Patent Publication Number: US-2002011050-A1

Title: Suction cleaner with cyclonic dirt separation

Description:
RELATED APPLICATIONS  
     [0001] This application claims the benefit of U.S. Provisional Application 60/201,933, filed May 5, 2000 and U.S. Provisional Application 60/269,044, filed Feb. 15, 2001, all of which are incorporated herein in their entirety. 
    
    
     
       BACKGROUND OF THE INVENTION  
       [0002] 1. Field of the Invention  
       [0003] The invention relates to suction cleaners, and in particular to a separator for a suction cleaner. In one of its aspects, the invention relates to a separator with a cyclonic airflow path to separate dirt and debris from air drawn into the cleaner. In another of its aspects, the invention relates to a separator that deposits the dirt and debris in a collection receptacle. In another of its aspects, the invention relates to a separator including a supplementary fine particle filter.  
       [0004] 2. Description of the Related Art  
       [0005] Dirt separators for suction cleaners, using cyclonic action for separation of dirt from the airflow, are known. U.S. Pat. No. 4,944,780, issued Jul. 31, 1990, to Usmani, discloses a central vacuum system having a cylindrical dirt tank with an interior cylindrical wall adjacent to a tangential inlet. Dirt-laden air drawn into the tangential inlet circulates about the interior of the cylindrical tank to the outside of the interior cylindrical wall. Entrained particulates are separated from the airstream and drop to the bottom of the cylindrical dirt tank. Exhaust air, which may carry smaller particulates, is drawn through a pleated cylindrical filter that is carried on a spindle inside the interior cylindrical wall. Waste air that passes through the filter is drawn through an exhaust opening and is exhausted from the central vacuum cleaner through an exhaust outlet. U.S. Pat. No. 2,943,698, issued Jul. 5, 1968, to Bishop discloses a cylindrical dirt tank having a tangential air inlet, an interior frusto-conical shield, and a cylindrical filter element held in place by a frame comprising a cylindrical wire mesh or perforate screen. After dirt-laden air is introduced into the tank through the inlet, heavier dirt particles fall into a bottom portion of the dirt tank while waste air and any fine particles left in the waste air are exhausted through an air exhaust outlet. The filter element is interposed between the dirt tank and the air exhaust outlet to filter fine particles from the exhaust air.  
       SUMMARY OF THE INVENTION  
       [0006] According to the invention, a vacuum cleaner comprises a housing defining a cyclonic airflow chamber for separating contaminants from a dirt-containing airstream, and a cyclonic chamber inlet and an airstream outlet in fluid communication with the cyclonic airflow chamber. A nozzle base includes a main suction opening fluidly connected with the cyclonic chamber inlet. An airstream suction source is fluidly connected to the main suction opening and to the cyclonic airflow chamber inlet for drawing dirt-containing air from the main suction opening and passing the dirt-containing air to the cyclonic airflow chamber, and selectively establishes and maintains a dirt-containing airstream from the main suction opening to the dirt-containing airstream inlet. A main filter assembly includes a filter element positioned centrally within the cyclonic airflow chamber for filtering residual contaminants from the dirt-containing airstream prior to exit of the airstream from the cyclonic airflow chamber. A dirt-collecting bin is beneath the main filter assembly within the housing, and a separator plate between the filter element and the dirt-collecting bin forms a toroidal chamber within the housing and separates the toroidal chamber from a dirt-collecting chamber.  
       [0007] In a preferred embodiment, the separator plate is mounted to a lower portion of the filter element and extends radially from the filter element toward the housing. The separator plate forms a gap with the housing for passage of dirt particles from the toroidal chamber to the dirt-collecting bin. The gap between the separator plate and the housing is annular, the separator plate being circular and the housing having a circular wall adjacent the separator plate.  
       [0008] In a preferred embodiment, the cyclonic chamber inlet is in the toroidal chamber.  
       [0009] In a further embodiment, the airstream outlet is in an upper central portion of the housing.  
       [0010] In a further embodiment, a secondary filter positioned between the filter element and the airstream outlet.  
       [0011] In a further embodiment, the secondary filter comprises a fine mesh.  
       [0012] In a further embodiment, the airstream outlet is in a lower portion of the housing.  
       [0013] In a further embodiment, the relative cross-sectional area of the separator plate with respect to the housing is in the range of 0.75 to 0.95.  
       [0014] In a further embodiment, the relative cross-sectional area of the separator plate with respect to the housing is in the range of 0.8 to 0.92.  
       [0015] In a further embodiment, the relative cross-sectional area of the separator plate with respect to the housing is about 0.9.  
       [0016] In a further embodiment according to the invention, a vacuum cleaner comprises a housing defining a first cyclonic airflow chamber for separating contaminants from a dirt-containing airstream, said housing further comprising an airstream inlet and an airstream outlet in fluid communication with said first cyclonic airflow chamber, a nozzle base including a main suction opening fluidly connected with said first cyclonic airflow chamber inlet, and an airstream suction source fluidly connected to the main suction opening and to the first cyclonic airflow chamber inlet for drawing the dirt-containing airstream from the main suction opening and passing the dirt-containing airstream to the first cyclonic airflow chamber. The suction source selectively establishes and maintains the dirt-containing airstream from the main suction opening to said first cyclonic airflow chamber. A second cyclonic airflow chamber is formed coaxially with the first cyclonic airflow chamber. A main filter assembly including a filter element is positioned between the first and second cyclonic airflow chambers for filtering residual contaminants from the dirt-containing airstream prior to exit of the airstream from the first cyclonic airflow chamber. A first dirt-collecting bin is beneath the first cyclonic airflow chamber and a second dirt-collecting bin in communication with the second cyclonic air flow chamber is positioned axially of the first dirt-collecting bin.  
       [0017] In a further embodiment, a frusto-conical wall defines the second cyclonic airflow chamber and a wall of the second dirt-collecting bin.  
       [0018] In a further embodiment, the second dirt-collecting bin is positioned axially above the first dirt-collecting bin.  
       [0019] In a further embodiment, the airstream outlet is positioned in a lower portion of the housing. The airstream outlet is positioned concentrically with respect to the second cyclonic airflow chamber.  
       [0020] In a further embodiment, the filter element is a foraminous wall.  
       [0021] In a further embodiment, a separator plate is positioned between the first cyclonic airflow chamber and the first dirt-collecting bin. The relative cross-sectional area of the separator plate with respect to the housing is in the range of 0.75 to 0.95.  
       [0022] In a further embodiment, at least one vane is positioned between the first and second cyclonic airflow chambers for imparting a tangential velocity component to the airflow.  
       [0023] In a further embodiment according to the invention, a vacuum cleaner comprises a housing defining a cyclonic airflow chamber for separating contaminants from a dirt-containing airstream, and an airstream inlet and an airstream outlet in fluid communication with the cyclonic airflow chamber. A nozzle base includes a main suction opening fluidly connected with the cyclonic airflow chamber inlet. An airstream suction source is fluidly connected to the main suction opening and to the cyclonic airflow chamber inlet for drawing the dirt-containing airstream from the main suction opening and passing the dirt-containing airstream to the cyclonic airflow chamber. The main suction source selectively establishes and maintains the dirt-containing airstream from the main suction opening to the cyclonic airflow chamber inlet. A main filter assembly includes a filter element for filtering residual contaminants from the suction airstream. A dirt-collecting bin is beneath the cyclonic airflow chamber within the housing. The cyclonic airflow chamber is formed by a tangential helical ramp.  
       [0024] In a further embodiment, the main filter assembly is concentric with cyclonic airflow chamber.  
       [0025] In a further embodiment, there is an opening from the cyclonic airflow chamber into the dirt-collecting bin and an opening from the dirt-collecting bin into the main filter assembly whereby the airstream changes direction to enter the main filter assembly.  
       [0026] In a further embodiment, the airstream outlet is centrally located within the housing. The airstream outlet passes through the dirt-collecting bin. 
     
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
     [0027] In the drawings:  
     [0028]FIG. 1 is a front view of a suction cleaner housing with cyclonic dirt separation according to the invention.  
     [0029]FIG. 2 is a side view of the suction cleaner of FIG. 1.  
     [0030]FIG. 3 is a rear view of the suction cleaner of FIGS.  1 - 2 .  
     [0031]FIG. 4 is an exploded perspective view of a dirt collection assembly of the suction cleaner of FIGS.  1 - 3 .  
     [0032]FIG. 5 is an exploded perspective view of an upper housing and a motor housing of the suction cleaner of FIGS.  1 - 3 .  
     [0033]FIG. 6 is a front view of a cylindrical separator of the suction cleaner of FIGS.  1 - 5 .  
     [0034]FIG. 7 is a cross-sectional view through line  7 - 7  of FIG. 6.  
     [0035]FIG. 8 is a cross-sectional view taken through line  8 - 8  of FIG. 2.  
     [0036]FIG. 9 is a cross-sectional view taken through line  9 - 9  of FIG. 2.  
     [0037]FIG. 10 is a cut-away perspective view of the suction cleaner of FIGS.  1 - 9  showing air flow around the cylindrical separator in the dirt collection assembly.  
     [0038]FIG. 11 is a cut-away perspective view of the cylindrical separator of FIGS.  1 - 10  showing an internal axial air flow.  
     [0039]FIG. 12 is a cut-away perspective view of a further embodiment of a cyclonic separator for a suction cleaner according to the invention.  
     [0040]FIG. 13 is a front cross-sectional view of the cyclonic separator of FIG. 12.  
     [0041]FIG. 13A is a front cross-sectional view of a further embodiment of a cyclonic separator according to the invention.  
     [0042]FIG. 14 is a cross-sectional view taken through line  14 - 14  of FIG. 13.  
     [0043]FIG. 15 is a cut-away perspective view of a further embodiment of a dirt collection assembly with cyclonic dirt separation according to the invention.  
     [0044]FIG. 16 is an exploded perspective view of another embodiment of a dirt collection assembly with cyclonic dirt separation according to the invention.  
     [0045]FIG. 17 is an enlarged perspective view of a filter assembly for the dirt collection assembly of FIG. 16.  
     [0046]FIG. 18 is an enlarged perspective view of a cyclonic separator of the dirt collection assembly of FIG. 16.  
     [0047]FIG. 19 is a plan view of the dirt collection assembly of FIG. 16.  
     [0048]FIG. 20 is a cross-sectional view of the dirt collection assembly taken through line  20 - 20  of FIG. 19. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
     [0049] With reference to FIGS.  1 - 3 , a suction cleaner with cyclonic dirt separation  10  comprises an upper housing  12 , a motor housing  14 , and a dirt collection assembly  16 . The upper housing  12  includes a two-piece handle  18 , an upper cord wrap  20 , and an air inlet  22 . The upper housing  12  further includes first and second switches  36 ,  38 . The motor housing  14  includes a lower cord wrap  24 , an exhaust air vent  26  and a floor suction conduit  28 . The dirt collection assembly  16  comprises a dirt tank  30 , a tank cap  32 , and a tank latch  34 . Each of the dirt collection assembly  16 , upper housing  12 , and motor housing  14  are configured to be assembled to present a smooth, continuous appearance, and to be generally fluid-tight.  
     [0050] The dirt collection assembly  16 , as shown in FIG. 4, includes the dirt tank  30 , the tank cap  32  and the tank latch  34 , and further includes a cylindrical separator  40 , a secondary filter cup  120 , a gasket  58 , a separator plate  42 , a cylindrical preliminary filter  44 , and a top plate  46 . Dirt tank  30  includes an air inlet aperture  31 . Tank cap  32  includes tank latch recess  33  for receiving tank latch  34 . Tank latch  34  is an integral molding including a body portion  96 , two generally downwardly depending leaf springs  98 , and two rearwardly extending catches  100 . Cylindrical separator  40  is a hollow cylinder and includes in its interior radially inwardly projecting ribs  110 , and on its exterior twist-and-lock grooves  86 . Secondary filter cup  120  includes an upper rim  122 , cylindrical side wall  124 , and bottom wall  126 . Gasket  58  is annular and resilient for forming a compressive seal. Separator plate  42  is substantially annular, having an outer perimeter flange  88 , and further including an inner portion having upwardly extending separator plate radial ribs  92  joined at a central hub and defining a central cavity  56 , and separator plate apertures  94  defined radially between radial ribs  92 . Separator plate  42  further includes filter alignment slots  85  adjacent radial ribs  92 . Separator plate  42  further includes a depending skirt  95 , skirt  95  having inwardly projecting tabs  84  for receipt in twist-and-lock grooves  86 . Preliminary filter  44  includes a filter element  48  in the form of a fine mesh screen, and upper and lower filter frames  50 ,  51 . Lower filter frame  51  includes alignment tabs  53  for receipt in alignment slots  85  of separator plate  42 . Top plate  46  includes upwardly projecting studs  52  and a downwardly projecting frusto-conical portion  54 . Filter element  48  has been found to be effective with a fine mesh having openings as small as 40 microns.  
     [0051] Referring now to FIGS.  6 - 7 , ribs  110  of separator  40  each having an upper end  112  slightly recessed from the upper end of separator  40 . Separator  40  receives cup  120  so that ribs  110  support rim  122 , suspending cup  120  within separator  40 , rim  122  being substantially flush with the upper end of separator  40 . Separator plate  42 , with gasket  58 , is then received on separator  40  in a twist-and-lock arrangement using tabs  84  and grooves  86 , creating a sealing arrangement between plate  42  and separator  40 , and holding cup  120  in place against ribs  110 . Prior to placement of plate  42  on separator  40 , preliminary filter  44  is aligned on separator plate  42  using tabs and slots  53 ,  85 , coaxial with cylindrical separator  40 . Frusto-conical section  54  is configured to fill central cavity  56  formed in the separator plate  42  to sandwich preliminary filter  44  therebetween. Preliminary filter  44  is thereby sealingly received between the top plate  46  and the separator plate  42  when the frusto-conical section  54  of the top plate  46  is received in the central cavity  56  of the separator plate  42 . The pins  52  projecting from the top plate  46  are received in recesses (not shown) on the underside of the tank cap  32  for holding and aligning the top plate  46  to the tank cap  32 .  
     [0052] Referring again to FIG. 4, and to FIG. 9, the dirt collection assembly  16  comprises dirt tank  30  having a generally cylindrical interior, and having a central aperture  76  on the bottom thereof. The cylindrical separator  40  is coaxially received within the dirt tank  30 , so that the open end of the hollow cylindrical separator  40  is aligned with and sealingly engages the perimeter of the central aperture  76  of the dirt tank  30 . The cylindrical separator  40  is preferably affixed to tank  30  at central aperture  76 , such as by welding. The assembly comprising the tank cap  32 , top plate  46 , preliminary filter  44 , and separator plate  42  are received within the upper end of dirt tank  30  as separator plate  42  is received on the cylindrical separator  40  in the twist-and-lock arrangement of tabs and grooves  84 ,  86 . The perimeter of the top plate  46  includes a canted lip  82  configured to fit inside the upper edge of the tank  30  in a sealing fit. The top plate  46  is fixed within the tank cap  32 , so that when the top plate is fit within the top of the dirt tank  30 , the exterior of the tank cap  32  aligns with the exterior of the dirt tank  30  to provide a uniform flush surface. The separator plate  42  includes a perimeter flange  88  having a diameter less than the interior diameter of the dirt tank  30 , resulting in an annular gap  90  between the separator plate  42  and the side walls of the dirt tank  30 .  
     [0053] The motor housing  14  having exhaust air vent  26 , shown in FIG. 5, further comprises a motor cage  60  having exhaust vents  68 , a motor/impeller assembly  62 , an impeller gasket  64  and a motor cover  66 . Motor/impeller assembly  62  includes motor brushes  63 , impeller intake  65 , and motor electrical connections (not shown). Motor/impeller assembly  62  is closely received within motor cage  60 , motor cage  60  further comprising integral ribs (not shown) that cooperate with the exterior of motor/impeller assembly  62  in a nesting relationship. Motor cover  66  includes a raised intake port  70  having apertures  72 . Gasket  64  is configured to create a fluid seal between motor cover  66  and motor/impeller assembly  62  so that impeller intake  65  is in sealed fluid communication with intake port  70 . Motor cage  60  and motor cover  66  are configured to enclose motor/impeller assembly  62  and gasket  64 , providing sealed fluid communication between the motor cover  66  and exhaust vents  68 , through motor/impeller assembly  62 . Motor housing  14  is configured to mate with the bottom of the upper housing  12  so that the motor cover  66  sealingly fills central aperture  74 , and the bottom of the upper housing  12  sealingly covers the motor housing  14 . Assembly of the motor cage  60  within the motor housing  14 , and further assembly of the motor housing  14  to the upper housing  12 , therefore creates a sealed fluid path between the interior of the upper housing  12  at apertures  72  of the motor cover  66 , to exhaust outlet  26  of motor housing  14 , through motor/impeller assembly  62 .  
     [0054] Referring now to FIGS.  8 - 11 , the dirt collection assembly  16  can be assembled and inserted into the upper housing  12  so that the cylindrical separator  40  within the tank  30  is aligned with and fluidly connected with the motor cover  66 , and the inlet aperture  31  of the dirt tank  30  is further fluidly connected with the air inlet  22 , as particularly shown in FIGS. 8 and 10. Dirt collection assembly  16  is held in upper housing  12  by tank latch  34  as will be further described below. The air inlet  22  is therefore fluidly connected to the exhaust air vent  26  of the motor housing  14  through the aperture  31  of the dirt tank  30 , the preliminary filter element  44 , the separator plate  42 , the hollow cylindrical separator  40 , the apertures  72  of the raised portion  70  of the motor cover  66 , the motor impeller assembly  62 , and the exhaust vent  68  of the motor cage  60 .  
     [0055] The user controls the suction cleaner by activating one of the switches  36 ,  38  to supply power to the motor impeller assembly  62 . When the motor impeller assembly  62  is activated, a suction force is generated at the motor cover  66 , causing a flow of air from the motor cover  66  through the motor impeller assembly  62 , motor cage  60  and into the motor housing  14 , and then to atmosphere through the exhaust air vent  26 . A post-motor filter (not shown) is configured to fully occupy, and is inserted in, the space between exhaust vents  68  and exhaust air vent  26 . When the motor cover  66  is sealingly and fluidly connected to the cylindrical separator  30 , as in when the dirt collection assembly  16  is fully installed in the upper housing  12 , the suction force is fluidly connected through the cylindrical separator  30 , separator plate  42 , preliminary filter  44  and aperture  31  to the air inlet  22 . A suction hose or nozzle of known construction is generally attached to the air inlet  22  for use in cleaning a surface.  
     [0056] As air is drawn into the air inlet  22 , the air inlet  22  imparts a tangential component to the inlet air, as shown in FIG. 10, as it enters the dirt tank  30  through the aperture  31 . The air enters the dirt tank  30  in a toroidal section of the dirt tank formed between top plate  46  and separator plate  42 , and between the preliminary filter  44  and the interior tank wall. As the air flows in a tangential direction about the dirt tank  30 , heavier particles of dirt and debris are propelled outwardly by centrifugal force and fall under the force of gravity through the gap  90  formed between the perimeter flange  88  of the separator plate  42  and the dirt tank  30  into the lower portion of the dirt tank  30 . It has been found that separator plate  42  acts as a separator between two air velocity zones, one existing in the toroidal chamber  80  having a relatively high rotational air velocity, and a second zone separated from the toroidal chamber  80 , below separator plate  42 , having a much lower rotational air velocity. The high rotational air velocity in the toroidal chamber  80  forces dirt particles contained in the airstream to the outside of the chamber where they will be drawn through the gap  90  to the outside of flange  88 . As the airstream flows into the zone beneath the separator plate  42  and the air velocity decreases, the dirt particles will fall out of the airstream and collect and the dirt tank  30 . It has been found that narrowing the gap  90 , in the sense of having a high ratio of the surface area of the plate  42  to the overall cross-sectional area of the housing, is beneficial to maintaining the two air velocity zones. This must be balanced with maintaining a gap  90  large enough to enable passage of larger dirt particles such as hair, carpet fuzz, etc. A relative plate surface area in the range of 0.75 to 0.95 with respect to the housing cross-sectional area is effective in defining the two air velocity zones while enabling the passage of large dirt particles, with the preferred ratio of surface areas being 0.8 to 0.92, or optimally 0.9.  
     [0057] The air flow circulates tangentially about the interior of the tank  30  until it is drawn inwardly toward the preliminary filter element  44 , as shown in FIG. 11. As the air flow passes through the preliminary filter element  44 , the filter element  44  prevents larger dirt particles and debris, that did not fall to the lower portion of the dirt tank  30 , from passing into the interior of filter element  44  and then into the interior of separator  40  and filter cup  120 . The air is then drawn downwardly between separator plate radials  92  through separator plate apertures  94  (see FIG. 8), through filter cup  120  which traps additional finer particles, and passes axially through the hollow interior of the cylindrical separator  40 , then through apertures  72  and the motor housing  14  to atmosphere through the post motor filter (not shown) and the exhaust air vent  26 .  
     [0058] Dirt and debris, when collected in the dirt tank  30 , can be discarded by removing the dirt collection assembly  16  from the upper housing  12 . Dirt collection assembly  16  is retained in upper housing  12 , as stated above, by tank latch  34  on tank cap  32 . Leaf springs  98  bias latch  34  upwardly by pressing against the bottom of recess  33 , forcing the catches  100  underneath a lip  35  of the handle  18 , thereby retaining the tank cap  32  against the handle  18 . Latch  34  is released by depressing the latch body  96  against the biasing force of the leaf springs  98 , thereby releasing the catches  100  from the lip  35 . The dirt collection assembly  16  can then be tilted away from the housing portion  12 . With the dirt collection assembly  16  removed from the upper housing  12 , the assembly comprising tank cap  32 , top plate  46 , preliminary filter  44  and separator plate  42 , can be removed from dirt tank  30  and cylindrical separator  40  as a unit by counter-clockwise rotation of the twist-and-lock arrangement of tabs and grooves  84 ,  86 . The upper portion of the dirt tank  30  and the filter cup  120  are thus open so that they can be emptied by a user. Filter cup  120  can further be removed from separator  40  for cleaning, and top plate  46  can be further separated from the separator plate  42  for cleaning or replacement of the preliminary filter assembly  44 . Upon reassembly as described above, dirt collection assembly  16  is replaced in upper housing  12  by inserting the lower portion of the assembly  16  into the housing portion  12  and tilting it inwardly until catches  100  resiliently slide past lip  35  to bias upwardly and engage lip  35  and hold assembly  16  in place in upper housing  12 .  
     [0059] Referring to FIG. 12, a further embodiment of a cyclonic dirt separator  140  according to the invention comprises a cylindrical cyclone chamber  150  having an upper wall  142  and a sidewall  144 , the sidewall  144  terminating in a lower offset lip  146 . An annular collar  148  depends from upper wall  142 , the collar  148  being centered in the cylindrical chamber  150 . An exhaust outlet  154  in the upper wall  142  and within the annular collar  148  is fluidly connected with a suction source (see FIG. 14). Sidewall  144  further includes a tangential air inlet  152  aligned proximate the upper wall  142  for generating a tangential airflow in the chamber  150  parallel to the upper wall  142 .  
     [0060] The cyclonic dirt separator  140  further comprises a primary filter element  168 . In a preferred embodiment, the primary filter element  168  comprises a cylindrical fine mesh screen  170  retained by the collar  148  that depends from upper wall  142  of the chamber  150 . Cyclonic dirt separator  140  further comprises a separator plate  158  in the form of a solid disc having an upstanding annular collar  164 . In the preferred embodiment, the upstanding annular collar  164  is aligned with the depending collar  148  of the upper wall  142  so that the cylindrical screen  170  is retained at the ends thereof by each of the collars  148 ,  164 . In this manner, separator plate  158  is suspended from upper wall  142 , forming a toroidal chamber  180  between the cylindrical screen  170  and the sidewall  144 , and between the upper wall  142  and the separator plate  158 , respectively. In the preferred embodiment, air inlet  152  is vertically aligned between upper wall  142  and separator plate  158  such that the tangential airflow generated from tangential air inlet  152  is directed into the toroidal chamber  180 .  
     [0061] With further reference to FIGS.  13 - 14 , the tangential airflow, containing particulate matter, passes through tangential air inlet  152  and into toroidal chamber  180  to travel around the cylindrical screen  170 . As the air travels about the toroidal chamber  180 , heavier dirt particles are forced toward sidewall  144 . These particles will fall under the force of gravity through a gap  166  defined between an edge  162  of separator plate  158  and the sidewall  144 . Referring particularly to FIG. 13, dirt particles falling through the gap  166  drop through the open end  156  of chamber  150  and are collected in the dirt cup  160 . The upper end of dirt cup  160  is received in a nesting relationship in lower offset lip  146  of the sidewall  144  to seal the cyclone chamber  150  to the dirt cup  160 .  
     [0062] As the inlet air traverses through toroidal chamber  180 , casting dirt particles toward sidewall  144 , the inlet air will be drawn through cylindrical screen  170 , through exhaust outlet  154 , exhaust/suction conduit  196 , through a secondary (pre-motor) filter  192  to the suction source  190 . The secondary filter  192  removes additional particulate matter from the exhaust airstreams prior to the airstreams being drawn through the suction source  190 . A post-motor filter  194  can also be provided downstream of the suction source  190  to remove additional fine particulate matter from the exhaust airstream before it is released to the atmosphere.  
     [0063] Dirt cup  160  is removably connected to chamber  150 . Accumulated dirt can be discarded by axially displacing dirt cup  160  from cyclone chamber  150  so that it disengages from offset lip  146 . Dirt cup  160  can then be removed from chamber  150  to discard accumulated dirt.  
     [0064] A further embodiment of a cyclonic separator  440  is shown in FIG. 13A. the cyclonic separator  440  comprises a cylindrical cyclone chamber  450  having an upper wall  442  and a sidewall  444 , the sidewall  444  terminating in a lower offset lip  446 . A substantially cylindrical filter assembly  468  depends from upper wall  442 , being centered in the cylindrical chamber  450 . An exhaust outlet  454  in the upper wall  442  and within the filter assembly  468  is fluidly connected with a suction source  490 . Sidewall  444  firther includes a tangential air inlet  452  aligned proximate the upper wall  442  for generating a tangential airflow in the chamber  450  parallel to the upper wall  442 .  
     [0065] In a preferred embodiment, the filter assembly  468  comprises a plurality of apertures  470  passing through the wall of the assembly  468  and fluidly connecting air inlet  452  with exhaust outlet  454 . Cyclonic dirt separator  440  further comprises a separator plate  458  in the form of a solid disc. Separator plate  458  is secured by fasteners  472  to a lower end of cylindrical filter assembly  468 , parallel to upper wall  442 , forming a toroidal chamber  480  between the cylindrical filter assembly  468  and the sidewall  444 , and between the upper wall  442  and the separator plate  458 , respectively. In the preferred embodiment, air inlet  452  is vertically aligned between upper wall  442  and separator plate  458  such that the tangential airflow generated from tangential air inlet  452  is directed into the toroidal chamber  480 .  
     [0066] As in the previous embodiment, the tangential airflow, containing particulate matter, passes through tangential air inlet  452  and into toroidal chamber  480  to travel around the cylindrical filter assembly  468 . As the air travels about the toroidal chamber  480 , heavier dirt particles are forced toward sidewall  444 . These particles will fall under the force of gravity through a gap  466  defined between an edge  462  of separator plate  458  and the sidewall  444 . Dirt particles falling through the gap  466  drop through the open end  456  of chamber  450  and are collected in the dirt cup  460 . The upper end of dirt cup  460  is received in a nesting relationship in lower offset lip  446  of the sidewall  444  to seal the cyclone chamber  450  to the dirt cup  460 .  
     [0067] As the inlet air traverses through toroidal chamber  480 , casting dirt particles toward sidewall  444 , the inlet air will be drawn through the apertures  470  in cylindrical filter assembly  468 , through exhaust outlet  454 , exhaust/suction conduit  496 , through a secondary (pre-motor) filter  492  to the suction source  490 . The secondary filter  492  removes additional particulate matter from the exhaust airstreams prior to the airstreams being drawn through the suction source  490 . A post-motor filter  494  can also be provided downstream of the suction source  490  to remove additional fine particulate matter from the exhaust airstream before it is released to the atmosphere.  
     [0068] Dirt cup  460  is removably connected to chamber  450 . Accumulated dirt can be discarded by axially displacing dirt cup  460  from cyclone chamber  450  so that it disengages from offset lip  446 . Dirt cup  460  can then be removed from chamber  450  to discard accumulated dirt.  
     [0069] A further embodiment of a cyclonic separator  300  is depicted in FIG. 15. The cyclonic separator  300  comprises a dirt bin  310  having a cylindrical configuration with an exterior wall  312 , a bottom wall  314  having a central opening  316  integral with a hollow cylindrical shaft  318  extending from bottom wall  314 . Shaft  318  includes an upper end  320  and extends coaxially within bin  310  so that upper end  320  extends above an upper end  322  of exterior wall  312  of dirt bin  310 . Dirt bin  310  firther comprises a tangential inlet opening  324  passing through the exterior wall  312  of the dirt bin  310 , located proximate the upper end  322  of the exterior wall  312  of the dirt bin  310 .  
     [0070] The cyclonic separator  300  further comprises a cyclonic insert  330  having a substantially hollow cylindrical body  332 , cylindrical body  332  shown as having a neck portion  334  in a central area thereof, so that the diameter of the cylindrical body  332  is slightly narrower at neck portion  334 . Cylindrical body  332  is further contemplated as being uniform in diameter, i.e. eliminating neck portion  334 . Cyclonic insert  330  further comprises an annular bottom portion  336 .  
     [0071] Annular bottom portion  336  includes a central opening  338  configured to closely conform to the exterior of the central shaft  318  of the dirt bin  310 . Bottom portion  336  is connected to the exterior wall of the cylindrical portion  332  of the cyclonic insert  330 , and further includes a separator flange  340 . Separator flange  340  extends downwardly at an obtuse angle beyond the exterior wall of the cylindrical body  332 .  
     [0072] The cylindrical body  332  of the cyclonic insert  330  has a diameter less than the diameter of the cylindrical dirt bin  310 , so that when the cyclonic insert  330  is inserted into the dirt bin  310 , a toroidal portion  342  is formed therebetween. The separator flange  340  does not extend to cylindrical wall  312 , leaving a gap  344  between the separator flange  340  and the interior of the cylindrical wall  312  of the dirt bin  310 .  
     [0073] The interior of the dirt bin  310  is thus divided into two toroidal portions  342 ,  346 , the first toroidal portion  342  being between the cyclonic insert  330  and the wall  312  of the dirt bin  310 , and the second toroidal portion  346  formed between the central shaft  318  and the cylindrical wall  312  of the dirt bin  310 , beneath the separator flange  340 .  
     [0074] The cyclonic insert  330  further comprises an upper annular flange portion  348  integrally formed with the cylindrical body  332  of the cyclonic insert  330 , the flange portion  348  having an outer diameter equivalent to the outer diameter of the dirt bin  310  and configured to be received in an engaging and sealing manner on the upper edge  322  of the exterior wall  312  of the dirt bin  310 .  
     [0075] The cylindrical body  332  of the cyclonic insert  330  further comprises two wall portions, an impervious upper wall portion  352  and a lower wall portion  354  having a plurality of perforations  356  passing therethrough. Perforations  356  are contemplated as being of uniform size and spacing, or of being arranged in a non-uniform pattern of varying apertures, as required to develop the most advantageous airflow pattern.  
     [0076] The cyclonic insert  330  further includes a plurality of canted vanes  358  arranged in a ring about the interior of the cyclonic insert  330  at the necked portion  334  of the cylindrical body  332 . The vanes  358  include a central opening  360  configured to closely receive the central shaft  318  of the dirt bin  310 .  
     [0077] The necked portion  334 , and the vanes  358 , substantially divide the volume between the cyclonic insert  330  and the central shaft  318  of the dirt bin  310  into two toroidal portions  362 ,  364 . The first toroidal portion  362  is bounded on its interior by the central shaft  318  of the dirt bin  310 , and on its exterior by the perforated section  354  of the cylindrical portion of the dirt bin  310 . The second toroidal portion  364  is bounded on its interior by the central shaft  318  of the dirt bin  310  and on its exterior by the solid portion  352  of the cylindrical portion of the cyclonic insert  330 . the second toroidal portion  364  is bounded at its lower end by the vanes  358  and at its upper end by a frusto-conical chamber  368  defined by a frusto-conical wall  376 .  
     [0078] The cyclonic separator  300  further comprises a secondary cyclone chamber  370 , the chamber  370  comprising an outer cylindrical wall  372 , a lower annular wall  374  and frusto-conical wall  376 . The bottom wall  374  of the chamber  370  has an annular perimeter  378  for abutting the perimeter edge  350  of the cyclone insert  330  to present a flush appearance and to resist removal of the chamber  370  from the insert  330 .  
     [0079] The chamber  370  further comprises a chamber cap  380 , being a disk having a depending rim  382  for receipt in an upper portion  384  of the cylindrical chamber  370  in a sealing manner. The exterior wall  372 , lower wall  374  and frusto-conical wall  376  of the chamber  370  are integrally formed, forming a substantially toroidal receptacle  386 . The frusto-conical wall  376  is shorter than the exterior walls  372  of the chamber  370  resulting in a gap  388  between a top edge  390  of the hollow frusto-conical wall  376  and the lid  380  of the chamber  370 .  
     [0080] Prior to assembly, therefore, the cyclonic separator  300  comprises a cylindrical dirt bin  310  having a concentric cylindrical shaft  314  passing from an aperture  316  and a flat bottom  314  to above the upper edge  322  of the dirt bin  310 , forming a single toroidal chamber therebetween. Inserting the cyclonic insert  330  in a sealing engagement with the upper edge  322  of the dirt bin  310  divides the interior of the dirt bin  310  into two toroidal portion  342 ,  346  to the outside of the insert  330 . The toroidal portions  342 ,  346  are separated by the separator flange  340  of the cyclonic insert  330 , except for a gap  344  between separator flange  340  and wall  312 .  
     [0081] The interior of the insert  330  is divided into toroidal sections  362 ,  364  inside the cylindrical body  332  of the insert  330 . The toroidal sections  362 ,  364  are defined by the vanes  358 . The central shaft  318  still projects above the top  322  of the bin  310  and the upper flange  348  of the cyclonic insert  330 .  
     [0082] Attaching the secondary cyclone chamber  370  and its lid  380  places the upper end  320  of the central shaft  318  within the hollow frusto-conical wall  376  of the secondary cyclone chamber  370 . The cyclonic separator  300  is now sealed from the atmosphere except for the tangential inlet  324  of the dirt bin  310  and the central outlet  316  at the base  314  of the dirt bin  310 . The tangential inlet  324  and outlet  316  are fluidly connected through the dirt bin  310 , perforations  356  of the cyclonic insert  330 , through the toroidal sections  362 ,  364  within the cyclonic insert  330  and through the upper end  320  of the central shaft  318 .  
     [0083] The cyclonic separator, when used in a suction cleaner, will have a vacuum source fluidly connected to the outlet opening  316 , thereby forming a vacuum within the cyclonic separator  300  and at the tangential inlet  324  to the dirt bin  310 . Inlet  324  will be fluidly connected to a surface cleaning apparatus. Dirt-laden air will be drawn through the inlet  324  into the first toroidal section  342 , the air flow having a tangential component due to the orientation of inlet  324 . As the dirt-laden air is circulated about the perimeter of the dirt bin  310 , the dirt will be driven toward the outer wall  312  of dirt bin  310  and tend to fall towards the bottom wall  314  to the outside of the separator flange  340 .  
     [0084] As the air circulates about dirt bin  310 , the air will be drawn inwardly toward the perforations  356  in the lower portion  354  of the cylindrical portion  332  of the cyclonic insert  330 . Heavier particles of dirt will fall to the bottom of the dirt bin. The separator flange  340  acts to discourage dirt particles from being recirculated in the air flow adjacent the perforations  356 .  
     [0085] The air passing through the perforations  356  continues to carry finer particulates that were not heavy enough to be deposited in the bottom of the dirt bin  310 . The perforations  356  substantially pass perpendicularly through the surface  354  of the cyclonic insert  330  to further encourage deflection of dirt particles from the perforations and thereby removing them from the airflow.  
     [0086] As the air flow passes through the perforations  356 , it begins traveling essentially along the outside of the central shaft  318 . It is been found that this air flow still maintains some rotational velocity. In the embodiment shown in FIG. 15, the airflow will strike vanes  358 . Vanes  358  will increase the rotational velocity component to the air flow. The air flow in the upper toroidal portion  364  will therefore have a tangential component to encourage additional cyclonic action in the toroidal section  364 .  
     [0087] As the air flow travels to the frusto-conical chamber  368 , the rotational velocity of the air flow will increase, driving dirt particles toward the frusto-conical wall  376  of the secondary cyclone chamber  370 . In addition, the axial velocity components will push the dirt particles to the top opening  390 . The tangential component will then direct the dirt particles to the outer secondary cyclonic chamber  370 , through the gap  388 . With very little airflow in the outer chamber of the secondary cyclonic chamber  370 , the velocity of the dirt particles drops dramatically and the dirt particles fall to the bottom  386  of the secondary cyclonic chamber  370 .  
     [0088] The remaining airflow, and those particles not having sufficient centripetal energy to be driven to the outside of the frusto-conical wall  376 , will be drawn through the top end  320  of the central shaft  316 , to be drawn to the vacuum source fluidly connected to the outlet opening  316 . A fine particulate filter (not shown) is inserted in the exhaust airstream to remove those fine particulates not extracted by the cyclonic separator.  
     [0089] An additional embodiment of a cyclonic separator  200  for a suction cleaner is shown in FIGS.  16 - 20 . Cyclonic separator  200  comprises a dirt bin  202 , a cyclonic housing  204 , first and second filter frames  208 ,  212 , first and second filter seals  206 ,  214 , filter medium  210 , and filter chamber lid  216 .  
     [0090] The dirt bin  202  is cylindrical in configuration, having an outer wall  220 , a bottom wall  222  having a central opening  224 , and a central cylindrical shaft  226  encompassing the aperture  224 , the cylindrical shaft  226  being concentric with the outer wall  220  of the dirt bin  202 . The central shaft  226  has an upper end  228  substantially even with an upper end  230  of the dirt bin outer wall  220 . The dirt bin thereby comprises a toroidal receptacle encompassed by the outer wall  220  and the central shaft  226 , and by the dirt bin lower surface  222  and the upper edges  228 ,  230  of the central shaft  226  and outer wall  220 .  
     [0091] The cyclone housing  204  is cylindrical, having an exterior diameter equal to the diameter of the dirt bin  202 . The cyclone housing  204  comprises a central cylindrical filter chamber  240  having an outer wall  242 , the diameter of the cylindrical filter chamber  240  being smaller than the exterior diameter of the cyclone housing  204 , but concentric therewith. The annular region defined between the outer wall  242  of the filter chamber  240  and the outer wall of the cyclone housing  204  comprises a spiral channel  250 . Channel  250  begins at an upper portion  252  of the cyclone housing  204  with an inlet opening  254 . The channel  250  then follows the perimeter of the cyclone housing in a downward spiral fashion to a channel outlet  256  on a lower portion of the cyclone housing  204 .  
     [0092] The upper portion of the filter chamber  240  comprises a filter chamber opening  258 . A lower portion of the filter chamber  240  comprises a central opening  260 , an annular filter seat  262  surrounding the central opening  260  on the lower portion of the filter chamber  240 , and an annular perforated inlet section  264 . The annular filter seat  262  is bounded on its interior and exterior edges by a raised rim  266 , each raised rim being annular and perpendicular to the base of the filter chamber  240 .  
     [0093] The filter chamber lid  216  is a flat disc having a diameter slightly greater than the diameter of the cylindrical filter chamber  240 , and having an annular depending rim  268  inset from the edge of lid  216  and adapted to be closely received within the opening  258  of filter chamber  240 . Filter chamber lid  216  further comprises two additional depending annular rims  270  each having a diameter corresponding to one of the rims  266  surrounding the annular filter seat  262  in the lower portion of the filter chamber  240 . The rims  270  bound an annular filter seat  272 , the annular filter seat  272  being centered on the underside of the circular filter chamber lid  216  for alignment with the filter seat  262 .  
     [0094] The first and second filter frames  208 ,  212  are identical in construction. The filter frames  208 ,  212  comprise a flat annular mating surface  280  including a pair of pin projections  282  and a pair of pin receiving openings  284  evenly spaced about the perimeter of the mating surface  280  so that the pins  282  of the first filter frame can be received in the openings  284  of the second filter frame, and vice versa, so that the mating surfaces  280  of the first and second filter frames  208 ,  212  can abut in a flush manner.  
     [0095] Referring to the first filter frame  208  for the purpose of describing the construction of the filter frames  208 ,  212 , the first filter frame  208  further comprises a number of ribs  286  depending from the mating surface  280  of the filter frame  208  in a slightly splayed manner, being substantially perpendicular to the plane of the mating surface  280  but canted slightly away from this center line of the filter frame  208 . The ribs  286  terminate in an annular base  290 . Based  290  comprises an inner annular rim  288  and an annular ring  292  with a raised outer rim  294 . The raised outer rim  294 , the ring  292  and the rim  288  form a shallow annular cavity  296  for receiving a lower portion of the filter medium  210 . Each of the filter frames  208 ,  212  further comprises an annular recess  298  on a face opposite the mating surface  280 , the recess  298  configured to receive annular filter seal  206 ,  214 .  
     [0096] The filter medium  210  is a hollow cylindrical arrangement of a pleated filter paper, the hollow cylinder having a diameter and wall thickness substantially corresponding to the width of the annular ring  292  of the filter frame  208 . The filter medium  210  has a height substantially equal to the distance between the annular rings  292  of the first and second filter frames  208 ,  212  when the frames  208 ,  212  are assembled with their respective mating surfaces  280  in abutment.  
     [0097] The cyclone separator  200  is assembled by placing the cyclone housing  204  in a sealing engagement with the upper end  230  of the dirt bin  202 . The outer wall of the cyclone housing  204  aligns with the outer wall  220  of the dirt bin  202 , and the upper end  228  of the central shaft  226  sealing engages the central opening  260  of the cyclone housing  204 .  
     [0098] The filter frame is assembled by placing a first filter seal  206  in the annular recess  298  of the first filter frame  208 , placing the hollow cylindrical filter medium  210  over the first filter frame  208  so that the lower portion of the filter medium  210  is received in the annular recess  296  of the first filter frame  208 , then inserting the second filter frame  212  into the filter medium  210  until the mating surface  280  of the second filter frame  212  abuts the mating surface  280  of the first filter frame  208  in a flush manner. The upper portion of the filter medium  210  is thus received in the annular recess  296  of the second filter frame  212 . The second filter seal is then placed in the annular recess  298  of the second filter frame  212 .  
     [0099] The filter assembly is then placed into the cyclone housing  204  so that the annular base of the first filter frame  208  is received in the annular filter seat  262  of the cyclone housing  204 . The filter chamber lid  216  can then be placed over the filter chamber opening  258  so that the depending rim  268  resides immediately inside the filter chamber wall  242 , and the annular base of the second filter frame  212  can be received in the annular filter seat  272  of the filter chamber lid  216  between the rims  270 .  
     [0100] The assembled cyclonic separator is now fluidly sealed from the atmosphere except for the inlet opening  254  of the spiral channel  250 , and the outlet opening  224  at the base of the dirt bin  202 . The inlet opening  254  and outlet opening  224  are fluidly connected through the spiral channel  250  into the interior of the dirt bin  202  and then through the annular inlet section  264  into the filter chamber  240 . Any fluid flow must then pass through the filter medium  210  to reach the central opening  260  at the base of the filter chamber  240 , from whence it travels through the central shaft  226  to the outlet opening  224 .  
     [0101] In a suction cleaner, the suction source is applied to the outlet opening  224 , thereby drawing a vacuum throughout the fluid path just described and the inlet opening  254  is then directed by known structures to a surface or object to be cleaned, thereby drawing dirt laden air into the cyclonic separator. The tangential flow through the spiral channel  250  will reduce the velocity in the particles in the air, causing them to fall under gravity into the toroidal dirt chamber of the dirt bin  202 . The air flow is further subjected to a severe change in direction as it must flow upwardly through the annular inlet section  264  of the filter chamber  240  before it can pass through the filter medium  210  to the exhaust outlet  224 .  
     [0102] While the invention has been specifically described in connection with certain specific embodiments thereof, it is to be understood that this is by way of illustration and not of limitation. Reasonable variation and modification are possible within the forgoing disclosure and drawings without departing from the spirit of the invention which is defined in the appended claims.