly comprises a plurality of supporting pieces and a plurality of sealing pieces, the supporting pieces and the sealing pieces are alternately sleeved in the annular groove along the axial direction to form a multi-sealing structure, the contact surfaces of the adjacent supporting pieces and the sealing pieces are attached and arranged and are backwards recessed along the gas pressure direction, and two ends of the sealing assembly are respectively provided with the supporting pieces which are respectively abutted against two ends of the annular groove;

the inner ring surface and the outer ring surface of the sealing element are conical surfaces and are coaxially arranged, the outer ring surface of the sealing element at the front end surface is in interference fit with the cylinder barrel, and the outer ring surface of the sealing element at the rear end surface is in clearance fit with the cylinder barrel; the inner ring surface and the outer ring surface of the supporting piece are cylindrical surfaces and are coaxially arranged, the outer ring surface of the supporting piece at any end face is in clearance fit with the cylinder barrel, and the distance between the inner ring and the outer ring is larger than that between the inner ring and the outer ring of the sealing piece at the rear end face.

2. The piston seal assembly of an ultrahigh-pressure liquid-driven compressor according to claim 1, wherein the contact surfaces of the sealing member and the support member are curved surfaces with the inner curved surfaces facing the front end in the gas pressure direction, and the axial cross sections of the curved surfaces are symmetrical along the central axes of the inner annular surface and the outer annular surface of the sealing member;

the two sides of the front end face of the sealing element are respectively recessed backwards along the gas pressure direction to form first conical surfaces, the rear ends of the two first conical surfaces continue to be recessed backwards along the gas pressure direction and are connected at the central axis to form a first cambered surface, and the two sides of the rear end face of the sealing element are respectively recessed backwards along the gas pressure direction and are connected at the central axis to form a second cambered surface; the front end face of the supporting piece is matched with and jointed with the rear end face of the sealing piece in shape, and the rear end face of the supporting piece is matched with and jointed with the front end face of the sealing piece in shape.

3. The piston seal assembly of an ultrahigh-pressure liquid-driven compressor according to claim 2, further comprising two pressure ring members which are respectively disposed at both ends of the seal assembly, wherein any one of the pressure ring members is clamped between the seal assembly and the annular groove, one end of the pressure ring member is connected to the end of the adjacent annular groove in a fitting manner, and the other end of the pressure ring member is connected to the end face of the adjacent support member in a fitting manner.

4. The piston seal assembly of the ultrahigh pressure liquid driven compressor according to claim 3, wherein the contact surface between the pressure ring member close to one end of the cylinder and the adjacent support member is a second tapered surface with a wide front part and a narrow back part, and an annular mounting groove is formed in the contact surface between the second tapered surface and the piston; the piston sealing assembly of the ultrahigh pressure liquid drive compressor further comprises a sealing ring, and the sealing ring is clamped between the piston and the pressure ring piece and between the supporting pieces through the annular mounting groove.

5. The piston seal assembly of the ultra-high pressure liquid driven compressor according to claim 3, further comprising a pre-tightening device arranged between the pressure ring member near one end of the cylinder and the end of the adjacent annular groove, wherein the pre-tightening device comprises two supports which are arranged on the annular groove in a spaced manner, 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 member; and the elastic element is arranged between the two supports along the length direction of the piston and is fixedly connected with the two supports.

6. The piston seal assembly of an ultrahigh-pressure liquid driven compressor according to claim 1, wherein the annular groove comprises a stepped groove and a flat groove which are continuously provided on the piston in the gas pressure direction, the flat groove is provided at the rear end in the gas pressure direction and has the same depth at each position in the groove, the stepped groove extends forward from the front end surface of the flat groove in the opposite direction and is recessed in the axial direction of the piston to form a multistage stepped structure, and the front end portion of the stepped groove communicates with the inside of the cylinder;

piston seal assembly of superhigh pressure liquid drive compressor still includes the jump ring, seal assembly card is established the flat inslot and rather than keeping away from the tip butt of cylinder, jump ring cooperation card is established the step inslot and with adjacent seal assembly's tip butt.

7. A piston sealing method of a superhigh pressure liquid-driven compressor is characterized by comprising the following steps:

s1, coaxially arranging an annular groove at the end part of a piston close to a cylinder;

s2, sleeving a sealing ring in a flat groove of the annular groove according to a set position;

s3, according to a set sequence, respectively sleeving a plurality of supporting pieces, a plurality of sealing pieces and two pressure ring pieces into the rear part of the flat slot along the axial direction, enabling the pressure ring piece far away from the air cylinder to be abutted against the rear end part of the flat slot, and enabling the pressure ring piece close to one end of the air cylinder to be in matched clamping connection with an annular mounting groove between the supporting pieces on the sealing ring;

s4, mounting a pre-tightening device at the front part of the flat groove, and enabling a support at the rear end to be abutted against an adjacent pressure ring piece;

s5, clamping the clamp spring into the step groove of the annular groove, and enabling the rear end face of the clamp spring to be abutted and pressed against the support at the front end.

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