FLEXIBLE FLUID VESSEL AND RELATED METHODS

Abstract

An apparatus for receiving a fluid is disclosed. The apparatus comprises an at least partially flexible vessel. The vessel includes a top wall and a plurality of sidewalls, a first of said sidewalls having a first length in a first plane that is greater than a second length of the second, generally orthogonal sidewall in the first plane, and a bottom wall depending from the at least two sidewalls. The vessel may have a generally rectangular cross section, and may include a depending portion. The vessel may be at least partially rigid. Related methods are also disclosed.

Description

TECHNICAL FIELD

This disclosure relates generally to the fluid handling arts and, more particularly, to a flexible fluid vessel and related methods.

BACKGROUND OF THE INVENTION

Modern fluid processing applications often employ disposable vessels for at least temporarily receiving and containing the fluid. For example, in the course of bioprocessing, hermetically sealed bags formed of flexible plastic film are often used for bulk intermediate storage, cell culture re-suspension, viral inactivation, final formulation, final fill, or as bioreactors. In any case, such vessels or bags generally come in two shapes, cylindrical and cubical, typically have a flat bottom, and universally require some form of external support structure, such as a rigid outer tank, during use.

When positioned in a tank and filled with fluid, flexible vessels that are cylindrical or cubical have a tendency for improper seating, which results in separation from the sidewalls, and especially along the lowermost corners. An example of this tendency is illustrated in FIGS. 1-3, which schematically depict a cubic bag B in an outer tank K. Aside from lacking aesthetic appeal, this separation results in gaps G and folds F or creases in the flexible walls, which can not only impair the flow of fluid within the bag B and create crevasses where debris can become trapped, but also tend to stress the material and increase the chance of deleterious perforation. Such flat-bottomed vessels when used with a mixer M positioned along the floor (see FIG. 2) also generally require a significant minimum amount of fluid to be present in order for the mixer to become submerged prior to commencing the mixing operation. Draining the fluid from a flat-bottomed vessel may also pose an issue, since the flat floor does not in any way help to guide the fluid toward a stationary floor drain, regardless of its relative positioning.

Thus, a need is identified for a manner of providing an improved flexible vessel, such as a mixing bag. The vessel would be capable of use in addressing a variety of different requirements for fluid processing operations, including the proper seating of the vessel in any outside tank or like support structure, mixing with less fluid that would be required with a flat-bottomed vessel, and improved draining of the fluid. The vessel would also be relatively easy to create and implement. Overall, use of the improved vessel would thus lead to a simplification of the fluid processing and a concomitant reduction in the expense associated with such use.

SUMMARY

According to one aspect of the disclosure, an apparatus for receiving a fluid comprises an at least partially flexible vessel including a top wall and a plurality of sidewalls. A first of the sidewalls includes a first length in a first plane that is greater than a second length of the second, generally orthogonal sidewall in the first plane, and a bottom wall depending from the at least two sidewalls. The vessel may thus be rectangular in cross-section and, in particular, may have a generally continuous rectangular cross-section from the top wall to the bottom wall. The area of the cross-section may instead generally decrease continuously from a lowermost portion of the sidewalls to a vertex of the bottom wall.

In one embodiment, the bottom wall of the vessel is flexible, but it may be fully or partially rigid instead. In another embodiment, the bottom wall may comprise at least two generally triangular panels. In still another embodiment, the bottom wall may comprise at least two generally trapezoidal panels. The bottom wall may also comprise at least four generally triangular panels or at least four generally trapezoidal panels.

The bottom wall may comprise a central region including a generally flat upper surface, which may be formed by a rigid portion. The rigid portion may include at least one port. The rigid portion may be at least partially transparent.

The vessel may include a bottom weld for connecting at least part of the bottom wall to at least one of the sidewalls. The bottom weld may form an angle of less than 45 degrees relative to the sidewall in at least a folded state. The vessel may include a bottom K weld that is less than 45 degrees, and a top K-weld that is 45 degrees or more. More generally, the vessel may include a top K weld having an angle that is greater than the angle of the bottom weld. The vessel in a folded position may also include a side comprising a first length of a bottom portion, an intermediate portion having a second length, and a third length of a top portion, wherein the first length is greater than the third length.

Another aspect of this disclosure pertains to an apparatus for receiving a fluid. The apparatus comprises an at least partially flexible vessel including an upper portion having a generally rectangular body and a generally tapered portion depending therefrom.

Still a further aspect of this disclosure pertains to an apparatus for receiving a fluid. The apparatus comprises a vessel having at least one sidewall and a bottom wall having a non-circular shape. The sidewall may be flexible and the bottom wall may be rigid.

Yet another aspect of the disclosure pertains to an apparatus for receiving a fluid, comprising a vessel having at least one flexible sidewall and a rigid bottom wall having at least two generally triangular panels. The bottom wall may include at least two generally trapezoidal panels and possibly four generally triangular panels.

The disclosure also pertains to an apparatus for receiving a fluid, comprising a vessel having at least one flexible sidewall and a rigid bottom wall having at least four trapezoidal panels.

A further aspect of this disclosure is an apparatus for receiving a fluid, comprising a bag having a bottom K weld that is less than 45 degrees. The bottom K weld may be between about 40 and about 44 degrees. The bottom K weld may be about 41 degrees.

This disclosure also relates to an apparatus for receiving a fluid, comprising a vessel in the form of a bag having a top K weld with an angle, θ, and a bottom K weld with an angle, β, wherein θ>β.

Another aspect of the present disclosure pertains to an apparatus for receiving a fluid, comprising a bag that in an inflated condition forms a generally rectangular structure, and in a folded condition includes a side having a dimension defined by a first portion T, a second portion B, and an intermediate portion I between the first and second portions, wherein T<B.

Any apparatus described herein may further include a support structure for receiving the vessel. The support structure may comprise an interior matching the contour of at least a lower portion of the vessel. The vessel may further include a mixer, a sparger, a sensor, a drain, or any combination of the foregoing.

Still a further aspect of the disclosure is an apparatus for holding a fluid. The apparatus comprises a vessel including an at least partially flexible body having a depending portion comprising a plurality of first panels; and a support structure comprising a floor having a surface corresponding to each of the plurality of first panels.

This disclosure also has as one of any objects the provision of a collapsible mixing vessel including four generally planar and vertically extending side panels and a sloped floor. At least two of the side panels may be generally rectangular, and at least one of the side panels may be generally square.

A collapsible mixing vessel comprising a flexible upper portion connected to at least two sloping panels forming a floor also forms a part of this disclosure. The floor may be at least partially rigid.

This disclosure also pertains to processes, such as a method of forming a vessel for receiving a fluid. The method comprises forming a depending portion of the vessel by connecting a first panel of film adapted to form a bottom of the vessel to a second panel of film also adapted to form the bottom of the vessel at an angle of less than 45 degrees.

Another aspect of the disclosure relates to a method of forming a vessel for receiving a fluid, comprising connecting a plurality of panels of film to provide the vessel with an upper portion comprising a non-circular body having a generally tapered depending portion.

A method of processing a fluid may comprise placing the disclosed vessel in a tank including a floor having a contour matching the shape of the bottom wall.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1-3 are photographs illustrating one problem to be addressed by the disclosure.

FIGS. 4-6 provide various views of fluid vessels according to the disclosure.

FIGS. 7 and 8 illustrate further views of fluid vessels.

FIGS. 9-11 illustrate additional aspects of the disclosure.

DETAILED DESCRIPTION

Reference is now made to FIGS. 4-5, which illustrate a vessel 10 for receiving a fluid, such as for processing. The vessel 10 includes a bottom wall 12, a plurality of sidewalls 14, and a top wall 16. These structures combine to form a generally rectangular body having a first dimension, such as the length L, greater than a second, generally orthogonal dimension, such as the width W, in a common plane, such as a horizontal plane P coextensive with the lower terminus of the sidewalls 14.

At least one of the components of the vessel 10 may be flexible, such as for example the sidewalls 14. In one particularly preferred embodiment, all of the walls 12, 14, 16 are flexible. Thus, thus the vessel 10 takes the form of a flexible bag (but for purposes of this disclosure, the term bag may cover a vessel with one or more rigid walls or rigid portions as well). Consequently, the vessel 10 may collapse when not filled with the fluid.

In accordance with one aspect of the disclosure, the bottom wall 12 of the vessel 10 is arranged to form a depending portion. For example, the bottom wall 12 may depend from the plane P and generally taper in a direction toward an axis extending through the center of the vessel but away from the major plane of the corresponding sidewall 14. Consequently, the bottom wall 12 forms the depending portion generally in the shape of a polyhedron (if the portion associated with plane P were a solid surface). In the illustrated embodiment, this polyhedron is generally an inverted pyramid, which includes four sides or panels, with two sides 12a, and 12b generally forming triangles, and two sides 12c and 12d generally forming trapezoids. The result at the interface between the four ends of the panels 12a-12d is a seam 18 extending in the longitudinal direction L, and defining a vertex essentially located at a central region 22 on the bottom of the vessel 10.

The presence of this seam 18 in the illustrated embodiment may dictate that any port, such as for a drain, inlet, sensor, probe, or the like, should be provided at an offset or non-centered location along the sloping floor formed by the bottom wall 12. Thus, as shown in FIGS. 4 and 5, one or more openings 20 may be provided on bottom side panel 12d, as well as on the opposite panel 12c. As should be appreciated, the opening 20 when serving as a drain should be positioned as close to the vertex defined by seam 18 as possible, thus ensuring that the sloping panels 12a-12d of the bottom wall 12 help to maximize the volume of fluid that flows through the drain when emptying of the vessel 10 is desired. Also, when a mixer M is present in the bottom portion of the vessel 10, including the sloping panels 12a-12d forming the bottom wall 12, it should be appreciated that a lesser volume of fluid is required to submerge the mixer, as contrasted with employing a vessel having a completely flat or planar bottom.

FIG. 5 shows an exemplary vessel 10 made according to the disclosure in a folded or flat condition, such as is usually the result just after manufacturing and prior to use (normally after inflation with a fluid). Fabrication of the vessel 10 generally requires securely connecting together multiple panels of film, such as by welding, adhesive, or the like. The film panels are sized and shaped so as to provide the resulting vessel 10 with the generally rectangular shape in cross-section when inflated.

In the preferred embodiment, the connection among the film panels is made by welding, including along the portions of film that ultimately form the portions of the vessel 10 including the bottom wall 12 and the top wall 16. These welds, typically referred to as “K welds” are placed such that they are at an angle, β, relative to an axis associated with the longitudinal dimension of the sidewall 14, which angle is less than 45 degrees (which may be considered a “K weld” of less than 45 degrees). In one particular embodiment, the angle is between 40-45 degrees, and may be more specifically 41 degrees. The angles of the K welds on the opposite sides of the bottom of the folded vessel 10 may be equal or unequal, depending on the desired configuration.

Similar K welds may be provided for forming the top of the vessel 10. However, the angle, θ, of one or both of the top K welds may be greater than that of the bottom welds. The angle θ of the top welds may be 45 degrees or greater. As with the bottom welds, the top welds may be the same for each side of the vessel 10, or may be different, depending on the situation.

As a consequence of this arrangement, the resulting vessel 10 when folded includes a side with a total length H that can be defined as an intermediate portion I plus a top length T and a bottom length B, where B>T. When the vessel 10 is inflated, it will thus have the shape generally described above, with a lower portion formed by the bottom wall 12 depending from the terminus of the sidewalls 14 and a generally planar top wall 16.

When used in a similarly shaped support structure, such as a tank 24 having an interior surface generally corresponding to the shape of the vessel 10, as shown in cross-section in FIG. 7 (and with the understanding that the floor of the tank 24 may include one or more openings for receiving drive units, tubing, port fitments, etc.), it has been discovered that the tendency of the sidewalls 14 to slouch or peel away from the corresponding walls of the tank 24 may be eliminated, or at least reduced considerably. Consequently, the incidence of undesirable folds is likewise kept in check and a more tidy arrangement is presented. While optional, matching the contour of the floor of the tank 24 with the welds along the bottom portion of the vessel 10 may also help to reduce stress. The non-circular shape of the interior compartment also may avoid the creation of the usually undesirable vortices in the fluid that may result from agitation using a mixer or the like, especially when located in the center of the vessel.

FIG. 8 illustrates that the bottom wall 12 of the vessel 10 may also comprise a rigid material 26. This may be instead of or in addition to a piece of film also forming all or a portion of the bottom wall 12, but one approach may be for the rigid material 26 to connect directly to the sidewalls 14, such as by welding (and perhaps with overlapping to help ensure the seal is formed in the desired manner). The material 26 may be formed having a polyhedral shape, such as a pyramid as described above with respect to the bottom wall 12 formed of the flexible film.

FIGS. 9 and 10 illustrate a further embodiment in which the rigid or flexible bottom wall 12 of the vessel 10 forms a depending portion, as with the other embodiments described herein. In this embodiment, the central region 22 formed by the concurrence of the panels 12a-12d forming the bottom wall 12 is oversized as compared to the FIG. 4 embodiment, and may take the shape of a rectangle in top plan view (FIG. 10). Thus, the bottom wall 12 is formed of four generally trapezoidal panels 12a-12d in this embodiment. This central region 22 may thus receive or support any hardware, such as a drain, mixer, sparger, sensor or the like. In the case of a drain, it should be appreciated that the sloping interior surfaces of the panels 12a-12d help to guide the fluid toward the generally flat center of the bottom wall 12, thereby improving efficiency and effectiveness. As should be further appreciated, the view of FIG. 10 could apply equally to a rigid tank for receiving and providing support for the completely flexible vessel 10.

FIG. 11 indicates that the center region 22 may comprise, in whole or in part, a generally flat wall, such as formed by a rigid plate 28. This plate 28 may also be at least partially transparent, such as for allowing light to pass for contacting an optical sensor in contact with the fluid in the vessel, or allowing for observations, such as through an external microscope or like device. Various ports 20 may also be provided in the plate 28 for drains, supports for mixers, gas input, or the like. In this embodiment, the entire bottom wall 12 may take the form of a rigid cup-shaped structure to which the film forming the sidewalls 14 is attached.

In use, the vessel 10, especially when in the form of a flexible bag, is generally sealed for use under sterile conditions. Any ports through which additions are made to the interior compartments may include sterile connectors or filters to help ensure the sterile conditions.

The foregoing descriptions of several embodiments made according to the disclosure of certain inventive principles are presented for purposes of illustration and description. The embodiments described are not intended to be exhaustive or to limit the invention to the precise form disclosed and, in fact, any combination of the components of the disclosed embodiments is contemplated. The term “flexible” as used herein in the context of the vessel refers to a structure of the vessel that, in the absence of auxiliary support, may conform to the shape of the fluid contained in the vessel, as contrasted with a “rigid” structure, which retains a pre-determined shape when the fluid is in the vessel. Terms like “about,” generally,” and “substantially” mean that a particular item, such as an amount, may vary slightly from a precise definition. Modifications or variations are possible in light of the above teachings. For example, various materials may be used to form the vessel in any combination, including polymers (such as, for example, polypropylene for any flexible portions, and high density polyethylene for any rigid portions). The embodiments described were chosen to provide the best illustration of the principles of the invention and its practical application to thereby enable one of ordinary skill in the art to utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. All such modifications and variations are within the scope of the invention when interpreted in accordance with the breadth to which it is fairly, legally, and equitably entitled.

Claims

1. An apparatus for receiving a fluid, comprising: an at least partially flexible vessel including a top wall and a plurality of sidewalls, a first of said sidewalls having a first length in a first plane that is greater than a second length of the second, generally orthogonal sidewall in the first plane, and a bottom wall depending from the at least two sidewalls.

2. The apparatus of claim 1, wherein the vessel comprises a rectangular cross-section.

3. The apparatus of claim 1, wherein the vessel comprises a generally continuous rectangular cross-section from the top wall to the bottom wall.

4. The apparatus of claim 3, wherein the area of the cross-section generally decreases continuously from a lowermost portion of the sidewalls to a vertex of the bottom wall.

5. The apparatus of claim 1, wherein the bottom wall of the vessel is flexible.

6. The apparatus of claim 1, wherein the bottom wall of the vessel is rigid.

7. The apparatus of claim 1, wherein the bottom wall of the flexible vessel comprises at least two generally triangular panels and at least two generally trapezoidal panels.

8. The apparatus of claim 1, wherein the bottom wall comprises at least four generally triangular panels.

9. The apparatus of claim 8, wherein the bottom wall comprises at least four generally trapezoidal panels.

10. The apparatus of claim 1, wherein the bottom wall comprises a central region including a generally flat upper surface.

11. The apparatus of claim 10, wherein the central region is formed by a rigid portion.

12. The apparatus of claim 11, wherein the rigid portion includes at least one port.

13. The apparatus of claim 11 wherein the rigid portion is at least partially transparent.

14. The apparatus of claim 1, wherein the vessel includes a bottom weld for connecting at least part of the bottom wall to at least one of the sidewalls, wherein the bottom weld forms an angle of less than 45 degrees relative to the sidewall in at least a folded state.

15. The apparatus of claim 1, wherein the vessel includes a bottom K weld that is less than 45 degrees.

16. The apparatus of claim 14, wherein the vessel includes a top K weld that is 45 degrees or more.

17. (canceled)

18. The apparatus of claim 1, wherein the vessel in a folded condition includes a side comprising a first length of a bottom portion, an intermediate portion having a second length, and a third length of a top portion, wherein the first length is greater than the third length.

19.-28. (canceled)

29. An apparatus for receiving a fluid, comprising a vessel in the form of a bag having a top K weld, Θ, and a bottom K weld, β, wherein Θ>β.

30.-39. (canceled)

40. A method of forming a vessel for receiving a fluid, comprising: forming a depending portion of the vessel by connecting a first panel of film adapted to form a bottom of the vessel to a second panel of film also adapted to form the bottom of the vessel at an angle of less than 45 degrees.

41.-42. (canceled)

43. The apparatus of claim 16, wherein the vessel includes a top K weld having an angle that is greater than the angle of the bottom weld.