Fixed angle centrifuge rotor with tubular cavities and related methods

Abstract

To provide a fixed angle centrifuge rotor with tubular cavities.SOLUTION: A fixed angle centrifuge rotor (10) includes a rotor body (12) having an upper surface (34) and a plurality of tubular cavities (60) extending from the upper surface (34) to respective bottom walls (50). A pressure plate (14) is operatively coupled to the bottom walls (50) of the tubular cavities (60) and is configured to transfer torque to the bottom walls (50). The pressure plate (14) is configured to be directly coupled to a rotor hub (16) and to receive torque directly from the rotor hub (16).SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of U.S. Provisional Application No. 62 / 826,104, filed March 29, 2019, the disclosure of which is incorporated herein by reference in its entirety.

[0002] The present invention relates generally to centrifuge rotors, and more specifically to fixed angle rotors for use with centrifuges. [Background technology]

[0003] Centrifuge rotors are typically used in laboratory centrifuges to hold samples during centrifugation. Although centrifuge rotors can vary widely in construction and size, one common rotor design is a fixed-angle rotor with a solid rotor body with multiple cell hole cavities radially distributed within the rotor body and arranged symmetrically about the axis of rotation. Samples are positioned within the cavities, allowing multiple samples to be centrifuged.

[0004] Conventional fixed-angle centrifuge rotors can be fabricated from metal or a variety of other materials. However, a known improvement is to construct the centrifuge rotor by a compression molding and filament winding process in which the rotor is manufactured from a suitable material, such as composite carbon fiber. For example, a fixed-angle centrifuge rotor can be compression molded from layers of carbon fiber laminate material coated with resin. An example of a composite centrifuge rotor is described in U.S. Pat. No. 8,323,169, the disclosure of which is expressly incorporated herein by reference in its entirety.

[0005] Because centrifuge rotors are commonly used in high rotation applications where centrifuge speeds can exceed hundreds or thousands of revolutions per minute, centrifuge rotors must be able to withstand the stresses and strains that occur during the high speed rotation of the rotor under load. During centrifugation, a rotor with a sample loaded into its cavity experiences large forces along a radially outward direction from the cavity and along the longitudinal axis of the cavity, consistent with the centrifugal forces exerted on the sample container. These forces induce large stresses and strains in the rotor body.

[0006] Centrifuge rotors must be able to withstand the forces associated with rapid centrifugation over the life of the rotor. Manufacturers are continually working to develop centrifuge rotors that improve performance by accounting for the dynamic loads experienced during centrifugation, and address these and other issues associated with conventional rotors. Summary of the Invention

[0007] The present invention overcomes the above-mentioned and other deficiencies and drawbacks of previously known fixed-angle centrifuge rotors. While the present invention has been described in connection with specific embodiments, it is to be understood that the invention is not limited to these embodiments. On the contrary, the present invention includes all alternatives, modifications, and equivalents as may be included within the spirit and scope of the invention.

[0008] According to one embodiment, a fixed-angle centrifuge rotor is provided that includes a rotor body having a top surface and a plurality of tubular cavities extending from the top surface to a respective bottom wall, each cavity configured to receive a sample vessel therein.

[0009] The exemplary fixed angle centrifuge rotor also includes a pressure plate operatively coupled to the bottom walls of the plurality of tubular cavities configured to transmit torque to the bottom walls. According to one embodiment, the pressure plate is directly coupled to the rotor hub and configured to receive torque directly from the rotor hub.

[0010] In an exemplary embodiment, the pressure plate includes an upper surface and a plurality of spaced apart recesses on the upper surface, each recess including a bottom surface, the bottom surfaces of the plurality of recesses being capable of completely enveloping and engaging the bottom walls of the respective tubular cavities.

[0011] The pressure plate may include a lower surface and a plurality of spaced apart bores in the lower surface, each configured to receive a respective pin for directly coupling the pressure plate to the rotor hub.

[0012] The pressure plate may include a central bore configured to receive a shaft portion of the rotor hub. In one embodiment, the central bore is tapered. The pressure plate may include an outer side surface, which is also tapered.

[0013] In an exemplary embodiment, a fixed-angle centrifuge rotor includes a first elongated stiffener extending around at least one outer surface of the rotor body and at least one outer surface of the pressure plate along a first path, and a second elongated stiffener extending around the outer surface of the first elongated stiffener along a second path. In one embodiment, the first path may be circular and the second path may be helical.

[0014] An exemplary embodiment fixed angle centrifuge rotor may include a lid having a planar lower surface. The rotor body may include a planar upper surface that engages the planar lower surface of the lid. At least one of the planar lower surface of the lid or the planar upper surface of the rotor body may include a pair of annular grooves configured to receive a pair of O-rings.

[0015] According to one embodiment, the fixed angle centrifuge rotor may include a pressure ring extending around an outer surface of the rotor body and press-fitted into the rotor body. A first elongated stiffener may extend around at least one outer surface of the rotor body and at least one outer surface of the pressure ring along a first path. A second elongated stiffener may extend around the outer surface of the first elongated stiffener along a second path. In one embodiment, the first path may be circular and the second path may be helical.

[0016] A method of manufacturing a fixed angle centrifuge rotor according to one embodiment includes providing a rotor body including a plurality of tubular cavities, each cavity configured to receive a sample vessel therein. The exemplary method further includes disposing a plurality of cell cups within the plurality of cavities, each cell cup being received in a respective one of the cavities.

[0017] An exemplary method further includes providing a pressure plate, disposing a rotor body on the pressure plate, disposing a pressure ring on the rotor body, applying a first stiffener to at least the rotor body and the pressure plate, and applying a second stiffener to at least the pressure plate and the first stiffener.

[0018] Various additional features and advantages of the present invention will become more apparent to those skilled in the art upon review of the following detailed description of the illustrative embodiments in conjunction with the accompanying drawings. [Brief description of the drawings]

[0019] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the general description given above and the detailed description given below, serve to explain the invention.

[0020] [Figure 1] FIG. 1 is a perspective view of a centrifuge rotor according to one embodiment of the present invention.

[0021] [Diagram 2] FIG. 2 is an exploded perspective view of the centrifuge rotor of FIG. 1.

[0022] [Diagram 3] FIG. 2 is a partially exploded perspective view of the rotor body and pressure plate of the centrifuge rotor of FIG. 1.

[0023] [Figure 4] FIG. 2 is a cross-sectional view of the centrifuge rotor of FIG.

[0024] [Diagram 5] FIG. 5 is an enlarged cross-sectional view similar to FIG.

[0025] [Figure 6] FIG. 2 is a cross-sectional view of an alternative centrifuge rotor according to another embodiment of the present invention.

[0026] [Figure 7] FIG. 13 is a cross-sectional view of an alternative centrifuge rotor according to yet another embodiment of the present invention.

[0027] [Figure 8] 4 is a flow chart illustrating an exemplary method of manufacturing a centrifuge rotor in accordance with the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0028] 1 and 2, an exemplary centrifuge rotor 10 according to one embodiment of the present invention is shown. The rotor 10 includes a rotor body 12 and a pressure plate 14 that are fixedly coupled to one another and symmetrical about an axis of rotation R defined by a rotor hub 16, about which samples contained in sample containers 18 disposed in the rotor body 12 may be centrifugally spun. The rotor 10 also includes a lid 20 that is removably coupled to the rotor hub 16 on the rotor body 12 using lid screws 22, for example, to help retain the sample containers 18 within the rotor body 12 during rotation. As described in more detail below, first and second elongated stiffeners 24, 26 extend continuously around at least a portion of the rotor body 12 and the pressure plate 14, respectively.

[0029] 3-5 with continuing reference to FIGS. 1 and 2, the illustrated rotor body 12 includes a generally disk-shaped top plate 30 and a generally frustoconical bottom sidewall 32 extending downwardly and outwardly from the top plate 30. The top plate 30 includes an upper surface 34, a lower surface 36 (FIG. 3), and a first side 38, and the bottom sidewall 32 includes a second side 40. A circular bore 42 extends through the top plate 30 from the upper surface 34 to the lower surface 36 for receiving at least a shaft portion of the hub 16, and is configured to be coaxial with the hub 16 such that the bore 42 may also define an axis of rotation R. In one embodiment, the upper surface 34 of the top plate 30 is generally flat. The lower surface 36 of the top plate 30 and the inner surface of the bottom sidewall 32 together at least partially define an interior space 44 of the rotor body 12. In the embodiment shown, the first side 38 tapers radially inwardly slightly from the top surface 34 toward the second side 40. For example, the first side 38 may taper radially inwardly at an angle between about 3 degrees and about 10 degrees relative to a plane parallel to the axis of rotation R. In the embodiment shown, the first and second side 38, 40 are generally smooth. Here, "generally smooth" as used herein to describe the side 38, 40 is intended to describe a surface that does not have a stepped configuration and is generally free of corners or sharp edges. In this regard, the above defined terms are not intended to define the surface roughness of the surfaces 38, 40. Additionally, the rotor body 12 may be formed such that the generally smooth side 38, 40 does not require additional machining or finishing prior to application of the reinforcements 24, 26.

[0030] A plurality of tubular cell cup holders 46 extend from the underside 36 of the top plate 30 along the bottom sidewall 32 into the interior space 44 of the rotor body 12. In the embodiment shown, each tubular cell cup holder 46 is at least partially defined by the bottom sidewall 32 of the rotor body 12, a curved cup holder sidewall 48, and a contoured cup holder bottom wall 50 such that each tubular cell cup holder 46 has a generally elongated U-shaped cross-section (FIG. 4). As shown, each cell cup holder 46 has a respective longitudinal axis angled radially outwardly relative to the axis of rotation R. In this regard, the bottom sidewall 32 and cup holder sidewall 48 of the rotor body 12 are each angled radially outwardly relative to the axis of rotation R. For example, the bottom sidewall 32 and the holder sidewall 48 of the rotor body 12 may each be angled radially outwardly between about 20 degrees and about 25 degrees relative to the axis of rotation R, such that each cup holder 46 is angled radially outwardly between about 20 degrees and about 25 degrees relative to the axis of rotation R. In the embodiment shown, a first step 52 is provided between the bottom wall 50 and the cup holder sidewall 48, and a second step 54 is provided between the bottom wall 50 and the bottom sidewall 32 of the rotor body 12, the purpose of which will be explained in more detail below. Also, a pair of reinforcing flanges 56, 58 (FIG. 3) extend between each cup holder sidewall 48 and the bottom sidewall 32 to help reinforce the rigidity of the tubular cell cup holder 46.

[0031] The rotor body 12 also includes a plurality of tubular cell bore cavities 60, each extending from the upper surface 34 of the top plate 30 toward the bottom wall 50 of a respective cell cup holder 46, such that each tubular cavity 60 opens to the exterior of the rotor body 12 through an opening 62 in the upper surface 34 and is sealed off from the interior space 44 of the rotor body 12 by the side wall 48 and bottom wall 50 of the cup holder 46. As shown, each tubular cavity 60 has a longitudinal axis angled radially outwardly relative to the axis of rotation R in a similar manner as the corresponding cell cup holder 46. In this regard, each tubular cavity 60 and / or the corresponding cell cup holder 46 defines a central longitudinal axis L that is angled relative to the axis of rotation R.

[0032] In various embodiments, each central longitudinal axis L may be angled relative to the axis of rotation R. In various embodiments, the angle may be between about 15 and about 45 degrees. In some embodiments, in applications where increased rotational speed and / or cooling efficiency is desired, the angle may be between about 15 and about 25 degrees. In some embodiments, in applications where increased separation efficiency is desired, the angle may be between about 25 and about 45 degrees. In some embodiments, a lower volumetric capacity uses a higher angle to increase separation. In some embodiments, a higher volumetric capacity uses a lower angle because it may reduce the overall size of the rotor, thereby improving cooling efficiency by reducing frictional forces. In general, a larger angle may increase separation capacity but decrease cooling efficiency, and a smaller angle may decrease separation capacity but increase cooling efficiency.

[0033] Each of the cavities 60 is appropriately sized and shaped to receive at least one of the sample vessels 18 therein for centrifugal rotation of the vessels 18 about the axis of rotation R. A tapered annular recess 64 is provided in the top plate 30 and / or around the periphery of each cavity 60 of each holder 46 generally proximate the respective opening 62. Each recess 64 tapers radially outward from a position distal to the opening 62 to a position proximate the opening 62 to define a shelf 66, the purpose of which is described below. For example, each recess 64 may taper radially outward at an angle between about 3 degrees and about 10 degrees relative to a plane parallel to the respective central longitudinal axis L. In the embodiment shown, eight cell cup holders 46 and corresponding cell hole cavities 60 are provided to receive eight sample vessels 18. However, any suitable number of cell cup holders 46 and / or cell hole cavities 60 may be used.

[0034] The term "tubular" as used herein refers to any suitable cross-sectional shape, including, but not limited to, for example, rounded corners (e.g., elliptical, circular, or conical), quadrilateral, regular polygon, or irregular polygon, or any other suitable shape, and thus, the term is not intended to be limited to the generally circular cross-sectional profile of the exemplary tubular holder 46 and cavity 60 shown in the figures.

[0035] In one embodiment, the rotor body 12, including the top plate 30, the bottom sidewall 32, and / or the holder 46, is constructed from a carbon fiber material. For example, the rotor body 12 may be compression molded from layers of carbon fiber laminate material coated with a resin.

[0036] As best shown in FIGS. 4 and 5 , a cell core or cup 70 is disposed within each of the cavities 60. Each cell cup 70 includes a tubular wall 72 defining a compartment 74 for receiving a respective sample vessel 18 through an opening 76 in the cup 70. In the embodiment shown, a tapered annular projection 78 is provided on the outer periphery of each of the cell cups 70 approximately proximate the cup opening 76. Each projection 78 tapers radially outward from a position distal to the cup opening 76 to a position proximate the cup opening 76 and defines a stop surface 80. For example, each projection 78 may taper radially outward at an angle between about 3 degrees and about 10 degrees relative to the tubular wall 72. The stop surface 80 is configured to operably engage a ledge 66 of a corresponding cavity 60 to help prevent the cell cup 70 from being removed from the cavity 60, such as during centrifugation.

[0037] In one embodiment, the cell cup 70 is constructed of a homogenous material compared to the material of the rotor body 12 (typically a composite material). For example, the cell cup 70 may be constructed of a metallic material such as titanium. Additionally or alternatively, the cell cup 70 may be constructed of a ceramic. The cell cup 70 may be co-molded to the rotor body 12 or may be inserted into the cavity 60 after construction of the rotor body 12. In the latter case, the protrusions 78 may be removed to allow the cell cup 70 to be inserted into the cavity 60 unimpeded.

[0038] The illustrated centrifuge rotor 10 includes eight cavities 60 and respective cell cups 70 for receiving eight sample containers 18, each having a 39 mL capacity, such that the centrifuge rotor 10 has a sample capacity of 8×39 mL. However, the centrifuge rotor 10 may have any other suitable sample capacity, including but not limited to those described below with respect to FIGS. 6 and 7.

[0039] The illustrated pressure plate 14 is generally disc-shaped and, in one embodiment, includes a generally planar upper surface 82, radially inner and outer lower surfaces 84, 86, and a generally smoothly tapered side surface 88. The upper surface 82 and the radially inner lower surface 84 may be spaced apart from one another to define a maximum thickness of the pressure plate 14. For example, the pressure plate 14 may have a maximum thickness of between about 0.25 inches (0.635 cm) and about 1.25 inches (3.175 cm). A tapered bore 90 extends through the pressure plate 14 from the upper surface 82 to the radially inner lower surface 84 for receiving at least a shaft portion of the hub 16, and is configured to be coaxial with the hub 16 such that the bore 90 also defines an axis of rotation R. In the embodiment shown, the bore 90 tapers radially outward from the upper surface 82 to the radially inner lower surface 84. For example, the bore 90 may taper radially outward at an angle between about 3 degrees and about 10 degrees relative to the axis of rotation R. In the embodiment shown, the side surfaces 88 taper radially inward from the upper surface 82 to the radially outer lower surface 86. For example, the side surfaces 88 may taper radially inward at an angle between about 3 degrees and about 10 degrees relative to a plane parallel to the axis of rotation R. The illustrated pressure plate 14 includes an annular shelf 92 ( FIG. 3 ) disposed about the periphery of the upper surface 82 for receiving the bottom of the bottom sidewall 32 of the rotor body 12.

[0040] As best shown in FIG. 3, a plurality of circumferentially spaced recesses 94 are provided in the upper surface 82 of the pressure plate 14, each configured to receive and engage in abutting relation with a respective one of the cup holders 46 of the rotor body 12, such as during high speed rotation of the rotor 10. In this regard, each of the recesses 94 is suitably shaped or configured to contact a lower portion of the respective holder 46, such as the bottom wall 50 and a portion of its sidewall 48. Each of the illustrated recesses 94 includes a contoured bottom surface 96 configured to fully envelop and engage the bottom wall 50 of the respective holder 46, and curved side surfaces 98 configured to engage the sidewalls 48 of the holder 46. For example, the side surfaces 98 may be angled between about 20 degrees and about 25 degrees relative to the axis of rotation R. A first shelf 100 is provided between the bottom surface 96 and the side surface 98 for engaging with the first step 52 of the respective cup holder 46, and a second shelf 102 is provided between the bottom surface 96 and the shelf 92 of the pressure plate 14 for engaging with the second step 54 of the cup holder 46, such that the association between the steps 52, 54 and the respective shelves 100, 102 can aid in positioning and / or maintaining a desired position of the rotor body 12 relative to the pressure plate 14. In the embodiment shown, eight recesses 94 are provided corresponding to the eight holders 46. However, any number of recesses 94 may be provided.

[0041] As best shown in FIGS. 4 and 5 , the radially inner and outer undersides 84, 86 are offset from one another to define an outward step 104. As shown, the radially inner underside 84 is generally flat and the radially outer underside 86 generally curves upwardly in a generally convex manner from the step 104 toward the side 88 of the pressure plate 14. A plurality of circumferentially spaced bores 106 are provided in the radially inner underside 84 of the pressure plate 14, each configured to receive a respective pin 108 for operatively coupling the pressure plate 14 to the hub 16. In one embodiment, three bores 106 may be provided and may be spaced circumferentially from one another by approximately 120 degrees. However, any number of bores 106 may be used at any spacing.

[0042] In one embodiment, the pressure plate 14 is constructed from a carbon fiber material. For example, the pressure plate 14 may be compression molded from layers of resin coated carbon fiber laminate material.

[0043] As best shown in FIGS. 3 and 4 , the pressure plate 14 operably couples to the bottom sidewall 32 of the rotor body 12 and / or the cell cup holder 46 to close the interior space 44 of the rotor 10 and at least partially define the bottom of the rotor 10. In particular, the pressure plate 14 operably couples to the bottom wall 50 of the cup holder 46 to support the cup holder 46 during high speed rotation of the rotor 10, thereby providing structural integrity and minimizing the possibility of failure of the rotor 10. In use, as the rotor 10 rotates, the hub 16 applies torque directly to the pressure plate 14 using the pins 108, and the pressure plate 14 applies torque directly to the cup holder 46 and rotor body 12 via the engagement between the recesses 94 and the bottom of the respective cup holders 46. More specifically, the pressure plate 14 may be the primary or only transfer mechanism of torque from the hub 16 to the cup holder 46 and rotor body 12. To this end, the bond between the pressure plate 14 and the rotor body 12 may be such that the pressure plate 14 exerts pressure against each of the bottom walls 50, thereby providing the necessary support. The substantial contact of the recesses 94 with the bottom of the cup holders 46 facilitates minimizing the potential for high speed rotation-related stress concentrations on the pressure plate 14.

[0044] The bond between the pressure plate 14 and the rotor body 12 may be facilitated by compression molding the pressure plate 14, bottom sidewall 32, and holder 46 together, thereby creating a unitary structure. Those skilled in the art will readily appreciate that the illustrated bond between the pressure plate 14 and the rotor body 12 is exemplary and not intended to be limiting, inasmuch as variations in the type of bond between these components are also contemplated. For example, the pressure plate 14 and the rotor body 12 may additionally or alternatively be bonded together using an adhesive. Such bonds may be further facilitated by stiffeners 24, 26, as described below.

[0045] As best shown in Figures 2, 4 and 5, the pressure ring 110 is disposed on the rotor body 12, and more specifically, on the cell cup holder 46 to help strengthen the rotor body 12. For example, the pressure ring 110 may be press-fitted into the rotor body 12 around the cell cup holder 46, such as against the bottom sidewall 32 of the rotor body 12. The illustrated pressure ring 110 has a generally triangular cross-section and is configured to be coaxial with the hub 16 such that the pressure ring 110 also defines an axis of rotation R. In this regard, the pressure ring 110 includes a radially outer surface 112 and a radially inner surface 114 that intersect each other at one end and are spaced apart from each other by a top surface 116 at the other end. In the embodiment shown, a radius 118 is provided between the radially outer surface 112 and the top surface 116 for a smooth transition between the radially outer surface 112 and the top surface 116. The radially inner surface 114 is inclined at an angle relative to the axis of rotation R in a manner similar to the angle of the bottom sidewall 32 of the rotor body 12 relative to the axis of rotation R, and coincides with the bottom sidewall 32. For example, the radially inner surface 114 may be angled between about 20 degrees and about 25 degrees relative to the axis of rotation R. In this manner, substantially the entire radially inner surface 114 may be capable of operatively engaging the bottom sidewall 32 of the rotor body 12 when the pressure ring 110 is press-fitted into the rotor body 12. As shown, the pressure ring 110 may be configured to be press-fitted into the rotor body 12 at or near a lower portion of the bottom sidewall 32, which may be a location of the rotor body 12 where maximum pressure occurs during centrifugation. In this regard, the pressure ring 110 may define a lower inner diameter that is generally equal to a lower outer diameter of the bottom sidewall 32, and an upper inner diameter that is generally equal to an upper outer diameter of the bottom sidewall 32. In the embodiment shown, the radially outer surface 112 of the pressure ring 110 tapers radially inward from the top surface 116 to an intersection of the outer surface 112 and the inner surface 114 in a manner similar to the tapering of the side surface 88 of the pressure plate 14 for a smooth transition therebetween when the pressure ring 110 is press-fitted into the rotor body 12. For example, the radially outer surface 112 may taper radially inward at an angle between about 3 degrees and about 10 degrees with respect to a plane parallel to the axis of rotation R.

[0046] In one embodiment, the pressure ring 110 is constructed of a homogenous material. The pressure ring 110 may be constructed of a relatively hard material as compared to the material of the rotor body 12 and / or the pressure plate 14. For example, the pressure ring 110 may be constructed of a metallic material, such as titanium. Additionally or alternatively, the pressure ring 110 may be constructed of a ceramic.

[0047] As noted above, in one embodiment, the bond between the pressure plate 14 and the rotor body 12 may be further enhanced by first and / or second reinforcements 24, 26, which may be applied, for example, by wrapping (e.g., helical and / or circular wrapping) one or more strands of high strength fibers, such as a tow or strand of carbon fiber (e.g., resin-coated carbon fiber) around the outer surface of the rotor body 12 and / or pressure plate 14. After compression molding (i.e., heat and pressure are applied), the pressure plate 14 and rotor body 12 become a unitary structure, particularly if the fibers are resin-coated. In certain embodiments, manufacturing the rotor 10 may include curing the resin-coated carbon fiber tow or strand reinforcement such that the strand becomes integral with the rotor body 12 and / or pressure plate 14.

[0048] The illustrated first reinforcement 24 includes a first strand of material 120 wound in a circular shape around at least a portion of the rotor body 12, pressure plate 14, and pressure ring 110. The first strand 120 may be, for example, a carbon fiber strand or filament. The first strand or filament 120 may be a composite material of carbon fiber and resin and / or thermosetting coated fiber that is cured at the end of the winding process to be integrally formed with, for example, the rotor body 12 and pressure plate 14. Alternatively, various other high tensile, high modulus materials may be used in place of carbon fiber, such as synthetic fibers, such as glass fiber, para-aramid fibers (e.g., Kevlar®), thermoplastic filaments, such as ultra-high molecular weight polyethylene, metal wire, or other materials suitable for reinforcing the rotor body 12 and pressure plate 14. Such materials may be used as a single continuous filament or multiple filaments, and many of such materials may be applied with a resin coating that can be cured in a manner similar to the curing of resin-coated carbon fiber. The first reinforcement 24 may comprise a single fiber tow, a multi-fiber tow, or a unidirectional tape in various alternative embodiments.

[0049] In the embodiment shown, particularly in Figure 4, the first strands 120 are wrapped around the first and second outer surfaces 38, 40 of the rotor body 12 along a generally circular reinforcing path. For example, the first strands 120 may be wrapped around the portions of the outer surfaces 38, 40 that remain exposed when the pressure ring 110 is press-fit onto the bottom sidewall 32 of the rotor body 12. The first strands 120 are also wrapped around the radially outer surface 112 of the pressure ring 110 and around the side surface 88 of the pressure plate 14 along the same generally circular reinforcing path.

[0050] The first strand 120 may be wrapped around the rotor body 12, pressure plate 14, and pressure ring 110, for example, by rotating the assembled rotor body 12, pressure plate 14, and pressure ring 110 about the axis of rotation R while applying the first strand 120 along the desired path. The first strand 120 may be repeatedly wrapped around the rotor body 12, pressure plate 14, and pressure ring 110 along the reinforcement path. This repeated wrapping of the strand 120 around the respective surfaces 38, 40, 88, 112 results in multiple layers of material covering the rotor body 12, pressure plate 14, and pressure ring 110, thereby defining the first reinforcement 24. As shown, the first stiffener 24 defines a radially inner surface 122 that may conform to the outer surfaces 38, 40, 88, 112 of the rotor body 12, pressure plate 14, and pressure ring 110, and defines an outer surface 124 that is generally smooth.

[0051] The interaction of the inner surface 122 of the first stiffener 24 with the top surface 116 of the pressure ring 110 may effectively lock the pressure ring 110 relative to the rotor body 12. The interaction of the inner surface 122 of the first stiffener 24 with the tapered first outer surface 38 of the top plate 30, the tapered outer surface 88 of the pressure plate 14, and / or the tapered outer surface 112 of the pressure ring 110 may help prevent or inhibit axial displacement of the first stiffener 24 relative to the rotor body 12, the pressure plate 14, and / or the pressure ring 110, such as during centrifugation. For example, each of the tapered surfaces 38, 88, 112 may prevent or inhibit axial displacement of the first stiffener 24 in the upward direction.

[0052] The illustrated second stiffener 26 includes a second strand of material 130 helically wound around at least a portion of the rotor body 12, pressure plate 14, lid 20, and pressure ring 110. In the illustrated embodiment, the second strand 130 is helically wound around the outer surface 124 of the first stiffener 24, thereby radially spaced from the portions of the rotor body 12, pressure plate 14, and pressure ring 110. The second strand 130 may be, for example, a carbon fiber strand or filament. The second strand or filament 130 may be a composite material of carbon fiber and resin and / or thermosetting coated fiber, which is cured to be integrally formed with the rotor body 12, pressure plate 14, and first stiffener 24, for example, at the end of the winding process. Alternatively, various other high tensile, high modulus materials may be used in place of carbon fiber, such as fiberglass, synthetic fibers such as para-aramid fibers (e.g., Kevlar®), thermoplastic filaments such as ultra-high molecular weight polyethylene, metal wire, or other materials suitable for reinforcing the rotor body 12 and pressure plate 14. Such materials may be used as single continuous filaments or multiple filaments, and many such materials can be applied with a resin coating that can be cured in a manner similar to the curing of resin-coated carbon fiber. The second reinforcement 26 may include a single fiber taw, multiple fiber taw, or unidirectional tape in various alternative embodiments.

[0053] In the embodiment shown, the second strand 130 is wound around the outer surface 124 of the first stiffener 24 along a generally helical reinforcing path. The second strand 130 is also wound around the outward step 104 of the pressure plate 14 from the radially outer lower surface 86 of the pressure plate 14 along the same generally helical reinforcing path, and around at least a portion of the lid 20 along the same generally helical reinforcing path. The lid 20 is removably mounted on the rotor body 12 and the second stiffener 26, as described below. The outward step 104 of the pressure plate 14 is disposed radially inward of the central longitudinal axis L of the cell cup holder 46, such that the second strand 130 extends radially inward along the lower surface 86 of the pressure plate 14 relative to the central longitudinal axis L of the cell cup holder 46. Additionally, the outward step 104 of the pressure plate 14 is disposed radially inward relative to the bottom wall 50 of the cell cup holder 46 such that the second strands 130 also extend radially inward along the underside 86 of the pressure plate 14 relative to the bottom wall 50 of the cell cup holder 46. By extending radially inward relative to the bottom wall 50 of the cell cup holder 46, the second stiffener 26 can further resist axially generated centrifugal forces (or components thereof) as described in the disclosure of U.S. Patent No. 8,323,169, incorporated by reference above.

[0054] The second strand 130 may be wrapped around the pressure plate 14, lid 20, and first stiffener 24, for example, by rotating the assembled rotor body 12, pressure plate 14, lid 20, and first stiffener 24 about the axis of rotation R while applying the strand 130 along a desired path. The second strand 130 may be repeatedly wrapped around the pressure plate 14, lid 20, and first stiffener 24 along the stiffening path. This repeated wrapping of the strand 130 results in multiple layers of material covering the pressure plate 14, lid 20, and first stiffener 24, thereby defining the second stiffener 26. In one embodiment, the second strand 130 may be applied in a manner similar to that described in U.S. Pat. No. 8,323,169, which is incorporated herein by reference in its entirety.

[0055] The illustrated rotor hub 16 includes an elongated shaft 140 extending axially from a head 142. The shaft 140 is sized and shaped to extend through and fit snugly between the bores 42, 90 of the rotor body 12 and pressure plate 14, and includes a threaded end 144 distal from the head 142 and a tapered end 146 proximate the head 142. The threaded end 144 is configured to threadably engage with the lid screws 22 to removably couple the lid 20 to the rotor hub 16 on the rotor body 12. The tapered end 146 tapers radially outwardly toward the head 142 to match the taper of the bore 90 of the pressure plate 14, such that interaction between the tapered end 146 and the tapered bore 90 can aid in removably securing the rotor hub 16 to the pressure plate 14. For example, the tapered end 146 may taper radially outwardly at an angle relative to the axis of rotation R between about 3 degrees and about 10 degrees.

[0056] The head 142 of the rotor hub 16 includes a plurality of circumferentially spaced threaded holes 148, each configured to threadably receive one of the pins 108 for operably coupling the pressure plate 14 to the hub 16. In the embodiment shown, three threaded holes 148 are provided, spaced approximately 120 degrees circumferentially from one another to correspond to the bores 106 of the pressure plate 14. However, any suitable number of holes 148 may be used at any suitable interval. Two or more blind bores 150 are provided in the underside of the rotor hub 16 for receiving respective pins of a centrifuge spindle (not shown) to operably couple the rotor hub 16 to the centrifuge spindle. Also, a central recess 152 is provided in the underside of the rotor hub 16 to receive a portion of the centrifuge spindle, such as to help stabilize the rotor hub 16 during rotation. In the embodiment shown, the head 142 of the rotor hub 16 is disposed radially inwardly relative to the outward step 104 of the pressure plate 14, and the head 142 is disposed radially inwardly relative to the second stiffener 26 and spaced therefrom.

[0057] In one embodiment, rotor hub 16 is constructed from a relatively hard material as compared to the material of rotor body 12 and / or pressure plate 14. For example, rotor hub 16 may be constructed from a metallic material, such as titanium.

[0058] The illustrated lid 20 is generally disc-shaped and includes an upper surface 160, a lower surface 162, and an annular flange 164 defining a peripheral recess 166 for receiving a portion of the second stiffener 26. The lower surface 162 may be generally flat and have generally similar cross dimensions as the upper surface 34 of the top plate 30 of the rotor body 12 such that substantially the entire upper surface 34 of the top plate 30 can operably engage the lower surface 162 of the lid 20 when the lid 20 is removably coupled to the rotor hub 16 on the rotor body 12. A bore 168 extends through the lid 20 from the upper surface 160 to the lower surface 162 for receiving at least a portion of the hub 16, such as the axle 140.

[0059] First and second annular grooves 170, 172 are provided in the lower surface 162 for receiving first and second O-rings 174, 176, respectively. As shown, the first and second annular grooves 170, 172 and the first and second O-rings 174, 176, respectively, may have a generally rectangular cross-section. The first and second annular grooves 170, 172 are radially spaced apart from one another by a distance greater than the intersection dimension of the opening 62 in the upper surface 34 of the top plate 30 of the rotor body 12. For example, the first annular groove 170 may be configured to be radially inward of the opening 62 and the second annular groove 172 may be configured to be radially outward of the opening 62 when the lid 20 is removably coupled to the rotor hub 16 on the rotor body 12. In this manner, the O-rings 174, 176 may be able to provide a fluid-tight seal between the lid 20 and the rotor body 12 both radially inward and radially outward of the opening 62. The interface between the flat lower surface 162 of the lid 20 and the flat upper surface 34 of the top plate 30 can help provide such a fluid-tight seal to prevent sample from inadvertently leaking from the respective sample vessel 18 as a result of rotation, evaporation, or other events that may cause at least a portion of the sample to migrate towards the lid 20.

[0060] In one embodiment, the lid 20 is constructed from a carbon fiber material. For example, the lid 20 may be compression molded from layers of resin-coated carbon fiber laminate material.

[0061] Once the rotor body 12 and pressure plate 14 are attached to the rotor hub 16, the lid 20 of the rotor 10 may be removably coupled to the rotor hub 16 on the rotor body 12 using the lid screw 22. In this regard, the lid screw 22 includes a threaded hole 178 that threadably engages the threaded end 144 of the shaft 140 of the rotor hub 16. The illustrated lid screw 22 also includes a lower annular flange 180 configured to cover at least a central portion of the lid 20. The lid screw 22 may be tightened against the lid 20 using, for example, a tool rod (not shown). Once removably coupled to the rotor hub 16 on the rotor body 12 using the lid screw 22, the lid 20 blocks access to the sample vessels 18 held in the cavities 60, such as during high speed spinning. The centrifuge spindle may then be actuated to drive the rotor 10 into high speed centrifugal rotation.

[0062] In one embodiment, for example, to help position and / or maintain a desired position of the rotor body 12 relative to the pressure plate 14, the rotor body 12 and pressure plate 14 may be attached to the rotor hub 16, or a tool similar to the rotor hub 16, during compression molding of the rotor body 12 and / or pressure plate 14 and / or during winding of the first and / or second stiffeners 24, 26. Similarly, the lid 20 may be removably coupled to the rotor body 12 (or a tool) during at least winding of the second stiffener 26, to help ensure that a portion of the second stiffener 26 is received within the peripheral recess 166 of the lid 20. During centrifugation, the first and second windings 24, 26 may contribute to the strength of the rotor 10, thereby helping to maintain the structural integrity of the rotor 10 under high stresses and strains. For example, the first stiffener 24 may help counteract primarily radially outward forces, while the second stiffener 26 may help counteract both radially outward forces and axially downward forces.

[0063] The pressure ring 110 may also contribute to the strength of the rotor 10 during centrifugation. For example, the pressure ring 110 may help evenly distribute forces directed both radially and axially outward from the rotor body 12 to the first stiffener 24, thereby reducing or eliminating stress points.

[0064] Turning now to FIG. 6, where like numerals represent like features, another exemplary centrifuge rotor 10a according to another embodiment of the present invention is shown. The rotor 10a includes a rotor body 12a and a pressure plate 14a fixedly coupled to one another and is symmetrical about an axis of rotation R defined by a rotor hub 16a about which samples contained in sample containers 18a disposed in the rotor body 12a may be centrifugally rotated. The rotor 10a also includes a lid 20a removably coupled to the rotor hub 16a on the rotor body 12a using lid screws 22a, for example, to help retain the sample containers 18a within the rotor body 12a during rotation thereof. Similar to the embodiment shown in FIGS. 1-5, first and second elongated stiffeners 24a, 26a extend continuously around at least a portion of the rotor body 12a and the pressure plate 14a, respectively.

[0065] The main difference between the centrifuge rotor 10 shown in Figures 1-5 and the centrifuge rotor 10a shown in Figure 6 is the sample capacity, more specifically the size and number of the cavities 60, 60a, the respective cell cups 70, 70a, and the sample vessels 18, 18a. In this regard, the illustrated centrifuge rotor 10a has a sample capacity of 14 x 13.5 mL. That is, the centrifuge rotor 10a includes 14 cavities 60a and cell cups 70a, respectively, for receiving 14 sample vessels 18a, each having a capacity of 13.5 mL.

[0066] Various other features of the centrifuge rotor 10a are generally similar to those described above with respect to Figures 1-5 and will not be repeated here for the sake of brevity.

[0067] Turning now to FIG. 7, where like numerals represent like features, another exemplary centrifuge rotor 10b according to another embodiment of the present invention is shown. The rotor 10b includes a rotor body 12b and a pressure plate 14b fixedly coupled to one another and is symmetrical about an axis of rotation R defined by a rotor hub 16b about which samples contained in sample containers 18b disposed in the rotor body 12b may be centrifugally rotated. The rotor 10b also includes a lid 20b removably coupled to the rotor hub 16b on the rotor body 12b using lid screws 22b, for example, to help retain the sample containers 18b within the rotor body 12b during rotation thereof. Similar to the embodiment shown in FIGS. 1-5, first and second elongated stiffeners 24b, 26b extend continuously around at least a portion of the rotor body 12b and the pressure plate 14b, respectively.

[0068] The main difference between the centrifuge rotor 10 shown in Figures 1-5 and the centrifuge rotor 10b shown in Figure 7 is the sample capacity, more specifically the size of the cavities 60, 60b, the respective cell cups 70, 70b, and the sample containers 18, 18b. In this regard, the illustrated centrifuge rotor 10b has a sample capacity of 8 x 100 mL. That is, the centrifuge rotor 10b includes eight cavities 60b and cell cups 70b, respectively, for receiving eight sample containers 18b, each having a capacity of 100 mL.

[0069] Various other features of centrifuge rotor 10b are generally similar to those described above with respect to Figures 1-5 and will not be repeated here for the sake of brevity.

[0070] Turning now to FIG. 8, an exemplary method for manufacturing a centrifuge rotor 10, 10a, 10b is provided. In step 201, the rotor body 12, 12a, 12b is constructed. For example, the rotor body 12, 12a, 12b may be compression molded from layers of resin-coated carbon fiber laminate material. In step 202, each of the cell cores or cups 70, 70a, 70b is placed into one of the cavities 60, 60a, 60b of the rotor body 12, 12a, 12b. The cell cups 70, 70a, 70b may be co-molded to the rotor body 12, 12a, 12b (e.g., during step 201) or may be inserted into the cavities 60, 60a, 60b after construction of the rotor body 12, 12a, 12b. In step 203, the pressure plates 14, 14a, 14b are constructed. For example, the pressure plates 14, 14a, 14b may be compression molded from layers of resin coated carbon fiber laminate material.

[0071] In step 204, the rotor body 12, 12a, 12b is placed on the pressure plate 14, 14a, 14b. During step 204, the rotor body 12, 12a, 12b and pressure plate 14, 14a, 14b may be attached to the rotor hub 16, 16a, 16b, or a tool similar to the rotor hub 16, 16a, 16b, for example, to help position and / or maintain a desired position of the rotor body 12, 12a, 12b relative to the pressure plate 14, 14a, 14b. In one embodiment, step 204 may include coupling the rotor body 12, 12a, 12b and pressure plate 14, 14a, 14b together. For example, the pressure plate 14, 14a, 14b and the bottom sidewall 32, 32a, 32b of the rotor body 12, 12a, 12b and the holder 46, 46a, 46b can be compression molded together, thereby resulting in a unitary structure. Additionally or alternatively, the rotor body 12, 12a, 12b and the pressure plate 14, 14a, 14b can be bonded together using an adhesive. For example, the rotor body 12, 12a, 12b and the pressure plate 14, 14a, 14b can be first bonded together using an adhesive before the rotor body 12, 12a, 12b and the pressure plate 14, 14a, 14b are compression molded together. Alternatively, the rotor body 12, 12a, 12b and the pressure plate 14, 14a, 14b can be compression molded together during a later step, as described below.

[0072] In step 205, the pressure ring 110, 110a, 110b is placed on the rotor body 12, 12a, 12b. For example, the pressure ring 110, 110a, 110b may be press-fitted into the rotor body 12, 12a, 12b around the cell cup holder 46, 46a, 46b, such as against the bottom sidewall 32, 32a, 32b of the rotor body 12, 12a, 12b.

[0073] In step 206, a first reinforcement 24, 24a, 24b is applied to at least the rotor body 12, 12a, 12b and the pressure plate 14, 14a, 14b. For example, a first strand of material 120, 120a, 120b may be wrapped in a circular shape around at least a portion of the rotor body 12, 12a, 12b, the pressure plate 14, 14a, 14b, and the pressure ring 110, 110a, 110b. During step 206, the rotor body 12, 12a, 12b and the pressure plate 14, 14a, 14b may be attached to the rotor hub 16, 16a, 16b, or a tool similar to the rotor hub 16, 16a, 16b, for example, to help position and / or maintain a desired position of the rotor body 12, 12a, 12b relative to the pressure plate 14, 14a, 14b. In one embodiment, step 206 may include curing the first strands 120, 120a, 120b after the winding process to integrally form the rotor body 12, 12a, 12b and the pressure plate 14, 14a, 14b. Such curing may also include compression molding the rotor body 12, 12a, 12b and the pressure plate 14, 14a, 14b together. Alternatively, the first strands 120, 120a, 120b may be cured during a later step, as described below.

[0074] In step 207, the second stiffeners 26, 26a, 26b are applied to at least the pressure plate 14, 14a, 14b and the first stiffeners 24, 24a, 24b. For example, the second strands of material 130, 130a, 130b may be spirally wrapped around at least a portion of the rotor body 12, 12a, 12b, pressure plate 14, 14a, 14b, lid 20, 20a, 20b, and pressure ring 110, 110a, 110b. During step 207, the rotor body 12, 12a, 12b and pressure plate 14, 14a, 14b may be attached to the rotor hub 16, 16a, 16b, or to a tool similar to the rotor hub 16, 16a, 16b, for example, to help position and / or maintain a desired position of the rotor body 12, 12a, 12b relative to the pressure plate 14, 14a, 14b. Similarly, the lid 20, 20a, 20b may be removably coupled to the rotor hub 16, 16a, 16b (or to a tool) during step 207 to help ensure that a portion of the second stiffener 26, 26a, 26b is received within the peripheral recess 166, 166a, 166b of the lid 20, 20a, 20b. In one embodiment, step 207 may include curing the second strands 130, 130a, 130b after the winding process to integrally form the rotor body 12, 12a, 12b, the pressure plate 14, 14a, 14b, and the first stiffeners 24, 24a, 24b. Such curing may also include curing the first strands 120, 120a, 120b and / or compression molding the rotor body 12, 12a, 12b and the pressure plate 14, 14a, 14b together.

[0075] In step 208, the rotor hub 16, 16a, 16b is operably coupled to the pressure plate 14, 14a, 14b. For example, each of the pins 108, 108a, 108b may be threaded through a respective one of the threaded holes 148, 148a, 148b and inserted into the corresponding bore 106, 106a, 106b of the pressure plate 14, 14a, 14b. As noted above, step 208 may be performed before or during one or more of steps 204, 206, or 207.

[0076] In step 209, the lid 20, 20a, 20b is removably coupled to the rotor hub 16, 16a, 16b. For example, the lid 20, 20a, 20b may be removably coupled to the rotor hub 16, 16a, 16b on the rotor body 12, 12a, 12b using lid screws 22, 22a, 22b, which may be tightened against the lid 20, 20a, 20b using a tool rod. Typically, the lid 20, 20a, 20b is coupled onto the rotor body 12, 12a, 12b only after the sample in the sample container has been inserted into the cavity 60, 60a, 60b.

[0077] The assembled centrifuge rotor 10, 10a, 10b may then be driven into high speed centrifugal rotation using the centrifuge spindle. After centrifugation, the lids 20, 20a, 20b are removed from the rotor bodies 12, 12a, 12b and the samples in the sample vessels are removed from the cavities 60, 60a, 60b.

[0078] Various aspects according to the principles of the present invention have been illustrated by the description of various embodiments, and although the embodiments have been described in considerable detail, they are not intended to limit the scope of the invention to such detail or in any way. The various features shown and described herein may be used alone or in any combination. Additional advantages and modifications will be readily apparent to those skilled in the art. Thus, the invention in its broadest aspects is not limited to the specific details, representative apparatus and methods, and illustrative examples shown and described. Thus, departures may be made from such details without departing from the scope of the general inventive concept.

[0079] The following additional note is added: (Supplementary Note 1) A rotor body having an upper surface and a plurality of tubular cavities extending from the upper surface to a respective bottom wall, each cavity configured to receive a sample vessel therein; a pressure plate operably coupled to the bottom wall and configured to transmit torque to the bottom wall; Equipped with A fixed angle centrifuge rotor, wherein the pressure plate is directly coupled to a rotor hub and configured to receive torque directly from the rotor hub. (Appendix 2) The fixed-angle centrifuge rotor of Appendix 1, wherein the pressure plate includes an upper surface and a plurality of recesses spaced apart on the upper surface, each recess including a bottom surface, the bottom surfaces completely enveloping and engaging the bottom wall. (Appendix 3) The fixed-angle centrifuge rotor of appendix 1 or 2, wherein the pressure plate includes a lower surface and a plurality of bores spaced apart from one another on the lower surface, the bores configured to receive respective pins for directly coupling the pressure plate to the rotor hub. (Appendix 4) The fixed-angle centrifuge rotor of appendix 1 or 2, wherein the pressure plate includes a central bore configured to receive a shaft portion of the rotor hub, the central bore being tapered. 5. The fixed-angle centrifuge rotor of claim 1, wherein the pressure plate includes an outer side, the outer side being tapered. (Supplementary Note 6) A first elongated reinforcement member extending around at least one outer surface of the rotor body and at least one outer surface of the pressure plate along a first path; a second elongated stiffener extending around an outer surface of the first elongated stiffener along a second path; 3. The fixed-angle centrifuge rotor of claim 1 or 2, further comprising: (Appendix 7) The fixed-angle centrifuge rotor of Appendices 6, wherein the first path is circular. (Appendix 8) The fixed-angle centrifuge rotor of Appendices 7, wherein the second path is spiral. (Appendix 9) The fixed-angle centrifuge rotor of Appendix 6, wherein the rotor body includes an outer side, the outer side being tapered, and the first elongated reinforcement defines an inner surface conforming to the outer side. (Supplementary Note 10) The fixed-angle centrifuge rotor of Supplementary Note 6, wherein the pressure plate includes an outer side that is tapered, and the first elongated reinforcement defines an inner surface that conforms to the outer side. (Supplementary Note 11) The fixed-angle centrifuge rotor of Supplementary Note 1, further comprising an elongated stiffener extending between a first location radially outward relative to at least one outer surface of the rotor body and a second location radially inward relative to the bottom wall beneath a portion of the pressure plate. (Appendix 12) The fixed-angle centrifuge rotor of appendix 1 or 2, further comprising a lid having a planar lower surface, the rotor body including a planar upper surface that engages with the planar lower surface. 13. The fixed-angle centrifuge rotor of claim 12, wherein at least one of the planar lower surface of the lid or the planar upper surface of the rotor body includes a pair of annular grooves configured to receive a pair of O-rings. 14. The fixed-angle centrifuge rotor of claim 1 or 2, further comprising a pressure ring extending around an outer surface of the rotor body and press-fitted into the rotor body. 15. The fixed-angle centrifuge rotor of claim 14, further comprising a first elongated stiffener extending along a first path around at least one outer surface of the rotor body and at least one outer surface of the pressure ring. 16. The fixed-angle centrifuge rotor of claim 15, further comprising a second elongated stiffener extending around an outer surface of the first elongated stiffener along a second path. 17. The fixed-angle centrifuge rotor of claim 16, wherein the first path is circular and the second path is spiral. (Supplementary Note 18) The fixed-angle centrifuge rotor of Supplementary Note 14, wherein the pressure ring is made of at least one of a metallic material or a ceramic material. (Appendix 19) A method of manufacturing a fixed-angle centrifuge rotor, comprising the steps of: providing a rotor body including a plurality of tubular cavities, each cavity configured to receive a sample vessel therein; disposing a plurality of cell cups into the plurality of cavities, each of the cell cups being received in a respective one of the cavities; Providing a pressure plate; placing the rotor body on the pressure plate; disposing a pressure ring on the rotor body; applying a first stiffener to at least the rotor body and the pressure plate; applying a second stiffener to at least the pressure plate and the first stiffener; 2. A method for manufacturing a fixed angle centrifuge rotor, comprising: (Supplementary Note 20) A fixed-angle centrifuge rotor, comprising: a rotor body having a top surface and a plurality of tubular cavities extending from the top surface to a respective bottom wall, each cavity configured to receive a sample vessel therein; a pressure plate operably coupled to the bottom wall and configured to transmit torque to the bottom wall; a first elongated stiffener extending along a first path around at least one outer surface of the rotor body and at least one outer surface of the pressure plate; a second elongated stiffener extending around an outer surface of the first elongated stiffener along a second path; A fixed angle centrifuge rotor comprising: (Supplementary Note 21) A fixed-angle centrifuge rotor, comprising: a rotor body having a top surface and a plurality of tubular cavities extending from the top surface to a respective bottom wall, each cavity configured to receive a sample vessel therein; a pressure plate operably coupled to the bottom wall and configured to transmit torque to the bottom wall; an elongated stiffener extending between a first location radially outward relative to at least one outer surface of the rotor body and a second location radially inward relative to the bottom wall beneath a portion of the pressure plate; A fixed angle centrifuge rotor comprising: (Supplementary Note 22) A fixed-angle centrifuge rotor, comprising: a rotor body having a top surface and a plurality of tubular cavities extending from the top surface to a respective bottom wall, each cavity configured to receive a sample vessel therein; a pressure ring extending around an outer surface of the rotor body and press-fitted into the rotor body; A fixed angle centrifuge rotor comprising:

Claims

1. a rotor body having a top surface and a plurality of tubular cavities extending from the top surface to a respective bottom wall, each tubular cavity configured to receive a sample vessel therein; a pressure plate operably coupled to the bottom wall and configured to transmit torque to the bottom wall; a pressure ring extending around an outer surface of the rotor body and press-fitted into the rotor body; a first elongated stiffener extending along a first path around at least one outer surface of the rotor body and at least one outer surface of the pressure plate; a second elongated stiffener extending around an outer surface of the first elongated stiffener along a second path; A fixed angle centrifuge rotor comprising:

2. A fixed-angle centrifuge rotor as described in claim 1, wherein the pressure plate is directly coupled to the rotor hub and configured to receive torque directly from the rotor hub.

3. A fixed-angle centrifuge rotor as described in any one of claims 1 or 2, having a plurality of cell cups in the plurality of tubular cavities, each of the cell cups being received in one of the respective tubular cavities.

4. A fixed-angle centrifuge rotor as described in claim 1 or 2, wherein the pressure plate includes an upper surface and a plurality of recesses spaced apart on the upper surface, each recess including a bottom surface, the bottom surfaces completely enveloping and engaging the bottom wall.

5. A fixed angle centrifuge rotor as described in claim 2 or claim 4 citing claim 2, wherein the pressure plate includes a central bore configured to receive a shaft portion of the rotor hub, the central bore being tapered.

6. A fixed angle centrifuge rotor as described in claim 1 or 2, wherein the pressure plate includes an outer side, the outer side being tapered.

7. A fixed-angle centrifuge rotor as described in claim 1 or 2, wherein the first path is circular.

8. The fixed angle centrifuge rotor of claim 7, wherein the second path is spiral.

9. A fixed angle centrifuge rotor as described in claim 1 or 2, wherein the rotor body includes an outer side, the outer side being tapered, and the first elongated reinforcement member defines an inner surface that coincides with the outer side.

10. A fixed angle centrifuge rotor as described in claim 1 or 2, wherein the pressure plate includes an outer side that is tapered, and the first elongated stiffener defines an inner surface that coincides with the outer side.

11. A fixed-angle centrifuge rotor as described in claim 1 or 2, wherein the first elongated reinforcement extends along the first path around at least one outer surface of the rotor body and at least one outer surface of the pressure ring.

12. A fixed-angle centrifuge rotor as described in claim 1 or 2, wherein the first path is circular and the second path is spiral.

13. A fixed-angle centrifuge rotor as described in claim 1 or 2, wherein the pressure ring is constructed of at least one of a metallic material or a ceramic material.

14. A method for manufacturing a fixed-angle centrifuge rotor, comprising the steps of: providing a rotor body including a plurality of tubular cavities, each tubular cavity configured to receive a sample vessel therein; disposing a plurality of cell cups within the plurality of tubular cavities, each of the cell cups being received in a respective one of the tubular cavities; Providing a pressure plate; placing the rotor body on the pressure plate; disposing a pressure ring on the rotor body; applying a first stiffener to at least the rotor body and the pressure plate; applying a second stiffener to at least the pressure plate and the first stiffener; 2. A method for manufacturing a fixed angle centrifuge rotor, comprising:

Images