Sealing ring with relief opening

Abstract

In order to provide a sealing ring (14) which is constructed as simply and compactly as possible, which can achieve a longer service life and can be flexibly adapted to different conditions of use, the invention provides that at least three relief openings (25) are provided on at least one ring segment (14a), preferably on each ring segment (14a), the relief openings extending from a radially inner inner circumference (18) of the ring segment (14a) to a radially outer outer circumference (23) and / or to a second axial ring end (RE2) of the ring segment (14a), wherein the relief openings (25) each have a central opening opening which opens into the ring segment (14a). ), wherein the first relief opening ends (25a) of the two relief openings (25) arranged side by side in the circumferential direction are spaced apart from each other by a relief opening circumferential spacing (z), wherein the first relief opening end (25a) is closer to the first axial ring end (RE1) than the second axial ring end (RE2) in the axial direction and is spaced apart from the first axial ring end (RE1) by a relief opening axial spacing (x), and the relief opening axial spacing is between 4% and 20% of the axial ring width (RB) of the ring segment (14a).

Description

Technical Field

[0001] The present invention relates to a sealing ring having at least three ring segments, each ring segment having a first segment end and a second segment end in the circumferential direction, wherein a first tangential contact surface of a first segment end of a ring segment abuts against a second tangential contact surface of a second segment end of a ring segment connected to the ring segment in the circumferential direction, so as to produce a radial seal of the sealing ring, and a first axial contact surface of a first segment end of a ring segment facing a first axial ring end of the sealing ring abuts against a second axial contact surface of a second segment end of a ring segment connected to the ring segment in the circumferential direction, so as to produce an axial seal of the sealing ring. In addition, the present invention relates to a sealing device for sealing a piston rod that moves in a translational reciprocating manner, the sealing device having a housing in which a plurality of sealing rings arranged successively in the axial direction are arranged; and a piston compressor having a compressor housing and at least one cylinder housing arranged on the compressor housing, in which a piston performs a translational reciprocating motion. Background Art

[0002] A piston compressor using a crosshead construction, especially a double-acting construction, requires a compression space on the crank side to be sealed along the reciprocating piston rod in the cylinder, in which there is a (high) cylinder pressure that varies with time. This sealing is usually performed relative to the (low) pressure present in the crankcase, which is substantially equal to the ambient pressure. The sealing element used in this sealing device is called a sealing ring and is arranged in a so-called pressure sealing body. Here, the sealing element can follow the lateral movement of the piston rod to a certain extent without losing its sealing effect. In order to improve the service life and reliability of the pressure sealing body, a plurality of such sealing rings are usually connected in series in the axial direction in the pressure sealing body. This pressure sealing body or sealing device is fully known from the prior art with very different construction schemes, for example from GB928749A, US1008655A or EP2056003A1.

[0003] Due to the relative movement between the piston rod and the sealing ring, the sealing ring is subject to a certain amount of wear on the contact surface with the piston rod. This ring wear usually requires a split ring shape, which requires the ring to adjust itself continuously in the case of material wear on the ring / piston rod contact surface. For this purpose, radially and tangentially split rings are mostly used, which are embedded in pairs in the sealing chamber of the pressure sealing body in order to cover the joint gaps that occur with each other in order to compensate for the wear. This radial / tangentially split ring combination is a single-acting sealing device, which only seals in the direction of the crosshead, while during the re-expansion phase on the crank side of the piston compressor, the radial cutouts ensure that higher pressures are not enclosed in the sealing body. As is known, in the case of split ring shapes, a hose spring wound on the outer circumference is usually used, which also presses the sealing ring against the piston rod in the pressure-free state.

[0004] In particular, at relatively high pressures, the sealing ring may be significantly squeezed into the gap formed between the piston rod and the sealing housing or the cavity disk in conventional assemblies. In order to avoid such squeezing as much as possible, an additional metallic support ring that contacts the piston rod in a non-planar manner may be used between the ring on the low-pressure side and the cavity disk, as disclosed, for example, in US Pat. No. 3,305,241 A.

[0005] In the case of a combination of a radially and tangentially split sealing ring, the seal towards the piston rod is essentially only achieved by the tangentially split sealing ring, whose ring segments can slide together in the event of wear via the tangentially split guide and thus retain the sealing effect. The radially split sealing ring is essentially only used to seal the wear gap of the tangential sealing ring in the axial direction and in the radial direction. The radial sealing ring is only worn to the extent that the ring segments are in contact with each other in the circumferential direction. As a result, the wear of the radially and tangentially split sealing rings is different. In order to prevent the radially and tangentially split sealing rings from twisting relative to each other, which could result in the wear gap of the tangentially split sealing ring no longer being covered and thus possibly losing the sealing effect, anti-twist devices must be provided between the rings. Such anti-twist devices are usually implemented as pins, which are inserted into recesses provided in the radially and tangentially split sealing rings. Therefore, it has been proposed in EP2056003A1 that instead of providing a sealing ring combination consisting of a radially and tangentially split sealing ring, only a single sealing ring is provided, which is not only radially but also tangentially split. This can reduce the axial construction length of the pressure seal body and thus the axial construction length of the entire sealing device.

[0006] As the compression pressure of the compressor increases, the load on the sealing ring and therefore its wear will also increase. A known method for reducing the load on the segmented sealing ring is to provide a pressure compensation device, such as shown in EP2056003A1. Here, the existing higher pressure is introduced into the dynamic sealing surface (radially between the sealing ring and the piston rod) via one or more pressure compensation grooves extending in the circumferential direction and axially closer to the side (crankcase side) facing away from the pressure. The pressure per unit area in the dynamic sealing surface is thereby reduced, the friction power is reduced, and the service life is increased. However, it is disadvantageous here that the principle of the pressure compensation can only be improved to a certain extent, because due to the pressure compensation groove, the residual wall thickness of the sealing ring remaining in the axial direction is no longer stable enough and may deform and leak due to the existing pressure. Another disadvantage of the highly pressure-compensated sealing ring is that the ring is pressed radially onto the piston rod only with a small residual force. Since the piston rod generally also performs a certain lateral movement in addition to the translational reciprocating movement, the friction forces on the axial contact surface of the sealing ring may hinder or at least delay the radial movement of the ring, which may cause the ring to lift off the piston rod and cause leakage associated therewith.

[0007] CH439897A shows a three-piece tangentially split sealing ring. Three holes are provided on the ring segment as throttling points, which are centrally arranged between the end faces. A separate cover ring is required for axial sealing. US3305241 discloses a three-piece tangentially split sealing ring, wherein two radial holes are centrally arranged between the two end faces on each ring segment. The holes merge into a circumferential groove on the inner circumference. A separate cover ring is also required here for axial sealing. US1828178 discloses not a sealing ring for sealing, but a tangentially split three-piece oil scraper ring. A circumferential groove is provided on the inner circumference, which is connected to the axial end face via an opening. The oil scraped off the piston rod is discharged to the outside through the openings. KR101898141B1 discloses a four-piece sealing ring with axial and tangential sealing devices. Each ring segment is also provided with a central unloading hole. Summary of the invention

[0008] Therefore, the object of the present invention is to provide a sealing ring and a sealing device which eliminate the disadvantages of the prior art. In particular, the sealing ring should be as simple and compact as possible, achieve a longer service life and be flexibly adaptable to different conditions of use.

[0009] According to the invention, this object is achieved in that at least three relief openings are provided on at least one ring segment, preferably on each ring segment, the relief openings extending from the radially inner inner circumferential surface of the ring segment to the radially outer outer circumferential surface and / or to the second axial ring end of the ring segment, wherein the relief openings each have a first relief opening end which opens into the radially inner inner circumferential surface of the ring segment, wherein the first relief opening ends of two relief openings arranged side by side in the circumferential direction are arranged spaced apart from each other by a relief opening circumferential spacing, wherein the first relief opening end is closer to the first axial ring end in the axial direction than the second axial ring end and is spaced apart from the first axial ring end by an axial relief opening spacing which is 4% to 20% of the axial ring width of the ring segment. This provides a sealing ring which, in the assembled state, during operation of the compressor, enables pressure compensation between the high pressure present at the outer circumferential surface and the second axial ring end and the relatively lower pressure present at the first axial ring end.

[0010] Preferably, the circumferential spacing of the relief openings is 1 mm to 15 mm, particularly preferably 2 mm, and the circumferential spacing of the relief openings between all relief openings in the same ring segment is preferably equal. This can improve pressure compensation, especially more uniform pressure compensation in the circumferential direction.

[0011] Preferably, the at least one relief opening has a relief opening length in the circumferential direction at least at the relief opening end, which is 2-100%, preferably 2-50%, in particular a maximum of 25% of the axial ring width of the sealing ring. Thus, for example, a groove-like recess extending in the circumferential direction in a relatively small area can be provided on the inner circumference. Preferably, at least one section of the radially inner inner circumference of the at least one relief opening adjacent to the sealing ring is inclined or curved in the direction of the first axial ring end. As a result, the pressure compensation can be adjusted, in particular increased, depending on the radial wear of the sealing ring.

[0012] Advantageously, at least one relief opening is provided, whose first relief opening end, which opens into the radially inner inner circumferential surface of the sealing ring, is spaced apart in the circumferential direction from its second relief opening end, which opens into the radially outer outer circumferential surface of the sealing ring. Thus, for example, a relief hole can be provided in the region of the first segment end on the inner inner circumferential surface, which extends obliquely from the inner inner circumferential surface to the outer circumferential surface of the sealing ring.

[0013] Advantageously, at least one axial groove is provided on the radially outer peripheral surface of at least one ring segment, preferably each ring segment, which extends from the first axial ring end to the second axial ring end. This makes it possible to improve the structural rigidity of the ring segment and thus the sealing ring.

[0014] Preferably, the at least three relief openings each have an axial relief opening width at least at their relief opening ends, which is 2-30%, preferably 2-20%, of the axial ring width of the sealing ring. Advantageously, at least one relief opening has a straight extension and a constant circular cross section with a relief opening diameter of between 2-30%, preferably between 2-20%, of the axial ring width of the sealing ring. As a result, the relief opening can be produced simply, for example by drilling or milling, wherein said dimensions have proven to be advantageous for achieving the best possible pressure compensation.

[0015] According to a further advantageous embodiment, at least one wear opening is provided on at least one ring segment, the wear opening extending from the radially outer circumference of the ring segment and / or the second axial ring end in the direction of the radially inner inner circumference of the ring segment, wherein the radially inner wear opening end of the at least one wear opening facing the inner circumference is spaced apart from the radially inner inner circumference of the ring segment in the radial direction of the ring segment by a distance of at most 40% of the radial ring height extending between the outer circumference and the radially inner inner circumference of the ring segment, wherein the wear opening end is located between the first and second axial ring ends and is spaced apart from the first and second axial ring ends. As a result, starting from a specific wear state in which the wear opening on the radially inner inner circumference of the sealing ring is exposed, the pressure compensation can be further increased and the contact force can be reduced.

[0016] Advantageously, at least one end section of the at least one wear opening facing the radially inner inner circumferential surface is inclined in the direction of the first axial ring end. As a result, starting from the exposure of the wear opening on the radially inner inner circumferential surface of the sealing ring, the pressure compensation properties can be adjusted, in particular improved, as a function of increasing radial wear of the sealing ring, similar to the case of an inclined relief opening.

[0017] Advantageously, at least one wear opening has a straight extension and a circular cross section with a wear opening diameter that is 2-60%, preferably 2-40%, of the axial ring width of the sealing ring. The wear opening can thus be produced simply, for example by drilling or milling, wherein these dimensions have proven to be advantageous for achieving the best possible pressure compensation.

[0018] Preferably, the delimitation of the at least one wear opening toward the first axial ring end is spaced apart from the first axial ring end in the axial direction by a wear opening axial spacing of 2% to 20%, preferably 2-15%, of the axial ring width. This makes it possible to improve the pressure compensation without unacceptably reducing the stability of the sealing ring.

[0019] According to a further advantageous embodiment, at least one compensating recess is provided on at least one ring segment, the compensating recess extending from the radially outer outer circumference of the ring segment in the direction of the radially inner inner circumference of the ring segment and from the first axial ring end in the direction of the second axial ring end, preferably at least one compensating recess is provided on each ring segment. As a result, the pressing force on the wall and thus the friction in the radial direction can be reduced, so that the sealing ring can better follow the lateral movement of the piston rod.

[0020] Furthermore, it is advantageous if at least one starting recess is provided on the radially inner inner circumference of at least one ring segment, the starting recess extending in the axial direction of the ring segment from the second axial ring end in the direction of the first axial ring end and in the radial direction of the ring segment from the radially inner inner circumference of the ring segment in the direction of the radially outer outer circumference of the ring segment, wherein the starting recess has a radial starting recess depth which is a maximum of 3% of the ring height. As a result, an increased surface area pressure can be generated during the start-up phase of the compressor on the radially inner inner circumference of the sealing ring which is not covered by the starting recess, which is particularly advantageous for reducing leakage during the start-up phase in the case of highly pressure-compensated sealing rings.

[0021] Furthermore, the object is achieved by a sealing arrangement, in which at least one sealing ring according to the invention is provided in the sealing arrangement, and by a piston compressor, in which at least one sealing ring according to the invention is provided in a compressor housing. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Please refer to the following Figure 1 To Attachment Figure 8d The present invention will be described in more detail. The drawings show advantageous structural solutions of the present invention by way of example, schematically and not restrictively. The drawings are as follows:

[0023] Figure 1 A sealing device for a piston rod is shown,

[0024] Figure 2 The sealing ring is shown in an isometric view,

[0025] Figure 3a and Figure 3bThe sealing ring or the ring segment is shown in a top view of a first axial ring end.

[0026] Figure 4a and Figure 4b The sealing ring or the ring segment is shown in a top view of the second axial ring end.

[0027] Figure 5a and Figure 5b Shows the pressure on the sealing ring,

[0028] Figure 6 The sealing ring is shown in a top view of the outer circumference and in cross-sectional views at different positions of the sealing ring.

[0029] Figures 7a to 7d respectively show ring segments of a sealing ring with compensating recesses of different designs,

[0030] Figures 8a to 8d The ring segments of a sealing ring with a starting section are shown in different views. DETAILED DESCRIPTION

[0031] Figure 1 , a sealing device 1 (pressure seal) known from the prior art is shown, which is used for a piston rod 2 with a translational reciprocating motion, for example the piston rod of a well-known piston compressor with a crosshead (not shown). The piston rod 2 basically performs a translational reciprocating motion, as indicated by the double arrow. The translational motion is generated by the crosshead construction method of the known piston machine, which is particularly used for large, relatively slow-running piston machines, for example for gas compressors or large diesel engines. Here, the lateral force of the push rod is supported on a so-called crosshead hinge, which is supported in the crankcase. As a result, the piston, which is fixed to the crosshead by means of the piston rod, only performs a basically translational motion. The design of the crosshead is known in principle, so it will not be discussed in more detail here. However, pure translational motion is understood here to mean that the piston rod 2 may also undergo a small lateral motion.

[0032] In the assembled state, the sealing device 1 is arranged in the piston compressor so that the first axial sealing end AE1 faces the piston arranged in the cylinder of the piston compressor (not shown) in the axial direction. The opposite second axial sealing end AE2 of the sealing device 1 faces the crankcase of the piston compressor. Therefore, the sealing device 1 is used to transfer the high pressure P at the first sealing end AE1 (in the cylinder) to the piston. H Relative to the lower pressure P at the second sealing end AE2 (in the crankcase) NSealing, this relatively low pressure is substantially equal to the ambient pressure or possibly slightly higher. It is very important to achieve the best possible sealing effect in order to ensure that as little compressed medium as possible can leave the cylinder into the crankcase and from there into the surroundings under certain circumstances. This is particularly important in the case of gas compressors, for example in the case of gas compressors for compressing natural gas, in order to avoid the formation of a flammable mixture of gas and air outside the compressor, which could under certain circumstances lead to fire or explosion. In addition, for safety reasons, the best possible sealing is required in order not to endanger people around the compressor. In addition, the best possible sealing contributes to increasing the delivery volume and thus the efficiency of the compressor.

[0033] The sealing device 1 usually has a housing 3 which is essentially cylindrical and can be assembled, for example, from a number i of housing segments 3i (also called cavity disks) arranged one after another in the axial direction. In the example shown, the sealing device 1 has a plurality of cavities 4 facing the connecting rod 2, which are formed here by recesses in the housing segments 3i. In each cavity 4, one or more sealing rings 7a-7c in different embodiments are arranged, for example, the combination of radially split sealing rings and tangentially split sealing rings mentioned at the beginning, or, as shown, a radially / tangentially split combined sealing ring 7b. In order to avoid squeezing of the sealing rings 7a-c, a support ring 8 can also be arranged axially next to each sealing ring 7a-c, which support ring is made of a suitable metal, for example. The sealing device 1 shown has three different types of sealing rings 7, wherein a so-called pressure breaking ring or "pressure breaking member (pressure breaker)" is provided as the first sealing ring 7a adjacent to the cylinder, which is used to reduce the flow velocity of the gas. Two sealing rings 7b are arranged adjacent to the sealing ring 7a in the direction of the crankcase, respectively, in a chamber 4b. These sealing rings 7b are common combined radial / tangential split sealing rings here. The sealing rings 7c immediately following in the axial direction are respectively arranged in a chamber 4c, and in the example shown, the sealing rings 7c are separated from the chamber 4b or the sealing rings 7b arranged therein by the buffer chamber 4e. The sealing ring 7c constitutes a sealing barrier in the illustrated embodiment, as described in EP2376819B1 or EP2855982B1, for example. For this purpose, a sealing medium under pressure, such as sealing oil, is conveyed into the chamber 4c via the inlet pipe 9. The sealing medium can be output via the outlet pipe 10 to realize circulation. Due to the sealing medium, each sealing ring 7c is subjected to oil pressure loading from the radial outside and in the axial direction and is pressed against the piston rod 2 by the oil pressure and separated from each other in the axial direction to produce or improve the seal. And each sealing ring 7b is held on the piston rod 2 by means of a hose spring 11 arranged on the circumference and is pressed against the piston rod 2 during operation due to the pressure difference. However, the sealing by means of the sealing barrier by means of the sealing ring 7 c is shown only for the sake of completeness and is not essential to the invention.

[0034] At the second axial sealing end AE2 of the sealing device 1, two scraper rings 13 are arranged next to the sealing ring 7c, which are provided for scraping and collecting the sealing medium adhering to the piston rod 2. The scraper rings 13 scrape the sealing medium and discharge it radially outward into the chamber 4d. The sealing medium is discharged from the chamber 4d by means of the collecting pipe 12, then filtered, collected in a storage container and fed back to the sealing ring 7b.

[0035] Figure 1The sealing device 1 in the embodiment is of course only exemplary and can be embodied in any different manner, in particular with other arrangements of sealing rings 7a-c and / or scraper rings 13. For example, it is also possible to completely dispense with the use of housing segments 3i and buffer chambers 4e for forming chambers 4c for sealing by means of sealing barriers, and to provide only housing segments 3i with chambers 4b for sealing rings 7b and one or more chambers 4d for scraper rings 13 in the sealing device 1. According to the invention, at least one sealing ring 14 embodied according to the invention, which is described below, is provided in the sealing device 1.

[0036] According to the following Figures 2 to 8d The sealing ring 14 according to the invention described herein relates, for example, to Figure 1 1 is one of the sealing rings 7b shown in FIG. However, the sealing device 1 shown is of course to be understood only as an example, for explaining the application of the sealing ring 14 according to the present invention. The sealing device 1 may of course also have more or fewer dry-running sealing rings 7a (pressure breaking rings), sealing rings 7b, sealing rings 7c loaded with sealing medium, and scraper rings 13, for example, only one or more dry-running sealing rings 7b, wherein at least one sealing ring 14 according to the present invention is provided.

[0037] Figure 2 1 shows a sealing ring 14 according to the invention. The sealing ring 14 has a central opening 15 which is substantially cylindrical and which, in the assembled state, for example, is engaged by a piston rod 2 (see Figure 1 ) extends through the opening. The diameter of the cylindrical opening 15, i.e. the inner diameter Di of the sealing ring 14 (see Figure 3a ) is substantially equal to the diameter of the piston rod 2, or is also adjusted according to the wear in the case of wear during operation, as will be explained in more detail. The sealing ring 14 has at least three ring segments 14a, each of which has a first segment end SE1 in the circumferential direction and a second segment end SE2 in the circumferential direction. The three ring segments 14a are preferably implemented identically and can be assembled adjacent to each other in the circumferential direction to form the sealing ring 14. The advantage of dividing the sealing ring 14 into the ring segments 14a is that the sealing ring 14 can be installed on the piston rod 2 more simply and the wear of the sealing ring 14 occurring during the operation of the compressor can be better compensated. In particular, it is not necessary to disassemble the piston rod 2 in order to arrange the sealing ring 14 around the piston rod 2.

[0038] A first tangential contact surface 19a and a first axial contact surface 16 (see also Figure 3b), wherein the first axial contact surface 16 faces the first axial ring end RE1. Not only the first tangential contact surface 19a, but also the first axial contact surface 16 is preferably defined by the first wear limiting surface 22. In the example shown, the first tangential contact surface 19a and the first axial contact surface 16 directly adjoin each other and are preferably arranged at right angles to each other. In a very simple case, a first axial segment recess can be provided at the first segment end SE1 (see also Figure 3b ), the first axial segmented recess starts from the first axial ring end RE1 of the sealing ring 14 and partially extends in the direction of the second axial ring end RE2 which is axially opposite. The limiting surface of the first axial segmented recess thus constitutes the first tangential contact surface 19a and the first axial contact surface 16 and additionally constitutes the first wear limiting surface 22, the function of which will be explained in detail below.

[0039] A second tangential contact surface 19b is provided at the second segment end SE2 of the ring segment 14a, and the second tangential contact surface abuts against the first tangential contact surface 19a of the first segment end SE1 of the ring segment 14a immediately following in the circumferential direction, so as to produce a radial seal of the sealing ring 14. In addition, a second axial contact surface 17 (also see Figure 4a + Figure 4b ), the second axial contact surface abuts against the first axial contact surface 16 of the first segment end SE1 of the ring segment 14a adjacent to it in the circumferential direction to produce an axial seal of the sealing ring 14. The second tangential contact surface 19b and the second axial contact surface 17 are preferably adjacent to each other and are advantageously arranged at right angles to each other. In a very simple case, as shown, a second axial segment recess is provided at the second segment end SE2 of the ring segment 14a (see also Figure 4b ), the second axial segmented recess starts from the second axial ring end RE2 of the sealing ring 14 and extends partially in the axial direction in the direction of the opposite first axial ring end RE1. Here, the axial limiting portion of the second axial segmented recess constitutes the second axial contact surface 17, and the limiting portion in the circumferential direction constitutes the second end surface 29. However, the second axial segmented recess does not constitute the second tangential contact surface 19b, which is constituted, for example, in the following way: the ring segment 14a is tangentially divided radially outside at the second segment end SE2. However, it should be noted here that the concept of "tangential" does not necessarily refer to the tangent in the strict mathematical sense in the association with the first and second tangential contact surfaces 19a, 19b. This means that the extension direction of the tangential contact surfaces 19a, 19b does not necessarily have to constitute a tangent of a curved surface, such as the inner diameter Di or the outer diameter Da. As a result, the first and second segmented recesses can be made, for example, with the aid of a suitable milling cutter or left hollow during the injection molding process.

[0040] In the assembled state, the sealing ring 14 is arranged in the compressor such that the first axial ring end RE1 faces the crankcase in which the low pressure P N , which is substantially equal to the ambient pressure (or possibly slightly higher), and the second axial ring end RE2 faces the cylinder, in which there is a higher pressure P than that H In this regard, the concepts of high-pressure side and low-pressure side are also used below. It should be noted that when multiple sealing rings 14 are arranged one after another in the axial direction in the sealing device 1, the pressure is increased from the high pressure P on the cylinder side to the low pressure side via the entire sealing device 1. H The lower pressure P on the crankcase side N This means that the sealing ring 14 which is the first one adjacent to the cylinder in the axial direction is subjected to a higher pressure than the subsequent sealing ring 14 which faces the crankcase. In other words, the pressure conditions on the sealing rings 14 of the sealing device 1 are usually different.

[0041] In the example shown, in the newly assembled state in which the sealing ring 14 does not yet have any wear, the first and second wear limiting surfaces 21, 22 of the adjacent ring segments 14a, which face each other in the circumferential direction, are spaced apart from each other due to the wear distance a, although the tangential contact surfaces 19a, 19b and the axial contact surfaces 16, 17 still abut against each other in order to produce radial and axial sealing of the sealing ring 14. The wear distance a is used to compensate for the wear on the radially inner inner peripheral surface 18 of the sealing ring 14 during continuous operation. A circumferential groove 20 can be provided on the radially outer outer peripheral surface 23 of the sealing ring 14, which extends around the entire sealing ring 14 in the circumferential direction. The circumferential groove 20 is provided to accommodate a hose spring 11 (not shown), which tensions the sealing ring 14 in the radial direction and holds it on the piston rod 2 in the assembled state, as described according to the present invention. Figure 1 As already explained.

[0042] If wear occurs on the inner circumferential surface 18, the hose spring 11 and the high pressure P on the cylinder side will H The sealing ring 14 is combined to ensure that the sealing ring 14 is automatically adjusted radially in that the tangential contact surfaces 19a, 19b of the ring segments 14a that face each other slide relative to each other. Figure 3a As indicated by the arrows at the segment ends SE1, SE2 in FIG. 1 , the wear distance a decreases due to wear until the maximum possible wear adjustment is reached, in which case the wear distance becomes zero (a=0) and the second wear limiting surface 21 arranged at the end of the second segment end SE2 of the ring segment 14a in the circumferential direction abuts against the first wear limiting surface 22 of the first segment end SE1 of the ring segment 14a adjacent in the circumferential direction.

[0043] According to the present invention, at least three relief openings 25 are provided on at least one ring segment 14a, but preferably on all ring segments 14a, and the relief openings extend from the radially inner inner peripheral surface 18 of the corresponding ring segment 14a of the sealing ring 14 to the radially outer outer peripheral surface 23 and / or to the second axial ring end RE2 of the corresponding ring segment 14a of the sealing ring 14. The relief openings 25 are continuous recesses that connect the inner peripheral surface 18 to the radially outer outer peripheral surface 23 and / or the second axial ring end RE2. That is, the relief openings 25 do not merge into a circumferential groove on the inner peripheral surface 18 as in the prior art, but merge directly into the inner peripheral surface 18.

[0044] The relief opening 25 is used to selectively influence the pressure conditions on the sealing ring 14 during operation of the compressor between the high-pressure side of the sealing ring 14 facing the cylinder (the second axial ring end RE2) and the low-pressure side of the sealing ring 14 facing the crankcase (the first axial ring end RE1), as will be described below. Figure 5a + Figure 5b As elaborated in detail.

[0045] Each relief opening 25 has a first relief opening end 25a, which merges into the radially inner inner circumferential surface 18 of the corresponding ring segment 14a of the sealing ring 14. The relief opening ends 25a of two adjacent relief openings 25 that merge into the radially inner inner circumferential surface 18 are arranged to be spaced apart from each other in the circumferential direction at a relief opening circumferential spacing z. This means that the relief opening ends 25a are not connected to each other on the radially inner inner circumferential surface 18. As a result, the inner circumferential surface 18 of the ring segment 14a extends between two adjacent relief opening ends 25a in the circumferential direction. The relief opening circumferential spacing z is preferably 1 mm to 15 mm, particularly preferably 1-10 mm, for example 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14 mm, depending on the size of the ring segment 14a. Intermediate spacings are also feasible, such as 1.5 mm, 2.5 mm, 3.5 mm, 4.5 mm, 5.5 mm, etc. Here, the relief opening circumferential spacing z is not measured from the center of the relief opening end 25a to the center of the relief opening end 25a, but represents the spacing between the defining portions of each of the relief opening ends 25a in the circumferential direction, or in other words, the length of the inner circumferential surface 18 between adjacent relief opening ends 25a in the circumferential direction. However, the relief opening circumferential spacing z between the relief opening ends 25a of each relief opening 25 of a ring segment 14a does not have to be mandatory to be equal.

[0046] The relief opening end 25a is arranged at a distance from the first axial ring end RE1 by a relief opening axial spacing x. Thus, in the axial direction, the inner circumference 18 of the ring segment 14a extends between the relief opening end 25a and the first axial ring end RE1. The relief opening axial spacing x is 4% to 20% of the axial ring width RB, particularly preferably 4-15%, in particular a maximum of 10%, such as in Figure 2 Neutralization details in Figure 6 As shown in . The axial spacing x of the relief openings is also not measured from the center of the relief opening end 25a, but is measured from the limiting portion of the relief opening end 25a, or in other words, as the length of the inner circumference 18 in the axial direction between the relief opening end 25a and the first axial ring end RE1. However, the radial spacing x of the relief openings of the individual relief opening ends 25a of the relief openings 25 of a ring segment 14a does not necessarily have to be equal. Here, the axial ring width RB extends between the first and second axial ring ends RE1, RE2. The details of the structural scheme of the relief opening 25 will be described below according to Figure 6 Elaborate. Figure 2 As can be seen in the figure, the axial relief opening width of the relief opening 25 is smaller than the ring width RB at least at the relief opening end 25a. In the case where the relief opening 25 (at least at the relief opening end 25a) is a circular cross section, the axial relief opening width is equal to the diameter. The axial relief opening width of the relief opening end 25a is preferably 2%-30% of the ring width RB, preferably 2-25%, particularly preferably a maximum of 20%, especially a maximum of 15%. Usually, the relief opening end 25a is not centered between the two axial ring ends RE1, RE2 of the sealing ring 14, but is closer to the first axial ring end RE1 than the second axial ring end RE2. The first axial ring end RE1 faces the low-pressure side in the assembled state.

[0047] In the drawings, especially Figures 2 to 4b The further features shown in the drawing, in particular the extension of the relief opening 25, the arrangement of one or more wear openings 27, the circumferential groove 20 or the axial groove 24 are optional and will be described below. Figure 2 The embodiment of the sealing ring 14 shows an advantageous embodiment having a plurality of features which are independent of one another.

[0048] In order to improve the structural rigidity of the sealing ring 14, at least one axial groove 24 can be provided on the outer peripheral surface 23 of at least one ring segment 14a, preferably each ring segment 14a, and the axial groove extends continuously in the axial direction from the first axial ring end RE1 (possibly interrupted by the circumferential groove 20) to the second axial ring end. However, it is preferred that each ring segment 14a is provided with a plurality of axial grooves 24. In the example shown, each relief opening 25 merges into an axial groove 24 on the outer peripheral surface 23. However, this is of course not mandatory, and the relief opening 25 may also merge into the outer peripheral surface 23 of the sealing ring 14 (or merge into the circumferential groove 20) in the circumferential direction in addition to the axial groove 24.

[0049] The relief openings 25 in the embodiment shown are each designed as cylindrical holes, since they can be produced particularly easily by cutting. However, it is of course also possible to provide one or more relief openings with a non-circular cross section and / or a non-straight extension of the relief openings 25, which would however increase the effort required to produce the relief openings 25.

[0050] The relief opening 25 preferably has a straight extension so that it can be produced as simply as possible, for example by means of a cylindrical drill or milling cutter. However, other production methods are of course also conceivable, for example the relief opening 25 can be produced directly by means of an injection molding process, in particular integrated into the ring segment 14a during the injection molding process, without, for example, subsequent drilling being required. It is also conceivable to produce the sealing ring 14 by means of an additive manufacturing process, for example 3D printing, in which case the relief opening 25 can again be taken into account directly during production.

[0051] However, how the relief openings 25 are manufactured is not important for the present invention. What is important is that the boundary conditions required for the relief openings 25, namely the circumferential spacing z of the relief openings in the circumferential direction, the axial spacing x of the relief openings and the requirement that the relief openings 25 extend from the radially inner inner peripheral surface 18 to the radially outer outer peripheral surface and / or to the second axial ring end RE2 (where the cylinder-side high pressure P is respectively present) are observed. H In a very simple construction, the relief opening 25 extends in the radial direction of the sealing ring 14, such as Figure 6 As shown in the sectional view AA of , ie, extending parallel to the axial ring ends RE1 , RE2 .

[0052] However, according to a preferred embodiment, at least one section of the radially inner inner circumferential surface 18 of the at least one relief opening 25 adjacent to the sealing ring 14 is inclined in the direction of the first axial ring end RE1, for example at a first relief opening angle ε, such as Figure 2As shown in the examples shown in Figure 6 As explained in detail. As a result, the pressure conditions on the sealing ring 14 can be influenced in a targeted manner during the service life of the sealing ring 14, so that the pressure compensation of the sealing ring 14 can be matched to the radial wear. In the simplest case, the corresponding relief opening 25 is also implemented as a cylindrical hole in this construction scheme, wherein the hole axis is inclined toward the first axial ring end RE1. As a result, the second relief opening end 25b that opens into the radially outer outer peripheral surface 23 is closer to the first axial ring end RE1 than the first relief opening end 25a of the relief opening 25 that opens into the radially inner inner peripheral surface 18. Due to the inclined extension direction, the first relief opening end 25a basically "moves" in the direction of the first axial ring end RE1 in the case of radial wear of the ring segment 14a, whereby the pressure compensation of the sealing ring 14 is increased according to the wear, because the high pressure P on the inner peripheral surface 18 is increased. H In the axial direction, it is closer to the first axial ring end RE1. This basically means that the higher the wear of the ring segment 14a, the higher the pressure compensation. This reduces the radial pressure of the sealing ring 14 on the piston rod 2 during operation and increases the service life of the sealing ring 14.

[0053] In order to better distribute the pressure on the radially inner inner circumferential surface 18 in the circumferential direction, one or more relief openings 25 may also end in the radially inner inner circumferential surface 18, for example, in the form of a milled hole / groove, which extends in a relatively small area in the circumferential direction. In this case, the first relief opening end 25a may no longer have the preferably circular cross-section of the remaining relief openings 25 (which are radially located between the milled hole / groove and the outer outer circumferential surface 23 and / or the second axial ring end RE2), but may be formed by a corresponding shape of the milled hole / groove. The circumferential spacing z of the relief openings in the circumferential direction and the axial spacing x of the relief openings in the axial direction may then be measured in the axial direction and in the circumferential direction starting from the corresponding limiting portions of the milled hole / groove. For example, a slotted hole may also be provided instead of the milled hole / groove. Typically, the relief opening 25 has a relief opening length in the circumferential direction at least at its relief opening end 25a, which is preferably 2-100%, preferably 2-50%, and in particular a maximum of 25% of the axial ring width RB of the sealing ring 14. Generally, it is important that the relief opening ends 25a are not connected to each other on the radially inner inner peripheral surface 18 by circumferential grooves provided for pressure compensation during operation. Because circumferential grooves, especially in combination with a small axial spacing x between the relief openings, can lead to a narrow side surface formed by the ring material at the first axial ring end RE1. During operation, this side surface can induce vibrations, which can lead to uneven wear and undesirable non-sealing locations.

[0054] According to another advantageous embodiment of the invention, at least one wear opening 27 is additionally provided on at least one ring segment 14a of the sealing ring 14, preferably on each ring segment 14a, which extends from the radially outer peripheral surface 23 and / or the second axial ring end RE2 of the sealing ring 14 via a portion of the ring height RH in the direction of the radially inner inner peripheral surface 18 of the sealing ring 14, but does not extend to the inner peripheral surface 18 of the ring segment 14a in the unworn state. In the case of a hole, the wear opening 27 may be implemented, for example, as a blind hole starting from the outer peripheral surface 23 in the direction of the inner peripheral surface 18. Of course, as an alternative or in addition, the wear opening 27 implemented as a hole may also be drilled from the second axial ring end RE2 in the direction of the inner peripheral surface 18. For the wear opening 27, it is important that (irrespective of its embodiment) the wear opening end 27a (see FIG. 2 ) of the at least one wear opening 27 which faces the inner peripheral surface 18 at the farthest distance in the radial direction. Figure 6 ) is spaced apart from the radially inner inner circumference 18 of the ring segment 14a in the radial direction of the ring segment 14a by a distance of at most 40%, preferably at most 30%, and particularly preferably at most 20% of the ring height RH. Here, the ring height RH extends between the outer circumference 23 of the sealing ring 14 and the radially inner inner circumference 18, i.e., is substantially equal to half the difference between the inner diameter Di and the outer diameter Da of the sealing ring 14, as shown in FIG. Figure 4a As shown in FIG. It is important that the wear opening end 27a is between the first and second axial ring ends RE1, RE2 and is spaced apart from the first and second axial ring ends RE1, RE2. This means that the wear opening end 27a is surrounded by the ring material not only in the axial direction but also in the circumferential direction, so that it is exposed only in the case of corresponding radial wear.

[0055] But preferably, as in Figure 2 4, a plurality of wear openings 27 are provided along the circumference of the ring segment 14, particularly preferably at least two wear openings 27 are provided per ring segment 14a. In the example shown, the wear openings 27 extend from the outer circumferential surface 23, or here from the outer circumferential groove 20 provided on the outer circumferential surface 23, in the radial direction of the sealing ring 14 (parallel to the axial ring ends RE1, RE2) toward the inner circumferential surface 18 without reaching the inner circumferential surface 18, and are implemented as cylindrical holes.

[0056] If the wear openings 27 are drilled, they can have a conical bottom, as shown, corresponding to the drill used. If the wear openings 27 are milled, for example, by means of a milling cutter, they usually have a substantially flat base. However, other manufacturing possibilities are of course also conceivable, such as injection molding or additive manufacturing.

[0057] The length and diameter of the wear opening 27 depend essentially on the desired pressure compensation properties of the sealing ring 14, wherein the length or extension in the radial direction is designed such that the wear opening end 27a of the wear opening 27 is spaced apart from the inner circumference 18 by a distance of no more than 40% of the radial ring height RH of the sealing ring 14. Figure 2 In the example shown in FIG. 4 , the wear openings 27 are arranged centrally in the axial direction between the two ring ends RE1, RE2. However, they may also be arranged closer to the ring ends RE1, RE2, preferably at a wear opening axial spacing y from the first axial ring end RE1, which is 2% to 20%, preferably 2-15%, in particular a maximum of 10% of the ring width RB, as described in accordance with Figure 6 As will be explained in more detail below, the specific axial arrangement depends essentially on the desired pressure compensation of the sealing ring 14 .

[0058] The at least one wear opening 27 of the ring segment 14a, or the preferably multiple wear openings 27, is designed so that starting from a certain wear state of the sealing ring 14, the wear opening end 27a (see Figure 2 and especially Figure 6 ) is exposed. Thus, starting from this worn state, the wear opening 27 extends completely from the outer circumferential surface 23 to the inner circumferential surface 18. Starting from this worn state, the wear opening 27 thus acts like a relief opening 25. In particular, the wear opening 27 subsequently increases the pressure compensation between the inner circumferential surface 18 and the outer circumferential surface 23 of the sealing ring 14 during operation of the compressor, thereby, for example, being able to avoid premature, undesirable collapse of the sealing ring 14.

[0059] However, the wear opening 27 can also extend similarly to the relief opening 25 from the second axial ring end RE2 in the direction of the inner circumference 18, because the high pressure P H .

[0060] For example, the size of the wear opening 27 can be determined in such a way that, starting from the wear state in which the wear opening 27 is exposed on the inner circumference 18, a substantially complete pressure compensation is achieved between the inner circumference 18 and the outer circumference 23. As a result, the sealing ring 14 may partially lose its sealing effect, but the risk of damage can be reduced, especially avoided. Complete pressure compensation is understood here to mean that the radial forces acting on the outer circumference 23 and on the inner circumference 18 caused by the pressure are substantially completely compensated, so that in the radial direction, there is basically no force caused by the pressure difference acting on the sealing ring 14. This basically means that the sealing ring 14 will fail automatically starting from a certain wear state. For this purpose, it is preferably provided that one or more other sealing rings 14 of the sealing device 1 that may have less wear still basically normally exert their sealing effect. As a result, the failed sealing ring 14 does not have to be replaced immediately, which may lead to the compressor being shut down, but it is easier to comply with the predetermined maintenance interval, for example, starting from a certain leakage amount that can be detected using measurement technology.

[0061] Similar to the relief opening 25, it may be advantageous if at least one end section of at least one wear opening 27 facing the radially inner inner circumferential surface 18 is inclined in the direction of the first axial ring end RE1, for example by a wear opening angle φ, as will be described below according to Figure 6 As explained in more detail. Thus, in this case, the pressure compensation characteristic can also be adjusted via wear. Preferably, each wear opening 27 is arranged in the circumferential direction between two relief openings 25, particularly preferably centrally between the two relief openings 25.

[0062] exist Figure 3a In the figure, a plan view orthogonal to the first axial ring end RE1 or preferably to the flat first ring end surface is shown. Figure 2 In the sealing ring 14 shown in FIG. 1 , the first ring end surface faces the low-pressure side in the assembled state. Figure 3b Show according to Figure 3a The single ring segment 14a of the sealing ring 14. Figure 3bThe shape of the first axial segment recess can be seen in FIG. 1 , which is arranged on the first segment end SE1 of the ring segment 14a to form the first tangential contact surface 19a and the first axial contact surface 16. As already described, the first axial segment recess 16 extends partially in the axial direction from the first axial ring end RE1 in the direction of the opposite second axial ring end RE2, so that the second segment end SE2 of the ring segment 14a immediately following in the circumferential direction can be embedded in the first axial segment recess. In other words, the adjacent ring segments 14a partially overlap in the circumferential direction, so that the first tangential contact surface 19a of the first segment end SE1 of the ring segment 14a is in contact with the second tangential contact surface 19b of the second segment end SE1 of the adjacent ring segment 14a, so as to produce a radial seal of the sealing ring 14. Similarly, the first axial contact surface 16 of the first segment end SE1 of the ring segment 14a formed by the corresponding first axial segment recess is in contact with the second axial contact surface 17 of the second segment end SE2 formed by the corresponding second axial segment recess, so as to produce an axial seal of the sealing ring 14. The first axial segment recess and the second axial segment recess are arranged on the segment ends SE1, SE2 of the ring segment 14a that are opposite in the circumferential direction and on the opposite axial ring ends RE1, RE2.

[0063] Here, the segment ends SE1, SE2 act together in the circumferential direction so that the tangential contact surfaces 19a, 19b face each other and can slide against each other. This allows the wear adjustment of the sealing ring 14 to be achieved during operation until the wear distance a (see Figure 2 + Figure 3a ) The second wear limiting surface 21 of the second segment end SE2 of the ring segment 14a is in contact with the first wear limiting surface 22 of the first axial segment recess of the first segment end SE1 of the adjacent ring segment 14a. On the second segment end SE2 of the ring segment 14a, an outer chamfer R2 with a specific radius is preferably provided at the transition between the second tangential contact surface 19b and the second wear limiting surface 21 to facilitate wear adjustment or, in particular, mutual sliding of the tangential contact surfaces 19a and 19b. Advantageously, an inner chamfer R1 is similarly provided between the first tangential contact surface 19a and the first wear limiting surface 22 at the first segment end SE, such as at Figure 3b and Figure 4b As shown in .

[0064] The wear openings 27 are designed here as blind holes with a conical bottom and extend from the outer circumferential surface 23, here from the bottom of the circumferential groove 20, radially over a partial ring height RH in the direction of the inner circumferential surface 18, wherein the wear opening ends 27a of the wear openings 27 are each spaced apart in the radial direction of the sealing ring 14a from the radially inner inner circumferential surface 18 by a distance which is at most 40% of the radial ring height RH of the sealing ring 14. In the sealing ring 14 shown, three relief openings 25 and two wear openings 27 are provided per ring segment 14a. The wear openings 27 are arranged here centrally between the relief openings 25 in the circumferential direction. The wear openings 27 extend here in the radial direction of the sealing ring 14 (parallel to the axial ring ends RE1, RE2), while the relief openings 25 are designed obliquely, i.e. in the direction of the first axial ring end RE1, in order to increase the pressure compensation depending on the wear situation. However, this construction scheme is of course to be understood only as an example, and the exact structural design, as well as the number and orientation of the relief openings 25 and / or wear openings 27 are of course determined by those skilled in the art and depend on the desired field of application of the sealing ring 14 and the effects to be achieved, in particular the pressure compensation to be achieved.

[0065] Figure 4a and Figure 4b The sealing ring 14 or an individual ring segment 14a of the sealing ring 14 is shown in a top view of the second axial ring end RE2 which, in the installed state, faces the high-pressure side of the compressor. Figure 4b A second axial segment recess can be seen, which is arranged on the second segment end SE2 of the ring segment 14a to form a second axial contact surface 17. The second tangential contact surface 19b is arranged outside the second segment end SE2 in the radial direction. The second axial segment recess extends partially from the second axial ring end RE2, in particular from a preferably flat second ring end surface 28 arranged thereon, in the axial direction in the direction of the first axial ring end RE1, in particular the flat first ring end surface. In addition to the second axial contact surface 17, the second axial segment recess further forms a second end surface 29 of the second segment end SE2, which is spaced apart from the first end surface 30 of the first segment end SE1 of the adjacent ring segment 14a by a segment spacing b, as shown in Figure 4a Thus, the adjacent segment ends SE1, SE2 cooperate to form a radial recess 31 which completely penetrates the sealing ring 14 in the radial direction and is limited in the axial direction, and whose width is equal to the segment spacing b. In the case of continuous wear of the sealing ring 14, the segment spacing b is reduced to the same width as the wear spacing a (see Figure 2 + Figure 3a) is reduced in a similar manner over a certain period of time until the wear distance a becomes zero (where b>a). In the case of equal dimensions a=b in the unworn (new) state of the sealing ring 14, the wear distance a in the example shown becomes zero earlier than the segment distance b due to continued wear for kinematic reasons. This is mainly related to the specific structural design, in particular to the arrangement of the tangential contact surfaces 19a, 19b. However, as an alternative, the end surfaces 29, 30 may also be used as wear limiting parts (where a>b).

[0066] However, the tangential contact surfaces 19a, 19b may also extend continuously from the outer peripheral surface 23 to the inner peripheral surface 18, for example. As a result, the wear adjustment may no longer be limited by the wear spacing a, as has been shown so far. Therefore, the first axial segment recess provided on the first segment end SE1 may no longer have the first wear limiting surface 22, and the second segment end SE2 may no longer have the second wear limiting surface 21. In this case, the wear adjustment may be limited, for example, by a radial recess 31 at the second axial ring end RE2, the width of which is equal to the segment spacing b, as has been described according to Figure 4a As shown.

[0067] Of course, the material and surface properties of the sealing ring 14 can also be varied in order to achieve the best possible results in the application. According to an advantageous embodiment, the sealing ring 14 is made of a suitable, tribo-optimized material, for example a polytetrafluoroethylene (PTFE) composite material. The production can be carried out, for example, by machining, by injection molding, or alternatively by additive manufacturing processes, for example 3D printing.

[0068] exist Figure 5a The following diagram schematically shows in simplified form the operation of the compressor with a conventional sealing ring 7b (see Figure 1 ) on the pressure. In contrast, Figure 5b The pressure conditions on the sealing ring 14 according to the present invention are shown in FIG. The sealing ring 14 is preferably arranged in a sealing device 1 (not shown), which is arranged, for example, in the crankcase of a compressor to seal the piston rod 2 (for example Figure 1 ). The sealing rings 7b, 14 are arranged such that the respective first axial ring end RE1 faces the low-pressure side (crankcase side) and the respective second axial ring end RE2 faces the high-pressure side (cylinder side). The sealing rings 7b, 14 are arranged such that the respective first axial ring end RE1 abuts against the housing segment 3i of the sealing device 1, so that a seal is produced in the radial direction between the first axial ring end RE1 and the housing segment 3i. This seal corresponds to a substantially static seal, since there is no relative movement or only a very small relative movement between the first axial ring end RE1 of the sealing ring 14 and the housing segment 3i.

[0069] In this case, a high pressure P is present on the radially outer peripheral surface 23. H , and on the radially inner inner peripheral surface 18 at the first axial ring end RE1 there is a pressure P lower than the high pressure. N . High pressure P H In the radial direction it decreases to a low pressure P N , wherein the pressure curve in the example has a nonlinear extension. At the second axial ring end RE2 there is a high pressure P N The radial ring height RH is substantially constant between the radially outer peripheral surface 23 and the radially inner inner peripheral surface 18. It should be noted that the pressure on the sealing device 1 increases in the axial direction from the high pressure P in the cylinder to the pressure on the sealing device 1. H The low pressure P in the crankcase is gradually reduced via a correspondingly provided number of sealing rings 14. N This means that the pressure conditions on the individual sealing rings 14 of the sealing device 1 are usually different. Therefore, the high pressure P H is not equal to the high pressure P present on the subsequent sealing ring 14 H That is to say, the high pressure P in this specification H and low pressure P N Each relates to a sealing ring 14. The low pressure P on a sealing ring 14 N is approximately equal to the high pressure P of the sealing ring 14 following it in the corresponding axial direction (towards the crankcase) H etc.

[0070] Similarly, a high pressure P is present on the radially outer peripheral surface 23. H , wherein the pressure is substantially constant between the second axial ring end RE2 and the first axial ring end RE1 over the axial ring width RB of the sealing ring 14. The high pressure P at the second axial ring end RE2 (cylinder side) is realized on the radially inner inner circumferential surface 18 which bears against the translatory reciprocating piston rod 2 during operation. H and a pressure P at the first axial ring end RE1 (crankcase side) which is lower than the high pressure. N This is a dynamic seal based on the relative movement between the (stationary) sealing ring 14 and the translatory reciprocating piston rod 2. Figure 5a As shown in FIG. 1 , the inner circumferential surface 18 located radially inwardly generally obtains a substantially linear pressure curve, wherein the pressure increases from the high pressure P (at the second axial ring end RE2) to the high pressure P (at the second axial ring end RE2). H Reduced to the low pressure P (at the first axial ring end RE1) NAlthough in principle the pressure drop in the axial direction on the inner circumference 18 is also nonlinear due to the compressibility of the gaseous medium, in certain cases (e.g. at high absolute pressures, the high pressure P H and low pressure P N For simplicity, the pressure curve can be well approximated by a linear function, as shown. Figure 5a In the example shown in FIG. 1 , this means that the sealing ring 7 b is pressed radially more strongly onto the piston rod 2 due to the greater radial pressure difference compared to the sealing ring 14 according to the invention, which leads to higher wear and is therefore disadvantageous. In addition, due to the greater radial pressure difference compared to the second axial ring end RE2, Figure 5a The sealing ring 7b is pressed more strongly against the piston rod 2 in the region of the first axial ring end RE1 than at the second axial ring end RE2. Such an uneven pressure distribution can additionally lead to uneven wear under certain circumstances, which is likewise disadvantageous.

[0071] Figure 5b 1 shows a sealing ring 14 according to the invention, wherein the sectional view extends in the region of the relief openings 25, which are designed here as cylindrical holes and extend in the radial direction of the sealing ring 14 parallel to the axial ring ends RE1, RE2. However, as already mentioned, each ring segment 14a is provided with at least three relief openings 25 in order to form the pressure curve as uniform as possible in the circumferential direction. The pressure curve at the axial ring ends RE1, RE2 and on the radially outer outer peripheral surface 23 is substantially the same as that according to Figure 5a At this time, the pressure curve on the dynamic sealing surface of the inner circumference 18 located radially inward between the piston rod 2 and the sealing ring 14 is specifically influenced by the at least three relief openings 25 of each ring segment 14a.

[0072] As in Figure 5b As can be seen in the figure, the outer peripheral surface 23 (high pressure P H ) and the inner circumferential surface 18 (low pressure P N ). This means that the pressure between the second axial ring end RE2 (cylinder side) and the delimitation of the first unloading opening end 25a of the unloading opening 25 toward the first axial ring end RE1 is substantially constant. Starting from the delimitation of the first unloading opening end 25a of the unloading opening 25 toward the first axial ring end RE1 and the first axial ring end RE1, the pressure is increased from the high pressure P H Reduce to a pressure P lower than the high pressure N , where the pressure curve is approximately linear, as shown in Figure 5aAs described.

[0073] Different from Figure 5a The sealing ring 7b, according to Figure 5b On the sealing ring 14, substantially complete pressure compensation is achieved in the region between the second axial ring end RE2 and the first relief opening end 25a of the relief opening 25 which is defined in the axial direction towards the first axial ring end RE1. Figure 5a The pressure curve and Figure 5b The pressure difference ΔP between the pressure curves in Figure 5b It can be seen from this that the sealing ring 14 is supported in a longer area in the axial direction due to radial pressure compensation compared to the conventional sealing ring 7b, and is still pressed more strongly onto the piston rod 2 only in the area between the defining portion of the first relief opening end 25a facing the first axial ring end RE1 and the first axial ring end RE1 due to the radial pressure difference.

[0074] In practice, the maximum possible pressure compensation is limited by the relief opening circumferential spacing z between the relief openings 25, the relief opening axial spacing x between the relief opening ends 25a and the first axial ring end RE1, and by the material properties of the sealing ring 14. The structural design is realized in such a way that the relief opening circumferential spacing z between the relief openings 25 in the circumferential direction and the relief opening axial spacing x between the relief openings 25 and the first axial ring end RE1 in the axial direction are selected so that a sufficiently high strength of the sealing ring 14 is ensured under the given material, so that deformation and the resulting leakage in the area between the first relief opening end 25a and the first axial ring end RE1 of the sealing ring 14 do not occur as much as possible.

[0075] To ensure this, the circumferential spacing z of the relief openings is 1 mm to 15 mm, the axial spacing x of the relief openings is 4% to 20% of the axial ring width RB, the relief opening length of the relief opening 25 (at least at the relief opening end 25a) is preferably 2% to 100% of the ring width RB, and the axial relief opening width of the relief opening 25 (at least at the relief opening end 25a) is preferably 2%-30% of the axial ring width RB. Here, the axial relief opening width of the relief opening end 25a and the axial spacing x of the relief openings are coordinated with each other so that at least the following condition is met, that is, the relief opening end 25a is not centered between the axial ring ends RE1, RE2, that is, it is closer to the first axial ring end RE1 than the second axial ring end RE2. If the circumferential spacing z of the relief openings is too small, the ring may be excessively weakened, which may lead to undesirable deformation and higher leakage. On the contrary, if the circumferential spacing z of the relief openings is too large, in some cases, the high pressure P cannot be completely formed between the relief opening ends 25. HThis can lead to an unfavorable pressure distribution in the circumferential direction and thus to insufficient pressure compensation, which in turn can lead to higher friction and thus to higher ring wear. Figure 5b The size, shape and arrangement of the relief openings 25 shown in FIG. 2 are to be understood as examples only, and the specific structural design depends on the application field of the sealing ring 14 and is determined by a person skilled in the art.

[0076] exist Figure 6 Different possibilities for arranging the relief opening 25 and the wear opening 27 are shown by way of example on the basis of a plurality of longitudinal sectional views AA to DD of the sealing ring 14. In the sectional view AA a relief opening 25 is shown which extends in the radial direction of the sealing ring 14, i.e. essentially parallel to the two axial ring ends RE1, RE2. The relief opening 25 has a circular cross-section and is spaced apart from the first axial ring end RE1 by an axial relief opening spacing x, which is measured from a defining portion of a first relief opening end 25a of the relief opening 25, which faces the first axial ring end RE1. The axial relief opening spacing x depends on the field of application of the sealing ring 14 and in particular on the desired pressure curve on the radially inner inner peripheral surface 18 of the sealing ring, as has been described according to Figure 5b As shown. The axial spacing x of the relief openings is 4% to 20%, preferably 4-15%, and particularly preferably 4-10% of the axial ring width RB of the sealing ring 14. As already mentioned, the axial spacing x of the relief openings should not fall below a certain minimum spacing to ensure a sufficiently high strength of the sealing ring 14, wherein the minimum spacing is 4% of the axial ring width RB. That is, if the relief holes 25 are implemented as continuous radially extending holes as shown, they are preferably mainly arranged on the half of the sealing ring 14 facing the low-pressure side.

[0077] If the relief opening 25 is designed as a cylindrical hole, the relief opening diameter d E Preferably, it is between 2-30%, preferably 2-25%, particularly preferably 2-20%, and in particular a maximum of 15% of the axial ring width RB of the sealing ring 14. However, the relief opening 25 can also have a non-circular cross section, for example an elliptical cross section or a cross section in the form of an elongated hole. In this case, the dimension refers to the axial opening width of the relief opening 25.

[0078] Regardless of the cross-sectional shape and extension of the relief opening 25, it is generally applicable that the first relief opening end 25a of the relief opening 25 is eccentrically arranged on the radially inner inner peripheral surface 18. In other words, it is closer to the first axial ring end RE1 in the axial direction than the second axial ring end RE2. As a result, the axial relief opening width of the relief opening 25 at the first relief opening end 25, for example, the diameter in the case of a circular cross section, is related to the relief opening axial spacing x. This means that the larger the relief opening axial spacing x from the first ring end RE1, the smaller the maximum possible axial relief opening width is, in order to ensure that the relief opening end 25a is closer to the first axial ring end RE1 in the axial direction than the second axial ring end RE2.

[0079] However, as already mentioned and according to Figure 2 As shown, the relief opening 25 may also have an extension that deviates from the radial direction of the sealing ring 14, as in Figure 6 As shown in the sectional view DD in . The relief opening 25 here has a circular cross-section similar to the sectional view AA, but the relief opening 25 is arranged obliquely in the axial direction with respect to the radial direction at a relief opening angle ε. As a result, the radially outer second relief opening end 25b of the relief opening is closer to the first axial ring end RE1 than the radially inner first relief opening end 25a. In the example shown, the relief opening angle ε is measured between the first axial ring end RE1 and the axis of the relief opening 25 implemented as a cylindrical hole. The relief opening axial spacing x is measured from the limiting portion of the first relief opening end 25a on the radially inner inner inner peripheral surface 18 as described, and the first relief opening end faces the first axial ring end RE1. Of course, the value of the relief opening axial spacing x is for the brand new state of the sealing ring 14 without wear. However, in the top view (Figure 3+Figure 4), the relief opening 25 can also have an extension direction that deviates from the radial direction, that is, as will be described below according to Figure 8b More details as described in the tilt.

[0080] By arranging at least one relief opening 25 at an angle, the pressure compensation can be varied depending on the wear of the sealing ring 14, since the axial position of the radially inner relief opening end 25 changes as a function of the wear. In the example shown, the relief opening end 25 moves in the direction of the first axial ring end RE1 in the case of radial wear v of the sealing ring 14. This means that the axial spacing x of the relief openings is v In the case of radial wear v, it is smaller than the axial spacing x of the relief openings in the new state of the sealing ring 14. Of course, the axial spacing x of the relief openings vThe size of depends on the relief opening angle ε. As a result, the pressure compensation in the axial direction is increased depending on the wear state of the sealing ring 14, wherein the degree of pressure compensation can be selected depending on the size of the relief opening angle ε.

[0081] However, the relief opening 25 does not have to be designed completely inclined over its entire length. In principle, it may also be sufficient if only the section of the relief opening 25 adjoining the inner circumference 18 is inclined in the direction of the first axial ring end RE1. The remaining section of the relief opening 25 facing the outer circumference 23 may extend parallel to the ring ends RE1, RE2, as indicated by dashed lines in the sectional view DD. As a result, the pressure compensation of the partially inclined relief opening 25 may be associated with wear for a certain period of time (the first relief opening end 25a moves in the direction of the first ring end RE1), until wear v is reached and the inclined section of the relief opening 25 disappears substantially completely.

[0082] In the case of further increased wear, the pressure compensation may remain essentially constant based on the straight (dashed) section of the relief opening 25, because the first relief opening end 25a will not move further in the direction of the first axial ring end RE1. Here, the length of the inclined section of the relief opening 25 in the radial direction of the sealing ring 14 is preferably between 0-60% of the ring height RH, particularly preferably 40%. Of course, the entire relief opening 25 or the section of the relief opening 25 adjacent to the inner circumference 18 may also have a completely or partially curved extension instead of a straight extension. In this case, the relief opening 25 or the section of the relief opening 25 adjacent to the inner circumference 18 may be bent in the direction of the first axial ring end RE1, so that the first relief opening end 25a moves in the direction of the first ring end RE1 as a function of wear.

[0083] According to a further advantageous embodiment of the invention, as already mentioned, one or more wear openings 27 can be provided on the sealing ring 14 in addition to the relief opening 25, as already described. Figure 2 The sectional view BB shows a cylindrical hole with a conical bottom and a wear opening diameter d vThe wear opening 27 is a wear opening 27. Here, the wear opening 27 extends in the radial direction of the sealing ring 24, in the example shown, that is, parallel to the first and second axial ring ends RE1, RE2. However, unlike the relief opening 25, the wear opening 27 starts from the radially outer outer peripheral surface 23 of the sealing ring 14 and extends only over a portion of the ring height RH in the direction of the radially inner inner peripheral surface 18 without reaching this inner peripheral surface (in a new state, without wear). This means that, starting from a certain radial wear v of the sealing ring, the wear opening 27 connects the radially outer outer peripheral surface 23 of the sealing ring 14 with the radially inner inner peripheral surface 18. As a result, the wear opening 27 only contributes to pressure compensation starting from this wear state v and only then begins to basically assume a function similar to that of the relief opening 25.

[0084] The at least one wear opening 27 is spaced apart from the first axial ring end RE1 by a wear opening axial spacing y, wherein the wear opening axial spacing y is measured from the point of the wear opening 27 which is closest to the inner peripheral surface 18 in the axial direction, since this point is exposed first due to wear. This means that the wear opening 27 is not connected to the first axial ring end RE1, but is only connected to the radially outer peripheral surface 23 and / or to the second axial ring end RE2. Typically, the radially inner wear opening end 27a facing the inner peripheral surface 18 is thus located between the first and second axial ring ends RE1, RE2. The wear opening end 27a is therefore surrounded by the material of the sealing ring 14 as seen in the axial direction and in the circumferential direction. In the example shown (sectional view BB), the wear opening 27 is implemented as a hole with a conical bottom, whereby the wear opening axial spacing y is measured up to the apex of the wear opening end 27a. The wear opening axial spacing y can be as large as the relief opening axial spacing x, but can also be different, for example, as in Figure 6 The axial distance y of the wear openings is preferably between 2 and 20%, particularly preferably between 2 and 15%, and in particular a maximum of 10%, of the axial ring width RB of the sealing ring 14 .

[0085] The radial extension of the wear opening 27 from the radially outer circumferential surface 23, in this case the wear opening depth t of the cylindrical hole, is v The wear opening end 27a is selected so that it is spaced apart from the inner circumference 18 in the radial direction by a distance which is at most 40% of the radial ring height RH and is advantageously selected according to the expected wear v of the sealing ring. For example, it is possible to determine in an experiment how long it takes for a specific sealing ring material to reach a specific wear v under specific operating conditions and taking into account the surface roughness of the piston rod 2. From this, it is possible to estimate, for example, how long the compressor can be operated (for example, how many hours) until the wear v is reached. The wear opening depth t of the wear opening 27 is thenv It is possible to measure in such a way that wear opening 27 connects radially outer outer circumferential surface 23 to radially inner inner circumferential surface 18 starting from a certain number of operating hours, in order to be able to achieve a higher pressure compensation starting from this time.

[0086] However, it is also possible to provide at least one wear opening 27 on the sealing ring 14, at which at least one end section of the radially inner inner circumferential surface 18 is inclined in the direction of the first axial ring end RE1. However, it is preferred that not only the end section of the wear opening 27 is inclined (as indicated by the dashed line in the sectional view CC), but also the entire wear opening 27 is inclined. In particular, the at least one wear opening 27 can be implemented as a cylindrical hole, which extends from the radially outer outer circumferential surface 23 in an inclined manner in the direction of the radially inner inner circumferential surface 18, as in Figure 6 The wear opening 27 is here inclined at a wear opening angle φ relative to the first axial ring end RE1. As a result, a higher pressure compensation can be achieved starting from the wear v, similar to the straight embodiment (sectional view BB). In addition, in the case of the inclined variant according to the sectional view CC, starting from the wear v, the pressure compensation can be automatically increased as a result of further increasing wear, as has been explained with respect to the relief opening 25. The wear opening depth t v In the case of an inclined hole, it is not equal to the hole depth, but rather to the maximum extension of the wear opening 27 in the radial direction starting from the radially outer circumferential surface 23 , as shown in the sectional view CC.

[0087] The wear opening diameter d of the wear opening 27 (in the case of a circular cross section) is v For example, it can be equal to the unloading opening diameter v E Likewise, the wear opening angle φ between the wear opening 27 and the first axial ring end RE1 may be equal to the relief opening angle ε or may be different therefrom. This in turn depends on the boundary conditions under which the sealing ring 14 is used and the desired properties in terms of the pressure compensation to be achieved.

[0088] However, the relief opening 25 and / or the wear opening 27 do not necessarily have to open into the radially outer peripheral surface 23 of the sealing ring 24. For example, it is conceivable that, as an alternative or in addition, the relief opening 25 and / or the wear opening 27 extend into the second axial ring end RE2, as indicated by dashed lines in the sectional view AA with respect to the relief opening 25 and in the sectional view BB with respect to the wear opening. HAlso present at the second axial ring end RE, the effect of pressure compensation can therefore also be achieved by means of a relief opening 25, which connects the radially inner inner circumference 18 to the second axial ring end RE2 or by means of a wear opening 27, which connects the inner circumference 18 to the second axial ring end RE2 starting from a certain wear v. However, it is advantageous for simpler production if the relief opening 25 and / or the wear opening is arranged, in particular in the form of a cylindrical hole, from the radially outer outer circumference 23 of the sealing ring 24 to the radially inner inner circumference 18 or in the direction of the radially inner inner circumference.

[0089] According to a further advantageous embodiment of the sealing ring 14, at least one compensating recess 32 can be provided on the sealing ring 14, such as in Figures 7a to 7d As shown in the respective ring segments 14a in FIG. 1 . The at least one compensating recess 32 extends from the radially outer outer circumferential surface 23 of the sealing ring 14 over a portion of the ring height RH in the direction of the radially inner inner circumferential surface 18 of the sealing ring 14, and extends from the first axial ring end RE1 over a portion of the ring height RB in the direction of the second axial ring end RE2. The compensating recess 32 is basically used to reduce the axial pressing force and thus reduce the pressure between the first axial ring end RE1 and the housing segment 3i of the sealing device 1 (schematically shown in FIG. 1 ) during operation of the compressor. Figure 7a The friction on the contact surface between the two is shown in the cross-sectional view EE).

[0090] In particular, in the case of a sealing ring 14 with a high degree of pressure compensation (e.g. a large number of relief openings 25, a small circumferential spacing z between the relief openings, a small axial spacing x between the relief openings), it may happen that during operation, due to the high degree of pressure compensation, the sealing ring 14 is pressed radially against the piston rod 2 only with a relatively small resultant force (e.g. see Figure 5b ). Without the compensating recess 32, due to the friction on the contact surface between the first axial ring end RE1 and the housing segment 3i, the sealing ring 14 may in some cases only insufficiently follow the lateral movement of the piston rod 2 that may occur during operation, which may cause the sealing ring 14 to lift off the piston rod 2 in the radial direction and thus cause undesirable leakage. The friction force that counteracts the lateral movement of the sealing ring 14 is reduced by the compensating recess 32, so that the sealing ring 14 can better follow the movement of the piston rod 2 in the radial direction. The compensating recess 32 can be constructed in different ways, as shown below according to Figures 7a to 7d As described in detail, the left side shows a ring segment 14 a in a top view, while the right side shows a sectional view according to the corresponding section line.

[0091] exist Figure 7a The compensating recess 32 has a width b AThe compensating recess 32 is formed in the form of an elongated groove having a first compensating recess end 32a and a second compensating recess end 32b spaced apart from the first compensating recess end at a certain angle in the circumferential direction, as can be seen on the left side of the figure. The maximum extension h of the compensating recess 32 in the radial direction, which can be seen in the sectional view EE, is A Preferably, it is 60% of the radial ring height RH. This ensures that a sufficiently large static sealing surface is still available on the first axial ring end RE1, which is in contact with the contact surface on the housing segment 3i to achieve radial sealing. The maximum extension h of the compensating recess 32 in the radial direction is A This applies regardless of the structural design of the compensating recess 32 . The maximum compensating recess depth t of the compensating recess 32 in the axial direction of the sealing ring 14 is A Between 1-40% of the ring width RB of the sealing ring 14, preferably 0.5 mm, wherein this also depends on the specific design of the compensating recess 32 ( Figures 7a to 7d ) applies irrelevantly.

[0092] according to Figure 7b The construction of the embodiment has a plurality of separate compensating recesses 32 which are spaced apart from one another in the circumferential direction, as shown in the top view on the left. As a result, the compensating recesses 32 arranged on the outside in the circumferential direction (at the segment ends SE1, SE2) can have different dimensions, for example, than the compensating recesses 32 arranged between them, whereby the contact pressure can be varied in the circumferential direction. The sectional view FF shown on the right again shows the extension of the corresponding compensating recess 32 in the radial direction. A and the compensation recess depth t A .

[0093] Figure 7c The structural scheme of the compensation recess 32 in Figure 7a The structural scheme in FIG. 1 is different in that the compensating recess 32 has an additional compensating recess opening 32c in the area between the first compensating recess end 32a and the second compensating recess end 32b in the circumferential direction, which connects the compensating recess 32 radially to the radially outer peripheral surface 23, as can be seen in the left-hand top view. The sectional view GG shown on the right again shows the extension h of the compensating recess 32 in the radial direction. A and the compensation recess depth t A .

[0094] Figure 7d A further embodiment of the compensating recess 32 is shown, wherein the compensating recess 32 is connected to the outer circumferential surface 23 of the sealing ring radially in the circumferential direction over its entire extension, as shown in the left-hand top view. This results in a relatively large contact surface on the housing segment 3i, and the high pressure P on the cylinder side isH can act on the contact surface, thereby, compared with the Figures 7a to 7c The axial pressing force of the sealing ring 14 on the housing segment 3i can be further reduced. The sectional view HH shown on the right shows the extension of the corresponding compensating recess 32 in the radial direction. A and the compensation recess depth t A .

[0095] However, the variants shown are of course only exemplary and are intended to illustrate in a non-restrictive manner possible structural configurations of the compensating recess 32. A person skilled in the art can of course also specify other configurations of the compensating recess 32.

[0096] exist Figures 8a to 8d 1 shows an exemplary embodiment of a further advantageous embodiment of the sealing ring 14 according to the invention with reference to the ring segment 14a. As already described, a plurality of relief openings 25 are provided on the sealing ring 14, wherein each ring segment 14a is provided with four relief openings 25, which are spaced apart from one another by a relief opening circumferential spacing z. However, the relief opening circumferential spacing z does not have to be of equal length between all relief openings 25 (as shown), but can also be different, for example.

[0097] According to another advantageous construction of the present invention, at least one starting recess 33 is provided on the radially inner inner circumference 18 of at least one ring segment 14a of the sealing ring 14. The at least one starting recess 33 extends in the axial direction of the ring segment 14a from the second axial ring end RE2 via a portion of the ring width RB in the direction of the first axial ring end RE1. In the radial direction of the ring segment 14a, the starting recess 33 extends from the radially inner inner circumference 18 of the ring segment 14a over a small portion of the ring height RH in the direction of the radially outer outer circumference 23 of the ring segment 14a. In the circumferential direction, the starting recess 33 is spaced apart from the corresponding segment ends SE1, SE2. Figure 8d An isometric view of the ring segment 14a is shown, wherein the activation recess 33 is clearly visible. In the example shown, only one activation recess 33 is provided on the ring segment 14a, but it is of course also possible that a plurality of activation recesses 33 which are smaller than the activation recess 33 shown are arranged side by side in the circumferential direction at a distance from one another on the ring segment 14a.

[0098] The provision of the starting recess 33 is used in particular in the case of highly pressure-compensated sealing rings 14 (e.g., multiple relief openings 25, small circumferential spacing z of the relief openings and small axial spacing x of the relief openings). In the case of such sealing rings 14, increased leakage may occur when the compressor is started from a stationary state, because the radial pressing force pressing the sealing ring 14 against the piston rod 2 is in some cases insufficient to compensate for manufacturing-induced tolerances or possible burrs on the sealing ring 14 and / or on the piston rod 2. By providing at least one starting recess 33, the sealing ring 14 rests on the piston rod 2 at the start of the starting phase on a relatively small starting surface 34 compared to the entire inner circumference 18 located radially inward. As a result, the pressure-induced pressure per unit area on the starting surface 34 is increased at the start of the starting phase, which leads to an improved sealing effect and thus to less leakage. The starting phase is to be understood here not only as the first start of the piston compressor, but also as each start from a stationary state (at least as long as the starting surface 34 is present). Preferably, the at least one activation recess 33 is dimensioned so that the remaining activation surface 34 of the ring segment 14a accounts for between 25% and 75%, preferably 60%, of the inner circumference 18 of the ring segment 14a. If a plurality of activation recesses 33 are provided on the ring segment 14a, the area ratio is the ratio of the sum of the individual areas of the activation recesses 33 to the inner circumference 18 of the ring segment 14a.

[0099] exist Figure 8a 1 shows the ring segment 14a of the sealing ring 14 in a view orthogonal to the radially inner inner circumferential surface 18. H Starting from the second axial ring end RE2, the start recess 33 extends over a partial ring height RB in the direction of the first axial ring end RE1, at which a pressure P which is lower than the high pressure prevails during operation. N The starting recess width b in the axial direction of the sealing ring 14 AL Preferably it is 30% to 90%, in particular 65%, of the axial ring width RB in order to exert a sufficiently high effect during the start-up of the compressor. Figure 8a In the figure, the first relief opening ends 25a of the relief opening 25 can be seen, which are respectively spaced apart from each other in the circumferential direction by a relief opening circumferential spacing z (measured from mutually facing delimiting portions of the relief opening ends 25a).

[0100] Figure 8b Show according to Figure 8a A radial cross-sectional view of the ring segment 14a along the section line II. Figure 8c Shown in accordance with Figure 8b A longitudinal sectional view of the ring segment 14a along the section line JJ. Figure 8cIt can be seen that the radial start recess depth t is relatively small compared to the radial ring height RH AL The radial start recess depth fluctuates within a range of 1% to a maximum of 3% of the radial ring height RH, particularly preferably 2%. AL , the starting characteristics are improved as described, without fundamentally changing the characteristics of the sealing ring 14 during normal operation of the compressor. Therefore, the starting recess 33 is not a circumferential groove in the traditional sense, which connects the relief openings 25 and therefore does not promote pressure compensation during operation of the compressor or the promoting effect is so small that it can be ignored. After the starting surface 34 is worn, the sealing ring 14 exhibits the same characteristics as a ring without the starting recess 33. Therefore, within the scope of the present invention, the relief opening end 25a of the relief opening 25 directly merging into the radially inner inner circumferential surface 18 can also be understood as merging into the starting recess 33. That is, according to Figure 5b The pressure conditions shown also apply in principle to the sealing ring 14 with the actuating recess 33. If a plurality of actuating recesses 33 are provided on the sealing ring 14, for example one actuating recess 33 per ring segment 14a (as shown), or a plurality of actuating recesses 33 per ring segment 14a, these actuating recesses can also be designed differently. For example, the actuating recesses 33 can have different radial actuating recess depths t AL and / or different shapes and / or different starting recess widths b in the axial direction AL , in order to be able to configure the start-up characteristics of the sealing ring 14 in a more variable manner. However, the boundary conditions, in particular with respect to the remaining start-up surface 34, remain unchanged. Due to manufacturing conditions, the start-up recess 33 may under certain circumstances also have a certain radius at the edge, which is caused, for example, by the geometry of the tool used, such as a milling cutter.

[0101] exist Figure 8b The sectional view II in FIG. 1 again shows the relief opening 25 and the wear opening 27 in different variants. The relief opening 25-1 arranged at the second segment end SE2 of the ring segment 14a is distinguished from the other three relief openings 25-2. The relief opening 25-2 is implemented as a cylindrical through hole and has an extension in the radial direction of the sealing ring 14 or, in this case, the ring segment 14a. As a result, the relief opening 25-2 is not arranged obliquely (such as, for example, in the radial direction of the ring segment 14a). Figure 2 4), i.e., with a relief opening angle ε=0. That is, the relief opening 25-2 extends parallel to the first and second ring ends RE1, RE2, as in Figure 8c As can be seen in .

[0102] The relief opening 25-1 provided at the second segment end SE2 of the ring segment 14a extends in a direction deviating from the radial direction of the ring segment 14a. Figure 2 + Figure 6 DD in FIG. 8 ), the relief opening 25-1 is arranged so that although it is in the sectional plane shown in FIG. 8 , i.e. parallel to the first and second ring ends RE1, RE2, it deviates from the radial direction in the sectional plane by a second relief opening angle ω. This basically means that the second relief opening end 25-1b that merges into the radially outer peripheral surface 23 of the sealing ring 14 is spaced apart in the circumferential direction from the first relief opening end 25-1a that merges into the inner peripheral surface 18 that is located inside, as shown in FIG. Figure 8b As shown in .

[0103] The spacing between the relief opening ends 25-1a, 25-1b is obtained by the product ω*Da of the relief opening angle ω and the outer diameter Da of the sealing ring 14. By the inclined setting of the relief opening 25-1, pressure compensation can also be achieved in the section of the inner peripheral surface 18 located inside and close to the second segment end SE2. Based on the overlap of the segment ends SE2 and SE1 of the two adjacent ring segments 14a, such pressure compensation may not be achieved or difficult to achieve with the help of a radially extending relief opening 25 similar to the relief opening 25-2. However, it is certainly conceivable that one or more relief openings 25 are provided on the sealing ring 14 or the ring segment 14a, and the relief openings are not only arranged at the first relief opening angle ε, but also at the second relief opening angle ω, deviating from the radial direction. This means that the first relief opening end 25a may be spaced apart from the second relief opening end 25b not only in the axial direction, but also in the circumferential direction.

[0104] The two wear openings 27 extend here in the radial direction of the ring segment 14a. Figure 8b As can be seen in the figure, the two have different depths t v1 >t v2 The wear opening 27 extends from the radially outer peripheral surface 23 of the sealing ring 14 in the direction of the radially inner inner peripheral surface 18. v1 In the case of v1 The wear opening 27, and the wear intensifies v = RH-t v2 The case reveals a depth t v2 The wear opening 27 is provided. Thus, the pressure compensation is basically realized in two stages. Of course, it is also possible to provide more or fewer wear openings 27 and / or unloading openings 25. In addition to or instead of the different depths tv One or more wear openings 27 may also be arranged obliquely with respect to the radial direction of the sealing ring 14 at a first wear opening angle φ (see Figure 6 CC in the cross-sectional view) and / or arranged obliquely at a second wear opening angle λ (not shown) similar to the second relief opening angle ω, as already described Figure 8b As shown in .

[0105] Depending on the application, the embodiments of the invention shown can of course be combined in any desired way to achieve the desired result, in particular the desired pressure compensation of the sealing ring 14. Preferably, at least one sealing ring 14 according to the invention is arranged Figure 1 In the sealing device 1 of the piston compressor shown in FIG. 1 , it is particularly preferred that a plurality of sealing rings 14 according to the present invention are arranged one after the other in the axial direction.

[0106] Finally, it should be pointed out again that Figures 1 to 8d The features described and shown in the embodiments shown in the drawings are to be regarded as independent of one another and can of course also be used individually or in any desired combination. The sealing ring 14 does not necessarily have to be as in Figure 2 14a. In a very simple case, the sealing ring 14 according to the invention may include three relief openings 25 of any shape on at least one ring segment 14a, which extend from the inner circumferential surface 18 to the outer circumferential surface 23 and / or to the second axial ring end RE2 of the ring segment 14a, wherein the first relief opening ends 25a are spaced apart from each other on the inner circumferential surface 18 at a specific relief opening circumferential spacing z and are spaced apart from the first axial ring end RE1 at a relief opening axial spacing x, which is 4%-20% of the axial ring width RB of the ring segment 14a. Optionally, one or more relief openings 25 may be implemented obliquely and / or one or more wear openings 27 may be provided, one or more of which may also be oblique. In addition, one or more compensation recesses 32 and / or start recesses 33 may be optionally provided on the sealing ring 14.

Claims

1. A sealing ring (14), the sealing ring comprising at least three ring segments (14a), the ring segments each comprising a first segment end (SE1) and a second segment end (SE2) in a circumferential direction, wherein: A first tangential contact surface (19a) of a first segment end (SE1) of a ring segment (14a) abuts against a second tangential contact surface (19b) of a second segment end (SE2) of a ring segment (14a) connected to the ring segment in a circumferential direction, so as to produce a radial seal of the sealing ring (14), and a first axial contact surface (16) of a first axial ring end (RE1) of a first segment end (SE1) of a ring segment (14a) facing the sealing ring (14) abuts against a second axial contact surface (17) of a second segment end (SE2) of a ring segment (14a) connected to the ring segment in a circumferential direction, facing the sealing ring (14), so as to produce an axial seal of the sealing ring (14), and at least three relief openings (25) are provided on at least one ring segment (14a), the relief openings being arranged from a radial position of the ring segment (14a) to a position adjacent to the ring segment (14a). Starting from the inner circumferential surface (18), the relief openings (25) extend to the radially outer circumferential surface (23) of the ring segment (14a) and / or extend to the second axial ring end (RE2). Each relief opening (25) has a first relief opening end (25a) that merges into the radially inner circumferential surface (18) of the ring segment (14a). The first relief opening ends (25a) of the two relief openings (25) arranged side by side in the circumferential direction are arranged to be spaced apart from each other by a relief opening circumferential spacing (z). It is characterized in that the first relief opening end (25a) is closer to the first axial ring end (RE1) than the second axial ring end (RE2) in the axial direction and is spaced apart from the first axial ring end (RE1) by a relief opening axial spacing (x), and the relief opening axial spacing is 4% to 20% of the axial ring width (RB) of the ring segment (14a).

2. The sealing ring (14) according to claim 1, characterized in that At least three relief openings (25) are provided on each ring segment (14a).

3. The sealing ring (14) according to claim 1, characterized in that The circumferential spacing (z) of the unloading openings is 1 mm to 15 mm.

4. The sealing ring (14) according to claim 1, characterized in that The circumferential spacing (z) of the unloading openings is 2 mm.

5. The sealing ring (14) according to any one of claims 1 to 4, characterized in that The circumferential spacing (z) between all the relief openings (25) in a ring segment (14a) is of equal length.

6. The sealing ring (14) according to claim 1, characterized in that The at least three relief openings (25) have a relief opening length in the circumferential direction at least at their relief opening ends (25a), and the relief opening length is 2%-100% of the axial ring width (RB) of the sealing ring (14).

7. The sealing ring (14) according to claim 1, characterized in that The at least three relief openings (25) have a relief opening length in the circumferential direction at least at their relief opening ends (25a), and the relief opening length is 2%-50% of the axial ring width (RB) of the sealing ring (14).

8. The sealing ring (14) according to claim 1, characterized in that The at least three relief openings (25) each have a relief opening length in the circumferential direction at least at their relief opening ends (25a), and the relief opening length is at most 25% of the axial ring width (RB) of the sealing ring (14).

9. The sealing ring (14) according to claim 1, characterized in that At least one section of the at least one relief opening (25) adjoining the radially inner inner circumferential surface (18) of the sealing ring (14) is inclined or curved in the direction of the first axial ring end (RE1).

10. The sealing ring (14) according to claim 1, characterized in that At least one relief opening (25) is provided, wherein a first relief opening end (25a) of the relief opening which opens into a radially inner inner circumferential surface (18) of the sealing ring (14) is spaced apart in the circumferential direction from a second relief opening end (25b) of the relief opening (25) which opens into a radially outer outer circumferential surface (23) of the sealing ring (14).

11. The sealing ring (14) according to claim 1, characterized in that At least one axial groove (24) is provided on a radially outer outer circumferential surface (23) of at least one ring segment (14a), said axial groove extending from a first axial ring end (RE1) to a second axial ring end (RE2).

12. The sealing ring (14) according to claim 1, characterized in that At least one axial groove (24) is provided on a radially outer circumferential surface (23) of each ring segment (14a), which extends from a first axial ring end (RE1) to a second axial ring end (RE2).

13. The sealing ring (14) according to claim 1, characterized in that The at least three relief openings (25) each have an axial relief opening width at least at their relief opening ends (25a), and the axial relief opening width is 2%-30% of the axial ring width (RB) of the sealing ring (14).

14. The sealing ring (14) according to claim 1, characterized in that The at least three relief openings (25) each have an axial relief opening width at least at their relief opening ends (25a), and the axial relief opening width is 2%-20% of the axial ring width (RB) of the sealing ring (14).

15. The sealing ring (14) according to claim 13 or 14, characterized in that At least one relief opening (25) has a straight extension and a constant circular cross section with a relief opening diameter (d E ), the unloading opening diameter is between 2% and 30% of the axial ring width (RB) of the sealing ring (14).

16. The sealing ring (14) according to claim 13 or 14, characterized in that At least one relief opening (25) has a straight extension and a constant circular cross section with a relief opening diameter (d E ), the unloading opening diameter is between 2% and 20% of the axial ring width (RB) of the sealing ring (14).

17. The sealing ring (14) according to claim 1, characterized in that At least one wear opening (27) is provided on at least one ring segment (14a), and the wear opening extends from a radially outer peripheral surface (23) and / or a second axial ring end (RE2) of the ring segment (14a) in the direction of a radially inner inner peripheral surface (18) of the ring segment (14a), wherein a radially inner wear opening end (27a) of the at least one wear opening (27) facing the inner peripheral surface (18) is spaced apart from the radially inner inner peripheral surface (18) of the ring segment (14a) in the radial direction of the ring segment (14a) by a distance that is at most 40% of a radial ring height (RH) extending between the outer peripheral surface (23) and the radially inner inner peripheral surface (18) of the ring segment (14a), wherein the wear opening end (27a) is located between the first and second axial ring ends (RE1, RE2) and is spaced apart from the first and second axial ring ends (RE1, RE2).

18. The sealing ring (14) according to claim 17, characterized in that At least one end section of at least one wear opening (27) facing the radially inner inner circumferential surface (18) is inclined in the direction of the first axial ring end (RE1).

19. The sealing ring (14) according to claim 17 or 18, characterized in that At least one wear opening (27) has a straight extension and a constant circular cross section with a wear opening diameter (d v ), the wear opening diameter is 2%-60% of the axial ring width (RB) of the sealing ring (14).

20. The sealing ring according to claim 17 or 18, characterized in that The at least one wear opening (27) is spaced apart from the first axial ring end (RE1) in the axial direction by a wear opening axial spacing (y), the wear opening axial spacing being 2% to 20% of the axial ring width (RB).

21. The sealing ring (14) according to claim 1, characterized in that At least one compensating recess (32) is provided on at least one ring segment (14a), which extends from a radially outer outer circumferential surface (23) of the ring segment (14a) in the direction of a radially inner inner circumferential surface (18) of the ring segment (14a) and from a first axial ring end (RE1) in the direction of a second axial ring end (RE2).

22. The sealing ring (14) according to claim 21, characterized in that At least one compensating recess (32) is provided on each ring segment.

23. The sealing ring (14) according to claim 1, characterized in that At least one starting recess (33) is provided on the radially inner inner circumferential surface (18) of at least one ring segment (14a), the starting recess extending in the axial direction of the ring segment (14a) from the second axial ring end (RE2) in the direction of the first axial ring end (RE1) and in the radial direction of the ring segment (14a) from the radially inner inner circumferential surface (18) of the ring segment (14a) in the direction of the radially outer outer circumferential surface (23) of the ring segment (14a) so as to form a smaller starting surface (34) relative to the entire radially inner inner circumferential surface (18), the starting recess (33) having a radial starting recess depth (t AL ), the maximum depth of the radial starting recess is 3% of the ring height (RH), and the first relief opening end (25a) of the at least three relief openings (25) merges into the radially inner inner circumferential surface (18) after the starting surface (34) is worn.

24. A sealing device (1) for sealing a piston rod (2) that moves in a translational reciprocating manner, the sealing device comprising a housing (3) in which a plurality of sealing rings (7) arranged axially one after the other are arranged, wherein: At least one sealing ring (14) according to any one of claims 1 to 23 is provided.

25. A piston compressor comprising a compressor housing and at least one cylinder housing arranged on the compressor housing, in which a piston performs a translational reciprocating motion, wherein: The piston is connected via a piston rod to a crankshaft arranged in a compressor housing, and the piston compressor has at least one sealing ring (14) according to any one of claims 1 to 23, which is arranged in the compressor housing for sealing the piston rod.

26. The piston compressor according to claim 25, characterized in that A sealing arrangement (1) having a housing (3) is provided in the compressor housing, in which a plurality of sealing rings (7) arranged axially one after the other are provided, wherein at least one sealing ring (14) according to any one of claims 1 to 23 is provided.

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