Cyclone such as for use in a surface cleaning apparatus

1. A cyclone comprising a cyclone chamber having an air inlet, an air outlet, a first end wall, a second end wall, a longitudinal axis extending between the first and second end walls and a sidewall, the sidewall at a location of the air inlet defining a diameter of the cyclone chamber, the air inlet has an inlet end having a shape and a cross sectional area in a plane transverse to a direction of airflow through the air inlet, and the air inlet is provided at a first juncture surface of the sidewall and the first end wall, wherein the air inlet comprises a curved passage provided inside the cyclone chamber, the passage has an inlet end, an outlet end and first and second longitudinally spaced apart sections extending between the inlet and outlet ends of the curved passage, wherein the curved passage is located within the diameter of the cyclone chamber, wherein the first longitudinally spaced apart section is located further longitudinally outward from the second end wall of the cyclone chamber than the second longitudinally spaced apart section and all of an outer surface of the first end wall is located further longitudinally outward than an inner surface of the first longitudinally spaced apart sections of the passage, wherein the first juncture surface extends at an angle to both the sidewall and the first end wall and wherein the first juncture surface downstream of the air inlet approximates the shape of a portion of the air inlet that is adjacent the first juncture surface and wherein the first end wall and the first juncture surface do not extend radially outwardly beyond the sidewall, wherein the first juncture surface is rounded.

2. The cyclone of claim 1 wherein the first juncture surface has a radius that is proximate a radius of the air inlet.

3. The cyclone of claim 1 wherein the air outlet comprises a screen, wherein the screen has an inner end, the inner end has a cross sectional area in a plane transverse to a direction of airflow through the air outlet and the cross sectional area of the inner end is less than the cross sectional area of the air inlet.

4. The cyclone of claim 1 wherein the first juncture surface smoothly transitions to the sidewall without any discontinuities.

5. The cyclone of claim 1 further comprising a dirt collection chamber external to the cyclone chamber and in communication with the cyclone chamber via a dirt outlet.

6. The cyclone of claim 5 wherein the sidewall extends to the second end wall and the dirt outlet is provided in the sidewall adjacent the second end wall.

7. The cyclone of claim 1 further comprising a central insert member extending away from a center of the second end wall into the cyclone chamber and the central insert member comprises a central member wall extending away from the second end wall and the central member wall and the second end wall meet at a second juncture surface that extends at an angle to both the central member wall and the second end wall.

8. The cyclone of claim 7 wherein the second juncture surface is rounded.

9. The cyclone of claim 1 further comprising a first central insert member extending away from a center of the first end wall into the cyclone chamber and the air inlet is spaced from first central insert member.

10. The cyclone of claim 9 wherein the first central insert member comprises a vortex finder.

11. The cyclone of claim 10 wherein the first end wall is openable and at least a portion of the first juncture surface is part of the openable first end wall.

12. The cyclone of claim 9 wherein the first central insert member comprises a first central member wall extending away from the first end wall and the first central member wall and the first end wall meet at a second juncture surface that extends at an angle to both the first central member wall and the first end wall.

13. The cyclone of claim 12 wherein the second juncture surface is rounded.

14. The cyclone of claim 13 wherein the first juncture surface has a radius that is proximate a radius of the air inlet and the second juncture surface has a radius that is proximate the radius of the first juncture surface.

15. The cyclone of claim 12 further comprising a second central insert member extending away from a center of the second end wall into the cyclone chamber and the second central insert member comprises a second central member wall extending away from the second end wall and the second central member wall and the second end wall meet at a third juncture surface that extends at an angle to both the second central member wall and the second end wall.

16. The cyclone of claim 15 wherein the second and third juncture surfaces are rounded.

17. The cyclone of claim 15 wherein each of the first and second central insert members has an inner end and a screen extends between the inner ends.

18. The cyclone of claim 9 wherein the cyclone chamber has a diameter and the air inlet is spaced from the first central insert member by a distance that is up to 10% of the diameter.

19. The cyclone of claim 9 wherein a portion of the first end wall extends between the first and second juncture surfaces and the portion is flat.

20. A cyclone comprising a cyclone chamber having an air inlet, an air outlet, a first end wall, a second end wall, a longitudinal axis extending between the first and second end walls and a sidewall, the sidewall at a location of the air inlet defining a diameter of the cyclone chamber, the air inlet has an inlet end having a shape and a cross sectional area in a plane transverse to a direction of airflow through the air inlet, and the air inlet is provided at a first juncture surface of the sidewall and the first end wall, wherein the air inlet comprises a curved passage provided inside the cyclone chamber, the passage has an inlet end, an outlet end and first and second longitudinally spaced apart sections extending between the inlet and outlet ends of the passage, wherein the curved passage is located within the diameter of the cyclone chamber, wherein the first longitudinally spaced apart section extends in a plane that is transverse to the longitudinal axis, wherein the first juncture surface extends at an angle to both the sidewall and the first end wall and wherein the first juncture surface downstream of the air inlet approximates the shape of a portion of the air inlet that is adjacent the first juncture surface and wherein the first end wall and the first juncture surface do not extend radially outwardly beyond the sidewall, wherein the first juncture surface is rounded.