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Title:
SEPARATOR PLATE WITH INLET CURVE
Document Type and Number:
WIPO Patent Application WO/2016/205651
Kind Code:
A1
Abstract:
A scroll compressor includes a housing comprising a cylindrical shell arranged about a vertically-extending axis, and scroll compressor bodies, including a fixed scroll compressor body and a movable scroll compressor body. The scroll compressor bodies are disposed in the housing and have respective bases and respective scroll ribs that project from the respective bases and which mutually engage for compressing fluid. An electrical motor has a stator and rotor. There is a drive shaft and rotor that acts upon the drive shaft that acts upon the scroll compressor bodies to facilitate relative movement between the scroll compressor bodies. A separator plate is disposed in the housing to separate a high-pressure region from a lower pressure region. The separator plate has a central opening. A perimeter of the central opening is defined by a curved inner wall. The curved inner wall is joined to an outer wall via an annular plate.

Inventors:
DUPPERT, Ronald J. (223 Palmer Drive, Fayetteville, New York, 13066, US)
Application Number:
US2016/038079
Publication Date:
December 22, 2016
Filing Date:
June 17, 2016
Export Citation:
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Assignee:
BITZER KÜHLMASCHINENBAU GMBH (Eschenbruennlestrasse 15, Sindelfingen, Sindelfingen, DE)
DUPPERT, Ronald J. (223 Palmer Drive, Fayetteville, New York, 13066, US)
International Classes:
F04C18/02; F04C19/00
Foreign References:
US20130251575A12013-09-26
CN101614205A2009-12-30
US20020114720A12002-08-22
US20060228243A12006-10-12
US6203298B12001-03-20
Attorney, Agent or Firm:
WRIGHT, Gordon M. (Reinhart Boerner Van Deuren, 2215 Perrygreen WayRockford, Illinois, 61107, US)
Download PDF:
Claims:
WHAT IS CLAIMED IS:

1. A scroll compressor comprising:

a housing comprising a cylindrical shell section arranged about an axis that is vertically extending;

scroll compressor bodies, including a fixed scroll compressor body and a movable scroll compressor body, the scroll compressor bodies being disposed in the housing and having respective bases and respective scroll ribs that project from the respective bases and which mutually engage for compressing fluid;

a drive unit having a rotor and a stator;

a drive shaft for rotation, the rotor acting upon the drive shaft, which, in turn, acts upon the scroll compressor bodies to facilitate relative orbiting movement between the scroll compressor bodies; and

a separator plate disposed in the housing and arranged to separate a high-pressure region from a relatively lower pressure region, the separator plate having a central opening, a perimeter of the central opening defined by a curved inner wall, the curved inner wall joined to an outer wall via an annular plate.

2. The scroll compressor of claim 1, wherein the curved inner wall is configured to receive a central hub of the fixed scroll compressor body.

3. The scroll compressor of claim 1, wherein the curved inner wall curves toward the outer wall at an entrance point where the fixed scroll compressor body enters the separator plate central opening.

4. The scroll compressor of claim 1, wherein the outer wall abuts an inner surface of the housing.

5. The scroll compressor of claim 1, wherein the annular plate is frusto-conical.

6. A method of manufacturing a scroll compressor comprising the steps of:

attaching a separator plate into an interior portion of a housing for the scroll

compressor; and

inserting a fixed scroll compressor body into a central opening of the separator plate, a perimeter of the central opening defined by a curved inner wall, the curved inner wall joined to an outer wall via an annular plate.

7. The method of claim 6, wherein attaching a separator plate into an interior portion of a housing for the scroll compressor comprises attaching the outer wall of the separator plate to an interior wall of the housing.

8. The method of claim 6, wherein inserting a fixed scroll compressor body into a central opening of the separator plate comprises inserting a central hub of the fixed scroll compressor body into the central opening.

9. The method of claim 8, further comprising assembling an O-ring onto the central hub to create a seal between the fixed scroll compressor and the separator plate.

10. The method of claim 6, wherein the curved inner wall curves toward the outer wall at an entrance point where the fixed scroll compressor body enters the separator plate central opening.

Description:
SEPARATOR PLATE WITH INLET CURVE

FIELD OF THE INVENTION

[0001] This invention generally relates to compressors, and more particularly to scroll compressors having a separator plate with an inlet curve or curved inner wall.

BACKGROUND OF THE INVENTION

[0002] A scroll compressor is a certain type of compressor that is used to compress refrigerant for such applications as refrigeration, air conditioning, industrial cooling and freezer applications, and/or other applications where compressed fluid may be used. Such prior scroll compressors are known, for example, as exemplified in U.S. Pat. No. 6,398,530 to Hasemann; U.S. Pate. No. 6,814,551, to Kammhoff et al.; U.S. Pat. No. 6,960,070 to Kammhoff et al.; U.S. Pat. No. 7,112,046 to Kammhoff et al.; and U.S. Pat. No. 7,997,877, to Beagle et al., all of which are assigned to a Bitzer entity closely related to the present assignee. As the present disclosure pertains to improvements that can be implemented in these or other scroll compressor designs, the disclosures of U.S. Pat. Nos. 6,398,530, 7,112,046, 6,814,551, and 6,960,070 are hereby incorporated by reference in their entireties.

[0003] Additionally, particular embodiments of scroll compressors are disclosed in U.S. Pat. No. 6,582,211 to Wallis et al., U.S. Pat. No. 6,428,292 to Wallis et al., and U.S. Pat. No. 6, 171,084 to Wallis et al., the teachings and disclosures of which are hereby incorporated by reference in their entireties.

[0004] As is exemplified by these patents, scroll compressors conventionally include an outer housing having a scroll compressor contained therein. A scroll compressor includes first and second scroll compressor members. A first compressor member is typically arranged stationary and fixed in the outer housing. A second scroll compressor member is moveable relative to the first scroll compressor member in order to compress refrigerant between respective scroll ribs which rise above the respective bases and engage in one another.

Conventionally the moveable scroll compressor member is driven about an orbital path about a central axis for the purpose of compressing refrigerant. An appropriate drive unit, typically an electric motor, is usually provided within the same housing to drive the movable scroll member.

[0005] In conventional compressors, for example scroll compressors, a separator plate may be used to separate high-pressure regions from low-pressure regions. Typically, these separator plates include a central bore which is machined after the separator plate is stamped. This machining allows for looser position tolerances during final assembly. However, this machining adds cost, additional complexity, and additional time to the manufacturing process.

[0006] Embodiments of the invention address certain of the aforementioned problems encountered during the manufacture of compressors, particularly, scroll compressors. These and other advantages of the invention, as well as additional inventive features, will be apparent from the description of the invention provided herein.

BRIEF SUMMARY OF THE INVENTION

[0007] In one aspect, embodiments of the invention provide a scroll compressor with a housing comprising a cylindrical shell arranged about a vertically-extending axis, and scroll compressor bodies, including a fixed scroll compressor body and a movable scroll compressor body. The scroll compressor bodies are disposed in the housing and have respective bases and respective scroll ribs that project from the respective bases and which mutually engage for compressing fluid. An electrical motor has a stator and rotor. There is a drive shaft and rotor that acts upon the drive shaft that acts upon the scroll compressor bodies to facilitate relative orbital movement between the scroll compressor bodies. A separator plate is disposed in the housing to separate a high-pressure region from a relatively lower pressure region. The separator plate has a central opening. A perimeter of the central opening is defined by a curved inner wall. The curved inner wall is joined to an outer wall via an annular plate.

[0008] In a particular embodiment, the curved inner wall is configured to receive a central hub of the fixed scroll compressor body. The curved inner wall may curve towards the outer wall at an entrance point where the fixed scroll compressor body enters the separator plate central opening. In certain embodiments, the outer wall abuts an inner surface of the housing. Further, the aforementioned annular plate may be frusto-conical.

[0009] In another aspect, embodiments of the invention provide a method of manufacturing a scroll compressor. The method may include attaching a separator plate into an interior portion of a housing for the scroll compressor, and inserting a fixed scroll compressor body into a central opening of the separator plate. A perimeter of the central opening is defined by a curved inner wall. The curved inner wall is joined to an outer wall via an annular plate.

[0010] Attaching a separator plate into an interior portion of a housing for the scroll compressor may include attaching the outer wall of the separator plate to an interior wall of the housing. In a further embodiment, inserting a fixed scroll compressor body into a central opening of the separator plate may include inserting a central hub of the fixed scroll compressor body into the central opening.

[0011] The method may further include assembling an O-ring, lip seal, or spring-energized seal onto the central hub to create a seal between the fixed scroll compressor and the separator plate. In some embodiments, the curved inner wall curves toward the outer wall at an entrance point where the fixed scroll compressor body enters the separator plate central opening.

[0012] Other aspects, objectives and advantages of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The accompanying drawings incorporated in and forming a part of the specification illustrate several aspects of the present invention and, together with the description, serve to explain the principles of the invention. In the drawings:

[0014] FIG. 1 is a cross-sectional isometric view of a scroll compressor assembly, according to an embodiment of the invention; [0015] FIG. 2 is a cross-sectional isometric view of an upper portion of the scroll compressor assembly of FIG. 1;

[0016] FIG. 3 is a cross-sectional isometric view of a top portion of the scroll compressor assembly of FIG. 1;

[0017] FIG. 4 is a cross-sectional isometric view of a lower portion of the scroll compressor assembly of FIG. 1

[0018] FIG. 5 is a cross-sectional view of the upper portion of a compressor with a separator plate, according to an embodiment of the invention; and

[0019] FIG. 6 is a cross-sectional view of the upper portion of a scroll compressor with a separator plate and scroll compressor bodies, according to an embodiment of the invention.

[0020] While the invention will be described in connection with certain preferred embodiments, there is no intent to limit it to those embodiments. On the contrary, the intent is to cover all alternatives, modifications and equivalents as included within the spirit and scope of the invention as defined by the appended claims.

DETAILED DESCRIPTION OF THE INVENTION

[0021] An embodiment of the present invention is illustrated in FIGS. 1-4 as a scroll compressor assembly 10 generally including an outer housing 12 in which a scroll compressor 14 can be driven by a drive unit 16. The scroll compressor assembly 10 may be arranged in a refrigerant circuit for refrigeration, industrial cooling, freezing, air conditioning or other appropriate applications where compressed fluid is desired. Appropriate connection ports provide for connection to a refrigeration circuit and include a refrigerant inlet port 18 and a refrigerant outlet port 20 extending through the outer housing 12. The scroll compressor assembly 10 is operable through operation of the drive unit 16 to operate the scroll compressor 14 and thereby compress an appropriate refrigerant or other fluid that enters the refrigerant inlet port 18 and exits the refrigerant outlet port 20 in a compressed high-pressure state. [0022] The outer housing 12 for the scroll compressor assembly 10 may take many forms. In particular embodiments of the invention, the outer housing 12 includes multiple shell sections. In the embodiment of FIG. 1, the outer housing 12 includes a central cylindrical housing section 24, and a top end housing section 26, and a bottom end housing section 28. In certain embodiments, the housing sections 24, 26, 28 are formed of appropriate sheet steel and welded together to make a permanent outer housing 12 enclosure. However, if disassembly of the housing is desired, other housing assembly provisions can be made that can include metal castings or machined components, wherein the housing sections 24, 26, 28 are attached using fasteners.

[0023] As can be seen in the embodiment of FIG. 1, the central housing section 24 is cylindrical, joined with the top end housing section 26. In this embodiment, a separator in the form of separator plate 30 is disposed in the top end housing section 26. Each of the top and bottom end housing sections 26, 28 are generally dome shaped and include respective cylindrical side wall regions 32, 34 that assemble to the center section 24 and provide for closing off the top and bottom ends of the outer housing 12. As can be seen in FIG. 1, the top side wall region 32 telescopically overlaps the central housing section 24 and is exteriorly welded along a circular welded region to the top end of the central housing section 24.

Similarly, a bottom portion of the central cylindrical housing section 24 overlaps the side wall region 34.

[0024] During assembly, these components may be assembled such that a single circumferential weld around the inner surface of the outer housing 12 joins the top end housing section 26 and the separator plate 30. A second circumferential weld may externally join the top end housing section 26 and central cylindrical housing section 24. In particular embodiments, the central cylindrical housing section 24 is welded to the bottom shell 28, though, as stated above, alternate embodiments would include other methods of joining (e.g., fasteners) these sections of the outer housing 12.

[0025] While the separator plate 30 could be a stamped steel component, it could also be constructed as a cast and/or machined member (and may be made from steel or aluminum) to provide the ability and structural features necessary to operate in proximity to the high-pressure refrigerant gases output by the scroll compressor 14. By casting or machining the separator plate 30 in this manner, heavy stamping of such components can be avoided.

[0026] Assembly of the outer housing 12 results in the formation of an enclosed chamber 31 that surrounds the drive unit 16, and partially surrounds the scroll compressor 14. In particular embodiments, the top end housing section 26 is generally dome-shaped and includes a respective cylindrical side wall region 32 that fits telescopically with the top of the central cylindrical housing section 24, and provides for closing off the top end of the outer housing 12.

[0027] In a particular embodiment, the drive unit 16 in is the form of an electrical motor assembly 40. The electrical motor assembly 40 operably rotates and drives a shaft 46. Further, the electrical motor assembly 40 generally includes an outer annular motor housing 48, a stator 50 comprising electrical coils and a rotor 52 that is coupled to the drive shaft 46 for rotation together. In a particular embodiment, the rotor 52 is mounted on the drive shaft 46, which is supported by upper and lower bearing members 42, 44. Energizing the stator 50 is operative to rotatably drive the rotor 52 and thereby rotate the drive shaft 46 about a central axis 54.

[0028] Applicant notes that when the terms "axial" and "radial" are used herein to describe features of components or assemblies, they are defined with respect to the central axis 54. Specifically, the term "axial" or "axially-extending" refers to a feature that projects or extends in a direction generally parallel to the central axis 54, while the terms "radial' or "radially- extending" indicates a feature that projects or extends in a direction generally perpendicular to the central axis 54. Some minor variation from parallel and perpendicular is permissible.

[0029] With reference to FIGS. 1 and 4, the lower bearing member 44 includes a central generally cylindrical hub 58 that includes a central bushing and opening to provide a cylindrical bearing 60 to which the drive shaft 46 is journaled for rotational support. A plurality of arms 62 and typically at least three arms project radially outward from the bearing central hub 58 preferably at equally spaced angular intervals. These support arms 62 engage and are seated on a circular seating surface 64 provided by the terminating circular edge of the bottom side wall region 34 of the bottom outer housing section 28. As such, the bottom housing section 28 can serve to locate, support and seat the lower bearing member 44 and thereby serves as a base upon which the internal components of the scroll compressor assembly can be supported.

[0030] Referring to FIG. 4, the lower bearing member 44 in turn supports the cylindrical motor housing 48 by virtue of a circular seat 66 formed on a plate-like ledge region 68 of the lower bearing member 44 that projects outward from the central hub 58. The support arms 62 also preferably are closely toleranced relative to the inner diameter of the central housing section 24. The arms 62 may engage with the inner diameter surface of the central housing section 24 to centrally locate the lower bearing member 44 and thereby maintain position of the central axis 54. This can be by way of an interference and press-fit support arrangement between the lower bearing member 44 and the outer housing 12. Alternatively, according to a more preferred configuration shown in FIG. 1, the lower bearing member 44 engages with the lower housing section 28 which is in turn attached to center section 24. Likewise, the outer motor housing 48 may be supported with an interference and press-fit along the stepped seat 66 of the lower bearing member 44. In some embodiments, screws may be used to securely fasten the motor housing 48 to the lower bearing member 44.

[0031] The drive shaft 46 further includes an offset eccentric drive section 74 that has a cylindrical drive surface 75 about an offset axis that is offset relative to the central axis 54. This offset drive section 74 is journaled within a cavity of the movable scroll member 112 of the scroll compressor 14 to drive the movable scroll member 112 of the scroll compressor 14 about an orbital path when the drive shaft 46 is rotated about the central axis 54. To provide for lubrication of all of these bearing surfaces, the outer housing 12 provides an oil lubricant sump 76 at the bottom end in which suitable oil lubricant is provided. The drive shaft 46 has an impeller tube 47 that acts as an oil pump when the drive shaft 46 is spun and thereby pumps oil out of the lubricant sump 76 into an internal lubricant passageway 80 within the drive shaft 46. During rotation of the drive shaft 46, centrifugal force acts to drive lubricant oil up through the lubricant passageway 80 against the action of gravity. In a particular embodiment, the lubricant passageway 80 includes various radial passages to feed oil through centrifugal force to appropriate bearing surfaces and thereby lubricate sliding surfaces as may be desired. [0032] The upper bearing member, or crankcase, 42 includes a central bearing hub 87 into which the drive shaft 46 is journaled for rotation. Extending outward from the central bearing hub 87 is a disk-like portion 86 that terminates in an intermittent perimeter support surface 88. In the embodiments of FIGS. 2 and 3, the central bearing hub 87 extends below the disk-like portion 86, while a thrust bearing 84 is assembled above the disk-like portion 86 and contains a thrust surface 96, which provides axial support for the moveable scroll compressor body 112. In certain embodiments, the intermittent perimeter support surface 88 is adapted to have an interference and press-fit with the outer housing 12. It is understood that alternate

embodiments of the invention may include crankcase posts with threaded holes to receive fasteners for assembly. Alternate embodiments of the invention also include those in which the posts are integral with a pilot ring instead of the crankcase.

[0033] Turning in greater detail to the scroll compressor 14, the scroll compressor body is provided by first and second scroll compressor bodies which preferably include a relatively stationary fixed scroll compressor member 110 and a second scroll compressor member 112 movable relative to the fixed scroll compressor member 110. The second scroll compressor member 112 is arranged for orbital movement relative to the fixed scroll compressor member 110 for the purpose of compressing refrigerant. The fixed scroll compressor member 110 includes a first rib 114 projecting axially from a plate-like base 116 and is designed in the form of a spiral. Similarly, the second movable scroll compressor body 112 includes a second scroll rib 118 projecting axially from a plate-like base 120 and is in the design form of a similar spiral.

[0034] The scroll ribs 114, 118 engage in one another and abut sealingly on the respective base surfaces 120, 116 of the respectively other compressor body 112, 110. As a result, multiple compression chambers 122 are formed between the scroll ribs 114, 118 and the bases 120, 116 of the respective compressor bodies 112, 1 10. Within the chambers 122, progressive compression of refrigerant takes place. Refrigerant flows with an initial low pressure via an intake area 124 surrounding the scroll ribs 114, 118 in the outer radial region. Following the progressive compression in the chambers 122 (as the chambers progressively are defined radially inward), the refrigerant exits via a discharge port 126 which is defined centrally within the base 116 of the fixed scroll compressor member 110. Refrigerant that has been compressed to a high pressure can exit the chambers 122 via the discharge port 126 during operation of the scroll compressor.

[0035] The movable scroll compressor body 112 engages the eccentric offset drive section 74 of the drive shaft 46. More specifically, the receiving portion of the movable scroll compressor body 112 includes a cylindrical bushing drive hub 128 which slideably receives the offset eccentric drive section 74 with a slideable bearing surface provided therein. In detail, the offset eccentric drive section 74 engages the cylindrical drive hub 128 in order to move the second scroll compressor member 112 about an orbital path about the central axis 54 during rotation of the drive shaft 46 about the central axis 54. Considering that this offset relationship causes a weight imbalance relative to the central axis 54, the assembly preferably includes a counter weight 130 that is mounted at a fixed angular orientation to the drive shaft 46.

[0036] The counter weight 130 acts to offset the weight imbalance caused by the eccentric offset drive section 74 and the movable scroll compressor body 112 that is driven about an orbital path (e.g. among other things, the scroll rib is not equally balanced). The counter weight 130 includes an attachment collar 132 and an offset weight region 134 that provides for the counter weight effect and thereby balancing of the forces of the rotating components about the central axis 54. This provides for reduced vibration and noise of the overall assembly by internally balancing or canceling out inertial forces.

[0037] Referring in greater detail to the fixed scroll compressor member 110, this body 110 is fixed to the upper bearing member 42, capturing the second scroll compressor member 112 between the fixed scroll member 110 and the upper bearing member 42. In a particular embodiment, the fixed scroll compressor body 110, together with the separator plate 30, separates a high pressure chamber 180 from the relatively lower pressure region of the compressor 14 contained within the outer housing 12. The central hub 178 of the fixed scroll compressor 110 body includes a circumferential O-ring groove 177, and when assembled with an O-ring 179, seals against the central cylindrical bore of the separator plate 30, preventing the return of high pressure compressed refrigerant to the relatively lower pressure region of the compressor assembly 14. At the interface between the separator plate 30 and the top end housing section 26, a fillet weld joins the end face of the outer cylindrical wall section of the separator plate 30 with the inside surface of the top end housing section 26, thus preventing the return of high pressure compressed refrigerant to the relatively lower pressure region of the compressor assembly 14.

[0038] The fillet weld allows for the separator plate 30 to be assembled to the top end housing section 26 prior to final assembly and weld of the compressor housing 12. This allows for inspection and confirmation of positional alignment between the central axis 54 of the top end housing section 26 and the central cylindrical bore of the separator plate 30.

[0039] FIG. 5 is a cross-sectional view of the upper portion of a compressor 10 with a separator plate 30, while FIG. 6 is a cross-sectional view of the upper portion of a scroll compressor 10 with a separator plate and scroll compressor bodies 110, 112, in accordance with an embodiment of the invention. The separator plate 30 is disposed in the housing 12 to separate a high-pressure region 200 from a relatively lower pressure region 202. The separator plate 30 has a central opening 204. A perimeter of the central opening 204 is defined by a curved inner wall 206. The curved inner wall 206 is joined to an outer wall 208 via an annular plate 212. In the embodiments of FIGS. 5 and 6, the annular plate 212 is frusto-conical, however other suitable configurations (both curved and flat, for example) for the annular plate 212 are envisioned.

[0040] In a particular embodiment such as shown in FIG. 6, the curved inner wall 206 is configured to receive a central hub 205 of the fixed scroll compressor body 110. The curved inner wall 206 may curve towards the outer wall 208 at an entrance point 209 where the fixed scroll compressor body 1 10 enters the separator plate central opening 204. In certain embodiments, the outer wall 208 abuts an inner surface 211 of the housing 12.

[0041] With respect to the assembly of the scroll compressor assembly 10, in certain embodiments, the separator plate 30 is attached by any suitable means (e.g., welding, mechanical fastener, interference fit, adhesives, etc.) to the inner surface 21 1 of the housing 12. The fixed scroll compressor body 110 is inserted into the central opening 204 of the separator plate 30.

[0042] In certain embodiments, an O-ring 213 is assembled to the central hub 205 of the fixed scroll compressor body 110 before insertion into the central opening 204 of the separator plate 30. The O-ring 213 creates a seal between the fixed scroll compressor body 110 and the curved inner wall 206 of the separator plate 30.

[0043] The design of the curved inner wall 206 eases the insertion of the fixed scroll compressor body 110 and its O-ring 213 into the central opening 204, without any machining the separator plate 30 after stamping. In many cases, these components are assembled by hand in such a manner that they may be misaligned as the central hub 205 of the fixed scroll compressor body 110 is introduced into the separator plate central opening 204. The shape of the curved inner wall 206 allows for this misalignment without damaging either the fixed scroll compressor body 110, the separator plate 30, or the O-ring 213.

[0044] In an exemplary manufacturing process, the separator plate 30 is manufactured using a stamping, or drawing process. During the manufacture, a die is inserted from the bottom of the central opening 204, generating this curve at entrance point 209. This curvature allows for relatively severe positional misalignment of the separator plate 30, relative to the fixed scroll compressor body 110 during manufacture, such as might occur during manual assembly. As the central hub 205 and separator plate 30 are assembled, the central hub 205 of the fixed scroll compressor body 110 progresses from the widest portion of the curved inner wall 206 to a relatively narrower cylindrical portion 215. Consequently, the geometry of the curved inner wall 206 centers the fixed scroll compressor body 110 relative to the separator plate 30.

[0045] All references, including publications, patent applications, and patents cited herein are hereby incorporated by reference to the same extent as if each reference were individually and specifically indicated to be incorporated by reference and were set forth in its entirety herein. [0046] The use of the terms "a" and "an" and "the" and similar referents in the context of describing the invention (especially in the context of the following claims) is to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The terms "comprising," "having," "including," and "containing" are to be construed as open-ended terms (i.e., meaning "including, but not limited to,") unless otherwise noted. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., "such as") provided herein, is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention.

[0047] Preferred embodiments of this invention are described herein, including the best mode known to the inventors for carrying out the invention. Variations of those preferred embodiments may become apparent to those of ordinary skill in the art upon reading the foregoing description. The inventors expect skilled artisans to employ such variations as appropriate, and the inventors intend for the invention to be practiced otherwise than as specifically described herein. Accordingly, this invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the invention unless otherwise indicated herein or otherwise clearly contradicted by context.