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This invention was made with Government support under Contract N00019-21-G-0005, D.O. N00019-23 F-0019 awarded by the United States Navy. The Government has certain rights in this invention.
BACKGROUND OF THE INVENTION
1. Technical Field
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The present disclosure relates to blade outer air seals (BOAS) as used in gas turbine engines in general, and to mounting hardware and structures for BOAS in particular.
2. Background Information
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Certain traditional BOAS mounts include a full hoop structure which allowed the BOAS to be interference fit between a BOAS mount and a vane support to secure the BOAS and allow a positive contact between the BOAS and an aft seal. However, certain BOAS mounts are segmented (i.e., not full hoop in structure), which prevents an interference fit from properly sealing the aft face of the BOAS due to rotation of the BOAS mount from torque exerted on the BOAS mount by the BOAS contact with the aft seal. Traditional mounting systems resist this torque using the full hoop structure of the BOAS mount. There is a need for improved BOAS mounting assemblies and devices.
SUMMARY
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According to a first aspect of the present invention, a gas turbine engine is provided that includes a compressor section, a combustor section, a turbine section, and a blade outer air seal (BOAS) assembly (e.g., a blade outer air seal assembly according to the second aspect of the invention or any embodiments thereof described herein). The turbine section has a rotor that includes a disk and a plurality rotor blades extending radially out from the disk. The BOAS assembly is disposed radially outside the rotor, and includes a BOAS support ring having an aft or downstream external surface (a surface facing in an axially downstream direction), a plurality of BOAS segments disposed radially between the BOAS support ring and the rotor, and a plurality of spring clips engaged with the plurality of BOAS segments and the BOAS support ring. Each spring clip (SC) includes an SC forward segment, an SC aft segment, and an SC engagement segment. The BOAS assembly is disposable in an engaged configuration. In the engaged configuration, the SC forward segments of the spring clips are engaged with a surface of the BOAS support ring, the SC aft segments of the spring clips are engaged with the aft external surface of the BOAS support ring, and the SC engagement segments of the spring clips are engaged with the plurality of BOAS segments. In the engaged configuration, the spring clips are configured to bias the plurality of BOAS segments in an aft axial or downstream direction (e.g., relative to an axis of the engine and/or a flow of gases through the engine).
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In any of the aspects or embodiments described above and herein, the turbine section may include a vane stage disposed downstream of and contiguous with the rotor, and a seal disposed between the vane stage and the plurality of BOAS segments.
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In any of the aspects or embodiments described above and herein, the spring clips may be configured to bias the plurality of BOAS segments toward the seal.
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In any of the aspects or embodiments described above and herein, the bias of the plurality of BOAS segments in the aft axial direction may maintain an engagement of the plurality of BOAS segments with the seal.
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In any of the aspects or embodiments described above and herein, the rotor may be a first stage rotor within a high pressure turbine, and the vane stage may be a second turbine vane stage within the high pressure turbine.
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In any of the aspects or embodiments described above and herein, the BOAS support ring may have a plurality of first support hangers, and each BOAS segment may include second support hangers configured to engage with the first support hangers.
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In any of the aspects or embodiments described above and herein, each spring clip may include an SC central segment having a first axial side and a second axial side opposite the first axial side, and the forward segment may extend outwardly from the first axial side, and the aft segment may extend outwardly from the first axial side or the second axial side.
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In any of the aspects or embodiments described above and herein, at least a portion of the SC aft segments may extend in a first radial direction, and the SC engagement segments may extend in a second radial direction, and the second radial direction is opposite the first radial direction.
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According to a second aspect of the present invention, a blade outer air seal (BOAS) assembly for a gas turbine engine rotor (e.g., a rotor of a gas turbine engine according to the first aspect of the invention or any embodiments thereof described herein) is provided that includes a BOAS support ring (e.g., an annular BOAS support ring which may surround a central axis), a plurality of BOAS segments, and a plurality of spring clips. The annular BOAS support ring has an aft or downstream external surface (e.g., configured to be orientated in a downstream direction when in use). The BOAS segments are disposed radially inside of the annular BOAS support ring. The spring clips are engaged with the BOAS segments and the BOAS support ring. Each spring clip includes a forward segment, an aft segment, and an engagement segment. The BOAS assembly is disposable in an engaged configuration, and in the engaged configuration the forward segments of the spring clips are engaged with a surface of the BOAS support ring, the aft segments of the spring clips are engaged with the aft external surface of the BOAS support ring, and the engagement segments of the spring clips are engaged with the plurality of BOAS segments. In the engaged configuration, the spring clips are configured to bias the plurality of BOAS segments in an aft or downstream axial direction (e.g., relative to the central axis and/or an axis of an engine in which the BOAS assembly is configured to be used and/or a flow of gases through said engine).
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In any of the aspects or embodiments described above and herein, the forward segment of each spring clip may include a first lateral side member and a second lateral side member spaced apart from one another (e.g., circumferentially spaced apart).
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In any of the aspects or embodiments described above and herein, the forward segment of each spring clip may have a forward segment distal end and the first lateral side member and the second lateral side member may be connected to one another at the forward segment distal end.
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In any of the aspects or embodiments described above and herein, the aft segment (AS) of each spring clip may include a first AS lateral side member and a second AS lateral side member spaced apart from one another (e.g., circumferentially spaced apart), and the aft segment of each spring clip may have an aft segment distal end and the first and second AS lateral side members may be connected to one another at the aft segment distal end.
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In any of the aspects or embodiments described above and herein, the engagement segment of each spring clip may extend outwardly (axially and or radially outwardly) from the second axial side of the central segment.
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In any of the aspects or embodiments described above and herein, the forward segment may extend outwardly from the first axial side in a first axial direction, and the aft segment may curve away from the SC central segment and extend axially in a second axial direction opposite the first axial direction.
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In any of the aspects or embodiments described above and herein, the engagement segment may have an arcuately shaped configuration and the forward segment may extend out from a first side of the engagement segment, and the aft segment may extend out from a second side of the engagement segment.
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The foregoing features and elements may be combined in various combinations without exclusivity, unless expressly indicated otherwise. For example, aspects and/or embodiments of the present disclosure may include any one or more of the individual features or elements disclosed above and/or below alone or in any combination thereof. These features and elements as well as the operation thereof will become more apparent in light of the following description and the accompanying drawings. It should be understood, however, the following description and drawings are intended to be exemplary in nature and non-limiting.
BRIEF DESCRIPTION OF THE DRAWINGS
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- FIG. 1 is a diagrammatic sectional view of a gas turbine engine embodiment.
- FIG. 2 is a diagrammatic sectional view of a portion of a turbine section.
- FIG. 3 is a diagrammatic cross-sectional view of a blade outer air seal embodiment.
- FIG. 4 is a diagrammatic perspective view of a spring clip embodiment.
- FIG. 5 is a diagrammatic representation of a blade outer air seal assembly with the BOAS support ring and the BOAS segment not engaged.
- FIG. 5A is a diagrammatic representation of the blade outer air seal assembly shown in FIG. 5, with the BOAS support ring and the BOAS segment partially engaged.
- FIG. 5B is a diagrammatic representation of the blade outer air seal assembly shown in FIG. 5, with the BOAS support ring and the BOAS segment fully engaged.
- FIG. 6 is a diagrammatic representation of the blade outer air seal assembly fully engaged with the BOAS segment biased against a seal.
- FIGS. 7-7C diagrammatically illustrate present disclosure spring clip embodiments.
- FIG. 7D diagrammatically illustrates a generic version of the spring clip embodiments shown in FIGS. 7 and 7C, now engaged with a BOAS segment and a BOAS support ring.
- FIG. 8 is a diagrammatic perspective view of a spring clip embodiment.
- FIG. 8A diagrammatically illustrates the spring clip embodiment shown in FIG. 8 engaged with a BOAS segment and a BOAS support ring.
- FIG. 9 is a diagrammatic perspective view of a spring clip embodiment.
- FIG. 9A diagrammatically illustrates the spring clip embodiment shown in FIG. 9 engaged with a BOAS segment and a BOAS support ring.
DETAILED DESCRIPTION
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FIG. 1 diagrammatically illustrates a gas turbine engine 20. The gas turbine engine 20 is disclosed herein as a two-spool low-bypass turbofan that generally incorporates a fan section 22, a compressor section 24, a combustor section 26, a turbine section 28 (HPT 28A, LPT 28B), an exhaust duct section 32, and a nozzle 34 disposed along a longitudinal engine axis / centerline 36. The gas turbine engine 20 is disposed in a nacelle 38. Although the gas turbine engine 20 is shown as a low bypass turbofan in FIG. 1, it should be understood that the concepts described herein are not limited to use with a low bypass turbofan, and may be used with a variety of different gas turbine engine architectures, including geared architecture engines, direct drive turbofans, turbojet, turboshaft, multi-stream variable cycle adaptive engines and other engine architectures.
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The gas turbine engine 20 diagrammatically shown in FIG. 1 further includes an engine case 40 disposed radially outside of the compressor, combustor, and turbine sections 24, 26, 28 of the engine 20 and radially inside of (and spaced apart from) the nacelle 38. A generally annular secondary airflow path 42 is disposed between the engine case 40 and the nacelle 38. A gas path (referred to herein as the "core gas path 44") extends through the compressor, combustor, and turbine sections 24, 26, 28.
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A portion of the air that enters the engine 20 (i.e., the "inlet air"), passes through the fan section 22 and enters the secondary airflow path 42. This portion of the inlet air may be referred to as "bypass airflow". The remaining portion of the inlet air enters the core gas path 44. More specifically, this portion of the inlet air enters the compressor section 24 where it is worked to a higher pressure and temperature. The now "worked" air subsequently enters the combustor section 26 where fuel is added and the mixture is combusted. The gaseous combustion products and any non-combusted air passes to the turbine section 28. To facilitate the description herein, air passing through the compressor section 24 and into the combustor section 26, and the gaseous combustion byproducts passing through the turbine section 28 will all be referred to herein as "core gas flow", unless otherwise noted. The bypass air flow and the core gas flow are both directed through the nozzle 34 to produce useful thrust. In some applications, bypass airflow and/or core gas flow bled off of the compressor section 24 may be utilized for a variety of different purposes, including for cooling and/or for pressurization.
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The terms "forward", "leading", "aft, "trailing" are used herein to indicate the relative position of a component or surface. As air passes through the engine 20, a leading edge of a stator vane or rotor blade encounters the air before the trailing edge of the same. In a conventional axial engine such as that shown in FIG. 1, the fan section 22 is forward of the compressor section 24 and the turbine section 28 is aft of the compressor section 24. The terms "inner radial" and "outer radial" refer to relative radial positions from the engine centerline 36. An inner radial component or path is disposed radially closer to the engine centerline 36 than an outer radial component or path.
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The turbine section 28 includes a plurality of rotor stages and stator vane stages. Each rotor stage includes a rotor having a disk and a plurality rotor blades extending radially out from the disk. The outer radial end of each rotor blade terminates at a blade tip. As will be detailed herein, a seal structure is disposed radially outside of the rotor to form a seal between the rotor tips and the seal structure. The present disclosure is not limited to any particular rotor configuration. Each stator vane stage may be an annular structure that includes a plurality of vanes that extend between an inner radial platform and an outer radial platform.
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FIG. 2 diagrammatically illustrates a portion of a turbine section 28 to provide an example of a present disclosure implementation. The portion includes a turbine inlet guide vane stage 46, a turbine first rotor stage 48, and a turbine second stator vane stage 50. The turbine inlet guide vane stage 46 is immediately downstream of, and contiguous with, the combustor section 26; e.g., see FIG. 1. The turbine first rotor stage 48 and the turbine second stator vane stage 50 are disposed axially downstream of the turbine inlet guide vane stage 46. The turbine inlet guide vane stage 46 is an annular structure that includes a plurality of inlet guide vanes 46A, each extending between an inner radial platform 46B and an outer radial platform 46C. The outer radial platform 46C of the turbine inlet guide vane stage 46 includes, or is connected with, support structure for mounting the annular turbine inlet guide vane stage 46. The turbine first rotor stage 48 includes a rotor 52 having a disk 52A and a plurality rotor blades 52B extending radially out from the disk 52A. Each rotor blade 52B includes a platform 52C and an airfoil 52D. The airfoil 52D extends from the platform 52C to a blade tip 54. A blade outer air seal (BOAS) assembly 56 is disposed radially outside of the rotor blade 52B around the circumferential periphery of the rotor stage 48. The BOAS assembly 56 includes a support ring 58 and a plurality of BOAS segments 60. The BOAS segments 60 are disposed radially inside of the BOAS support ring 58. The turbine second stator vane stage 50 is an annular structure that includes a plurality of second stage vanes 62, each extending between an inner radial platform 62A and an outer radial platform 62B. The outer radial platform 62B of the turbine second stator vane stage 50 includes or is in connection with support structure 64 that mounts the annular turbine second stator vane stage 50. A seal (referred to hereinafter as an "inter-stage seal 66") may be disposed to seal the gap between the second stator vane stage 50 outer radial support structure 64 and the BOAS segment 60. The term "seal" is used herein to mean the structure functions to decrease or stop the flow of gas across the seal. The inter-stage seal 66 is not limited to any particular configuration. Non-limiting examples of types of an inter-stage seal 66 include a brush seal, a W-seal, or the like.
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As will be detailed herein, the present disclosure is configured to bias each BOAS segment 60 toward, and preferably into engagement with, the inter-stage seal 66. The term "bias" as used herein means that each BOAS segment 60 is loaded toward the inter-stage seal 66 (and in some instances, against the seal 66) by a spring force. Aspects of the present disclosure use spring clips 68 to bias the BOAS segments 60 in a direction toward the inter-stage seal 66.
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FIG. 3 diagrammatically illustrates an exemplary cross-section of a BOAS segment 60 that may be used with the present disclosure. The BOAS segment 60 has a forward end 70, an aft end 72, a tip seal surface 74, an outer radial surface 76, an aft surface 78, a spring pocket 80, and a plurality of hangers 82 (including forward hangers 82A and aft hangers 82B) extending radially out from the outer radial surface 76. The BOAS segment hangers 82 are configured to engage with BOAS support ring hangers 84; e.g., see FIGS. 5-5B. The present disclosure is not limited to any particular BOAS segment hanger 82 configuration. The present disclosure is not limited to any particular BOAS segment 60 structure other than as described herein relative to use with a present disclosure spring clip 68.
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FIG. 4 is diagrammatic perspective view of a present disclosure spring clip 68 embodiment. The spring clip 68 includes a forward segment 86, a central segment 88, an aft segment 90, and an engagement segment 92. The spring clip 68 extends along an axial centerline 94. The forward segment 86 extends generally axially outward from a first axial side of the central segment 88 to a forward segment distal end 86A. The forward segment 86 includes a first lateral side member 86B and a second lateral side member 86C that are spaced apart from one another by a void. The forward segment first and second lateral side members 86B, 86C are connected to one another at the forward segment distal end 86A. The aft segment 90 extends generally radially outward from a second axial side of the central segment 88 (opposite the first axial side) to an aft segment distal end 90A. The aft segment 90 includes a first lateral side member 90B and a second lateral side member 90C that are spaced apart from one another by a void. The aft segment first and second lateral side members 90B, 90C are connected to one another at the aft segment distal end 90A. The engagement segment 92 extends outwardly from the second axial side of the central segment 88 radially below the aft segment 90. The engagement segment 92 shown in FIG. 4 includes an arcuately shaped portion; e.g., semi-circularly shaped. The spring clip 68 example shown in FIG. 4 also includes a locating tang 96 extending out from the forward segment 86. The locating tang 96 is a cantilevered member aligned with the void disposed between the forward segment first and second lateral side members 86B, 86C. The locating tang 96 includes a distal tab 96A that extends in an upward radial direction.
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FIGS. 5-5B diagrammatically illustrate a BOAS segment 60 engaging with the BOAS support ring 58 in a step-wise fashion. In FIG. 5, the BOAS support ring 58 and the BOAS segment 60 are not engaged. The arrow shown to the left of the BOAS support ring 58 and the arrow shown to the right of the BOAS segment 60 illustrate the relative movement that will bring the elements together. The spring clip 68 is shown mounted on the BOAS segment 60. The forward segment distal end 86A of the spring clip 68 is disposed adjacent the forward end 70 of the BOAS segment 60 and the aft segment 90 extends radially above the hangers 82. The spring clip 68 engagement segment 92 is shown engaged within a pocket 80 formed on the outer radial surface 76 of the BOAS segment 60.
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In FIG. 5A, the BOAS support ring 58 and the BOAS segment 60 are partially engaged with one another, and the arrows illustrate the relative movement of the BOAS support ring 58 and the BOAS segment 60. In FIG. 5A, the hangers 82 of the BOAS segment 60 are not yet engaged with the hangers 84 of the BOAS support ring 58. However, the forward segment 86 of the spring clip 68 has engaged the BOAS support ring 58 and has elastically deflected as a result. The distal tab 96A of the locating tang 96 is engaged with a surface of the BOAS support ring 58, thereby causing (at least partially) the elastic deflection of the tang 96. The aft segment 90 of the spring clip 68 extends radially above the hangers 82 but is not engaged with the BOAS support ring 58. The spring clip engagement segment 92 is engaged within the pocket 80 formed on the outer radial surface 76 of the BOAS segment 60.
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In FIG. 5B, the BOAS support ring 58 and the BOAS segment 60 are fully engaged with one another, including the respective hangers 82, 84. This configuration of the BOAS assembly 56 may be referred to as the "engaged configuration". In this position, the distal tab 96A of the locating tang 96 has released from the surface of the BOAS support ring 58, the forward segment 86 is engaged with a surface of the BOAS support ring 58 (e.g., an inner radial surface), the aft segment 90 is engaged with (e.g., biased against) an aft surface 98 of the BOAS support ring 58, and the spring clip engagement segment 92 is engaged in the pocket 80 formed on the outer radial surface 76 of the BOAS segment 60. In this configuration, the spring clip 68 biases the BOAS segment 60 in the direction forward to aft as indicated by the arrow.
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FIG. 6 shows the fully engaged BOAS support ring 58 and the BOAS segment 60 as shown in FIG. 5B, and also diagrammatically illustrates an inter-stage seal 66 engaged with the BOAS segment 60. The arrow illustrates the direction of linear translation that the BOAS segment 60 may experience, with the spring clip 68 normally biasing the BOAS segment 60 toward (and preferably into engagement with) the inter-stage seal 66.
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As indicated above, the present disclosure is not limited to the spring clip 68 embodiment shown in FIG. 4. FIGS. 7-7C illustrate alternative present disclosure spring clip 68 embodiments. In the embodiments shown in FIGS. 7-7C, each of the spring clips 68 includes a forward segment 86, a central segment 88, an aft segment 90, a spring clip engagement segment 92, and each spring clip 68 extends along an axial centerline 94. In these embodiments, the forward segment 86 and the aft segment 90 may be described as extending out from the same axial side of the central segment 88. In each of these embodiments, the aft segment 90 curves away from the central segment 88 and extends axially away from the forward segment 86; e.g., extends in an aft direction. In each of these embodiments, the aft segment 90 includes a distal end portion that diverts at about a right angle in a direction away from the central segment 88. In the embodiments shown in FIGS. 7 and 7A, the forward segment 86 is a single member and the aft segment 90 includes an aft segment first lateral side member 90B and an aft segment second lateral side member 90C. In the embodiment shown in FIGS. 7B and 7C, the forward segment 86 includes a forward segment first lateral side member 86B and a forward segment second lateral side member 86C and the aft segment 90 is a single member. In the spring clip 68 embodiments shown in FIGS. 7-7C, the spring clip engagement segment 92 extends out from the central segment 88 on the axial side opposite the side from which the forward and aft segments 86, 90 extend.
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In addition to the differences identified above, the spring clip 68 embodiments shown in FIGS. 7-7B also have other configuration differences including different spring clip engagement segment 92 curvatures. The embodiments shown in FIGS. 7A and 7B have a planar central segment 88 and the embodiment shown in FIG. 7 has an arcuately shaped central segment 88. The spring clip 68 embodiment shown in FIG. 7C includes bumper features 100 that extend out from the same axial side of the central segment 88 as the forward and aft segments 86, 90. The bumper features may be configured to facilitate locating the spring clips 68 during installation and/or during operation.
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FIG. 7D generically illustrates all of the embodiments shown in FIGS. 7-7C engaged with the BOAS segment 60 and the BOAS support ring 58. For example, the forward segment 86 of the spring clip 68 is engaged with a surface of the BOAS support ring 58, the aft segment 90 of the spring clip 68 is engaged with (e.g., biased against) an aft surface 98 of the BOAS support ring 58, and the spring clip engagement segment 92 is engaged with a surface of the BOAS segment 60; e.g., a surface of a forward hanger 82. In all of these embodiments, the spring clip 68 biases the BOAS segment 60 in the direction forward to aft as indicated by the arrow.
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FIGS. 8 and 8A illustrate another present disclosure spring clip 68 embodiment. FIG. 8 is a diagrammatic perspective view of the spring clip 68. In this embodiment, the spring clip 68 includes a forward segment 86, an aft segment 90, and a spring clip engagement segment 92. The spring clip 68 extends along an axial centerline. In this embodiment, the spring clip engagement segment 92 has an arcuately shaped configuration. The forward segment 86 and the aft segment 90 may be described as extending out from opposite sides of the spring clip engagement segment 92; e.g., the forward segment 86 extends axially in a forward direction and radially upward from the spring clip engagement segment 92, and the aft segment 90 extends generally radially upward from the spring clip engagement segment 92. FIG. 8A diagrammatically illustrates the spring clip 68 engaged with a BOAS segment 60 and a BOAS support ring 58, wherein the forward segment 86 of the spring clip 68 is engaged with a BOAS support ring surface, the aft segment 90 of the spring clip 68 is engaged with (e.g., biased against) an aft surface 98 of the BOAS support ring 58, and the spring clip engagement segment 92 is engaged with a surface of the BOAS segment 60; e.g., a surface of an aft hanger. In all of these embodiments, the spring clip 68 biases the BOAS segment 60 in the direction forward to aft as indicated by the arrow.
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FIGS. 9 and 9A illustrate another present disclosure spring clip 68 embodiment, similar to that shown in FIGS. 8 and 8A. In this embodiment, the spring clip 68 includes a forward segment 86 and a spring clip engagement segment 92 like that shown in FIGS. 8 and 8A, and the forward segment 86 and the aft segment 90 extend out from opposite sides of the spring clip engagement segment 92. In this embodiment, the aft segment 90 has a U-shaped configuration. FIG. 9A diagrammatically illustrates the spring clip 68 engaged with a BOAS segment 60 and a BOAS support ring 58, wherein the forward segment 86 of the spring clip 68 is engaged with a BOAS support ring surface, one leg of the U-shaped aft segment 90 is engaged with (e.g., biased against) an aft surface 98 of the BOAS support ring 58, and the spring clip engagement segment 92 is engaged with a surface of the BOAS segment 60; e.g., a surface of an aft hanger. In all of these embodiments, the spring clip 68 biases the BOAS segment 60 in the direction forward to aft as indicated by the arrow.
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During operation of a gas turbine engine 20, core gas flow within the turbine portion of the core gas path is typically at a very high temperature and pressure. As indicated herein, seals (e.g., inter-stage seals 66) are used to mitigate the leakage of core gas flow from the core gas path into the regions radially outside of the core gas path. An example of a region radially outside of the core gas path include is the region that contains the BOAS support ring 58. Substantial leakage of core gas flow can significantly alter the temperature of the BOAS support ring 58 and negatively affect the ability of the support ring 58 to function. Hence, sealing the core gas path is important, particularly in the turbine section 28 wherein rotor blade tip clearance is key to engine 20 performance and efficiency.
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The present disclosure blade outer air sealing system is understood to provide a significant improvement in sealing. As described herein, the spring clips 68 are configured to bias the BOAS segments 60 in the direction toward an aft located inter-stage seal 66, which seal 66 is intended to seal the outer radial gap between the BOAS segments 60 and the turbine second stator vane stage 50. In some embodiments, the spring clips 68 may be configured to bias the BOAS segments 60 into engagement with the aft located inter-stage seal 66. During operational phases of the gas turbine engine 20, the thermal environment can change dramatically. As a result, seal gaps can change dramatically. At the same time, it is important for structures to be able to thermally grow or retract without detrimental interference. The present disclosure permits existing types of seals to be used at a BOAS gap in a manner that provides greater gap control and consequent sealing.
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While the principles of the disclosure have been described above in connection with specific apparatuses and methods, it is to be clearly understood that this description is made only by way of example and not as limitation on the scope of the disclosure. Specific details are given in the above description to provide a thorough understanding of the embodiments. However, it is understood that the embodiments may be practiced without these specific details.
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It is noted that the embodiments may be described as a process which is depicted as a flowchart, a flow diagram, a block diagram, etc. Although any one of these structures may describe the operations as a sequential process, many of the operations can be performed in parallel or concurrently. In addition, the order of the operations may be rearranged. A process may correspond to a method, a function, a procedure, a subroutine, a subprogram, etc.
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The singular forms "a," "an," and "the" refer to one or more than one, unless the context clearly dictates otherwise. For example, the term "comprising a specimen" includes single or plural specimens and is considered equivalent to the phrase "comprising at least one specimen." The term "or" refers to a single element of stated alternative elements or a combination of two or more elements unless the context clearly indicates otherwise. As used herein, "comprises" means "includes." Thus, "comprising A or B," means "including A or B, or A and B," without excluding additional elements.
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It is noted that various connections are set forth between elements in the present description and drawings (the contents of which are included in this disclosure by way of reference). It is noted that these connections are general and, unless specified otherwise, may be direct or indirect and that this specification is not intended to be limiting in this respect. Any reference to attached, fixed, connected or the like may include permanent, removable, temporary, partial, full and/or any other possible attachment option.
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No element, component, or method step in the present disclosure is intended to be dedicated to the public regardless of whether the element, component, or method step is explicitly recited in the claims. As used herein, the terms "comprise", "comprising", or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.
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While various inventive aspects, concepts and features of the disclosures may be described and illustrated herein as embodied in combination in the exemplary embodiments, these various aspects, concepts, and features may be used in many alternative embodiments, either individually or in various combinations and sub-combinations thereof. Unless expressly excluded herein all such combinations and sub-combinations are intended to be within the scope of the present application. Still further, while various alternative embodiments as to the various aspects, concepts, and features of the disclosures--such as alternative materials, structures, configurations, methods, devices, and components, and so on--may be described herein, such descriptions are not intended to be a complete or exhaustive list of available alternative embodiments, whether presently known or later developed. Those skilled in the art may readily adopt one or more of the inventive aspects, concepts, or features into additional embodiments and uses within the scope of the present application even if such embodiments are not expressly disclosed herein. For example, in the exemplary embodiments described above within the Detailed Description portion of the present specification, elements may be described as individual units and shown as independent of one another to facilitate the description. In alternative embodiments, such elements may be configured as combined elements. It is further noted that various method or process steps for embodiments of the present disclosure are described herein. The description may present method and/or process steps as a particular sequence. However, to the extent that the method or process does not rely on the particular order of steps set forth herein, the method or process should not be limited to the particular sequence of steps described. As one of ordinary skill in the art would appreciate, other sequences of steps may be possible.