Abstract:
A cyclonic separating apparatus includes a cyclonic separator for separating dirt and dust from an airflow, an inlet to the cyclonic separator and a shroud comprising a wall having a multiplicity of through-holes forming an outlet from the cyclonic separator. The apparatus also includes a plurality of separate passageways provided immediately downstream of the through-holes. By providing this arrangement, the separate passageways can be located around other parts of the cyclonic separating apparatus inwardly of the shroud, allowing for better packaging of the components of the cyclonic separating apparatus. The shroud may be reduced in size because some of the space previously required for a single, large passageway can be used for other components of the cyclonic separating apparatus such a collector or a cyclone. The reduction in size of the shroud in turn allows for the cyclonic separating apparatus to be more compact.

Description:
REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims the priority of United Kingdom Application No. 0721468.7, filed Nov. 1, 2007, the contents of which are incorporated herein by reference. 
       FIELD OF THE INVENTION 
       [0002]    The present invention relates to cyclonic separating apparatus. Particularly, but not exclusively, the present invention relates to cyclonic separating apparatus for a vacuum cleaner. 
       BACKGROUND OF THE INVENTION 
       [0003]    Vacuum cleaners which utilise cyclonic separators are well known. Examples of such vacuum cleaners are shown in EP 0 042 723, EP 1 370 173 and EP 1 268 076. In general, an airflow in which dirt and dust is entrained enters a first cyclonic separator via a tangential inlet which causes the airflow to follow a spiral or helical path within the first cyclonic separator so that the dirt and dust is separated from the airflow. Relatively clean air passes out of the first cyclonic separator while the separated dirt and dust is collected therein. In some applications, and as described in EP 0 042 723, the airflow is then passed to a second cyclonic separator which is capable of separating finer dirt and dust than the first cyclonic separator. 
         [0004]    However, a common problem is that larger particles of dirt and dust (for example, fluff or hair) not separated by the first cyclonic separator are able to pass into the second cyclonic separator, resulting in potential blockages and a loss of separation efficiency. Therefore, it has been found useful to position a barrier member, known as a shroud, in the airflow path between the first cyclonic separator and the second cyclonic separator. An example of a typical shroud is shown in EP 0 800 360. 
         [0005]    A shroud typically includes a wall having a large number of through-holes which communicate on their upstream side with the first cyclonic separator. The through-holes of the shroud thus form an outlet from the first cyclonic separator. In use, the through-holes of the shroud prevent larger particles of dirt and dust from passing therethrough. However, smaller particles of dirt and dust not separated by the first cyclonic separator pass through the through-holes in the shroud and into a passageway leading to the inlet to the second cyclonic separator. 
         [0006]    EP 1 377 196 describes a passageway in the form of an annular passageway located downstream of a shroud. Baffles are located in the annular passageway remote from the shroud to divide the airflow between a plurality of cyclones which form the second cyclonic separator. 
         [0007]    An alternative passageway arrangement is shown in EP 1 786 568, which discloses a shroud for a vacuum cleaner having two cyclonic separators. The shroud forms an outlet from the first cyclonic separator, and a passageway is located downstream of the shroud. A plurality of baffles is located on the inner surface of the shroud in the passageway. The passageway forms a communication path between the shroud and the inlets to a plurality of cyclones forming part of a second cyclonic separator. The bodies of the cyclones extend through the passageway and into a collector located below the passageway. Such an arrangement is well known for cyclonic separating apparatus having two cyclonic separators. 
         [0008]    However some, more recent, vacuum cleaners include cyclonic separating apparatus which has more than two cyclonic separators or separation stages. Cyclonic separating apparatus including three cyclonic separators is disclosed in WO 2006/125944. In the arrangement described therein, three collectors for dirt and dust are provided—one for each cyclonic separator. 
         [0009]    In such an arrangement, the increased number of cyclonic separators and collectors reduce the space available for the passageway downstream of the shroud. To provide sufficient space to accommodate the passageway, the diameter of the shroud may be increased, leading to an undesirable increase in the overall size of the cyclonic separating apparatus. 
       SUMMARY OF THE INVENTION 
       [0010]    It is an object of the present invention to provide cyclonic separating apparatus which is more compact than known arrangements. It is a further object of the invention to provide an arrangement of passageways within a cyclonic separating apparatus which allow more efficient use of space when compared to known arrangements. 
         [0011]    According to the invention, there is provided cyclonic separating apparatus comprising a cyclonic separator for separating dirt and dust from an airflow, an inlet to the cyclonic separator and a shroud comprising a wall having a multiplicity of through-holes forming an outlet from the cyclonic separator, wherein a plurality of separate passageways are provided immediately downstream of the through-holes. 
         [0012]    By providing such an arrangement, the separate passageways can be located around other parts of the cyclonic separating apparatus inwardly of the shroud, allowing for better packaging of the components of the cyclonic separating apparatus. This allows the shroud to be reduced in size because some of the space previously required for a single, large passageway can be used for other components of the cyclonic separating apparatus; for example, a collector or a cyclone. The reduction in size of the shroud in turn allows for the cyclonic separating apparatus to be more compact. 
         [0013]    Further, the above arrangement reduces the likelihood of larger particles of dirt and dust causing blockages downstream of the shroud. This is because the provision of a plurality of separate passageways immediately downstream of the shroud reduces stagnation of the airflow downstream of the shroud. Therefore, there is less opportunity for larger particles of dirt and dust to build up in the region immediately downstream of the shroud. 
         [0014]    Preferably, the passageways are arranged around the inner circumference of the shroud. This arrangement allows the inner surface of the shroud to form a part of the passageways, which reduces the length of the passageway and the amount of material required to form the passageway. Both of the above help to reduce the size of the cyclonic separating apparatus. 
         [0015]    Preferably, the through-holes are arranged in a plurality of separate groups, each group corresponding to a single passageway. By arranging the through-holes in a plurality of groups, the passageways can be kept separate from one another while still in communication with the optimum number of through-holes. 
         [0016]    Preferably, a further cyclonic separator is provided downstream of the cyclonic separator. More preferably, the further cyclonic separator has a collection area for collecting separated dirt and dust and a plurality of channels connecting the further cyclonic separator with the collection area. More preferably, the collection area and the plurality of channels form a collector for the further cyclonic separator. 
         [0017]    Preferably, the channels are located between adjacent passageways. This arrangement is compact and uses the available space effectively. 
         [0018]    Preferably, a common wall separates the passageways from the channels. By providing a common wall between the channels and the passageways, the structure is simplified, space is saved and manufacturing costs are reduced. 
         [0019]    Preferably, the passageways communicate with an inlet to the further cyclonic separator. 
         [0020]    Preferably, an intermediate cyclonic separator is provided downstream of the cyclonic separator and upstream of the further cyclonic separator. An additional stage of cyclonic cleaning is useful to improve the overall separation efficiency of the cyclonic separating apparatus. 
         [0021]    Preferably, the intermediate cyclonic separator is located inwardly of the passageways. 
         [0022]    This arrangement is compact and makes best use of the available space inwardly of the shroud. 
         [0023]    Preferably, the passageways communicate with an inlet to the intermediate cyclonic separator. More preferably, a duct is located upstream of the inlet to the intermediate cyclonic separator, the duct being in communication with each of the passageways. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0024]    An embodiment of the invention will now be described with reference to the accompanying drawings, in which: 
           [0025]      FIG. 1  is a side view of a cylinder vacuum cleaner including cyclonic separating apparatus according to the invention; 
           [0026]      FIG. 2  is a plan view of the cylinder vacuum cleaner of  FIG. 1 ; 
           [0027]      FIG. 3  is a side view of the cyclonic separating apparatus removed from the remainder of the cylinder vacuum cleaner of  FIG. 1 ; 
           [0028]      FIG. 4  is a section through the cyclonic separating apparatus of  FIG. 3  taken along the line A-A of  FIG. 3 ; 
           [0029]      FIG. 5  is a side section through the cyclonic separating apparatus of  FIG. 3  taken along the line B-B of  FIG. 4 ; and 
           [0030]      FIG. 6  is an exploded view of parts of the cyclonic separating apparatus of  FIG. 3 . 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0031]    A cylinder vacuum cleaner  10  incorporating cyclonic separating apparatus according to the invention is shown in  FIGS. 1 and 2 . The vacuum cleaner  10  has a main body  12  housing a motor and fan unit (not shown) and to which a pair of wheels  14  is attached. The wheels  14  allow the main body  12  of the vacuum cleaner  10  to be maneuvered across a floor surface. A dirty air inlet  16  is formed on the main body  12 . A hose and wand assembly (not shown) can be connected to the dirty air inlet  16  in order to enable a user to clean a floor surface. 
         [0032]    Cyclonic separating apparatus  100  according to the invention is releasably attached to the main body  12 . The interior of the cyclonic separating apparatus  100  is in communication with the dirty air inlet  16  through which a dirt-laden airflow enters the cyclonic separating apparatus  100 . The cyclonic separating apparatus  100  can be removed from the main body  12  for emptying purposes. 
         [0033]    The cyclonic separating apparatus  100  is shown in more detail in  FIGS. 3 to 6 , in which the cyclonic separating apparatus  100  is shown removed from the remainder of the vacuum cleaner  10  for clarity. Firstly referring to  FIG. 3 , the cyclonic separating apparatus  100  comprises an upper portion  102  and a lower portion  104 . The upper and lower portions  102 ,  104  are separable from one another to allow parts of the cyclonic separating apparatus  100  to be cleaned. The upper portion  102  includes a handle  106  for carrying the cyclonic separating apparatus  100 . The handle  106  can also be used to carry the entire vacuum cleaner  10  if the cyclonic separating apparatus  100  is attached thereto. 
         [0034]    The lower portion  104  has a substantially cylindrical outer wall  108  and a base  110 . The outer wall  108  and the base  110  delimit a first cyclonic separator  112  and a first collector  114 . Dirt and dust is separated by the first cyclonic separator  112  and collected in the first collector  114 . An inlet  116  is formed in the outer wall  108 . The inlet  116  forms a communication path between the dirty air inlet  16  and the interior of the first cyclonic separator  112 . The air inlet  116  is arranged tangentially to the first cyclonic separator  112  so that the incoming air is forced to follow a helical path around the interior of the outer wall  108 . The base  110  is openable for emptying purposes. The base  110  is pivoted about a hinge  118  and held in place by a catch  120 . 
         [0035]    A shroud  122  is located inwardly of the outer wall  108  of the first cyclonic separator  112 . The shroud  122  comprises a wall  124  having a cylindrical lower part and a tapered upper part. A plurality of through-holes  126  is formed in the wall  124  and forms an outlet from the first cyclonic separator  112 . The through-holes  126  are arranged in a plurality of groups  128  spaced around the circumference of the wall  124 . A lip  130  is provided at the base of the shroud  122  and depends therefrom. The lip  130  includes a plurality of through-holes  132  arranged in rows around the circumference thereof. The lip  130  helps to prevent separated dirt and dust from being re-entrained back into the airflow within the first cyclonic separator  112 . 
         [0036]    Referring now to  FIGS. 4 to 6 , a plurality of passageways  134  are formed immediately downstream of the through-holes  126 . Each passageway  134  corresponds to a single group  128  of through-holes  126  and is delimited by the inner surface of the wall  124  of the shroud  122  and a passageway wall  136 . The passageways  134  are spaced around the inner circumference of the shroud  122 . This is best shown in  FIG. 4 . A partition  137  is located on either side of each passageway  134  at a lower end thereof (see  FIG. 6 ). Therefore, the lower end of each passageway  134  is separated from an adjacent passageway  134  by a partition  137 . This is shown most clearly in  FIG. 6 . The passageways  134  extend upwards away from the through-holes  126  and become narrower but deeper in the downstream direction. In other words, in the downstream direction, the passageways  134  reduce in width in a circumferential direction but increase in depth in a radial direction. This can be seen most clearly in  FIGS. 5 and 6 . In this embodiment, the minimum depth of the passageways  134  in a radial direction is 8.5 mm. 
         [0037]    A duct  138  ( FIG. 5 ) is located at the upper end of the passageways  134 . The duct  138  is an annular space which is in communication with each passageway  134 . The duct  138  provides a communication path between the passageways  134  and a second cyclonic separator  139 . The duct  138  allows the individual airflow paths from the passageways  134  to be recombined before passing into the second cyclonic separator  139 . This arrangement helps to keep the pressure of the air entering the second cyclonic separator  139  more constant. The second cyclonic separator  139  comprises a single cyclone  140  located inwardly of the passageways  134 . The single cyclone  140  has an air inlet  142  and an air outlet  144 , both of which are located at a first end of the single cyclone  140 . A cone opening  146  is located at a second end of the single cyclone  140 . 
         [0038]    A second collector  148  is also located at the second end of the single cyclone  140  and is in communication with the cone opening  146 . The second collector  148  is delimited by a wall  150  which depends from an outer surface of a wall delimiting the duct  138  and which is located inwardly of the shroud  122  and the passageway walls  136 . The air outlet  144  of the single cyclone  140  is in communication with a duct  152 . The duct  152  provides a communication path between the second cyclonic separator  139  and a third cyclonic separator  154 . Therefore, the second cyclonic separator  139  acts as an intermediate cyclonic separator between the low-efficiency first cyclonic separator  112  and a high-efficiency third cyclonic separator  154 . 
         [0039]    The third cyclonic separator  154  comprises a plurality of high-efficiency cyclones  156  arranged in parallel. In this embodiment, eighteen high-efficiency cyclones  156  are provided. Fourteen high-efficiency cyclones  156  are arranged in a ring around the outer circumference of the upper part  102  of the cyclonic separating apparatus  100 . A part of each of the high-efficiency cyclones  156  in this ring forms a part of the outer surface of the cyclonic separating apparatus  100 , as shown in  FIGS. 3 and 5 . The remaining four high-efficiency cyclones  156  (shown in  FIG. 4 ) are located inwardly of the ring of fourteen high-efficiency cyclones  156 . Each high-efficiency cyclone  156  has a tangentially-arranged air inlet  158  and an air outlet  160 . Each air inlet  158  and air outlet  160  is located at a first end of the respective high-efficiency cyclone  156 . A cone opening  162  is located at a second end of each high-efficiency cyclone  156 . 
         [0040]    A third collector  164  is located at the second end of the high-efficiency cyclones  156  and is in communication with the cone openings  162  of the high-efficiency cyclones  156 . The third collector  164  comprises an annular base portion  166  and a plurality of connecting channels  168 . The base portion  166  acts as a collection area for separated dirt and dust and is delimited by a cylindrical wall  170  and the outer surface of wall  150 . The channels  168  provide a communication path between each of the cone openings  162  and the base portion  166 . Each channel  168  corresponds to a single high-efficiency cyclone  156  and is delimited by the outer surfaces of the passageway walls  136  and the wall  150 . Therefore, the passageways  134  and channels  168  are separated from one another by the passageway walls  136 . This is shown most clearly in  FIG. 4 . The channels  168  and passageways  134  are arranged alternately around the inner circumference of wall  124  so that the channels  168  are located between adjacent passageways  134 . This arrangement is advantageous because both the passageways  134  and the channels  168  can be accommodated in one annular space, without the need to increase the diameter of the wall  124  of the shroud  122 . 
         [0041]    As shown in  FIG. 4 , a part of each high-efficiency cyclone  156  in the ring of fourteen high-efficiency cyclones  156  is also located between adjacent passageways  134 . In this embodiment, the cone opening  162  of each of the high-efficiency cyclones  156  in the ring is spaced from a respective passageway wall  136  by a distance approximately equal to the diameter of the cone opening  162  in order to reduce the risk of re-entrainment of dirt and dust separated by the high-efficiency cyclones  156  back into the airflow leaving the third cyclonic separator  154 . 
         [0042]    The air outlets  160  of the high-efficiency cyclones  156  are in communication with an outlet  172 . The outlet  172  provides an airflow path from the cyclonic separating apparatus  100  into other parts of the vacuum cleaner  10 . Located downstream of the outlet  172  is a pre-motor filter (not shown), the motor and fan unit and a post-motor filter (not shown). 
         [0043]    In use, the motor and fan unit draws a flow of dirt-laden air through the hose and wand, into the dirty air inlet  16 , through the inlet  116  and into the cyclonic separating apparatus  100 . Due to the tangential arrangement of the inlet  116 , the airflow is forced to follow a helical path around the interior of the outer wall  108 . Therefore, larger dirt and dust particles are separated by cyclonic motion in the first cyclonic separator  112 . These particles are collected in the first collector  114 . 
         [0044]    The partially-cleaned airflow then flows back up the interior of the first cyclonic separator  112  and exits the first cyclonic separator  112  via the through-holes  126  in the shroud  122 . Once the airflow has passed through the through-holes  126 , it is divided between the plurality of passageways  134  immediately downstream of the through-holes  126 . The airflow moves up the passageways  134  and passes into the duct  138  whereupon the airflows from each of the passageways  134  are re-combined. The airflow then moves from the duct  138  into the inlet  142  of the single cyclone  140  of the second cyclonic separator  139 . The single cyclone  140  has a diameter smaller than the outer wall  108  of the first cyclonic separator  112  and is tapered. Therefore, the single cyclone  140  is able to separate smaller particles of dirt and dust from the partially-cleaned airflow than the first cyclonic separator  112 . Separated dirt and dust exits the single cyclone  140  via the cone opening  146  and is collected in the second collector  148 . The cleaned air then flows back up the centre of the single cyclone  140 , exits the single cyclone  140  through the air outlet  144  and passes into the duct  152 . 
         [0045]    From duct  152 , the airflow is then divided between the tangential air inlets  158  of the eighteen high-efficiency cyclones  156  of the third cyclonic separator  154 . Each of the high-efficiency cyclones  156  has a diameter smaller than that of both the first cyclonic separator  112  and the single cyclone  140  of the second cyclonic separator  139 . Therefore, the high-efficiency cyclones  156  are able to separate even finer particles of dirt and dust from the airflow than either of the first or second cyclonic separators  112 ,  138 . Separated dirt and dust exits the high-efficiency cyclones  156  via the cone openings  162  and passes into the third collector  164 . Once in the third collector  164 , the separated dirt and dust passes down the channels  168  and is collected in the base portion  166 . 
         [0046]    Cleaned air then flows back up the high-efficiency cyclones  156 , exits the high-efficiency cyclones  156  through the air outlets  160  and enters the outlet  172 . The cleaned air then passes from the outlet  172  sequentially through the pre-motor filter, the motor and fan unit, and the post-motor filter before being exhausted from the vacuum cleaner  10  through air vents (not shown) located on the outer surface of the vacuum cleaner  10 . 
         [0047]    When a cleaning operation is finished, the collectors  114 ,  148 ,  164  of the cyclonic separating apparatus  100  may be full of dirt and dust, and require emptying. To do this, the user switches off the vacuum cleaner  10  and removes the cyclonic separating apparatus  100  from the main body  12  by pressing a release catch (not shown). Using the handle  106 , the user then places the cyclonic separating apparatus  100  over a suitable receptacle such as a dustbin and presses a further release button (not shown) in order to release the base  110 . 
         [0048]    When released, the base  110  pivots downwardly about the hinge  112  so that the dirt and dust collected in the first, second and third collectors  114 ,  148 ,  164  can thus be emptied conveniently and efficiently. The first, second and third collectors  114 ,  148 ,  164  are emptied simultaneously during this process. 
         [0049]    When the cyclonic separating apparatus  100  has been emptied as described above, the user manually moves the base  110  back into the closed position shown in  FIG. 3 . The cyclonic separating apparatus  100  can then be replaced on the main body  12  of the vacuum cleaner  10  (as shown in  FIGS. 1 and 2 ) for further cleaning operations. 
         [0050]    The invention is not limited to the detailed description given above. Variations will be apparent to the person skilled in the art. For example, the passageways need not be arranged around the entirety of the inner circumference of the shroud. They may be arranged only around a part of the inner circumference of the shroud. Alternative arrangements, such as spiral passageways or rows of passageways could also be used. 
         [0051]    Additionally, the through-holes in the shroud need not be arranged in a plurality of groups. The through-holes may be arranged in rows or columns, with each passageway corresponding to a row, a column or a part thereof. 
         [0052]    Any number of cyclonic separators may be provided. For example, a single cyclonic separator may be provided with, optionally, a filter or other separating media downstream of the shroud. Alternatively, two cyclonic separators may be provided in series. Any number of cyclones may be used in each cyclonic separator. Additionally, any number of collectors could be used to collect separated dirt and dust. 
         [0053]    The channels, although preferred, are not essential to the invention. Further, if channels are provided, they need not form part of the third collector. They may form part of the first or second collectors, or may take the form of a plurality of conduits which lead into a separate collector. 
         [0054]    The cleaning appliance need not be a cylinder vacuum cleaner. The invention is applicable to other types of vacuum cleaner, for example, upright machines, stick-vacuums or hand-held cleaners. Further, the present invention is applicable to other types of cleaning appliances, for example, a wet and dry machine or a carpet shampooer.