Hollow Shaft Impeller

Abstract

The hollow shaft impeller has a hollow impeller housing, a magnet, an impeller cap, an impeller retainer, and a plurality of impeller blades. The impeller housing has a hub defining an interior volume and an impeller bore providing access to the interior volume. The magnet may be dimensioned to be disposed within the interior volume. The impeller cap may be removably coupled to the hollow impeller housing proximate the impeller bore. The impeller retainer may be removably coupled to the magnet and dimensioned to be disposed within the interior volume. The plurality of impeller blades may protrude from the hub. Optionally, a fin may be disposed on each of the plurality of impeller blades.

Description

[Technical Field]

[0001] This application claims priority to U.S. Provisional Patent Application No. 63 / 292,445, filed December 22, 2021, entitled "HOLLOW SHAFT IMPELLER," the disclosure of which is incorporated herein by reference in its entirety for all purposes.

[0002] This application relates to bioprocessing containers such as storage tanks, bioreactors, and other vessels. In particular, embodiments of the technology disclosed herein relate to mixers useful in bioprocessing containers. [Background technology]

[0003] Biofluids containing cells and other viral vectors are produced in bioreactors and other vessels in the pharmaceutical and biopharmaceutical industries. Previous bioreactors were rigid stainless steel or glass vessels with highly controlled processing parameters, including pH, oxygen and carbon dioxide concentrations, turbidity, and temperature, which were monitored and controlled by permanent sensors built into the rigid bioreactor. During bioprocessing, such as cell growth within a biofluid in a bioreactor, uniform distribution of temperature, gases, and nutrients was maintained by mixing. A suitable mixing system serves three functions: creating a stable environment with homogeneous distribution (nutrients, pH, temperature, etc.), dispersing gases (i.e., supplying O2 and extracting CO2), and optimizing heat transfer. Many components, such as buffers, adjuvants, oxygen, cell culture media, etc., are mixed into the biofluid. Providing acceptable mixing without damaging shear effects becomes more challenging as the size of bioreactor containers increases. The inclusion of a well-designed impeller allows for better mixing efficiency without the risk of high shear associated with high impeller speeds.

[0004] The mixing system typically includes an impeller with a shaft and blades protruding from the shaft, which is connected to a motor located outside the bioreactor. Multi-use stainless steel reactors require intensive cleaning and sterilization before reuse. Impellers, spargers, and sensors (e.g., gas, temperature, and pH sensors) are also multi-use components and require sterilization after each batch process. More recent developments in bioprocessing have led to the emergence of disposable bioreactors, which offer greater flexibility in manufacturing and may reduce the time required for effective regeneration or sterilization of equipment. Processors have begun utilizing disposable sterile containers, such as bags that are used once and discarded, typically with a shaft connected to a top-mounted motor. Disposable bioreactors use disposable bags constructed from thin, flexible polymer films. Sterile disposable bags containing components (e.g., disposable sensors and impellers) eliminate the need for cleaning, sterilization, and validation. Therefore, their use results in significant savings in manufacturing and maintenance costs. A bioprocessing challenge associated with disposable bags and components is the positioning of the components within the flexible bioreactor after sterilization. After sterilization, the flexible bioreactor is stored and shipped. Unlike rigid stainless steel vessels, bioreactor bags do not have structural rigidity and are prone to wear and tear.

[0005] Typically, bioreactor components such as impeller shafts, spargers, and sensors have been attached to the interior of rigid vessels by threaded posts, bolts, clamps, and / or other joining methods with seals and bearings. These methods were not suitable for flexible bioreactor bags because they resulted in damage, leaks, contamination, and other failure modes of the flexible bioreactor bags both before and during processing.

[0006] Homogeneous mixing is important. However, thorough mixing can damage cells by introducing high amounts of shear. Many mixing operations are performed in bioreactors with mixing impellers mounted near the bottom of the vessel. A variety of impellers with different sizes and shapes of impeller hubs, impeller blades, and shafts were required to achieve mixing within the many different sizes and shapes of bioreactors. Past prior art bioprocessing techniques included stirred tanks and systems to complete the mixing process. Such systems achieved mixing by using mechanical agitators, which were lowered into the biological fluid through an opening in the top of the vessel and rotated by an external motor to create the desired mixing action. Such systems were also inefficient and required additional motors and components. Summary of the Invention [Problem to be solved by the invention]

[0007] Attempts to solve these problems consist of systems for mixing biological fluids using a rotating magnetic impeller magnetically coupled to a shaft and conductive elements. The magnetic impeller is installed within a container and positioned adjacent to the conductive elements. The container is sealed with the magnetic impeller within it, and the biological fluid is delivered after sealing. However, a remaining limitation of this approach is that magnetic interaction alone provides "support" for the magnetic impeller. These systems controlled the vertical levitation of the impeller but provided insufficient lateral control. Particularly at high speeds, the levitated impeller would wobble, resulting in damage to the disposable bioreactor. Second, external bearing rings were used to stabilize the magnetic impeller laterally, but they performed poorly, were heavy, and required a large amount of torque. Microprocessors utilizing feedback control are also required to stabilize the expensive bearing ring-type impellers. Some past impellers attempted to solve these processing problems by providing a flow path through the shaft, but these wobble and could not withstand turbulent flow. [Means for solving the problem]

[0008] Providing an improved mixing system for disposable containers or bioreactors for processing biological fluids, having a novel impeller that overcomes previous shortcomings to achieve the homogeneous mixing necessary for optimal cell culture growth, represents an advancement in the art. Significant improvements in efficiency, shorter mixing times, reduced power usage and increased power delivery, reduced shear and impeller oscillation, and ease of use are now realized, greatly expanding the potential applications for which advanced mixing systems can be used. Additionally, the novel and inventive embodiments described herein are useful for vessels, containers, and / or bioreactors capable of holding fluid volumes greater than 10 liters. In some embodiments, the fluid volume is between 10 L and 50 L. In some further embodiments, the fluid volume is between 40 L and 200 L. In some still further embodiments, the fluid volume is between 100 L and 500 L. In some additional embodiments, the fluid volume is between 200 L and 1000 L. In some embodiments, the fluid volume is between 400 L and 2000 L. It should be understood that a container or bioreactor capable of holding, for example, 50 L may process significantly less fluid, for example, 10 L.

[0009] An impeller is disclosed that can include an impeller cap, an optional gasket, an impeller retainer, and a circular magnet, all of which can be at least partially contained within a hollow impeller housing. The hollow impeller housing can include an impeller bore and a hub. The circular magnet can include a bore and be located within the impeller bore. The impeller cap can be fitted with an optional gasket or O-ring and can be at least partially disposed within the impeller bore along with the impeller retainer. The impeller can further include a plurality of impeller blades, which can protrude from the hub as shown in and / or described in connection with at least one of the figures. The novel and inventive features of the present disclosure, as well as details of exemplary embodiments thereof, will be more fully understood from the following description and drawings.

[0010] In at least one embodiment, the hollow shaft impeller includes a hollow impeller housing, a magnet, an impeller cap, an impeller retainer, and a plurality of impeller blades. The hollow impeller housing may have a hub defining an interior volume and an impeller bore providing access to the interior volume. The magnet may be dimensioned to be disposed within the interior volume. Additionally, the impeller cap may be removably coupled to the hollow impeller housing proximate the impeller bore. The impeller retainer may be removably coupled to the magnet and dimensioned to be disposed within the interior volume. The plurality of impeller blades may protrude from the hub of the hollow impeller housing.

[0011] In some cases, the plurality of impeller blades includes three, four, five, or more impeller blades. In certain further examples, at least one fin may be disposed on each impeller blade of the plurality of impeller blades, and the at least one fin may be triangular-shaped. In still further examples, the at least one fin may be disposed on each impeller blade of the plurality of impeller blades between a top edge and a bottom edge of each impeller blade of the plurality of impeller blades. The at least one fin may be disposed on and extend from a blade surface of each impeller blade of the plurality of impeller blades.

[0012] In still further examples, the hollow shaft impeller further includes a gasket coupled to the impeller cap. The gasket, together with the impeller cap, may be configured to seal the interior volume of the impeller bore. In additional examples, the gasket may be an O-ring. In even further examples, the gasket includes an elastomeric material, such as, but not limited to, a vinyl material, a polyethylene material, a polypropylene material, a nylon material, a silicone material, a polytetrafluoroethylene material, or a rubber material.

[0013] In certain other examples, the impeller retainer may include a circular flange having a top surface, an opposing bottom surface, a boss protruding from the top surface of the circular flange, and a cylinder descending from the bottom surface of the circular flange. The boss may be configured to interact with the impeller cap when the impeller retainer is disposed within the interior volume. The cylinder of the impeller retainer may include multiple rails disposed around the cylinder's outer surface. In certain further examples, the magnet may include a bore disposed at the center of the magnet and multiple slots disposed around the bore. The cylinder and multiple rails may be keyed to the bore and multiple slots of the magnet such that the bore and multiple slots of the magnet are configured to at least partially receive the cylinder and multiple rails of the impeller retainer. In certain additional examples, the magnet may be coupled to the impeller retainer when the cylinder and multiple rails of the impeller retainer are disposed within the bore and multiple slots of the magnet.

[0014] In yet further examples, the impeller cap may include a cap beam and a cap slot disposed about the impeller cap. Additionally, the impeller bore of the hollow shaft impeller may include a hub beam and a hub slot disposed about the impeller bore. The cap beam may be configured to be disposed in the hub slot, and the hub beam may be configured to be disposed in the cap slot when the impeller cap is coupled to the hollow impeller housing.

[0015] These advances and others embodied herein will become apparent from the following description, claims, and drawings. Various advantages, aspects, novel and inventive features of the present disclosure, as well as details of exemplary embodiments thereof, will become more fully understood from the following description and drawings. A detailed understanding of the features disclosed herein (i.e., a more specific description of the embodiments of the present disclosure briefly summarized above) can be obtained by reference to the accompanying drawings. It should be noted, however, that the accompanying drawings illustrate only exemplary embodiments of the present disclosure and should not be considered as limiting its scope. The described embodiments may tolerate other equally effective bags, biocontainers, films, and / or materials. It should also be understood that elements and features of one embodiment may be found in other embodiments without further recitation, and where possible, the same reference numerals have been used to indicate equivalent elements common to the figures. As used herein, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which these embodiments pertain.

[0016] In this disclosure, reference is made to an integral or unitary part. For purposes of this specification, a unitary or unitary part refers to a part that cannot be disassembled without destroying the part. For example, a hub with impeller arms that can be added or removed from the hub is not integral or unitary. Conversely, a hub with impeller arms that cannot be added or removed from the hub is unitary and / or integral. In some embodiments, an integral or unitary part is formed by a single manufacturing process, for example, injection molding of the hub and impeller arms in a single injection molding cycle.

[0017] The devices, systems, equipment, and components presented herein may be better understood by reference to the following drawings and description. It should be understood that some elements in the figures may not necessarily be to scale, emphasis instead being placed on illustrating the principles disclosed herein. In the figures, like reference numbers indicate corresponding parts / steps throughout the different views. [Brief explanation of the drawings]

[0018] [Figure 1] FIG. 1 is an exploded side perspective view of a hollow shaft impeller according to an embodiment of the present disclosure. [Figure 2] FIG. 2 illustrates a portion of a side view of a hub and impeller blades with fins according to an embodiment of the present disclosure. [Figure 3] FIG. 1 is a top perspective view of a cap for a hollow shaft impeller according to an embodiment of the present disclosure. [Figure 4] FIG. 1 is a top perspective view of a hollow shaft impeller according to an embodiment of the present disclosure. [Figure 5] FIG. 1 is a side perspective view of a bioprocessing system comprising a disposable bioreactor and a hollow shaft impeller having impeller blades further comprising fins, according to an embodiment of the present disclosure. [Figure 6] 10 is a graph illustrating impeller tilt parameters at tested rotational speeds, according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0019] Described herein are certain impeller embodiments that can be used in both systems directly connected to a rotary drive shaft and magnetically coupled levitating hollow shaft impellers that include magnets. Some impeller embodiments according to the present disclosure include a hollow shaft. Some impeller embodiments include a hollow shaft further comprising a cap disposed on the hollow shaft. Some impeller embodiments include a hollow shaft further comprising a three-pitch blade or four-pitch blade impeller. Some impeller embodiments include a hollow shaft further comprising a three-pitch blade or four-pitch blade impeller with one or more fins on one or more of the blades. The hollow shaft may be sealed by a cap that substantially prevents liquid ingress, and the cavity balances and / or stabilizes the impeller when immersed in liquid without the additional weight of a solid shaft or the attendant rocking of a flow-through shaft. Additionally, the additional weight requires additional torque, which adds cost and undesirably promotes rocking of the impeller. It is further believed that one or more hollow shafts better distribute torque. In the case of bottom-mounted impellers, the hollow shaft design reduces rocking and shortens mixing times. Furthermore, reduced rocking helps protect the bag containing the hollow shaft impeller during processing. Many embodiments of hollow shaft impellers are contemplated within the present disclosure. For example, blades of various sizes on the hollow shaft, blades of various shapes, fins of various sizes disposed on the blades or hollow shaft, and fins disposed on the blades in various positions are disclosed herein. For example, embodiments of the present disclosure include one or more fins on the shaft, one or more fins on the top of one or more blades, one or more fins on the bottom of one or more blades, and / or one or more fins in the center of one or more blades. Additional inventive features of some embodiments of one or more impellers include a cap with a pin and hole design and an internal cylinder within the hollow shaft for torque transmission, stability, and for holding, for example, a motor magnet in place.Hollow shaft embodiments disclosed herein are lighter, contain less material, have a higher polar moment of inertia, have a higher turning radius, and have higher torsional strength. Embodiments of the present disclosure also exhibit shorter mixing times, higher power inputs, and significantly reduced rocking for impellers used in 200 L-2000 L and larger sized bioreactors. Certain hollow shaft impeller embodiments, in which impeller blades have fins located within about 10% of the impeller blade's centerline width, exhibit little rocking or depression even at high revolutions per minute (RPM) (e.g., 100-120 RPM). Hollow shaft impellers with impeller blades further comprising fins located within 10% of the impeller blade's centerline width exhibit little rocking, even at high RPM, preventing the impeller blades and / or fins from hitting the bottom of the bioreactor bag or biocontainer, as described more fully below.

[0020] The term biocontainer is defined as any reactor, container, or vessel capable of holding a fluid within an internal volume or region, and may be in the form of a two-dimensional, three-dimensional, and / or multi-sided bag or bioreactor. In some embodiments, the biocontainer or bioreactor is flexible and has baffles built into it that can disrupt vortices within the liquid that form when a mixer, such as an impeller, mixes the liquid. Some embodiments also include spargers for delivering and distributing gas to the bioreactor. The bioreactor or container may also include a film. The term film, within the meaning of this disclosure, refers to any flexible material that can be fused with another flexible film, including, but not limited to, polymer sheets, composites, laminates, single-layer and / or multi-layer polymer materials. These films may further include substrates that may include plastic netting, woven fabrics, nonwoven fabrics, knits, and / or metal foils, as well as other flexible structures and materials. In some embodiments, the flexible film includes a laminated film structure with a low-melting-point material inside an outer high-melting-point polymer. Also, in some embodiments, the flexible film comprises a laminated film structure having a low melting point material surrounding a high melting point woven, knit, or nonwoven material. In some embodiments, any of the bottom, middle, or top films comprises any of the films as described in International Publication No. WO2020101848, the entire contents of which are incorporated by reference. In some embodiments, one or more of these films are substantially similar to the PUREFLEX®, PUREFLEXPLUS®, or ULTIMUS® films commercially available from EMD Millipore Corporation of Burlington, Massachusetts, USA.

[0021] FIG. 1 shows a side exploded perspective view of a hollow shaft impeller 100 according to an embodiment of the present disclosure. The hollow shaft impeller 100 includes an impeller cap 102 that optionally mates with a gasket 104. For example, the impeller cap 102 may include a groove 103 for receiving the gasket 104. In some embodiments, the gasket 104 is an O-ring. In some embodiments, the gasket 104 or O-ring is made of an elastomeric material, such as a vinyl material, a polyethylene material, a polypropylene material, a nylon material, a silicone material, a polytetrafluoroethylene material, a rubber material, and / or other polymeric materials known to those skilled in the art. The impeller retainer 106 includes a circular flange 110 having a top circular surface 110a and an opposite bottom circular surface 110b. As shown, a boss 107 protrudes from the top circular surface 110a. The impeller retainer 106 further includes a cylinder 116 that descends or protrudes from the bottom circular surface 110b. The cylinder 116 may include a plurality of rails 112 disposed around the outer surface of the cylinder 116. The circular flange 110 further includes a notch 114 that interacts with a knob on the inner portion of the hollow shaft impeller 100 (not shown in this view) and a centering member 118 formed on the periphery of the circular flange 110. The plurality of rails 112 of the cylinder 116 are configured to be keyed into a plurality of slots 122 formed around a centrally located bore 126 of the circular magnet 108. Thus, the bore 126 of the circular magnet 108 may be configured to at least partially receive the cylinder 116 of the impeller retainer 106, and the plurality of slots 122 are configured to at least partially receive the plurality of rails 112 of the cylinder 116. When the cylinder 116 and the plurality of rails 112 of the impeller retainer 106 are disposed within the bore 126 and the plurality of slots 122 of the magnet 108 , the magnet 108 is removably coupled to the impeller retainer 106 .

[0022] The hollow impeller housing 120 may further include a hub 130, which may define an interior volume 128, and an impeller bore that provides access to the interior volume 128. The impeller retainer 106 and the circular magnet 108 are sized and shaped to be disposed within the interior volume 128 such that the impeller retainer 106 and the circular magnet 108 are configured to be received within the hollow impeller housing 120. The impeller cap 102 may be removably coupled to the hollow impeller housing 120 at the impeller bore, and the gasket 104 may be configured to form a seal adjacent the impeller bore to seal the interior volume 128.

[0023] According to certain embodiments disclosed herein, and as previously described, the hollow impeller housing 120 may include a hub 130 including an upper end, a lower end, and at least first and second impeller arm slots 132 that are substantially vertically aligned and extend from the upper end toward the lower end. The impeller cap 102 may be disposed at the upper end of the hub 130 to seal a cavity therein. Also, at least first and second impeller blades 134 extend from the hub 130 in the arm slots 132. As shown in the embodiment illustrated in FIG. 1 , the hub 130 includes four arm slots 132 and four impeller blades 134. Each impeller blade 134 includes a blade face 136. Additionally, each impeller blade 134 may have an outer edge 138, an inner edge 142 opposite the outer edge 138, a bottom edge 145 extending between the outer edge 138 and the inner edge 142, and a top edge 147 opposite the bottom edge 145 and also extending between the outer edge 138 and the inner edge 142. The inner edge 142 of the impeller blade 134 may extend into the slot 132, into which the inner edge 142 may be engaged. In some embodiments, the inner edge 142 of the impeller blade 134 may engage with another impeller blade. As described in more detail below, each impeller blade 134 may further include a fin 140 disposed on and protruding / extending from the blade face 136.

[0024] As used herein, the impeller blades 134 and the hub 130 may be a single, integral part, i.e., a plastic part made by an injection molding process, and it is believed that the plastic part cannot be disassembled without destruction. The fins 140 may be subsequently attached to the impeller blades 134. For example, the fins 140 may be attached using screws, bolts, rivets, adhesives, cantilevers, snap fits, and / or other attachment means known to those skilled in the art. Alternatively, the impeller blades 134 and the fins 140 may be molded as a single, integral part and subsequently attached to the hub 130. As previously mentioned, the impeller blades 134 with the fins 140 molded as a single, integral part may be attached using screws, bolts, rivets, adhesives, cantilevers, snap fits, and / or other attachment means known to those skilled in the art. In certain embodiments, screws, bolts, rivets, adhesives, cantilevers, snap fits, and / or other attachment means known to those skilled in the art may be used to attach the impeller blades 134 to the hub 130 and the fins 140 to the impeller blades 134. Additionally, although the illustrated embodiment includes four blades 134, the hollow shaft impeller 100 may include any number of blades 134, including, but not limited to, three blades 134, four blades 134, five blades 134, etc.

[0025] In some embodiments, the fins 140 may each be substantially triangular, with the fins 140 having edges 140a, 140b, and 140c, with the edge 140a attached to the impeller blade 134. The edges 140a, 140b, and 140c may be linear or may form a curved or parabolic function. As shown, the edge 140b of the fin 140 begins a distance from the hub 130 and terminates at the outer edge 138 of the impeller blade 134. It is further contemplated that the fins 140 need not extend all the way to the outer edge 138. Furthermore, the fins 140 may extend close to or all the way to the surface of the hub 130. It is further contemplated that the fins 140 may form a right angle α with the impeller blade 134, or an angle α greater than or less than 90°. For example, in some embodiments, the angle α is approximately 50-80°. In one exemplary embodiment, the angle α is 76° relative to the axis of rotation clockwise toward the hub 130 when looking at the outer edge 138 of the impeller blade 134 .

[0026] FIG. 2 shows a partial side perspective view of a hub 130 and an impeller blade 134 having a fin 140 according to an embodiment of the present disclosure. The impeller blade 134 has a height BH, a length BL, and a centerline 162. Additionally, the fin 140 has a length FL and a height position FH along the height BH of the impeller blade 134. In one embodiment, the fin 140 is located approximately midway between the bottom edge 145 and the top edge 147 of the impeller blade 134. As shown, the fin 140 is located approximately 40% along the impeller blade height BH from the bottom edge 145. In other embodiments, the fin 140 may be located approximately 60% along the impeller blade height BH from the bottom edge 145. In one embodiment, the height FH of the fin 140 along the impeller blade 134 may be approximately 25% to 75% of the height BH of the impeller blade 134. The fins 140 may be positioned along the impeller blade height BH such that the fins 140 are positioned a distance 164 from the centerline 162 of the impeller blade 134. The outer diameter of the hub 130 may be approximately 2 centimeters (cm) to 15 centimeters. In certain embodiments, the outer diameter of the hub 130 may be approximately 10 to 11 cm. The length BL of the impeller blade 134 may be approximately 1 cm to 15 cm. In certain embodiments, the hollow shaft impeller 100 includes four impeller blades 134 arranged around the hub 130 such that the impeller blades 134 are equidistantly spaced from one another. In certain embodiments, the overall diameter of the hollow shaft impeller 100 is approximately 40 to 45 cm, the outer diameter of the hub 130 is approximately 10 to 30 cm, and each diametrically opposed impeller blade 134 is approximately 12 cm long. In an exemplary embodiment, the outer diameter of the hub 130 is 12 cm.

[0027] The impeller blade 134 has a thickness T. Generally, the thickness T is scalable for different impellers; for example, the thickness T may be approximately 0.20 to 0.5 cm. The fin 140 has a thickness T that is generally smaller than the thickness T of the impeller blade 134, for example, 0.15 to 0.4 cm. In some embodiments, the fin 140 has a length FL that is 50% of the length BL of the impeller blade 134. In other embodiments, the length FL may be 90% of the length BL of the impeller blade 134. As shown in FIG. 2, the length FL is approximately 90% of the length BL. It should be understood that the length FL, if shorter than the length BL, can begin at a point proximal to the hub 130 or distal to the hub 130. In one exemplary embodiment, the length BL may be approximately 60% to 80% of the length BL of the impeller blade 134. The impeller blades 134 may be oriented on the hub 130 such that the impeller blades 134 are at an angle θ from the bottom edge 149 of the hub 130. In an exemplary embodiment, the angle θ may be between 60 and 80 degrees. In an exemplary embodiment, the angle θ may be 76 degrees.

[0028] 3 shows a top perspective view of an impeller cap 102 for a hollow shaft impeller 100, according to an embodiment of the present disclosure. The impeller cap 102 has a surface 150 for sealing the hollow shaft impeller 100 from fluids during use. The impeller cap 102 also includes a groove 103 for receiving a gasket 104. The impeller cap 102 optionally includes a stud 152 for locking the impeller cap 102 into the hole 144 in the hub 130 (best shown in FIG. 4). The impeller cap 102 may further include a cap beam 148 and a cap slot 153 for locking with a corresponding hub beam 155 and hub slot 146 (best shown in FIG. 4). More specifically, cap beam 148 may be configured to be disposed within hub slot 146, and hub beam 155 may be configured to be disposed within cap slot 153 when impeller cap 102 is removably coupled to hollow impeller housing 120.

[0029] FIG. 4 shows a top perspective view of a portion of a hub 130 for a hollow shaft impeller 100, according to an embodiment of the present disclosure. The hub 130 includes an upper portion 157 and a lower portion 159 having an interior volume 128 (as described above with reference to FIG. 1 ). The upper portion 157 of the hub 130 meets the lower portion 159 of the hub 130 at a bottom edge 149. As shown, an impeller retainer 106 including a boss 107 is mounted inside the interior volume 128 of the hub 130. Although not shown, a circular magnet 108, described above and illustrated in FIG. 1 , is held in place within the interior volume 128 of the hub 130 by the impeller retainer 106. As previously described, the circular magnet 108 is configured to be keyed to a cylinder 116 that protrudes from the bottom circular surface 110b of the circular flange 110. Thus, when disposed within the interior volume 128 of the hub 130, the circular magnet 108 is disposed below the circular flange 110 of the impeller retainer 106. The boss 107 of the impeller retainer 106 is configured to interact with the surface 150 of the impeller cap 102 to retain both the impeller retainer 106 and the circular magnet 108 disposed below the circular flange 110 of the impeller retainer 106 within the interior volume 128 of the hub 130 when the impeller cap 102 is coupled to the hub 130. This arrangement prevents the circular magnet 108 from moving up and down within the hollow shaft impeller 100. The circular flange 110 of the impeller retainer 106 further functions to center the circular magnet 108 within the interior volume 128 of the hub 130.

[0030] FIG. 5 shows a side perspective view of a bioprocessing system 200 including a disposable bioreactor bag 202 and a hollow shaft impeller 100 having impeller blades 134 with fins 140, according to an embodiment of the present disclosure. The bioprocessing system 200 further includes a rotatable shaft having a first end and a second end, the rotatable shaft having a vertical axis of rotation, as known to those skilled in the art. The bioreactor bag 202 may have an internal volume of 10 liters (L) to 10,000 L. In some embodiments, the bioreactor bag 202 further includes baffles 204 for enhanced mixing. Impeller embodiments disclosed herein include a hollow shaft and fins on the impeller blades. It should be noted that the hollow shaft impeller 100, with or without fins on the blades, is particularly effective for bioreactors having internal volumes greater than 200 L.

[0031] FIG. 6 illustrates a graph showing the tilt parameter of an impeller at 105 RPM, according to an embodiment of the present disclosure. The tilt parameter is a dimensionless number that quantifies the amount of tilt experienced by the impeller itself. To quantify the limit of tilt, the impeller was pushed down until the blades touched the side of the tank or cup, which is considered the worst-case or maximum tilt parameter. The data for the graph in FIG. 6 was generated from a four-pitch hollow shaft impeller 100 having impeller blades 134, each further comprising one fin 140 located in the center of the impeller blade 134. As shown, three different sizes of fins 140 were tested. The tested impeller size had a 16-inch diameter and, in one exemplary embodiment, was installed in a 2000 L bioreactor bag 202. The data for the graph in FIG. 6 represent the different amounts of impeller wobble experienced by hollow shaft impellers 100 having different sizes of fins 140. All three of the differently sized fins 140 demonstrated acceptable tilt parameters up to 105 RPM, an improvement over other impellers, including hollow shaft impellers that did not include stabilizer fins. The smallest fin 140 dimension studied was approximately 21.9 cm. 2 or 3.4in2 The small fin studied has a fin area of ​​approximately 41.3 cm 2 or 6.4in 2 The large fin studied has a fin area of ​​approximately 69.7 cm 2 or 10.8in 2 The bars in the graph of Figure 6, from left to right, are: no fins, smallest fins located in the center of the blades, small fins located in the center of the blades, and large fins located in the center of the blades. As shown in the graph of Figure 6, the small fins are particularly effective and provide the best improvement in impeller tilt / wobble.

[0032] All ranges of formulations listed herein include ranges therebetween and can include or exclude endpoints. Optionally included ranges are from integer values ​​therebetween (or including one original endpoint) and are in the recited order of magnitude or the next smaller order of magnitude. For example, if the lower range value is 0.2, optionally included endpoints can be 0.3, 0.4, ... 1.1, 1.2, etc., and 1, 2, 3, etc.; if the higher range is 8, optionally included endpoints can be 7, 6, etc., and 7.9, 7.8, etc. One-sided boundaries such as 3 or greater also include consistent boundaries (or ranges) starting from the recited order of magnitude or an integer value one order smaller. For example, 3 or greater includes 4 or 3.1 or greater.

[0033] Throughout this specification, references to "one embodiment," "a particular embodiment," "one or more embodiments," "an embodiment," or "an embodiment" indicate that a feature, structure, material, or characteristic described in connection with the embodiment is included in at least one embodiment of the present disclosure. Thus, appearances of phrases such as "in one or more embodiments," "in a particular embodiment," "in one embodiment," "in an embodiment," or "in an embodiment" throughout this specification are not necessarily referring to the same embodiment.

[0034] While certain embodiments have been described above, other implementations and applications are within the scope of the following claims. While the specification has been described with reference to particular embodiments, it is to be understood that these embodiments are merely illustrative of the principles and applications of the present disclosure. Accordingly, it is to be further understood that numerous modifications may be made to the illustrative embodiments and that other arrangements and patterns may be devised without departing from the spirit and scope of the embodiments in accordance with the present disclosure. Furthermore, the particular features, structures, materials, or characteristics may be combined in any suitable manner in any one or more of the embodiments.

[0035] The patent applications and patents and other non-patent publications cited herein are incorporated by reference in their entirety, throughout the entirety of the portion cited, to the same extent as if each individual publication or reference was specifically and individually indicated to be incorporated by reference herein as if fully set forth. Any patent application to which this application claims priority is also incorporated by reference herein in the manner described above for publications and references.

Claims

1. A hollow shaft impeller, a hollow impeller housing having a hub defining an interior volume and an impeller bore providing access to the interior volume; a magnet sized to be placed within the interior volume; an impeller cap removably coupled to the hollow impeller housing adjacent the impeller bore; an impeller retainer removably coupled to the magnet and dimensioned to be disposed within the interior volume, The impeller retainer includes: a circular flange having a top surface and an opposite bottom surface; a boss protruding from an upper surface of the circular flange, the boss configured to interact with the impeller cap when the impeller retainer is disposed within the interior volume, the magnet being disposed below the circular flange; and Equipped with the impeller retainer; a plurality of impeller blades projecting from the hub; A hollow shaft impeller comprising:

2. The hollow shaft impeller of claim 1 , wherein the plurality of impeller blades comprises three, four, or five impeller blades.

3. The hollow shaft impeller of claim 1 , further comprising at least one fin disposed on each impeller blade of the plurality of impeller blades.

4. 4. The hollow shaft impeller of claim 3, wherein at least one fin is triangular in shape.

5. The hollow shaft impeller of claim 3 , wherein the at least one fin is disposed on each impeller blade of the plurality of impeller blades between a top edge and a bottom edge of each impeller blade of the plurality of impeller blades.

6. 4. The hollow shaft impeller of claim 3, wherein at least one fin is disposed on and extends from a blade face of each impeller blade of the plurality of impeller blades.

7. The hollow shaft impeller of claim 1 , further comprising a gasket coupled to the impeller cap and configured to, together with the impeller cap, seal an interior volume in the impeller bore.

8. 8. The hollow shaft impeller of claim 7, wherein the gasket is an O-ring.

9. The hollow shaft impeller of claim 7 , wherein the gasket comprises an elastomeric material.

10. 10. The hollow shaft impeller of claim 9, wherein the elastomeric material is a vinyl material, a polyethylene material, a polypropylene material, a nylon material, a silicone material, a polytetrafluoroethylene material, or a rubber material.

11. The impeller retainer is The hollow shaft impeller of claim 1 further comprising a cylinder depending from a bottom surface of the circular flange.

12. The impeller retainer cylinder is 12. The hollow shaft impeller of claim 11, comprising a plurality of rails disposed about the outer surface of the cylinder.

13. The magnet is a bore disposed at the center of the magnet; 13. The hollow shaft impeller of claim 12, further comprising a plurality of slots disposed around the circumference of the bore.

14. A hollow shaft impeller as described in claim 13, wherein the rails of the cylinder are keyed to the slots, the bore at least partially receives the cylinder of the impeller retainer, and the slots at least partially receive the rails of the cylinder.

15. 15. The hollow shaft impeller of claim 14, wherein the magnet is coupled to the impeller retainer when the cylinder and the plurality of rails of the impeller retainer are disposed within the bore and plurality of slots of the magnet.

16. The impeller cap is The hollow shaft impeller of claim 1 , comprising a cap beam and a cap slot disposed about the impeller cap.

17. The impeller bore of the hollow shaft impeller is 17. The hollow shaft impeller of claim 16, comprising a hub beam and a hub slot disposed about the impeller bore, the cap beam configured to be disposed within the hub slot, and the hub beam configured to be disposed within the cap slot when the impeller cap is coupled to the hollow impeller housing.

18. A hollow shaft impeller as described in claim 1, wherein when the impeller retainer is positioned within the internal volume and removably coupled to the magnet, the impeller retainer extends through the internal volume between the cap and the magnet so as to center the magnet within the internal volume and prevent movement of the magnet across the internal volume.

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