Apparatus, system and method for reducing minimum operating volume of bioreactor

Abstract

An apparatus (30) for reducing a minimum working volume of an agitator tank (12) includes a body (32) having an upper surface (46) and a lower surface (48), and an outer profile shaped to fit closely within an interior of the agitator tank. The body includes an interior portion (34) extending through the body (32) from the upper surface to the lower surface, the interior portion configured to receive and partially surround an impeller (200) within the agitator tank while allowing the impeller to rotate to agitate fluid in the vessel in use. The body further includes an opening in a side surface of the body that extends into the interior portion and is configured to facilitate removal of fluid (60) from the vessel and from the agitator tank via the drain port when the agitator tank is in use.

Description

Technical Field

[0001] Embodiments of the present invention relate generally to mixer and bioreactor systems and methods, and more particularly, to apparatus, systems, and methods for selectively reducing the minimum working volume of a stirred tank mixer / bioreactor. Background Art

[0002] Mixers and bioreactors are commonly used to carry out biochemical and biological processes and / or to process liquids and other products of such processes. These devices typically use single-use vessels, such as flexible or collapsible plastic bags supported by an external rigid structure (such as a stainless steel housing or tank). As will be appreciated, the use of sterile single-use bags eliminates the time-consuming step of cleaning the tank after each use and reduces the chance of contamination.

[0003] In use, the disposable bag is positioned within the rigid canister and filled with the desired fluid for mixing / processing. An impeller assembly including a rotating impeller having one or more blades is disposed within the bag and is used to agitate or mix the fluid. Existing impeller systems are either top driven, having a shaft extending downwardly into the bag with one or more impellers mounted thereon, or bottom driven, having an impeller disposed in the bottom of the bag, the impeller being driven by, for example, a magnetic drive system positioned external to the bag and / or vessel.

[0004] Such mixers / bioreactors have minimum and maximum working volumes, i.e., the range of operating fluid volumes over which the device can effectively carry out biological / biochemical processes. The ratio of maximum working volume to minimum working volume is called turndown ratio. For example, in current systems, for a turndown ratio of about 1:3, the minimum working volume can be about 33% of the maximum working volume. However, as will be appreciated, operational flexibility is highly desirable, and the higher the turndown ratio, the larger the acceptable range of fluid volumes.

[0005] More specifically, biopharmaceuticals have high value, so it is desirable to only manufacture the biopharmaceuticals needed and minimize waste. However, known mixers and bioreactors are operated with fixed turndown ratios, and larger tanks / housings may have a minimum working volume that is not suitable for mixing / processing smaller volumes. If reactors or mixers have low turndown ratios, then additional biomaterials may be needed, for example, large-scale culture cultivation, and / or multiple reactors / mixers may be needed. As will be appreciated, additional reactors / mixers require additional bags, larger facilities, and generally will increase operating costs.

[0006] In view of the foregoing, there is a need for an apparatus, system, and method for selectively reducing the minimum working volume of a mixer / bioreactor. Summary of the invention

[0007] Some embodiments commensurate with the scope of the originally claimed subject matter are summarized below. These embodiments are not intended to limit the scope of the claimed subject matter, but these embodiments are only intended to provide a brief overview of possible embodiments. In fact, the present disclosure can encompass various forms that may be similar or different from the embodiments set forth below.

[0008] In one embodiment, an apparatus for reducing the minimum working volume of a mixing tank includes a body having an upper surface and a lower surface, and an outer profile shaped to fit tightly within the interior of the mixing tank. The body includes an inner portion extending through the body from the upper surface to the lower surface, the inner portion being configured to receive and partially surround an impeller within the mixing tank while allowing the impeller to rotate to agitate the fluid in the vessel when in use. The body further includes an opening in a side surface of the body extending into the inner portion and configured to allow fluid to exit the body when the mixing tank is in use and be removed from the mixing tank via a drain.

[0009] In another embodiment, a mixing tank includes an internal volume configured to receive a vessel having a vessel interior that accommodates a rotatable impeller, the vessel interior configured to receive a fluid. The mixing tank further includes a body located within the internal volume of the mixing tank, the body having an upper surface and a lower surface and an internal portion extending through the body, the internal portion configured to receive and partially surround an impeller of a vessel placed within the mixing tank, while allowing the impeller to rotate to agitate the fluid in the mixing tank when in use, the body further including an opening in a side surface of the body, the opening extending into the internal portion and configured to allow the fluid to partially exit the internal portion when the mixing tank is in use and be removed from the vessel via a drain in the mixing tank. The body can be selectively removed from the internal volume or added to the internal volume to increase or decrease the minimum working volume of the mixing tank.

[0010] In yet another embodiment, a method of reducing the minimum working volume in a mixing tank includes placing a body within the interior of the mixing tank, the body having an upper surface and a lower surface and an interior portion extending through the body, the interior portion being configured to receive and partially surround an impeller of a vessel placed within the mixing tank while allowing the impeller to rotate to agitate the fluid in the mixing tank when in use; the body further includes an opening in a side surface of the body, the opening extending into the interior portion and being configured to allow the fluid to partially exit the interior portion when in use and be removed from the vessel via a drain in the mixing tank.

[0011] In yet another embodiment, a method for increasing the minimum working volume in a mixing tank includes removing a body from the interior of the mixing tank, the body having an upper surface and a lower surface and an internal portion extending through the body, the internal portion being configured to receive and partially surround an impeller of a vessel placed in the mixing tank while allowing the impeller to rotate to agitate the fluid in the mixing tank when in use; the body further includes an opening in a side surface of the body, the opening extending into the internal portion and being configured to allow the fluid to partially exit the internal portion when in use and be removed from the vessel via a drain in the mixing tank. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The invention will be better understood by reading the following description of non-limiting embodiments with reference to the accompanying drawings, in which:

[0013] Figure 1 is a front perspective view of an exemplary mixer system suitable for use with embodiments of the present invention.

[0014] Figure 2 is a top perspective view of the interior of a mixing tank suitable for use with embodiments of the present invention.

[0015] Figure 3 is a front perspective view of a mixing tank with the mixing tank cut away to illustrate an apparatus for reducing the minimum working volume according to an embodiment of the present invention.

[0016] Figure 4 yes Figure 3 A top perspective view of a device of with the mixer tank, impeller and minimum working volume fluid removed for clarity.

[0017] Figure 5 yes Figure 4 Side view of the device.

[0018] Figure 6 yes Figure 4 An opposite side view of the device.

[0019] Figure 7 yes Figure 4 A top perspective view of a device showing a multi-component assembly according to an embodiment of the present invention.

[0020] Figure 8 yes Figure 7 Bottom perspective view of the device.

[0021] Fig. 9 is an enlarged perspective view of a handle according to an embodiment of the present invention.

[0022] Fig.10 is an enlarged perspective view of a connector according to an embodiment of the present invention.

[0023] Fig.11 is a diagrammatic illustration of an assembly method according to an embodiment of the present invention.

[0024] Fig.12 yes Figure 3 The impeller and the use of Figure 3 A top perspective view of the minimum working volume of liquid achieved by the device.

[0025] Fig.13 yes Fig.12 Minimum working volume and side view of the impeller.

[0026] Fig.14 yes Fig.12 Minimum working volume and enlarged side view of the impeller.

[0027] Fig.15 is a top perspective view of an apparatus for reducing a minimum working volume according to another embodiment of the present invention.

[0028] Fig.16 is a front perspective view of a mixer system tank with the mixer system tank cut away to show Fig.15 equipment and minimum working volume of fluid.

[0029] Fig.17 yes Fig.16 The impeller and the use of Fig.15 A top perspective view of the minimum working volume of liquid achieved by the device.

[0030] Fig.18 yes Fig.17 Minimum working volume and side view of the impeller.

[0031] Fig.19 yes Fig.17 Minimum working volume and enlarged side view of the impeller.

[0032] Fig. 20 yes Fig.15 A first side view of the device.

[0033] Fig.21 yes Fig.15 An opposite side view of the device.

[0034] Fig. 22 yes Fig.15 An enlarged perspective view of the handle of the device.

[0035] Fig.23 yes Fig.15 A top view of the device.

[0036] Fig.24A and 24B is an illustration of a low-profile impeller that is particularly suitable for use with embodiments of the present invention.

[0037] Fig.25 is an enlarged perspective view of a vessel suitable for use with embodiments of the present invention, depicting an impeller within the interior volume of the vessel. DETAILED DESCRIPTION

[0038] Reference will now be made in detail to exemplary embodiments of the present invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference symbols are used throughout the drawings to refer to the same or like parts.

[0039] As used herein, the terms "flexible" or "collapsible" refer to structures or materials that are pliable or capable of bending without breaking, and may also refer to compressible or expandable materials. An example of a flexible structure is a bag made of polyethylene film. The terms "rigid" and "semi-rigid" are used interchangeably herein to describe a "non-collapsible" structure, i.e., a structure that will not fold, collapse, or otherwise deform to significantly reduce its elongated dimensions under normal forces. Depending on the context, "semi-rigid" may also refer to a structure that is more flexible than a "rigid" element, such as a bendable tube or catheter, but is still a structure that will not collapse longitudinally under normal conditions and forces.

[0040] "Vessel" as that term is used herein refers to a flexible bag, a flexible container, a semi-rigid container, or a rigid container, as the case may be. The term "vessel" as used herein is intended to encompass mixer and bioreactor vessels having flexible or semi-rigid walls or wall portions, single-use flexible bags, and other containers or conduits commonly used in biological or biochemical processing, including, for example, cell culture / purification systems, mixing systems, media / buffer preparation systems, and filtration / purification systems.

[0041] As used herein, the term "bag" refers to a flexible or semi-rigid container or vessel that is used, for example, as a bioreactor or mixer for the contents thereof. In this regard, embodiments of the present invention are suitable for use with mixers, bioreactors, and other devices or systems for mixing or processing fluids.

[0042] As used herein, "stirred tank" refers to a tank, housing or vessel of a mixer, bioreactor, etc., which is configured to receive a fluid and mix, stir or otherwise agitate the fluid. The term is not limited to single-use mixers / bioreactors, but is intended to generally cover reactors and mixers, including those used in biological, chemical, industrial, environmental and other applications. The term is also not limited to a specific device or method for mixing, stirring or otherwise agitating a fluid. The term includes, but is not limited to, tanks of various sizes and shapes, including rectangular, square and cylindrical tanks.

[0043] refer to Figure 1 and 2, an exemplary mixer system 10 suitable for use with embodiments of the present invention is shown. The mixer system 10 includes a generally rigid stirred tank 12 (hereinafter referred to as "tank 12"), which is mounted on a base 14 that is movable via lockable casters 19. The base 14 has generally open sides 17 to allow a user to access the underside or bottom surface of the tank 12. The tank 12 can be formed of, for example, stainless steel, polymers, composite materials, glass, or other metals. As shown, in one embodiment, the tank 12 has a substantially rectangular shape. In other embodiments, the tank 12 can be a cylindrical bioreactor tank.

[0044] In operation, a single-use flexible container or bag 15 is disposed within the interior 23 of the can 12, which, among other functions, supports and protects the bag 15. As will be appreciated, the bag 15 has an interior volume 11 ( Fig.25 ), which receives the material (e.g., fluid) to be mixed / processed. To this end, the bag 15 includes an impeller 200 located within its interior volume 11. In an embodiment, the impeller 200 includes one or more permanent magnets that allow the impeller 200 to be magnetically coupled to the external impeller drive motor 16.

[0045] As shown, the external impeller drive motor 16 is located outside and below the tank 12 and is accessible through the open side 17 of the base 14. In an embodiment, the drive motor 16 is secured to the bottom surface 24 of the interior 23 of the tank 12. The interior 23 also includes a drain aperture or hole 18 located on the bottom surface 24 that allows the drain line from the bag 15 to pass through ( Figure 2 As will be appreciated, the drain 18 allows the contents of the bag 15 to be selectively removed.

[0046] The bottom surface 24 of the interior 23 further includes an impeller drive head 26, which in embodiments can be magnetically coupled to the magnets of the bag impeller, as previously mentioned. The interior 23 also features a probe window 20 through which a monitoring probe (e.g., pH, conductivity, temperature, etc.) can be inserted into the bag 15. Figure 1 The mixer 10 includes a controller 22 that allows a user to monitor the probe and control the operation of the mixer 10 , including any pumps connected to the mixer 10 .

[0047] Now turn to Figure 3 , the tank 12 is cut away to show the apparatus 30 for reducing the minimum working volume according to an embodiment of the present invention. The figure further depicts the impeller 200 and the reduced minimum working volume fluid 60. For clarity, the vessel or bag 15 is omitted, but in an embodiment, the vessel or bag 15 will contain the impeller 200 and the fluid 60.

[0048] The apparatus 30 includes a body 32 that, when in use, is seated on the bottom surface 24 of the interior 23 of the tank 12. The body 32 fits tightly within the tank interior 23 and is generally configured (e.g., shaped) to match the shape of the tank interior 23. In the depicted embodiment, the body 23 is rectangular to match the rectangular mixing tank 12. The body 32 further includes a substantially arcuate U-shaped or C-shaped interior portion 34 that partially surrounds the impeller 200, thereby reducing the minimum working volume 60 while allowing access to the drain 18 and the probe window 20 ( Figure 2 ).

[0049] Reference now Figure 4-8 , the body 32 has an outer profile that is shaped to fit tightly within the interior of the stirred tank 12. In the depicted embodiment, the outer profile of the body 32 is defined by four sides 36, 38, 42, 44, each side being at a substantially 90 degree angle to an adjacent side, thereby creating a generally quadrilateral shape. As will be appreciated, the shape of the outer profile of the body 32 may vary depending on the shape of the interior of the tank. For example, the body 32 may have a circular or substantially circular outer profile for use in known cylindrical reactor tanks.

[0050] The body 32 further includes an upper surface 46 and a bottom or lower surface 48 ( Figure 8 The interior portion 34 of the body extends through the body 32 from the upper surface 46 to the lower surface 48, thereby creating an open body section that partially surrounds the impeller of the vessel (eg, bag) and allows the impeller to rotate to mix / agitate the fluid in the vessel.

[0051] The body 32 includes an opening 50 extending into the interior portion 34. In an embodiment, the opening 50 is formed by a void, cutout, or other absence of material in one or more of the sides 36, 38 of the body 32. The opening 50 is configured to facilitate removal of fluid from the bag 15 when the canister 12 is in use, and from the canister via the drain 18. In an embodiment, the opening 50 allows access to the probe window 20 located on the front surface of the canister 12.

[0052] like Figure 4-6 , the inner portion 34 is a substantially continuous smooth surface. The surface is curved and arranged in a generally U-shape or C-shape. The surface is angled toward the opening 50 so that the fluid 60 in the bag 15 within the inner portion 34 is directed out of the opening 50 toward the drain 18 of the tank 12. The angle A of the surface can vary, and the shape can vary, but the shape and angle that directs the fluid toward the opening 50 and the drain 18 are desirable. In one embodiment, the angle A is about 30°.

[0053] Additionally, in certain embodiments, the surface 52 of the body 32 has an angle C of approximately 10°. The surface 52 is angled toward the opening 50 so that fluid does not settle on the surface 52 during operation.

[0054] Although the surface of the inner portion 34 is shown as continuous and smooth, e.g., without hard angles or flat portions, in certain embodiments it may have such a surface. That is, a continuous smooth surface as depicted requires less fluid to immerse the impeller 200, produces a lower minimum working volume 60, and helps ensure that the inner portion 34 does not scratch or puncture the bag 15 when in use.

[0055] In an embodiment configured for use with 50L, 100L, and 200L stirred tank mixers, the inner portion 34 has a base diameter B of 250 mm. In certain embodiments, a 25 mm space S is maintained between the tip of each impeller blade and the inner portion 34 (e.g., Fig.12 As will be appreciated, the diameter of the inner portion 32 may vary depending on the size and shape of the mixed tank 12, the apparatus 30, and the length of the impeller blades.

[0056] like Figure 12-14 , the impeller 200 is spaced apart from the inner portion 34, which defines the shape of the depicted minimum working volume fluid 60. Specifically, in one embodiment, the minimum working volume 60 is determined based on a 10 mm space between the highest point of the impeller 200 and the surface of the fluid 60.

[0057] Reference now Figure 5 and 6 In one embodiment, the body 32 has an overall wedge shape or profile. That is, the body 32 has a maximum height where the sides 42 and 44 meet to form a high corner 45 that is directly opposite the exposed corner of the can 12 containing the drain 18. These sides 42, 44 then taper down so that the other two corners 47 and 49 are lower than the high corner 45. The overall wedge shape and high corner 45 also serve to direct the fluid 60 in the bag 15 within the interior portion 34 toward the opening 50 and the drain 18 in the can 12.

[0058] In a particular embodiment configured for a 100L stirred tank 12, the body 32 has a width of 498 mm and a length of 498 mm, and a height of 186 mm. In an embodiment configured for use with a 50L tank, the body 32 has a length and width of 388.7 mm, and a height of 127 mm. For a 200L tank, the length and width of the body 32 is 630 mm, and a height of 275 mm. However, as will be appreciated, the outer dimensions of the body 32 may vary depending on the size of the interior of the reactor / mixing tank.

[0059] Furthermore, the body 32 is shaped to accommodate a can 12 having a bottom surface 24 that is angled 2° toward the corner of the can 12 having the drain 18. That is, the lower surface 48 of the body 32 may have a complementary angle such that the side walls 36, 38, 42, 44 are flush with the walls of the can 12.

[0060] Reference now Figure 7 , 10 In embodiments, the body 32 may be an assembly of multiple selectively interconnected body segments. In the depicted embodiment, the body 32 includes three such segments 76, 78, 80. The body segments 76, 78, 80 may be connected to one another via a connection mechanism that may include, for example, a protrusion 82 that slidably fits within a groove or channel 84 in an adjacent body segment. Fig.11 , the body 32 may be assembled by slidably connecting each segment 76, 78, 80 via a protrusion 82 and a groove 84. Various other connection mechanisms / methods may be employed without departing from the scope of the present invention.

[0061] As will be appreciated, the body 32 can be broken down into a more easily transportable form via the selectively interconnected body sections 76, 78, 80. This may be desirable for large mixer / bioreactors, where the body 32 is also relatively large. However, in certain embodiments, the body 32 may include less than or more than three sections. In certain other embodiments, the body 32 may include two sections, while in other embodiments, the body 32 may be integral.

[0062] The body 32 may also have one or more handles 41 to facilitate placement and removal of the body 32 in and from the can 12. As shown, in some embodiments, each body section 76, 78, 80 has its own handle 41, which may be a rectangular recess. In other embodiments, the handle may have a different shape / form, and in still other embodiments, there may be fewer handles (or no handles).

[0063] In certain 100L and 200L embodiments, the body 32 may include two 100mm wide by 20mm high handles, and a third handle that is 75mm wide by 16mm high. The fourth handle may be 20mm wide by 10mm high. In a certain 50L embodiment, the handle is 18mm wide by 15mm high. The exact dimensions (e.g., width and height) of the handle may vary depending on the size of the reactor / mixer tank and is within the scope of the present invention.

[0064] like Figure 8 , the body 32 may include a series of ribs 47. The ribs 47 serve to strengthen the body 32 and provide support for the body 32 when it is subjected to loads from the fluid in the tank 12. As will be appreciated, in embodiments, the body 32 may include more or fewer ribs than depicted, or may be solid.

[0065] In one embodiment, the device 30 may be made of a thermoplastic elastomer such as high density polyethylene (HDPE). Although HDPE may be suitable due to its high strength to density ratio, other materials may be used without departing from the invention. In certain embodiments, the device 30 may be made of nylon, polyurethane, or acrylonitrile butadiene styrene. The device 30 may be vacuum cast, molded, or additively manufactured.

[0066] Reference now Figure 15-23 , depicts an alternative embodiment of the inventive apparatus 130. As shown, the apparatus 130 includes a body 132 characterized by a substantially arcuate U-shaped or C-shaped inner portion 134 that partially surrounds the impeller 140, thereby reducing the minimum working volume 160 while allowing access to the drain 118. In this embodiment, the two depicted longer side portions 142, 144 have a length of 388.7 mm.

[0067] This embodiment, configured for a smaller mixing tank 112 (e.g., 50L), is unitary and features a series of notches 141 that serve as handles for placing and removing the apparatus 130 from the tank 112. When used in conjunction with the impeller 200, the apparatus 130 is capable of achieving a minimum working volume of 5.2L in a 50L mixing tank 112.

[0068] exist Figure 26-29 In a further embodiment shown, a reduced minimum working volume is achieved by modifying the bag 15. Fig.26 and 27In an example embodiment shown in FIG. 1 , bag 250 includes an inflatable compartment 258. Inflatable compartment 258 is constructed by welding a piece of bag material 257 to the inside of bag 250 around at least a portion of the bottom perimeter of the bag. In the example shown, bag material 257 is an elongated piece with its long edge welded to the inside of bag 250. Weld 259 can extend along a portion or all of the perimeter of the bottom of the bag. The bag further includes a first barb 252, which is welded to the bag and is configured to provide a fluid passage to the interior of the bag. A first end of a tube 254 is connected to the first barb 252 and is located inside the interior volume of the bag 250. A second barb 256 is welded to inflatable compartment 258 and is connected to the second end of tube 254.

[0069] As shown, when the bag 250 is inflated, the first weld 259 extends around at least a portion of the side wall of the bag 250 and the second weld 259 extends along the bottom of the bag. The welded structure creates an inflatable compartment 258.

[0070] To inflate (see Fig.26 ), the compartment 258 is inflated with gas. Gas is pumped into the top barb 252 welded to a portion of the bag 250. The top barb 252 is fluidly connected to a tube 254 located inside the bag 250. The tube 254 is further connected to the bottom barb 256, which is welded to the bag material 257 that creates the inflatable compartment 258. Conversely, to deflate (see Fig. 27 ), gas is pumped out of the inflatable compartment 258 through the barbs 252, 256 and the tube 254.

[0071] Similar to the above embodiment, when the inflatable compartment 258 is in the inflated state ( Fig.26 ), since compartment 258 occupies space at the bottom of the bag, the minimum working volume is reduced.

[0072] In a further exemplary embodiment, Fig.28 and 29 As shown, the bag 350 can be modified to have a varying cross-sectional area with one or more hinges / folds 352 along the length of the bag 350. To create a reduced minimum working volume, the hinges / folds 352 are unfolded (see FIG. Fig.28 ). In the expanded state, the minimum working volume is reduced because the cross-sectional area of ​​the bag 350 at its base is reduced. Conversely, the minimum working volume can be increased by collapsing / folding the hinge / fold 352 so that the bag 350 maintains a substantially constant cross-sectional area (see Fig.29 ).

[0073] Go to Fig.24A and 24B, a low profile impeller 200 may be used with the body 32. Conventional mixer impellers have a height of 108.3 mm. However, the impeller must be submerged in the fluid for effective mixing / agitation. Therefore, the lower the height of the impeller, the less fluid is required to rise above that height. In an embodiment, the low profile impeller 200 may have a height H of about 39 mm (and an impeller diameter D of 220.5 mm).

[0074] By itself, such an impeller 200 can provide a substantial reduction in the minimum operating volume from 32 L to 13.87 L in a 100 L stirred tank mixer. Notably, the combination of an embodiment of the present apparatus 30 with the impeller 200 results in a minimum operating volume of 6.4 L in the same 100 L stirred tank. It has also been found that the impeller 200 can provide comparable mixing / agitation performance when compared to taller impellers.

[0075] An impeller need not have a height of 39 mm to be effectively used with embodiments of the present invention. It is contemplated that an impeller having a height of less than about 108 mm may be sufficiently "low profile" to be beneficially used with the present apparatus 30. Of course, in embodiments, the apparatus 30 may be used with conventional, taller mixer impellers and still achieve a significant reduction in minimum working volume.

[0076] In embodiments, the device 30, 130 reduces the minimum working volume and speeds up mixing, i.e., the time taken to mix the minimum working volume with the body 32, 132 in place is shorter than the time taken to mix the minimum working volume without the body 32, 132. In a particular embodiment where the minimum working volume was 6.4 L with the body 32, 132 and impeller 200, the mixing time was found to be 15 seconds, compared to 20 seconds without the device 30, 130. In certain embodiments, such as those including the low profile impeller 200, very high turndown ratios can be achieved.

[0077] Aspects of the present invention also include a method of reducing the minimum working volume in a mixing tank 12, the method comprising placing a body 32, 132 within the interior of the mixing tank 12. As described above, the body 32, 132 has an upper surface 46 and a lower surface 48 and an interior portion 34 extending through the body 32, 132, the interior portion 34 being configured to receive and partially surround an impeller 200 of a vessel placed within the mixing tank 12 while allowing the impeller 200 to rotate to agitate the fluid 60 in the mixing tank 12. The body 32, 132 further includes an opening 50 in a side surface of the body 12, the opening 50 extending into the interior portion 34 and configured to allow the fluid 60 to partially exit the interior portion and be removed from the vessel via a drain 18 in the mixing tank 12 when in use.

[0078] Similarly, embodiments include a method of increasing the minimum working volume 60 in a mixing tank 12 by removing the body 32, 132 from within the interior of the mixing tank 12. As discussed, the body 32, 132 has an upper surface 46 and a lower surface 48 and an interior portion 34 extending through the body 32, 132, the interior portion 34 being configured to receive and partially surround an impeller 200 of a vessel placed within the mixing tank 12 while allowing the impeller 200 to rotate to agitate the fluid 60 in the vessel. The body 32, 132 further includes an opening 50 in a side surface of the body 12, the opening 50 extending into the interior portion 34 and being configured to allow the fluid 60 to partially exit the interior portion and be removed from the vessel via a drain 18 in the mixing tank 12 when in use.

[0079] As used herein, an element or step stated in the singular and beginning with the word "a" or "an" should be understood not to exclude the plural number of the element or step, unless such exclusion is explicitly stated. In addition, reference to "an embodiment" of the present invention should not be interpreted as excluding the existence of additional embodiments that also incorporate the described features. In addition, unless explicitly stated to the contrary, an embodiment that "comprises," "includes," or "has" an element or multiple elements having a particular property may include additional such elements that do not have that property.

[0080] Although the material sizes and types described herein are intended to define the parameters of the present invention, they are by no means limiting, but rather exemplary embodiments. Many other embodiments will become apparent to those skilled in the art upon reading the above description. Therefore, the scope of the present invention should be determined with reference to the appended claims and the full range of equivalents to which such claims are entitled. In the appended claims, the terms "including" and "wherein" are used as the colloquial language equivalents of the corresponding terms "comprising" and "wherein".

[0081] Moreover, in the following claims, terms such as "first," "second," "upper," "lower," "bottom," "top," etc. are used merely as labels and are not intended to impose numerical or positional requirements on their objects. Moreover, the following claim limitations are not written in a means-plus-function format and are not intended to be interpreted as such unless and until such claim limitations expressly use the phrase "means for" followed by a recitation of function without further structure.

[0082] This written description uses examples to disclose several embodiments of the invention, including the best mode, and also to enable a person skilled in the art to practice the embodiments of the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to a person skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal language of the claims.

Claims

1. A device (30, 130) for reducing the minimum working volume of a mixing tank (12), comprising: A body (32, 132) having an upper surface (46) and a lower surface (48) and an outer profile shaped to fit closely within the interior of the mixing tank (12), the body comprising: an inner portion (34) extending through the body (32, 132) from the upper surface (46) to the lower surface (48), the inner portion (34) being configured to receive and partially surround an impeller (200) within the mixing tank (12) while allowing the impeller (200) to rotate to agitate a fluid (60) in a vessel when in use; and An opening (50) in a side surface of the body (32, 132) extends into the interior portion (34) and is configured to facilitate removal of fluid (60) from the vessel and from the blending jar (12) via a drain (18) when the blending jar (12) is in use.

2. The device (30, 130) according to claim 1, wherein The impeller (200) is located within the interior volume (11) of the vessel in the mixing tank (12).

3. The device (30, 130) according to claim 1, wherein: The impeller (200) is a low profile impeller.

4. The device (30, 130) according to claim 1, wherein: The inner portion (34) has a substantially arcuate U-shape.

5. The device (30, 130) according to claim 1, wherein: The outer contour of the body (32, 132) is defined by four side portions (36, 38, 42, 44), each side portion forming a substantially 90 degree angle with an adjacent side portion (36, 38, 42, 44).

6. The device (30, 130) according to claim 5, wherein: The four sides (36, 38, 42, 44) converge to form three corners (45, 47, 49), wherein one corner (45) has a height greater than the heights of the other two corners (47, 49), so that the fluid (60) in the vessel in the inner portion (34) is directed toward the opening (50).

7. The device (30, 130) according to claim 1, wherein: The body (32, 132) includes a plurality of selectively interconnectable body sections (76, 78, 80).

8. The apparatus (30, 130) of claim 1, wherein: The body (32, 132) includes at least one handle (41).

9. The device (30, 130) according to claim 1, wherein: The inner portion (34) includes a substantially continuous smooth surface.

10. The device (30, 130) according to claim 1, wherein The stirred tank (12) is a mixer or a bioreactor.

11. The device (30, 130) according to claim 2, wherein: The vessel is a collapsible bag or a bioreactor bag.

12. The device (30, 130) according to claim 1, wherein: The main body (32, 132) is made of high-density polyethylene.

13. The device (30, 130) according to claim 1, wherein The outer contour of the main body (32, 132) is substantially circular.

14. A device for reducing the minimum working volume of a mixing tank (12), comprising: A bag (250) configured to fit within the mixing tank, the bag (250) comprising: a first barb (252) welded to the bag (250) and configured to provide fluid access to the interior of the bag (250); a tube (254) connected to the first barb (252) and located within the interior volume of the bag (250); an inflatable compartment (258) located within the interior of the bag (250) and positioned along the perimeter of the bottom of the bag (250); A second barb (256) is welded to the inflatable compartment and connected to the tube.

15. A device for reducing the minimum working volume of a mixing tank (12), comprising: A bag (350) configured to fit within the blending tank, the bag comprising: a plurality of folds or hinges (352) along the length of the bag (350), Wherein, when the folded portion or hinged portion (352) is in an unfolded or unhinged state, the bag (350) has a reduced cross-sectional area at its base.

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