Surface treating appliance

1. A surface treating appliance comprising:

a first cyclonic separating unit including at least one first cyclone;

a second cyclonic separating unit located downstream from the first cyclonic separating unit and including a plurality of second cyclones arranged in parallel about an axis; and

a third cyclonic separating unit located downstream from the second cyclonic separating unit and including a plurality of third cyclones arranged in parallel about the axis;

each of the second cyclones and the third cyclones comprising a tapering body having an outside wall;

wherein the plurality of third cyclones is divided into at least a first set of third cyclones and a second set of third cyclones, each of the plurality of second cyclones and the first set of third cyclones being arranged about the second set of third cyclones;

and wherein at least a part of the outside wall of each of the plurality of second cyclones and each of the first set of third cyclones forms part of the external surface of the surface treating appliance.

2. The appliance of claim 1 , wherein the plurality of second cyclones extends about the first set of third cyclones.

3. The appliance of claim 1 , wherein the plurality of second cyclones overlaps the first set of third cyclones and the second set of third cyclones by respective different amounts.

4. The appliance of claim 1 , wherein the arrangement of the second cyclones about said axis is substantially the same as the arrangement of the first set of third cyclones about said axis.

5. The appliance of claim 1 , wherein, within each set, the third cyclones are substantially equidistant from said axis.

6. The appliance of claim 1 , wherein each third cyclone has a longitudinal axis, and wherein the longitudinal axes of the cyclones of at least the first set of third cyclones approach one another.

7. The appliance of claim 6 , wherein the longitudinal axes of the cyclones of the second set of third cyclones approach one another.

8. The appliance of claim 7 , wherein the longitudinal axes of the first set of third cyclones and the longitudinal axes of the second set of third cyclones intersect said axis.

9. The appliance of claim 8 , wherein the angle at which the longitudinal axes of the first set of third cyclones intersect said axis is different from the angle at which the longitudinal axes of the second set of third cyclones intersect said axis.

10. The appliance of claim 1 , wherein the first set of third cyclones is located above at least part of the second set of third cyclones.

11. The appliance of claim 1 , wherein the third cyclonic separating unit comprises a third set of third cyclones, and wherein the second set of third cyclones extends about at least part of the third set of third cyclones.

12. The appliance of claim 11 , wherein the second set of third cyclones is located above at least part of the third set of third cyclones.

13. The appliance of claim 1 , wherein each set of third cyclones comprises a respective different number of cyclones.

14. The appliance of claim 1 , wherein the number of third cyclones is greater than the number of second cyclones.

15. The appliance of claim 1 , wherein the second cyclonic separating unit and the first set of third cyclones comprise the same number of cyclones.

16. The appliance of claim 1 , wherein each second cyclone has a longitudinal axis, and wherein the longitudinal axes of the second cyclones approach one another.

17. The appliance of claim 16 , wherein the longitudinal axes of the second cyclones intersect said axis.

18. The appliance of claim 1 , wherein the plurality of second cyclones and the first set of third cyclones are equidistant from said axis.

19. The appliance of claim 1 , comprising a first dust collector for receiving dust from the first cyclonic separating unit, a second dust collector for receiving dust from the second cyclonic separating unit, and a third dust collector for receiving dust from the third cyclonic separating unit.

20. The appliance of claim 1 , comprising a vacuum cleaning appliance.