Patent Publication Number: US-6221134-B1

Title: Apparatus and method for separating particles from a cyclonic fluid flow

Description:
FIELD OF THE INVENTION 
     The present invention relates generally to cyclonic separators. In one particular application, the invention relates to the cyclonic separation of particulate material from an air flow. 
     BACKGROUND OF THE INVENTION 
     The use of a cyclone, or multiple cyclones connected in parallel or series, has long been known to be advantageous in the separation of particulate matter from a fluid stream. Typically, a relatively high speed fluid stream is introduced tangentially to a generally cylindrical or frusto-conical container, wherein the dirty air stream is accelerated around the inner periphery of the container. The centrifugal acceleration caused by the travel of the fluid in a cyclonic stream through the cyclone causes the particulate matter to be disentrained from the fluid flow and, eg., to collect at the bottom of the container. A fluid outlet is provided for the extraction of the fluid from the centre of the top of the cyclone container, as is well known in the art. 
     A typical flow path in a cyclone separator is as follows. Fluid to be treated is introduced tangentially at a fluid inlet located at an upper end of the cyclone container. The fluid stream rotates around the inner surface of the cyclone container, and spirals generally downwardly around the inner surface of the container (if the cyclone container is vertically disposed). At a bottom end of the cyclone container the fluid stream travels radially inwardly, generally along the bottom of the container and then turns upwardly and proceeds vertically up and out of the cyclone container. The particulate matter separating action of the cyclonic flow occurs substantially around the inner surface of the container. Once the fluid moves inwardly to the centre of the container, and upwardly therethrough, there is little or no dirt separation achieved. 
     The difficulty experienced with prior art cyclonic separators is the reentrainment of the deposited particles back into the outgoing fluid flow. Deposited particles exposed to a high speed cyclonic flow thereover have a tendency to be reentrained. This is particularly problematic when the container has a solid bottom portion in which the dirt collects. However, there is a potential reentrainment problem even if the bottom of the container has a passageway provided in the bottom thereof to convey the separated particulate material away from the container. 
     If a high degree of separation is required, it is known to connect a plurality of cyclones in series. While using several cyclones in series can provide the required separation efficiency, it has several problems. First, if the separators are to be used in industry, they generally need to accommodate a high flow rate (eg. if they are to be used to treat flue gas). The use of a plurality of cyclones increases the capital cost and the time required to manufacture and install the separators. Further, the use of a plurality of cyclones increases the space requirements to house the cyclones. Accordingly, there is a need for an improved anti-reentrainment means for cyclonic separators. 
     SUMMARY OF THE INVENTION 
     In has now been discovered that a single cyclone having improved efficiency (eg. up to 99% efficiency) may be manufactured by positioning in the cyclone chamber a member for creating a dead air space beneath the cyclonic flow region of the cyclone chamber wherein the dead air space is in communication with the cyclonic flow region by a plurality of openings in the member. The openings are provided on the radial outer portion, the radial inner portion or both the radial outer portion and the radial inner portion of the member. This construction effectively traps separated material beneath the cyclonic flow region and inhibits the reentrainment of the separated material. Thus, a single cyclone may be used in place of a plurality of cyclones to achieve the same separation efficiency. 
     In accordance with the instant invention, there is provided a separator for separating entrained particles from a fluid flow, the separator comprising a cyclone chamber an outer wall and a cyclonic flow region, the cyclonic flow region having a radial width, an outer peripheral portion, a medial portion disposed interior of the peripheral portion and an inner portion disposed interior of the medial portion, a fluid inlet for introducing a cyclonic fluid flow to the cyclonic flow region, a fluid outlet for removing the fluid flow from the cyclone chamber, a particle separating member positioned in the cyclone chamber beneath at least a portion of the cyclonic flow region, the particle separating member having a plurality of apertures, and a particle receiving chamber disposed beneath the particle separating member for receiving particles passing into the particle receiving chamber through the apertures wherein the apertures are disposed on the particle separating member such that the medial portion of the cyclonic flow region is substantially free from said apertures. 
     The separator may be used in an upright vacuum cleaner. Accordingly, the separator may further comprise a cleaner head adapted for movement over a floor and having a fluid nozzle positionable adjacent the floor, the nozzle in fluid flow communication via a passageway with the separator fluid inlet, a handle for moving the cleaner head over the floor, and a casing for housing the cyclone chamber. The casing is preferably pivotally mounted to the cleaner head. The separator may be used in a canister or a central vacuum cleaner. Accordingly, the passageway may further comprise a flexible portion that is positioned external of the cleaner head and the casing and the handle is affixed to the cleaner head. 
     In one embodiment, the apertures are sized to inhibit elongate particles from passing there through, whereby elongate particles collect on top of the particle separating member. 
     In another embodiment, the apertures are shaped to aerodynamically direct particles from the cyclonic flow region into the particle receiving chamber. 
     The particle separating member may extend under all of the cyclonic flow region to define bottom surface of the cyclonic flow region. Alternately, it may extend only under that portion of the cyclonic flow region in which the apertures are to be provided. For example, the particle separating member may extend essentially under only the outer peripheral portion, the inner portion or both the peripheral and inner portions of the cyclonic flow region. 
     In accordance with the instant invention, there is also provided a separator for separating entrained particles from a fluid flow, the separator comprising a cyclone chamber for containing a cyclonic flow in a cyclonic flow region, the cyclonic flow region having a radial width, an outer peripheral portion, a medial portion disposed interior of the peripheral portion and an inner portion disposed interior of the medial portion, means for introducing a fluid flow to the cyclone flow region for cyclonic rotation therein, means for removing the fluid flow from the cyclone chamber, particle receiving means disposed beneath the cyclone flow region for receiving particles separated from the fluid flow, separation means for dividing the particle receiving means from the cyclone chamber, and transporting means associated with the separation means for connecting the particle receiving means in flow communication with the cyclonic flow region such that, in operation, particles pass through the transporting means to the particle receiving means wherein said transporting means are positioned outside the medial portion of the cyclonic flow region. 
     In one embodiment, the particle receiving means comprises a sealed chamber except for the transporting means and the separator further comprises emptying means for emptying the particle receiving means. 
     In another embodiment, the separator further comprises means for connecting the particle receiving means in flow communication with a conduit for transporting separated particles downstream from the particle receiving means. 
     In another embodiment, the separator further comprises aerodynamic means associated with the transporting means for directing particles from the cyclonic flow region into the particle receiving means. 
     In another embodiment, the particle separating means extends under all of the cyclonic flow region to define bottom surface of the cyclonic flow region. 
     In another embodiment, the transporting means are positioned beneath only one or both of the peripheral and inner portions of the cyclonic flow region. 
     In another embodiment, the transporting means are distributed regularly around the separating means. 
     In another embodiment, the fluid contacts only a portion of the separating means and the transporting means are positioned only in said portion. 
     In another embodiment, the transporting means comprise openings in the separation means. 
     In accordance with the instant invention, there is also provided a method for separating entrained particles from a fluid flow, the method comprising the steps of introducing a fluid to flow cyclonically in a chamber having a cyclonic flow region, the cyclonic flow region having a radial width, an outer peripheral portion, a medial portion disposed interior of the peripheral portion and an inner portion disposed interior of the medial portion, removing particles from the fluid flow in the cyclone chamber via passages provided beneath one or both of the peripheral and inner portions, and removing the fluid flow from the chamber. 
     In one embodiment, the method further comprises the steps of storing the particles removed from the fluid flow and inverting the chamber to remove the separated particles. 
     In another embodiment, the method further comprises the step of transporting separated particles downstream from the chamber. 
     In another embodiment, the separator comprises the dirt separation mechanism for a vacuum cleaner and the method further comprises passing a cleaning head over a surface to clean the surface. 
     In another embodiment, the method further comprises directing particles to pass into the passages. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     For a better understanding of the present invention, and to show more clearly how it may be carried into effect, reference will now be made by way of example to the accompanying drawings of a preferred embodiment of the present invention, in which: 
     FIG. 1 is an isometric view of a cyclone separator according to the present invention; 
     FIG. 2 is a cross-sectional view along the line  2 — 2  in FIG. 1; 
     FIGS. 3 a - 3   c  are cross-sectional views along the line  2 — 2  in FIG. 1 showing various configurations of the particle separation member of the present invention; 
     FIGS. 4 a  and  4   b  are cross-sectional views along the line  2 — 2  in FIG. 1 of the cyclonic flow region in alternate embodiments of the device of FIG. 1; 
     FIGS. 5-7 a  are top plan views of various alternate configurations of the particle separation member of the present invention; 
     FIG. 7 b  is a side sectional view of a cyclone separator incorporating the particle separation member of FIG. 7 a;    
     FIG. 8 is a sectional side view of an alternate embodiment of the particle separator member of the present invention; 
     FIG. 9 is an isometric view of a second alternate embodiment of the particle separator member of the present invention; 
     FIG. 10 is an isometric view of a third alternate embodiment of the particle separator member of the present invention; 
     FIG. 11 is an enlarged cross-section view of the particle separator member of the present invention, showing aperture detail; 
     FIG. 12 is a sectional perspective view of the particle separator member having baffle members according to the present invention; 
     FIG. 13 is an enlarged bottom plan view in the direction of arrow  12  of the baffles of FIG. 12; 
     FIG. 14 is a sectional perspective view of and alternate embodiment of the baffle members according to the present invention; 
     FIG. 15 is a bottom plan view of the baffle members of FIG. 14; 
     FIG. 16 is an perspective view of a household vacuum cleaner incorporating a cyclone separator according to the present invention; 
     FIG. 17 is an enlarged perspective view of the bin of FIG. 16 when removed from the vacuum cleaner; 
     FIG. 18 is an enlarged perspective view of the access member of FIG. 17; 
     FIG. 19 is an exploded perspective view of a chamber emptying means according to the present invention; 
     FIGS. 20 a  and  20   b  are top plan views of the components of the chamber emptying means of FIG. 19; 
     FIGS. 21 a  and  21   b  are top plan views of the chamber emptying means of FIG. 19, shown in the open and closed positions, respectively; and, 
     FIGS. 22 a  and  22   b  are top plan views of an alternate embodiment of the components of the chamber emptying means according to the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The improvements in cyclonic separators described herein may be used with or in place of cyclonic separation devices of any sort which are used to separate particulate material from a fluid stream. For example, they may be used with a fluid stream consisting of one or more gasses such as industrial dust collection systems (eg. flue gas scrubbing), they may be used to classify particles according to their size or they may be used with a fluid stream consisting of one or more liquids (eg. a hydrocyclone) or with fluid streams comprising a gas/liquid mixture. It will be appreciated that they these cyclone separators may be used in any manner known in the particle separation art. 
     A cyclonic separator  30  according to the present invention is shown in FIG.  1 . In this embodiment, separator  30  has a bin  32 , an inlet  34  for delivering a cyclonic fluid flow to separator  30  and an outlet  36  for removing fluid from the separator. Inlet  34  need not be tangential but may be of any configuration which is capable of providing a cyclonic fluid flow to bin  32 , such as an axial or screw cyclone inlet. Disposed in a lower portion of bin  32  is a separation member  40  which comprises a flat, disc-like member, having an upper face  42  and a lower face  44 , and which substantially divides bin  32  into a cyclone chamber  46 , having a cyclonic flow region  48  defined therein, and a particle receiving chamber  50 . Cyclone chamber  46  and particle receiving chamber  50  communicate only via a plurality of apertures  52  in separation member  40 . Apertures  52  comprise a plurality of slits  54 , each having an upstream edge  56  and a downstream edge  58  relative to the direction of cyclonic fluid flow in cyclone chamber  46  (arrow C), longer than the transverse width and oriented generally radially with respect to bin  32 . Particle receiving chamber  50  comprise a hopper  60  having a sloping wall  62  leading to a hopper exit  64 . Hopper exit  64  communicates with a particle transport conduit  66  for transporting received particles away from receiving chamber  50 . 
     In use, a particle-laden fluid stream is introduced to cyclone chamber  46  via inlet  34  to flow cyclonically therein. The cyclonic flow proceeds rotationally around and downwardly through bin  32  until it comes into contact with separation member  40 . The fluid flow then proceeds cyclonically upwardly through a central portion of cyclonic flow region  48  in cyclone chamber  46  and is ultimately removed from cyclone chamber  46  via outlet  36 . As the cyclonic fluid flow moves cyclonically down along the inner wall of cyclone chamber  46 , it encounters separation member  40  and travels across separation member  40 . The change is speed and direction of the fluid stream as it flows through cyclone chamber  46  causes particles entrained in the fluid stream to become disentrained. These separated particles may fall downwardly due to gravity and/or the may be dragged by the fluid stream to upper surface  42 . As the separated particles encounter an aperture  52 , they tend to travel through such aperture (depending on particle size) and are transported away from cyclone chamber  46  into particle receiving chamber  50 . Some of the fluid will pass through apertures  52  carrying entrained particulate matter through separation member  40  and/or dragging separated particulate matter through separation member  40 . Hopper  60  collects these particles for removal by transport conduit  66  (such as due to gravity flow). Larger particles separated from the fluid flow by the cyclonic action and incapable of passing through apertures  52  accumulate on upper surface  42  of separation member  40 . 
     It will thus be appreciated that separation member  40  assist in particle separation in several ways. First, by providing a discontinuous surface, it disrupts the cyclonic flow thus assisting in separating entrained particulate matter from the fluid stream. Secondly, if provides an area (particle receiving chamber  50 ) which is separate from cyclone chamber  46 . If a portion of the fluid stream enters particle receiving chamber  50 , the cyclonic flow may be slowed or terminated thus allowing entrained particulate matter to separate out without the potential for reentrainment. 
     It will be appreciated that cyclone chamber  46  may be of any design known in the art. For example inlet  34  and outlet  36  may be positioned at any location and the walls of chamber  46  may be of any construction known in the art. 
     The location of apertures  52  have been found to affect the particle separation characteristics of separation member  40  for a given cyclone configuration and application. Referring to FIG. 2, it has been found that the anti-reentrainment characteristics of separation member  40  are enhanced if apertures  52  are concentrated beneath peripheral portion  70  of cyclonic flow region  48  (see FIG. 3 a ), inner portion  72  of cyclonic flow region  48  (see FIG. 3 b ), or both peripheral portion  70  and inner portion  72  (see FIG. 3 c ) thereby leaving medial portion  74  substantially free from apertures  52 . If apertures  52  are provided beneath medial portion  74  without any means provided in particle receiving chamber  50  for preventing any substantial (and preferably all) cyclonic flow in particle separating chamber  50 , then some of the particulate material in particle separation chamber  50  will be reentrained into the air flow in cyclone chamber  46 . Accordingly, it is preferred that there are no apertures  52  beneath medial portion  74  when there are no means (eg. baffles) to prevent cyclonic flow in particle separation chamber  50 . It will be appreciated that a few apertures  52  may be provided in medial portion  74  without creating substantial reentrainment. 
     Preferably, peripheral portion  70  comprises approximately the outermost one quarter of the radial width  76  of cyclonic flow region  48 , and inner portion  72  comprises approximately the innermost one quarter of the radial width  76  of cyclonic flow region  48 . Medial portion  74  therefore comprises half of the radial width  76 . 
     If a cyclone separator configuration is varied, the shape and size of cyclonic flow region  48  will vary. For example, referring to FIG. 4 a , a cyclone bin  32 ′ having a member  80  centrally position therein results in an annular-shaped cyclonic flow region  48 ′. Member  80  may be a central air feed conduit, as in the embodiment shown in FIGS. 16 and 17. Regardless of its function, for purposes of the present discussion, member  80  is any feature which occupies a portion of the cyclonic flow region thereby inhibiting cyclonic air flow in that portion of the cyclonic flow region. As a result, cyclonic flow region  48 ′ has a radial width  76 ′ between member  80  and bin  32 ′. Peripheral and inner portions  70 ′ and  72 ′, respectively, are defined in cyclonic flow region  48 ′ as described above, this time with reference to radial width  76 ′. Referring to FIG. 4 b , bin  32 ″ may have a non-cross sectional cross-section (eg. elliptical). Accordingly, the shape of cyclonic flow region  48 ″, peripheral portion  70 ″ and inner portion  72 ″ are also elliptical. Thus, the peripheral portion  70 ″ and inner portion  72 ″ will have portions having different radial widths. The cyclone may alternately have any non-curvilinear cross-section which permits a substantially cyclonic flow therein. Also, the radial width of cyclone chamber  46  may vary along its longitudinal length, and may be, eg., cylindrical, frusto-conical or any other shape having beneficial cyclonic particle separation characteristics. 
     Apertures  52  may be of any particular shape. For example, they may be circular (see FIG.  6 ), rectangular (see FIG.  12 ), triangular, or other regular or irregular shape. While apertures  52  may be any shape, in a preferred embodiment, they have a length greater than their width. In particular, as shown in FIG. 12, upstream and downstream edges  58 ,  60  are preferably longer than the spaced opposed sides  57  extending between edges  58 ,  60  (eg. edges  58 ,  60  are preferably at least twice the length of sides  57 ) so that apertures  52  define slits. 
     As shown in FIG. 1, slits  54  may extend generally radially (i.e. edges  58 ,  60  may extend generally radially). However, as shown in FIG. 5, slits  54  are preferably angled slightly, relative to radial width  76 , so that the outer edge  82  of an aperture  52  is upstream of the inner edge  84 , relative to the cyclonic air flow (indicated by arrow C). The angle α of slits  54  relative to radial width  76  may be up to 45°. 
     Apertures  52  may be equidistantly spaced apart around separation member  40  (see FIGS. 3 a - 3   c ) or they may be positioned with different spacings between adjacent apertures  52 . Further, apertures  52  may be continuously positioned around all of separation member  40  (see FIGS. 3 a - 3   c ) or apertures  52  may be positioned around only a portion of separation member  40  (see FIG. 7 a ). Distributing apertures  52  over only a region may be beneficial where only a portion of dirt separation member  40  is contacted by the cyclonic flow in bin  32  (see FIG. 7 b ). This may be used, for example, if bin  32  has a single inlet  34 . In such a case, the sector of separation member  40  which will be contacted by the cyclonic flow may be predetermined and apertures  52  provided only in that sector. 
     Also, as illustrated in FIG. 7 b , it should be noted that dust separation member  40  need not be positioned perpendicular to the cyclonic (ie. longitudinal) axis of cyclonic flow region  48  in cyclone chamber  46 . In particular separation member  40  may be at an angle to the axis. 
     Referring now to FIG. 8, separation member  40  need not extend across the entirety of cyclonic flow region  48 , but rather may be disposed in only the portion of cyclonic flow region  48  beneath which apertures  52  are to be provided. By way of example only, FIG. 8 shows a separation member  40 ′″ which comprises an annular ring  86  disposed beneath peripheral portion  70  of cyclonic flow region  48 . Particle receiving chamber  50 ′″ is disposed thereunder, between bin  32  and an inner wall  88 . It will be understood by one skilled in the art that separation member  40  may equally have any other configuration suitable for a given separator application without departing from the scope of the present invention. It will be appreciated, for example, that separator  40  may comprise an annular ring positioned beneath inner portion  72  of cyclonic flow region  48 . 
     Referring to FIGS. 9 and 10, respectively, separation member  40  need not be disc-shaped, but may also be conical or trumpet-shaped. It may be convex (i.e. it may project into particle receiving chamber  50  as shown in FIG. 10) or it may be concave (i.e. it may project away from particle receiving chamber  50 ). It will be appreciated that separation member  40  need not define a continuous surface. For example, as shown in FIG. 10, it may have a curved surface in which apertures  52  are provided and a flat central top portion  78 . 
     Particle receiving chamber  50  need not have hopper  60  thereunder. Instead, it may have a substantially closed bottom  90 , as shown in FIGS. 9 and 10. In this configuration, particles received by particle receiving chamber  50  are collected therein for subsequent emptying, as described below. This configuration may be used in a batch process operation. 
     Referring to FIG. 11, edges  56  and  58  may be aerodynamically shaped to enhance the performance of separation member  40 . For example, the thickness of particle separating member  40  is preferably reduced adjacent the upstream edge  56 . Referring to FIG. 11, aperture  52  has a sloped upstream edge  56  to assist in directing air and particles from cyclone chamber  46  to particle receiving chamber  50 . While either or both of upper surface  42  and lower surface  44  may be sloped with respect to the plane in which particle separation member  40  lies, it is preferred that upper surface  42  is sloped. It has been found that an angle of 45° is preferable. The thickness of downstream edge  58  of particle separating member  40  may be substantially unchanged. Alternately, aperture  52  is preferably shaped to have sloped downstream edge  58  to assist in directing air and particles from cyclone chamber  46  to particle receiving chamber  50 . Performance is further enhanced if downstream edge  58  has a blunt surface  92  on an upper portion thereof. Other edge configurations may also be beneficially employed. 
     The reentrainment of deposited particles into the cyclonic flow is related to the speed and degree of cyclonic flow of fluid passing over deposited particles. Accordingly, any reduction in the cyclonic flow of the fluid within the particle receiving chamber will beneficially enhance the anti-reentrainment properties of the separator. To that end, referring to FIG. 12 particle receiving chamber  50  may be provided with a plurality of baffles  100 . The baffles operate to reduce and preferably stop the cyclonic flow of air beneath particle separation member  40 . 
     Preferably, these are provided an lower surface  44  and extend away from particle separation member  40 . If separator  30  has a bottom  90 , then preferably, baffles  100  extend from lower surface  44  towards bottom  90  but do not touch bottom  90 . Baffles  100  preferably extend approximately three-quarters of the distance from lower surface  44  of separation member  40  to the bottom  90  of particle receiving chamber  50 , but may be longer or shorter if desired. Preferably baffles  100  are parallel to the longitudinal axis of cyclone bin  32 . 
     A baffle  100  is preferably disposed adjacent each aperture  52  on the downstream side, relative to cyclonic flow in cyclonic chamber  46  (arrow C). For example, a baffle  100  may be offset 15° downstream from its associated aperture  52 . It will be appreciated that a baffle  100  need not be associated with each aperture  52 . Preferably the baffles are immediately downstream of each aperture  52 . 
     Baffles  100  comprises a wall  102  which may extend radially inwardly or which may be curved. Preferably wall  102  is substantially parallel to aperture  52  along its length. Wall  102  extends at least coterminously with the length of edges  56 ,  58  apertures  52 . Preferably, wall extends at least three times the length of edges  56 ,  58 . 
     As shown in FIGS. 12 and 13, baffle  100  may also have a lateral wall  104  disposed adjacent outer and/or inner edges  82  and  84  of aperture  52 . Wall  104  preferably extends from wall  102  in the upstream direction. If an apertures  52  is disposed in peripheral portion  70 , baffle  100  preferable has one lateral wall  104  only, disposed adjacent inner edge  84 . Wall  102  is positioned inward of edge  84  so as to define a dead air space beneath aperture  52 . If an aperture  52  is located in inner portion  72 , baffle  100  preferably has a lateral wall  104  disposed adjacent inner edge  84  and outer edge  82  of aperture  52  (not shown). Walls  104  may thus effectively define an open central area in particle receiving chamber  50 . 
     Baffles  100 , configured as a wall  102  alone or in conjunction with a lateral wall  104 , reduce and preferably stop the cyclonic nature of the fluid flowing beneath separation member  40 . Referring to FIGS. 14 and 15, baffles  100  may extend from the wall of bin  32  to its centre to effectively divide particle receiving chamber  50  into a plurality of pie-shaped compartments  106  within particle receiving chamber  50 . This configuration substantially inhibits any fluid flow, cyclonic or otherwise, within compartments  106 , thereby beneficially enhancing the anti-reentrainment of characteristics of separation member  40 . 
     Although as described above, it is desirable to position apertures  52  in peripheral portion  70  and/or inner portion  72  of cyclonic flow region  48 , when baffles  100  are used in conjunction with apertures  52  the positioning of apertures  52  is less critical. In such a case, apertures  52  with baffles  100  may be positioned at any location along the radial width of particle separation member  40  and may be disposed in nay one or more of inner portion  72 , medial portion  74  and peripheral portion  70  of cyclonic flow region  48 . 
     The one application as exemplified in FIGS. 16 and 17, the particle separation member may be used with a cyclone separator for a vacuum cleaner. While separator  30  may be used in any vacuum cleaner (eg. upright, canister or a central vacuum cleaning system), it will be described as it may be used in an upright vacuum cleaner. 
     In this application, vacuum cleaner  200  has a floor cleaning head  202 , means for moving cleaning head  202  across a floor (eg. wheels  204 ), main casing  206  rotatably attached to cleaner head  202 , and a handle  208  for moving cleaner  200  across the floor. Main casing  206  houses separator  30 . In this embodiment, a single separator  30  comprises a central air feed conduit  210  in communication with a air nozzle (not shown) adjacent the floor in cleaner head  202 , and leading to a curved air inlet  34 . 
     Referring to FIG. 17, bin  32  is removable from main casing  206 , via the application of pressure by the hand of a user to handle  212 . Bin  32  has an open end  214  and defines a cyclone chamber  46  and particle receiving chamber  50  therein. Separation member  40  has a plurality of apertures  52  disposed in peripheral portion  70  thereof. An air outlet is disposed centrally in an upper portion of cyclone chamber  46 . 
     In use, an air flow is created by a motor (not shown) in vacuum cleaner  200  to draw air from, eg., the nozzle of cleaner head  202 , through centre air feed conduit  210  and into cyclone chamber  46  via inlet  34 . Cyclonic flow is maintained in cyclone chamber  46  thereby causing particles entrained in the cyclonic flow to be deposited, with smaller particles passing through apertures  52  into particle receiving chamber  50 , while larger particles (eg. elongate particles such as hair, carpet fibres and the like) are deposited on upper surface  42 . Air then exits cyclone chamber via air outlet  36 , though the motor and then exits the cleaner. The finer dirt tends to be separated and deposited in particle receiving chamber  50 . 
     Therefore, after operation of vacuum cleaner  200 , particles of varying size may have collected in bin  32  both above and below separation member  40 . To empty such collected contents, bin  32  is removed from main casing  206 , via, eg., handle  212 , and inverted (typically over a refuse collector of the like) to cause the collected particles on upper face  42  to fall from bin  32  under the influence of gravity. 
     If cyclone separator has a closed bottom  90 , then a door or the like is preferably provided to assist in emptying chamber  50 . The door may be provided on the outer wall of bin  32 . Preferably, particle separation member  40  is constructed to assist in emptying the contents of particle receiving chamber  50  when bin  32  is inverted. To this end, particle separation member  40  may be constructed to provide an opening when bin  32  is inverted (see for example FIGS. 17 and 18) or a door may be provided in particle separation member  32  prior to inverting bin  32  (see for example FIGS. 19,  20   a ,  20   b ,  21   a ,  21   b ,  22   a  and  22   b ). 
     Pursuant to the first alternative, separation member  40  may comprise a main body  110  and an access member  112 , as shown in FIG.  18 . Access member  112  comprises a chord section of separation member  40  pivotally connected to main body  110  by a hinge member  114  to swing between a closed position, substantially planar with main body  110  (as 6  represented by the solid lines in FIGS. 17 and 18) and an open position, wherein access member  112  swings upwardly relative to main body  110  (as represented by the broken lines in FIGS.  17  and  18 ). 
     Referring again to FIG. 17, when bin  32  is removed from vacuum cleaner  200  and inverted, access member  112 , by virtue of its pivoting connection to main body  110 , is permitted to freely swings to its “open” position under the influence of gravity, thereby permitting the contents of particle receiving chamber  50  to fall from particle receiving chamber  50  and out of bin  32 . When bin  32  is returned to its upright position, the access member  112  falls to its closed position under the influence of gravity. To bias access member  112  towards its closed positioned when bin  32  is upright, access member  112  may optionally be provided with a weight  116 , or a suitable spring means (not shown) or other biasing means known to those skilled in the art. Hole  118  is provided to permit centre air feed conduit  210  to pass therethrough. 
     The direction of the pivot axis  218  of hinge member  114  is preferably selected to assist access member  112  to remain closed while the vacuum cleaner is in use. If the vacuum cleaner is an upright vacuum cleaner, then particle separation member  40  will be moved from a generally horizontally disposed position when main casing  206  is in the upright storage position to an inclined position when main casing  206  is pivoted to the in use position. Access member  112  has a pivot axis  218  which is preferably not parallel to pivot axis  216  of the upper casing  206  of the vacuum cleaner. In such a case, no weight may be required. Preferably, pivot axis  218  of access member  112  is at an angle β of 10-50°, preferably 20° to 40°, and more preferably about 30° to the pivot axis  216  of upper casing  206  (see FIG.  17 ). 
     Access member  112  is preferably provided in the rear portion of the cyclone bin  32  to prevent access member  112  from opening during use. In particular, all or a major portion of access member  122  is preferably positioned rearward of centre air feed  210  (i.e. towards handle  208 ). In such a case, no weight may be required. 
     In an alternate configuration, referring to FIG. 19 separation member  40  comprises an first member  120  and a second member  122 . First member  120  has a plurality of openings  124 . Second member  122  a plurality of solid members  126  spaced apart by open areas  128 . First and second members  120  and  122  are configured and sized such that, when first member  120  is positioned immediately above second member  122 , first and second members are positionable between a first, “open” position, wherein openings  124  and open areas  128  are substantially aligned (see FIG. 21 a ), and a second, “closed” position, wherein openings  124  and open areas  128  are offset, such that solid members  126  substantially close openings  124  (see FIG. 21 b ). When first member  120  and second member  122  are rotated to the “open” position, openings  124  and open areas  128  provide a plurality of access ports  132  from particle receiving chamber  50  to cyclone chamber  46  (see FIG. 21 a ). 
     Separation member  40  must be provided with apertures  52 . Apertures  52  may be provided as openings in first member  120  such as were discussed with respect to FIG.  1 . Alternately, apertures  52  may be created by constructing members  120  and  122  to leave apertures  52  when they are in the closed position. To this end, solid members  126  may be rotatably so as to only substantially underlie and block openings  124  so as to create a plurality of openings which function as apertures  52  in separation member  40 . Alternately, solid members  126  may have recessed portions  134  provided therein (see FIG. 20 b ) so that when solid member  126  fully underlies openings  124 , a plurality of holes  130  are created (see FIG. 21 b ). 
     In normal operation, first member  120  and second member  122  are in their “closed” position, such that a plurality of apertures  52  are defined in separation member  40 . When in this position, apertures  52  perform a function substantially as described above. To empty the collected contents of bin  32 , and in particular, the contents of particle receiving chamber  50 , bin  32  is removed from main casing  206  of vacuum cleaner  200 , as described above, and first and second members  120  and  122  are moved to their “open” position, thereby opening access ports  132 . The bin is then inverted to empty the collected contents and access ports  132  permit the separated particles in particle receiving chamber  50  to exit into cyclone chamber  46  and out of bin  32 . Thus bin  32  and chamber  50  may be emptied at the same time. First and second members  120  and  122  are then returned to their “closed” position, and the bin returned to main casing  206 , to ready vacuum cleaner  200  for further operation. 
     For convenience, the movement of first and second members  120  and  122  from their “closed” to “open” positions may be automated. This may be achieved by any means known in the art. For example, such movement may be linked to the removal of bin  32  from main casing  206 , such that removal of the bin causes first and second members  120  and  122  to move from their “closed” to “open” positions without further action by the user. In one embodiment, bin  32  is bayonet-mounted (not shown) in main casing  206  such bin  32  must be rotated about its longitudinal axis before bin  32  may be removed from main casing  206 . In response to such rotation, a bayonet-type mechanism (not shown), as is known in the art, triggers a movement of first and second members  120  and  122  from the “closed” to “open” positions, thereby automatically opening separation member  40  in preparation for emptying. For example, member  120  may be affixed to the inner wall of bin  32  and centre air feed  210  may freely rotate within hole  118 . Centre air feed  210  may be rotatably mounted in bin  32  so as not to rotate as bin  32  is rotated for removal and member  122  may be affixed to centre air feed  210 . Thus, as bin  32  is rotated for removal, member  120  rotates with bin  32  relative to member  122  to move separation member  40  to the “open” position. Alternately, a trip-lever mechanism (not shown) may be used such that a horizontal translational movement of bin  32  out of main casing  206  trips a lever which causes first and second members  120  and  122  to move from the “closed” to “open” positions, thereby automatically opening separation member  40  in preparation for emptying. Yet other methods of automatically moving second member  122  upon removal of bin  32  may be devised. 
     It will be understood that first and second members  120  and  122  may be of any configuration which provides “closed” and “open” positions, as described above. For example, first and second members  120  and  122  may be substantially identically shaped (see FIGS. 22 a-b ). It will be understood by one skilled in the art that first member  120  and second member  122  need not move rotationally with respect to one another, but may also move radially or translationally. 
     Although the above description has described the incorporation of the present invention into a household upright vacuum cleaner, it is understood that the present invention can equally be incorporated into a household canister vacuum cleaner, central vacuum system, backpack cleaner, as well as any industrial cyclonic separators. 
     Equally, it will be apparent to one skilled in the art that the separation member according to the present invention may also be employed in the classification and/or sorting of particles by size. Particles to be sorted are entrained in a fluid flow and introduced to a cyclonic separator having a separation member according to the present invention, the separation member having a first aperture size. Particles smaller than the first aperture size are permitted to pass through the separation member and into a hopper for transfer to a subsequent cyclonic separator while larger particles are collected on top of the particle separator. The particle passing through the separation member are introduced cyclonically to a second cyclone having a separation member with apertures of a second, smaller size, relative to the first cyclone. As in the first cyclone, particles smaller than the second aperture size are permitted to pass through the separation member and into a hopper for transfer to a third cyclonic separator, while larger particle remain on the separation member in the second cyclone chamber. This process is repeated, as required, until the particles are classified as needed. 
     The introduction of the separation member according to the present invention to a cyclonic separator dramatically increases the overall efficiency of the separator. The prior art teaches the need for a plurality of cyclones in order achieve ultra-high particle separation efficiencies. However, it has been found that ultra-high efficiencies can be obtained in a single stage cyclone incorporating the particle separation member of the present invention. Cleaning efficiencies in excess of 95% may be obtained with a single stage separator utilizing the separation member according to the present invention, thereby negating the need for second stage cyclonic separation altogether. Cleaning efficiencies of over 99% have also been achieved for particle laden air streams. 
     Therefore, the present invention permits ultra-high efficiencies to be attained with relatively simple separator configurations compared to the prior art. The reduction of separator structure, in turn, beneficially reduces the fluid pressure losses across the separator, thereby permits a deeper vacuum (increased fluid flow rate) to be drawn for a given motor size. For household vacuum cleaner applications, the motor size may be reduced without sacrificing the vacuum strength of the device. The reduced structure and motor size also beneficially result in a cost and size savings to the overall separator unit. 
     The baffle members according to the present invention greatly enhance the performance of the separation member and greatly assist in obtaining ultra-high efficiencies. The projection of baffle members into the particle receiving chamber beneficially disrupts and, depending on the baffle configuration, substantially inhibits cyclonic flow in the particle receiving chamber, thereby reducing the reentrainment of deposited particles. 
     The separation member access means according to the present invention provides a simple and convenient method of emptying collected particles from two chambers simultaneously, namely larger particles deposited in the cyclone chamber (i.e. on top of the particle separation member) and finer particles deposited in the particle receiving chamber. This provides a simple and convenient automatic method of emptying dual chambers. 
     The superimposed particle separation member according to the present invention also provides a convenient method for emptying collected particles from two chambers simultaneously. To enhance the convenience, the movement of the superimposed members may be linked to open when the bin is removed from the main casing. 
     While the above description constitutes the preferred embodiments, it will be appreciated that the present invention is susceptible to modification and change without departing from the fair meaning of the proper scope of the accompanying claims.