In general, a dust collecting apparatus of a vacuum cleaner can be classified as either a dust collecting apparatus which uses a filter or a cyclone dust collecting apparatus which separates dust from the air by centrifugal force. The term “dust” is used herein to refer collectively to dust, dirt, particulates, debris, and other similar matter that can be entrained with the air suctioned by the vacuum cleaner. The cyclone dust collecting apparatus can be further classified into a single cyclone dust collecting apparatus which separates the dust by using a single cyclone or a multi-cyclone dust collecting apparatus which separates the dust in two steps by using more than one cyclone.
Conventional cyclone dust collecting apparatuses are disclosed in Korean Patent Nos. 645375 and 437156 to the present applicant and International Patent Publication No. WO 02/067750 to Dyson. The cyclone dust collecting apparatus disclosed in Korean Patent No. 645375 includes a first cyclone and a plurality of second cyclones disposed adjacent to an outer circumferential surface of the first cyclone. The dust collecting apparatus has a reduced height but a relatively larger outer diameter due to the cyclones disposed adjacent to the outer circumferential surface of the first cyclone.
The cyclone dust collecting apparatus disclosed in Korean Patent No. 437156 has a second cyclone that is disposed in a first cyclone and has a reduced outer diameter. However, because the air to the second cyclone is drawn in through a single air inlet, a whirling force of the second cyclone is weakened. In addition, to dump the collected dust, a user has to move the entire dust collecting apparatus to a trash can. Also, because the first and the second cyclone are neither separated nor subdivided into respective components, cleaning the inner parts of the dust collecting apparatus, maintaining the dust collecting apparatus, and repairing the dust collecting apparatus is difficult.
The cyclone dust collecting apparatus disclosed in International Patent Publication No. WO 02/067750 has a height that prevents it from being applied to a canister vacuum cleaner. In addition, to dump the collected dust, the user has to move the entire the dust collecting apparatus to a trash can.