Patent Publication Number: US-7588616-B2

Title: Vacuum cleaner with a plate and an openable dirt collection chamber

Description:
This application is a continuation of application Ser. No. 11/019,684 filed on Dec. 23, 2004, now U.S. Pat. No. 7,449,040, which is a continuation of application Ser. No. 10/030,108 filed on Jul. 18, 2002 now U.S. Pat. No. 6,874,197, which is a 371 of serial number PCT/CA00/00873 filed on Jul. 26, 2000 which is a continuation of U.S. patent application Ser. No. 09/482,649 filed on Jan. 13, 2000 now issued as patent number U.S. Pat. No. 6,440,197, which is a continuation in part of application Ser. No. 09/361,128 filed on Jul. 27, 1999 now issued as U.S. Pat. No. 6,228,260, and also application Ser. No. 09/361,124 filed on Jul. 27, 1999 now issued as U.S. Pat. No. 6,221,134. 

   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. In a preferred embodiment, the cyclonic separator is used in a vacuum cleaner to remove entrained particulate matter from an air stream. 
   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 there through, 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 as well as the back pressure caused by the air flow through the cyclones. These latter issues are particularly acute for cyclone separators which are to be contained in a small housing, such as a vacuum cleaner. 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 99.9% efficiency) may be manufactured by positioning in the cyclone chamber a particle separation 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 or apertures in 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. 
   As the fluid flow travels through the cyclone chamber, a boundary layer forms. Generally, the interior surface of a cyclonic chamber is smooth so as to provide for an uninterrupted cyclonic flow in the chamber. However, in the chamber, a boundary layer is still formed on all surfaces over which the fluid passes. According to the instant invention, the system (i.e. the motor means to move the fluid through the chamber, the fluid inlet to the chamber, the fluid outlet to the chamber and/or the construction of the separation member) is designed to minimize the thickness of the boundary layer in the vicinity of the apertures in the separation member. 
   In particular, as the fluid travels over the upper surface of the particle separation member, a boundary flow layer will form. The boundary layer will thicken until a thickness is reached at which the boundary layer has sufficient energy to break off and travel away from the upper surface. Generally at this point, the fluid travels upwardly to the fluid outlet from the cyclone. When the boundary layer breaks off from the upper surface, vortices are formed in the fluid stream adjacent the apertures in the separation member causing localized turbulence. The turbulent flow reentrains particles that had been separated from the fluid flow and may even pull some of the separated particles out of the dead air space beneath the cyclonic flow region of the cyclone chamber. 
   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. 
   In another embodiment of the instant invention, the cyclonic separator is constructed to minimize the thickness of the boundary layer when it breaks off thereby reducing turbulent flow in the vicinity of the apertures. This may be achieved by varying one or more of the number of apertures in the particle separation member, the length of the apertures, the width of the apertures, the included angle between the upstream edge of the apertures and the upper surface of the particle separation member, the included angle between the downstream edge of the apertures and the upper surface of the particle separation member, and the position of a baffle beneath the particle separation member with respect to the point at which the cyclonic air flow changes direction at the bottom of the cyclone chamber. The actual design of the system will changes in the size of the cyclone chamber, the velocity of the fluid flow in the cyclone chamber and the viscosity of the fluid flow in the cyclone chamber. 
   In another embodiment, the flow of the fluid itself may be modified to minimize the thickness of the boundary layer when it breaks off. For example, the fluid flow may be pulsed with the frequency of the pulses set to reduce the maximum thickness of the boundary layer. By pulsing the fluid flow, the fluid flow is cyclically accelerated and decelerated. This cycling is set to encourage the boundary layer to break off when it is thinner than when the fluid flow is not pulsed. The acceleration after the deceleration provides sufficient energy to cause the boundary layer to delaminate sooner than it would in a constant flow regime thereby reducing turbulent flow in the vicinity of the apertures. This pulsed flow may be achieved in several ways such as by sending a pulsed electrical signal to the fluid pump which produces the fluid flow through the cyclone chamber, by pulsing the fluid as it passes through the cyclone air inlet (eg. the inlet may have an aperture that may be cyclically opened and closed at produce the pulsed flow), by pulsing the fluid as it passes through the cyclone air outlet (eg. the outlet may have an aperture that may be cyclically opened and closed at produce the pulsed flow), or by rotating the particle separation member in its plane (eg. by mounting the particle separation member with a spring biasing means so that the particle separation member will cyclically rotate clockwise and then counter clockwise). 
   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. Accordingly, cleaning efficiencies in excess of 99% may be obtained with a single stage separator utilizing a separator according to the present invention, thereby negating the need for second stage cyclonic separation altogether. Cleaning efficiencies of over 99.5% have also been achieved for particle laden air streams. 
   In accordance with this aspect of the instant invention, there is provided a separator for separating entrained particles from a fluid flow, the separator comprising a separator for separating entrained particles from a fluid flow, the separator comprising: 
   (a) a cyclone chamber having an outer wall and a cyclonic flow region; 
   (b) a fluid inlet for introducing a cyclonic fluid flow to the cyclonic flow region; 
   (c) a fluid outlet for removing the fluid flow from the cyclone chamber; 
   (d) a particle separation member positioned in the cyclone chamber beneath at least a portion of the cyclonic flow region, the particle separation member having an upper surface and plurality of apertures; and, 
   (e) a particle receiving chamber disposed beneath the particle separation member for receiving particles passing into the particle receiving chamber through the apertures 
   wherein the separator is constructed to reduce turbulent fluid flow in the vicinity of the apertures. 
   In accordance with the instant invention, there is also provided a separator for separating entrained particles from a fluid flow, the separator comprising: 
   (a) a cyclone chamber for containing a cyclonic flow in a cyclonic flow region; 
   (b) fluid entry means for introducing a fluid flow to the cyclone flow region for cyclonic rotation therein; 
   (c) fluid exit means for removing the fluid flow from the cyclone chamber; 
   (d) fluid pump means for causing fluid flow through the cyclone chamber; 
   (e) particle receiving means disposed beneath the cyclone flow region for receiving particles separated from the fluid flow; 
   (f) separation means for dividing the particle receiving means from the cyclone chamber; 
   (g) 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, a boundary layer flow of fluid develops over the separation means and the particles disentrained from the fluid flow pass through the transporting means to the particle receiving means; and, 
   (h) means for reducing the thickness of the boundary layer of fluid as it travels over the separation means. 
   In one embodiment, the means for reducing the thickness of the boundary layer comprises means for pulsing the fluid flow through the cyclone chamber. The means for pulsing the fluid flow through the cyclone chamber may comprise means for pulsing an electrical signal to the fluid pump means. Alternately, or in addition, the means for pulsing the fluid flow through the cyclone chamber may comprise means pulsing for cyclically opening and closing one of the fluid entry means and the fluid exit means. 
   In another embodiment, the means for reducing the thickness of the boundary layer comprises constructing and positioning the transporting means to reduce turbulent fluid flow over the separation means. 
   In another embodiment, the means for reducing the thickness of the boundary layer comprises constructing and positioning flow disruption means beneath the separating means for disrupting cyclonic fluid flow in the particle receiving means. 
   In another 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 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: 
   (a) introducing a fluid to flow cyclonically in a chamber having a cyclonic flow region and a particle separation member positioned in the cyclone chamber to define a particle receiving chamber; 
   (b) adjusting the back pressure in the chamber to promote the formation of a laminar boundary layer adjacent the particle separation member; 
   (c) removing particles from the fluid flow in the cyclone chamber via passages provided in the particle separation member; and, 
   (d) 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 particle separation member is constructed and positioned to reduce turbulent fluid flow over the particle separation member in the vicinity of the passages and the method further comprises passing the fluid flow over the particle separation member during operation of the chamber. 
   In another embodiment, the chamber further comprises further comprising flow disruption means which is constructed and positioned beneath the separating means for disrupting cyclonic fluid flow in the particle receiving chamber to reduce turbulent fluid flow over the particle separation member in the vicinity of the passages and the method further comprises passing the fluid flow over the particle separation member during operation of the chamber. 
   In accordance with the instant invention, there is also provided a vacuum cleaner comprising: 
   (a) a cyclone chamber having an outer wall and a cyclonic flow region; 
   (b) a fluid inlet for introducing a cyclonic fluid flow to the cyclonic flow region; 
   (c) a cleaner head adapted for movement over a surface and having a fluid nozzle positionable adjacent the surface, the nozzle in fluid flow communication via a passageway with the fluid inlet; 
   (d) a fluid outlet for removing the fluid flow from the cyclone chamber; 
   (e) a particle separation member positioned in the cyclone chamber beneath at least a portion of the cyclonic flow region, the particle separation member having an upper surface and plurality of apertures; and, 
   (f) a particle receiving chamber disposed beneath the particle separation member for receiving particles passing into the particle receiving chamber through the apertures,
         wherein the separator is constructed to reduce turbulent fluid flow in the vicinity of the apertures.       

   In accordance with the instant invention, there is also provided a vacuum cleaner comprising: 
   (a) a cyclone chamber having an outer wall and a cyclonic flow region; 
   (b) a air inlet for introducing a cyclonic air flow to the cyclonic flow region; 
   (c) a cleaner head adapted for movement over a surface and having a air nozzle positionable adjacent the surface, the nozzle in air flow communication via a passageway with the air inlet; 
   (d) a air outlet for removing the air flow from the cyclone chamber; 
   (e) a particle separation member positioned in the cyclone chamber beneath at least a portion of the cyclonic flow region, the particle separation member having an upper surface and plurality of apertures; 
   (f) a particle receiving chamber disposed beneath the particle separation member for receiving particles passing into the particle receiving chamber through the apertures; and, 
   (g) a motor for causing the air to flow through the vacuum cleaner
         wherein the air flow through the cyclone chamber is pulsed.       

   In one embodiment, the vacuum cleaner further comprises a moveable closure member on one of the air inlet and the air outlet for causing a pulsed air flow through the cyclone chamber. 
   In another embodiment, the motor receives an electrical signal and the electrical signal is pulsed to produce the pulsed air flow. 
   In accordance with the instant invention, there is also provided a vacuum cleaner comprising: 
   (a) a cyclone chamber having an outer wall and a cyclonic flow region; 
   (b) a air inlet for introducing a cyclonic air flow to the cyclonic flow region; 
   (c) a cleaner head adapted for movement over a surface and having a air nozzle positionable adjacent the surface, the nozzle in air flow communication via a passageway with the air inlet; 
   (d) a air outlet for removing the air flow from the cyclone chamber; 
   (e) a particle separation member positioned in the cyclone chamber beneath at least a portion of the cyclonic flow region, the particle separation member having an upper surface and plurality of apertures; 
   (f) a particle receiving chamber disposed beneath the particle separation member for receiving particles passing into the particle receiving chamber through the apertures; and, 
   (g) a handle for moving the cleaner head over the floor; and, 
   (h) a motor for causing the air to flow through the vacuum cleaner 
   wherein the particle separation member is constructed and adapted to increase the particle separation efficiency of the cyclone chamber. 
   In one embodiment, the particle separation member has from 5 to 35 apertures. 
   In another embodiment, the number of apertures in the particle separation member is calculated by the formula: 
   
     
       
         
           
             number 
             ⁢ 
             
                 
             
             ⁢ 
             of 
             ⁢ 
             
                 
             
             ⁢ 
             apertures 
           
           = 
           
             
               
                 H 
                 D 
               
               × 
               4 
             
             ± 
             
               20 
               ⁢ 
               % 
             
           
         
       
     
   
   where H=the vertical height of the cyclonic flow region 
   D=the diameter of the cyclone chamber 
   In another embodiment, the cyclone chamber has a diameter and each aperture has a longitudinally extending upstream edge and a longitudinally extending downstream edges, relative to the air flow, and transverse sides extending between the edges, the edges have a length which is less than 10% of the diameter of the cyclone chamber and the sides have a length which is 25-35% of the length of the edges. 
   In another embodiment, the edges are substantially radially aligned with the cyclone chamber. 
   In another embodiment, each aperture has an upstream edge and a downstream edge, relative to the air flow, and the upstream edge is angled towards the particle receiving chamber, the included angle between the upstream edge and the upper surface of the particle separation member is from 15 to 90°. 
   In another embodiment, each aperture has an upstream edge and a downstream edge, relative to the air flow, and the downstream edge is angled towards the particle receiving chamber, the included angle between the downstream edge and the upper surface of the particle separation member is from 15 to 90°. 
   In another embodiment, the air flow changes direction and travels to the air outlet at a position as it travels over the particle separation member and the vacuum cleaner further comprising a baffle positioned beneath the particle separation member at a position 10 to 20° downstream of the position at which the air flow changes direction. 
   In another embodiment, the particle receiving chamber has a bottom to comprise a sealed chamber except for the apertures and the baffle extends between the particle separation member and the bottom of the particle receiving chamber. 

   
     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 a perspective view of a household vacuum cleaner incorporating a cyclone separator according to the present invention; 
       FIG. 2  is a front elevational view of the vacuum cleaner of  FIG. 1 ; 
       FIG. 3  is a side elevational view of the vacuum cleaner of  FIG. 1 ; 
       FIG. 4  is a cross-sectional view along the line  4 - 4  in  FIG. 1 ; 
       FIG. 5  is a cut away perspective view of the cyclonic separation member of  FIG. 1  when removed from the vacuum cleaner; 
       FIG. 6  is a cross-sectional view along the line  6 - 6  in  FIG. 2  with the bin removed; 
       FIG. 7  is a cut away perspective view of an alternate embodiment of the cyclonic separation member of  FIG. 5 ; 
       FIGS. 8 and 9  are cross-sectional views along the line  6 - 6  in  FIG. 2  showing alternate configurations of the particle separation member of the present invention; 
       FIG. 10  is an enlarged cross-section view of the particle separator member of the present invention, showing aperture detail; 
       FIG. 11  is a sectional perspective view of the particle separator member having baffle members according to the present invention; 
       FIG. 12  is an enlarged bottom plan view in the direction of arrow  12  of the baffles of  FIG. 11 ; 
       FIGS. 13-15  are top plan views of various alternate configurations of the particle separation member of the present invention; 
       FIG. 16  is a sectional side view of an alternate embodiment of the particle separator member of the present invention; 
       FIG. 17  is an isometric view of a further alternate embodiment of the particle separator member of the present invention; 
       FIG. 18  is an isometric view of a further alternate embodiment of the particle separator member of the present invention; 
       FIG. 19  is a sectional perspective view of and alternate embodiment of the baffle members according to the present invention; 
       FIG. 20  is a bottom plan view of the baffle members of  FIG. 19 ; 
       FIG. 21  is an enlarged perspective view of the bin of  FIG. 1  when removed from the vacuum cleaner; and, 
       FIG. 22  is an enlarged perspective view of the access member of  FIG. 21 . 
   

   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. 
   For example, 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. 
   In one preferred embodiment, the cyclonic separator is used as a dirt separation means of a vacuum cleaner. As shown in  FIG. 1 , as the cyclonic separator of this invention may have a dirt separation efficiency of 99.95% or higher, the vacuum cleaner may use only a single cyclonic separator and, in fact, the single cyclonic separator of this invention may be the only dirt separation means used in the vacuum cleaner. As is known in the art after filters (i.e. a filter positioned downstream from the motor of the vacuum cleaner) may optionally be provided, eg. a HEPA filter to remove very small quantities of particulate matter such as the carbon dust which is produced by the motor. 
   In the application as exemplified in  FIGS. 1 and 5 , particle separation member  30  is shown as the cyclone separator for vacuum cleaner  200 . While separator  30  may be used in any vacuum cleaner (eg. an upright, a canister, a backpack cleaner or a central vacuum cleaning system), the following discussion describes the use of particle separation member  30  in an upright vacuum cleaner. 
   As exemplified in  FIGS. 1 and 5 , 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  is used and comprises a central air feed conduit  210  in air flow communication with dirty air inlet  220  adjacent the floor in cleaner head  202  (see  FIGS. 4 and 5 ) at one end and in air flow communication with curved air inlet  34  at the other end. Rotatably mounted brush  222  may be positioned in dirty air inlet  220 . 
   Bin  32  may be removable from main casing  206  by any means known in the art (see  FIG. 21 ), such as by the application of pressure by the hand of a user to handle  212 , so that collected dirt may be removed from bin  32 . 
   Cyclonic separator  30  comprises a bin  32  having an open end  214 , 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 . Separation member  40  may be made of plastic plate having a thickness of, eg. 1/40 of the diameter of bin  32 . 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 openings or 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  (see  FIG. 5 ). Particle receiving chamber  50  comprises a chamber extending between lower face  44  and bottom face  90  of bin  32 . Particle receiving chamber  50  preferably comprises about 10% of the volume of bin  32 . 
   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 . The fluid stream is accelerated as it comes into the region of influence of particle separation member  40  which causes the fluid to change direction towards the central portion of cyclonic flow region  48  in cyclone chamber  46  (eg. around central air feed conduit  210 ) and is ultimately removed from cyclone chamber  46  via outlet  36 . As the cyclonic fluid flow moves cyclonically down along inner wall  38  of cyclone chamber  46 , it encounters separation member  40  and travels across separation member  40 . The change in 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 have a greater mass and continue to accelerate towards separation member  40  where (depending on particle size) they pass through apertures  52  into particle receiving chamber  50 . The separated particulate matter collects in particle receiving chamber  50 . 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 . 
   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. 11  particle receiving chamber  50  may be provided with one or more baffles  100 . The baffles operate to reduce and preferably stop the cyclonic flow of air beneath particle separation member  40 . Thus particle receiving chamber  50  forms a dead air space beneath cyclonic flow region  48 . 
   It will thus be appreciated that separation member  40  assists 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. 
   In use, an air flow is created by a motor  224  (eg. the fluid pump means) in vacuum cleaner  200  to draw air from, eg., from dirty air inlet  220 , through passageway  226  in 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  of separation member  40 . Air then exits cyclone chamber via air outlet  36 , though motor  224  and then exits the cleaner via outlet  228 . 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 . 
   In the embodiment of  FIG. 7 , cyclonic separator  30  is used to separate material entrained in an industrial fluid stream. In order to allow the separated material to be collected without interrupting the flow of fluid through cyclonic separator  30 , particle receiving chamber  50  is provided with 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 . Hopper  60  collects separated particles for removal by transport conduit  66  (such as due to gravity flow). 
   It will be appreciated that cyclone chamber  46  may be of any design known in the art. Inner wall need not be cylindrical as shown in  FIG. 1  but may be of any shape known in the art. Further, inlet  34  and outlet  36  may be positioned at any location and more than one inlet and outlet may be used. 
   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. 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. 6 ), inner portion  72  of cyclonic flow region  48  (see  FIG. 8 ), or both peripheral portion  70  and inner portion  72  (see  FIG. 9 ) 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. 6 , cyclone bin  32  having central air feed conduit  210  results in an annular-shaped cyclonic flow region  48 . As a result, cyclonic flow region  48  has a radial width  76  between central air feed conduit  210  and inner wall  38 . However, if there is no member positioned in bin  32  (as shown in  FIGS. 8 and 9 ), then cyclonic flow region  48  has a radial width  76  which extends from central axis A to inner wall  38 . Bin  32  may have a non-circular cross-section (eg. elliptical) or 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 (i.e. in the direction of axis A), 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. 14 ), rectangular (see  FIG. 19 ), triangular, or other regular or irregular shape. Preferably, if apertures  52  are located against the inner or outer edge of separation member  40 , then they have only one wall  57 . For example, as shown in  FIG. 5 , apertures  52  extend all the way to inner wall  38  of bin  32  while in  FIG. 9  they terminate inwardly of inner wall  38 . 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. 11 , upstream and downstream edges  56 ,  58  are preferably longer than the spaced opposed sides  57  extending between edges  56 ,  58  (eg. edges  56 ,  58  are preferably at least twice the length of sides  57 ) so that apertures  52  define slits. 
   As shown in  FIG. 11 , slits  54  may extend generally radially (i.e. edges  56 ,  58  may extend generally radially). However, as shown in  FIG. 13 , slits  54  may be 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 a of slits  54  relative to radial width  76  may be up to 45°. 
   Preferably apertures  52  extend radially and edges  56 ,  58  have a length L which is about 10% or less of diameter D of bin  32  and sides  57  have a length W (i.e. the width of the apertures) which is about 5% or less of diameter D of bin  32  (see  FIG. 11 ). More preferably, length W is about 25 to 35% of length L. 
   Apertures  52  may be equidistantly spaced apart around separation member  40  (see  FIGS. 6-9 ) 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. 6-9 ) or apertures  52  may be positioned around only a portion of separation member  40  (see  FIG. 15 ). 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 . 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. 
   Preferably, particle separation member  40  will have from about 5 to about 35 apertures  52 . The number of apertures  52  which may be required for a particular system may be determined by the formula: 
   
     
       
         
           
             number 
             ⁢ 
             
                 
             
             ⁢ 
             of 
             ⁢ 
             
                 
             
             ⁢ 
             apertures 
           
           = 
           
             
               
                 H 
                 D 
               
               × 
               4 
             
             ± 
             
               20 
               ⁢ 
               % 
             
           
         
       
     
   
   where H=the vertical height of cyclonic flow region  48   
   D=the diameter of bin  32  (see  FIG. 5 ) 
   The formula provides a rough approximation of the ideal number of apertures  52  for a particular system (i.e. within 20%). The actual number of apertures which are required for maximum separation efficiency for a particular system may vary slightly from the formula. 
   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. 16 , 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. 16  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. 17 and 18 , 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. 17 ) or it may be concave (i.e. it may project away from particle receiving chamber  50  as shown in  FIG. 18 ). It will be appreciated that separation member  40  need not define a continuous surface. For example, as shown in  FIG. 18 , it may have a curved surface in which apertures  52  are provided and a flat central top portion  78 . 
   Referring to  FIG. 10 , edges  56  and  58  may be aerodynamically shaped to enhance the performance of separation member  40 . For example, the thickness of particle separation member  40  is preferably reduced adjacent the upstream edge  56 . Referring to  FIG. 10 , aperture  52  has a sloped upstream edge  56  to assist in directing air and particles from cyclone chamber  46  to particle receiving chamber  50 . Upstream edge  56  is preferably sloped with respect to upper surface  42  such that the included angle a′ is from 15 to 90° and an included angle less than 30° is more preferred. The thickness of downstream edge  58  of particle separation member  40  may be substantially unchanged. Alternately, aperture  52  is preferably shaped such that downstream edge  58  is sloped with respect to upper surface  42  to assist in directing air and particles from cyclone chamber  46  to particle receiving chamber  50 . Preferably, the included angle a″ is from 15 to 90° and an included angle less than 30° is more preferred. 
   Preferably, baffles  100  are provided on 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 . 
   As shown in  FIGS. 19 and 20 , 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. 11 and 12 , 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 aperture  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. 19 and 20 , 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 . 
   Preferably, as shown in the embodiment of  FIGS. 2 ,  4 ,  5  and  7 , a single baffle  100  is provided beneath particle separation member  40 . As shown in these embodiments, baffle  100  extends vertically between bottom  90  and lower face  44  and radially outwardly from central air feed conduit  210  to inner wall  38 . In this embodiment, baffle  100  is preferably positioned about 10 to 20° downstream from the point T where the cyclonic flow changes direction to flow upwardly through cyclonic flow region  48  (see  FIGS. 5 and 6 ). 
   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 any one or more of inner portion  72 , medial portion  74  and peripheral portion  70  of cyclonic flow region  48 . 
   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 preferably removable 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. 21 and 22 ) or a door may be provided in bin  32  prior to inverting bin  32 . 
   Pursuant to the first alternative, separation member  40  may comprise a main body  110  and an access member  112 , as shown in  FIG. 22 . 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 represented by the solid lines in  FIGS. 21 and 22 ) and an open position, wherein access member  112  swings upwardly relative to main body  110  (as represented by the broken lines in  FIGS. 21 and 22 ). 
   Referring again to  FIG. 21 , 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 there through. 
   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 in which particle separation member  40  is generally horizontally disposed position when main casing  206  is in the upright storage position (eg. separation member  40  is perpendicular to inner wall  38 ), then particle separation member  40  will be at 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 b of 10-50°, preferably 20° to 40°, and more preferably about 30° to the pivot axis  216  of upper casing  206  (see  FIG. 21 ). 
   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. 
   As the fluid flow travels through bin  32 , a boundary layer forms. A boundary layer is formed on top of particle separation member  40  as the fluid travels over upper surface  42  of particle separation member  40 . The boundary layer will thicken until a thickness is reached at which the boundary layer has sufficient energy to break off and travel away from upper surface  42  (i.e. point T). When this occurs, vortices are formed in the fluid stream adjacent apertures  52  causing localized turbulence. The turbulent flow reentrains particles that had been separated from the fluid flow and may even pull some of the separated particles out of particle receiving chamber  50 . According to the instant invention, separator  30  is preferably constructed to minimize the thickness of the boundary layer when it breaks off thereby reducing turbulent flow in the vicinity of apertures  52 . 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. Accordingly, cleaning efficiencies in excess of 99% may be obtained with a single stage separator utilizing the separator  30  according to the present invention, thereby negating the need for second stage cyclonic separation altogether. Cleaning efficiencies of over 99.5% 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, back pressures of only 4-8 kpa may be obtained allowing the motor size to 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. 
   In another preferred embodiment, the separation efficiency of particle separation member  40  may be increased by pulsing the electrical signal to motor  224 . The timing of the pulses is determined to reduce and preferably minimize the maximum thickness of the boundary layer of fluid as it travels over upper surface  42  in the vicinity of point T. This produces a pulsed fluid flow through bin  32 . Alternately, such a pulsed flow may be mechanically produced such as by providing inlet  34  with an moveable closure member such as plate  120  to which a means is attached to cause the plate to cyclically open and close inlet  34 , eg. a spring, a solenoid  122  having an arm  124  attached to plate  120 , or the like. Alternately, the aperture closure member may be provided on outlet  36 . These mechanical devices effect the back pressure in bin  32  so as to favour smooth (laminar) boundary layer flow as opposed to turbulent flow in the vicinity of apertures  52 . 
   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.