Patent Publication Number: US-7708791-B2

Title: Cyclone dust separating apparatus

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   This application is a divisional application of U.S. application Ser. No. 11/386,476, filed on Mar. 22, 2006, now U.S. Pat. No. 7,594,943, which claims the benefit of U.S. Provisional Applications No. 60/666,143 filed Mar. 29, 2005 and No. 60/698,387 filed on Jul. 12, 2005 in the United States Patent and Trademark Office and claims the benefit of Korean Patent Applications No. 2005-37406 filed on May 4, 2005 and No. 2005-71976 filed on Aug. 5, 2005 in the Korean Intellectual Property Office, the entire disclosures of all of which are incorporated herein by reference. 

   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to a vacuum cleaner. More particularly, the present invention relates to a cyclone dust separating apparatus mounted in a vacuum cleaner to separate dust from air drawn in from a surface being cleaned. 
   2. Description of the Related Art 
   In general cyclone dust separating apparatuses, impurities (hereinafter, referred to as ‘dust’) are separated from external drawn-in air using a centrifugal force, and the separated dust is collected in a dust collection chamber. Having advantages in lifespan and hygiene in comparison with a conventionally-used dust bag, the cyclone dust separating apparatus has been widely used in a vacuum cleaner nowadays. 
   A conventional cyclone dust separating apparatus comprises a cyclone chamber having a tubular shape so that drawn-in air rotates therein, an air inlet, and an air outlet. The air inlet is connected tangentially to an upper sidewall of the cyclone chamber for smooth rotation of the air. The air outlet is disposed at an upper end of the cyclone chamber so that the air descending in a rotating manner and ascending back in the cyclone chamber is guided to the outside of the cyclone dust separating apparatus. However, in the conventional cyclone dust separating apparatus having the above structure, the descending rotary air and the ascending air unavoidably collides with each other in the cyclone chamber because both the air inlet and the air outlet are disposed at the upper part of the cyclone chamber, thereby deteriorating dust separating efficiency of the cyclone dust separating apparatus. 
   In order to overcome such deterioration of the dust separating efficiency, a multi-cyclone dust separating apparatus has been developed and practically used in a vacuum cleaner. The multi-cyclone dust separating apparatus has a first cyclone chamber for separating relatively larger dust and a plurality of second cyclone chambers for separating relatively smaller dust. In general multi-cyclone dust separating apparatus, the first cyclone chamber is disposed in the center while the second cyclone chambers are annularly arranged around the first cyclone chamber. 
   However, because the air inlet and the air outlet of the first cyclone chamber are both disposed at the upper part thereof in the conventional multi-cyclone dust separating apparatus, arrangement of the second chambers is restricted because the second cyclone chambers should not interfere with the air inlet. 
   SUMMARY OF THE INVENTION 
   An aspect of the present invention is to solve at least the above problems and/or disadvantages and to provide at least the advantages described below. Accordingly, an aspect of the present invention is to provide a cyclone dust separating apparatus capable of improving cleaning efficiency by reducing loss of a suction force. 
   Another aspect of the present invention is to provide a cyclone dust separating apparatus capable of improving flexibility in design. 
   In order to achieve the above-described aspects of the present invention, there is provided a cyclone dust separating apparatus for separating dust from external air drawn in thereto and discharging the separated dust. The cyclone dust separating apparatus includes at least one first cyclone body having a tubular shape and forming a first cyclone chamber where the external air is rotated; and at least one second cyclone body forming a second cyclone chamber where the air discharged from the first cyclone chamber is rotated again to separate dust, wherein the external air is drawn in through a lower end of the first cyclone chamber and discharged through an upper end of the first cyclone chamber, and the air discharged from the first cyclone chamber is drawn in through an upper end of the second cyclone chamber and discharged through an upper end of the second cyclone chamber. 
   Preferably, a plurality of the second cyclone bodies are annularly arranged around the first cyclone chamber. 
   According to an embodiment of the present invention, the cyclone dust separating apparatus may further comprise a first inlet penetrating a lower end of the first cyclone body to draw the air into the first cyclone chamber. 
   The cyclone dust separating apparatus further comprises a discharge pipe extended from the upper end of the first cyclone chamber toward the lower end of the first cyclone chamber to be partially inserted in the first cyclone chamber and having a first outlet for discharging the air cleaned by the first cyclone chamber; a first dust discharge port formed at an upper part of an outer circumference thereof to discharge the dust separated by the first cyclone chamber; and a first dust collection chamber collecting the dust discharged through the first dust discharge port, 
   The cyclone dust separating apparatus further comprises a first connection path guiding the air discharged through the first outlet branchingly to second inlets formed at the upper ends of the respective second cyclone chambers; a second dust discharge port formed at the lower ends of the respective second cyclone chambers; a second dust collection chamber collecting the dust discharged through the respective second dust discharge ports; and a second connection path having a second outlet at an end thereof to guide the air being discharged from the respective second cyclone chambers. 
   The cyclone dust separating apparatus further comprises a third outlet connected to the other end of the second connection path to collectively discharging the air being discharged through the second outlet. 
   The cyclone dust separating apparatus further comprises a cyclone main body having a tubular shape enclosing the first cyclone body and the second cyclone body, wherein the cyclone main body comprises a tubular inner wall surrounding the first cyclone body at a predetermined distance from the first cyclone body, and a tubular outer wall surrounding the inner wall at a predetermined distance from the inner wall, the first dust collection chamber is disposed between the first cyclone chamber and the inner wall while the second dust collection chamber between the inner wall and the outer wall. 
   The respective second cyclone chambers are formed as an inverse cone having a diameter reducing from an upper end to a lower end, and are tilted so that part of a sidewall of each second cyclone body, facing an outer wall of the cyclone main body, is disposed parallel with the outer wall of the cyclone main body. 
   The cyclone dust separating apparatus may further comprise a cover member mounted at the upper end and having second cyclone mounting holes corresponding to the upper ends of the second cyclone bodies for mounting of the plurality of second cyclone bodies in the cyclone main body. 
   According to second embodiment of the present invention, the cyclone dust separating apparatus further comprises a bottom surface constituting a bottom of the first cyclone body; and a first inlet penetratingly formed at the bottom surface to guide the air drawn in from the outside into the first cyclone chamber. 
   The cyclone dust separating apparatus further comprises a ceiling having the first outlet that guides the air discharged from the first cyclone chamber and mounted at an upper part of the first cyclone body; a guide member formed in the first cyclone chamber to cover an upper part of the first inlet and partially spirally formed so that the external air drawn in through the first inlet is rotated and guided upward to the first outlet; a first dust discharge port formed at an upper part of an outer circumference of the first cyclone chamber disposed in the vicinity of the ceiling; and a first dust collection chamber collecting the dust discharged through the first dust discharge port. 
   The ceiling comprises a discharge pipe extended from the ceiling toward the bottom surface of the first cyclone chamber and having the first outlet at the lower end thereof, and the first outlet is disposed lower than the first dust discharge port. 
   The discharge pipe has a skirtlike form expanding as going distanced from the first cyclone chamber so that rotational radius of the air ascending and rotating in the first cyclone chamber increases as going toward the upper end of the first cyclone chamber. 
   The bottom surface has a suction duct protruded downward in a corresponding form to the first inlet, and the suction duct is inserted in a mounting opening which is formed at a bottom of a dust collecting chamber of a vacuum cleaner in a corresponding form to the suction duct to removably mount the first cyclone body. 
   A grill member is removably mounted to the first outlet. 
   The cyclone dust separating apparatus may further comprise a first connection path guiding the air discharged through the first outlet branchingly to second inlets formed at the upper ends of the respective second cyclone chambers; a second dust discharge port formed at the lower ends of the respective second cyclone chambers; a second dust collection chamber collecting the dust discharged through the respective second dust discharge ports; and a second connection path having a second outlet at an end thereof to guide the air being discharged from the respective second cyclone chambers. 
   The cyclone dust separating apparatus may further comprise a cyclone main body enclosing the first and the second cyclone bodies and mounted with the upper ends, which are opened, of the first cyclone chamber and the second cyclone chambers; an intermediate cover comprising a first connection path of which an inlet is connected to the first outlet and an outlet connected to the second inlet and a second connection path formed as a pipe, and covering the opened upper end of the cyclone main body; and an upper cover having the third outlet collectively discharging the air discharged from the second outlet to the outside and covering an upper part of the intermediate cover. 
   The cyclone main body comprises a tubular inner wall surrounding the first cyclone body at a predetermined distance from the first cyclone body, and a tubular outer wall surrounding the inner wall at a predetermined distance from the inner wall and connected to the intermediate cover by the upper end thereof, the first dust collection chamber is disposed between the first cyclone chamber and the inner wall while the second dust collection chamber between the inner wall and the outer wall. 
   The respective second cyclone chambers are formed as an inverse cone having a diameter reducing from an upper end to a lower end, and are tilted so that part of a sidewall of each second cyclone body, facing an outer wall of the cyclone main body, is disposed parallel with the outer wall of the cyclone main body. 
   Preferably, an interval between the inner wall and the outer wall is substantially equal to a diameter of the second dust discharge port. 
   The cyclone main body further comprises a lower cover removably mounted to a lower end of the outer wall to cover the opened lower ends of the first cyclone chamber, the inner wall, and the outer wall. 
   In addition, a filter member is removably mounted between the upper cover and the intermediate cover to further filter the air moving to the third outlet. 

   
     BRIEF DESCRIPTION OF THE DRAWING FIGURES 
     The above aspect and other features of the present invention will become more apparent by describing in detail exemplary embodiments thereof with reference to the attached drawing figures, wherein; 
       FIG. 1  is a perspective view schematically showing a cyclone dust separating apparatus according to a first embodiment of the present invention; 
       FIG. 2  is an exploded perspective view of the cyclone dust separating apparatus of  FIG. 1 ; 
       FIG. 3  is a sectional view of  FIG. 1  cut along a line III-III; 
       FIG. 4  is an exploded perspective view schematically showing a vacuum cleaner applying the cyclone dust separating apparatus according to the first embodiment of the present invention; 
       FIG. 5  is an exploded perspective view schematically showing a vacuum cleaner applying the cyclone dust separating apparatus according to a second embodiment of the present invention; 
       FIG. 6  is an exploded perspective view of the cyclone dust separating apparatus of  FIG. 5 ; and 
       FIG. 7  is a sectional view of  FIG. 5 , for showing the operation of the cyclone dust separating apparatus. 
   

   DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS 
   Hereinafter, certain embodiments of the present invention will be described in detail with reference to the accompanying drawing figures. 
   In the following description, same drawing reference numerals are used for the same elements even in different drawings. The matters defined in the description such as a detailed construction and elements are nothing but the ones provided to assist in a comprehensive understanding of the invention. Thus, it is apparent that the present invention can be carried out without those defined matters. Also, well-known functions or constructions are not described in detail since they would obscure the invention in unnecessary detail. 
   Referring to  FIGS. 1 through 4 , a cyclone dust separating apparatus  100  according to an embodiment of the present invention comprises a first cyclone body  120  defining a first cyclone chamber  121  for primarily separating relatively larger dust from dust-laden airdrawn in through a first inlet  122 , a cover member  130 , and a second cyclone body  140  defining a second cyclone chamber  142  for secondarily separating relatively smaller dust from the air primarily cleaned by the first cyclone chamber  121 . The cyclone dust separating apparatus  100  includes a cyclone main body  110 , which encloses the first and the second cyclone bodies  120  and  140 . 
   The first cyclone body  120  has a cylindrical shape so that the first cyclone chamber  121  can effectively induce rotation of the air drawn in through the first inlet  122 . The first inlet  122  is disposed at a lower end of the first cyclone chamber  121  and fluidly communicates with a suction port  103  ( FIG. 4 ) of the bottom surface brush  101  ( FIG. 4 ). Since the first inlet  122  is formed in a tangential direction with respect to the first cyclone chamber  121 , the air drawn in through the first inlet  122  is rotated in the first cyclone chamber  121 . A first dust discharge port  123  is annularly formed at an upper end of the first cyclone chamber  121 . The dust is raised along a first wall  126  of the first cyclone chamber  121  by a centrifugal force of the air rotating in the cyclone chamber  121  and then is discharged through the first discharge port  123  into a first dust collection chamber  124 . 
   A discharge pipe  128  is disposed at the upper end of the first cyclone chamber  121 . A lower end of the discharge pipe  128  is partly inserted in the first cyclone chamber  121 . A first outlet  125  is formed at a lower end of the discharge pipe  128  for discharging the air primarily cleaned by the first cyclone chamber  121 . The discharge pipe  128  has an enough length so that the first outlet  125  is disposed lower than the first discharge port  123 . Because the first inlet  122  is disposed at the lower end of the first cyclone chamber  121 , and the first outlet  125  at the upper end of the first cyclone chamber  121 , the air drawn in through the first inlet  122  ascends in a rotating manner and escapes through the first outlet  125 . Therefore, collision between the air current being drawn in and the air current being discharged in the first cyclone chamber  121  can be prevented, consequently improving the cleaning efficiency. 
   The first dust collection chamber  124  is formed between the first wall  126  and a second wall  112  of the first cyclone body  120  to collect the dust discharged through the first discharge port  123 . A second dust collection chamber  145  is annularly formed to surround the first dust collection chamber  124  to collect the relatively smaller dust separated from the second cyclone chamber  142 . The cyclone main body  110  comprises the second wall  112  cylindrically formed to surround the first cyclone body  120  at a predetermined distance from the first wall  126  of the first cyclone body  120 , and a third wall  113  cylindrically formed to surround the second wall  112  at a predetermined distance from the second wall. Here, the first dust collection chamber  124  is disposed between the first wall  126  of the first cyclone body  120  and the second wall  112 , and the second dust collection chamber  145  is disposed between the second wall  112  and the third wall  113 . 
   The cover member  130  has a center hole  131  for inserting therein the discharge pipe  128 . A plurality of second cyclone mounting holes  132  are arranged annularly around the cover member  130  to support an upper part of the second cyclone bodies  140  through upper ends of the second cyclone bodies  140 . The cover member  130  simply helps connect the second cyclone bodies  140  within the cyclone main body  110 . Therefore, the cover member  130  may be omitted according to design. 
   According to an embodiment of the present invention, a plurality of the second cyclone bodies  140  are annularly arranged around the first cyclone body  120 . A first connection path  141  guides the air primarily cleaned by the first cyclone chamber  121  to the second cyclone chamber  142 . The first connection path  141  is connected to the first outlet  125  of the discharge pipe  128  by one end and connected to a second inlet  143  formed at the upper end of each second cyclone chamber  142  by the other end. Since the second inlet  143  is connected to the second cyclone chamber  142  in a tangential direction, the air drawn in through the second inlet  143  can form a rotary air current in the second cyclone chamber  142 . For fluid communication between the first cyclone chamber  121  and the plurality of second cyclone chambers  142 , the first connection path  141  is provided in the corresponding number to the second cyclone chambers  142 . Therefore, the plurality of first connection paths  141  are formed in a manner of branching off from the first outlet  125 . The respective first connection paths  141  are partially spirally formed so as to generate the rotary air current in the second cyclone chambers  142 . 
   A second dust discharge port  144  is disposed at a lower end of the second cyclone body  140  having an inverse conical shape. The dust separated in the second cyclone chamber  142  is discharged through the second dust discharge port  144  to the second dust collection chamber  145 . A second connection path  161  guides the air being cleaned in the respective second cyclone chambers  142  and discharged. The respective second connection paths  161  have a second outlet  146  at one end and are connected to a third outlet  162  by the other end. The second connection path  161  is provided corresponding to the second outlet  146  in number and converged into the third outlet  162 . The third outlet  162  is a path for discharging the air being discharged through the plurality of second connection paths  161 , finally from the cyclone dust separating apparatus  100 . To this end, the third outlet  162  is fluidly communicated with a driving source  102  ( FIG. 4 ) that generates a suction force. 
   The second cyclone bodies  140  are shaped as an inverse cone having a diameter reducing from an upper end to a lower end. Also, the second cyclone bodies  140  are annularly arranged around the first cyclone body  120  at regular intervals. The second cyclone bodies  140  are inserted in the second dust collection chamber  145  so as to be arranged parallel with the first cyclone body  120 . By thus arranging the first and the second cyclone bodies  120  and  140  in parallel, height of the cyclone dust separating apparatus  100  can be reduced. In addition, by disposing the first inlet  122  at the lower end of the first cyclone chamber  121 , the number and the arrangement of the second cyclone bodies  140  are not restricted. Therefore, dust separating efficiency can be improved by increasing the number of the second cyclone bodies  140 . 
   The respective second cyclone bodies  140  are defined so that a part  147  of a sidewall of each second cyclone body  140 , facing the outer wall  113  of the cyclone main body  110 , is disposed parallel with the third wall  113  of the cyclone main body  110 . In addition, the respective second cyclone bodies  140  are defined so that a part  148  of the sidewall of each second cyclone body  140 , facing the second wall  112 , is disposed at an angle with the second wall  112 . Because, generally, the first cyclone chamber  121  separates most of the dust and relatively larger dust, it is preferred that the first dust collection chamber  124  has as large volume as possible. According to an embodiment of the present invention, volume of the second dust collection chamber  145  is decreased while volume of the first dust collection chamber  124  is increased. 
   Hereinafter, the operation of the cyclone dust separating apparatus  100  according to an embodiment of the present invention will be described in greater detail with reference to  FIG. 3 . 
   As the suction force is generated by the driving source  102  ( FIG. 4 ), dust-laden air is drawn in through the suction port  103  ( FIG. 4 ) of the bottom surface brush  101 . The dust-laden air is drawn into the first cyclone chamber  121  through the first inlet  122  and ascends in a rotating manner. Here, the dust is rotated and raised along the first wall  126  of the first cyclone body  120  by the centrifugal fore of the rotary air current. The dust raised by the ascending air current is discharged through the first dust discharge port  123  and collected in the first dust collection chamber  124 . The cleaned air is discharged through the first outlet  125 . As described above, the air drawn in through the first inlet  122  reaches the first outlet  146  by generating the air current in one direction, thereby preventing collision between air currents moving in opposite directions. As a result, loss of the suction force decreases, and the cleaning efficiency improves. 
   The air discharged through the first outlet  125  is drawn into the second cyclone chambers  142  through the first connection path  141  and the second inlet  143 . The drawn-in air descends as it rotates in the second cyclone chamber  142 . During this, the dust descends along the parts  147 ,  148  of the sidewall of the second cyclone body  140 , being entrained in the descending air current. Then, the dust is discharged through the second dust discharge port  144  and collected in the second dust collection chamber  145 . The air cleaned by the second cyclone chamber  142  is raised back to be discharged through the second outlet  146  and the second connection path  161 . 
     FIG. 4  is an exploded perspective view of a vacuum cleaner adopting the cyclone dust separating apparatus  100  according to a first embodiment of the present invention. Referring to  FIG. 4 , the vacuum cleaner according to an embodiment of the present invention comprises the bottom surface brush  101  having the suction port  103 , a cleaner body  104  having the driving source  102 , a suction path  105  and a discharge path  106 , and the cyclone dust separating apparatus  100  removably mounted to a mounting portion  107  of the cleaner body  104 . 
   The driving source  102  is disposed at a lower part of the cleaner body  104  and may comprise a suction motor for generating the suction force. The suction brush  101  includes the suction port  103  to draw in the dust from a surface being cleaned using the suction force generated by the driving source  102 . The suction path  105  is disposed in the cleaner body  104  in fluid communication with the suction port  103  and connected to the first inlet  122  of the cyclone dust separating apparatus  100  by one end thereof. The discharge path  106  is formed at the cleaner body  104 . One end of the discharge path  106  is connected to the driving source  102  while the other end is extended to the mounting portion  107  and connected to the third outlet  162  of the cyclone dust separating apparatus  100 , as shown in  FIG. 4 . 
   The suction force generated by the driving source  102  mounted in the above-structured is sequentially passed through the discharge path  105 , the cyclone dust separating apparatus  100  and the suction path  106  and finally transmitted to the suction port  103 . The dust on the surface being cleaned is drawn in through the suction port  103  by the suction force. The drawn-in dust is passed through the suction path  105 , the cyclone dust separating apparatus  100 , the discharge path  106  and the driving source  102  in reverse order and then discharged to the outside. Although an upright vacuum cleaner has been illustrated by way of example, it will be sure understood by those skilled in the art that the cyclone dust separating apparatus of the present invention can be applied to other types of vacuum cleaner, such as a canister vacuum cleaner and a handy vacuum cleaner. 
     FIGS. 5 through 7  show a cyclone dust separating apparatus according to a second embodiment of the present invention, and a vacuum cleaner comprising the cyclone dust separating apparatus. With reference to the drawings, the cyclone dust separating apparatus according to the second embodiment of the present invention will now be described in detail. 
   Referring to  FIG. 5 , a vacuum cleaner  300  having a cyclone dust separating apparatus  200  of the present embodiment comprises a suction assembly  350  for drawing in the dust on the surface being cleaned, and a cleaner body  310  including therein a suction motor  360  for generating the suction force to draw in the dust. The cleaner body  310  comprises a suction path  311  connected to the suction assembly  350 , a discharge path  315  connected to the outside of the cleaner body  320 , and a dust collecting chamber  320  disposed between the suction path  111  and the discharge path  315  and mounting the cyclone dust separating apparatus  200 . 
   Referring to  FIGS. 5 to 7 , the cyclone dust separating apparatus  200  according to the second embodiment of the present invention comprises a plurality of cyclone chambers. To this end, the cyclone dust separating apparatus  200  comprises a cyclone main body  210 , an intermediate cover  270  connected to an upper end of the cyclone main body  210 , and an upper cover  250  connected to an upper end of the intermediate cover  270 . The cyclone main body  210 , the intermediate cover  270 , and the upper cover  250  are interconnected through fastening screws (not shown) engaged with fastening holes  211 ,  271 , and  251  which are respectively provided thereto. 
   The cyclone main body  210  comprises a first cyclone body  221  constituting the first cyclone chamber  220 , and a plurality of second cyclone bodies  231  constituting the second cyclone chamber  230 . 
   The first cyclone chamber  220  separates the dust from external air drawn in through the suction path  311 . For this, the first cyclone chamber  220  is formed inside the cyclone main body  210 , being defined by the first cyclone body  221  having a tubular shape mounted inside an outer wall  212  of the cyclone main body  210 , a ceiling  224 , and a bottom surface  223 . An upper end of the first cyclone chamber  220  is opened through a first outlet  222 . A first inlet  280  is formed at the bottom surface  223  to guide the air into the first cyclone chamber  220 . According to this structure, the air is drawn into the first cyclone chamber  220  by sequentially passing through the suction assembly  350  ( FIG. 5 ), the suction path  311  ( FIG. 5 ), the dust collecting chamber  320  ( FIG. 5 ), and the first inlet  280  and is raised in a rotating manner toward the first outlet  222 . As aforementioned, for smooth rotation of the air, a guide member  285  is formed at the bottom surface  223  partially spirally formed to surround an upper part of the first inlet  280  and sloped upward as going to an outlet  286  thereof. 
   The first cyclone chamber  220  is connected to the first dust discharge port  225  formed on an upper part of an outer circumference thereof. The first dust discharge port  225  of this embodiment is disposed between the upper end of the first cyclone body  221  and the ceiling  224  in a manner that the first cyclone body  221  is apart from the ceiling  224  by a predetermined distance d 1 . In addition, the first dust discharge port  225  is connected to the first dust collection chamber  228  surrounding the outer circumference of the first cyclone body  221 . Here, the first dust collection chamber  228  is defined by an inner surface of an inner wall  229  of the cyclone main body  210  and an outer surface of the first cyclone body  221 . The inner wall  229  has a tubular shape and is disposed in the outer wall  212  of the cyclone main body  210  to surround the outer surface of the first cyclone body  221  at a predetermined distance. The first outlet  222  is formed at an end of a discharge pipe  226  protruded downward by a predetermined distance d 2  from the ceiling  224 . The discharge pipe  226  has an enough length so that the first outlet  222  is disposed lower than the first dust discharge port  225 . By the above-structured discharge pipe  226 , the ascending rotary air current in the first cyclone chamber  220  can be restrained from being directly discharged through the first outlet  222  when reaching the upper end of the first cyclone chamber  220 . Therefore, the dust included in the air being discharged from the first cyclone chamber  220  can be reduced. An opened upper end of the discharge pipe  226  is fluidly communicated with a second inlet  233  of each second cyclone chamber  230  through the first connection path  232  of the intermediate cover  270  disposed at an upper part of the cyclone main body  210 . 
   According to the present embodiment, a dedicated grill member  294  is further provided to the first outlet  222  for higher dust separation efficiency. The discharge pipe  226  according to the present invention, in addition, has a skirtlike form expanding toward the upper end. Therefore, the air rotated at the upper end of the first cyclone chamber  220  is guided to the first dust discharge port  225 , thereby improving the dust separation efficiency. 
   The second cyclone chamber  230  separates relatively smaller dust D 2  which is not yet separated by the first cyclone chamber  220 . In other words, the second cyclone chamber  230  separates the dust D 2  which is relatively smaller than dust D 1  separated by the first cyclone chamber  220 . In order to separate dust in the above manner, a plurality of the second cyclone chambers  230  are provided to the cyclone main body  210  to radially surround the first cyclone chamber  220 . Since the first inlet  280  connected to the first cyclone chamber  20  penetrates the bottom surface  223  of the first cyclone chamber  220 , the second cyclone chambers  230  are provided in the number enough to completely surround the first cyclone chamber  220 . Accordingly, the dust separation efficiency can be improved. 
   The second cyclone chambers  230  are formed in the cyclone main body  210  as partitioned by the second cyclone bodies  231 , respectively. The second cyclone bodies  231  are opened at the upper end to be connected to the second inlets  233  and the second outlets  235  formed at the intermediate cover  270 , respectively. Also, the second cyclone bodies  231  are formed as an inverse cone having a second dust discharge port  237  at the lower end so that the relatively smaller dust D 2  can be separated as the air drawn in through the second inlets  233  descends in a rotating manner therein. The second dust discharge port  237  is disposed at an upper part of the second dust collection chamber  207  formed between the inner surface of the outer wall  212  and the outer surface of the inner wall  229  of the cyclone main body  210 . In this case, size of the first dust collection chamber  228  is relevant to that of the second cyclone body  231 . More specifically, as a diameter of the second cyclone body  231  increases, the second dust collection chamber  207  is expanded, thereby decreasing size of the first dust collection chamber  228 . When capacity of the first dust collection chamber  228  is thus decreased, it is inconvenient because the first dust collection chamber  228  collecting larger amount of the dust than the second collection unit  207  should be emptied so frequently. 
   To overcome the above problem, the respective second cyclone bodies  231  are tilted so that part of a sidewall of each second cyclone body  231 , facing the outer wall of the cyclone main body  210 , is disposed parallel with the outer wall  212  of the cyclone main body  210 . In addition, the second inlet  233  and the second outlet  235  formed at the intermediate cover  270  are tilted accordingly. Therefore, a distance d 3  between the outer wall  212  and the inner wall  229 , that determines the size of the second dust collection chamber  207 , can be reduced to be substantially equal to an inner diameter of the second outlet  235 . 
   In the cyclone main body  210  according to the present embodiment, lower ends of the first and the second dust collection chambers  228  and  207  can be opened and closed selectively by a lower cover  240 . For airtightness of the cyclone main body  210 , the lower cover  240  comprises connection grooves  245 ,  244 , and  243  having substantially annular shapes to receive lower ends of the first cyclone body  221 , the inner wall  229 , and the outer wall  212 , respectively. The lower cover  240  is integrally formed with a suction duct  241  surrounding the first inlet  280 . The suction duct  241  is inserted in a mounting opening  325  formed at the bottom surface  321  of the dust collecting chamber  320 . Therefore, the cyclone dust separating apparatus  200  can be correctly positioned when the suction path  111  and the first inlet  280  are connected to each other by mounting the cyclone dust separating apparatus  200 . Also, at this time, the suction path  111  and the first inlet  280  can be connected without causing leakage of air. 
   Hereinafter, the operation of the cyclone dust separating apparatus  200  according to an embodiment of the present invention will be described. 
   As illustrated in  FIGS. 5 through 7 , the air drawn in through the suction assembly  350  is passed through the suction path  311 , the mounting opening  325 , and the first inlet  280  and then drawn into the first cyclone chamber  220  through the lower end of the first cyclone chamber  220 . The air drawn into the first cyclone chamber  220  ascends as rotating along an inner surface of the first cyclone body  221  toward the first outlet  222 . When the drawn-in air reaches the upper end of the first cyclone chamber  220  adjacent to the first dust discharge port  225 , the relatively larger dust D 1  is separated from the drawn-in air by the centrifugal force. While descending back and passing through the grill member  294 , the dust is further separated from the air from which the larger dust D 1  is once separated. Then, the air is branchedly drawn into the respective second cyclone chambers  230  after sequentially passing through the first outlet  222 , the first connection path  232 , and the second inlet  233 . The air drawn into the respective second cyclone chambers  230  descends in a rotating manner along the inner surface of the second cyclone bodies  231 . During this, the dust D 2 , relatively smaller than the dust D 1  separated in the first cyclone chamber  220 , is separated and collected in the second dust collection chamber  207  through the second dust discharge port  237 . The air, from which the smaller dust D 2  is separated, ascends back and is discharged from the second cyclone chambers  230  through the second outlet  235 . The discharged air is passed through a space formed between the upper cover  250  and the intermediate cover  270  and discharged to the discharge path  315  through an air discharge pipe  290  which is the third outlet formed at one side of the upper cover  250 . 
   According to the present embodiment, the cyclone dust separating apparatus  200  further comprises a filter member  295  between the upper cover  250  and the intermediate cover  270  so as to finally filter the air discharged through the air discharge pipe  290 . The filter member  295  is supported by a support rib  252  formed in the upper cover  250  and an upper surface of the intermediate cover  270 . According to this structure, as the air drawn into the cyclone dust separating apparatus  200  is passed through the first cyclone chamber  220 , the grill member  294 , the second cyclone chamber  230 , and the filter member  295 , the dust can be separated through multi-steps. 
   According to the above description, the inlet guiding the air to the first cyclone chamber and the outlet guiding the air discharged from the first cyclone chamber are distantly disposed from each other, that is, at the upper end and the lower end of the first cyclone chamber, respectively. Therefore, collision between the ascending air and the descending air can be minimized, thereby restraining loss of the suction force of the cyclone dust separating apparatus. 
   Furthermore, since the air is drawn into the first cyclone chamber through the lower end of the bottom surface, arrangement of the other cyclone chambers such as the second cyclone chamber becomes flexible, thereby helping downsize the cyclone dust separating apparatus. 
   In addition, according to second embodiment of the present invention, dust separation efficiency can be further enhanced by separating the dust through multi-steps by the plurality of cyclone chambers and the dedicated grill member and filter member. 
   While the invention has been shown and described with reference to certain embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.