Continuous Bioprocess Centrifuge Rotor

Abstract

A rotor assembly (10, 150, 270, 310) and a method of using the rotor assembly (10, 150, 270, 310). The rotor assembly (10, 150, 270, 310) includes a bioprocess bag (48), a drum (46) that receives the lower part of the bag (48), and a pressure ring (50). A holder (54, 182) couples the upper part of the bag (48) to the pressure ring (50). The pressure ring (50) is coupled to the drum (46) to define an interior space that accommodates the bag (48). A liquid transfer assembly (35, 178, 272) passes through an opening in the holder (54, 182) and can add and remove liquid from the bag (48) without removing the rotor (16, 154) from the centrifuge. A bearing assembly (190) in the holder (54, 182) couples the liquid transport assembly (35, 178, 272) to the rotor (16, 154) and allows the liquid transport assembly (35, 178, 272) to remain stationary while the rotor (16, 154) rotates about it. One or more seal assemblies (276, 312) provide a fluid-tight seal against an outer portion of the liquid transport assembly (35, 178, 272) to prevent fluid from leaking from the bag (48) during centrifugation.

Description

[Technical Field]

[0001] The present invention relates generally to centrifuge rotors, and more particularly to rotors configured for continuous processing of biological suspensions within a centrifuge. [Background technology]

[0002] Bioreactors and fermenters are used to grow biological suspensions containing cells or microorganisms suspended in a liquid medium. Once the biological suspension has grown sufficiently, it is typically separated into liquid and solid components. The separated components are recovered for further analysis or use. Centrifugation is a common technique for separating biological components such as cells, organelles, and biopolymers, including proteins, nucleic acids, lipids, and carbohydrates, dispersed in a biological suspension.

[0003] Centrifugation typically involves dispensing a volume of suspension from a bioreactor or fermenter into a processing vessel such as a bottle or bag. The vessel is then closed and spun in a centrifuge. The centrifugal force generated by the spinning rotor in the centrifuge causes solids in the suspension to settle, forming a mostly solid pellet toward the bottom of the vessel. A supernatant containing liquids with a lower density than the pellet collects in the vessel above the pellet. In other cases, a density gradient may form in the suspension, forming overlapping isopycnic layers of liquids containing solids of similar density. In either case, once the supernatant and pellet or isopycnic layers have formed, the separated components can be decanted by pouring, pumping, or otherwise removing each component from the vessel.

[0004] Conventional centrifugation processes have many drawbacks. For example, to increase throughput, it is typically desirable for the container to hold as much suspension as possible. However, as the size of the container increases, it becomes more difficult for an operator to load and unload the container from the centrifuge. Increasing the number of containers loaded into the centrifuge also improves throughput. However, a larger number of containers increases the time it takes an operator to load and unload each batch of containers into the centrifuge.

[0005] Another problem with centrifugation is how to remove the various separated components without affecting the others. This problem can be exacerbated when the containers are large or difficult to remove from the centrifuge due to excessive jostling, which can cause the separated components to remix.

[0006] Therefore, there is a need for improved methods and systems for centrifugation of biological suspensions. Summary of the Invention

[0007] The present invention overcomes the aforementioned and other shortcomings and drawbacks of previously known centrifuge rotors for use in centrifugation of biological suspensions. While the present invention will be discussed in connection with specific embodiments, it will be understood that the invention is not limited to these embodiments.

[0008] In one embodiment of the present invention, a rotor assembly for centrifuging a liquid culture medium is provided. The rotor assembly includes a bioprocess bag, a drum, and a holder. The bioprocess bag has a lower portion and an upper portion. The upper portion of the bioprocess bag includes an axially aligned neck connected to the lower portion of the bioprocess bag and a radially aligned skirt extending outward from the axially aligned neck. The drum includes a first base having an outer rim and a first circumferential wall extending upward from the outer rim. The first circumferential wall includes a first outer surface and a first inner surface, the first inner surface defining a first opening for receiving the lower portion of the bioprocess bag. A pressure ring includes a first radially aligned flange and a second circumferential wall. The radially aligned first flange includes a first upper surface, an outer edge, and an inner edge defining the second opening. The second circumferential wall extends downward from the outer edge and has a second inner surface that engages the first outer surface of the first circumferential wall of the drum. The holder includes a third circumferential wall having an outwardly facing surface and a radially aligned second flange having a first lower surface. The second radially aligned flange extends outward from the top of the third circumferential wall, and at least one of the outwardly facing surface and the first lower surface operably couples the top of the bioprocess bag to the pressure ring.

[0009] In one aspect of the invention, the rotor assembly can further include a compression ring having a second upper surface with a recessed annulus. The recessed annulus can be open on an axial side of the compression ring and define a radially aligned circumferential channel with the first lower surface of the second radially aligned flange of the holder. The radially aligned circumferential channel can be configured to receive at least a portion of the radially aligned skirt of the bioprocess bag.

[0010] In another aspect of the invention, the second radially aligned flange and the compression ring of the holder may each include a plurality of through holes, and the rotor assembly may further include a plurality of retaining bolts and a retaining ring having a plurality of threaded holes, each threaded hole configured to receive a respective one of the retaining bolts. Each retaining bolt may pass through a respective through hole of the second radially aligned flange and the compression ring, and the compression ring may be subjected to a compressive force by the second radially aligned flange and the retaining ring in response to tightening of the retaining bolts.

[0011] In another aspect of the invention, the pressure ring may include a circumferential ridge projecting upwardly from a first upper surface of the first radially aligned flange and may include an axially aligned inwardly facing surface configured to center the retaining ring about a second opening defined by an inner edge of the pressure ring.

[0012] In another aspect of the invention, the drum may include a plurality of axially aligned baffles.

[0013] In another aspect of the invention, the lower portion of the bioprocess bag may include a plurality of internal pockets and a plurality of external pockets each disposed between two adjacent internal pockets, and each of the external pockets may be configured to engage with a respective axially aligned baffle of the drum.

[0014] In another aspect of the invention, each of the axially aligned baffles may include a hollow, the first base may include a second lower surface having a third opening into the hollow of each axially aligned baffle, and the rotor assembly may further include a torque transfer module including a third upper surface having a plurality of protrusions each configured to engage with a respective third opening in the second lower surface of the first base.

[0015] In another aspect of the invention, the rotor assembly may further comprise a housing including a cover and a second base configured to receive the cover, and the bioprocess bag, drum, pressure ring, and holder may comprise a rotor that rotates within the housing.

[0016] In another aspect of the invention, the third circumferential wall of the holder can include an inwardly facing surface defining a fourth opening, and the rotor assembly can further include a decant assembly passing through the cover and the fourth opening. The decant assembly can have an input port through which the first liquid medium is removed from the bioprocess bag. The first base can include a fourth upper surface having an upwardly facing bowl shape defining a collection area proximate the rotational axis of the rotor, and the input port of the decant assembly can be disposed proximate to the collection area.

[0017] In another aspect of the invention, the rotor assembly can further include a feed assembly passing through the cover and the fourth opening. The feed assembly can include a feed assembly output port through which the second liquid medium is provided to the bioprocess bag.

[0018] In another embodiment of the invention, the first liquid medium is a supernatant and the second liquid medium is a suspension.

[0019] In another aspect of the invention, the feeding assembly can further include a feeding assembly input port and a feeding tube having a third inner surface with a first diameter, and the decant assembly can include a decant tube having a second outer surface with a second diameter smaller than the first diameter and passing longitudinally through the feeding tube. The first diameter can be greater than the second diameter along at least a portion of the decant tube such that the decant tube and the feeding tube define an annular channel between the second outer surface of the decant tube and the third inner surface of the feeding tube. The annular channel can fluidly couple the feeding assembly input port to the feeding assembly output port.

[0020] In another aspect of the invention, the rotor assembly may further comprise a bearing assembly and a fluid transfer assembly that passes through the cover and bearing assembly and includes a first port through which a first liquid medium is removed from the bioprocess bag and a second port through which a second liquid medium is provided to the bioprocess bag.

[0021] In another aspect of the invention, the holder can include a lower section having a first cylindrical ring and an upper section including a second cylindrical ring, The first and second cylindrical rings can define a central cavity that retains the bearing assembly when the lower section is coupled to the upper section.

[0022] In another aspect of the invention, a bearing assembly may include an upper bearing having a first inner ring with a first bore, a lower bearing having a second inner ring with a second bore, and a cylindrical spacer that positions the upper bearing perpendicular to the lower bearing such that the first bore and the second bore couple the bearing assembly to a liquid transport assembly.

[0023] In another aspect of the invention, the rotor assembly can further include a sealed bearing having a fifth upper surface and a third lower surface, the sealed bearing being coupled to the cover of the housing via the fifth upper surface and being in rotational contact with the holder via the third lower surface.

[0024] In another aspect of the invention, the rotor assembly may further include a seal drive hub having a third outer surface and a fourth lower surface, and the seal drive hub may be coupled to the cover of the housing via the third outer surface and may be coupled to the fifth upper surface by the fourth lower surface.

[0025] In another aspect of the invention, the fourth lower surface can include one or more protrusions and the fifth upper surface can include one or more notches, each of the protrusions being capable of engaging a respective notch, thereby preventing the seal bearing from rotating relative to the seal drive hub.

[0026] In another aspect of the invention, the seal drive hub may further include one or more heat pipes configured to conduct heat away from the seal bearing.

[0027] In another aspect of the invention, the cover of the housing may include a first central hole, and the rotor assembly may further include a torque retaining hub coupling the seal drive hub to the first central hole.

[0028] In another aspect of the invention, the torque-carrying hub can include a second central hole having a non-circular shape, and a third outer surface of the seal drive hub can have a non-circular shape and be configured to engage with the second central hole of the torque-carrying hub, such that the non-circular shape can prevent the seal drive hub from rotating relative to the torque-carrying hub.

[0029] In another aspect of the invention, the seal drive hub can include a threaded bore, and the liquid transport assembly can include an integral collar having a fourth outer surface with a threaded portion configured for threaded engagement with the threaded bore of the seal drive hub, and the liquid transport assembly can be coupled to the cover of the housing by the seal drive hub.

[0030] In another aspect of the invention, the liquid transport assembly can include an integral collar having a fourth outer surface with a smooth portion, the seal bearing can include an inner groove, and the rotor assembly can further include a resilient member disposed in the inner groove of the seal bearing that provides a fluid-tight seal between the seal bearing and the smooth portion of the fourth outer surface of the integral collar of the liquid transport assembly.

[0031] In another aspect of the invention, the holder can include a first central opening through which the liquid transport assembly passes, and the rotor assembly can further include a seal bearing including a first inner groove and a second upper surface in rotational contact with the holder, and a first elastic member disposed in the first inner groove of the seal bearing that couples the seal bearing to the liquid transport assembly.

[0032] In another aspect of the invention, the holder can include a lower plate coupled to a lower portion of the third circumferential wall, with a central opening in the lower plate.

[0033] In another aspect of the invention, the rotor assembly may further include a second resilient member configured to bias the seal bearing into rotational contact with the lower plate of the holder.

[0034] In another aspect of the invention, the rotor assembly can further include a retainer having a first cylindrical sleeve with an inner surface, and a first annular flange extending radially inward from a bottom of the first cylindrical sleeve and defining a second central opening, the first annular flange providing a frictional or slip fit with the liquid transport assembly. The first cylindrical sleeve can have an inner diameter sufficient to define an annular space between the inner surface of the first cylindrical sleeve and the liquid transport assembly, and the first end of the second resilient member is retained within the annular space.

[0035] In another aspect of the present invention, the rotor assembly can further include a bearing support including a second cylindrical sleeve and a second annular flange extending radially inward from an upper portion of the second cylindrical sleeve. The second annular flange can include an upper surface, a lower surface, and define a third central opening that provides a snug fit with the liquid transport assembly. The bearing support can be configured such that the second end of the second resilient member engages with the lower surface of the second annular flange, and the upper surface of the second annular flange engages with the bottom surface of the seal bearing.

[0036] In another aspect of the invention, the second cylindrical sleeve may have an inner diameter that is larger than the outer diameter of the first cylindrical sleeve, providing a snug fit between the first and second cylindrical sleeves.

[0037] In another aspect of the invention, the rotor assembly can further include a third elastic member, the second annular flange can include a second inner groove, and the third elastic member can be disposed within the second inner groove and can couple the bearing support to the liquid transport assembly.

[0038] In another embodiment of the present invention, the first and third elastic members may be O-rings, and the second elastic member may be a coil spring.

[0039] In another embodiment of the present invention, a method for centrifuging a liquid medium containing a first component and a second component is provided. The method includes providing a first volume of the liquid medium to a rotor, accelerating the rotor in one or more steps until the rotor reaches a first angular velocity that causes at least a portion of the liquid medium to separate into the first and second components, and decelerating the rotor in one or more steps until the rotor reaches a second angular velocity that is less than the first angular velocity. While the rotor is rotating at the second angular velocity, the method includes removing at least a portion of the first component from the rotor, and adding a second volume of the liquid medium to the rotor after removing the first component from the rotor. The method then accelerates the rotor in one or more steps until the rotor reaches a first angular velocity that causes at least a portion of the second volume of the liquid medium to separate into the first and second components, such that the second component accumulates within the rotor.

[0040] In another aspect of the invention, accelerating the rotor in one or more stages until the rotor reaches a first angular velocity may include accelerating the rotor at a first angular acceleration until the rotor reaches a third angular velocity; rotating the rotor at the third angular velocity for a first period of time; and accelerating the rotor at a second angular acceleration greater than the first angular acceleration after the first period of time expires until the rotor reaches the first angular velocity.

[0041] In another aspect of the invention, while the rotor is rotating at a third angular velocity, the third angular velocity may cause the surface of the liquid medium to have a parabolic shape, and while the rotor is rotating at the first angular velocity, the first angular velocity may cause the surface of the liquid to have a cylindrical shape.

[0042] In another aspect of the invention, the third angular velocity can be approximately 100 revolutions per minute and the first angular velocity can be between 5,000 and 5,500 revolutions per minute.

[0043] In another aspect of the invention, decelerating the rotor in one or more stages until the rotor reaches the second angular velocity may include decelerating the rotor at a third angular acceleration until the rotor reaches a fourth angular velocity; rotating the rotor at the fourth angular velocity for a second period of time; and decelerating the rotor at a fourth angular acceleration less than the third angular acceleration after the second period of time expires until the rotor reaches the second angular velocity.

[0044] In another embodiment of the invention, yet another method for centrifuging a liquid medium containing a first component and a second component is provided, the method including adding a first batch of liquid medium to a rotor containing a bioprocess bag having a plurality of internal pockets, accelerating the rotor in one or more steps until the rotor reaches a first angular velocity that separates at least a portion of the liquid medium into the first component and the second component, and accumulating the second component in the plurality of internal pockets.

[0045] In one aspect of the invention, the method may further include decelerating the rotor in one or more stages until the rotor reaches a second angular velocity less than the first angular velocity, and removing a portion of the first component from the rotor while the rotor is rotating at the second angular velocity. After removing the portion of the first component from the rotor, the method may add a second batch of liquid medium to the rotor, accelerate the rotor in one or more stages until the rotor reaches the first angular velocity, and accumulate the second component of the second batch of liquid medium in the plurality of internal pockets.

[0046] In another aspect of the invention, the method may further include repeating the steps of decelerating the rotor to a second angular velocity, removing a portion of the first component from the rotor, adding another batch of liquid medium to the rotor, accelerating the rotor to the first angular velocity, and accumulating the second component in the plurality of internal pockets, and removing the second component from the rotor.

[0047] In another aspect of the invention, removing the second component from the rotor may include stopping rotation of the rotor and removing the bioprocess bag from the rotor. [Brief explanation of the drawings]

[0048] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate certain embodiments of the invention and, together with the general description of the invention given above and the detailed description given below, serve to explain the invention. [Figure 1] 1 is a perspective view of a continuous flow sealed rotor assembly according to one embodiment of the present invention; [Figure 2] 2 is a partially exploded perspective view of the rotor assembly of FIG. 1 showing the cover, rotor, base, and containment shell of the rotor assembly. [Figure 3] FIG. 3 is an exploded perspective view of the rotor of FIG. 2. [Figure 4] FIG. 2 is a schematic cross-sectional view of the rotor assembly of FIG. 1. [Figure 5] 4 is another schematic cross-sectional view of the rotor assembly of FIG. 1, showing additional details not clearly visible in FIG. [Figure 6] FIG. 6 is an enlarged view of a portion of the rotor assembly of FIG. 5 showing additional details thereof. [Figure 7] FIG. 6 is an enlarged view of another portion of the rotor assembly of FIG. 5, showing additional details thereof. [Figure 8] FIG. 10 is a perspective view of a continuous flow sealed rotor assembly according to another embodiment of the present invention. [Figure 9]9 is a partially exploded perspective view of the rotor assembly of FIG. 8 showing the cover, rotor, base, and containment shell of the rotor assembly. [Figure 10] FIG. 9 is a schematic cross-sectional view of the rotor assembly of FIG. 8. [Figure 11] FIG. 11 is an enlarged view of a portion of the rotor assembly of FIG. 10 showing additional details thereof. [Figure 12] FIG. 11 is an enlarged view of another portion of the rotor assembly of FIG. 10 showing additional details thereof. [Figure 13] FIG. 11 is an enlarged view of yet another portion of the rotor assembly of FIG. 10 showing additional details thereof. [Figure 14] 11 is a schematic cross-sectional view of a liquid transport assembly of the rotor of FIG. 10. [Figure 15] FIG. 9 is a perspective view of a subassembly of the rotor assembly of FIG. 8, including a fluid transfer assembly, a bioprocess bag, and a holder. [Figure 16] FIG. 16 is an exploded perspective view of the subassembly of FIG. 15. [Figure 17] FIG. 16 is a schematic cross-sectional view of the subassembly of FIG. 15. [Figure 18] FIG. 10 is a perspective view of a continuous flow sealed rotor assembly according to yet another embodiment of the present invention. [Figure 19] 19 is a partially exploded perspective view of the rotor assembly of FIG. 18 showing the cover, rotor, base, and containment shell of the rotor assembly. [Figure 20] FIG. 19 is a schematic cross-sectional view of the rotor assembly of FIG. 18. [Figure 21] FIG. 21 is an enlarged view of a portion of the rotor assembly of FIG. 20 showing additional details thereof. [Figure 22] FIG. 19 is a schematic cross-sectional view of the rotor assembly of FIG. 18 including a lower seal assembly. [Figure 23] FIG. 23 is an enlarged view of a portion of the rotor assembly of FIG. 22 showing additional details thereof. [Figure 24] FIG. 24 is a schematic diagram of a process that can be used with the rotor assembly of FIGS. 1-23 for centrifugation of liquid culture media according to one embodiment of the present invention. [Figure 25] FIG. 24 is a schematic diagram of a process that can be used with the rotor assembly of FIGS. 1-23 for centrifugation of liquid culture media according to one embodiment of the present invention. [Figure 26] FIG. 24 is a schematic diagram of a process that can be used with the rotor assembly of FIGS. 1-23 for centrifugation of liquid culture media according to one embodiment of the present invention. [Figure 27] FIG. 24 is a schematic diagram of a process that can be used with the rotor assembly of FIGS. 1-23 for centrifugation of liquid culture media according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0049] Embodiments of the present invention are directed to a rotor for continuous processing of biological suspensions using processing vessels in the form of a sealed rotor assembly that allows for a "plug and play" centrifugation system that minimizes the effort required by the user of the rotor assembly.

[0050] 1-7 illustrate a continuous-flow sealed rotor assembly 10 according to one embodiment of the present invention. The rotor assembly 10 includes a housing 11, which includes a cover 12 and a base 14, a rotor 16, and a containment shell 18. The base 14 may include a circumferential rim 15 having an outer surface with a rabbet 17. The cover 12 may have an opening 19 that is slightly larger in diameter than the circumferential rim 15. The diameter of the opening 19 may allow the cover 12 to be coupled to the base 14 by a resilient member 20 (e.g., a gasket) that provides a friction fit between the inner surface of the cover 12 and the rabbet 17 of the base 14. The cover 12 and the base 14 may thereby be operably coupled to one another, such that the housing 11 provides a sealed chamber 22 for containing the rotor 16.

[0051] 6 , a flange 21 defined by rabbet 17 can provide a stop for a lower edge 23 of cover 12 to ensure that cover 12 is axially positioned relative to base 14. Cover 12 can include one or more handles 24 and a reinforcing plate 26 having multiple (e.g., two) threaded bores 28, 30. Threaded bores 28, 30 can be configured to receive a supply assembly 32 and a decant assembly 34, respectively. Reinforcing plate 26, supply assembly 32, and decant assembly 34 can include a liquid transport assembly 35 for supplying and decanting liquid medium to and from rotor assembly 10.

[0052] The base 14 may be coupled to the containment shell 18 by one or more fasteners 36, such as, for example, nuts and bolts. The base 14 and containment shell 18 may each include respective central holes 38, 40 that may couple the rotor 16 to the centrifuge. The central holes 38, 40 allow the rotor 16 to rotate within the sealed chamber 22 while the housing 11 and containment shell 18 remain stationary. The containment shell 18 may be configured to collect any material that leaks from the sealed chamber 22.

[0053] As best shown in Figures 3-5, the rotor 16 may include a torque transfer module 42, a drive hub 44, a drum 46, a bioprocess bag 48, a pressure ring 50, a retaining ring 52, a holder 54, a compression ring 55, and a stiffener 56. The torque transfer module 42 may function as both a pressure plate and a torque transfer member. The torque transfer module 42 may include a top surface having a central bore 58, a keyed recess 60 centered about the central bore 58, and a plurality of protrusions 62 configured to engage corresponding recesses 64 in the drum 46, as shown in Figure 5.

[0054] The drive hub 44 may include a bore 66 configured to receive a centrifuge spindle and a keyed flange 68 configured to engage the keyed recess 60 of the torque transfer module 42. A threaded portion of the drive hub 44 may be configured to receive a retaining nut 70. The retaining nut 70 may be configured to threadingly engage the threaded portion of the drive hub 44. In response to tightening the retaining nut 70, a portion of the torque transfer module 42 providing the lower surface of the keyed recess 60 may be compressed between the keyed flange 68 of the drive hub 44 and an upper surface of the retaining nut 70. The rotor 16 may thereby be securely coupled to the drive hub 44 by the retaining nut 70.

[0055] The drum 46 may include a generally circular base 72 having an upper surface 80, a lower surface 71, an outer rim 73, and a circumferential wall 74 having an inner surface 75 and an outer surface 77 (see FIGS. 3-5). The circumferential wall 74 may project generally upward from the outer rim 73 to define an opening 76 (FIG. 3), which may be angled inward such that the opening 76 in the drum 46 has a smaller diameter than the base 72 of the drum 46. A plurality of axially aligned baffles 78 may project radially inward from the inner surface 75 of the circumferential wall 74. Each baffle 78 of the drum 46 is hollow and includes an opening at its base to provide a recess 64 that engages with a respective protrusion 62 of the torque transfer module 42, as described above and shown in FIG. 5.

[0056] The upper surface (or inner surface) 80 of the base 72 may have a shallow, upwardly facing bowl shape that defines a collection area 81 proximate the axis of rotation 82 of the rotor assembly 10, as shown in Figures 4 and 5. To this end, the upper surface 80 may have a radial slope that is nearly zero (i.e., nearly flat in the horizontal plane) proximate the center of the base 72 of the drum 46. The radial slope increases with increasing radial distance from the center of the base 72, such that gravity pushes the liquid medium contained in the drum 46 toward the center of the base 72 when the rotor assembly 10 is stationary.

[0057] The feed assembly 32 may include an input port in the form of a feed valve 84 (e.g., a ball valve) coupled to an inlet of a feed fitting 86 by an external feed tube 88. The feed assembly 32 may include an outlet port in the form of a nozzle 90 coupled to an outlet of the feed fitting 86 by an internal feed tube 92. The internal feed tube 92 may be configured to orient the nozzle 90 to dispense liquid medium in a generally outward direction from the axis of rotation 82.

[0058] The decant assembly 34 may include an output port in the form of a decant valve 94 (e.g., a ball valve) coupled to the outlet of the decant fitting 96 by an external decant tube 98, and an input port 100 fluidly coupled to the inlet of the decant fitting 96 by an internal decant tube 102. The internal decant tube 102 may be configured so that the input port 100 of the decant assembly 34 is optimally positioned for removing liquid medium (e.g., supernatant) during the centrifugation process. For example, the internal decant tube 102 may be configured to position the input port 100 of the decant assembly 34 in close proximity to the collection area 81 of the drum 46. Advantageously, the collection area 81 allows the decant assembly 34 to decant a greater proportion of the liquid medium from the rotor 16 than would be possible with a rotor lacking this feature, by allowing the input port 100 to be positioned lower within the rotor 16 and by concentrating the liquid medium around the input port 100.

[0059] As shown in Figures 3-5, the bioprocess bag 48 may include a lower portion 104 and an upper portion 108. The lower portion 104 of the bioprocess bag 48 may include a plurality of internal pockets 106. The upper portion 108 of the bioprocess bag 48 may include an axially aligned neck 110 and a radially aligned skirt 112 extending outward from the top of the neck 110. The neck 110 of the bioprocess bag 48 may define an opening through which liquid medium can be added to the bioprocess bag 48 and processed components of the liquid medium can be removed from the bioprocess bag 48. The external pockets 114 between adjacent internal pockets 106 of the bioprocess bag 48 may be configured to engage with the baffles 78 of the drum 46. This engagement can prevent the bioprocess bag 48 from moving or rotating relative to the drum 46 when the rotor 16 is subjected to angular acceleration by the centrifuge.

[0060] 7 , the pressure ring 50 may include a radially aligned flange 116 defining an opening 118 and a circumferential wall 120 extending generally downwardly from the outer edge of the flange 116. The opening 118 may be configured to receive the axially aligned neck 110 of the bioprocess bag 48. A circumferential ridge 122, centered about the axis of rotation 82 of the rotor assembly 10, may project upwardly from the upper surface of the flange 116. The circumferential ridge 122 may include an axially aligned, inwardly facing surface 124 configured to center the retaining ring 52 about the opening 118 of the pressure ring 50.

[0061] The retaining ring 52 may include a circumferential channel 130 on its underside and a plurality of threaded holes 132 each configured to threadably engage a retaining bolt 133. The holder 54 may include an axially aligned circumferential wall 134 and a radially aligned flange 136. The circumferential wall 134 may include an inwardly facing surface 138 that defines an opening 139 in the rotor 16 and an outwardly facing surface 140 that engages the neck 110 of the bioprocess bag 48. The flange 136 is joined to an upper portion of the circumferential wall 134 and extends radially outward therefrom and may include a plurality of through holes 135 configured to pass the retaining bolts 127 therethrough.

[0062] The compression ring 55 can include an upper surface 141, a lower surface 143, and a plurality of through holes 126 configured to pass through the retaining bolts 133. The upper surface 141 of the compression ring 55 can include a vertically recessed annulus 142 that is open to the axial side of the compression ring 55. The vertically recessed annulus 142 can cooperate with the lower surface 144 of the flange 136 of the holder 54 to provide a radially aligned circumferential channel that receives at least an outer portion of the skirt 112 of the bioprocess bag 48.

[0063] The retaining ring 52 and holder 54 may be configured to cooperate with the pressure ring 50 and compression ring 55 to secure the bioprocess bag 48 within the rotor 16. The compression ring 55 may be subjected to a compressive force between the upper surface 145 of the retaining ring 52 and the lower surface 144 of the flange 136 when the retaining bolts 133 are tightened while threadedly engaged with the threaded holes 132 of the retaining ring 52. This compressive force may secure the skirt 112 of the bioprocess bag 48 between the vertically recessed annulus 142 of the compression ring 55 and the lower surface 144 of the flange 136. The outward facing surface 140 of the circumferential wall 134 presses the neck 110 of the bioprocess bag 48 against the pressure ring 50, ensuring that the skirt 112 of the bioprocess bag 48 is inserted completely and flat within the circumferential channel defined between the compression ring 55 and the flange 136 of the holder 54.

[0064] The stiffener 56 may include one or more spiral windings extending around the circumferential walls 74, 120 of the drum 46 and pressure ring 50. The stiffener 56 may be formed by a filament winding process followed by a compression molding process using a suitable material, such as epoxy-coated carbon fiber. For example, the stiffener 56 may be compression molded onto the rotor 16 after placing a layer of resin-coated carbon fiber laminate material or wrapping one or more strands of carbon fiber around the outward surface of the circumferential wall 74. The stiffener 56 may be configured to withstand a majority of the centrifugal forces applied to the rotor 16. Methods for forming stiffeners for centrifuge rotors using a filament winding process are described in detail in U.S. Patent No. 8,323,169, issued December 4, 2012, the disclosure of which is incorporated herein by reference in its entirety.

[0065] 8-17 illustrate a continuous flow sealed rotor assembly 150 according to another embodiment of the present invention, where like reference numerals refer to like components of rotor assembly 10. Rotor assembly 150 includes a housing 151 including base 14 and cover 152, a rotor 154, and a containment shell 156.

[0066] As best shown in FIGS. 8-10 , the cover 152 may include a cap 158 and a barrel 160. The barrel 160 may include an upper edge 161, a lower edge 162, and one or more flanges 163, e.g., three flanges. Each flange 163 may include a threaded bore 165 and may extend radially inward from the upper edge 161 of the barrel 160. As best shown in FIG. 11 , a circumferential rabbet 164 may be disposed on the inward-facing surface of the barrel 160 proximate the lower edge 162 of the barrel 160. The circumferential rabbet 164 may include a circumferential groove 166 in its radially aligned surface. The circumferential groove 166 may be configured to receive the circumferential rim 15 of the base 14. The flange 21 of the base 14 may provide a stop for the lower edge 162 of the barrel 160.

[0067] When barrel 160 is operably coupled to base 14, circumferential rabbet 164 and circumferential groove 166 may cooperate to position barrel 160 both axially and radially relative to base 14. Advantageously, embodiments of the present invention having a configuration of circumferential rabbet 164 and circumferential groove 166 may avoid using a resilient member (e.g., resilient member 20) to couple cover 152 to base 14.

[0068] 12 and 13 , the cap 158 may include a central bore 168 having a diameter d1 and a periphery 170 having a groove 172 configured to receive a resilient member 174, such as an O-ring. The central bore 168 may be configured to receive a bushing 176 that positions the liquid transport assembly 178 relative to the cap 158, for example, by centering the liquid transport assembly 178 in the central bore 168. To this end, the bushing 176 may have an outer diameter d2 approximately the same size as the diameter d1 of the central bore 168, an inner diameter d3 configured to provide a friction fit with the liquid transport assembly 178, and upper and lower flanges 179 a, 179 b that extend radially beyond the outer diameter d2 and axially position the bushing 176 relative to the cap 158. The cap 158 may be operably coupled to the barrel 160 by fasteners 180 (e.g., bolts) that threadingly engage threaded bores 165 in the flange 163 of the barrel 160. The resilient member 174 may provide a fluid-tight seal such that the base 14, cap 158, and barrel 160, when assembled, form a housing 151 that provides the sealed chamber 22 in which the rotor 154 rotates.

[0069] 10 , 16 , and 17 , rotor 154 may include a holder 182 having a lower section 184 and an upper section 186. When operably coupled together, lower section 184 and upper section 186 of holder 182 may define a central cavity 188 configured to contain a bearing assembly 190 and an annular cavity 192 surrounding central cavity 188.

[0070] The lower section 184 of the holder 182 may include an axially aligned circumferential wall 196, a radially aligned flange 194 extending radially outward from an upper portion of the circumferential wall 196, and a lower plate 198 coupled to a lower portion of the circumferential wall 196. The lower plate 198 may include a central opening 200 through which the liquid transport assembly 178 may be inserted. A lower portion of the central cavity 188 may be defined by a cylindrical annulus 202 projecting upwardly from the lower plate 198. The flange 194 may include one or more (e.g., four) holes 203 configured to receive shafts of the retaining bolts 133 therethrough. The retaining bolts 133 may operably couple the lower section 184 to the retaining ring 52 by engaging with the threaded holes 132 thereof.

[0071] The upper section 186 of the holder 182 may include a circumferential wall 204 and a top plate 206. The top plate 206 may be coupled to an upper portion of the circumferential wall 204. The diameter of the circumferential wall 204 may be such that the circumferential wall 204 of the upper section 186 fits within the circumferential wall 196 of the lower section 184. The top plate 206 may include a central opening 208 through which the liquid transport assembly 178 may be inserted. A cylindrical ring 210 may project downwardly from the top plate 206 to define an upper portion of the central cavity 188.

[0072] The holder 182 can be configured such that, when assembled, the central opening 208 of the upper plate 206 is axially aligned with the central opening 200 of the lower plate. This alignment can allow the liquid transport assembly 178 to be inserted through the holder 182, thereby allowing a lower portion of the liquid transport assembly 178 to protrude into the bioprocess bag 48 when the holder 182 is placed in the rotor assembly 150. The cylindrical rings 202 and 210 of the lower plate 198 and upper plate 206 can also be axially aligned to define the central cavity 188. The upper section 186 of the holder 182 may be held in place relative to the lower section 184 of the holder 182 by pressure applied to the upper section 186 by the underside of the bushing 176, by a friction fit with the liquid transport assembly 178, or by any other suitable means.

[0073] The bearing assembly 190 may be configured to facilitate rotation of the rotor 154 about the liquid transport assembly 178 during operation of the centrifuge. To this end, as best shown in FIG. 13 , the bearing assembly 190 may include an upper bearing 212 and a lower bearing 214 separated axially by a cylindrical spacer 216. Each bearing 212, 214 may include an inner ring 218 that provides a bore 220 and an outer ring 222 that positions the bearings 212, 214 within the central cavity 188. The bore 220 of each bearing 212, 214 may be configured to allow the liquid transport assembly 178 to pass through the bearing assembly 190.

[0074] The inner ring 218 and the outer ring 222 may each have an upper surface and a lower surface. The outer ring 222 of the bearings 212, 214 may be sized and shaped to contact the vertical surfaces of the central cavity 188, thereby holding the bearing assembly 190 in place radially. The cylindrical spacer 216 may have a length such that the upper surface of the upper bearing 212 and the lower surface of the lower bearing 214 engage with the respective horizontal surfaces of the central cavity 188. This allows the bearing assembly 190 to be held in place axially by the upper and lower horizontal surfaces of the central cavity 188.

[0075] Each bearing 212, 214 may be configured to allow the inner ring 218 and outer ring 222 to rotate relative to one another. To this end, the inner ring 218 may have an inner race 228, and the outer ring 222 may have an outer race 230 that cooperates to house respective bearing members 232, e.g., balls, rollers, etc. The bearing members 232 housed by the inner race 228 and outer race 230 may be maintained in a substantially fixed position relative to one another by one or more of a cage and a guide ring (not shown).

[0076] 10 and 14, the liquid transport assembly 178 can include a decant assembly 234 and a feed assembly 236. The decant assembly 234 can include a decant tube 238 having an input port 240 (e.g., an opening) at its lower end and an output port 242 (e.g., a barbed nozzle) at its upper end. The decant tube 238 can extend into the bioprocess bag 48 a sufficient distance to position the input port 240 optimally for removing liquid medium (e.g., supernatant) during centrifugation, for example, so that the input port 240 is proximate to the collection area 81 of the drum 46.

[0077] The feed assembly 236 may include a feed tube 244 operably coupled to an input port 246. The input port 246 of the feed assembly 236 may include a fitting 248 (e.g., a barbed nozzle) coupled to the interior of the feed tube 244 via a lateral opening 250. The lateral opening 250 may be proximate an upper end 252 of the feed tube 244. The fitting 248 may be configured to receive a flexible tube through which a liquid medium (e.g., a biological suspension) is provided to the rotor assembly 150. One or more (e.g., three) lateral openings 254 proximate a lower end 256 of the feed tube 244 may provide output ports 258 through which the liquid medium can be provided to the bioprocess bag 48. The output ports 258 of the feed assembly 236 may be configured such that the liquid medium is distributed radially outward into the bioprocess bag 48.

[0078] A section of supply tube 244 located between (e.g., approximately midway between) upper end 252 and lower end 256 of supply tube 244 may include an integral collar 259 having a larger outer diameter than the upper and lower portions of supply tube 244. The integral collar 259 of supply tube 244 may provide a friction fit between supply tube 244 and the inner surface of bushing 176. The integral collar 259 may facilitate passage of the lower portion of liquid transport assembly 178 through bushing 176 by allowing this section of supply tube 244 to have an outer diameter smaller than the inner diameter of bushing 176.

[0079] Decanting tube 238 may pass longitudinally through supply tube 244 and have an outer diameter d5 that is smaller along at least a portion thereof than an inner diameter d6 of supply tube 244. Decanting tube 238 and supply tube 244 may thereby define an annular channel 260 between an outer surface of decanting tube 238 and an inner surface of supply tube 244. Annular channel 260 may fluidly couple input port 246 of supply assembly 236 to output port 258 of supply assembly 236.

[0080] The inner diameter of the supply tube 244 may be reduced near its upper end 252 and lower end 256. This reduced inner diameter may cause the inner surface of the supply tube 244 to contact the outer surface of the decant tube 238 near the upper and lower ends of the supply tube 244. The contact between the inner surface of the decant tube 238 and the outer surface of the supply tube 244 may seal the upper and lower ends of the annular channel 260 such that suspension flowing into the input port 246 of the supply assembly 236 is directed through the annular channel 260 and distributed into the bioprocess bag 48 through the output port 258 of the supply assembly 236. In another embodiment, the upper and lower ends of the annular channel 260 may be sealed by one or more of a sleeve, an O-ring, an increase in the outer diameter of the decant tube 238, or any other suitable method. Thus, embodiments of the present invention are not limited to liquid transport assemblies 178 in which the upper and lower ends of the annular channel 260 are sealed by sections of the decant tube 238 having a reduced inner diameter.

[0081] 18-21 illustrate a continuous flow sealed rotor assembly 270 according to another alternative embodiment of the present invention, with like reference numerals referring to like components of rotor assemblies 10, 150 described above. Rotor assembly 270 includes a liquid transport assembly 272 having an integral collar 274 and an upper seal assembly 276. Integral collar 274 may include an outer surface having a threaded portion 275 and a smooth portion 277. Seal assembly 276 may include a torque retaining hub 278, a seal drive hub 280, and an upper seal bearing 282.

[0082] Torque-retaining hub 278 may be configured to be received by central bore 168 of cap 158 made from a semi-rigid material (e.g., hard rubber) and may include a central bore 279 configured to receive seal drive hub 280. Central bore 279 of torque-retaining hub 278 may have a non-circular shape, such as an oval, a polygonal shape (e.g., a hexagonal shape), or another suitable shape that resists rotation.

[0083] Seal drive hub 280 may include a threaded bore 284, an outer surface 286, and an underside 288 including one or more protrusions 290. Threaded bore 284 of seal drive hub 280 may be configured to threadingly engage threaded portion 275 of integral collar 274. Outer surface 286 of seal drive hub 280 may have a non-circular cross-sectional shape (e.g., hexagonal) configured to engage a central bore of torque-retaining hub 278. The non-circular shape of outer surface 286 of seal drive hub 280 may prevent seal drive hub 280 from rotating relative to torque-retaining hub 278.

[0084] The seal bearing 282 may include a circumferential ring 296 including an upper surface 292 with one or more notches 294 configured to receive the protrusions 290. Each protrusion 290 of the seal drive hub 280 may engage a respective notch 294 of the seal bearing 282, thereby preventing the seal bearing 282 from rotating relative to the seal drive hub 280. The circumferential ring 296 of the seal bearing 282 may further include an inner groove 298 in which a resilient member 300 (e.g., a silicone O-ring) is positioned, and a smooth lower surface 302. The seal bearing 282 may remain in a fixed angular position about the rotation axis 82 and may press down on the upper section 186 of the holder 182 as the rotor 154 rotates. The pressure provided by the seal assembly 276 may keep the drive hub 44 of the rotor assembly seated in the centrifuge spindle during centrifugation.

[0085] The seal drive hub 280 may be configured to conduct heat generated by friction between the lower surface 302 of the seal bearing 282 and the upper section 186 of the holder 182 away from the seal bearing 282. To increase the thermal conductivity of the seal drive hub 280, the seal drive hub 280 may include an embedded heat pipe. Additional features that may be included in embodiments of the present invention to control heat within the seal bearing 282 include adjusting the amount of torque on the seal drive hub 280 or using high-temperature materials within the seal bearing 282.

[0086] Advantageously, the seals provided by the seal assembly 276 both inside and outside the rotor 154 can prevent feed material ejection due to rotation of the rotor 154. The seal assembly 276 may be part of a disposable rotor assembly, in which case the seal bearings 282 need only have an operational life sufficient to process enough suspension to fill the bioprocess bag 48 to pellet capacity, e.g., about 6 hours of operation. To reduce cost, the seal assembly 276 can comprise molded plastic, e.g., an injection molded plastic part that provides a "snap-on" design.

[0087] Advantageously, and with particular reference to Figure 20, the liquid transport assembly 272 remains stationary while the rotor 154 rotates. The liquid transport assembly 272 provides an internal passageway through which the supernatant can exit the rotor 154, and a circular passageway around the internal passageway through which the incoming liquid (such as a suspension of cells in the supernatant) can enter the rotor 154.

[0088] 22 and 23 illustrate a continuous-flow sealed rotor assembly 310 according to another alternative embodiment of the present invention, where like reference numerals refer to like components of rotor assemblies 10, 150, 270 described above, and where rotor assembly 310 includes a lower seal assembly 312. Lower seal assembly 312 can operate alone or in conjunction with upper seal assembly 276 to prevent feed material ejection due to rotation of rotor 154. Lower seal assembly 312 can include a lower seal bearing 314 and a support assembly 316. Support assembly 316 can bias seal bearing 314 axially upward along liquid transport assembly 272 to provide positive engagement between seal bearing 314 and lower section 184 of holder 182.

[0089] The seal bearing 314 may include a circumferential ring 318 that includes a smooth upper surface 320, an inner groove 322 in which a resilient member 324 (e.g., a silicone O-ring) is positioned, and a smooth lower surface 326. The seal bearing 314 may remain in a fixed angular position about the rotational axis 82 and may push the lower plate 198 of the holder 182 upward as the rotor 154 rotates.

[0090] The upper seal bearing 282 and the lower seal bearing 314 may be made from a material that produces wear products that are non-cytotoxic, Class VI, etc., to facilitate removal of wear products from the centrifuged liquid media components in downstream processes. The seal bearings 282, 314 may be made from high-performance plastics (e.g., polyimide (PI), polyamideimide (PAI), polybenzimidazole (PBI), etc.) or internally lubricated acetal-based materials such as Turcite®, available from Aetna Plastics Corp. of Cleveland, Ohio.

[0091] The support assembly 316 may include a retainer 328 and a bearing support 330. The retainer 328 may include a cylindrical sleeve 332 and an annular flange 334 extending radially inward from the bottom of the cylindrical sleeve 332. The annular flange 334 may define a central opening 336 through which the liquid transport assembly 178 can be inserted. The central opening 336 may have a diameter slightly larger than the outer diameter of the supply tube 244. The central opening 336 of the retainer 328 may thereby provide a friction or slip fit with the supply tube 244 of the liquid transport assembly 272. The diameter of the central opening 336 may be sufficiently close to the outer diameter of the supply tube 244 to prevent lateral movement of the retainer 328. The retainer 328 may be positioned along the supply tube 244 by a retaining ring 338 that engages a groove 340 in the outer surface of the supply tube 244.

[0092] The cylindrical sleeve 332 of the retainer 328 can have an inner diameter sufficiently larger than the outer diameter of the supply tube 244 to define an annular space 342 between the inner surface of the cylindrical sleeve 332 and the outer surface of the supply tube 244. The central opening 336 can be configured to concentrically align the cylindrical sleeve 332 with the supply tube 244 so that the annular space 342 is evenly distributed around the outer surface of the supply tube 244. The annular space 342 can be configured to receive a resilient member 344, such as a coil spring. The retainer 328 can position the resilient member 344 relative to the supply tube 244 such that the resilient member 344 biases the seal bearing 314 upward when compressed.

[0093] The bearing support 330 may include a cylindrical sleeve 346 and an annular flange 348 extending radially inward from the top of the cylindrical sleeve 346. The annular flange 348 may include an inner groove 350 in which a resilient member 352 (e.g., a silicone O-ring) is positioned, defining a central opening 354 through which the liquid transport assembly 272 can be inserted. The central opening 354 may have a diameter slightly larger than the outer diameter of the supply tube 244. The central opening 354 of the bearing support 330 may provide a snug fit with the supply tube 244 of the liquid transport assembly 178, thereby allowing axial movement of the bearing support 330. The diameter of the central opening 354 may be sufficiently close to the outer diameter of the supply tube 244 to prevent significant lateral movement of the bearing support 330. The central opening 354 may thereby contribute to maintaining axial alignment between the bearing support 330 and the retainer 328.

[0094] The cylindrical sleeve 346 of the bearing support 330 may have an inner diameter sufficiently larger than the outer diameter of the cylindrical sleeve 332 of the retainer 328 to provide a snug fit between the cylindrical sleeves 332, 346 that allows axial movement of the bearing support 330. The cylindrical sleeves 332, 346 may thereby contribute to maintaining axial alignment between the retainer 328 and the bearing support 330 while allowing axial movement of the bearing support 330. To ensure free movement of the bearing support 330, the position of the retaining ring 338 along the supply tube 244 may be selected to provide a headspace 356 between the top of the sleeve 332 of the retainer 328 and the bottom surface of the flange 348.

[0095] The centrifuge in which rotor 154 rotates can be equipped to pump or otherwise convey suspension from a bioreactor or the like through an annular passage to rotor 154. The centrifuge may also be equipped to convey supernatant from rotor 154 through an internal passage. Incoming and outgoing liquids can enter and exit rotor 154 at suitable flow rates and for suitable periods of time, examples of which are described below in connection with Figures 24 and 25.

[0096] A centrifuge for use in embodiments of the present invention may include a spindle, a housing defining a chamber configured to receive a rotor assembly, a drive unit, a lid configured to allow the rotor assembly to be loaded into and removed from the chamber, and a controller. The housing and chamber may each be made from any suitable material. For example, the housing may be made from galvanized and powder-coated high-strength steel, and the chamber may be made from stainless steel.

[0097] The drive unit may include a motor (e.g., an induction motor) and a drive circuit that provides power to the motor in response to signals from the controller. The motor may include an output shaft operably coupled to the spindle and one or more input terminals operably coupled to the drive circuit. The controller may provide signals to the drive circuit that cause the motor to selectively apply torque to the spindle. The controller may thereby control the angular acceleration and speed of the rotor according to a centrifugation process programmed into the controller.

[0098] The lid can be configured to secure the rotor assembly to the centrifuge. To this end, the lid can include a locking mechanism that prevents the lid from being opened while the rotor is spinning and an opening configured to accommodate the liquid transport assembly. One or both of the lid and the housing can include a sensor that detects whether the lid is closed and latched. A controller can be operably coupled to the sensor and the locking mechanism and configured to prevent the centrifuge lid from being opened unless the centrifuge is switched on and the rotor has completely stopped. The controller can also prevent the centrifuge from starting until the lid is properly closed. The locking mechanism can include a mechanical release that allows the locking function to be overridden so that the lid can be opened in an emergency. For example, the mechanical release can open the lid to allow the rotor assembly to be removed in the event of a power outage.

[0099] The controller may include a processor, memory, and input / output (I / O) interfaces. The processor may include one or more devices that perform operations on data based on internal logic or operational instructions stored in the memory. The memory may include a single memory device or multiple memory devices that can store data. Computer program code embodied as one or more computer software applications resident in the memory may have instructions that are executed by the processor. One or more data structures may also reside in the memory and be used by the processor or applications to store or manipulate data.

[0100] The I / O interface may provide a mechanical interface that operatively couples the processor to other devices and systems, such as sensors, drive units, and user interfaces. Thus, by communicating via the I / O interface, applications may cooperate with external devices and systems to provide various functions, features, applications, processes, or modules of embodiments of the present invention.

[0101] The user interface can be configured to allow a user to select or otherwise program operational parameters into the centrifuge, such as run speed, relative centrifugal force (RCF), run time, run temperature, and run profile (acceleration and braking curves). To this end, the user interface can include one or more of a keypad, keypad lock, option indicators, a display, menu keys, function keys, or other suitable devices for receiving input from and providing information to the user. For example, the display can include one or more of an alphanumeric or dot matrix display, a touch screen, light-emitting diodes, etc., to display information about the operating status of the centrifuge. The user interface can provide several preset acceleration and braking curves (e.g., nine acceleration curves and ten deceleration curves) that the user can select. The user interface can also be configured to allow a user to save centrifugation programs for future use and select previously saved centrifugation programs for execution by the controller.

[0102] The acceleration and braking curves may include slow start, slow stop, and brake-off curves. The slow start curve may provide gradual acceleration in the low speed range (e.g., 0-250 RPM) and transition to normal or maximum angular acceleration at speeds above the low speed range (e.g., 250 RPM to maximum RPM, which may range from 6,000-10,000 RPM). The slow start acceleration rate provided by the centrifuge during the centrifugation process may be defined by the selected acceleration curve. For example, the acceleration profiles may be numbered (e.g., from 1 to 9) such that the lowest number provides the lowest slow start acceleration rate, and each successive number provides an increasingly higher slow start acceleration rate up to the highest number.

[0103] Similarly, the slow-stop curve may provide gentle deceleration over another low-speed range (e.g., 0-500 RPM) and provide nominal deceleration braking from the operating speed to the upper limit of the low range. That is, for a reduced speed range of 0-500 RPM and an operating speed of 6,000 RPM, the slow-stop curve may transition from the nominal deceleration rate to a lower slow-stop deceleration rate as the rotor of the rotor assembly slows down to 500 RPM. The slow-stop deceleration rate may be defined by selecting one of a number of numbered deceleration profiles (e.g., 1 to 10), with the lowest number providing the slowest slow-stop deceleration rate.

[0104] The brake-off curve selection may disable the nominal deceleration brake for coast-to-stop from any specified speed. In this case, the time it takes for the rotor of the rotor assembly to stop depends on the specified transition speed, windage, friction, and rotor inertia. The brake-off transition speed can be set independent of the running speed and may be unaffected by changes in running speed. If the transition speed is set faster than the running speed, the centrifuge may coast to a stop from the running speed at the end of the run, at the end of the centrifugation step or process.

[0105] The centrifuge controller may be operably coupled to a liquid handling system including one or more pumps, valves, manifolds, and tubing. The liquid handling system may be configured to selectively define a flow path that couples the input port of the supply assembly to a source of liquid medium (e.g., suspension) to be processed and the output port of the decant assembly to a container that receives the processed liquid medium, e.g., supernatant or pellet. Enabling the centrifuge controller to control when liquid medium is added to and removed from the bioprocess bag 48 may facilitate automation of continuous flow and batch processing of liquid medium. In particular, the centrifuge controller may add liquid medium to and remove processed liquid medium from the rotor assembly at specific points in the centrifugation process, e.g., at specific rotor speeds or during specific processing steps.

[0106] 24-27 depict exemplary centrifugation processes 410, 430 for separating components of a liquid medium in accordance with embodiments of the present invention. For clarity, reference will be made to FIGS. 20 and 22 in the following description, although it should be understood that embodiments of the present invention are not limited to the specific flow paths illustrated by these figures. Thus, it should be further understood that other suitable flow paths may also be used, such as the flow paths provided by other exemplary liquid transport assemblies 35, 178 described herein, and other similar flow paths.

[0107] 24 and 25, in step 1 of process 410, the rotor 154 may be empty and stationary. While the rotor assembly 270, 310 is in this initial state, the process 410 can proceed to step 2, where an initial volume (e.g., 25 liters) of suspension 412 can be loaded into the bioprocess bag 48, for example, through one of the internal or annular paths of the liquid transport assembly 272. The suspension 412 can be loaded, for example, by gravity feed or by pumping the suspension 412 from a bioreactor or other suspension source into the input port 246 of the feed assembly 236. While stationary, the air-liquid interface 414 between the suspension 412 and the air within the sealed chamber can be essentially flat.

[0108] After the initial amount of suspension 412 is loaded into the bioprocess bag 48, the process 410 can proceed to step 3 and begin accelerating the rotor 154 to a transfer rotation speed, e.g., 100-150 revolutions per minute (RPM). To avoid excessive agitation of the suspension 412 due to movement of the bioprocess bag 48 relative to the suspension 412, the rate of angular acceleration during this initial spin-up phase is relatively low (e.g., 0.15 rad / s). 2 )could be.

[0109] In response to the angular velocity of the suspension 412 increasing to the transfer rotation speed, the gas-liquid interface 414 of the suspension 412 may begin to acquire a parabolic shape. This parabolic shape may result from the suspension 412 responding to centrifugal forces generated by the rotation of the suspension 412 relative to a fixed reference frame. The centrifugal forces may also cause the gas-liquid interface 414 proximate the axis of rotation to move downward along the bottom of the liquid transport assembly 272 as the rotation speed increases. This increase in the depth of the parabolic shape may cause the input port 240 of the decant assembly 234 to become partially or completely uncovered by the suspension 412 as the rotation speed increases.

[0110] After a period of time (e.g., 3-5 minutes) at the transfer rotation speed, the process 410 can proceed to step 4, where the rotor 154 can be accelerated to an operational rotation speed (e.g., 5,000-5,500 RPM). The movement of the suspension 412 into the interior pocket 106 of the bioprocess bag 48 due to increased centrifugal force is driven by a relatively high angular acceleration (e.g., 6.0 rad / s) during this spin-up phase of operation. 2 The operating rotational speed may be acceptable. The operating rotational speed may generate sufficient centrifugal force to cause the gas-liquid interface 414 of the suspension 412 to become cylindrical, which in turn may cause the suspended solids to separate from the suspension liquid and settle into the interior pocket 106 of the bioprocess bag 48.

[0111] Once the rotor 154 reaches the operating rotational speed, the process 410 proceeds to step 5, where the operating rotational speed can be maintained for a centrifugation period, e.g., 30 minutes. During this phase, solids in the suspension 412 that have a higher density than the suspended solids tend to sink (e.g., move radially outward), while solids lighter than the suspended solids tend to float (e.g., move radially inward). By replacing or supplementing gravity with a much stronger centrifugal force, the operating rotational speed can dramatically increase the rate at which solids are separated from the suspended solids. Thus, centrifugation allows for the separation of components of a liquid medium that only differ slightly in density, while suspensions with a greater density difference between the solids and the liquid will separate at a faster rate. As the suspended solids collect in the internal pockets 106 of the bioprocess bag 48, pellets 416 may form in each internal pocket 106 below a layer of supernatant 418. The pellets 416 may be separated from the supernatant 418 by a pellet-supernatant interface 420 with a neo-angle that depends on the rotational speed.

[0112] The liquid medium can be largely contained within the internal pocket 106 of the bioprocess bag 48 while the centrifuged liquid medium is subjected to sufficient centrifugal force to cause centrifugation such that the gas-liquid interface of the liquid medium assumes a cylindrical or frusto-conical shape. The containment can allow for higher rates of angular acceleration and deceleration without causing excessive turbulence to, and therefore mixing of, the various components of the separated liquid medium (e.g., pellet 416 and supernatant 418) compared to the rotational speed at which the gas-liquid interface 414 would assume a parabolic shape or otherwise exit the internal pocket 106 of the bioprocess bag 48.

[0113] After rotor 154 has rotated at the operating rotational speed for the centrifugation period, process 410 may proceed to step 6 and begin a multi-stage deceleration of rotor 154. Process 410 may first decelerate rotor 154 from the operating rotational speed to the transition rotational speed (e.g., 800 RPM) at a moderate angular deceleration rate, e.g., 1.5 rad / s. 2 The transition rotation speed may be the rotation speed at which the supernatant 418 begins to emerge from the interior pocket 106 of the bioprocess bag 48.

[0114] Once the rotor 154 has been decelerated to the transition rotational speed, the process 410 determines whether the deceleration rate is slower than the initial deceleration stage, e.g., 0.15 rad / sec. 2 During this deceleration phase, the process 410 can slow the rotational speed from the transition speed to a transfer rotational speed, for example, 100 RPM. While the rotor 154 is rotating at the transfer rotational speed, the centrifugal force may be low enough for the gas-liquid interface 414 to resume its parabolic shape. The resulting fluid distribution may submerge the input port 240 of the decant assembly 234 in the supernatant 418 while maintaining the pellets 416 in the lower corners of the interior pocket 106 of the bioprocess bag 48.

[0115] While the rotor 154 is rotating at the transfer speed, the process 410 can activate the evacuation pump or otherwise decant the supernatant 418 through the decant assembly from the bioprocess bag 48. Once the supernatant 418 has been decanted from the bioprocess bag 48, the process 410 can proceed to step 7.

[0116] In step 7, the supernatant 418 is largely removed from the bioprocess bag 48, and the pellet 416 may remain in the lower corner of the internal pocket 106. At this point, the process 410 can refill the bioprocess bag 48 with fresh suspension and return to step 3. The process 410 can thereby repeat the separation step and continue to accumulate pellet material in the internal pocket of the bioprocess bag 48. After a sufficient amount of pellet material has been collected (e.g., the internal pocket 106 of the bioprocess bag 48 has reached or near capacity), the process 410 can slow the rotor 154 to zero RPM so that the pellet 416 can be removed. For example, if the incoming suspension contains 5 to 10 percent cells or other pellet-forming components, one can expect to perform five or more cycles of introducing the suspension, centrifugation, and decanting the supernatant before the internal pocket 106 of the bioprocess bag 48 is filled to or near capacity for the pellet 416 at the end of the last centrifugation round. In any event, once the pellets 416 are removed, the bioprocess bag 48 can be replaced with a new bioprocess bag 48 so that the rotor assemblies 270, 310 can be reused.

[0117] For certain types of pellet material, it may also be feasible to wash the pellet 416 with a buffer solution at the end of the final round of centrifugation. The buffer solution may be introduced via the supply assembly 236 (e.g., via the annular path) and removed via the decant assembly 234 (e.g., via the internal path). Once the pellet 416 has been washed away, one or more rounds of fresh suspension are introduced and centrifuged, possibly followed by one or more rounds of supernatant decantation.

[0118] Advantageously, the process 410 may allow large volumes of suspension to be processed automatically by allowing the supernatant to be emptied from the bioprocess bag 48 and replaced with fresh suspension without removing the rotor 154 from the rotor assembly 270, 310 or the rotor assembly 270, 310 from the centrifuge. This may be particularly advantageous when processing suspensions with a relatively low percentage of solids, so that large volumes of suspension can be processed before the bioprocess bag 48 contains a sufficient amount of pellets 416 to require replacement.

[0119] 26 and 27, in step 1 of process 430, the rotor 154 may be empty and stationary. While the rotor assembly 270, 310 is in this initial state, the process 430 proceeds to step 2, where an initial volume (e.g., 20 liters) of density gradient solution 432 can be loaded into the bioprocess bag 48, for example, through the interior or one of the circular paths of the liquid transport assembly 272. This initial volume may be less than the total capacity of the rotor 154, allowing for the addition of another solution at a later stage. The density gradient solution 432 may be loaded, for example, by gravity feed or by pumping the density gradient solution 432 into the input port 246 of the feed assembly 236. While stationary, the air-liquid interface 434 between the density gradient solution 432 and the air within the sealed chamber may be essentially flat.

[0120] After the initial amount of density gradient solution 432 is loaded into the bioprocess bag 48, the process 430 can proceed to step 3 and begin accelerating the rotor 154 to a transfer rotation speed, e.g., 100-150 revolutions per minute (RPM). To avoid excessive agitation of the density gradient solution 432 due to movement of the bioprocess bag 48 relative to the density gradient solution 432, the rate of angular acceleration during this initial spin-up phase is relatively low (e.g., 0.15 rad / s). 2 ) can be done.

[0121] In response to the angular velocity of the density gradient solution 432 increasing to the transfer rotation speed, the gas-liquid interface 434 of the density gradient solution 432 can begin to acquire a parabolic shape. This parabolic shape may result from the density gradient solution 432 responding to centrifugal forces generated by the rotation of the density gradient solution 432 relative to a fixed reference frame. The centrifugal forces may also cause the gas-liquid interface 434 proximate the axis of rotation to move downward along the bottom of the liquid transport assembly 272 as the rotation speed increases. This increase in the depth of the parabolic shape may cause the input port 240 of the decant assembly 234 to become partially or completely uncovered by the density gradient solution 432 as the rotation speed increases.

[0122] After a period of time (e.g., 3-5 minutes) at the transfer rotation speed, the process 430 can proceed to step 4, where the rotor 154 can be accelerated to the operating rotation speed (e.g., 5,000-5,500 RPM). The movement of the density gradient solution 432 into the interior pocket 106 of the bioprocess bag 48 due to the increased centrifugal force is achieved by a relatively high angular acceleration (e.g., 6.0 rad / s) during this spin-up phase of operation. 2 ) may be acceptable. The operating rotation speed can generate enough centrifugal force to cause the air-liquid interface 434 of the density gradient solution 432 to assume a cylindrical shape. Once the rotor 154 reaches the operating rotation speed, the process 430 allows the density gradient solution 432 to stabilize for 2 to 3 minutes to form a density gradient along the radial direction.

[0123] After the density gradient solution forms a density gradient, process 430 may proceed to step 5, where a volume of suspension 436 (e.g., 5 liters) may be added to rotor 154 to bring the total volume of fluid up to the capacity of rotor 154 (e.g., 25 liters). In response to suspension 436 being added to rotor 154, a band-like gradient may begin to form at the interface between suspension 436 and density gradient solution 432.

[0124] The process 430 can proceed to step 6, where the operating rotational speed can be maintained for a centrifugation period, e.g., 60 minutes. During this phase, banded fluid particles can begin to settle toward the maximum radius of the rotor 154. Over time, these particles can create cylindrical isopycnic layers 438-441 arranged according to relative density. This can occur as solids within the density gradient solution 432 seek their level; denser solids tend to sink to the lower layers of the density gradient solution 432 (e.g., by migrating radially outward), while less dense solids tend to remain in the lower layers. By replacing or supplementing gravity with a much stronger centrifugal force, the operating rotational speed can dramatically increase the rate at which solids are separated into isopycnic layers 438-441.

[0125] After the rotor 154 has rotated at the operating rotational speed for the centrifugation period, the process 430 may proceed to step 7 and begin slowly decelerating the rotor 154 to zero rpm. In response to the reduction in centrifugal force, the isopycnic layers 438-441 may form horizontal layers stacked on top of each other based on their relative densities. Once the rotor 153 has stopped, the process 430 may discharge the isopycnic layers 438-441 in separate stages.

[0126] In step 8, the isopycnic layers 438-441 can be largely removed from the bioprocess bag 48. At this point, the process 430 can refill the bioprocess bag 48 with new density gradient solution 432 and return to step 3. The process 430 can thereby repeat the separation steps and continue processing the suspension 436. In an alternative embodiment, the bioprocess bag 48 can be replaced with a new bioprocess bag 48 and the rotor assembly 270, 310 can be reused, for example, to process a different suspension.

[0127] While the present invention has been illustrated by descriptions of specific embodiments thereof, and the embodiments have been described in considerable detail, it is not intended that the appended claims be limited to, or in any way restricted to, such details. The various features discussed herein can be used alone or in any combination. Additional advantages and modifications will be readily apparent to those skilled in the art. Therefore, the present invention in its broadest aspects is not limited to the specific details, representative apparatus and methods, and illustrative examples shown and described. Accordingly, departures may be made from such details without departing from the scope or spirit of the general inventive concept.

Claims

1. 1. A rotor assembly for centrifuging a liquid medium, comprising: a bioprocess bag including a lower portion and an upper portion, the upper portion of the bioprocess bag including an axially aligned neck connected to the lower portion of the bioprocess bag and a radially aligned skirt extending outward from the axially aligned neck; a drum including a first base having an outer rim and a first circumferential wall extending upwardly from the outer rim, the first circumferential wall including a first outer surface and a first inner surface, the first inner surface defining a first opening for receiving the lower portion of the bioprocess bag; a pressure ring including a first radially aligned flange and a second circumferential wall, the first radially aligned flange including a first upper surface, an outer edge, and an inner edge defining a second opening, the second circumferential wall having a second inner surface extending downwardly from the outer edge and engaging the first outer surface of the first circumferential wall of the drum; a holder including a third circumferential wall having an outwardly facing surface and a second radially aligned flange having a first lower surface, the second radially aligned flange extending outwardly from a top of the third circumferential wall, and at least one of the outwardly facing surface and the first lower surface operably coupling the top of the bioprocess bag to the pressure ring.

2. 10. The rotor assembly of claim 1, further comprising a compression ring including a second upper surface having a recessed annulus open on an axial side of the compression ring and defining a radially aligned circumferential channel with the first lower surface of the second radially aligned flange of the holder, the radially aligned circumferential channel configured to receive at least a portion of the radially aligned skirt of the bioprocess bag.

3. the second radially aligned flange of the holder and the compression ring each include a plurality of through holes; a plurality of retaining bolts; a retaining ring including a plurality of threaded holes, each configured to receive a respective one of the retaining bolts, each retaining bolt passing through a respective through hole in the second radially aligned flange and the compression ring; The rotor assembly of claim 2 , wherein said compression ring is subjected to a compressive force by said radially aligned second flange and said retaining ring in response to tightening of said retaining bolts.

4. 4. The rotor assembly of claim 3, wherein the pressure ring includes a circumferential ridge projecting upwardly from the first upper surface of the first radially-aligned flange and includes an axially-aligned inwardly facing surface configured to center the retaining ring about the second opening defined by the inner edge of the pressure ring.

5. A rotor assembly according to claim 1 , wherein the drum includes a plurality of axially aligned baffles.

6. 6. The rotor assembly of claim 5, wherein the lower portion of the bioprocess bag includes a plurality of internal pockets and a plurality of external pockets each disposed between two adjacent internal pockets, each external pocket configured to engage with a respective one of the axially aligned baffles of the drum.

7. each of the axially-aligned baffles includes a hollow, and the first base includes a second lower surface having a third opening into the hollow of each axially-aligned baffle; 7. The rotor assembly of claim 5, further comprising a torque transferring module including a third upper surface having a plurality of protrusions each configured to engage a respective third opening in the second lower surface of the first base.

8. a housing including a cover and a second base configured to receive the cover; 8. The rotor assembly of claim 1, wherein the bioprocess bag, the drum, the pressure ring, and the holder comprise a rotor that rotates within the housing.

9. the third circumferential wall of the holder includes an inwardly facing surface that defines a fourth opening; a decant assembly having an input port that passes through the cover and the fourth opening and through which first liquid medium is removed from the bioprocess bag; the first base includes a fourth upper surface having an upwardly facing bowl shape that defines a water collection area proximate an axis of rotation of the rotor; The rotor assembly of claim 8 , wherein the input port of the decant assembly is located adjacent to the water collection area.

10. 10. The rotor assembly of claim 9, further comprising a feed assembly including a feed assembly output port that passes through the cover and the fourth opening and through which a second liquid medium is provided to the bioprocess bag.

11. The rotor assembly of claim 10 , wherein the first liquid medium is a supernatant and the second liquid medium is a suspension.

12. the supply assembly further includes a supply assembly input port and a supply tube having a third inner surface with a first diameter; the decant assembly includes a decant tube having a second outer surface with a second diameter smaller than the first diameter, the decant tube passing longitudinally through the supply tube; the first diameter is greater than the second diameter along at least a portion of the decant tube such that the decant tube and the supply tube define an annular channel between the second outer surface of the decant tube and the third inner surface of the supply tube; The rotor assembly of claim 10 or 11, wherein the annular channel fluidly couples the feed assembly input port to the feed assembly output port.

13. a bearing assembly; 13. The rotor assembly of any one of claims 8 to 12, further comprising a liquid transport assembly that passes through the cover and the bearing assembly and includes a first port through which a first liquid medium is removed from the bioprocess bag and a second port through which a second liquid medium is provided to the bioprocess bag.

14. The holder is a lower section including a first cylindrical ring; an upper section including a second cylindrical ring; The rotor assembly of claim 13 , wherein the first cylindrical ring and the second cylindrical ring define a central cavity that retains the bearing assembly when the lower section is coupled to the upper section.

15. The bearing assembly an upper bearing including a first inner ring having a first bore; a lower bearing including a second inner ring having a second bore; a cylindrical spacer that positions the upper bearing perpendicular to the lower bearing; A rotor assembly according to claim 13 or 14, wherein the first bore and the second bore couple the bearing assembly to the liquid transport assembly.

16. 16. The rotor assembly of claim 13, further comprising a sealed bearing having a fifth upper surface and a third lower surface, the sealed bearing coupled to the cover of the housing via the fifth upper surface and in rolling contact with the holder via the third lower surface.

17. 17. The rotor assembly of claim 16, further comprising: a seal drive hub including a third outer surface and a fourth lower surface, said seal drive hub coupled to said cover of said housing via said third outer surface and coupled to said fifth upper surface by said fourth lower surface.

18. the fourth lower surface includes one or more protrusions; the fifth top surface includes one or more notches; The rotor assembly of claim 17 , wherein each of the projections engages a respective notch, thereby preventing the seal bearing from rotating relative to the seal drive hub.

19. the seal drive hub 19. The rotor assembly of claim 17 or 18, further comprising one or more heat pipes configured to conduct heat away from the sealed bearing.

20. the cover of the housing includes a first central hole; The rotor assembly of claim 17 , further comprising a torque retaining hub coupling the seal drive hub to the first central bore.

21. the torque-retaining hub includes a second central bore having a non-circular shape; 21. The rotor assembly of claim 20, wherein the third outer surface of the seal drive hub has the non-circular shape and is configured to engage the second central bore of the torque-carrying hub, such that the non-circular shape prevents the seal drive hub from rotating relative to the torque-carrying hub.

22. the seal drive hub includes a threaded bore; the liquid transport assembly including an integral collar having a fourth outer surface with a threaded portion configured for threaded engagement with the threaded bore of the seal drive hub; 22. A rotor assembly according to any one of claims 17 to 21, wherein the liquid transport assembly is coupled to the cover of the housing by the seal drive hub.

23. the liquid transport assembly includes an integral collar having a fourth outer surface with a smooth portion, and the seal bearing includes an internal groove; 23. A rotor assembly as described in any one of claims 16 to 22, further comprising a resilient member disposed in the inner groove of the seal bearing that provides a fluid-tight seal between the seal bearing and the smooth portion of the fourth outer surface of the integral collar of the liquid transport assembly.

24. the holder includes a first central opening; a fluid transfer assembly that passes through the first central opening and includes a first port through which a first liquid medium is removed from the bioprocess bag and a second port through which a second liquid medium is provided to the bioprocess bag; a sealed bearing including a first internal groove and a second upper surface in rolling contact with the holder; 24. The rotor assembly of claim 1, further comprising: a first resilient member disposed in the first inner groove of the seal bearing coupling the seal bearing to the liquid transport assembly.

25. 25. The rotor assembly of claim 24, wherein the holder includes a lower plate coupled to a lower portion of the third circumferential wall, the first central opening being in the lower plate.

26. 26. The rotor assembly of claim 25, further comprising a second resilient member having a first end and a second end, the second resilient member configured to bias the seal bearing into the rolling contact with the lower plate of the holder.

27. a retainer including a first cylindrical sleeve having an inner surface and a first annular flange extending radially inward from a bottom of the first cylindrical sleeve; the first annular flange defining a second central opening that provides a friction or slip fit with the liquid transport assembly; a first cylindrical sleeve having an inner diameter sufficient to define an annular space between the inner surface of the first cylindrical sleeve and the liquid transport assembly; 27. The rotor assembly of claim 26, wherein the first end of the second resilient member is retained within the annular space.

28. a bearing support including a second cylindrical sleeve and a second annular flange extending radially inward from a top of the second cylindrical sleeve; the second annular flange having an upper surface, a lower surface, and defining a third central opening that provides a snug fit with the liquid transport assembly; 28. The rotor assembly of claim 27, wherein the second end of the second resilient member engages the lower surface of the second annular flange and the upper surface of the second annular flange engages the bottom surface of the seal bearing.

29. 29. The rotor assembly of claim 28, wherein the second cylindrical sleeve has an inner diameter that is larger than an outer diameter of the first cylindrical sleeve, providing a snug fit between the first and second cylindrical sleeves.

30. Further comprising a third elastic member; the second annular flange includes a second internal groove; 30. A rotor assembly according to claim 28 or 29, wherein the third resilient member is disposed in the second inner groove and couples the bearing support to the liquid transport assembly.

31. 31. The rotor assembly of claim 30, wherein the first and third resilient members are O-rings and the second resilient member is a coil spring.

32. 1. A method for centrifuging a liquid medium comprising a first component and a second component, comprising: providing a first amount of the liquid medium to a rotor; accelerating the rotor in one or more steps until the rotor reaches a first angular velocity that causes at least a portion of the liquid medium to separate into the first component and the second component; decelerating the rotor in one or more steps until the rotor reaches a second angular velocity that is less than the first angular velocity; While the rotor is rotating at the second angular velocity, removing at least a portion of the first component from the rotor; adding a second amount of the liquid medium to the rotor after removing the portion of the first component from the rotor; and accelerating the rotor in one or more steps until the rotor reaches the first angular velocity that causes at least a portion of the second amount of the liquid medium to separate into the first component and the second component such that the second component accumulates within the rotor.

33. accelerating the rotor in one or more steps until the rotor reaches the first angular velocity; accelerating the rotor at a first angular acceleration until the rotor reaches a third angular velocity; rotating the rotor at the third angular velocity for a first period of time; 33. The method of claim 32, comprising: after the first period of time expires, accelerating the rotor at a second angular acceleration greater than the first angular acceleration until the rotor reaches the first angular velocity.

34. 34. The method of claim 33, wherein while the rotor is rotating at the third angular velocity, the third angular velocity causes a surface of the liquid medium to have a parabolic shape, and while the rotor is rotating at the first angular velocity, the first angular velocity causes the surface of the liquid medium to have a cylindrical shape.

35. 35. The method of claim 33 or 34, wherein the third angular velocity is about 100 revolutions per minute and the first angular velocity is between 5,000 and 5,500 revolutions per minute.

36. decelerating the rotor in one or more steps until the rotor reaches the second angular velocity comprises: decelerating the rotor at a third angular acceleration until the rotor reaches a fourth angular velocity; rotating the rotor at the fourth angular velocity for a second period of time; and after the second period of time expires, decelerating the rotor at a fourth angular acceleration less than the third angular acceleration until the rotor reaches the second angular velocity.

37. 1. A method for centrifuging a liquid medium comprising a first component and a second component, comprising: adding a first batch of liquid medium to a rotor containing a bioprocess bag having a plurality of internal pockets; accelerating the rotor in one or more steps until the rotor reaches a first angular velocity that causes at least a portion of the liquid medium to separate into the first component and the second component; and storing the second component in the plurality of internal pockets; decelerating the rotor in one or more steps until the rotor reaches a second angular velocity that is less than the first angular velocity; removing the portion of the first component from the rotor while the rotor is rotating at the second angular velocity, and adding a second batch of the liquid medium to the rotor after removing the portion of the first component from the rotor; accelerating the rotor in one or more steps after the second batch of liquid medium is added to the rotor until the rotor reaches the first angular velocity; and accumulating the second component of the second batch of liquid medium in the plurality of internal pockets.

38. repeating the steps of decelerating the rotor to the second angular velocity, removing the portion of the first component from the rotor, adding another batch of the liquid medium to the rotor, accelerating the rotor to the first angular velocity, and accumulating the second component in the plurality of internal pockets; 38. The method of claim 37, further comprising removing the second component from the rotor.

39. 39. The method of claim 38, wherein removing the second component from the rotor includes stopping rotation of the rotor and removing the bioprocess bag from the rotor.

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