Systems using a levitating, rotating pumping or mixing element and related methods

1. A mixing tank assembly for use in mixing a fluid under sterile conditions so as to avoid contamination or leakage, comprising:

a side wall having an interior surface at least partially bounding a chamber;

a floor disposed within or at the base of the chamber, the floor having an opening extending therethrough;

a flexible bag disposed within the chamber so as to rest on the floor, the flexible bag having an upper portion and a substantially continuous lower portion bounding a hermetically sealed compartment capable of holding the fluid under sterile conditions;

a mixer disposed within the compartment of the flexible bag; and

a shaft having a first end for receiving the mixer.

2. The assembly according to claim 1 , wherein the shaft projects through an aperture in the flexible bag, and further including a seal for sealing the shaft to the bag to prevent leakage.

3. The assembly of claim 1 , wherein the shaft comprises an oversized head portion.

4. The assembly of claim 1 , wherein the shaft is coupled to the mixer.

5. The assembly of claim 1 , wherein the shaft is positioned in a cavity formed in a side of the bag.

6. The assembly of claim 1 , wherein the shaft comprises a post integral with the bag.

7. The assembly of claim 1 , wherein the shaft includes a second end external to the bag.

8. A mixing tank assembly for use in mixing a fluid under sterile conditions so as to avoid contamination or leakage comprising:

a first container including a lower portion having an opening;

a hermetically sealed flexible bag disposed within the first container;

a mixer disposed within the flexible bag; and

a shaft having a first end for receiving the mixer and an opposing second end, said shaft being secured to said flexible bag.

9. The assembly of claim 8 , wherein the lower portion comprises the floor of the first container.

10. The assembly of claim 8 , wherein the lower portion comprises a sidewall of the first container.

11. The assembly of claim 8 , wherein the second end of the shaft is inserted in a motive device.

12. The assembly of claim 8 , wherein the shaft projects through an aperture in the flexible bag, and further including a seal for sealing the shaft to the bag.

13. The assembly of claim 12 , wherein the seal is formed by a tie surrounding the shaft.

14. A mixing tank assembly for use in mixing a fluid under sterile conditions so as to avoid contamination or leakage, comprising:

a support structure;

a flexible bag resting on the support structure, said flexible bag having an upper portion and a substantially continuous lower portion bounding a hermetically sealed compartment capable of holding the fluid under sterile conditions;

a mixer disposed within the compartment; and

a shaft having a first end for receiving the mixer.

15. The assembly of claim 14 , wherein the shaft is connected to the flexible bag.

16. The assembly of claim 14 , wherein the shaft is movable relative to the flexible bag.

17. The assembly of claim 14 , wherein the flexible bag surrounds the shaft.

18. The assembly of claim 14 , wherein the support structure comprises a generally planar surface for supporting the flexible bag.

19. The assembly of claim 14 , wherein the support structure comprises a container having a side wall with an interior surface at least partially bounding a chamber for receiving the flexible bag, said container further including a floor disposed within or at the base of the chamber, the floor having an opening extending therethrough.

20. The assembly of claim 14 , wherein the support structure includes an opening through which a second end of the shaft extends.

21. The assembly of claim 14 , wherein the flexible bag includes a nipple in the lower portion thereof and the shaft projects through the nipple.

22. The assembly of claim 21 , further including a seal for sealing the shaft to the bag.

23. The assembly of claim 22 , wherein the seal is formed by a tie surrounding the shaft.