Fan

1. A bladeless fan assembly for creating an air current, the fan assembly comprising:

a nozzle, and

a device creating an air flow through the nozzle, the nozzle comprising an interior passage, formed between a first wall and a second wall, wherein a distal end of the first wall overlaps a distal end of the second wall to form, near the distal ends of the first and second walls,

a mouth for receiving the air flow from the interior passage,

a tapered region, located downstream from the mouth, and

an outlet, located downstream of the tapered region, for releasing the air flow from the nozzle, wherein a distance between the first wall and the second wall is greater at the mouth than at the outlet, and

a Coanda surface located adjacent the outlet,

wherein the first wall is curved proximate to its distal end to direct the air flow over the Coanda surface, and

wherein a thickness of the first wall decreases near the distal end, and a thickness of the second wall increases near the distal end.

2. The fan assembly as claimed in claim 1 , wherein the nozzle defines an opening through which air from outside the fan assembly is drawn by the air flow directed over the Coanda surface.

3. The fan assembly as claimed in claim 1 or 2 , wherein the nozzle comprises a loop.

4. The fan assembly as claimed in claim 1 or 2 , wherein the nozzle is annular.

5. The fan assembly as claimed in claim 1 or 2 , wherein the nozzle is at least partially circular.

6. The fan assembly as claimed in claim 1 or 2 , wherein the interior passage is continuous.

7. The fan assembly as claimed in claim 1 or 2 , wherein the interior passage is annular.

8. The fan assembly as claimed in claim 1 or 2 , wherein the mouth is annular.

9. The fan assembly as claimed in claim 1 or 2 , wherein the mouth is concentric with the interior passage.

10. The fan assembly as claimed in claim 1 or 2 , wherein the nozzle comprises a diffuser located downstream of the Coanda surface.

11. The fan assembly as claimed in claim 1 or 2 , wherein a spacing between the first and second walls at the mouth is in a range from 1 mm to 5 mm.

12. The fan assembly as claimed in claim 1 or 2 , wherein the Coanda surface extends symmetrically about an axis.

13. The fan assembly as claimed in claim 12 , wherein an angle subtended between the Coanda surface and the axis is in a range from 7° to 20°.

14. The fan assembly as claimed in claim 12 , wherein the nozzle extends by a distance of at least 5 cm in the direction of the axis.

15. The fan assembly as claimed in claim 12 , wherein the nozzle extends about the axis by a distance in a range from 30 cm to 180 cm.

16. The fan assembly as claimed in claim 12 , wherein an angle subtended between the Coanda surface and the axis is 15°.

17. The fan assembly as claimed in claim 1 or 2 , wherein the device creating the air flow through the nozzle comprises an impeller driven by a motor.

18. The fan assembly as claimed in claim 17 , wherein the device creating the air flow comprises a DC brushless motor and a mixed flow impeller.