Piston ring assembly, piston compressor and method of sealing a compression chamber

Abstract

The piston ring assembly (1) includes first and second continuous sealing rings (2, 4) and an elastic ring seat (3). The first and second sealing rings (2, 4) extend in a circumferential direction (U) and each has an outer peripheral surface (2a, 4a). The first sealing ring (2) has a first center point (M1) relative to its outer peripheral surface (2a), and the second sealing ring (4) has a second center point (M1) relative to its outer peripheral surface (4a). The first and second sealing rings (2, 4) each have a longitudinal axis (L) extending perpendicular to the circumferential direction (U). The ring seat (3) extends in the circumferential direction (U), and the ring seat (3) and the first and second sealing rings (2, 4) are designed to be mutually adapted such that the first and second sealing rings (2, 4) are arranged successively in the direction of the longitudinal axis (L) into the ring seat (3), and their first and second center points (M1, M2) are arranged radially spaced apart from each other relative to the longitudinal axis (L). When the piston ring assembly (1) is used according to the invention, these sealing rings (2, 4) press against the inner wall (11a) of the cylinder body (11) in opposite directions.

Description

Technical Field

[0001] This invention relates to a piston ring assembly. It also relates to a piston compressor including the piston ring assembly. Furthermore, it relates to a method for sealing a compression chamber. Background Technology

[0002] A reciprocating compressor is known to include a cylinder and a piston that can move linearly therein. In one possible embodiment, piston rings are arranged to the piston, sliding along the cylinder wall, thus sealing the compression chamber defined by the cylinder and the movable piston. Published document WO98 / 55783A1... Figure 6 A dry-running reciprocating compressor is disclosed, which has piston rings arranged to the piston and scraping against the cylinder wall. Such known piston rings are only conditionally suitable for high pressure differentials because they exhibit significant cold flow under load, leading to rapid wear of the piston rings. US 2013 / 0154197 A1 discloses a sealing arrangement for the piston rod of a reciprocating compressor, comprising two consecutive sealing rings movably mounted within a common ring seat transverse to the piston rod's running direction for wear compensation. However, this sealing arrangement does not contribute to sealing the compression chamber defined by the cylinder and the movable piston. Summary of the Invention

[0003] The objective of this invention is to provide a piston ring assembly and a piston compressor with more advantageous operating characteristics.

[0004] This task is solved using a piston ring assembly with features intended to be protected by the present invention. Further protection is intended for a further advantageous embodiment of the invention. The task is also solved using a piston compressor including features intended to be further protected by the present invention. Further protection is also intended for an advantageous embodiment. The task is also solved using a method for sealing a compression chamber including features intended to be further protected by the present invention. Further protection is intended for a further advantageous method. The task is also solved using a piston ring assembly intended to be further protected by the present invention as a pressure barrier for sealing dynamic pressure components.

[0005] This task is specifically addressed using a piston ring assembly comprising a first and second continuous sealing ring and an elastic ring seat, wherein the first and second sealing rings extend in a circumferential direction and each has an outer circumferential surface, wherein the first sealing ring has a first center point relative to its outer circumferential surface, and the second sealing ring has a second center point relative to its outer circumferential surface, wherein each of the first and second sealing rings has a longitudinal axis extending perpendicular to the circumferential direction, wherein the ring seat extends in a circumferential direction, and wherein the ring seat and the first and second sealing rings are designed to be mutually adapted such that the first and second sealing rings are arranged sequentially in the longitudinal axis direction within the ring seat, and their first and second center points are arranged radially spaced apart from each other relative to the longitudinal axis.

[0006] The task is also solved using a reciprocating compressor, which includes a cylinder, a piston disposed within the cylinder, and at least one piston ring assembly disposed to the piston according to the invention.

[0007] A reciprocating compressor includes a cylinder and a piston that define a compression chamber. The piston advantageously has a first partial section and a subsequent second partial section along the longitudinal axis, starting from the compression chamber. At least one piston ring assembly is arranged along the first partial section, and at least one piston ring is preferably arranged along the second partial section to seal the static pressure. The piston ring assembly preferably seals the dynamic pressure portion.

[0008] The task also utilizes a method for sealing a compression chamber defined by a cylinder and a piston disposed therein and movable in the longitudinal direction, wherein a piston ring assembly including first and second consecutive sealing rings is disposed to the piston, wherein the first and second consecutive sealing rings are laterally pressed in a stationary state, particularly against the inner wall of the cylinder in opposite directions perpendicular to the longitudinal axis, and wherein the first and second consecutive sealing rings are additionally pressed against the inner wall of the cylinder in opposite directions by the increased internal pressure within the compression chamber of the cylinder during the piston compression phase.

[0009] In an advantageous embodiment, the piston ring assembly according to the invention is not completely sealed in the longitudinal direction, but only partially sealed. Such a piston ring assembly is particularly suitable as a pressure barrier for sealing dynamic pressure sections.

[0010] The piston ring assembly according to the invention has the advantage of being designed to be extremely stable and suitable for applying high pressure differentials, for example, pressures up to 500 bar, and is particularly suitable for compressing hydrogen. One reason for the extreme stability of the piston ring assembly according to the invention is that the sealing ring is a continuous one-piece design, preferably made of wear-resistant materials, particularly metals such as copper, gray cast iron, or sintered iron, or plastics such as polytetrafluoroethylene (PTFE), filled polytetrafluoroethylene (PTFE), or high-temperature polymers such as polyetheretherketone (PEEK), polyimide (PI), or epoxy resin. The piston ring assembly according to the invention comprises two sealing rings that press against the inner wall of the cylinder in opposite directions. Thus, each sealing ring presses against the inner wall of the cylinder on one side, and a small gap is created between the sealing ring and the inner wall of the cylinder on the other side relative to the longitudinal axis, especially if the sealing ring has shown some wear. The piston ring assembly according to the invention comprises two sealing rings (a first sealing ring and a second sealing ring arranged successively in the longitudinal axis direction), wherein the first sealing ring presses against the inner wall of the cylinder on one side, while the second sealing ring presses against the inner wall of the cylinder on the other side relative to the longitudinal axis. This results in a very good sealing effect in the longitudinal direction, although the piston ring assembly according to the invention is not necessarily completely sealed in the longitudinal axis direction due to the possible small gaps between the sealing ring and the inner wall of the cylinder. Therefore, the piston ring assembly according to the invention is particularly suitable as a so-called pressure isolator arrangement, the task of which is to block or seal pressure peaks that occur during the compression process, and such a pressure isolator arrangement may have some leakage in the longitudinal axis direction. Thus, the piston ring assembly according to the invention has a particular advantage that the dynamically acting pressure can be significantly reduced so that preferably only static pressure is applied to the piston rings arranged along the second section of the piston, and the static pressure is sealed off, rather than the dynamic pressure with a higher pressure portion. The result is a considerably small pressure acting on the piston rings sealing off the static pressure, which greatly increases their service life or operating life.

[0011] The present invention will now be described in detail based on several embodiments. Attached Figure Description

[0012] The accompanying drawings, used to explain the embodiments, show:

[0013] Figure 1 Exploded perspective view of the piston ring assembly;

[0014] Figure 2 Figure 1 A top view of the ring seat shown;

[0015] Figure 3 Figure 1 A top view of the sealing ring shown;

[0016] Figure 4 Figure 2The bottom view of the ring seat shown;

[0017] Figure 5 The section line AA passes through the cutting surface of the ring seat;

[0018] Figure 6 Figure 4 A partial view of the center;

[0019] Figure 7 Passing through the longitudinal section of the piston ring assembly in a relaxed state;

[0020] Figure 8 A longitudinal section passing through the cylinder block, piston, and piston ring assembly arranged within the piston;

[0021] Figure 9 Figure 7 A top view of the piston ring assembly shown;

[0022] Figure 10 Passing through section line BB according to Figure 7 The cross-section of the piston ring assembly;

[0023] Figure 11 According to the section line DD passing through Figure 8 The cross-section of the piston ring assembly;

[0024] Figure 12 According to the section line CC passing through Figure 8 The cross-section of the piston ring assembly;

[0025] Figure 13 according to Figure 8 A partial view of the longitudinal section;

[0026] Figure 14 A side view of a piston in which piston ring assemblies are arranged;

[0027] Figure 15 A longitudinal section through another embodiment of the piston ring assembly in a relaxed state;

[0028] Figure 16 A top view of another embodiment of a piston ring assembly in a relaxed state;

[0029] Figure 17 A partial view through a cross-section of another embodiment of the piston ring assembly;

[0030] Figure 18 A partial view through a cross-section of another embodiment of the piston ring assembly;

[0031] Figure 19 Figure 2A bottom view of another embodiment of the ring seat shown;

[0032] Figure 20 Top view of another embodiment of the sealing ring;

[0033] Figure 21 Passing through the longitudinal section of another piston ring assembly in a relaxed state.

[0034] In principle, identical parts are given the same reference labels in the drawings. Detailed Implementation

[0035] Figure 1 A first embodiment of piston ring assembly 1 is shown, which includes a first continuous sealing ring 2, a second continuous sealing ring 4, and a one-piece or integral ring seat 3.

[0036] Figure 2 Show Figure 1 The diagram shows a plan view of the ring seat 3. The ring seat 3 extends circumferentially about the center point M in the circumferential direction U and has a longitudinal axis L that is perpendicular to the circumferential direction U and extends through the center point M. The ring seat 3 has ends 3a on each side in the circumferential direction U, which are spaced apart from each other in the circumferential direction U and form slits or openings S. The openings S preferably have a width in the circumferential direction U in the range of 1% to 5% of the outer circumference of the sealing ring 2. The sealing ring 2 preferably has a diameter in the range of 30 mm and 250 mm, and therefore preferably has an outer circumference in the range of 94 mm and 785 mm. The ring seat 3 includes a first ring seat web 3e, which extends in the direction of the longitudinal axis L, extends concentrically in the circumferential direction U about the center point M, and has a constant wall thickness D1. The concave inner surface 3g of the first ring seat web 3e has an inner diameter R1, while the convex outer surface 3i of the first ring seat web 3e has a first outer diameter R2. The ring seat 3 also includes an intermediate web 3d that extends radially beyond the first ring seat web 3e relative to the longitudinal axis L. The first ring seat web 3e and the intermediate web 3d form a first recess 3b for receiving the first continuous sealing ring 2. The recess 3b is defined by a support surface 3l extending perpendicular to the longitudinal axis L and a convex outer surface 3i.

[0037] Figure 3 It shows a structure with a first center point M1 and an inner diameter R. D1 and outer diameter R D2 A top view of the first sealing ring 2. Optionally, the sealing ring 2 may also include a fixing part 2c or an anti-rotation device 2c, for example, such as... Figure 3 As shown by the dashed line, the nose protrudes towards the first center point M1. Figure 3A top view of the second sealing ring 4 is also shown, which is identical in design to the first sealing ring 2 in the illustrated embodiment. The second sealing ring 4 has a second center point M2 and also has an inner diameter R. D1 and outer diameter R D2 It may also optionally have a fixing portion 4c. Furthermore, both sealing rings 2 and 4 have outer peripheral surfaces 2a and 4a and inner peripheral surfaces 2d and 4d on their end faces. Preferably, as shown... Figure 3 As shown, the first and second sealing rings 2 and 4 are designed identically. However, the first sealing ring 2 and the second sealing ring 4 can also each have different inner diameters R. D1 .

[0038] Figure 4 Show Figure 2 The diagram shows a top view of the rear side of the ring seat 3. The ring seat 3 is designed to receive first and second sealing rings 2, 4, such that the first and second sealing rings 2, 4 are arranged sequentially in the direction of the longitudinal axis L, and their first and second center points M1, M2 are arranged to be radially and laterally spaced apart or offset from each other relative to the longitudinal axis L. The ring seat 3 includes a second ring seat web 3f, whose concave inner surface 3g extends concentrically in the circumferential direction U relative to the ring seat center point M, so that the common inner surface 3g of the first ring seat web 3e and the second ring seat web 3f respectively have the same concave orientation or the same concave orientation in the direction of the longitudinal axis L. The second ring seat web 3f extends in the circumferential direction U relative to the longitudinal axis L, and also extends in the direction of the longitudinal axis L. The ring seat 3 also includes an intermediate web 3d, which protrudes radially outward from the second ring seat web 3f relative to the longitudinal axis L. The second ring seat web 3f and the intermediate web 3d form a second recess 3c for receiving a second continuous sealing ring 4. The second recess 3c is defined by the supporting surface 3k of the intermediate web 3d extending perpendicularly to the longitudinal axis L and the convex outer surface 3h of the second ring seat web 3f. The concave inner surface 3g of the second ring seat web 3f extends concentrically with the center point M of the ring seat, which in Figure 2 It can also be seen that it has the same inner diameter R1 as the web plate 3e of the first ring seat. Figure 2 The first annular web 3e shown has a constant wall thickness D1 along the circumferential direction U. On the other hand, Figure 4 The second ring seat web 3f shown has a wall thickness that varies along the circumferential direction U. The second ring seat web 3f is designed such that its convex outer surface 3h extends concentrically and circumferentially relative to the third center point M3. For example... Figure 4 As shown and in Figure 6 In even more detail, the third center point M3 is slightly offset to the left relative to the center point M of the ring seat. Figure 4The image shows the ring seat 3 with respect to its symmetry plane N. Since the third center point M3 is slightly offset to the left relative to the center point M of the ring seat, the second ring seat web 3f has a narrower wall thickness D2 than the first ring seat web 3e in the region where the symmetry plane N intersects with the ring seat 3. The wall thickness of the second ring seat web 3f increases from the narrower wall thickness D2 in the symmetry plane N to the wider wall thickness D3 along the circumferential direction U toward the opening S. Figure 4 The diagram shows a first auxiliary line N1 and a second auxiliary line N2, where the first auxiliary line N1 extends through the center point M of the ring seat, and the second auxiliary line N2 extends through the third center point M3. Therefore, in particular, as shown... Figure 6 It can be seen that their offset represents the center distance M between the center point M of the ring seat and the third center point M3. D The center distance M between the first and second center points M1 and M2 of the first and second sealing rings 2 and 4 D Preferably, the range is between 0.1 mm and 10 mm.

[0039] Figure 6 Show Figure 4 A partial detailed view of the center, in which the above-mentioned aspects are shown in magnification, namely, the center point M of the annular seat and the third center point M3 with a center distance M. D They are spaced apart from each other. When the first sealing ring 2 and the second sealing ring 4 are arranged to... Figure 4 When the first sealing ring 2 is placed within the ring seat 3, its first center M1 is the same as the center point M of the ring seat, while the second center M2 of the second sealing ring 4 is the same as the third center point M3. Therefore, the first sealing ring 2 and the second sealing ring 4, arranged within the ring seat 3, are radially fixed to each other relative to the longitudinal axis L by means of a predetermined mutual distance between them. Figure 1 , 2 Figures 4 and 4 show the ring seat 3 in a relaxed state. As described below, the ring seat 3 is elastically deformable, which means that the center distance M between the center point M of the ring seat and the third center point M is... D It can be changed according to the degree of elastic deformation of the ring seat 3.

[0040] Figure 5 Showing according to Figure 4 The section line AA passes through the section plane of the ring seat 3. This specifically shows that the first ring seat web 3e has a wall thickness D1, while the second ring seat web 3f has a narrower wall thickness D2 at section line AA. In other words, relative to the third center point M3, the concentrically and circumferentially extending convex outer surface 3h is shifted to the left relative to the concentrically and circumferentially extending convex outer surface 3i about the center point M of the ring seat. In the selected illustration, the concentrically and circumferentially extending convex outer surface 3i about the center point M of the ring seat is at a center distance M... DShifting to the left in the selected diagram, the orientation of the two convex outer surfaces 3h and 3i determines the center positions of the first and second sealing rings 2 and 4. Therefore, the first center M1 of the first sealing ring 2 and the second center point M2 of the second sealing ring 4 also have a center distance M. D The mutual spacing.

[0041] Figure 7 Show along Figure 4 The symmetry plane N shown passes through a longitudinal section of an embodiment of the piston ring assembly 1, wherein the piston ring assembly 1 is composed of a ring seat 3 and first and second sealing rings 2 and 4. (This is in contrast to the previous description.) Figures 1 to 6 Compared to the previous embodiment, in order to better represent the ring seat 3 and the sealing rings 2 and 4, they are... Figures 7 to 12 The piston ring assembly 1 shown is enlarged, while the inner diameter R1 is shown as reduced. The first and second sealing rings 2, 4, or their first and second center points M1, M2, are offset from each other within the ring seat 3 by a center point distance M. D . Figure 7 The ring seat 3 shown Figure 1 , 2 The ring seat 3 shown in 4, 5, 9 and 10 is in a relaxed state. Figure 7 The outer surfaces arranged opposite to each other relative to the longitudinal axis L are also shown, namely the two outer surfaces 2a and 2b of the first sealing ring 2, the two outer surfaces 4a and 4b of the second sealing ring 4, and the two outer surfaces 3m and 3n of the ring seat 3 and the intermediate web 3d.

[0042] Figure 9 Show Figure 7 The top view of the piston ring assembly 1 shown does not show the intermediate web 3d of the ring seat 3, which is located on which the second sealing ring 4 protrudes radially to the right relative to the longitudinal axis L. Furthermore, Figure 9 The diagram shows the center point M of the ring seat, the first center M1, the second center point M2, the third center point M3, and the center distance M. D .

[0043] Figure 10 Showing the section line BB passing through Figure 7 The cross-section of the piston ring assembly 1 shown. The first ring seat web 3e and the first sealing ring 2 extend concentrically with the ring seat center point M and the longitudinal axis L, respectively.

[0044] like Figure 7As shown, the intermediate web 3d has outer surfaces 3m and 3n extending in the circumferential direction U and pointing radially outward relative to the longitudinal axis L. The first recess 3b has the same radial width about the longitudinal axis L as the first sealing ring 2 to be arranged therein. Therefore, in the view shown in the right figure, the outer surfaces 3m and 2b of the first sealing ring 2 can abut together against the inner wall of the cylinder 11, and during the operation of the piston 10, both outer surfaces 3m and 2b will be worn in the area abutting against the inner wall 11a of the cylinder.

[0045] Figure 8 A longitudinal section through a reciprocating compressor is shown. The compressor includes a cylinder 11 with an inner wall 11a and a piston 10 movably arranged within the cylinder 11 along a longitudinal axis L. The piston 10 is configured as a so-called internal piston and includes a first piston component 10a and a second piston component 10b, wherein the first piston component 10a and the second piston component 10b form an intermediate space in which piston ring assemblies 1 are arranged. The piston 10 may include a plurality of piston components 10a, 10b, and particularly a plurality of piston ring assemblies 1 arranged sequentially within the intermediate space along their longitudinal axis L. Figure 7 As shown, in order to Figure 7 The piston ring assembly 1 shown is introduced into the cylinder body 11. A force F must be applied along both sides of the piston ring assembly 1 to the first and second sealing rings 2, 4 and / or the ring seat 3, thereby causing the ring seat 3 to elastically deform and thus reducing the distance M between the centers of the sealing rings 2, 4. D That is, the radial distance between the first center point M1 of the first sealing ring 2 and the second center point M2 of the second sealing ring 4 relative to the longitudinal axis L, so that they can be accommodated within the cylinder body 11. The elastic deformation of the ring seat 3 causes it to apply a reaction force to the sealing rings 2 and 4. Figure 8 In the embodiment shown, the ring seat 3 will apply the first radial force F R1 The force applied to the second sealing ring 4, and simultaneously the ring seat 3 acting in the opposite direction, is the second radial force F. R2 The force is applied to the first sealing ring 2. Since the second sealing ring 4 contacts the left-side ring seat 3 via its convex outer surface 3h, the second sealing ring 4 applies a radial force F to the left, as shown in the view, acting on the inner wall 11a of the cylinder body. R3 Due to the elastic deformation of the ring seat 3, a gap is formed on the right side between the convex outer surface 3h and the second sealing ring 4. Since the first sealing ring 2 contacts the ring seat 3 on the right side through the convex outer surface 3i, the first sealing ring 2 applies a radial force F to the right, as shown in the view, acting on the inner wall 11a of the cylinder body. R4Due to the elastic deformation of the ring seat 3, a gap is formed on the left side between the convex outer surface 3i and the first sealing ring 2. Therefore, the piston ring assembly 1 according to the invention has the characteristic that the first sealing ring 2 presses against the inner wall 11a of the cylinder with its outer surface 2b, while the second sealing ring 4 presses against the other side of the inner wall 11a of the cylinder with its outer surface 4b. Figure 11 Show Figure 8 The diagram shows a top view of the piston ring assembly 1 from the DD cross-sectional direction, excluding the first piston component 10a, the second piston component 10b, and the cylinder 11. Deformation of the ring seat 3 results in a gap forming on the right side between the second sealing ring 4 and the convex outer surface 3h, thus making the support surface 3k, extending perpendicularly to the longitudinal axis L, visible. Figure 12 Showing the section line CC passing through Figure 8 The cross-section of the piston ring assembly 1 shown is illustrated, but the first piston component 10a, second piston component 10b, and cylinder 11 are not shown. Deformation of the ring seat 3 results in a gap forming on the left side between the first sealing ring 2 and the convex outer surface 3i. Figure 11 and 12 In the diagram, the deformation of the ring seat 3 is not shown to scale, but is only for illustration.

[0046] Figure 13 Show Figure 8 The image shows a slightly enlarged portion of the longitudinal section. The first and second sealing rings 2 and 4 are new, or have an outer diameter equal to the inner diameter of the cylinder body 11, and preferably have an outer diameter smaller than the inner diameter of the cylinder body 11, preferably at least 0.1% smaller, particularly preferably at least 3% smaller. The cylinder body 11 preferably has an inner diameter in the range of 30 mm to 250 mm. Figure 8 As shown in the view, the ring seat 3 presses the second sealing ring 4 against the inner wall 11a of the cylinder on the left side, therefore, as Figure 13 As shown, a gap S1 is formed between the inner wall 11a of the cylinder on the right side and the outer surface 4a of the second sealing ring 4. Figure 8 As shown, the first sealing ring 2 is pressed against the inner wall 11a of the cylinder on the right side by the ring seat 3 in the opposite direction. Therefore, on the inner wall 11a of the cylinder on the left side (where it is located...) Figure 13 A gap S1 (not shown) is formed between the first sealing ring 2 and the second sealing ring 2.

[0047] Before the piston ring assembly 1 according to the invention is inserted into the cylinder 11, the ring seat 3 must be elastically deformed so that the piston ring assembly fits into the cylinder 11. Figure 8 and 13 As shown, after being inserted into the cylinder 11, the piston ring assembly 1 is clamped between the inner walls 11a of the cylinder 11. Figure 8As shown, during the decompression state of the reciprocating compressor, i.e. when the compressor is stopped and the piston 10 is stationary, the first sealing ring 2 and the second sealing ring 4 respectively exert force F R3 and F R4 The first sealing ring 2 and the second sealing ring 4 press against the inner wall 11a of the cylinder body in opposite directions. The design of the ring seat 3 and its elastic deformation within the cylinder body 11 ensure that the first sealing ring 2 and the second sealing ring 4 press against the inner wall 11a of the cylinder body in a static state. Therefore, the first sealing ring 2 and the second sealing ring 4 are in their initial positions in a static state, which is important for the subsequent compression process. If Figure 8 The piston 10 shown moves upward, or if the compression chamber 14 contracts due to the movement of the piston 10, compressing the contents of the compression chamber 14, this will cause an increase in the pressure of the fluid located within the compression chamber 14. This increase in pressure causes the first sealing ring 2 and the second sealing ring 4 to exert greater forces F, respectively. R3 and F R4 The sealing rings 2 and 4 are pressed against the inner wall 11a of the cylinder, thus ensuring sufficient contact force between the sealing rings 2 and 4 and the inner wall 11a of the cylinder, even if the fluid to be compressed has a higher pressure.

[0048] The piston ring assembly 1 according to the invention includes a first sealing ring 2 and a second continuous sealing ring 4, both sealing rings 2 and 4 being annular and continuous, i.e., extending 360° in the circumferential direction without any openings. This annular design has the advantage of allowing for particularly stable design of the first and second sealing rings 2 and 4, and also allows for increased strength of the sealing rings 2 and 4 by selecting materials adapted to the applied pressure, thus preventing cold flow of the sealing rings 2 and 4. Therefore, the piston ring assembly 1 according to the invention is also particularly suitable for compressing fluids to very high final pressures, for example, up to 500 bar, especially for compressing hydrogen. Such sealing rings are made of wear-resistant materials, particularly metals such as copper, gray cast iron, or sintered iron, or plastics such as polytetrafluoroethylene (PTFE), filled polytetrafluoroethylene (PTFE), or high-temperature polymers such as polyetheretherketone (PEEK), polyimide (PI), or epoxy resin.

[0049] The ring seat 3 may, but does not need to, be made of a wear-resistant material. The ring seat 3 is preferably made of metal, particularly steel, stainless steel, copper or gray cast iron, or of plastic, particularly of polytetrafluoroethylene (PTFE), filled polytetrafluoroethylene (PTFE) or high-temperature polymers such as polyetheretherketone (PEEK), polyimide (PI) or epoxy resin.

[0050] Figure 14A side view of a piston 10 extending along the longitudinal axis L is shown. The cylinder body 11 is not shown, and the piston 10 defines a compression chamber 14. Starting from the compression chamber 14, the piston 10 has a first partial section A1 along the longitudinal axis L, followed by a second partial section A2, wherein at least one piston ring assembly 1 is arranged along the first partial section A1. In the illustrated embodiment, four piston ring assemblies 1 are spaced apart from each other along the longitudinal axis L, and at least one piston ring 13 that seals static pressure is arranged along the second partial section A2. In the illustrated embodiment, five piston rings 13 are spaced apart from each other along the longitudinal axis L. Furthermore, guide rings 15 are also arranged to the piston 10. Such piston rings 13 that seal static pressure have been disclosed, for example, in documents EP1275888A1 or WO2018 / 108464A1. Preferably, at least one piston ring assembly 1 at least reduces the dynamic pressure portion. Preferably, the pressure present in the compression chamber 14 is reduced in the longitudinal direction L of the piston 10 in two different ways, wherein in the longitudinal axial direction L, starting from the compression chamber 14, the dynamic pressure portion is reduced along the first local section A1 of the piston 10, and wherein the static pressure portion is reduced in the subsequent second local section A2.

[0051] Figure 15 Another embodiment of piston ring assembly 1 is shown. (Compared to...) Figure 7 Compared to the embodiments shown, Figure 15 In the embodiment shown, the ring seat 3 has a smaller outer diameter, thus the outer surface 3m is displaced towards the longitudinal axis L. The outer diameter of the ring seat 3 is smaller than the outer diameter of the piston ring assembly 1. This embodiment has the advantage of ensuring that only the first sealing ring 2 and the second sealing ring 4 can contact the inner wall 11a of the cylinder, or the advantage of ensuring that the reaction force F caused by the inner wall 11a of the cylinder is transmitted to the piston ring assembly 1 entirely through the first sealing ring 2 and the second sealing ring 4.

[0052] like Figure 15 As shown, it may prove advantageous to provide a spring 12 for the piston ring assembly 1, which applies a radially outward force relative to the longitudinal axis L on the ring seat 3. Figure 15 The illustrated embodiment shows a spring 12 extending in the circumferential direction U, and this spring is preferably arranged within a groove 3o extending in the circumferential direction U, and is placed within the recessed inner surface 3g of the ring seat 3. The spring 12 may extend along a portion or the entire circumference of the inner surface 3g.

[0053] Figure 16 A top view of another embodiment of the ring seat 3 is shown, which is a continuous or one-piece design, and particularly a ring design, thus relating to... Figure 2Compared to the embodiment shown, it does not have an opening or opening S. By appropriately selecting an elastic material, it is possible to give the ring seat 3 such elastic properties, thereby eliminating the need for the opening S in the ring seat 3.

[0054] Figure 17 and 18 Partial cross-sectional views are shown for each of two embodiments of the piston ring assembly 1, wherein a first sealing ring 2 and a second sealing ring 4 are arranged sequentially along the longitudinal axis L and disposed within the ring seat 3. Preferably, the first and second sealing rings 2 and 4 are in contact with each other in the direction of the longitudinal axis L.

[0055] The first and / or second sealing rings 2, 4 of the piston ring assembly 1 preferably have the same width in the radial direction along the entire circumference relative to the longitudinal axis L, but in another possible embodiment, the width in the circumferential direction may also vary.

[0056] Figure 19 A bottom view showing another embodiment of the ring seat 3, the upper side of which is designed as follows: Figure 2 As shown in the diagram. Therefore, the upper and lower sides of such a ring seat 3 are identical. Figure 20 A top view showing another embodiment of the second sealing ring 4. (Compared to...) Figure 3 The second sealing ring 4, in which the inner circumferential surface 4d and the outer circumferential surface 4a have the same second center point M2, are different, according to Figure 20 In one embodiment, the inner peripheral surface 4d or its fourth center M4 is displaced relative to the outer peripheral surface 4a or its second center point M2. The inner peripheral surface 4d thus extends eccentrically relative to the outer peripheral surface 4a. Figure 21 A longitudinal section is shown through the piston ring assembly 1 in a relaxed state, wherein the shapes of the two sides of the ring seat 3 are similar to... Figure 19 and Figure 2 The same as shown, and wherein the shape of the first sealing ring 2 is as shown. Figure 3 As shown in the figure, the shape of the second sealing ring 4 is as follows: Figure 20 As shown in the diagram, the ring seat 3 has a center point M and a longitudinal axis L. The first center point M1 of the first sealing ring 2 is located at the same position as the center point M along the longitudinal axis L, while the second center point M2 of the second sealing ring 4 is offset to the left by a distance M from the center point in the view shown. d .like Figure 7 As shown, the technical effect of the first and second center points M1 and M2 of the first and second sealing rings 2 and 4 being radially spaced relative to the longitudinal axis L can be achieved through the following facts: Figure 20 As shown, the first and second recesses 3b and 3c and their convex outer surfaces 3h and 3i have radial displacement relative to the longitudinal axis L and / or the first and / or second sealing rings 2 and 4, each having an inner peripheral surface 4d and an outer peripheral surface 4a, have radial displacement. Figure 7 and21 Two embodiments of piston ring assembly 1 are shown, whose outer peripheral surfaces 2a and 4a extend similarly and have the same center distance M radially relative to the longitudinal axis L. d . Figure 21 The piston ring assembly 1 shown can be used with Figure 8 They are arranged in the same manner inside the cylinder body 11. In another possible embodiment, the first and second sealing rings 2 and 4 can be arranged as follows: Figure 20 The structure is eccentrically arranged as shown. Preferably, the first and / or second sealing rings 2, 4 include an anti-rotation device 4c, which is as follows: Figure 20 As shown, the device may, for example, have a nose-shaped structure. In another embodiment, the inner circumferential surfaces 2d, 4d of the first and / or second sealing rings 2, 4 and the convex outer surfaces 3i, 3h of the ring seat 3 may not have the circumferential orientation shown, but may have, for example, an elliptical, polygonal, or toothed orientation, so that the mutual formation of the ring seat 3 and the first and / or second sealing rings 2, 4 forms an anti-rotation device.

Claims

1. A piston ring assembly (1) comprising a first continuous sealing ring and a second continuous sealing ring (2, 4) and an elastic ring seat (3), wherein the first continuous sealing ring and the second continuous sealing ring (2, 4) extend in a circumferential direction (U) and each has an outer peripheral surface (2a, 4a), the first continuous sealing ring (2) having a first center point (M1) relative to its outer peripheral surface (2a) and the second continuous sealing ring (4) having a second center point (M2) relative to its outer peripheral surface (4a), the first continuous sealing ring and the second continuous sealing ring (2, 4) each having a longitudinal axis (L) extending perpendicular to the circumferential direction (U), wherein the ring seat (3) extends in the circumferential direction (U), and wherein the ring seat (3) and the first continuous sealing ring and the second continuous sealing ring (2, 4) are designed to be mutually adapted such that the first continuous sealing ring and the second continuous sealing ring (2, 4) are successively arranged in the ring seat (3) in the direction of the longitudinal axis (L), and such that their first center point and second center point (M1, M2) are mutually adapted to each other. M2) are arranged radially spaced apart from each other relative to the longitudinal axis (L), characterized in that, When the piston ring assembly (1) is intended to be used, the sealing rings (2, 4) press against the inner wall (11a) of the cylinder body (11) in opposite directions. The ring seat (3) includes a first recess (3b) for receiving the first continuous sealing ring (2) and a second recess (3c) for receiving the second continuous sealing ring (4). The first recess (3b) and the second recess (3c) are offset from each other in the direction of the longitudinal axis (L) and in the radial direction relative to the longitudinal axis (L).

2. The piston ring assembly according to claim 1, characterized in that, The ring seat (3) is designed as a one-piece unit.

3. The piston ring assembly according to claim 1 or 2, characterized in that, The ring seat (3) has an opening (S) with a slit in the circumferential direction (U).

4. The piston ring assembly according to claim 1, characterized in that, The ring seat (3) has an intermediate web (3d) extending radially relative to the longitudinal axis (L), wherein the first continuous sealing ring and the second continuous sealing ring (2, 4) abut against the intermediate web (3d) spaced apart from each other along the longitudinal axis (L).

5. The piston ring assembly according to claim 1, characterized in that, The first center point and the second center point (M1, M2) have a radial distance between each other of 0.1 mm and 10 mm relative to the longitudinal axis (L).

6. The piston ring according to claim 1, characterized in that, It includes a spring (12) extending in the circumferential direction (U) that applies an outward force to the ring seat (3) relative to the longitudinal axis (L).

7. The piston ring according to claim 1, characterized in that, The sealing rings (2, 4) are made of wear-resistant material, and / or the ring seat (3) is made of metal.

8. The piston ring according to claim 1, characterized in that, The first continuous sealing ring and / or the second continuous sealing ring (2, 4) protrude outward beyond the ring seat (3) in the direction of the longitudinal axis (L).

9. The piston ring according to claim 1, characterized in that, The first continuous sealing ring and the second continuous sealing ring (2, 4) are arranged one after the other along the longitudinal axis (L).

10. Use of the piston ring assembly according to claim 1 as a pressure barrier for sealing dynamic pressure portions.

11. A piston compressor including a cylinder (11), comprising a piston (10) disposed within the cylinder (11), and comprising at least one piston ring assembly (1) disposed to the piston (10) according to any one of the preceding claims.

12. The reciprocating compressor according to claim 11, characterized in that, The first and second continuous sealing rings (2, 4) in their new state have an outer diameter (R) that is at least 0.1% smaller than the inner diameter of the cylinder body (11). D2 ).

13. The reciprocating compressor according to claim 11 or 12, characterized in that, The cylinder (11) and the piston (10) define a compression chamber (14), wherein the piston (10) has a first partial section (A1) and a second partial section (A2) in the longitudinal axis (L) direction starting from the compression chamber (14), wherein at least one piston ring assembly (1) is arranged along the first partial section (A1), and wherein at least one piston ring (13) for sealing static pressure is arranged along the second partial section (A2).

14. A method for sealing a compression chamber (14), the compression chamber being defined by a cylinder (11) and a piston (10) disposed therein and movable in the direction of a longitudinal axis (L), wherein a first continuous sealing ring and a second continuous sealing ring (2, 4) are disposed to the piston (10), wherein the first continuous sealing ring and the second continuous sealing ring (2, 4) press against the inner wall (11a) of the cylinder (11) in opposite directions transverse to the longitudinal axis (L) in a stationary state, and wherein the first continuous sealing ring and the second continuous sealing ring (2, 4) additionally press against the inner wall (11a) of the cylinder (11) in opposite directions by an internal pressure increased within the compression chamber (14) of the cylinder (11) during a compression phase of the piston (10).

15. The method according to claim 14, characterized in that, The pressure along the piston (10) is reduced in two different ways, wherein in the direction of the longitudinal axis (L), starting from the compression chamber (14), the dynamic pressure portion is reduced along the first local section (A1) of the piston (10), and wherein the static pressure portion is reduced in the subsequent second local section (A2).

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