Vacuum cleaner

1. A vacuum cleaner comprising:

an air inlet opening located in the bottom of a first chamber,

an air outlet opening located in the wall of a second chamber, wherein a dividing wall separates the first and second chambers,

a rotatable separator located at the top of the first chamber configured for separating air and airborne particles, which separator comprises at least one air entrance opening located between the air inlet opening and the air outlet opening,

air-guide means located beneath the separator configured for guiding at least part of the air towards the separator, and further configured for shielding the rotatable separator from said airborne particles,

a vacuum fan located in the second chamber arranged between the separator in the first chamber and the air outlet opening located in the wall of the second chamber,

wherein the vacuum fan has a larger diameter than the separator, wherein the separator comprises a fan,

wherein the rotatable separator is arranged in the second chamber between the dividing wall separating the first and second chambers and the air-guide means,

wherein said air-guide means provides in use an at least partially closed boundary in axial direction for a column of rotating air around the separator,

wherein a minimum distance (R ag ) of an edge of the air-guide means to the rotating axis of the separator is larger than a distance (R s ) of the air entrance opening of the separator to the rotating axis of the separator.

2. A vacuum cleaner according to claim 1 , wherein the air-guide means is non-rotatable or is rotatable with respect to the separator at an angular velocity between null and a value lower than the angular velocity of the separator.

3. A vacuum cleaner according to claim 1 , wherein the column of rotating air around the separator has a maximum dimension (H) in an axial direction, wherein the separator is rotatable during use at a maximum angular velocity (ω) at which a maximum angular velocity (ω) air is flowing between the air inlet opening and the air outlet opening at a maximum flow rate (Q) in an unloaded condition, wherein the minimum distance (R ag ) of an edge of the air-guide means to the rotating axis of the separator satisfies the following relation:

R

ag

⁢

≥

R

s

*

(

1

+

(

Q

2

*

π

*

R

ag

⁢

2

*

H

*

ω

)

)

.

4. A vacuum cleaner according to claim 1 , wherein a smallest distance (H s-ag ) in an axial direction of the axis between the separator and the air-guide means is such that in use less than 5%, more preferably 1% and even more preferably less than 0, 1% of the particles picked up by the vacuum cleaner and having a size of at least 100 μm (micron) enter the separator.

5. A vacuum cleaner according to claim 1 , wherein the air-guide means is located at a fixed distance (H s-ag ) from the separator.

6. A vacuum cleaner according to claim 1 , wherein the air-guide means is movable towards and away from the separator such that a smallest distance (H s-ag ) in an axial direction of the axis between the separator and the air-guide means is variable.

7. A vacuum cleaner according to claim 6 , wherein the vacuum cleaner is provided with a chamber to be filled with liquid, whereby the air-guide means is floatable on the liquid.

8. A vacuum cleaner according to claim 1 , wherein the air-guide means have a rounded shape, the axis of which coincides with a rotating axis of the separator.

9. A vacuum cleaner according to claim 1 , wherein the fan and vacuum fan are rotatable together about a rotating axis.

10. A vacuum cleaner according to claim 1 , wherein the air-guide means defines a dust separation space for creating the column of rotating air around the separator and a particle collecting space of the chamber, for collecting particles separated from the air to prevent re-introduction of such particles into the column of rotating air.