Delivery devices

1. A delivery device comprising:

a container containing a dose of a powder and having at least one exit orifice for dispensing the dose from the container;

a chamber adapted to receive the container in an operative configuration;

at least one gas inlet by which gas may enter the chamber and at least one gas outlet by which gas and entrained powder may exit the chamber, wherein the delivery device is operable to generate a gas flow through the chamber between the at least one gas inlet and the at least one gas outlet, which brings about orbital motion of the container within the chamber in that at least a central region of the container orbits a central axis of the chamber, wherein a volume occupied by the container is at least 50% of a volume of the chamber, and a diameter of the container is greater than a height of the container.

2. The delivery device as claimed in claim 1 , wherein the volume of the container is between 50% and 72% of the volume of the chamber.

3. The delivery device as claimed in claim 1 , wherein the volume of the container is between 55% and 65% of the volume of the chamber.

4. The delivery device as claimed in claim 1 , wherein a diameter of the container is at least 50% of a diameter of the chamber.

5. The delivery device as claimed in claim 1 , wherein a diameter of the container is at least 60% of a diameter of the chamber.

6. The delivery device as claimed in claim 1 , wherein a diameter of the container is between 70% and 85% of a diameter of the chamber, or between 75% and 80%, of the diameter of the chamber.

7. The delivery device as claimed in claim 1 , wherein all parts of the container undergo orbital motion.

8. The delivery device as claimed in claim 1 , wherein the container also undergoes rotational motion, in which the container rotates about its own central axis.

9. The delivery device as claimed in claim 8 , wherein the rotational motion of the container occurs concurrently with orbital motion, with the container rotating in rolling contact with a circumferential wall of the chamber in an epicyclic fashion as at least a central region of the container orbits the central axis of the chamber.

10. The delivery device as claimed in claim 8 , wherein the at least one exit orifice is positioned on a surface of the container that faces outwardly relative to the axis of orbital motion or the axis of rotational motion of the container, during use.

11. The delivery device as claimed in claim 8 , wherein the at least one exit orifice is positioned on a part of the container that is furthermost from the axis of orbital motion or the axis of rotational motion of the container, during use.

12. The delivery device as claimed in claim 1 , wherein an orientation of the container remains constant relative to the central axis of the chamber during orbital motion.

13. The delivery device as claimed in claim 1 , wherein the container is cylindrical.

14. The delivery device as claimed in claim 13 , wherein the at least one exit orifice is located on a circumferential wall of the container.

15. The delivery device as claimed in claim 13 , wherein the at least one orifice is a plurality of exit orifices that are disposed around the circumference of the container at equiangularly spaced positions.

16. The delivery device as claimed in claim 1 , wherein the container is formed of a number of cooperating components, wherein the at least one exit orifice is defined between the cooperating components.

17. The delivery device as claimed in claim 1 , wherein the at least one exit orifice is integrally formed in the container.

18. The delivery device as claimed in claim 1 , wherein the at least one exit orifice is preformed, and closed by a closure member before the container is brought into an operative configuration.

19. The delivery device as claimed in claim 1 , wherein a size of the at least one exit orifice has been selected to provide a pre-determined rate of powder emission from the container.

20. The delivery device as claimed in claim 1 , wherein the at least one exit orifice has a combined cross-sectional area of less than 1 mm 2 .

21. The delivery device as claimed in claim 1 , wherein the at least one exit orifice has a combined cross-sectional area of less than 0.5 mm 2 .

22. The delivery device as claimed in claim 1 , wherein the at least one exit orifice has a combined cross-sectional area of less than 0.3 mm 2 .

23. The delivery device as claimed in claim 1 , wherein the chamber is cylindrical, and has a diameter greater than a height.

24. The delivery device as claimed in claim 23 , wherein the at least one gas inlet is arranged such that gas enters the chamber tangentially.

25. The delivery device as claimed in claim 23 , wherein the at least one gas inlet is a plurality of gas inlets, opening into the chamber at equiangularly spaced positions.

26. The delivery device as claimed in claim 1 , wherein the at least one gas outlet comprises a mesh or a grid formed in part of a chamber wall.

27. The delivery device as claimed in claim 26 , wherein the mesh or the grid lies in a plane which is parallel to a plane of orbital motion of the container.

28. A method of treatment of a patient with a respiratory disorder, comprising administering at least one powdered medicament using the delivery device as claimed in claim 1 .

29. The delivery device as claimed in claim 1 , wherein the gas flow between the at least one gas inlet and the at least one gas outlet is generated by a patient inhaling through the delivery device.

30. The delivery device as claimed in claim 1 , wherein a minimum clearance between an end wall of the chamber and the container is less than 15% of the height of the chamber.