Sealing ring assembly with split expander

Abstract

Sealing ring assemblies are described herein with corresponding installation tools. The sealing ring assemblies include a split ring expander and a self-lubricating ring segment. The self-lubricating ring segment includes a radially outward surface for forming a seal against a bore of a cylinder and a feature to constrain at least axial movement of the split ring expander relative to the self-lubricating ring segment. A radially outward surface of the split ring expander imparts a radially outward force on the feature and one or more other ring segments of the sealing ring assembly.

Description

Docket No. 000102-0045-W01SEALING RING ASSEMBLY WITH SPLIT EXPANDERCross-Reference to Related Applications

[0001] This application claims the benefit of U.S. Provisional Patent Application No.63 / 740,169 filed December 30, 2024, the disclosure of which is hereby incorporated by reference herein in its entirety.Field of Disclosure

[0002] The present disclosure is directed to sealing ring assemblies including an expander ring, and more particularly, to sealing ring assemblies with a plurality of sealing ring segments that propagate radially outward based on a force generated by a radially inward expander ring (e.g., after installation into a circumferential groove of a piston using a tool).Summary

[0003] A reciprocating compression device, such as the reaction section of a linear generator, includes a piston translating axially within a cylinder. The piston forms one wall of a sealed chamber within the cylinder. As the piston translates towards the opposite wall, which may itself be a second piston assembly, gas pressure rises within the chamber. A sealing ring assembly located at the outer diameter (OD) surface of the piston separates the higher pressure gas within the chamber from the lower pressure outside of the chamber. The ring assembly forms a first continuous line of contact against the piston, and a second continuous line of contact against the inner surface of the cylinder, creating a seal.

[0004] In some circumstances, a radially outward force may be provided on the sealing ring, independent of pressure within the chamber, to ensure sealing contact between the outer surface of the ring assembly and the inner surface of the cylinder. For example, in the case of a linear generator, during the gas exchange portion of the cycle it can occur that the pressure outside the chamber is temporarily higher than inside the chamber - a reverse pressure gradient compared to the normal direction of sealing. The reverse pressure gradient can cause the seal assembly to collapse radially inward. An outward force bias that does not depend on pressure, provided for example by a spring, may counteract the reverse pressure and maintain the seal contact against the cylinder.

[0005] The present disclosure provides mechanisms for generating the outward radial force by way of relative bending of portions of an approximately circular beam with a single split.The split ring forms a cantilever beam but pushes against itself rather than having one end fixed to the piston. The resulting split ring shares some similarities with conventional generator piston rings, but with some novel features relevant to the application as an expander integrated into a segmented sealing ring assembly.

[0006] The present disclosure, in some embodiments, is generally directed to a sealing ring assembly including a split ring expander and a self-lubricating ring segment. The selflubricating ring segment includes a radially outward surface for forming a seal against a bore of a cylinder and a feature to constrain at least axial movement of the split ring expander relative to the self-lubricating ring segment. A radially outward surface of the split ring expander imparts a radially outward force on the feature and one or more other ring segments of the sealing ring assembly.

[0007] In some embodiments, the feature is a circumferential groove embedded in a radially inward surface of the self-lubricating ring segment. Additionally, or alternatively, the circumferential groove is configured to receive at least a portion of the split ring expander. In some embodiments, the split ring expander comprises at least one feature that extends radially outward. Additionally, or alternatively, the at least one feature comprises one or more of a wall or a flange.

[0008] In some embodiments, at least a portion of the split ring expander has a T-shaped cross-sectional geometry. In some embodiments, at least a portion of the split ring expander a L-shaped cross-sectional geometry. Additionally, or alternatively, at least a portion of the split ring expander comprises a C-shaped cross-sectional geometry.

[0009] In some embodiments, the feature includes a pair of protrusions extending radially from a radially inward surface of the self-lubricating ring segment. The pair of protrusions may at least partially form a circumferential groove configured to receive at least a portion of the split ring expander. Additionally, or alternatively, the self-lubricating ring segment further comprises a pressure locking feature configured to interface with the split ring expander. In some embodiments, the pressure locking feature interfaces with a radially extending feature of the split ring expander. Additionally, or alternatively, the pressure locking feature comprises a through feature extending from a first axial surface of the selflubricating ring segment to a second axial surface of the self-lubricating ring segment.

[0010] In some embodiments, the pressure locking feature may connect a first pressurized region to a second pressurized region. A pressure difference between the first pressurized region and the second pressurized region corresponds to a suction force realized through the pressure locking feature that draws the split ring expander towards an axial surface of theself-lubricating ring segment. The suction force may, in some embodiments, be realized through the pressure locking feature is applied to the split ring expander to prevent axial movement of the split ring expander relative to the axial surface of the self-lubricating ring segment.

[0011] In some embodiments, the split ring expander includes a pair of opposed ends and each end of the pair of opposed ends includes a respective radially flared feature.Additionally, or alternatively, each end of the pair of opposed ends comprises a respective portion that is radially wider than a respective azimuthally adjacent portion of the split ring expander. In some embodiments, the split ring expander comprises a pair of radially curved beams. Each beam of the pair of radially curved beams may be radially tapered.

[0012] In some embodiments, each beam of the pair of radially curved beams includes a respective opposed end. Each beam of the pair of radially curved beams may incorporate a respective tapered profile that narrows each beam of the pair of radially curved beams towards each respective opposed end.

[0013] In some embodiments, wherein the split ring expander includes a protrusion that extends radially inward from a radially inward surface of the split ring expander. The protrusion is configured to reduce at least one of stress or strain of one or more axial or radial surfaces of the split ring expander.

[0014] In some embodiments, the sealing ring assembly incorporates at least one anticlocking feature configured to at least one of reduce or prevent one or more of azimuthal or rotational movement of the split ring expander relative to the self-lubricating ring segment. Additionally, or alternatively, the split ring expander has a protrusion extending from a radially outward surface of the split ring expander and the self-lubricating ring segment has a notch embedded in a radially inward surface of the self-lubricating ring segment. In some embodiments, the notch is configured to receive the protrusion to prevent azimuthal rotation of the split ring expander relative to the self-lubricating ring segment.

[0015] In some embodiments, the split ring expander is formed of metal. The metal may, in some embodiments, be one or more of at least one steel or at least one superalloy (e.g., a superalloy comprising at least nickel).

[0016] In some embodiments, the self-lubricating ring segment is formed of graphite. Additionally, or alternatively, the radially outward surface is a first radially outward surface andthe self-lubricating ring segment includes a second radially outward surface. The second radially outward surface may be radially inward relative to the first radially outward surfaceand the second radially outward surface may be configured to contact a radially adjacent ring segment of the sealing ring assembly.

[0017] The present disclosure, in some embodiments, is generally directed to a sealing ring assembly with a self-lubricating ring segment (e.g., self-lubricating carbon graphite or other suitable self-lubricating material including other forms for graphite) and an expander including contacting a radially inward surface of the graphite ring segment. The graphite ring segment incorporates a first feature and a radially outward surface for forming a seal against a bore of a cylinder. The expander incorporates a second feature that is configured to engage with the first feature to constrain relative movement between the graphite ring segment and the expander. A radially outward surface of the expander imparts a radially outward force on the first feature and one or more other ring segments of the sealing ring assembly.

[0018] In some embodiments, the graphite ring segment further comprises a circumferential groove and the first feature comprises a notch. Additionally, or alternatively, the notch is embedded in a surface of the circumferential groove. The circumferential groove may be arranged on a radially inward surface of the graphite ring segment. In some embodiments, the second feature comprises a protrusion. Additionally, or alternatively, the second feature comprises an anti-rotation clocking feature which may extend from the radially outward surface of the expander.

[0019] In some embodiments, the expander is a split ring expander with a pair of opposed ends. Each respective end of the pair of opposed ends may incorporate a respective feature such that each respective end is radially wider than respective portions of the split ring expander proximate to each respective end. Additionally, or alternatively, the second feature is arranged on a first radial side of the split ring expander that is radially opposite from a second radial side of the split ring expander that comprises the pair of opposed ends.

[0020] In some embodiments, each respective opposed split end of the pair of opposed split ends includes a respective radially flared feature that is angled to match a seal wedge angle of a corresponding surface of a sealing ring segment configured to interface with each respective radially flared feature.

[0021] In some embodiments, where the expander is a split ring expander, the second feature may be a protrusion that extends radially outward from a radially outward surface of the split ring expander. A pair of disconnected ends of the split ring expander may be arranged azimuthally opposite the second feature. Additionally, or alternatively, a cross-sectional area of the split ring expander comprises a T-shaped geometry. In some embodiments, the second feature further comprises a pair of radial notches. Each respectivenotch of the pair of radial notches may be azimuthally displaced from a respective disconnected end of the pair of disconnected ends. Additionally, or alternatively, each respective notch may be configured to impart one or more of a radially outward force or an azimuthally outward force against an end of a slot extending along a radially inward surface a ring segment arranged radially adjacent to the graphite ring segment. In some embodiments, the slot extending along the radially inward surface receives the protrusion.

[0022] In some embodiments, where the expander is a split ring expander, a pair of disconnected ends of the split ring expander include respective radially flared portions.Additionally, or alternatively, a cross-sectional area of the split ring expander comprises a U-shaped geometry.

[0023] In some embodiments, where the expander is a split ring expander, a flange extends azimuthally, from an axial end of the split ring expander, around an outer surface of the split ring expander. Additionally, or alternatively, a cross-sectional area of the split ring expander comprises a L-shaped geometry.

[0024] In some embodiments, the sealing rings of this disclosure include at least one adjacent ring segment. The at least one other adjacent ring segment may be formed of graphite to include a stepped surface configured to contact a radially angled surface of the graphite ring segment, and a through feature extending from a first axial surface of the at least one other adjacent ring segment to a second axial surface of the at least one other adjacent ring segment and a radially inward corner. Additionally, or alternatively, a vertex of the L-shaped geometry is drawn to contact the radially inward corner based at least in part on a pressure difference between a first pressurized region in contact with the first axial surface and a second pressurized region in contact with a radially inward surface of the L-shaped geometry.

[0025] In some embodiments, the graphite ring segment includes a wedge shaped surface that is at least one of axially or radially displaced from the radially outward surface. The wedge shaped surface comprises a pair of radially angled surfaces. Additionally, or alternatively, each respective radial angle of each of angled surface of the pair of radially angled surfaces is based on one or more of a wear rate of graphite comprising the radially outward surface or spring rate of one or more arms of the expander.

[0026] In some embodiments, the sealing ring assembly includes at least one adjacent ring segment, formed of graphite, with a stepped surface that may contact a radially angled surface of the pair of radially angled surfaces. Additionally, or alternatively, the at least one adjacent ring segment has a first axial thickness that is different from a second axial thicknessof the graphite ring segment. In some embodiments, the at least one adjacent ring segment has a varying axial thickness from one radial end of the at least one adjacent ring segment to an opposite radial end of the at least one adjacent ring segment.

[0027] In some embodiments, the graphite ring segment is a first radially outward ring segment and sealing ring assemblies of this disclosure include at least one other radially outward ring segment along with at least one radially inward ring segment that contacts at least one of a first radial end of the first radially outward ring segment or a second radial end of the at least one other radially outward ring segment. Additionally, or alternatively, the sealing ring assembly may include a same number of radially inward ring segments and radially outward ring segments.

[0028] In some embodiments, the disclosure is directed to a device including a cylinder assembly comprising a bore, a piston assembly configured to translate axially along the bore during operation of the device, and a sealing ring assembly. The sealing ring assembly includes a split ring expander and a self-lubricating ring segment. The self-lubricating ring segment has a radially outward surface for forming a seal against a bore of a cylinder, and a feature to constrain at least axial movement of the split ring expander relative to the selflubricating ring segment. A radially outward surface of the split ring expander is configured to impart a radially outward force on the feature and one or more other ring segments of the sealing ring assembly.

[0029] In some embodiments, the disclosure is directed to a device including a cylinder assembly with a bore, a piston assembly to translate axially along the bore during operation of the device, one or more sealing ring assemblies of this disclosure. The piston assembly, in some embodiments, includes a piston face, an axially front land extended from a radially outward portion of the piston face, an axially rear land, a plurality of sealing ring retainers that extend radially outward from the axially front land, a circumferential groove formed between the axially front land and the axially rear land, wherein the sealing ring assembly is configured to occupy the circumferential groove.

[0030] In some embodiments, the disclosure is directed to a sealing ring installation tool for installing one or more sealing ring assemblies of this disclosure in circumferential grooves of one or more devices of this disclosure. The tool includes a pronged portion, a pair of curved arms, wherein each respective end of each curved arm of the pair of curved arms is pivotably coupled to azimuthally opposite ends of the pronged portion, and a pin. In some embodiments, the pin comprises a quick release pin. Additionally, or alternatively, the tool may be formed out of machined aluminum.

[0031] In some embodiments, the installation tool includes a lanyard, a pair of azimuthally spaced prongs, and a pair of azimuthally spaced spring loaded plungers to preload the ring segment against the pair of azimuthally spaced prongs. Additionally, or alternatively, each curved arm of the pair of curved arms has at least one segment retaining plunger. The at least one segment retaining plunger may radially retain at least one ring segment between an axially front land of a piston and an axially rear land of a piston in a circumferential groove.

[0032] In some embodiments, the disclosure is directed to a method of installing a sealing ring assembly of this disclosure in a circumferential groove of a device of this disclosure using one or more features of example installation tools described herein.Brief Descriptions of the Drawings

[0033] The present disclosure, in accordance with one or more various embodiments, is described in detail with reference to the following figures. The drawings are provided for purposes of illustration only and merely depict typical or example embodiments. These drawings are provided to facilitate an understanding of the concepts disclosed herein and shall not be considered limiting of the breadth, scope, or applicability of these concepts. It should be noted that for clarity and ease of illustration these drawings are not necessarily made to scale.

[0034] The above and other objects and advantages of the disclosure may be apparent upon consideration of the following detailed description, taken in conjunction with the accompanying drawings, in which:

[0035] FIG. 1 illustrates an example sealing ring assembly including an expander ring, in accordance with some embodiments of the disclosure;

[0036] FIG. 2 A illustrates a cross-sectional view of a sealing ring segment including an example expander ring, in accordance with some embodiments of the disclosure;

[0037] FIG. 2B illustrates an example sealing ring segment interfacing with a radial protrusion of an example expander ring, in accordance with some embodiments of the disclosure;

[0038] FIG. 2C illustrates an example sealing ring segment interfacing with a radial channel of an example expander ring, in accordance with some embodiments of the disclosure;

[0039] FIG. 2D illustrates an example sealing ring segment with an example radial protrusion interfacing with a radial channel of an example expander ring, in accordance with some embodiments of the disclosure;

[0040] FIG. 2E illustrates an example sealing ring segment with a pressure locking feature interfacing with a radial vertex of an example expander ring, in accordance with some embodiments of the disclosure;

[0041] FIG. 3 A illustrates an example expander for pressing ring segments (not shown) radially outward, in accordance with some embodiments of the disclosure;

[0042] FIG. 3B illustrates an example expander for pressing ring segments (not shown) radially outward with a radially extending protrusion, in accordance with some embodiments of the disclosure;

[0043] FIG. 3C illustrates an example notch at a radial end of the radially extending protrusion of FIG 3B, in accordance with some embodiments of the disclosure;

[0044] FIG. 3D illustrates an example expander for pressing ring segments (not shown) radially outward based on an example radial channel, in accordance with some embodiments of the disclosure;

[0045] FIG. 3E illustrates an example expander for pressing ring segments (not shown) radially outward with an example radially extending flange, in accordance with some embodiments of the disclosure;

[0046] FIG. 4A illustrates an example sealing ring segment including an example circumferential groove for receiving at least a portion of an expander (not shown), in accordance with some embodiments of the disclosure;

[0047] FIG. 4B illustrates an example sealing ring segment with material removed for illustrative purposes to expose an example notch that interfaces with a protrusion of an example expander, in accordance with some embodiments of the disclosure;

[0048] FIG. 4C illustrates an example sealing ring segment including a pair of example angled surfaces interfacing with radial ends of an example split expander, in accordance with some embodiments of the disclosure;

[0049] FIG. 5 A illustrates an example sealing ring segment with example steps in an axial surface that modify a contact area of an example radially outward surface, in accordance with some embodiments of the disclosure;

[0050] FIG. 5B illustrates an example sealing ring segment with an example groove in a radially inward surface for receiving radial feature of an expander (not shown), in accordance with some embodiments of the disclosure;

[0051] FIG. 5C illustrates an example sealing ring segment with an example expander seated in a groove of a radially inward surface of the example sealing ring segment, in accordance with some embodiments of the disclosure;

[0052] FIG. 6A illustrates an axially bottom view of an example tool for installing sealing ring segments of, for example, the sealing ring assembly of FIG. 1 in a circumferential groove of a piston, in accordance with some embodiments of the disclosure;

[0053] FIG. 6B illustrates a cross section view of an example release pin of the tool of FIG.6 A, in accordance with some embodiments of the disclosure;

[0054] FIG. 7 illustrates an axially top view of the tool of FIG. 6 A populated with sealing ring segments of the sealing ring assembly of FIG. 1, in accordance with some embodiments of the disclosure;

[0055] FIG. 8A illustrates an example sealing ring segment interfacing with an example split expander as held in place by prongs of the tool of FIG. 6, in accordance with some embodiments of the disclosure;

[0056] FIG. 8B illustrates example points of contact between a section of the tool of FIG. 6 and an example sealing ring segment, in accordance with some embodiments of the disclosure;

[0057] FIG. 9A illustrates an example interface between prongs of the tool of FIG. 6 and an example sealing ring segment, in accordance with some embodiments of the disclosure;

[0058] FIG. 9B illustrates an example arrangement of prongs of the tool of FIG. 6 relative to retainers of an example piston to arrange an example sealing ring segment in an example circumferential groove of a piston, in accordance with some embodiments of the disclosure;

[0059] FIG. 9C illustrates an example fastener interfacing with a section of the tool of FIG.6, in accordance with some embodiments of the disclosure;

[0060] FIG. 10 illustrates an example range of positions of an example expander ring of this disclosure relative to a circumferential groove of an example piston based on the depicted arrangement of an example installation tool interfacing with an example sealing ring segment, in accordance with some embodiments of the disclosure;

[0061] FIG. 11 illustrates a radially outward view of multiple example sealing ring segments interfacing with an example installation tool while arranged in an example circumferential groove of an example piston, in accordance with some embodiments of the disclosure;

[0062] FIG. 12A illustrates an example interface between axial features of an example section of an installation tool of this disclosure and axial surfaces of example ring segments of this disclosure, in accordance with some embodiments of the disclosure;

[0063] FIG. 12B illustrates a perspective view of an entire sealing ring assembly arranged in a circumferential groove of an example piston based on an arrangement of an example installation tool, in accordance with some embodiments of the disclosure;

[0064] FIG. 13 illustrates an axially bottom view of an example relative orientation between example axial retaining features of an example installation tool of this disclosure and retainers of an example piston of this disclosure, in accordance with some embodiments of the disclosure;

[0065] FIG. 14 illustrates an example radial contact surface of a cylinder assembly interfacing with a radially outward surface of an example installed sealing ring assembly, in accordance with some embodiments of the disclosure;

[0066] FIG. 15 is a flow chart representing an illustrative process for using a tool of this disclosure to install a sealing ring assembly of this disclosure in a circumferential groove of a piston, in accordance with some embodiments of the disclosure;

[0067] FIG. 16 illustrates a cross-sectional view of a portion of an illustrative cylinder and piston assembly including an installed sealing ring assembly of this disclosure, in accordance with some embodiments of the disclosure; and

[0068] FIG. 17 illustrates an example device with sealing ring assemblies of this disclosure installed in circumferential grooves of pistons of the example device, in accordance with some embodiments of the disclosure.Detailed Description

[0069] Sealing ring assemblies, devices including the described sealing ring assemblies, and tools for installing the described sealing ring assemblies in the described devices are provided herein.

[0070] While designing piston seals for applications with highly regulated emissions standards, solid lubricant seals (e.g., having self-lubricating material and configured for oilless operation) provide benefits compared to seals requiring liquid lubricants. For example, graphite is a common material used for this application as it has self-lubricating properties. Due to its brittle nature, the strain in graphite seals needs to be restricted as it wears during operation to avoid breakage due to high deformation of its worn shape. As described herein, an expander ring may be installed radially inward of sealing ring segments of a sealing ring assembly so as to enable consistent contact in an azimuthal direction between a radially outward surface of the described sealing ring assemblies and cylinder bores of devices described herein.

[0071] Within a reciprocating machine, such as a linear generator for example, the sealing ring assembly experiences a reversing acceleration force along the axis of the ring. For example, in a linear generator the sealing ring assembly is mounted to the end of the translator assembly. At the inward apex of the translator motion, the sealing assembly experiences an acceleration force in the forward direction. At the outward apex the sealing assembly experiences an acceleration force in the backward direction.

[0072] During the forward acceleration, the seal ring assembly is held backward against the piston in spite of the forward acceleration force due to the axial pressure gradient from the high pressure side (the front) towards the low pressure side (the back) of the seal. During the backward acceleration the seal ring assembly is held back against the piston because the acceleration force points in the backward direction. However, the expander ring can be pressure-neutral, meaning no net axial pressure gradient, due to the expander itself not providing the sealing function. Without some other form of constraint, during the forward acceleration the expander ring would come forward and contact the forward portion of the piston groove. Likewise in the backward direction the expander ring would contact the piston. In the present invention the sealing ring provides an axial constraint to limit axial motion of the expander ring in spite of the axial acceleration forces. The expander ring only contacts the self-lubricating seal ring material and not the metal piston, thus avoiding metalmetal contact and fretting damage.

[0073] The assemblies described and shown herein can be configured for 500 or 600 hours of operation before having to service one or more components of the assembly. Additionally, or alternatively, sealing ring assemblies of this disclosure result in as low as 150 up to 550 parts per million of methane (e.g., CH4) in terms of content of emissions when installed in one or more generators or devices of this disclosure. A split ring expander can be utilized in place of beam springs to cause one or more segments of a sealing ring assembly to be forced radially outward (e.g., to form a seal against a bore of a cylinder).

[0074] FIG. 1 shows sealing ring assembly 100 including expander ring 102, in accordance with some embodiments of the disclosure. As shown in FIG. 1, sealing ring assembly 100 includes a plurality of ring segments. Segments 104 include respective radially outward surfaces 106 that are configured to contact a bore of a cylinder. Extending between, and contacting, segments 104 are other segments 108. Other segments 108 include stepped surfaces 110 which accommodate axial surfaces perpendicular to radially outward surfaces 106. Stepped surfaces 110 are arranged radially opposite of angled interfaces 112 which accommodate a wedge shaped surface of segments 104. As shown in FIG. 1, segments 104are radially forward, or radially in front of, other segments 108 based on the radially positioning of radially outward surfaces 106 of segments 104. Other segments 108 may, in some embodiments, be considered as radially rear ring segments. Other segments 108 are depicted in FIG. 1 as having a varying, or varied, axial thickness between azimuthal, or radial ends. In some embodiments, other segments 108 may comprise a constant axial thickness for at least a portion of the circumferential length of segments 108.

[0075] Expander ring 102 is shown in FIG. 1 as being accommodated by grooves 118 in radially inward surfaces of each of segments 104 and other segments 108. Grooves 118 form a circumferential groove in a radially inward surface of sealing ring assembly 100 to accommodate expander ring 102 and may, in some embodiments, impart a retaining force on outer surfaces of expander ring 102 to prevent azimuthal slipping of one or more of segments 104 or other segments 108. As shown in FIG. 1, expander ring 102 may be a split ring expander with gap 114 between disconnected ends 116. Disconnected ends 116 may include a flange or flanged profile. The flange, or flanged profile, may include features for clocking disconnected ends 116 in circumferential groove 118 of segment 104. The flange, or flanged profile, may also reduce mechanical stress or strain experienced along the circumference of expander ring 102.

[0076] Expander ring 102 may, in some embodiments, be manufactured to a size (e.g., diameter or radial width) that is larger in a free, unstressed, or otherwise unconstrained state than a size when sealing ring assembly 100 with expander ring 102 is installed within a circumferential groove of a device (e.g., a circumferential groove formed between axially forward and axially rearward lands of a piston). During installation, expander ring 102 may be compressed to the smaller installed state which imparts preload stress in a circular beam comprising expander ring 102.

[0077] When sealing ring assembly 100 is installed in a circumferential groove of a piston configured to axially translate along a bore of a cylinder, radially outward surfaces 106 and adjacent outward surfaces 120 wear down such that a radial width of sealing ring assembly 100 decreases as material from sealing ring assembly 100 is worn away based on contact with the bore during axial translation of the piston. Expander ring 102 imparts a spring force along a radially outward direction to maintain contact between radially outward surfaces 106, adjacent outward surfaces 120, and the described cylinder bore. In some embodiments, the magnitude of radial wear of segments comprising sealing ring assembly 100 over a target operational lifetime of sealing ring assembly 100 (e.g., as installed in a described device or described piston assembly) may be up to several millimeters (e.g., up to 5 mm). The radialdifference between the free state and installed state of expander ring 102 may, in some embodiments, be equal to or greater than the anticipated magnitude of radial wear (e.g., up to 5 mm).

[0078] In some embodiments, sealing ring assembly 100 may be in contact with fluids, or gases, of an elevated temperature (e.g., as would be generated by reactions of gases in a described device or reactions of gases in contact with a reaction section of a piston assembly of a described device). Additionally, or alternatively, components of sealing ring assembly 100 may be exposed to temperatures that affect durability and operational lifetimes of one or more components. Accordingly, components of sealing ring assembly 100 may be formed of materials to ensure overall operational utility of sealing ring assembly for a target lifetime. For example, each of segments 104 and other segments 108 may be comprised of graphite while expander ring 102 is comprised of a metal, or alloy, that is capable of maintaining structural integrity and maintain a desired spring constant for a target operational lifetime such that expander ring 102 does not experience stress relaxation or eventual failure for the target operational lifetime of sealing ring assembly 100.

[0079] In some embodiments, one or more components forming sealing ring assembly 100 ring may be constructed of a material with a relatively high thermal conductivity. For example, where sealing ring assembly 100 contacts a bore of a cylinder along which sealing ring assembly 100 is axially translated, the cylinder may be one or more of actively or passively cooled on an outer surface (e.g., by a liquid cooling jacket or by air cooled fins) while reactions of gases propagate a high pressure region towards one or more of the bore or an axially top portion of sealing ring assembly 100. Sealing ring assembly 100 in this arrangement may, in some embodiments, be exposed to additional elevated temperature reaction gases from a reaction section of a piston assembly that is axially displaced from sealing ring assembly 100 (e.g., to cause one or more segments to radially expand outwards to contact the bore of the cylinder). Accordingly, a radially inward region between segments 104 and other segments 108 that is in contact with a radially inward surface of expander ring 102 may start at a lower temperature which is then elevated over the course of operation of the described piston assembly.

[0080] Considering the cooling to be applied to the cylinder along with the propagation of gases from a reaction section, expander ring 102 may be in contact with sealing ring segments of sealing ring assembly 100 that have varying or different temperatures throughout different operational cycles. Where gas of an elevated temperature reaches radially behind expander ring 102, thermal energy from this gas flows through a radial width of expanderring 102 and then radially outward through each contacting ring segment of sealing ring assembly 100. In the event the ring segments are at different, or varying, temperatures, expander ring 102 may ultimately reach an equilibrium temperature that is between that of the gas and that of segments of sealing ring assembly 100 (e.g., as modified based on various cooled areas of the bore of the cylinder). In some embodiments, the equilibrium temperature of expander ring 102 is below a temperature threshold at which material forming expander ring 102 experiences thermal damage such as stress relaxation or other material fatigue that would reduce the operational lifetime of expander ring 102 (e.g., prevent expander ring from continuing to impart a radially outward force on segments of sealing ring assembly 100). For example, expander ring 102 may be constructed of a high-strength, high-temperature superalloy (e.g., one or more of nickel-iron or nickel -chromium alloys).

[0081] As shown in FIG. 1, other segments 108 have varying axial thickness between radial ends of other segment 108. For example, a central portion of other segments 108 are axially thicker than stepped surfaces 110 of respective radial ends. The depicted varying thickness assists with maintaining a target contact area between radially outward surfaces 106, adjacent outward surfaces 120, and, for example, a cylinder bore. Additionally, this varying thickness, and corresponding varying contact surface area, enables sealing ring assembly 100 to achieve a target rate of radial wear of the segments forming sealing ring assembly 100. In some embodiments, the target rate of wear corresponds to ring segments 104 and other ring segments 108 having one or more of the same, relatively larger, or relatively smaller axial thicknesses. Additionally, or alternatively, any suitable combination of segment features, segment cross sections, or contact surface profiles (e.g., as at least partially defined by axial thicknesses of different segments) may be imparted on sealing ring assembly 100 to achieve a target rate of wear and to maintain a desired contact surface area for a target operational lifetime.

[0082] As shown in FIG. 1, sealing ring assembly 100 includes a same number of ring segments 104 as the depicted number of other ring segments 108. For example, there are four of ring segments 104 shown along with four of other ring segments 108. In some embodiments, there may be any suitable number of at least one of ring segments 104 or other ring segments 108 (e.g., 2, 4, or 6 of each respective ring segment) depending on the specific geometry and target wear rate desired to be achieved by sealing ring assembly 100. In some embodiments, expander ring 102 may comprise a pair of separate expanders. For example, expander ring 102 may be replaced by two or more axially stacked expanders that populate each of circumferential grooves 118. Additionally, or alternatively, expander ring 102 maybe replaced by two or more axially displaced expanders in separate axially displaced iterations of circumferential grooves 118. In some embodiments, where expander ring 102 is replaced with two or more expander beams, each expander beam may be clocked relative to each other such that each segment of sealing ring assembly 100 is imparted a suitable radially outward force from one or more of the two or more expander beams to maintain a target contact area between radially outward surfaces 106, adjacent outward surfaces 120, and a bore of a cylinder.

[0083] In some embodiments, where overlapping expander rings are incorporated into, for example, sealing ring assembly 100, a region of radial overlap may extend around the entire circumference of sealing ring assembly 100 (e.g., along circumferential grooves 118).Alternatively, the region of radial overlap may cover only a portion of the radially inner circumferential surface of sealing ring assembly 100. In cases where the radial overlap covers a majority of the circumference, a radial protrusion from expander ring 102 may form a significant portion of a radially outward expansion force on the various segments of sealing ring assembly 100. A radial profile of said protrusion may be profiled in a radial direction to create uniform radial pressure around the radially inner circumferential surface of sealing ring assembly 100.

[0084] In some embodiments, an overlap region between overlapping expander rings may constitute less than all of the radially inner circumferential surface of sealing ring assembly 100. Accordingly, this overlap region may not result in beam bending of one or more portions of expander ring 102 and may not result in application of radial force to the radially inner circumferential surface of sealing ring assembly 100. For example, expander ring 102, or stacked portions thereof, may incorporate radial features, or pads, in some portions that are radially wider than other portions of expander ring 102. These radial features, or pads, may include more material used to form expander ring 102 and, accordingly, are relatively stiffer than portions of expander ring 102 that lack these radial features, or pads. Between these radial features, or pads, may be beam elements that are susceptible to radial deflection so as to impart a radially outward force on the radially inner circumferential surface of sealing ring assembly 100.

[0085] Although not shown in FIG. 1, expander ring 102 may, in some embodiments, include at least one clocking feature that extends from a radially outward surface of expander ring 102 in a portion of circumferential groove 118 of one of ring segments 104. The at least one clocking feature may be radially opposite from side gap 114 between disconnected ends 116. Additionally, or alternatively, disconnected ends 116 may be installed in, interface with,or otherwise embedded in a portion of circumferential groove of a radially opposite one of ring segments 104. Extending radially inward from expander ring 102 is radial feature 122. Radial feature 122 may, in some embodiments, be a protrusion, a bump, or any suitable feature for reducing one or more of stress or strain experienced by a radially inward surface of expander ring 102. For example, the described at least one clocking feature (not shown in FIG. 1) may be a protrusion extending radially outward from a radially outward surface of expander ring 102 which imparts one or more of stress or strain on radially extending beams of expander ring 102 and radial feature 122 reduces stress on the radially extending beams of expander ring 102 when expander ring 102 is compressed to provide outward radial tension (e.g., expanding radially outward).

[0086] Suitable expander rings for use in the assemblies of this disclosure may include various cross-sectional shapes for engagement with segment segments to axially constrain the expander rings described herein relative to features, or circumferential grooves, of sealing ring segments of this disclosure. For example, FIGS, 2A-2E illustrate five different examples of cross-sectional geometries with utility corresponding to the functional effects described herein. FIG. 2A illustrates cross-sectional view 200A of sealing ring segment 202A including expander ring section 204A, in accordance with some embodiments of the disclosure. Cross-sectional view 200A corresponds to a cross-section of one or more of other segments 108 with an example portion of expander ring 102 (e.g., as illustrated by expander ring section 204A) accommodated by a corresponding portion of a respective iteration of circumferential groove 118. Expander ring section 204A is arranged between ring protrusions 206. Ring protrusions 206 extend radially inward from sealing ring segment 202 A when arranged as part of one of other segments 108 of FIG. 1. Expander ring section 204A is configured to impart a radially outward force (e.g., from left to right in FIG. 2A) on sealing ring segment 202A (e.g., when sealing ring segment 202A is arranged in a circumferential groove of a piston assembly arranged to axially translate along a bore of a cylinder of a device).

[0087] FIG. 2B illustrates cross-sectional view 200B of sealing ring segment 202B including expander ring section 204B, in accordance with some embodiments of the disclosure. Cross-sectional view 200B corresponds to a cross-section of one or more of other segments 108 with an example portion of expander ring 102 (e.g., as illustrated by expander ring section 204B) accommodated by a corresponding portion of a respective iteration of circumferential groove 118. Expander ring section 204B includes radial protrusion 208 and axial protrusions 210. Radial protrusion 208 and axial protrusions 210 collectively causeexpander ring section 204B to include a T-shaped cross-sectional geometry. Axial protrusions 210 extend axially towards opposite axial surfaces of sealing ring segment 202B. Radial protrusion 208 extends radially inward towards a radially outward surface of sealing ring segment 202B (e.g., when sealing ring segment 202B is arranged in a circumferential groove of a piston assembly arranged to axially translate along a bore of a cylinder of a device). Radial surfaces (e.g., the radially inward surfaces contacting the ring segment as expanded outward based on expansion of the overall expander at least in part by the radially outward surface shown) of each of axial protrusions 210 and radial protrusion 208 are configured to impart a radially outward force (e.g., from left to right in FIG. 2B) on sealing ring segment 202B. Additionally, or alternatively, axial protrusions 210 may be configured to impart axial stability along a radially inward surface of sealing ring segment 202B to enable one or more of consistent or uniform contact between a surface area of a radially outward surface of sealing ring segment 202B and a bore of a cylinder.

[0088] FIG. 2C illustrates cross-sectional view 200C of sealing ring segment 202C interfacing with radial channel 212 of expander ring section 204C, in accordance with some embodiments of the disclosure. Cross-sectional view 200C corresponds to a cross-section of one or more of other segments 108 with an example portion of expander ring 102 (e.g., as illustrated by expander ring section 204C) interfacing with a radially inward surface of one or more of other segments 108. Radial channel 212 is arranged to contact axially opposite surfaces of sealing ring segment 202C. Radial channel 212 includes radial walls 214 that extend towards a radially outward surface of sealing ring segment 202C and extend along opposite axial surfaces of sealing ring segment 202C. Radial walls 214 cause expander ring section 204C to include a U-shaped cross-sectional geometry. Seated in a recess of sealing ring segment 202C is a portion of other ring segment 216. Other ring segment 216 corresponds to a portion of ring segments 104 of FIG. 1 that include a complementary stepped portion for interfacing with a stepped portion of other ring segments 108 of FIG. 1. In some embodiments, radial walls 214 may be embedded in graphite of sealing ring segment 202C such that axially outward surfaces of radial walls 214 are contacted, or at least nearly contacted, by graphite.

[0089] FIG. 2D illustrates cross-sectional view 200D of sealing ring segment 202D with expander ring section 204D interfacing with radial protrusion 220 of sealing ring segment 202D, in accordance with some embodiments of the disclosure. Cross-sectional view 200D corresponds to a cross-section of one or more of other segments 108 with an example portion of expander ring 102 (e.g., as illustrated by expander ring section 204D) interfacing with aradially inward surface of one or more of other segments 108. A U-shaped channel is formed between radial walls 218 of expander ring section 204D. Each of radial walls 218 is arranged to contact a respective axially opposite surface of sealing ring segment 202C. Radial walls 218 that extend towards a radially outward surface of sealing ring segment 202D and extend along opposite axial surfaces of sealing ring segment 202D. Radial walls 218 cause expander ring section 204D to include a U-shaped cross-sectional geometry. In some embodiments, radial walls 218 may be embedded in graphite of sealing ring segment 202D such that axially outward surfaces of radial walls 218 are contacted, or at least nearly contacted, by graphite.

[0090] FIG. 2E illustrates cross-sectional view 200E of sealing ring segment 202E with pressure locking feature 226 interfacing with radial vertex 236 of expander ring section 204E, in accordance with some embodiments of the disclosure. Cross-sectional view 200E corresponds to a cross-section of one or more of other segments 108 with an example portion of expander ring 102 (e.g., as illustrated by expander ring section 204E) interfacing with a radially inward surface of one or more of other segments 108. Pressure locking feature 226 is shown in FIG. 2E as a through feature extending from a first axial surface of sealing ring segment 202E to a second axial surface of sealing ring segment 202E and radially inward comer 228 of sealing ring segment 202E (e.g., corresponding to the positioning of radial vertex 220 of expander ring section 204E). In some embodiments, pressure locking feature 226 may not be arranged to interface with radially inward cord 228.

[0091] It should be understood that the primary function is forming a low pressure region between one or more of an axial surface or a radial surface of sealing ring segment 202E and a surface of expander ring section 204E that is configured to, or arranged to, contact the corresponding axial surface or radial surface of sealing ring segment 202E. Preferably, the contact interface including at least an opening for pressure locking feature 226 is of a large enough area to prevent relative axial motion between a surface sealing ring segment 202E and a surface of expander ring section 204E during operation of a device in which these components are installed (e.g., during a apex described herein). In some embodiments, one or more of the openings of pressure locking feature 226 may be arranged on any suitable surface (e.g., the same as or different from those show in FIG. 2E) to achieve the described low pressure region within pressure locking feature 226 (e.g., to draw an expander towards a ring surface).

[0092] Radial vertex 220 of expander ring section 204E drawn to contact radially inward comer 228 based at least in part on a pressure difference between a first pressurized region (e.g., pressurized region 230) in contact with the first axial surface and a second pressurizedregion (e.g., one or more of pressurized regions 232) in contact with a one or more of a radially inward surface or an axially bottom surface of one or more of sealing ring segment 202E or expander ring section 204E. As shown in FIG. 2E, expander ring section 204E includes axial wall 224 and radial wall 222. Radial wall 222 extends towards a radially outward surface of sealing ring segment 202E. Axial wall 224 extends towards an axially top surface of sealing ring segment 202E (e.g., the axial surface of sealing ring segment 202E in contact with pressurized region 230 with through feature outlet portion 234). Radial wall 222 and axial wall 224 collectively cause expander ring section 204E to have an L-shaped cross sectional geometry.

[0093] Through feature outlet portion 234 may, in some embodiments, vent leakage out to a low-pressure boundary behind (e.g., at least axially or at least partially radially) the depicted ring segment to ensure a volume of through feature 226 remains at a pressure relatively lower than surrounding pressurized regions. Through feature outlet portion 234 is configured to contact pressurized region 230 to cause one or more of an axial force or a radial force generated based on a pressure differential between one or more of pressurized region 230 and either of pressurized regions 232 to draw radial vertex 220 of expander ring section 204E to contact radially inward corner 228 of sealing ring segment 202E.

[0094] In some embodiments, radial wall 222 may be configured as an axial constraint based on the described pressure locking caused at least in part based on a pressure differential between one or more of pressurized region 230 and either of pressurized regions 232. As illustrated, radial wall 222 extends radially outward from expander ring 204 and axially overlaps while radially extending along an axial surface of sealing ring segment 202E. At least a portion of mating, or contacting, surfaces between radial wall 222 and sealing ring segment 202E is connected to a pressure boundary within, for example, at least one of through feature outlet portion 234 or pressure locking feature 226. As shown in FIG. 2E, through feature outlet portion 234 includes one or more of a pocket, an indentation, or a to increase an area of at least sealing ring segment 202E that is connected to pressurized region 230.

[0095] FIG. 2E as shown illustrates a configuration where pressure locking feature 226 interfaces with a radially inward corner of expander ring section 204E. In some embodiments, pressure locking feature 226 may interface with other locations, or surfaces, of ring section 204E, such as radial wall 222 in order to form a low pressure region between a surface of a ring segment in contact with a surface of an expander ring with enough area toprevent relative axial motion during operation of a device (e.g., corresponding to the apices described herein).

[0096] FIG. 3A illustrates expander 300A for pressing ring segments (not shown) radially outward, in accordance with some embodiments of the disclosure. Expander 300A corresponds to one or more of expander ring 102 of FIG. 1 and expander ring section 204 A of FIG. 2A. Expander 300A includes radial feature 122 arranged radially inward and radially opposite of feature 304 between expander beams 302. Expander beams 302 radially extend towards each other and end at disconnected ends 116. Disconnected ends 116 remain separated based on the radially outward force corresponding to a spring constant of material used to form expander beams 302 (e.g., the radially outward force being used to pressure sealing ring segment radially outward against a bore of a cylinder). Each of expander beams 302 comprise a first portion with radial width 306A which is radially thicker than a second portion with radial width 306B. The first portion extends from a portion of expander 300 A including both radial feature 122 and feature 304.

[0097] As shown in FIG. 3A, feature 304 extends from a radially outward surface of expander 300 A while radial feature 122 extends from a radially inward surfaces of expander 300 A. Feature 304 may, in some embodiments, be considered a clocking feature that prevents relative azimuthal or radial motion of expander 300A when feature 304 interfaces with a corresponding feature in, for example, a circumferential groove in a radially inward surface of a sealing ring segment. As described in reference to FIG. 1, radial feature 122 may, in some embodiments, be a protrusion, a bump, or any suitable feature for reducing one or more of stress or strain experienced near respective radial bases of expander beams 302 or, more particularly, by a radially inward surface of expander 300 A, or any suitable expander (e.g., including other expanders described herein).

[0098] A radial width along each of expander beams 302 may be varied (e.g., to provide a desired radial forms on radially inner surfaces or features of ring segment described herein) to achieve, for example, a uniform radial force among one or more of a potential plurality of ring segments of a sealing ring assembly. As shown in FIG. 3 A, each of expander beams 302, radial width 306 A reduces to radial width 306B such that each of expander beams 302 may include a progressively radially tapered width or geometry (e.g., such that the radial width reduces between the portion of expander 300A with both radial feature 122 and feature 304 until the portion of expander 300A with disconnected ends 116). In some embodiments, each of expander beams 302 may have a uniform radial width along azimuthal or radial lengths of each of expander beams 302.

[0099] Disconnected ends 116 are shown in FIG. 3 A as being radially wider than radial width 306B. Disconnected ends 116 may be configured to prevent or reduce axial rattling of one or more of expander beams 302 relative to a circumferential groove of one or more ring segments (e.g., circumferential grooves 118). Disconnected ends 116 may include a geometry such as a radially flared feature that prevents gouging, mechanical deformation, scoring, or other forms for material wear of graphite of ring segments receiving disconnected ends 116 (e.g., as shown in FIG. 1 proximate to gap 114) by increasing at least a radial, or azimuthal, contact area between each of disconnected ends 116 and at least a portion of a corresponding feature of a ring segment (e.g., axial surfaces of a circumferential groove embedded in a radially inward surface of a ring segment of this disclosure). For example, disconnected ends 116 may comprise respective pads without sharp edges or comers.Considering expander 300A includes disconnected ends 116, expander 300A may be configured as a split ring expander. Disconnected ends 116 are arranged radially opposite of each of radial feature 122 and feature 304. Disconnected ends 116 may, in some embodiments, include one or more features or geometries configured to interface with angled surfaces of ring segments without imparting mechanical deformation (e.g., gouging) on the angled surfaces).

[0100] FIG. 3B illustrates expander 300B for pressing ring segments (not shown) radially outward with radially extending protrusion 308, in accordance with some embodiments of the disclosure. Expander 300B corresponds to one or more of expander ring 102 of FIG. 1 and expander ring section 204B of FIG. 2B. As shown in FIG. 3B, expander 300B is a split ring expander having disconnected ends 316 at azimuthally distal ends of beams 310. Radially extending protrusion 308 is shown as extending from and along an entire radially outer surface of expander 300B until gap 318 between disconnected ends 316. Disconnected ends 316 and gap 318 are arranged on an azimuthally opposite side of expander 300B from feature 312. Feature 312 is shown in FIG. 3B as a pointed protrusion that extends radially outward from the radially outward surface of the split ring expander and radially extending protrusion 308. Feature 312 may, in some embodiments, be configured as an anti-clocking feature that, when interfacing with a complementary feature of a circumferential groove of a ring segment, prevents relative rotation between expander 300B and the interfacing ring segment. On extending from a radially inward surface of expander 300B is feature 314, which is depicted as an axially extending protrusion, bump, or bulge that reduces one or more of stress or strain that would otherwise be experienced by at least a radially inward surface of expander 300B. The depicted configuration of expander 300B with radially extending protrusion 308 impartsa cross-sectional area, or geometry, for each of beams 310 that corresponds to a T-shaped geometry.

[0101] FIG. 3C illustrates partial expander view 300C, providing a partial view of expander 300B of FIG. 3B, with notch 322 at disconnected end 316 of radially extending protrusion 308 A (corresponding to radially extending protrusion 308 of FIG. 3B), in accordance with some embodiments of the disclosure. Notch 322 is shown in FIG. 3C as being embedded in radial end 320 of radially extending protrusion 308A. Notch 322 may be configured as a radial notch that has an axial height and a radially curved profile as shown in FIG. 3C. Notch 322 may have a complementary opposing notch in a second disconnected end that is radially opposite of disconnected end 316 (e.g., as shown in FIG. 3B such that an expander has a pair of notches). Radially extending protrusion 308A and radial end 320 are radially displaced by distance 324 from radial edge 328 of disconnected end 316. Distance 324 may be based at least in part on one or more of a target radially outward spring force for the expander beam depicted in partial expander view 300C or a radial length of a complementary groove in a ring segment in which radially extending protrusion may be embedded). Notch 322 is configured to impart one or more of a radially outward force or an azimuthally outward force against an end of a slot extending along a radially inward surface a ring segment (e.g., such as other ring segments 108 of FIG. 1 arranged radially adjacent to ring segments 104) to server, for example, as a clocking feature of expander 300B. Angled surface 326 may be any suitable angle to assist with the described installation and function of notch 322 and radially extending protrusion 308 A. In some embodiments, radially extending protrusion 308 A may extend to radial edge 328 of disconnected end 316.

[0102] FIG. 3D illustrates isometric view 300D of expander 330 for pressing ring segments (not shown) radially outward based on radial channel 336 interfacing with a radially inward surface of an example ring segment, in accordance with some embodiments of the disclosure. Expander 330 is a split ring expander with radial gap 338 between flared disconnected ends 340. Disconnected ends 340 include flared channel walls that are configured to prevent gouging, or other similar mechanical deformation, when interfacing with graphite of a ring segment that flared disconnected ends 340 contact (e.g., as shown in FIGS. 2C and 2D). In some embodiments, flared disconnected ends 340 may include at least one radially angled surface corresponding to a radial angle of a wedge-shaped ring segment surface (e.g., radially angled surfaces 408 of FIG. 4A). In some embodiments, disconnected ends 340 may flare radially outward similar to disconnected ends 348 of FIG. 3E. Radial channel 336 is formed between axial wall 332 and axial wall 334. Based on the axial displacement between axialwall 332 and axial wall 334, expander 330 includes a U-shaped cross-sectional area or a U-shaped geometry (e.g., for interfacing with one or more of expander ring section 204C of FIG. 2C or expander ring section 204D of FIG. 2D). Depending on how expander 330 is oriented, or displayed, the U-shaped cross-sectional area or the U-shaped geometry may, in some embodiments, be considered a C-shaped cross-sectional area or a C-shaped geometry (e.g., as shown in FIGS. 2C and 2D).

[0103] FIG. 3E illustrates isometric view 300E of expander 342 for pressing ring segments (not shown) radially outward based on radial extending wall 344 (e.g., a radial flange) interfacing with a radially inward surface of an example ring segment, in accordance with some embodiments of the disclosure. Expander 342 is a split ring expander with radial gap 346 between disconnected ends 348. Disconnected ends 348 are depicted in FIG. 3E as being flared radially outward (e.g., to interface with radially angled surfaces of a ring segment). Expander 342 includes axially extending wall 350 which is arranged perpendicular to radially extending wall 344. Based on relative orientations of axially extending wall 350 and radially extending wall 344, expander 342 includes a L-shaped cross-sectional area or a L-shaped geometry (e.g., for interfacing with one or more of expander ring section 204E of FIG. 2E). Radially extending wall 344 may, in some embodiments, be considered a flange that extends azimuthally from an axial end of expander 342 and around a radially outward surface of one or more of expander 342 or axially extending wall 350. Radially extending wall 344 may, in some embodiments, extend around an entire radially outward surface of expander 342. In some embodiments, radially extending wall 344 does not extend all the way to radial ends of disconnected ends 348 (e.g., as exemplified by FIG. 3C where radially extending protrusion 308A is replaced by radially extending wall 344 on an axial end of the depicted expander beam).

[0104] FIG. 4A illustrates isometric view 400A sealing ring segment 402 including circumferential groove 404 for receiving at least a portion of an expander (not shown), in accordance with some embodiments of the disclosure. Sealing ring segment 402 may, in some embodiments, be formed out of graphite. Circumferential groove 404 is sized and shaped to receive an expander, or split ring expander, of this disclosure. In some embodiments, circumferential groove 404 includes at least one feature for receiving a clocking feature of an expander ring (e.g., as shown in FIG. 4B). Sealing ring segment 402 includes radially outward surface 406. Radially outward surface 406 is configured to contact a bore of a cylinder when arranged in a circumferential groove of, for example, a piston assembly. Radially outward surface 406 is configured to wear in a radial direction accordingto a target wear rate in view of a target operational lifetime of a sealing ring assembly including sealing ring segment 402. For example, an expander arranged within circumferential groove 404 is configured to provide a radially outward force (e.g., based on expansion of beams of the expander) according to a rate of expansion of the expander. As shown in FIG. 4A, circumferential groove 404 is formed, in some embodiments, between a pair of protrusions 422 which extend radially from a radially inward surface of sealing ring segment 402. Additionally, or alternatively, protrusions 422 at least partially form circumferential groove 404 such that circumferential groove 404 is configured to receive at least a portion of the split ring expander. As the expander provides the force, radially outward surface 406 contacts a cylinder bore, thereby forming a seal against the bore of the cylinder, and graphite of radially outward surface 406 begins to wear away.

[0105] Axially and radially displaced from radially outward surface 406 are radially angled surfaces 408. Radially angled surfaces 408 are shown as a pair of surfaces. In some embodiments, any suitable number of angles surfaces may be incorporated into sealing ring segment 402 to achieve radially outward displacement (e.g., as enabled by a radially outward force applied by an expander arranged in circumferential groove 404) at a rate corresponding to a target rate of radial wear of radially outward surface 406. A radial angle defining radially angled surfaces 408 may, in some embodiments, be any suitable angle to achieve radially outward displacement (e.g., as enabled by a radially outward force applied by an expander arranged in circumferential groove 404) at a rate corresponding to a target rate of radial wear of radially outward surface 406. Radially angled surfaces 408 are shown in FIG.4A as at least partially defining a wedge profile of wedge shaped surface 410. Wedge shaped surface 410 is shown as at least one of axially or radially displaced from radially outward surface 406. The angled profile of a radially outward edge of wedge shaped surface 410 (e.g., as defined by radially angled surfaces 408 which, in some embodiments, comprise wedge shaped surface 410) is based on one or more of a wear rate of graphite comprising radially outward surface 406 or spring rate of one or more arms, or beams, of an expander to be arranged within circumferential groove 404. Sealing ring segment 402 also includes pillar 412. Pillar 412 is configured to wear in response to contacting a bore of a cylinder when enough of radially outward surface 406 has worn away resulting in contact between a radially outward surface of pillar 412 and the bore of the cylinder. Pillar 412 is configured to maintain a target contact area between graphite of a sealing ring assembly that includes sealing ring segment 402 and the bore of the cylinder as various surfaces of various ring segments of the sealing ring assembly experience wear during operation.

[0106] FIG. 4B illustrates partial sectional view 400B of sealing ring segment 402 of FIG.4 A with material removed for illustrative purposes to expose segment groove feature 414 (e.g., a notch) that interfaces with feature 304 (e.g., a protrusion) of expander 300A of FIG.3 A, in accordance with some embodiments of the disclosure. Partial sectional view 400B shows feature 304 fitting within, or interfacing with, segment groove feature 414 of circumferential groove 404 to provide an azimuthal constraint and to maintain a relative orientation between expander 300A and sealing ring segment 402. In some embodiments, segment groove feature 414 may comprise one or more of a notch, a pocket, or a recess. As shown in FIG. 4B, feature 304 is a protrusion arranged radially opposite of radial feature 122. Feature 304 is received by segment groove feature 414. In some embodiments, segment groove feature 414 may be a protrusion that extends radially inward to be received between two radially outward protrusions of expander 300A (e.g., where feature 304 comprises a pair of protrusions instead of the depicted single protrusion). Alternatively, segment groove feature 414 may comprise a pair of radially inward protrusions between which feature 304 is received for preventing relative azimuthal movement between expander 300 A and radially inward surface 416 of sealing ring segment 402. A radially outward surface of expander 300A is configured to impart a radially outward force on radially inward surface 416 (e.g., based at least in part on a spring rate of beams of expander 300A). As shown in FIG. 4B, segment groove feature 414 (e.g., a radial notch) is embedded in a surface of circumferential groove 404. Segment groove feature 414 is located radially inward from radially outward surface 406.

[0107] FIG. 4C illustrates view 400C of sealing ring segment 402 of FIG. 4 A including radially angled surfaces 408 interfacing with radial ends 420 of split expander 418, in accordance with some embodiments of the disclosure. As shown in FIG. 4C, split expander 418 includes a pair of opposed split radial ends 420. Radial ends 420 are shown with respective radially flared profiles, or features, that are angled to match a seal wedge angle of radially angled surfaces 408 of sealing ring segment 402. Radially angled surfaces 408 are configured to interface with, or otherwise receive, radial ends 420 so as to constrain relative radial or azimuthal movement between split expander 418 and sealing ring segment 402. In some embodiments, split expander 418 may be modified to include any suitable feature of expanders depicted in FIGS. 3 A-3E in order to interface with and constrain relative movement between split expander 418 and sealing ring segment 402.

[0108] FIG. 5 A illustrates angled view 500A of other ring segment 502 with steps 504 in axial surface 506 that modify a contact area of radially outward surface 508, in accordancewith some embodiments of the disclosure. Other ring segment 502 may, in some embodiments, be formed of graphite. Steps 504 progressively reduce a surface area of radially outward surface 508 from a radial center of axial surface 506 towards radial ends comprising angled surfaces 510. Radially outward surface 508 is configured to contact a bore of a cylinder as an expander of this disclosure imparts a radially outward force against a radially inward surface of a circumferential groove (not shown in FIG. 5 A) embedded in a radially inward surface of other ring segment 502. Angled surfaces 510 are configured to contact, for example, radially angled surfaces 408 of FIG. 4A when other ring segment 502 is arranged to azimuthally contact sealing ring segment 402. The axially top surface shown of at least the radially outward depicted steps 504 may provide a surface for receiving a portion of sealing ring segment 402 comprising radially outward surface 406.

[0109] Top axial surface 512 of other ring segment 502 has an axial thickness that, in some embodiments, is the same as an axial thickness of sealing ring segment 402. Accordingly, steps 504 progressively reduce an axial thickness in one or more of an azimuthal direction or a radial direction of radially outward surface 508. Alternatively, top axial surface 512 may have an axial thickness that is different from (e.g., larger or smaller) an axial thickness of sealing ring segment 402 depending on at least one of a target wear rate of radially outward surface 508 or a target contact area for radially outward surface 508. As shown in FIG. 5A, other ring segment 502 (e.g., a ring segment adjacent to sealing ring segment 402) has a varying axial thickness (e.g., based at least in part on the inclusion of steps 504 relative to top axial surface 512) from one radial, or azimuthal, end of radially outward surface 508 to an opposite radial, or azimuthal end of radially outward surface 508.

[0110] FIG. 5B illustrates partial view 500B of radial end 514 of sealing ring segment 516 with groove 518 in radially inward surface 520 for receiving radial feature of an expander (not shown), in accordance with some embodiments of the disclosure. Radial end 514 corresponds to a view of a radially inward surface of the axially thinnest step 504 of FIG. 5 A. Groove 518 is shown as a slot that is embedded in radially inward surface 520 that extends along radially inward surface 520. Groove 518 may, in some embodiments, be configured to receive a protrusion (e.g., radially extending protrusion 308A of FIG. 3C).

[0111] FIG. 5C illustrates partial view 500C with sealing ring segment 516 with disconnected end 316 of FIG. 3C seated in a groove of a radially inward surface of sealing ring segment 516 (e.g., where the groove corresponds to groove 518 of FIG 5B), in accordance with some embodiments of the disclosure. As shown in FIG. 3C, disconnected end 316 includes a radially extending protrusion with a notch disposed in an end of theradially extending protrusion. When arranged to be seated in the described groove of sealing ring segment 516, the notch is configured to impart one or more of a radially outward force or an azimuthally outward force against an end of the groove (e.g., the slot) extending along the radially inward surface of sealing ring segment 516.

[0112] FIG. 6 A illustrates axially bottom view 600 A of tool 602 for installing sealing ring segments of, for example, the sealing ring assembly of FIG. 1 in a circumferential groove of a piston, in accordance with some embodiments of the disclosure. Tool 602 includes pronged portion 604, curved arms 606, and releasable coupling mechanism 608 (e.g., a pin or a quick release pin). Curved arms 606 are pivotably coupled, at respective ends, to azimuthally opposite ends of pronged portion 604. For example, a pin or joint at coupling interfaces 610 may be utilized to pivotably couple ends of curved arms 606 to opposite ends of pronged portion 604. In some embodiments, one or more of pronged portion 604 or curved arms 606 comprise a metal (e.g., one or more of a steel, a suitable alloy, or machined aluminum).Pronged portion 604 also includes a pair of azimuthally spaced prongs 624 and a pair of azimuthally spaced spring loaded plungers 626. Azimuthally spaced spring loaded plungers 626 are configured to impart a radial force to preload a ring segment against a radially inner surface of azimuthally spaced prongs 624.

[0113] Tool 602 also includes lanyard 612 which is coupled at one end to an axial surface of one of curved arms 606 by fastener 614. Fastener 614 is embedded in an axial surface of one of curved arms 606. At a second end of lanyard 612 is pin ring 616. Pin ring 616 provides a gripping feature for twisting and removing releasable coupling mechanism 608 (e.g., to allow separation of ends of curved arms 606). While releasable coupling mechanism 608 and pin ring 616 provide one example of a releasable coupling mechanism (e.g., a pin or a quick release pin) for quickly securing and releasing the tool, other releasable coupling mechanisms may be used to selectively couple curved arms 606 (or opposing end portions thereof) within the scope of this disclosure. For example, releasable coupling mechanism 608 may include one or more of a clasp, an over-center latch (e.g., a cam latch), a spring-biased detent, a spring-biased clip, a quarter-turn fastener, a magnetic latch, or any other structure configured to releasably retain curved arms 606 in a coupled state and to permit intentional release.

[0114] As shown in FIG. 6 A, each of curved arms 606 include at least one of axial clocking steps 618. In some embodiments, curved arms 606 may not include any of axial clocking steps 618. Each of axial clocking steps 618 are configured to align tool 602 with a radially outward surface of at least one ring segment retainer of a piston land. Axial clocking steps618 cause tool 602 to azimuthally and radially align multiple sealing ring segments with features of various ring segment retainers of piston lands of this disclosure. Azimuthally displaced from axial clocking steps 618 along a radial length of curved arms 606 are axial clocking tabs 620. Axial clocking tabs 620 are configured to prevent axial displacement of tool 602 during installation of at least one ring segment in a circumferential groove of a piston. For example, each of axial clocking tabs 620 are configured, or may be arranged, to contact an axial underside of at least one retainer of a plurality of ring retainers of piston lands of this disclosure. Arranged between axial clocking steps 618 and axial clocking tabs 620 are segment retaining plungers 622. Segment retaining plungers 622 may, in some embodiments, include, or interface with respective axially oriented springs. For example, when one of segment retaining plungers 622 is axially displaced from a seated orientation shown in FIG. 6A, a respective axially oriented spring is stretched and imparts an axial force on a body of the one of segment retaining plungers 622 such that the one of segment retaining plungers is pulled back to the seated orientation shown in FIG. 6A. Each of segment retaining plungers 622 is configured to radially retain at least one ring segment of this disclosure between an axially front land and an axially rear land of piston that together form a circumferential groove.

[0115] FIG. 6B illustrates cross section view 600B of releasable coupling mechanism 608 of tool 602 of FIG. 6A, in accordance with some embodiments of the disclosure. Releasable coupling mechanism 608 may, in some embodiment, be a quick release pin. Coupled to a radially outward extending end of releasable coupling mechanism 608 is pin ring 616. A radially inward extending end of releasable coupling mechanism 608 is embedded between radially layered curved arm ends 628 by extending through coupling holes 630. Arranged towards the radially inward extending end of releasable coupling mechanism 608 is release ball 632. Release ball 632 is configured to radially retain end 634 radially inward of both of curved arm ends 628. Release ball 632 is configured to slide along coupling holes 630 when pin ring 616 is pulled with sufficient force to cause release ball 632 to at least partially compress into a surface of releasable coupling mechanism 608 such that releasable coupling mechanism 608 becomes relatively uniformly cylindrical so as to be pulled out of coupling holes 630 (e.g., allowing curved arm ends to be separated. In some embodiments, end 634 comprises one or more of a taper or chamfer such that a tip of end 634 comprises a diameter smaller than a diameter of each of coupling holes 630 (e.g., for ease of insertion through coupling holes 630).

[0116] FIG. 7 illustrates axially top view 700 of tool 602 of FIG. 6A populated with sealing ring segments of sealing ring assembly 100 of FIG. 1, in accordance with some embodiments of the disclosure. As shown in FIG. 7, sealing ring assembly 100 is axially flipped relative to the orientation depicted in FIG. 1. Each of curved arms 606 includes a plurality of segment retaining plungers 622 in a seated configuration to radially retain the depicted plurality of segments (e.g., in a circumferential groove formed between lands of a piston).

[0117] FIG. 8 A illustrates angled view 800 A of sealing ring segment 402 of FIG. 4 A interfacing with an expander 300A of FIG. 3 A held in place by azimuthally spaced prongs 624 of tool 602 of FIG. 6, in accordance with some embodiments of the disclosure. As shown in FIG. 8 A, azimuthally spaced prongs 624 contact a radially inward surface of both expander 300 A and sealing ring segment 402 while a radially outward surface of sealing ring segment 402 is pressed against a radially inward surface of pronged portion 604 (e.g., pronged portion 604 receives the radially outward surface of sealing ring segment 402). Azimuthally spaced prongs 624 retain expander 300A in a radially inward groove (e.g., circumferential groove 404 of FIG. 4) of sealing ring segment 402.

[0118] Releasable coupling mechanism 608 is shown as retained in one of the separated arm ends 628 of curved arms 606. Releasable coupling mechanism 608 is coupled to pin ring 616. Arm ends 628 are azimuthally, or radially, displaced based on the disengagement of releasable coupling mechanism 608 from a radially inwardly stacked arm end of both of arm ends 628. Curved arms 606 are pivoted about coupling interfaces 610 to displace a first of arm ends 628 from a second of arm ends 628.

[0119] FIG. 8B illustrates view 800B with sealing ring segment 402 of FIG. 4 interfacing with expander 300A of FIG. 3A based on points of contact between azimuthally spaced prongs 624 and spring loaded plungers 626 of FIG. 6 A, in accordance with some embodiments of the disclosure. When radially outward surface 406 of sealing ring segment 402 contacts a radially inward surface of pronged portion 604, spring loaded plungers 626 impart radially inward forces 802 against radially outward 406 such that expander 300A is pressed against azimuthally spaced prongs 624. Radially outward surfaces of azimuthally spaced prongs 624 as a result generate reaction forces 804 against a radially inward surface of expander 300A such that expander 300A is pressed into, or retained in, into a circumferential groove (e.g., a radially inward groove such as circumferential groove 404 of FIG. 4) of sealing ring segment 402. Accordingly, it is understood that spring loaded plungers 626 preload sealing ring segment 402 against azimuthally spaced prongs 624. As shown in FIG.8B, coupling interfaces 610 are arranged azimuthally inward and radially outward of springloaded plungers 626. In some embodiments, coupling interfaces 610 may be arranged at least azimuthally outward of spring loaded plungers 626.

[0120] FIG. 9 A illustrates interface 900 A between azimuthally spaced prongs 624 of FIG.6A and sealing ring segment 402 of FIG. 4 with expander 300A of FIG. 3A, in accordance with some embodiments of the disclosure. As shown in FIG. 9A, azimuthally spaced prongs 624 of pronged portion 604 retain expander 300 A against, or within a groove of, sealing ring segment 402.

[0121] FIG. 9B illustrates interface 900B where azimuthally spaced prongs 624 of FIG. 6 A are azimuthally clocked relative to one of retainers 904 of piston land 906 to arrange sealing ring segment 402 axially behind piston land 906 (e.g., in a circumferential groove of a piston with piston land 906), in accordance with some embodiments of the disclosure. Azimuthally spaced prongs 624 are configured to be azimuthally aligned with at least one of retainers 904. Retainers 904 at least partially defines an axial end, as defined at least in part by piston land 906, of a circumferential groove configured to receive sealing ring segment 402. Radial alignment hole 902 is provided in pronged portion 604 to radially constrain sealing ring segment 402 relative to one or more of piston land 906, one of retainers 904, or a circumferential groove at least partially defined by one or more piston land 906 or at least one of retainers 904.

[0122] FIG. 9C illustrates interface 900C with fastener 908 interfacing with radial alignment hole 902 of pronged portion 604 of FIG. 6, in accordance with some embodiments of the disclosure. When fastener 908 is securing in radial alignment hole 902 as shown in FIG. 9C, sealing ring segment 402 of FIG. 4A and expander 300A of FIG. 3A are radially constrained, and arranged axially rearward, relative to retainer 904. Azimuthally spaced prongs 624 are clocked relative to retainer 904. Additionally, azimuthally spaced prongs 624 can be radially displaced along radial path 910 based at least in part on a radial adjustment of fastener 908 relative to radial alignment hole 902.

[0123] FIG. 10 illustrates side view 1000 of an example range of positions of expander ring 300A of FIG. 3A relative to circumferential groove 1002 of piston 1004 based on the depicted arrangement of tool 602 of FIG. 6 A interfacing with sealing ring segment 402 of FIG. 4A (e.g., as held in place in tool 602 as shown in FIGS. 8B-9C), in accordance with some embodiments of the disclosure. Circumferential groove 1002 is formed between a pair of axially displaced piston lands of piston 1004. Sealing ring segment 402 is azimuthally clocked on one side of circumferential groove 1002 based on the arrangement of tool 602 relative to at least one retainer of at least one of the lands of piston 1004 that formcircumferential groove 1002. Based on the interface between sealing ring segment 402 and expander 300A, expander 300A is seated in circumferential groove 404 of sealing ring segment 402. Expander 300A may be axially displaced along expander ring axial position range 1008 depending on a clamping force imparted on sealing ring segment 402 and expander 300A by prongs of tool 602. Expander ring axial position range 1008 is centered about expander axial position 1006 A. Expander ring axial position range 1008 includes axial top position 1006B and axial bottom position 1006C. Any of axial position 1006A, axial top position 1006B, or axial bottom position 1006C may be a position of expander 300A relative to circumferential groove 1002 during installation of sealing ring segment 402 and expander 300A using tool 602.

[0124] FIG. 11 illustrates view 1100 of multiple of sealing ring segments 402 of FIG. 4 A interfacing with tool 602 of FIG. 6 while arranged in circumferential groove 1002 of piston 1004 of FIG. 10, in accordance with some embodiments of the disclosure. Each of sealing ring segment 402 is radially retained in circumferential groove 1002 based at least in part on the depicted seated arrangement of segment retaining plungers 622 (e.g., axially seated relative to curved arms of tool 602) which contact radially outward surfaces of sealing ring segment 402.

[0125] FIG. 12A illustrates partial view 1200A with an example interface between axial clocking steps 618 of tool 602 of FIG. 6A and steps 504 of other ring segments 502 of FIG. 5, in accordance with some embodiments of the disclosure. Segment retaining plunger 622 is arranged to contact radially outer surface 406 of ring segment 402 of FIG. 4 A to retain ring segment 402 against a surface of a groove of a circumferential groove of a piston (e.g., between retainers or lands forming the circumferential groove or inside the circumferential groove). Arranged adjacent on either lateral side of radially outer surface 406 are a pair of radially outward surfaces 508 of other ring segments 502 of FIG. 5. The shown arm of tool 602 of FIG. 6 includes a pair of axial clocking steps 618 which contact respective steps 504 of the depicted other ring segments. Axial clocking steps 618 align tool 602 with radially outward surfaces of at least one retainer of a piston land while also axially constraining radially outward surfaces 508 of other ring segments 502 of FIG. 5.

[0126] FIG. 12B illustrates perspective view 1200B of the entirety of sealing ring assembly 100 of FIG. 1 arranged in circumferential groove 1002 of piston 1004 of FIG. 10 based on an arrangement of tool 602 of FIG. 6, in accordance with some embodiments of the disclosure. As shown in FIG. 12B, there is at least one of segment retaining plungers 622 radiallyretaining each ring segment of sealing ring assembly 100 within circumferential groove 1002 of piston 1004.

[0127] FIG. 13 illustrates axially bottom view 1300 (e.g., a sectional view through a piston with an axially rear land removed) of an example relative orientation between axial clocking tabs 620 of tool 602 of FIG. 6 and retainers 904 of piston 1004 of this disclosure, in accordance with some embodiments of the disclosure. Shown in FIG. 13 is a ring segment 402 of FIG. 4 interfacing with tool 602 so as to be at least radially constrained in a circumferential groove of piston 1004 as at least partially formed by at least one of retainers 904. Axial clocking tabs 620 are shown as contacting an axial underside of a corresponding number of retainers 904. This arrangement prevents axial displacement of tool 602 relative to retainers 904, thereby axially stabilizing ring segment 402 relative to retainers 904. Any suitable number of axial clocking tabs 620 may be utilized to contact against an axially underside of any suitable number of retainers 904 to adequately stabilize, at least axially, ring segment 402 within the described circumferential groove of piston 1004 that is at least partially formed, or defined, by retainers 904. Remaining ring segments of a sealing ring assembly including ring segment 402 (e.g., segments 104 and other segments 108 of FIG. 1) may, in some embodiments, be placed relative to ring segment 402 axially rearward of retainers 804. Each subsequent ring segment may be installed after depressing the shown respective axial ends of segment retaining plungers 622 towards an axially forward surface of tool 602 and sliding the corresponding ring segment radially behind each respective depressed segment retaining plunger 622. Thereafter, each respective segment retaining plunger may be released and returns to an initial position (e.g., based on tension released from an axially oriented spring) thereby constraining respective installed ring segments radially in, for example, circumferential groove 1002 of piston 1004 of FIG. 10.

[0128] FIG. 14 illustrates side view 1400 of radial contact sleeve 1402 of a cylinder assembly (not shown) interfacing with radially outward surface 1404 of installed sealing ring assembly 100 of FIG. 1 based on an arrangement of tool 602 of FIG. 6 relative to retainers of piston 1004, in accordance with some embodiments of the disclosure. Radially outward surface 1404 of installed sealing ring assembly 100 (e.g., the collective radially outward surface of each ring segment used to collectively form sealing ring assembly 100) is shown as being positive radially inward of each shown example of segment retaining plungers 622 such that each depicted segment is radially retained by at least one of the shown segment retaining plungers 622. Radial contact sleeve 1402 is shown as circumferentially encompassing, and at least partially axially covering, radially outward surface 1404 of sealingring assembly 100. Radial contact sleeve 1402 may, in some embodiments, be a cylindrical flange that can be axially displaced relative to a cylinder assembly with a bore along with piston 1004 is configured to axially translate. Radial contact sleeve 1402 holds sealing ring assembly 100 in a compressed state (e.g., considering sealing ring assembly includes an expander ring that imparts a radially outward force on each of a plurality of segments forming sealing ring assembly 100). Once radial contact sleeve 1402 is axially translated to cover at least a portion of radially outward surface 1404, tool 602 can be removed from retainers of piston 1004.

[0129] FIG. 15 depicts flow chart 1500 representing an illustrative process for using a tool of this disclosure to install a sealing ring assembly of this disclosure in a circumferential groove of a piston, in accordance with some embodiments of the disclosure. At process block 1502, radial ends of curved arms of an installation tool are separated, wherein the installation tool interfaces with an assembly that comprises a self-lubricating ring segment, and an expander ring. At process block 1504, the graphite ring segment is arranged in a circumferential groove formed between an axially front land of a piston and an axially rear land of the piston, wherein a pair of prongs of the installation tool is radially clocked relative to a ring retainer of the axially front land of the piston. At process block 1506, the radial ends of the curved arms of the installation tool are articulated until the radial ends contact each other. At process block 1508, at least one plunger of at least one curved arm of the installation tool is pulled. At process block 1510, at least one other ring segment is arranged in the circumferential groove. At process block 1512, the at least one plunger is released such that the at least one plunger radially abuts a radially outward surface of the at least one other ring segment. At process block 1514, a radial contact surface of a cylinder assembly is axially displaced over an axial end of the graphite ring segment and the at least one other ring segment to radially retain the self-lubricating ring segment and the at least one other ring segment. At process block 1516, the radial ends of the curved arms of the installation tool are separated. At process block 1518, the installation tool is removed from the graphite ring segment and the expander ring.

[0130] FIG. 16 depicts shows a cross-sectional view of a portion of illustrative cylinder assembly 1600 having a sealing ring assembly configured to expand radially outward to seal against a bore of a cylinder, in accordance with some embodiments of the present disclosure. As illustrated, piston and cylinder assembly 1600 includes sealing ring assembly 1620 comprising expander ring 1690 (e.g., expander 300A of FIG. 3A or any suitable expander including combinations of features of expanders of this disclosure), cylinder 1660 mayinclude bore 1662, which is the inner cylindrical surface in which piston assembly 1610 travels.

[0131] Piston assembly 1610 includes piston 1626, which includes sealing ring groove 1622 defined at least in part by axially front land 1692 and axially rear land 1694, in which sealing ring assembly 1620 is configured to ride. Axially front land 1692 may, in some embodiments, include at least one sealing ring retainer (e.g., one or more of retainers 904 of FIG. 9B). As piston assembly 1610 translates along axial direction (e.g., indicated by direction 1680) during a stroke of a cycle, in cylinder 1660, the gas pressure in high-pressure region 1650 may change (high-pressure region 1650 may be closed with a cylinder head or an opposing piston). For example, as piston assembly 1610 moves to the left in FIG. 16, the pressure in high-pressure region may increase. Low-pressure region 1670, located to the rear of sealing ring assembly 1620 may be at a gas pressure below the pressure of high-pressure region 1650 for at least some, if not most, of a stroke or cycle of piston and cylinder assembly 1600. The pressure ranges in high-pressure region 1650 and low-pressure region 1670 may be any suitable ranges (e.g., sub-atmospheric pressure to well over 250 bar), and may depend on compression ratio, breathing details (e.g., boost pressure, pressure waves, port timing), losses, thermochemical properties of gases, and reaction thereof. Accordingly, the sealing ring assemblies described herein may be used to seal any suitable high-pressure region and low-pressure region, having any suitable pressure ranges. For example, in some embodiments, low-pressure region 1670 may interact flow- wise with intake or exhaust ducting, and be maintained relatively near pressure in the ducting.

[0132] In some embodiments, low-pressure region 1670 may open to intake breathing ports, and may be at a pressure near to or strongly affected by (e.g., on average) an intake pressure (e.g., a boost pressure). In a further illustrative example, low-pressure region 1670 may open to exhaust breathing ports, and may be at a pressure near to or strongly affected by (e.g., on average) an exhaust pressure. In accordance with the present disclosure, sealing ring assemblies may be used to seal high-pressure regions from low-pressure regions for at least part of a stroke or cycle of a piston and cylinder assembly. It will be understood that the "front" of sealing ring assembly 1620 refers to the face axially nearest high-pressure region 1650, and the "rear" of sealing ring assembly 1620 refers to the face axially nearest low-pressure region 1670.

[0133] It will be understood that unless otherwise specified, all pressures referred to herein are in absolute units (e.g., not gage or relative). It will also be understood that high-pressure and low-pressure may refer to transient pressure states of a piston and cylinder device. Forexample, referencing a thermodynamic cycle, the high-pressure side of a sealing ring assembly may have a pressure greater than a low-pressure side of the sealing ring assembly for most of the engine cycle (e.g., except possibly during breathing or near-breathing portions of the cycle). Accordingly, high-pressure and low-pressure are relative and depend on the conditions of the gas being sealed. For example, a sealing ring assembly may be used to seal a high pressure and a low-pressure region, each operating in any suitable pressure range. It will also be understood that a sealing ring assembly may seal differently at different positions in a cycle. It will be further understood that a low-pressure region may include a pressure greater than a pressure of a high-pressure region for some of a piston stroke or cycle of a piston and cylinder assembly. For example, a sealing ring assembly may always seal a high-pressure region from a low-pressure region.

[0134] In some embodiments, a sealing ring assembly may seal a high-pressure region from a low-pressure region as long as the pressure in the high-pressure region is greater than the pressure in the low-pressure region. In a further example, a sealing ring assembly may seal a high-pressure region from a low-pressure region as long as the pressure in the high-pressure region is greater than the pressure in the low-pressure region, and conversely, seal a low-pressure region from a high-pressure region as long as the pressure in the low-pressure region is greater than the pressure in the high-pressure region.

[0135] In some embodiments, sealing ring assembly 1620 may deposit material on bore 1662 of cylinder 1660 (e.g., include a self-lubricating material, which may include graphite). Deposited material may lubricate the bore-to-sealing ring assembly interface between bore 1662 and sealing ring assembly 1620 (e.g., provide a dry lubricant). Accordingly, in some embodiments, piston and cylinder assembly 1600 may operate without liquid for lubrication (e.g., oil). In some embodiments, piston 1626 may be an open-faced piston. For example, piston 1626 may include openings, cutouts, or other fluid paths from high-pressure region 1650 to ring groove 1622. Accordingly, in some embodiments employing an open-faced piston, the radially inward surfaces (e.g., referencing radial direction 1682 in FIG. 16) of sealing ring assembly 1620 may be exposed to gas pressure of high-pressure region 1650.

[0136] FIG. 17 illustrates device 1700 including sealing ring assemblies of this disclosure installed in circumferential grooves of pistons of device 1700, in accordance with some embodiments of the disclosure. The illustration depicted in FIG. 17 is a cross-sectional view of illustrative device 1700 (e.g., a generator or a linear generator) having two free-piston assemblies 1710 and 1720 (also referred to as translators herein), in accordance with some embodiments of the present disclosure. For example, device 1700 may be a linear generatorconfigured to generate electric power based on a fuel input. Additionally, or alternatively, any or all of sealing ring assemblies 1712, 1722, 1781, and 1786 may include any suitable sealing ring assembly architecture (e.g., any suitable combination of features from one or more of sealing ring assembly 100 of FIG. 1 or sealing ring assembly 1620 of FIG. 16), or any other sealing ring assembly of the present disclosure, for example.

[0137] In some embodiments, device 1700 may include linear electromagnetic machines 1750 and 1755 to convert between kinetic energy of respective free-piston assemblies 1710 and 1720 (e.g., including one or more features of piston 1004 of the preceding figures) and electrical energy. In some embodiments, device 1700 may include gas regions 1760 and 1762, which may, for example, be at a relatively lower pressure than gas region 1770 (e.g., a high-pressure region) for at least some, if not most, of a cycle (e.g., a power cycle, or an air compression cycle). For example, gas regions 1760 and 1762 (e.g., low-pressure regions) may be open to respective breathing ducting (e.g., an intake manifold, an intake system, an exhaust manifold, an exhaust system). To illustrate, breathing ports 1734 and 1735 are configured to provide reactants to, and remove exhaust from, bore 1732 of cylinder 1730. In a further example, gas regions 1760 and 1762 may be vented to atmosphere (e.g., be at about 1.01 bar absolute pressure). In some embodiments, device 1700 may include gas springs 1780 and 1785, which may be used to store and release energy during a cycle in the form of compressed gas (e.g., a driver section). For example, free-piston assemblies 1710 and 1720 may each include respective pistons 1782 and 1787, having grooves for respective sealing ring assemblies 1781 and 1786, to seal respective gas regions 1783 and 1788 (e.g., high-pressure regions) from respective gas regions 1784 and 1789 (e.g., low-pressure regions).

[0138] Cylinder 1730 may include bore 1732, centered about axis 1772. In some embodiments, free-piston assemblies 1710 and 1720 may translate along axis 1772, within bore 1732, allowing gas region 1770 to compress and expand. For example, gas region 1770 may be at relatively high pressure as compared to gas region 1760 for at least some of a stroke of free-piston assemblies 1710 and 1720 (e.g., which may translate along axis 1772 in opposed piston synchronization). Sealing ring assemblies 1712 and 1722 may seal gas region 1770 from respective gas regions 1760 and 1762 within bore 1732. In some embodiments, free-piston assemblies 1710 and 1720 may include respective pistons 1714 and 1724 (e.g., piston 1004 or any suitable variant of piston 1004 from the preceding figures), and respective sealing ring assemblies 1712 and 1722 which may be arranged in respective corresponding grooves of pistons 1714 and 1724. It will be understood that gas regions 1760 and 1762, and gas region 1770, may change volume as free-piston assemblies 1710 and 1720 move or areotherwise positioned at different locations along axis 1772. The portions of respective sealing ring assemblies 1712 and 1722 nearest gas region 1770 are each termed the front, and the portion of sealing ring assemblies 1712 and 1722 nearest respective gas regions 1760 and 1762 are each termed the rear. Sealing ring assemblies 1712 and 1722 may each include a high-pressure boundary, which may each depend on a pressure in gas region 1770. For example, a high-pressure boundary of sealing ring assembly 1712 may be open to gas region 1770 (e.g., coupled by one or more orifices, or other opening), and have a corresponding pressure the same as (e.g., if gas from gas region 1770 is unthrottled in the sealing ring assembly), or less than (e.g., if gas from gas region 1770 is throttled in the sealing ring assembly), the pressure of gas region 1770. Sealing ring assemblies 1712 and 1722 may each include a low-pressure boundary, which may depend on a gas pressure in respective gas regions 1760 and 1762. For example, a low-pressure boundary of sealing ring assembly 1712 may be open to gas region 1760 and have a corresponding pressure about the same as the pressure of gas region 1760.

[0139] In some embodiments, pistons 1714 and 1724 may each include one or more grooves into which one or more respective sealing ring assemblies may be arranged. For example, as shown in FIG. 17, pistons 1714 and 1724 may each include one groove, into which sealing ring assembly 1712 and sealing ring assembly 1722 may be installed, respectively. In a further example, although not shown in FIG. 17, one or more of piston 1714 or piston 1724 may include two grooves, in which two respective sealing ring assemblies may be installed. In a further example, one or more of piston 1714 or piston 1724 may include two grooves, a first of sealing ring assembly 1712 or sealing ring assembly 1722, and a second of sealing ring assembly 1712 or sealing ring assembly 1722 (not shown), arranged to one or more of axially rearward or radially inward of the first of sealing ring assembly 1712 or sealing ring assembly 1722. Additionally, or alternatively, a front of one of the installed sealing ring assemblies may be axially nearer to gas region 1760, thereby sealing pressure in gas region 1760 to pressure between the two sealing ring assemblies (e.g., which may be less than pressure in gas region 1770). Accordingly, a sealing ring assembly may be used to seal any suitable high pressure and low-pressure regions from each other.

[0140] In some embodiments, free-piston assemblies 1710 and 1720 may include respective magnet sections 1751 and 1756, which interact with respective stators 1752 and 1757 to form respective linear electromagnetic machines 1750 and 1755. For example, as free-piston assembly 1710 translates along axis 1772 (e.g., during a stroke of an engine cycle), magnet section 1751 may induce current in windings of stator 1752. Further, current may besupplied to respective phase windings of stator 1752 to generate an electromagnetic force on free-piston assembly 1710 (e.g., to effect motion of free-piston assembly 1710).

[0141] In some embodiments, pistons 1714 and 1724, sealing ring assemblies 1712 and 1722, and cylinder 1730 may be considered a piston and cylinder assembly. In some embodiments, device 1700 may be an engine, an air compressor, any other suitable device having a piston and cylinder assembly, or any combination thereof. In some embodiments, device 1700 need not include two free-piston assemblies. For example, cylinder 1730 could be closed (e.g., with a cylinder head), and free-piston assembly 1710 alone may translate along axis 1772.

[0142] In some embodiments, the disclosure is directed to a method of installing a sealing ring assembly in a circumferential groove of a device, the method comprising:providing sealing ring installation tool, the sealing ring installation tool comprising:a pronged portion comprising a pair of azimuthally spaced prongs, a pair of azimuthally spaced spring loaded plungers embedded in the pronged portion,a pair of curved arms,a respective plurality of azimuthally spaced segment retaining plungers embedded in each curved arm of the pair of curved arms, anda release pin;pulling the release pin out of an interlocked portion of the pair of curved arms, wherein the interlocked portion is arranged radially opposite of the pronged portion;displacing respective unlocked ends of the pair of curved arms radially away from each other based on pivotable couplings between respective pivotable ends of the curved arms and respective radially opposite ends of the pronged portion;providing a graphite ring segment with an expander ring embedded in a groove of the graphite ring segment;arranging the expander ring embedded in the groove of the graphite ring segment between the pair of azimuthally spaced prongs and the pair of azimuthally spaced spring loaded plungers such that a sealing surface of the graphite ring segment contacts each of the pair of azimuthally spaced spring loaded plungers;feeding a first end of the expander ring between a pair of adjacent azimuthally spaced retainers extending from an axially front land of a piston assembly;applying a force to a second end of the expander ring to radially displace the second end from the first end;manipulating the second end of the expanding ring axially below a plurality of azimuthally spaced retained of the piston assembly;rotationally translating the unlocked ends of the pair of curved arms towards each other;inserting the release pin into an overlapping portion of the pair of curved arms when the unlocked ends of the pair of curved arms contact each other;axially displacing an azimuthally spaced segment retaining plunger of one of the pair of curved arms;inserting at least one other ring segment between the axially front land of the piston assembly and an axially rear land such that the at least one other ring segment accommodates the expander ring in a groove of the at least one other ring segment;pressing the azimuthally spaced segment retaining plunger of the one of the pair of curved arms such that the azimuthally spaced segment retaining plunger abuts a radially outward surface of the at least one other ring segment;axially displacing at least one other azimuthally spaced segment retaining plunger of at least one of the pair of curved arms;inserting at least one intermediate ring segment between the graphite ring segment and the at least one other ring segment;pressing the at least one other azimuthally spaced segment retaining plunger such that the at least one other azimuthally spaced segment retaining plunger abuts a radially outward surface of the at least one intermediate ring segment;axially displacing a radial contact surface of a cylinder assembly over an axial end of the graphite ring segment, the at least one other ring segment, and the at least one intermediate ring segment;pulling the release pin out of the interlocked portion of the pair of curved arms; displacing respective unlocked ends of the pair of curved arms radially away from each other; andremoving the sealing ring installation tool from the graphite ring segment, the at least one other ring segment, and the at least one intermediate ring segment such that the expander radially displaces the graphite ring segment, the at least one other ring segment, and the at least one intermediate ring segment outward against a radially inward surface of the radial contact surface.

[0143] The embodiments discussed above are intended to be illustrative and not limiting. One skilled in the art would appreciate that the actions of the processes discussed herein maybe omitted, modified, combined, and / or rearranged, and any additional actions may be performed without departing from the scope of the invention. More generally, the above disclosure is meant to be exemplary and not limiting. Only the claims that follow are meant to set bounds as to what the present disclosure includes. Furthermore, it should be noted that the features and limitations described in any one embodiment may be applied to any other embodiment herein, and flowcharts or examples relating to one embodiment may be combined with any other embodiment in a suitable manner, done in different orders, or done in parallel. In addition, the systems and methods described herein may be performed in real time. It should also be noted that the systems and / or methods described above may be applied to, or used in accordance with, other systems and / or methods.

[0144] While some portions of this disclosure may refer to examples, any such reference is merely to provide context to the instant disclosure and does not form any admission as to what constitutes the state of the art.

[0145] It will be understood that the present disclosure is not limited to the embodiments described herein and can be implemented in the context of any suitable system. In some suitable embodiments, the present disclosure is applicable to reciprocating engines and compressors. In some embodiments, the present disclosure is applicable to free-piston linear generators, engines, and compressors. In some embodiments, the present disclosure is applicable to combustion and reaction devices such as a reciprocating engine, free-piston engine, and linear generator. In some embodiments, the present disclosure is applicable to non-combustion and non-reaction devices such as reciprocating compressors and free-piston compressors. In some embodiments, the present disclosure is applicable to linear reciprocating devices with driver sections (e.g., gas springs). In some embodiments, the present disclosure is applicable to oil-free reciprocating and free-piston engines and compressors. In some embodiments, the present disclosure is applicable to oil-free free-piston engines with internal or external combustion or reactions. In some embodiments, the present disclosure is applicable to oil-free free-piston engines that operate with compression ignition (e.g., homogeneous charge compression ignition (HCCI), stratified charge compression ignition (SCCI), or other compression ignition), spark ignition, or both. In some embodiments, the present disclosure is applicable to oil-free free-piston engines that operate with gaseous fuels, liquid fuels, or both. In some embodiments, the present disclosure is applicable to linear free-piston engines. In some embodiments, the present disclosure is applicable to engines that can be combustion engines with internal combustion / reaction orany type of heat engine with external heat addition (e.g., from a heat source or external reaction such as combustion).

[0146] The foregoing is merely illustrative of the principles of this disclosure, and various modifications may be made by those skilled in the art without departing from the scope of this disclosure. The above-described embodiments are presented for purposes of illustration and not of limitation. The present disclosure also can take many forms other than those explicitly described herein. Accordingly, it is emphasized that this disclosure is not limited to the explicitly disclosed methods, systems, and apparatuses, but is intended to include variations to and modifications thereof, which are within the spirit of the following claims.

Claims

1. What is claimed is:

1. A sealing ring assembly comprising:a split ring expander; anda self-lubricating ring segment comprising:a radially outward surface for forming a seal against a bore of a cylinder, and a feature configured to constrain at least axial movement of the split ring expander relative to the self-lubricating ring segment, wherein a radially outward surface of the split ring expander is configured to impart a radially outward force on the feature and one or more other ring segments of the sealing ring assembly.

2. The sealing ring assembly of claim 1, wherein:the feature comprises a circumferential groove embedded in a radially inward surface of the self-lubricating ring segment; andthe circumferential groove is configured to receive at least a portion of the split ring expander.

3. The sealing ring assembly of claim 1, wherein the split ring expander comprises at least one feature that extends radially outward.

4. The sealing ring assembly of claim 3, wherein the at least one feature comprises one or more of a wall or a flange.

5. The sealing ring assembly of claim 1, wherein the split ring expander comprises a T-shaped cross-sectional geometry.

6. The sealing ring assembly of claim 1, wherein the split ring expander comprises a L-shaped cross-sectional geometry.

7. The sealing ring assembly of claim 1, wherein the split ring expander comprises a C-shaped cross-sectional geometry.

8. The sealing ring assembly of claim 1, wherein:the feature comprises a pair of protrusions extending radially from a radially inward surface of the self-lubricating ring segment; andthe pair of protrusions at least partially form a circumferential groove configured to receive at least a portion of the split ring expander.

9. The sealing ring assembly of claim 1, wherein the self-lubricating ring segment further comprises a pressure locking feature configured to interface with the split ring expander.

10. The sealing ring assembly of claim 9, wherein the pressure locking feature interfaces with a radially extending feature of the split ring expander.

11. The sealing ring assembly of claim 9, wherein the pressure locking feature comprises a through feature extending from a first axial surface of the self-lubricating ring segment to a second axial surface of the self-lubricating ring segment.

12. The sealing ring assembly of claim 9, wherein:the pressure locking feature connects a first pressurized region to a second pressurized region; anda pressure difference between the first pressurized region and the second pressurized region corresponds to a suction force realized through the pressure locking feature that draws the split ring expander towards an axial surface of the self-lubricating ring segment.

13. The sealing ring assembly of claim 12, wherein the suction force realized through the pressure locking feature is applied to the split ring expander to prevent axial movement of the split ring expander relative to the axial surface of the self-lubricating ring segment.

14. The sealing ring assembly of claim 1, wherein the split ring expander comprises a pair of opposed ends.

15. The sealing ring assembly of claim 14, wherein each end of the pair of opposed ends comprises a respective radially flared feature.

16. The sealing ring assembly of claim 14, wherein each end of the pair of opposed ends comprises a respective portion that is radially wider than a respective azimuthally adjacent portion of the split ring expander.

17. The sealing ring assembly of claim 1, wherein the split ring expander comprises a pair of radially curved beams.

18. The sealing ring assembly of claim 17, wherein each beam of the pair of radially curved beams is radially tapered.

19. The sealing ring assembly of claim 17, wherein:each beam of the pair of radially curved beams comprises a respective opposed end; andeach beam of the pair of radially curved beams comprises a respective tapered profile that narrows each beam of the pair of radially curved beams towards each respective opposed end.

20. The sealing ring assembly of claim 1, wherein the split ring expander comprises a protrusion that extends radially inward from a radially inward surface of the split ring expander.

21. The sealing ring assembly of claim 20, wherein the protrusion is configured to reduce at least one of stress or strain of one or more axial or radial surfaces of the split ring expander.

22. The sealing ring assembly of claim 1, further comprising at least one anti-clocking feature configured to at least one of reduce or prevent one or more of azimuthal or rotational movement of the split ring expander relative to the self-lubricating ring segment.

23. The sealing ring assembly of claim 1, wherein:the split ring expander comprises a protrusion extending from a radially outward surface of the split ring expander; andthe self-lubricating ring segment comprises a notch embedded in a radially inward surface of the self-lubricating ring segment.

24. The sealing ring assembly of claim 23, wherein the notch is configured to receive the protrusion to prevent azimuthal rotation of the split ring expander relative to the selflubricating ring segment.

25. The sealing ring assembly of claim 1, wherein the split ring expander comprises metal.

26. The sealing ring assembly of claim 1, wherein the split ring expander comprises at least one steel.

27. The sealing ring assembly of claim 1, wherein the split ring expander comprises at least one superalloy.

28. The sealing ring assembly of claim 27, wherein the at least one superalloy comprises at least nickel.

29. The sealing ring assembly of claim 1, wherein the self-lubricating ring segment comprises graphite.

30. The sealing ring assembly of claim 1, wherein:the radially outward surface is a first radially outward surface;the self-lubricating ring segment comprises a second radially outward surface; the second radially outward surface is radially inward relative to the first radially outward surface; andthe second radially outward surface is configured to contact a radially adjacent ring segment of the sealing ring assembly.

31. A device comprising:a cylinder assembly comprising a bore;a piston assembly configured to translate axially along the bore during operation of the device; anda sealing ring assembly comprising:a split ring expander; anda self-lubricating ring segment comprising:a radially outward surface for forming a seal against a bore of a cylinder, anda feature configured to constrain at least axial movement of the split ring expander relative to the self-lubricating ring segment, wherein a radially outward surface of the split ring expander is configured to impart a radially outward force on the feature and one or more other ring segments of the sealing ring assembly.

32. The device of claim 31, wherein:the feature comprises a circumferential groove embedded in a radially inward surface of the self-lubricating ring segment; andthe circumferential groove is configured to receive at least a portion of the split ring expander.

33. The device of claim 31, wherein the split ring expander comprises at least one feature that extends radially outward.

34. The device of claim 33, wherein the at least one feature comprises one or more of a wall or a flange.

35. The device of claim 31, wherein the split ring expander comprises a T-shaped cross-sectional geometry.

36. The device of claim 31, wherein the split ring expander comprises a L-shaped cross-sectional geometry.

37. The device of claim 31, wherein the split ring expander comprises a C-shaped cross-sectional geometry.

38. The device of claim 31, wherein:the feature comprises a pair of protrusions extending radially from a radially inward surface of the self-lubricating ring segment; andthe pair of protrusions at least partially form a circumferential groove configured to receive at least a portion of the split ring expander.

39. The device of claim 31, wherein the self-lubricating ring segment further comprises a pressure locking feature configured to interface with the split ring expander.

40. The device of claim 39, wherein the pressure locking feature interfaces with a radially extending feature of the split ring expander.

41. The device of claim 39, wherein the pressure locking feature comprises a through feature extending from a first axial surface of the self-lubricating ring segment to a second axial surface of the self-lubricating ring segment.

42. The device of claim 39, wherein:the pressure locking feature connects a first pressurized region to a second pressurized region; anda pressure difference between the first pressurized region and the second pressurized region corresponds to a suction force realized through the pressure locking feature that draws the split ring expander towards an axial surface of the self-lubricating ring segment.

43. The device of claim 42, wherein the suction force realized through the pressure locking feature is applied to the split ring expander to prevent axial movement of the split ring expander relative to the axial surface of the self-lubricating ring segment.

44. The device of claim 31, wherein the split ring expander comprises a pair of opposed ends.

45. The device of claim 44, wherein each end of the pair of opposed ends comprises a respective radially flared feature.

46. The device of claim 44, wherein each end of the pair of opposed ends comprises a respective portion that is radially wider than a respective azimuthally adjacent portion of the split ring expander.

47. The device of claim 41, wherein the split ring expander comprises a pair of radially curved beams.

48. The device of claim 47, wherein each beam of the pair of radially curved beams is radially tapered.

49. The device of claim 47, wherein:each beam of the pair of radially curved beams comprises a respective opposed end; andeach beam of the pair of radially curved beams comprises a respective tapered profile that narrows each beam of the pair of radially curved beams towards each respective opposed end.

50. The device of claim 31, wherein the split ring expander comprises a protrusion that extends radially inward from a radially inward surface of the split ring expander.

51. The device of claim 50, wherein the protrusion is configured to reduce at least one of stress or strain of one or more axial or radial surfaces of the split ring expander.

52. The device of claim 31, further comprising at least one anti-clocking feature configured to at least one of reduce or prevent one or more of azimuthal or rotational movement of the split ring expander relative to the self-lubricating ring segment.

53. The device of claim 31, wherein:the split ring expander comprises a protrusion extending from a radially outward surface of the split ring expander; andthe self-lubricating ring segment comprises a notch embedded in a radially inward surface of the self-lubricating ring segment.

54. The device of claim 53, wherein the notch is configured to receive the protrusion to prevent azimuthal rotation of the split ring expander relative to the self-lubricating ring segment.

55. The device of claim 31, wherein the split ring expander comprises metal.

56. The device of claim 51, wherein the split ring expander comprises at least one steel.

57. The device of claim 51, wherein the split ring expander comprises at least one superalloy.

58. The device of claim 57, wherein the at least one superalloy comprises at least nickel.

59. The device of claim 51, wherein the self-lubricating ring segment comprises graphite.

60. The device of claim 51, wherein:the radially outward surface is a first radially outward surface;the self-lubricating ring segment comprises a second radially outward surface; the second radially outward surface is radially inward relative to the first radially outward surface; andthe second radially outward surface is configured to contact a radially adjacent ring segment of the sealing ring assembly.

61. A sealing ring assembly comprising:a self-lubricating ring segment comprising:a first feature, anda radially outward surface for forming a seal against a bore of a cylinder; and an expander comprising a second feature and contacting a radially inward surface of the self-lubricating ring segment, wherein:the second feature is configured to engage with the first feature to constrain relative movement between the self-lubricating ring segment and the expander, anda radially outward surface of the expander imparts a radially outward force on the first feature and one or more other ring segments of the sealing ring assembly.

62. The sealing ring assembly of claim 61, wherein:the self-lubricating ring segment further comprises a circumferential groove; and the first feature comprises a notch.

63. The sealing ring assembly of claim 62, wherein the notch is embedded in a surface of the circumferential groove.

64. The sealing ring assembly of claim 61, wherein the self-lubricating ring segment comprises graphite.

65. The sealing ring assembly of claim 61, wherein:the self-lubricating ring segment further comprises a circumferential groove on a radially inward surface of the self-lubricating ring segment; andthe first feature comprises a radial notch embedded in the circumferential groove.

66. The sealing ring assembly of claim 61, wherein the second feature comprises a protrusion.

67. The sealing ring assembly of claim 61, wherein the second feature comprises an antirotation clocking feature.

68. The sealing ring assembly of claim 61, wherein the second feature extends from the radially outward surface of the expander.

69. The sealing ring assembly of claim 61, wherein:the expander comprises a split ring expander; andthe split ring expander comprises a pair of opposed ends, wherein each respective end of the pair of opposed ends comprises a respective feature such that each respective end is radially wider than respective portions of the split ring expander proximate to each respective end.

70. The sealing ring assembly of claim 69, wherein the second feature is arranged on a first radial side of the split ring expander that is radially opposite from a second radial side of the split ring expander that comprises the pair of opposed ends.

71. The sealing ring assembly of claim 61, wherein:the expander comprises a pair of opposed split ends;each respective opposed split end of the pair of opposed split ends comprises a respective radially flared feature; andeach respective radially flared feature is angled to match a seal wedge angle of a corresponding surface of a sealing ring segment configured to interface with each respective radially flared feature.

72. The sealing ring assembly of claim 61, wherein:the expander comprises a split ring expander;the second feature comprises a protrusion that extends radially outward from a radially outward surface of the split ring expander;a pair of disconnected ends of the split ring expander is arranged azimuthally opposite the second feature; anda cross-sectional area of the split ring expander comprises a T-shaped geometry.

73. The sealing ring assembly of claim 72, wherein:the second feature further comprises a pair of radial notches;each respective notch of the pair of radial notches is azimuthally displaced from a respective disconnected end of the pair of disconnected ends;each respective notch is configured to impart one or more of a radially outward force or an azimuthally outward force against an end of a slot extending along a radially inward surface a ring segment arranged radially adjacent to the self-lubricating ring segment; and the slot extending along the radially inward surface is configured to receive the protrusion.

74. The sealing ring assembly of claim 61, wherein:the expander comprises a split ring expander;a pair of disconnected ends of the split ring expander comprise respective radially flared portions; anda cross-sectional area of the split ring expander comprises a U-shaped geometry.

75. The sealing ring assembly of claim 61, wherein:the expander comprises a split ring expander;a flange extends azimuthally, from an axial end of the split ring expander, around an outer surface of the split ring expander; anda cross-sectional area of the split ring expander comprises a L-shaped geometry.

76. The sealing ring assembly of claim 75, further comprising at least one adjacent ring segment, wherein:the at least one other adjacent ring segment comprises:one or more of a self-lubricating material or graphite,a stepped surface configured to contact a radially angled surface of the selflubricating ring segment, anda through feature extending from a first axial surface of the at least one other adjacent ring segment to a second axial surface of the at least one other adjacent ring segment and a radially inward corner; anda vertex of the L-shaped geometry is drawn to contact the radially inward comer based at least in part on a pressure difference between a first pressurized region in contact with the first axial surface and a second pressurized region in contact with a radially inward surface of the L-shaped geometry.

77. The sealing ring assembly of claim 61, wherein the self-lubricating ring segment comprises a wedge shaped surface that is at least one of axially or radially displaced from the radially outward surface.

78. The sealing ring assembly of claim 77, wherein the wedge shaped surface comprises a pair of radially angled surfaces.

79. The sealing ring assembly of claim 78, wherein each respective radial angle of each of angled surface of the pair of radially angled surfaces is based on one or more of a wear rate of one or more of self-lubricating material or graphite comprising the radially outward surface or spring rate of one or more arms of the expander.

80. The sealing ring assembly of claim 78, wherein:the sealing ring assembly further comprises at least one adjacent ring segment; the at least one adjacent ring segment comprises one or more of a self-lubricating material or graphite; andthe at least one adjacent ring segment comprises a stepped surface configured to contact a radially angled surface of the pair of radially angled surfaces.

81. The sealing ring assembly of claim 80, wherein the at least one adjacent ring segment comprises a first axial thickness that is different from a second axial thickness of the selflubricating ring segment.

82. The sealing ring assembly of claim 80, wherein the at least one adjacent ring segment comprises a varying axial thickness from one radial end of the at least one adjacent ring segment to an opposite radial end of the at least one adjacent ring segment.

83. The sealing ring assembly of claim 61, wherein:the self-lubricating ring segment is a first radially outward ring segment;the sealing ring assembly comprises:at least one other radially outward ring segment, andat least one radially inward ring segment configured to contact at least one of a first radial end of the first radially outward ring segment or a second radial end of the at least one other radially outward ring segment; andthe sealing ring assembly further comprises a same number of radially inward ring segments and radially outward ring segments.

84. A device comprising:a cylinder assembly comprising a bore;a piston assembly configured to translate axially along the bore during operation of the device; anda sealing ring assembly comprising:a self-lubricating ring segment comprising:a first feature, anda radially outward surface for forming a seal against a bore of a cylinder; andan expander comprising a second feature and contacting a radially inward surface of the self-lubricating ring segment, wherein:the second feature is configured to engage with the first feature to constrain relative movement between the self-lubricating ring segment and the expander, and a radially outward surface of the expander imparts a radially outward force on the first feature and one or more other ring segments of the sealing ring assembly.

85. The device of claim 84, wherein the piston assembly comprises:a piston face;an axially front land extended from a radially outward portion of the piston face; an axially rear land;a plurality of sealing ring retainers that extend radially outward from the axially front land; anda circumferential groove formed between the axially front land and the axially rear land, wherein the sealing ring assembly is configured to occupy the circumferential groove.

86. The device of claim 84, wherein:the self-lubricating ring segment further comprises a circumferential groove; and the first feature comprises a notch.

87. The device of claim 86, wherein the notch is embedded in a surface of the circumferential groove.

88. The device of claim 84, wherein the self-lubricating ring segment comprises graphite.

89. The device of claim 84, wherein:the self-lubricating ring segment further comprises a circumferential groove on a radially inward surface of the self-lubricating ring segment; andthe first feature comprises a radial notch embedded in the circumferential groove.

90. The device of claim 84, wherein the second feature comprises a protrusion.

91. The device of claim 84, wherein the second feature comprises an anti-rotation clocking feature.

92. The device of claim 84, wherein the second feature extends from the radially outward surface of the expander.

93. The device of claim 84, wherein:the expander comprises a split ring expander; andthe split ring expander comprises a pair of opposed ends, wherein each respective end of the pair of opposed ends comprises a respective feature such that each respective end is radially wider than respective portions of the split ring expander proximate to each respective end.

94. The device of claim 93, wherein the second feature is arranged on a first radial side of the split ring expander that is radially opposite from a second radial side of the split ring expander that comprises the pair of opposed ends.

95. The device of claim 84, wherein:the expander comprises a pair of opposed split ends;each respective opposed split end of the pair of opposed split ends comprises a respective radially flared feature; andeach respective radially flared feature is angled to match a seal wedge angle of a corresponding surface of a sealing ring segment configured to interface with each respective radially flared feature.

96. The device of claim 84, wherein:the expander comprises a split ring expander;the second feature comprises a protrusion that extends radially outward from a radially outward surface of the split ring expander;a pair of disconnected ends of the split ring expander is arranged azimuthally opposite the second feature; anda cross-sectional area of the split ring expander comprises a T-shaped geometry.

97. The device of claim 96, wherein:the second feature further comprises a pair of radial notches;each respective notch of the pair of radial notches is azimuthally displaced from a respective disconnected end of the pair of disconnected ends;each respective notch is configured to impart one or more of a radially outward force or an azimuthally outward force against an end of a slot extending along a radially inward surface a ring segment arranged radially adjacent to the self-lubricating ring segment; and the slot extending along the radially inward surface is configured to receive the protrusion.

98. The device of claim 84, wherein:the expander comprises a split ring expander;a pair of disconnected ends of the split ring expander comprise respective radially flared portions; anda cross-sectional area of the split ring expander comprises a U-shaped geometry.

99. The device of claim 84, wherein:the expander comprises a split ring expander;a flange extends azimuthally, from an axial end of the split ring expander, around an outer surface of the split ring expander; anda cross-sectional area of the split ring expander comprises a L-shaped geometry.

100. The device of claim 99, further comprising at least one adjacent ring segment, wherein:the at least one other adjacent ring segment comprises:one or more of a self-lubricating material or graphite,a stepped surface configured to contact a radially angled surface of the selflubricating ring segment, anda through feature extending from a first axial surface of the at least one other adjacent ring segment to a second axial surface of the at least one other adjacent ring segment and a radially inward corner; anda vertex of the L-shaped geometry is drawn to contact the radially inward comer based at least in part on a pressure difference between a first pressurized region in contact with the first axial surface and a second pressurized region in contact with a radially inward surface of the L-shaped geometry.

101. The device of claim 84, wherein the self-lubricating ring segment comprises a wedge shaped surface that is at least one of axially or radially displaced from the radially outward surface.

102. The device of claim 101, wherein the wedge shaped surface comprises a pair of radially angled surfaces.

103. The device of claim 102, wherein each respective radial angle of each of angled surface of the pair of radially angled surfaces is based on one or more of a wear rate of one or more of a self-lubricating material or graphite comprising the radially outward surface or spring rate of one or more arms of the expander.

104. The device of claim 102, wherein:the sealing ring assembly further comprises at least one adjacent ring segment; the at least one adjacent ring segment comprises one or more of a self-lubricating material or graphite; andthe at least one adjacent ring segment comprises a stepped surface configured to contact a radially angled surface of the pair of radially angled surfaces.

105. The device of claim 104, wherein the at least one adjacent ring segment comprises a first axial thickness that is different from a second axial thickness of the self-lubricating ring segment.

106. The device of claim 104, wherein the at least one adjacent ring segment comprises a varying axial thickness from one radial end of the at least one adjacent ring segment to an opposite radial end of the at least one adjacent ring segment.

107. The device of claim 84, wherein:the self-lubricating ring segment is a first radially outward ring segment;the sealing ring assembly comprises:at least one other radially outward ring segment, andat least one radially inward ring segment configured to contact at least one of a first radial end of the first radially outward ring segment or a second radial end of the at least one other radially outward ring segment; andthe sealing ring assembly further comprises a same number of radially inward ring segments and radially outward ring segments.

108. A sealing ring installation tool comprising:a pronged portion;a pair of curved arms, wherein each respective end of each curved arm of the pair of curved arms is pivotably coupled to azimuthally opposite ends of the pronged portion; anda releasable coupling mechanism.

109. The sealing ring installation tool of claim 108, wherein the releasable coupling mechanism comprises a quick release pin.

110. The sealing ring installation tool of claim 108, wherein the sealing ring installation tool comprises machined aluminum.

111. The sealing ring installation tool of claim 108, further comprising:a lanyard; anda fastener embedded in an axial surface of a curved arm of the pair of curved arms.

112. The sealing ring installation tool of claim 111, wherein:the lanyard is configured to couple the pin to the fastener; andthe fastener secures an end of the lanyard to the axial surface of the curved arm.

113. The sealing ring installation tool of claim 108, wherein the pronged portion is configured to receive a radially outward surface of a ring segment.

114. The sealing ring installation tool of claim 113, wherein the pronged portion comprises:a pair of azimuthally spaced prongs; anda pair of azimuthally spaced spring loaded plungers configured to preload the ring segment against the pair of azimuthally spaced prongs.

115. The sealing ring installation tool of claim 114, wherein the pair of azimuthally spaced prongs is configured to retain an expander within a radially inward groove of the ring segment.

116. The sealing ring installation tool of claim 114, wherein the pair of azimuthally spaced plungers is configured to contact a radially outward surface of the ring segment.

117. The sealing ring installation tool of claim 114, wherein:the pair of azimuthally spaced prongs is configured to be aligned with at least one retainer of a piston; andthe at least one retainer at least partially defines an axial edge of a circumferential groove configured to receive the ring segment.

118. The sealing ring installation tool of claim 115, wherein each curved arm of the pair of curved arms comprises at least one respective axial clocking step configured to align the sealing ring installation tool with a respective radially outward surface of at least one retainer of a piston land.

119. The sealing ring installation tool of claim 115, wherein each curved arm of the pair of curved arms comprises at least one respective axial clocking tab configured to prevent axial displacement of the sealing ring installation tool during installation of at least one ring segment in a circumferential groove of a piston.

120. The sealing ring installation tool of claim 119, wherein the at least one respective axial clocking tab is configured to contact an axial underside of at least one retainer of a plurality of retainers of a piston land.

121. The sealing ring installation tool of claim 108, wherein each curved arm of the pair of curved arms comprises at least one segment retaining plunger.

122. The sealing ring installation tool of claim 121, wherein the at least one segment retaining plunger comprises an axially oriented spring.

123. The sealing ring installation tool of claim 121, wherein the at least one segment retaining plunger is configured to radially retain at least one ring segment between an axially front land of a piston and an axially rear land of a piston in a circumferential groove.

124. A method of installing a sealing ring assembly in a circumferential groove of a device, the method comprising:separating radial ends of curved arms of an installation tool, wherein the installation tool interfaces with an assembly comprising:a self-lubricating ring segment, andan expander ring;arranging the self-lubricating ring segment in a circumferential groove formed between an axially front land of a piston and an axially rear land of the piston, wherein a pair of prongs of the installation tool is radially clocked relative to a ring retainer of the axially front land of the piston;articulating the radial ends of the curved arms of the installation tool until the radial ends contact each other;pulling at least one plunger of at least one curved arm of the installation tool; arranging at least one other ring segment in the circumferential groove; releasing the at least one plunger such that the at least one plunger radially abuts a radially outward surface of the at least one other ring segment;axially displacing a radial contact surface of a cylinder assembly over an axial end of the self-lubricating ring segment and the at least one other ring segment to radially retain the self-lubricating ring segment and the at least one other ring segment;separating the radial ends of the curved arms of the installation tool; and removing the installation tool from the self-lubricating ring segment and the expander ring.

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