Household appliance having an improved cyclone and a cyclone for same
A cyclone for a hand vacuum cleaner has an outlet port that is sized to produce an annular flow band in the cyclone which extends radially inwardly to overlap the solid sidewall of the vortex finder.
1. A surface cleaning apparatus comprising:
(a) an air flow path from a dirty air inlet to a clean air outlet with a cyclone and a motor and fan assembly provided in the air flow path,
(b) the cyclone comprising a cyclone axis of rotation centrally positioned in the cyclone and extending between an inlet end of the cyclone and an axially opposed outlet end of the cyclone, a cyclone sidewall extends between the inlet end and the axially opposed outlet end, the inlet end having a cyclone air inlet, the axially opposed outlet end comprising an outlet end wall and a vortex finder extending inwardly into the cyclone,
(c) the vortex finder comprising a conduit portion extending inwardly into the cyclone and a screen portion, the conduit portion having an inlet end and an outlet end, and the screen portion extending inwardly into the cyclone from the inlet end of the conduit portion, the conduit portion has a radial width with a radial inner surface and a radial outer surface at the outlet end of the conduit portion, wherein, in a plane that is transverse to the cyclone axis of rotation and that extends through the conduit portion, the radial outer surface is located a first radial width from an inner surface of the cyclone sidewall and the radial inner surface is located a second radial width from the inner surface of the cyclone sidewall, and,
(d) the cyclone air inlet has an outlet port having a width in a direction transverse to a direction of flow through the outlet port, wherein the width has a dimension that is between the first radial width and the second radial width, and wherein the outlet port has an outlet port cross-sectional flow area in the direction transverse to the direction of flow through the outlet port, and wherein the outlet port cross-sectional flow area is the same as or larger than a cross-sectional area of the conduit portion in the plane.
2. The surface cleaning apparatus of claim 1 wherein the cyclone has a diameter of up to 100 mm.
3. The surface cleaning apparatus of claim 2 wherein the vortex finder has a diameter of 25 mm to 40 mm.
4. The surface cleaning apparatus of claim 1 wherein the cyclone has a diameter of up to 80 mm and the conduit portion of the vortex finder has a diameter of up to 40 mm.
5. The surface cleaning apparatus of claim 1 wherein the conduit portion is tapered.
6. The surface cleaning apparatus of claim 5 wherein the conduit portion is tapered at an angle of up to 25°.
7. The surface cleaning apparatus of claim 5 wherein the conduit portion is tapered at an angle of 2°-15°.
8. The surface cleaning apparatus of claim 1 wherein the screen is tapered at an angle of up to 25°.
9. The surface cleaning apparatus of claim 1 wherein the cyclone air inlet is an axial air inlet, wherein the outlet port is provided in an inlet end wall of the cyclone.
10. The surface cleaning apparatus of claim 1 wherein the cyclone air inlet is a tangential air inlet wherein the outlet port is provided in the cyclone sidewall.
11. The surface cleaning apparatus of claim 1 wherein the cyclone has an air flow energy utilization for air flow through the cyclone of 1 CFM or more per 1 Watt.
12. The surface cleaning apparatus of claim 11 wherein the cyclone has a diameter of up to 100 mm.
13. The surface cleaning apparatus of claim 11 wherein the vortex finder has a diameter of 25 mm to 40 mm.
14. The surface cleaning apparatus of claim 11 wherein the cyclone has a diameter of up to 80 mm and the conduit portion of the vortex finder has a diameter of up to 40 mm.
15. The surface cleaning apparatus of claim 14 wherein the air flow energy utilization is 1.1 CFM per 1 Watt or more.
16. The surface cleaning apparatus of claim 14 wherein the air flow energy utilization is 1.25 CFM per 1 Watt or more.
17. The surface cleaning apparatus of claim 1 wherein the screen is tapered at an angle of 2°-15°.