Abstract:
A surface cleaning apparatus comprises a cyclone bin assembly having a sidewall surrounding a contiguous interior volume and comprising multiple segments if different profile and width.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a continuation of U.S. patent application Ser. No. 14/512,245, filed on Oct. 10, 2014, now allowed, which itself is a continuation of U.S. patent application Ser. No. 13/508,970, filed on May 9, 2012, now issued U.S. Pat. No. 8,997,309, which is a national phase entry of application PCT/CA2012/000182 filed on Mar. 2, 2012, wherein application PCT/CA2012/000182 is a continuation-in-part of co-pending U.S. patent application Ser. No. 13/040,751, filed Mar. 4, 2011, now issued U.S. Pat. No. 9,204,772, and is a continuation-in-part of U.S. patent application Ser. No. 13/040,934, now abandoned, and is a continuation-in-part of U.S. patent application Ser. No. 13/040,955 filed Mar. 4, 2011, now issued U.S. Pat. No. 9,009,912, and is a continuation-in-part of U.S. patent application Ser. No. 13/040,731 filed Mar. 4, 2011, now issued U.S. Pat. No. 8,800,104, and is a Continuation-in-part of U.S. patent application Ser. No. 13/040,711, filed Mar. 4, 2011, now issued U.S. Pat. No. 8,863,352, and is a continuation-in-part of Ser. No. 13/040,768 filed Mar. 4, 2011, now issued U.S. Pat. No. 8,528,164 U.S. patent application Ser. No. 13/040,731 filed Mar. 4, 2011, and is a continuation-in-part of U.S. patent application Ser. No. 13/040,934 filed Mar. 4, 2011, now issued U.S. Pat. No. 8,528,164, each of those applications being incorporated herein in their entirety by reference. 
     
    
     FIELD 
       [0002]    The disclosure relates to surface cleaning apparatuses, such as vacuum cleaners. 
       INTRODUCTION 
       [0003]    Various constructions for surface cleaning apparatuses, such as vacuum cleaners, are known. Currently, many surface cleaning apparatuses are constructed using at least one cyclonic cleaning stage. Air is drawn into the vacuum cleaners through a dirty air inlet and conveyed to a cyclone inlet. The rotation of the air in the cyclone results in some of the particulate matter in the airflow stream being disentrained from the airflow stream. This material is then collected in a dirt bin collection chamber, which may be at the bottom of the cyclone or in a direct collection chamber exterior to the cyclone chamber (see for example WO2009/026709 and U.S. Pat. No. 5,078,761). One or more additional cyclonic cleaning stages and/or filters may be positioned downstream from the cyclone. 
       SUMMARY 
       [0004]    The following summary is provided to introduce the reader to the more detailed discussion to follow. The summary is not intended to limit or define the claims. 
         [0005]    According to one broad aspect of the teachings described herein, a dirt collection chamber for one or more cyclone chambers extends from a dirt inlet towards a dirt collection area. For example, the dirt inlet may be in an upper portion of the dirt collection chamber and the dirt collection area may be the floor of the dirt collection chamber. The dirt collection chamber comprises a sidewall (preferably an outer sidewall) that extends longitudinally between opposing first and second ends of the dirt collection chamber. Air circulating within the dirt collection chamber may flow along the sidewall. For example, air may exit the dirt outlet of the cyclone chamber and rotate around the dirt collection chamber and travel towards the dirt collection area. The air will at some point travel in the reverse direction towards the dirt inlet and re-enter the cyclone chamber. The dirt collection chamber may be configured such that the cross sectional area of the dirt collection chamber in a plane transverse to its length changes at least once along the length of the dirt collection chamber. In some embodiments, the cross-sectional area at the first end of the dirt collection chamber is different than the cross-sectional area at the second end of the dirt collection chamber. 
         [0006]    An advantage of this configuration may be that changes in the cross-sectional area may be used to enhance the separation efficiency of the cyclone chamber and associated dirt collection chamber. By varying the transverse cross sectional area of the dirt collection chamber, the flow dynamics of the air in the dirt collection chamber may be varied and the amount of dirt that is disentrained from the air may be decreased, or the amount of dirt that is re-entrained may be reduced. For example, if the cross sectional area of the portion of the dirt collection chamber distal to the dirt inlet (e.g., the lower portion) is less than the opposed portion (e.g. upper portion) adjacent the dirt inlet, then the air will slow down as it enters the upper portion. As the velocity decreases, the amount of dirt that may be re-entrained in the return airflow may decrease. If the cross sectional area of the portion of the dirt collection chamber distal to the dirt inlet (e.g., the lower portion) is greater than the opposed portion (e.g. upper portion) adjacent the dirt inlet, then the air will slow down as it enters the lower portion allowing more dirt to be disentrained. 
         [0007]    The cyclone chamber and dirt collection chamber assembly may be used in any surface cleaning apparatus. The surface cleaning apparatus comprises an air flow passage extending from a dirty air inlet to a clean air outlet. A suction motor is provided in the air flow passage, and a cyclone bin assembly is provided in the air flow passage, preferably upstream from the suction motor. The cyclone bin assembly may comprise the cyclone chamber and a dirt collection chamber. Dirty air from the dirty air inlet may circulate within the cyclone chamber and may exit the cyclone chamber to circulate within the dirt collection chamber. 
         [0008]    The cyclone bin assembly may also comprise a fine particle separator, to help separate relatively fine dirt particles from the dirty air. The fine particle separator comprises a flow chamber through which the dirty air may circulate. Dirty air, carrying entrained fine dirt particles may flow from the cyclone chamber into the fine particle separator. Air exiting the fine particle separator may re-enter the cyclone chamber, and travel to the suction motor via a cyclone air outlet. 
         [0009]    The fine particle separator is configured so that air circulating in the flow chamber may travel at a relatively high velocity, and may travel faster than the air circulating within the cyclone chamber. To help increase the air flow velocity the cross-sectional area of the flow chamber, in the flow direction, may be varied, and preferably is reduced. Accelerating the dirty air to a relatively higher velocity may help disentrain fine dirt particles. 
         [0010]    The air outlet of the fine particle separator flow chamber may be configured to disrupt the flow of air exiting the flow chamber. Disrupting the flow of air, for example by introducing eddy currents and/or turbulence and/or directing the air away from the cyclone dirt outlet, may help separate fine dirt particles from the air stream. Separated dirt particles may fall into the dirt collection chamber. 
         [0011]    An advantage of this configuration may be a more efficient separation of fine dirt particles from the dirty air stream. Separating fine dirt particles from the dirty air stream in the fine particle separator may help prevent the fine dirt particles from continuing downstream from the cyclone bin assembly, and, for example, fouling the suction motor and/or a pre-motor filter. 
         [0012]    In accordance with this aspect a surface cleaning apparatus comprises an air flow passage extending from a dirty air inlet to a clean air outlet. The air flow passage includes a suction motor. The surface cleaning apparatus may also comprise a cyclone chamber provided in the air flow passage. The cyclone chamber may comprise a cyclone air inlet, a cyclone air outlet and a dirt outlet. The surface cleaning apparatus may comprise a dirt collection chamber having a dirt inlet, a dirt collection chamber first end, an opposed dirt collection chamber second end and a longitudinally extending sidewall. The sidewall may comprise a portion that has a longitudinal length and extends away from the dirt inlet towards the opposed dirt collection chamber second end. A transverse cross sectional area of the dirt collection chamber may vary at least once along the length of the portion of the sidewall. 
         [0013]    The dirt inlet may be positioned adjacent the dirt collection chamber first end. 
         [0014]    A dirt collection area may be provided at the opposed dirt collection chamber second end. 
         [0015]    The dirt collection chamber first end may be an upper end. The dirt inlet may be provided at the upper end, and a dirt collection area may be provided in a lower portion of the dirt collection chamber. 
         [0016]    The dirt collection chamber may be exterior to the cyclone chamber. 
         [0017]    The dirt collection chamber may surround at least a portion of the cyclone chamber. 
         [0018]    The dirt collection chamber may surround the cyclone chamber. 
         [0019]    The cyclone chamber and the dirt collection chamber may be provided in a cyclone bin assembly. The cyclone bin assembly may be removably mounted to the surface cleaning apparatus. 
         [0020]    The portion of the sidewall may include at least one discontinuity. 
         [0021]    The portion of the sidewall may extend inwardly at a position along its length whereby the transverse cross sectional area may be reduced. 
         [0022]    The portion of the sidewall may extend inwardly at a position along its length whereby the transverse cross sectional area may be increased. 
         [0023]    The dirt collection chamber may surround at least a portion of the cyclone chamber. The dirt collection chamber may have an inner side adjacent the cyclone chamber and an outer side spaced from the cyclone chamber. The portion of the sidewall may be provided at the outer side. 
         [0024]    The portion of the sidewall may include at least one discontinuity. 
         [0025]    The portion of the sidewall may extend inwardly at a position along its length whereby the transverse cross sectional area may be reduced. 
         [0026]    The portion of the sidewall may extend inwardly at a position along its length whereby the transverse cross sectional area may be increased. 
         [0027]    The cyclone air inlet may be at a first end of the cyclone chamber. The dirt outlet may be provided at a second opposed end of the cyclone chamber. 
         [0028]    The dirt inlet may be at an upper end of the cyclone chamber. 
         [0029]    The surface cleaning apparatus may comprise a rib extending between the inner side and the outer side. The rib may be provided along the portion of the sidewall. 
         [0030]    The rib may extend only part way along the portion of the sidewall. 
         [0031]    According to another broad aspect of the teachings described herein, a surface cleaning apparatus comprises a cyclone chamber and a fine particle separator in flow communication with the cyclone chamber via the cyclone chamber dirt outlet. The fine particle separator helps to separate relatively fine dirt particles from the dirty air. The fine particle separator comprises a flow chamber through which the dirty air may circulate. Dirty air, carrying entrained fine dirt particles may flow from the cyclone chamber into the fine particle separator. Air exiting the fine particle separator may re-enter the cyclone chamber, and travel to the suction motor via a cyclone air outlet. 
         [0032]    The fine particle separator is configured so that air circulating in the flow chamber may travel at a relatively high velocity, and may travel faster than the air circulating within the cyclone chamber to thereby separate finer dirt particles than those separated in the cyclone chamber. To help increase the air flow velocity, the cross-sectional area of the flow chamber, in the flow direction, may be varied, and preferably is reduced. Accelerating the dirty air to a relatively higher velocity may help disentrain fine dirt particles. 
         [0033]    The air outlet of the fine particle separator flow chamber may be configured to disrupt the flow of air exiting the flow chamber. Disrupting the flow of air, for example by introducing eddy currents and/or turbulence and/or directing the air away from the cyclone dirt outlet, may help separate fine dirt particles from the air stream. Separated dirt particles may fall into the dirt collection chamber. 
         [0034]    An advantage of this configuration may be a more efficient separation of fine dirt particles from the dirty air stream. Separating fine dirt particles from the dirty air stream in the fine particle separator may help prevent the fine dirt particles from continuing downstream from the cyclone bin assembly, and, for example, fouling the suction motor and/or a pre-motor filter. 
         [0035]    The cyclone air outlet may be in communication with an exit duct conduit (which may be a down duct depending upon the orientation of the duct conduit) extending away from the cyclone air outlet and preferably through (e.g., linearly through) a dirt collection chamber having a wall (e.g., a floor) facing the end of the cyclone chamber with the air outlet. For example, the down duct may extend from the floor of the cyclone chamber to the floor of the dirt collection chamber. Reinforcing ribs may extend between the down duct and the floor of the cyclone chamber. The ribs may help reduce vibrations in the down duct and/or the floor of the dirt collection chamber, including, for example, vibrations induced by air flowing through the down duct. Optionally, the down duct and/or the support ribs may be removable. 
         [0036]    An advantage of this configuration may be that vibration of the down duct and/or the floor of the dirt collection chamber may be reduced. Reducing the vibration of the down duct and/or the floor of the dirt collection chamber may help reduce the overall amount of noise generated by the surface cleaning apparatus and/or improve the separation efficiency of the cyclone chamber and the dirt collection chamber. 
         [0037]    The dirt collection chamber may extend from a dirt inlet towards a dirt collection area. For example, the dirt inlet may be in an upper portion of the dirt collection chamber and the dirt collection area may be the floor of the dirt collection chamber. The dirt collection chamber comprises a sidewall (preferably an outer sidewall) that extends longitudinally between opposing first and second ends of the dirt collection chamber. Air circulating within the dirt collection chamber may flow along the sidewall. For example, air may exit the dirt outlet of the cyclone chamber and rotate around the dirt collection chamber and travel towards the dirt collection area. The air will at some point travel in the reverse direction towards the dirt inlet and re-enter the cyclone chamber. The dirt collection chamber may be configured such that the cross sectional area of the dirt collection chamber in a plane transverse to its length changes at least once along the length of the dirt collection chamber. In some embodiments, the cross-sectional area at the first end of the dirt collection chamber is different than the cross-sectional area at the second end of the dirt collection chamber. 
         [0038]    An advantage of this configuration may be that changes in the cross-sectional area may be used to enhance the separation efficiency of the cyclone chamber and associated dirt collection chamber. By varying the transverse cross sectional area of the dirt collection chamber, the flow dynamics of the air in the dirt collection chamber may be varied and the amount of dirt that is disentrained from the air may be decreased, or the amount of dirt that is re-entrained may be reduced. For example, if the cross sectional area of the portion of the dirt collection chamber distal to the dirt inlet (e.g., the lower portion) is less than the opposed portion (e.g. upper portion) adjacent the dirt inlet, then the air will slow down as it enters the upper portion. As the velocity decreases, the amount of dirt that may be re-entrained in the return airflow may decrease. If the cross sectional area of the portion of the dirt collection chamber distal to the dirt inlet (e.g., the lower portion) is greater than the opposed portion (e.g. upper portion) adjacent the dirt inlet, then the air will slow down as it enters the lower portion allowing more dirt to be disentrained. 
         [0039]    The cyclone chamber and dirt collection chamber assembly may be used in any surface cleaning apparatus. The surface cleaning apparatus comprises an air flow passage extending from a dirty air inlet to a clean air outlet. A suction motor is provided in the air flow passage, and a cyclone bin assembly is provided in the air flow passage, preferably upstream from the suction motor. The cyclone bin assembly may comprise a cyclone chamber and a dirt collection chamber. Dirty air from the dirty air inlet may circulate within the cyclone chamber and may exit the cyclone chamber to circulate within the dirt collection chamber. 
         [0040]    In accordance with this aspect, a surface cleaning apparatus comprises an air flow passage extending from a dirty air inlet to a clean air outlet. The air flow passage includes a suction motor. The surface cleaning apparatus may also comprise a cyclone chamber provided in the air flow passage. The cyclone chamber may comprise a cyclone air inlet, a cyclone air outlet, a dirt outlet and a cyclone chamber wall. The surface cleaning apparatus may also comprise a fine particle separator. The fine particle separator may comprise an annular flow channel, a fine particle separator inlet in communication with the cyclone chamber via the cyclone dirt outlet, a fine particle separator dirt outlet and a fine particle separator sidewall. The surface cleaning apparatus may also comprise a dirt collection chamber in communication with the fine particle separator dirt outlet. The dirt collection chamber may comprise a dirt collection chamber sidewall. 
         [0041]    The fine particle separator may surround at least a portion of the cyclone chamber. 
         [0042]    The fine particle separator inlet may comprise an inlet for air and fine particles to enter the fine particle separator and an outlet for air to re-enter the cyclone chamber. 
         [0043]    The fine particle separator inlet may be the sole communication between the cyclone chamber and the fine particle separator. 
         [0044]    The cyclone dirt outlet may comprise a slot that extends part way around the cyclone chamber wall. 
         [0045]    The slot may be provided adjacent a first end of the cyclone chamber. The cyclone air inlet may be provided at a second opposed end of the cyclone chamber. 
         [0046]    The cyclone chamber air outlet may be provided at the second opposed end of the cyclone chamber. 
         [0047]    The first end of the cyclone chamber may be an upper end of the cyclone chamber. 
         [0048]    The fine particle separator may be positioned above the dirt collection chamber. 
         [0049]    The annular flow channel may have an axis of rotation and a cross sectional area in a plane parallel to the axis of rotation. 
         [0050]    The cross sectional area may vary at at least one location in the annular flow channel. 
         [0051]    The cross sectional area may decrease in a downstream direction. 
         [0052]    The cross sectional area may decrease in a downstream portion of the annular flow channel towards the fine particle separator inlet. 
         [0053]    A width and/or a height of the annular flow channel may be varied to vary the cross sectional area. 
         [0054]    A downstream portion of the annular flow channel adjacent the fine particle separator inlet may be configured to be spaced further radially outwardly from the fine particle separator inlet than a portion of the annular flow channel upstream thereof. 
         [0055]    The fine particle separator may have an inner wall. The inner wall may comprise a ramp section adjacent the fine particle separator inlet which extends radially outwardly and in a direction of rotation. 
         [0056]    The fine particle separator may extend between the fine particle separator sidewall and the cyclone chamber wall. 
         [0057]    The fine particle separator may comprise an annular flow channel having a closed end and an opposed open end that may comprise the fine particle separator dirt outlet. The dirt collection chamber may extend away from the fine particle separator dirt outlet. 
         [0058]    The fine particle separator may comprise an annular flow channel having an upper end and an open lower end that may comprise the fine particle separator dirt outlet and the dirt collection chamber extends away from the fine particle separator dirt outlet and surrounds at least a portion of the cyclone chamber. 
         [0059]    The dirt collection chamber may comprise an annular region extending around the cyclone chamber. 
         [0060]    The surface cleaning apparatus may comprise a rib provided in the dirt collection chamber. The rib may extend between the dirt collection chamber sidewall and a radially inner wall of the dirt collection chamber. 
         [0061]    The rib may extend only part way along the radially inner wall. 
         [0062]    The dirt collection chamber sidewall may comprise an extension of the fine particle separator sidewall and the radially inner wall may comprise a portion of the cyclone chamber wall. 
         [0063]    The dirt collection chamber sidewall may comprise an extension of the fine particle separator sidewall. 
         [0064]    The dirt collection chamber sidewall may comprise a discontinuity along its length. 
         [0065]    According to another broad aspect of the teachings described herein, a dirt collection chamber for one or more cyclone chambers extends from a dirt inlet towards a dirt collection area. For example, the dirt inlet may be in an upper portion of the dirt collection chamber and the dirt collection area may be the floor of the dirt collection chamber. The dirt collection chamber comprises an annular flow region with a transverse rib or baffle extending part way and, preferably, the entire width of the dirt collection chamber between the inner and outer sidewalls of the annular flow region (e.g., the rib may extend between an outer surface of the cyclone chamber and an opposing inner surface of the surrounding dirt collection chamber). A portion of the dirty air circulating within the cyclone chamber may exit the cyclone chamber via the dirt outlet and circulate within the surrounding dirt collection chamber. Preferably, the rib is adjacent the dirt outlet of the cyclone chamber. More preferably, the rib is positioned between the dirt outlet and a discontinuity in the dirt collection chamber sidewall. The rib may extend part way along the length of the annular dirt collection region. 
         [0066]    An advantage of this configuration may be that dirty air circulating within the dirt collection chamber may be disrupted by the rib, which may help disentrain dirt particles from the dirty air stream. Another advantage of this design is that rotational flow of air in the dirt collection chamber may be reduced or stopped thereby reducing the re-entrainment of separated particulate material. 
         [0067]    The dirt collection chamber may comprise a sidewall (preferably an outer sidewall) that extends longitudinally between opposing first and second ends of the dirt collection chamber. Air that may be circulating within the dirt collection chamber may flow along the sidewall. For example, air may exit the dirt outlet of the cyclone chamber and rotate around the dirt collection chamber and travel towards the dirt collection area. The air will at some point travel in the reverse direction towards the dirt inlet and re-enter the cyclone chamber. The dirt collection chamber may be configured such that the cross sectional area of the dirt collection chamber in a plane transverse to its length changes at least once along the length of the dirt collection chamber. In some embodiments, the cross-sectional area at the first end of the dirt collection chamber is different than the cross-sectional area at the second end of the dirt collection chamber. 
         [0068]    An advantage of this configuration may be that changes in the cross-sectional area may be used to enhance the separation efficiency of the cyclone chamber and associated dirt collection chamber. By varying the transverse cross sectional area of the dirt collection chamber, the flow dynamics of the air in the dirt collection chamber may be varied and the amount of dirt that is disentrained from the air may be decreased, or the amount of dirt that is re-entrained may be reduced. For example, if the cross sectional area of the portion of the dirt collection chamber distal to the dirt inlet (e.g., the lower portion) is less than the opposed portion (e.g. upper portion) adjacent the dirt inlet, then the air will slow down as it enters the upper portion. As the velocity decreases, the amount of dirt that may be re-entrained in the return airflow may decrease. If the cross sectional area of the portion of the dirt collection chamber distal to the dirt inlet (e.g., the lower portion) is greater than the opposed portion (e.g. upper portion) adjacent the dirt inlet, then the air will slow down as it enters the lower portion allowing more dirt to be disentrained. 
         [0069]    The cyclone chamber and dirt collection chamber assembly may be used in any surface cleaning apparatus. The surface cleaning apparatus comprises an air flow passage extending from a dirty air inlet to a clean air outlet. A suction motor is provided in the air flow passage, and a cyclone bin assembly is provided in the air flow passage, preferably upstream from the suction motor. The cyclone bin assembly may comprise the cyclone chamber and a dirt collection chamber. Dirty air from the dirty air inlet may circulate within the cyclone chamber and may exit the cyclone chamber to circulate within the dirt collection chamber. 
         [0070]    The cyclone bin assembly may also comprise a fine particle separator, to help separate relatively fine dirt particles from the dirty air. The fine particle separator may comprise a flow chamber through which the dirty air may circulate. Dirty air, carrying entrained fine dirt particles may flow from the cyclone chamber into the fine particle separator. Air exiting the fine particle separator may re-enter the cyclone chamber, and travel to the suction motor via a cyclone air outlet. 
         [0071]    The fine particle separator may be configured so that air circulating in the flow chamber may travel at a relatively high velocity, and may travel faster than the air circulating within the cyclone chamber. To help increase the air flow velocity, the cross-sectional area of the flow chamber, in the flow direction, may be varied, and preferably is reduced. Accelerating the dirty air to a relatively higher velocity may help disentrain fine dirt particles. 
         [0072]    The air outlet of the fine particle separator flow chamber may be configured to disrupt the flow of air exiting the flow chamber. Disrupting the flow of air, for example by introducing eddy currents and/or turbulence and/or directing the air away from the cyclone dirt outlet, may help separate fine dirt particles from the air stream. Separated dirt particles may fall into the dirt collection chamber. 
         [0073]    An advantage of this configuration may be a more efficient separation of fine dirt particles from the dirty air stream. Separating fine dirt particles from the dirty air stream in the fine particle separator may help prevent the fine dirt particles from continuing downstream from the cyclone bin assembly, and, for example, fouling the suction motor and/or a pre-motor filter. 
         [0074]    In accordance with this aspect, a surface cleaning apparatus may comprise an air flow passage extending from a dirty air inlet to a clean air outlet. The air flow passage includes a suction motor. The surface cleaning apparatus may also comprise a cyclone chamber in the air flow passage. The cyclone chamber may comprise a cyclone air inlet, a cyclone air outlet, a cyclone dirt outlet and a cyclone chamber wall. The surface cleaning apparatus may also comprise a dirt collection chamber having a dirt inlet in communication with the cyclone dirt outlet. At least a portion of the cyclone chamber may be in the dirt collection chamber. The dirt collection chamber may comprise an inner side adjacent the cyclone chamber and an outer side spaced from the cyclone chamber and defined by a dirt collection chamber sidewall. A rib may extend between the inner side and the outer side. 
         [0075]    The rib extends only part way along the inner side. 
         [0076]    The dirt collection chamber may have a first end and a second opposed end. The dirt inlet may be provided at the first end and the rib may be spaced from the dirt inlet towards the second opposed end. 
         [0077]    The dirt inlet may be positioned adjacent a first end of the dirt collection chamber. 
         [0078]    The dirt collection chamber may comprise a dirt collection area that is provided at a second end opposed to the first end. 
         [0079]    The dirt inlet may be at an upper end of the dirt collection chamber and the dirt collection area may be in a lower portion of the dirt collection chamber. 
         [0080]    The dirt collection chamber may surround the cyclone chamber. 
         [0081]    The dirt collection chamber may extend part way around the cyclone chamber to define a sector. The rib may be provided at a location spaced from each end of the sector. 
         [0082]    The cyclone chamber and the dirt collection chamber may be provided in a cyclone bin assembly. The cyclone bin assembly may be removably mounted to the surface cleaning apparatus. 
         [0083]    The dirt collection chamber sidewall may include at least one discontinuity. 
         [0084]    The dirt collection chamber may have a first end and a second opposed end. The dirt inlet may be provided at the first end and the rib may be spaced from the dirt inlet towards the second opposed end. 
         [0085]    The rib may be provided between the cyclone dirt outlet and the discontinuity. 
         [0086]    A portion of the dirt collection chamber sidewall may extend inwardly at a position along its length. 
         [0087]    A portion of the dirt collection chamber sidewall may extend outwardly at a position along its length 
         [0088]    The cyclone dirt outlet may comprise a slot that extends part way around the cyclone chamber wall. 
         [0089]    The slot may be provided adjacent a first end of the cyclone chamber and the cyclone air inlet may be provided at a second opposed end of the cyclone chamber. 
         [0090]    The cyclone chamber air outlet may be provided at the second opposed end of the cyclone chamber. 
         [0091]    The first end of the cyclone chamber may be an upper end of the cyclone chamber. 
         [0092]    The surface cleaning apparatus may comprise an annular flow chamber exterior to the cyclone chamber. The annular flow chamber may have a first end and a second end spaced from the first end and in communication with the dirt collection chamber. 
         [0093]    The annular flow chamber may comprise a volume contiguous with the dirt collection chamber and located between the first end of the annular flow chamber and the rib. 
         [0094]    The rib may have an end facing the first end. The end may be spaced from the first end of the annular flow chamber. 
         [0095]    The cyclone dirt outlet may be the dirt collection chamber dirt inlet. 
         [0096]    According to yet another broad aspect of the teachings described herein, a cyclone bin assembly comprises a cyclone chamber and a dirt collection chamber. The cyclone air outlet is in communication with an exit duct conduit (which may be a down duct depending upon the orientation of the duct conduit) extending away from the cyclone air outlet and preferably through (e.g., linearly through) a dirt collection chamber having a wall (e.g., a floor) facing the end of the cyclone chamber with the air outlet. The down duct may extend from the floor of the cyclone chamber to the floor of the dirt collection chamber. Reinforcing ribs may be provided and may extend between the down duct and the floor of the cyclone chamber. The ribs may help reduce vibrations in the down duct and/or the floor of the dirt collection chamber, including, for example, vibrations induced by air flowing through the down duct. Optionally, the down duct and/or the support ribs may be removable. 
         [0097]    An advantage of this configuration may be that vibration of the down duct and/or the floor of the dirt collection chamber may be reduced. Reducing the vibration of the down duct and/or the floor of the dirt collection chamber may help reduce the overall amount of noise generated by the surface cleaning apparatus and/or improve the separation efficiency of the cyclone chamber and the dirt collection chamber. 
         [0098]    The dirt collection chamber may extend from a dirt inlet towards a dirt collection area. For example, the dirt inlet may be in an upper portion of the dirt collection chamber and the dirt collection area may be the floor of the dirt collection chamber. The dirt collection chamber comprises a sidewall (preferably an outer sidewall) that extends longitudinally between opposing first and second ends of the dirt collection chamber. Air circulating within the dirt collection chamber may flow along the sidewall. For example, air may exit the dirt outlet of the cyclone chamber and rotate around the dirt collection chamber and travel towards the dirt collection area. The air will at some point travel in the reverse direction towards the dirt inlet and re-enter the cyclone chamber. The dirt collection chamber may be configured such that the cross sectional area of the dirt collection chamber in a plane transverse to its length changes at least once along the length of the dirt collection chamber. In some embodiments, the cross-sectional area at the first end of the dirt collection chamber is different than the cross-sectional area at the second end of the dirt collection chamber. 
         [0099]    An advantage of this configuration may be that changes in the cross-sectional area may be used to enhance the separation efficiency of the cyclone chamber and associated dirt collection chamber. By varying the transverse cross sectional area of the dirt collection chamber, the flow dynamics of the air in the dirt collection chamber may be varied and the amount of dirt that is disentrained from the air may be decreased, or the amount of dirt that is re-entrained may be reduced. For example, if the cross sectional area of the portion of the dirt collection chamber distal to the dirt inlet (e.g., the lower portion) is less than the opposed portion (e.g. upper portion) adjacent the dirt inlet, then the air will slow down as it enters the upper portion. As the velocity decreases, the amount of dirt that may be re-entrained in the return airflow may decrease. If the cross sectional area of the portion of the dirt collection chamber distal to the dirt inlet (e.g., the lower portion) is greater than the opposed portion (e.g. upper portion) adjacent the dirt inlet, then the air will slow down as it enters the lower portion allowing more dirt to be disentrained. 
         [0100]    The cyclone chamber and dirt collection chamber assembly may be used in any surface cleaning apparatus. The surface cleaning apparatus comprises an air flow passage extending from a dirty air inlet to a clean air outlet. A suction motor is provided in the air flow passage, and a cyclone bin assembly is provided in the air flow passage, preferably upstream from the suction motor. The cyclone bin assembly may comprise the cyclone chamber and a dirt collection chamber. Dirty air from the dirty air inlet may circulate within the cyclone chamber and may exit the cyclone chamber to circulate within the dirt collection chamber. 
         [0101]    The cyclone bin assembly may also comprise a fine particle separator, to help separate relatively fine dirt particles from the dirty air. The fine particle separator may comprise a flow chamber through which the dirty air may circulate. Dirty air, carrying entrained fine dirt particles may flow from the cyclone chamber into the fine particle separator. Air exiting the fine particle separator may re-enter the cyclone chamber, and travel to the suction motor via a cyclone air outlet. 
         [0102]    The fine particle separator is configured so that air circulating in the flow chamber may travel at a relatively high velocity, and may travel faster than the air circulating within the cyclone chamber. To help increase the air flow velocity the cross-sectional area of the flow chamber, in the flow direction, may be varied, and preferably is reduced. Accelerating the dirty air to a relatively higher velocity may help disentrain fine dirt particles. 
         [0103]    The air outlet of the fine particle separator flow chamber may be configured to disrupt the flow of air exiting the flow chamber. Disrupting the flow of air, for example by introducing eddy currents and/or turbulence and/or directing the air away from the cyclone dirt outlet, may help separate fine dirt particles from the air stream. Separated dirt particles may fall into the dirt collection chamber. 
         [0104]    An advantage of this configuration may be a more efficient separation of fine dirt particles from the dirty air stream. Separating fine dirt particles from the dirty air stream in the fine particle separator may help prevent the fine dirt particles from continuing downstream from the cyclone bin assembly, and, for example, fouling the suction motor and/or a pre-motor filter. 
         [0105]    In accordance with this aspect, a surface cleaning apparatus may comprise an air flow passage extending from a dirty air inlet to a clean air outlet and a suction motor. The surface cleaning apparatus may comprise a cyclone chamber provided in the air flow passage. The cyclone chamber may comprise a cyclone chamber first end and a cyclone chamber second opposed end, a cyclone air inlet, a cyclone air outlet provided at the cyclone chamber second opposed end and a cyclone chamber wall. An air exit conduit may be exterior to the cyclone chamber and may extend from the cyclone air outlet. At least one reinforcing rib may be positioned in abutting relationship with the air exit conduit and the cyclone chamber second opposed end. 
         [0106]    The reinforcing rib may be connected to the air exit conduit. 
         [0107]    The reinforcing rib may be connected to the cyclone chamber second opposed end. 
         [0108]    The air exit conduit may extend through a dirt collection chamber that may be positioned exterior to the cyclone chamber. 
         [0109]    The air exit conduit may be removably mounted to the cyclone chamber. 
         [0110]    The cyclone chamber may comprise a vortex finder and the vortex finder remains in position when the air exit conduit is removed. 
         [0111]    The cyclone air inlet may be located adjacent the cyclone chamber second opposed end. 
         [0112]    The cyclone chamber may comprise a cyclone dirt outlet located adjacent the cyclone chamber first end. The surface cleaning apparatus may comprise a dirt collection chamber in communication with the cyclone dirt outlet. 
         [0113]    The dirt collection chamber may extend at least part way around the cyclone chamber. The dirt collection chamber may have a dirt collection chamber first end and a dirt collection chamber second opposed end that may be spaced from and may face the cyclone chamber second opposed end. The air exit conduit may extend between the cyclone chamber second opposed end and the dirt collection chamber second opposed end. 
         [0114]    The surface cleaning apparatus may comprise a cyclone bin assembly that is removably mounted to the surface cleaning apparatus, the cyclone bin assembly comprising the cyclone chamber and a dirt collection chamber. 
         [0115]    The air exit conduit may extend through the dirt collection chamber. 
         [0116]    The cyclone air outlet may be provided in the cyclone chamber second opposed end. The dirt collection chamber may have a dirt collection chamber end that is spaced from and faces the cyclone chamber second opposed end. The air exit conduit may extend between the cyclone chamber second opposed end and the dirt collection chamber end. 
         [0117]    The dirt collection chamber end may be openable. 
         [0118]    The dirt collection chamber end may have an air exit port in communication with the air exit conduit and the air exit conduit remains in position when the dirt collection chamber end is opened. 
         [0119]    The air exit conduit may be removably mounted to the cyclone chamber. 
         [0120]    The cyclone chamber may comprise a vortex finder and the vortex finder may remain in position when the air exit conduit is removed. 
         [0121]    The cyclone air inlet may be located adjacent the cyclone chamber second opposed end. 
         [0122]    The cyclone chamber may comprise a cyclone dirt outlet located adjacent the cyclone chamber first end. The surface cleaning apparatus may comprise a dirt collection chamber in communication with the cyclone dirt outlet. 
         [0123]    According to yet another broad aspect of the teachings described herein, a dirt collection chamber is provided with one or more recessed areas on the outer sidewall of the dirt collection chamber. The dirt collection chamber is separate from (e.g., exterior to) the cyclone chamber. Preferably, the recess is a longitudinally extending recess. The recess may extend from the floor of the dirt collection chamber to the floor of the cyclone chamber, and may extend past the floor of the cyclone chamber. The recess provides a discontinuity on the inner surface of the dirt collection chamber sidewall. The discontinuity may disrupt the flow of the dirty air flowing along the inner surface of the sidewall, which may help disentrain dirt particles from the dirty airflow. The ejected dirt particles may collect within the recess, and may fall to the floor of the dirt collection chamber if the recess extends to the floor. The recess may also help inhibit re-entrainment of the ejected dirt particles. 
         [0124]    The leading or upstream side of the recess preferably forms a relatively sharp corner with the inner surface of the sidewall. The relatively sharp corner may increase the disruptions in the air flow. 
         [0125]    An advantage of this configuration may be a more efficient separation of dirt particles from the dirty air stream. Separating dirt particles from the dirty air stream in the dirt collection chamber may help prevent the fine dirt particles from continuing downstream from the cyclone bin assembly, and, for example, fouling the suction motor and/or a pre-motor filter. 
         [0126]    A cyclone bin assembly may comprise a cyclone chamber and the dirt collection chamber. The cyclone air outlet may be in communication with an exit duct conduit (which may be a down duct depending upon the orientation of the duct conduit) extending away from the cyclone air outlet and preferably through (e.g., linearly through) a dirt collection chamber facing the end of the cyclone chamber with the air outlet. The down duct may extend from the floor of the cyclone chamber to the floor of the dirt collection chamber. Reinforcing ribs may extend between the down duct and the floor of the cyclone chamber. The ribs may help reduce vibrations in the down duct and/or the floor of the dirt collection chamber, including, for example, vibrations induced by air flowing through the down duct. Optionally, the down duct and/or the support ribs may be removable. 
         [0127]    An advantage of this configuration may be that vibration of the down duct and/or the floor of the dirt collection chamber may be reduced. Reducing the vibration of the down duct and/or the floor of the dirt collection chamber may help reduce the overall amount of noise generated by the surface cleaning apparatus and/or improve the separation efficiency of the cyclone chamber and the dirt collection chamber. 
         [0128]    The dirt collection chamber may extend from a dirt inlet towards a dirt collection area. For example, the dirt inlet may be in an upper portion of the dirt collection chamber and the dirt collection area may be the floor of the dirt collection chamber. The dirt collection chamber comprises a sidewall (preferably an outer sidewall) that extends longitudinally between opposing first and second ends of the dirt collection chamber. Air circulating within the dirt collection chamber may flow along the sidewall. For example, air may exit the dirt outlet of the cyclone chamber and rotate around the dirt collection chamber and travel towards the dirt collection area. The air will at some point travel in the reverse direction towards the dirt inlet and re-enter the cyclone chamber. The dirt collection chamber may be configured such that the cross sectional area of the dirt collection chamber in a plane transverse to its length changes at least once along the length of the dirt collection chamber. In some embodiments, the cross-sectional area at the first end of the dirt collection chamber is different than the cross-sectional area at the second end of the dirt collection chamber. 
         [0129]    An advantage of this configuration may be that changes in the cross-sectional area may be used to enhance the separation efficiency of the cyclone chamber and associated dirt collection chamber. By varying the transverse cross sectional area of the dirt collection chamber, the flow dynamics of the air in the dirt collection chamber may be varied and the amount of dirt that is disentrained from the air may be decreased, or the amount of dirt that is re-entrained may be reduced. For example, if the cross sectional area of the portion of the dirt collection chamber distal to the dirt inlet (e.g., the lower portion) is less than the opposed portion (e.g. upper portion) adjacent the dirt inlet, then the air will slow down as it enters the upper portion. As the velocity decreases, the amount of dirt that may be re-entrained in the return airflow may decrease. If the cross sectional area of the portion of the dirt collection chamber distal to the dirt inlet (e.g., the lower portion) is greater than the opposed portion (e.g. upper portion) adjacent the dirt inlet, then the air will slow down as it enters the lower portion allowing more dirt to be disentrained. 
         [0130]    The cyclone chamber and dirt collection chamber assembly may be used in any surface cleaning apparatus. The surface cleaning apparatus comprises an air flow passage extending from a dirty air inlet to a clean air outlet. A suction motor is provided in the air flow passage, and a cyclone bin assembly is provided in the air flow passage, preferably upstream from the suction motor. The cyclone bin assembly may comprise the cyclone chamber and a dirt collection chamber. Dirty air from the dirty air inlet may circulate within the cyclone chamber and may exit the cyclone chamber to circulate within the dirt collection chamber. 
         [0131]    The cyclone bin assembly may also comprise a fine particle separator, to help separate relatively fine dirt particles from the dirty air. The fine particle separator may comprise a flow chamber through which the dirty air may circulate. Dirty air, carrying entrained fine dirt particles may flow from the cyclone chamber into the fine particle separator. Air exiting the fine particle separator may re-enter the cyclone chamber, and travel to the suction motor via a cyclone air outlet. 
         [0132]    The fine particle separator is configured so that air circulating in the flow chamber may travel at a relatively high velocity, and may travel faster than the air circulating within the cyclone chamber. To help increase the air flow velocity the cross-sectional area of the flow chamber, in the flow direction, may be varied, and preferably is reduced. Accelerating the dirty air to a relatively higher velocity may help disentrain fine dirt particles. 
         [0133]    The air outlet of the fine particle separator flow chamber may be configured to disrupt the flow of air exiting the flow chamber. Disrupting the flow of air, for example by introducing eddy currents and/or turbulence and/or directing the air away from the cyclone dirt outlet, may help separate fine dirt particles from the air stream. Separated dirt particles may fall into the dirt collection chamber. 
         [0134]    An advantage of this configuration may be a more efficient separation of fine dirt particles from the dirty air stream. Separating fine dirt particles from the dirty air stream in the fine particle separator may help prevent the fine dirt particles from continuing downstream from the cyclone bin assembly, and, for example, fouling the suction motor and/or a pre-motor filter. 
         [0135]    In accordance with this aspect, a surface cleaning apparatus comprises an air flow passage extending from a dirty air inlet to a clean air outlet. The air flow passage includes a suction motor. The surface cleaning apparatus may comprise a cyclone chamber in the air flow passage. The cyclone chamber may comprise a cyclone chamber first end and a cyclone chamber second opposed end, a cyclone air inlet, a cyclone air outlet and a cyclone chamber wall. The surface cleaning apparatus may comprise a dirt collection chamber having a dirt collection chamber first end, a dirt collection chamber second opposed end and an outer longitudinally extending sidewall. The outer longitudinally extending sidewall may have at least one recess provided therein. 
         [0136]    The recess may extend longitudinally. 
         [0137]    The recess may extend essentially from the dirt collection chamber first end to the dirt collection chamber second opposed end. 
         [0138]    The recess may comprise an outwardly extending concave surface. 
         [0139]    The dirt collection chamber may comprise at least two angularly spaced apart recesses. 
         [0140]    The recess may have an upstream side and a downstream side. The upstream side may extend sharply away from the outer longitudinally extending sidewall. 
         [0141]    The recess may have an upstream side and a downstream side. The upstream side may meet the outer longitudinally extending sidewall at a sharp corner. 
         [0142]    The recess may have an upstream side and a downstream side. The upstream side may extend away from the outer longitudinally extending sidewall at an angle. 
         [0143]    The angle may be between about 30° and about 75°, or more. 
         [0144]    The recess may have a depth between about 6 mm and about 15 mm, or more. 
         [0145]    According to yet another broad aspect of the teachings described herein, a surface cleaning apparatus comprises a cyclone chamber at least partially located within a dirt collection chamber such that at least a portion of the sidewall of the cyclone chamber is spaced from the sidewall of the dirt collection chamber to define a space therebetween in communication with the dirt outlet of the cyclone chamber. Preferably, the space is an annular region such that the sidewall of the dirt collection chamber extends all the way around the sidewall of the cyclone chamber. A support surface extends between the sidewall of the dirt collection chamber and the sidewall of the cyclone chamber. The support surface is configured to direct dirt towards the dirt collection area of the dirt collection chamber. 
         [0146]    The cyclone chamber may have a generally circular sidewall, and a generally annular gap may be formed between the cyclone chamber sidewall and a surrounding dirt collection chamber sidewall. The supporting surface may comprise at least one declined surface or ramp surface extending away from the cyclone chamber dirt outlet, to help prevent dirt particles from being retained on the support surface. 
         [0147]    An advantage of this configuration is that dirt particles may be more likely to fall into a lower portion of the dirt collection chamber, and may be less likely to be retained on the support surface. This may help facilitate emptying of the dirt collection chamber when a floor of the dirt collection chamber is opened. 
         [0148]    Preferably, the dirt collection chamber has a dirt collection surface that is opposed to and faces the end of the cyclone chamber opposed to the end of the cyclone chamber having the dirt outlet (e.g., the dirt collection surface may be below the cyclone chamber). Accordingly, the annular region of the dirt collection chamber may function as a passage from the cyclone dirt outlet to the dirt collection surface. If dirt particles collect on the support surface, then those particles may be re-entrained in air flowing in the annular region. 
         [0149]    A further advantage of this configuration is that the amount of dirt particles that collect on the support surface may be reduced and the amount of dirt particles re-entrained in the air stream returning to the cyclone chamber may be reduced, thereby increasing the separation efficiency of the cyclone chamber and dirt collection chamber. 
         [0150]    In accordance with this broad aspect, a surface cleaning apparatus comprises an air flow passage extending from a dirty air inlet to a clean air outlet. A suction motor may be provided in the air flow passage. A cyclone chamber may be provided in the air flow passage. The cyclone chamber may comprise a cyclone air inlet, a cyclone air outlet, a cyclone dirt outlet and a cyclone chamber wall. A dirt collection chamber may comprise a first end, a spaced apart opposed second end, a dirt inlet in communication with the cyclone dirt outlet, an annular portion that surrounds at least a portion of the cyclone chamber, an inner side adjacent the cyclone chamber, and an outer side spaced from the cyclone chamber and defined by a dirt collection chamber sidewall. A support surface may extend between the inner side and the outer side and may be configured to direct dirt towards a dirt collection area of the dirt collection chamber. 
         [0151]    The support surface may extending part way around the annular portion and may extend away from the dirt inlet. 
         [0152]    The support surface may have first and second ends that are angularly spaced apart around the cyclone chamber. The support surface may extend continuously away from the dirt inlet from the first end to the second end. 
         [0153]    The support surface may have first and second ends that are angularly spaced apart around the cyclone chamber and a mid-section. The support surface may extend continuously away from the dirt inlet from the mid-section to the first end and to the second end. 
         [0154]    The support surface may be curved and may have first and second ends that are angularly spaced apart around the cyclone chamber. The support surface may extend towards the dirt inlet from the first and second ends at an angle of up to 50° from a plane transverse to a longitudinal axis of the cyclone chamber. 
         [0155]    The support surface may extend towards the dirt inlet from the first and second ends at an angle from to 15° to 35° from a plane transverse to a longitudinal axis of the cyclone chamber. 
         [0156]    The dirt inlet may be provided at the first end and the support surface may be spaced from the dirt inlet towards the opposed second end. 
         [0157]    The cyclone dirt outlet may be the dirt collection chamber dirt inlet. 
         [0158]    The dirt collection chamber may comprise a dirt collection area that is provided at the opposed second end. 
         [0159]    The dirt inlet may be at an upper end of the dirt collection chamber and the dirt collection area may be in a lower portion of the dirt collection chamber. 
         [0160]    The cyclone chamber and the dirt collection chamber may be provided in a cyclone bin assembly that is removably mounted to the surface cleaning apparatus. 
         [0161]    The cyclone chamber may have a cyclone chamber first end and an opposed cyclone chamber second end and the cyclone dirt outlet is provided adjacent the cyclone chamber first end and the cyclone air inlet is provided at the opposed cyclone chamber second end. 
         [0162]    The cyclone chamber air outlet may be provided at the opposed cyclone chamber second end. 
         [0163]    The cyclone chamber first end may be an upper end of the cyclone chamber. 
         [0164]    The cyclone chamber first end may be provided proximate the first end of the dirt collection chamber. 
         [0165]    The cyclone chamber may have a cyclone chamber first end and an opposed cyclone chamber second end. The cyclone chamber may be provided proximate the first end of the dirt collection chamber. The opposed second end of the dirt collection chamber may be spaced from and may face the opposed cyclone chamber second end. 
         [0166]    Air may travel in the annular portion in a direction of rotation and the support surface may extend away from the dirt inlet in the direction of rotation. 
         [0167]    The support surface may have first and second ends that are angularly spaced apart around the cyclone chamber. The support surface may extend continuously away from the dirt inlet from the first end to the second end. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         [0168]    Reference is made in the detailed description to the accompanying drawings, in which: 
           [0169]      FIG. 1  is a perspective view of an embodiment of a surface cleaning apparatus; 
           [0170]      FIG. 2  is perspective cross sectional view of the cyclone bin assembly of the surface cleaning apparatus of  FIG. 1 , taken along line  2 - 2  in  FIG. 1 ; 
           [0171]      FIG. 3  is a side view of the cyclone bin assembly as shown in  FIG. 2 ; 
           [0172]      FIG. 4  is a perspective cross sectional view of the cyclone bin assembly as shown in  FIG. 2 , with its lid and dirt chamber floor open; 
           [0173]      FIG. 5  is a perspective view of the cyclone bin assembly of from the surface cleaning apparatus of  FIG. 1 , with its lid and dirt chamber floor open; 
           [0174]      FIG. 6  is a partial cut away view of the cyclone bin assembly of  FIG. 5 , with the lid and floor removed; 
           [0175]      FIG. 7 a -7 e    are alternate schematic representations of a fine particle separator; 
           [0176]      FIG. 8  is a side view of an alternate embodiment of a cyclone bin assembly that is usable with a surface cleaning apparatus; 
           [0177]      FIG. 9  is cross-sectional side view of the cyclone bin assembly of  FIG. 8 ; 
           [0178]      FIG. 10  is a top perspective view of the cyclone bin assembly of  FIG. 8 , with the lid removed; 
           [0179]      FIG. 11  is a bottom perspective view of the cyclone bin assembly of  FIG. 8 , with the dirt chamber floor removed; 
           [0180]      FIG. 12 a    is a schematic side view of the cyclone bin assembly of  FIG. 2 ; 
           [0181]      FIG. 12 b    is a schematic side view of the cyclone bin assembly of  FIG. 8 ; 
           [0182]      FIG. 12 c    is a schematic side view of an alternate embodiment of a cyclone bin assembly usable with a surface cleaning apparatus; 
           [0183]      FIG. 12 d    is a schematic side view of an alternate embodiment of a cyclone bin assembly usable with a surface cleaning apparatus; 
           [0184]      FIG. 13  is a perspective view of another example of a surface cleaning apparatus; 
           [0185]      FIG. 14  is a perspective view of another cyclone bin assembly with the lid and floor removed; 
           [0186]      FIG. 15  is a perspective sectional view taken along line  15 - 15  in  FIG. 14 ; and, 
           [0187]      FIG. 16  is a partial cut away view of the cyclone bin assembly of  FIG. 14 . 
       
    
    
     DETAILED DESCRIPTION 
       [0188]    Referring to  FIG. 1 , an embodiment of a surface cleaning apparatus  100  is shown. In the embodiment illustrated, the surface cleaning apparatus  100  is an upright surface cleaning apparatus. In alternate embodiments, the surface cleaning apparatus may be another suitable type of surface cleaning apparatus, including, for example, a hand vacuum, a canister vacuum cleaner, a stick vac, a wet-dry vacuum cleaner and a carpet extractor. 
       General Overview 
       [0189]    As exemplified in  FIG. 1 , a surface cleaning apparatus  100  includes a surface cleaning head  102  and an upper section  104 . 
         [0190]    The surface cleaning head  102  may be any suitable type of cleaning apparatus, including, for example a powered cleaning head having a rotating brush and a brushless cleaning head. The surface cleaning head  102  may be of any suitable configuration and may include at least one wheel or other rolling support to contact the surface being cleaned. 
         [0191]    In the illustrated example the surface cleaning head  102  includes a pair of rear wheels  106  and a pair of front wheels (optionally caster-type wheels, not shown) for rolling across a surface and a dirty air inlet  108  provided at the front end. 
         [0192]    If the surface cleaning apparatus is an upright surface cleaning apparatus, then the upper section  104  may be moveably connected to the surface cleaning head  102  by any means known in the art. The upper section  104  is moveable (e.g., pivotally mounted to the surface cleaning head  102 ) between a storage position and an in use position. An air flow passage extends from the dirty air inlet  108  to a clean air outlet  110 , which is preferably provided on the upper section  104 . The air flow passage may include any suitable combination of rigid conduits, flexible conduits, chambers and other features that may cooperate to direct a flow of air through the surface cleaning apparatus. The upper section  104  may be of various configurations. 
         [0193]    A handle  116  is preferably provided on the upper section  104  for manipulating the surface cleaning apparatus. The handle may be of any suitable configuration that may be grasped by a user. While illustrated as being positioned toward the top of the upper section  104 , the handle  116  may be provided at any other suitable location on the surface cleaning apparatus  100 . 
         [0194]    Referring to  FIGS. 1 and 2 , in the example illustrated, the upper section  104  comprises an air treatment housing  112  and a suction motor housing  114 , which is preferably positioned below air treatment housing  112 . The air treatment housing  112  houses an air treatment member, which is positioned in the air flow passage downstream from the dirty air inlet  108  to remove dirt particles and other debris from the air flowing through the air flow passage. The air treatment member  112  may be any suitable type of treatment member that includes any one or more of the features disclosed herein and may include, for example, a filter. In the illustrated example, the air treatment member comprises a cyclone bin assembly  118  comprising a cyclone chamber  120  and a dirt collection chamber  122 . The suction motor housing  114  is configured to house a suction motor (not shown). Preferably, as exemplified, the suction motor is in air flow communication with the air flow passage, downstream from the cyclone bin assembly  118 . The suction motor may be any suitable motor and may be selected based on a plurality of factors including, for example, suction strength, operating noise, power consumption and physical size. The housing  114  may be formed to accommodate the selected suction motor as well as mating with and optionally supporting the cyclone bin assembly  118 . 
         [0195]    It will be appreciated that, depending upon the aspects that are incorporated into a surface cleaning apparatus, some of the exemplified features may not be used or may be varied so as to be of any design known in the art. 
       Cyclone Bin Assembly 
       [0196]    Various different features for a cyclone bin assembly are disclosed herein. It will be appreciated that a cyclone bin assembly may use one or more of these features. Accordingly, a cyclone bin assembly may use one or more a dirt collection chamber having a variable cross sectional area in a direction transverse to the longitudinal axis of the dirt collection chamber, a fine particle separator, a rib provided in the dirt collection chamber, a reinforced floor construction for a dirt collection chamber, recessed columns in the dirt collection chamber and a ramped or inclined surface in the dirt collection chamber. Aside from containing one or more of these features, a cyclone bin assembly may be of any design. 
         [0197]    For example, the cyclone bin assembly may be of any suitable configuration, size and shape. The cyclone chamber may be configured in a plurality of different configurations, including, for example, an upright cyclone, an inverted cyclone and a horizontal or transverse cyclone. The dirt collection chamber may be configured to cooperate with a given cyclone chamber, as well as connecting with the rest of the surface cleaning apparatus. The cyclone chamber may be integrally formed with the dirt collection chamber, or optionally may be separable from the dirt collection chamber. 
         [0198]    Preferably, at least a portion of the cyclone bin assembly is removable from the upper section of the surface cleaning apparatus to help facilitate emptying of the dirt collection chamber. To help facilitate emptying and/or inspection at least one of, or both of the top and bottom of the cyclone bin assembly may be openable to provide access to the interiors of the cyclone chamber and/or the dirt collection chamber. 
         [0199]    Optionally, some or all of the cyclone bin assembly  118  may be formed from a transparent or semi-transparent material, such as plastic, so that a user may visually inspect the contents of the cyclone bin assembly  118 , for example the contents of the dirt collection chamber  122 , without having to open or disassemble the cyclone bin assembly  118 . This may also allow a user to inspect the interior of the cyclone bin assembly  118  while the surface cleaning apparatus  100  is in use. 
         [0200]    As exemplified in  FIGS. 2-6 , the cyclone chamber  120  may be an inverted cyclone and may be oriented with the dirt inlet at an upper end thereof. In other configurations, it will be appreciated that cyclone chamber  120  may be in a different orientation and may be of a different configuration. 
         [0201]    In the illustrated example the cyclone chamber  120  is bounded by a sidewall  124 , a first end wall  126  and a second end wall, or floor  128  that are configured to provide an inverted cyclone configuration. A lid  130  covers the top of the cyclone chamber  120 , and an inner surface of the lid  130  comprises the first end wall  126  of the cyclone chamber  120 . Preferably, the lid  130  is openable and/or detachable from the cyclone bin assembly  118  by any means known in the art. 
         [0202]    Opening the lid  130  may allow a user to access the interior of the cyclone chamber  120 , for example for cleaning. In the illustrated example, the lid  130  is pivotally connected to the cyclone bin assembly  118  by a hinge  132 , and is movable between a closed configuration ( FIG. 2 ) and an open configuration ( FIGS. 4 and 5 ). The lid  130  may be held in the closed position by any means known in the art, such as a releasable latch  134 . A handle  136  may be provided on the lid  130 . The handle  136  may be used to manipulate the cyclone bin assembly  118  when it is detached from the upper section  104 . 
         [0203]    Preferably, a tangential air inlet  138  is provided in the sidewall  124  of the cyclone chamber  120  and is in fluid communication with the dirty air inlet  108 . The tangential air inlet  138  may be of any suitable design and/or cross sectional area and may be provided at any suitable location along the sidewall  124  of the cyclone chamber  120 . Air flowing into the cyclone chamber  120  via the air inlet  138  may circulate around the interior of the cyclone chamber  120  and dirt particles and other debris may become disentrained from the circulating air. 
         [0204]    A dirt collection chamber may be provided to receive and retain dirt and debris that is separated from the dirty air flow via the cyclone chamber  120 . The dirt collection chamber may be any suitable configuration that may accommodate a given cyclone chamber, and may be formed from any suitable material, including, for example plastic and metal. At least a portion of the air circulating within the cyclone chamber may flow into and circulate within the dirt collection chamber when the cyclone bin assembly is in use. After having circulated within the dirt collection chamber, the air may flow back into the cyclone chamber and exit via the air outlet of the cyclone chamber. 
         [0205]    Optionally, the dirt collection chamber may be a unitary, integrally formed chamber. 
         [0206]    The dirt collection chamber may be of any suitable cross-sectional shape, and may have a varying cross-sectional shape along its height (as illustrated in  FIG. 1  and discussed subsequently) 
         [0207]    In the illustrated example, dirt collection chamber  122  is in communication with cyclone chamber  120 . Air with entrained dirt exits the cyclone chamber  120  via a cyclone dirt outlet  140  and enters the dirt collection chamber via a dirt collection chamber inlet. After circulating in the dirt collection chamber  122 , air may re-enter the cyclone chamber  118  via the dirt collection chamber inlet and the cyclone dirt outlet  140 . Preferably, the dirt collection chamber inlet and the cyclone dirt outlet  140  are the same element. For example, as exemplified, the cyclone dirt outlet  140  may be a slot formed between the sidewall  124  and the first end wall  126 . The slot  140  may also function as a dirt inlet for the dirt collection chamber  122 . 
         [0208]    Debris separated from the air flow in the cyclone chamber  120  may travel from the cyclone chamber  120 , through the dirt outlet  140  to the dirt collection chamber  122 . Preferably, the slot comprises a gap formed between the end of the sidewall  124  and end wall  126  that extends part way around the cyclone chamber  118  (e.g., up to 150°, preferably 30-150°, more preferably 60-120°). Alternatively, the dirt outlet  140  may be of any suitable configuration and may be provided at any suitable position on the cyclone chamber  120 . 
         [0209]    As exemplified, the cyclone chamber  118  may be positioned within the dirt collection chamber  122  and the dirt collection chamber  122  may comprise an annular portion surrounding part or the entire cyclone chamber  118 . Alternately, or in addition, the cyclone chamber  118  may be positioned such that a portion of the dirt collection chamber  122  is positioned opposed to and facing (e.g., below) the air exit end of the cyclone chamber  118 . The annular portion may merge into, and be contiguous with, the lower portion of the dirt collection chamber  122 . 
         [0210]    The cyclone chamber  120  extends along a longitudinal cyclone axis  156  ( FIG. 3 ). In the example illustrated, the longitudinal cyclone axis  156  is aligned with the orientation of the vortex finder  144 . The cyclone chamber  120  has a generally round cross-sectional shape and defines a cyclone chamber diameter  158 . Alternatively, the cyclone chamber  120  may have any suitable cross-sectional shape and configuration. 
         [0211]    Optionally, at least a portion of the cyclone chamber, for example a portion of a sidewall or an end wall, may be integral with portion of the dirt collection chamber sidewall, lid, cover or other feature (for example a fine particle separator as explained below). This may help reduce the overall side of the cyclone bin assembly  118  and/or may help facilitate manufacturing of the cyclone bin assembly. 
         [0212]    In the illustrated example, a rear a portion of the dirt collection chamber sidewall  152  is integral with a rear portion of the cyclone chamber sidewall  124 , and at least a portion of the second cyclone end wall  128  is integral with a portion of a first dirt collection chamber end wall  196 . 
       Air Exit Duct—Reinforced Floor Construction for a Dirt Collection Chamber 
       [0213]    In accordance with one aspect of this disclosure, which may be used by itself or with one or more other aspects set out herein, an end of a dirt collection chamber, preferably the floor, has an air flow conduit extend therethrough and the floor is reinforced by one or more support or stiffening members. 
         [0214]    For example, air exiting the cyclone chamber may flow through an air outlet through a portion of the dirt collection chamber. The air outlet may include any suitable type of conduit or air passage that is in air flow communication with the suction motor, including, for example, a down flow duct or other conduit. 
         [0215]    Air travelling through the air exit conduit may be travelling at a relatively high speed and may be swirling or otherwise turbulent. Such an air flow may tend to induce vibrations in the air exit conduit. Vibrations in the air exit conduit may tend to increase the noise generated by the cyclone bin assembly and/or may tend to damage components of the surface cleaning apparatus and/or may tend to disturb dirt that has settled out in the dirt collection chamber thereby facilitating the re-entrainment of such dirt. 
         [0216]    In accordance with this aspect, the air exit conduit and/or the dirt collection chamber may be configured to help reduce such air-induced vibrations. For example, the air exit conduit may be buttressed by one or more support or stiffening members. 
         [0217]    In the illustrated example, air may exit the cyclone chamber  120  via an air outlet  142 . As exemplified, the dirt collection chamber  122  is preferably positioned below the lower end wall  128  of the cyclone chamber in which air outlet  142  (e.g., vortex finder  144 ) is provided. In this orientation, the lower end wall  128  functions as a dirt collection surface. Preferably, the cyclone air outlet includes a vortex finder  144  extending into the cyclone chamber  120  and a passage that extends through a portion of the dirt collection chamber  122 , and preferably linearly through the dirt collection chamber, e.g. down duct  146 . Optionally, a screen  148  may be positioned over the vortex finder  144 . In some embodiments, the screen  148  and vortex finder  144  may be removable. The down duct  146  may comprise a generally cylindrical duct member extending through the interior of the dirt collection chamber  122 . Screen  148  may be any screen, shroud or the like known in the art. 
         [0218]    In use, the down duct  146  and/or end wall  128  of the cyclone chamber  118  may vibrate. The vibrations may produce an undesirable noise. Further, the vibrations may interfere with the dirt separation efficiency of the cyclone bin assembly. Vibrations induced by air flowing through down duct  146  may be transmitted to lower end wall  128  and may disturb dirt that has settled thereon. Once spaced from lower end wall  128 , the disturbed dirt may then be re-entrained in air travelling in the dirt collection chamber. Accordingly as exemplified, one or more stiffening ribs  150  may extend between the down duct  146  and the second end wall  128 . Providing stiffening ribs  150  may help reduce the vibration of the down duct  146  and/or second end wall  128  when the surface cleaning apparatus  100  is in use. Alternatively, or in addition to connecting to the second end wall  128 , stiffening ribs  150  may be configured to connect to the sidewall  152  and/or floor  154  of the dirt collection chamber  122 . 
         [0219]    The stiffening ribs  150  may be of any suitable shape and size, including, for example, triangular and rectangular. The ribs  150  may be formed from any suitable material, including, for example metal and plastic. Optionally, the stiffening ribs  150  may be integrally formed with the down duct  146  and/or portions of the cyclone chamber and/or dirt collection chamber. Alternatively, the ribs  150  may be separate members coupled to the down duct  146 . The ribs  150  may optionally be detachable or removable. 
         [0220]    The stiffening ribs  150  may be sized to help stabilize the down duct  146  while still allowing for a desired air flow circulation within the dirt collection chamber. 
         [0221]    Optionally, some of the stiffening ribs  150  may extend from the down duct  146  to the sidewall  152  of the dirt collection chamber. Others of the stiffening ribs  150  may extend from a fixed end adjacent the down duct  146  to a free end spaced apart from the down duct  146 . 
         [0222]    Optionally, the down duct  146  may be detachable from the second end wall  128  of the cyclone chamber  120 . If the down duct  146  is detachable from the second end wall  128 , the stiffening ribs  150  may also be detachable from the down duct  146 , or the second end wall  128  to help facilitate removal of the down duct  146 . Alternatively, the ribs  150  may remain attached to the cyclone bin assembly  118  (for example extending from the floor of the cyclone chamber) when the down duct is removed from the cyclone bin assembly  118 . 
         [0223]    Preferably, at least one portion of the dirt collection chamber  122  is openable and/or removable to help facilitate emptying of the dirt collection chamber. In the illustrated example the floor  154  of the dirt collection chamber  122  is openable. Opening the dirt collection chamber floor  154  may help facilitate emptying dirt and other debris from the dirt collection chamber  122 . In the example illustrated, the dirt collection chamber floor  154  is pivotally connected to the dirt collection chamber sidewall  152  by hinge  198 , and is pivotable between and open position ( FIGS. 3-5 ) and a closed position ( FIG. 2 ). The dirt collection floor  154  also comprises an air outlet aperture  200  that allows air from the down duct  146  to pass through the floor  154 , and into the suction motor housing  114 . Alternatively, any suitable type of releasable fastener may be used to secure the floor  154  to the sidewall  152 , including, for example, latches, pins, interference fit and clips. Optionally, sealing gaskets  202 , or other sealing members, may be provided around the perimeter of the floor  154  and around the air outlet aperture  200 , to help seal the dirt collection chamber  122  when the floor  154  is closed. 
       Fine Particle Separator 
       [0224]    In accordance with another aspect of this disclosure, which may be used by itself or with one or more other aspects set out herein, a fine particle separator is provided exterior to the cyclone chamber and in communication with the cyclone chamber via the cyclone chamber dirt outlet. 
         [0225]    Circulating air at a first speed within the cyclone chamber  120  may facilitate separation of a first portion of the dirt and debris from within the air flow. To help facilitate separation of a second, finer portion of the dirt and debris from the air flow it may be desirable to circulate the air at a second speed. Preferably the second speed is faster than the first speed, which may help disentrain finer dirt particles from the air flow. 
         [0226]    Optionally, the cyclone bin assembly may include a fine particle separator. The fine particle separator may be positioned outside the cyclone chamber and optionally, may surround at least a portion of the cyclone chamber. Portions of the cyclone chamber sidewalls may be integral with portions of the fine particle separator. 
         [0227]    To help increase the velocity of the air flow, the fine particle separator may have a smaller cross-sectional area than the cyclone chamber (in the direction of air flow). The cross-sectional area of the fine particle separator may be constant along its flow path, or may vary along the flow direction. Preferably, the cross-sectional area of the fine particle separator (in the flow direction) may decrease in the direction of the air flow, so that the area at an inlet of the fine particle separator is greater than an area at an outlet of the fine particle separator. This may help increase the velocity of the air flow as it travels through the fine particle separator. 
         [0228]    As exemplified, the cyclone bin assembly  118  includes a fine particle separator to help disentrain relatively fine dirt particles from the dirty air stream. In the example illustrated, the fine particle separator comprises an air recirculation chamber  160  surrounding the cyclone chamber  120  wherein air may rotate or swirl prior to re-entering the cyclone chamber  118 . Preferably, as exemplified, the air recirculation chamber  160  comprises a generally annular flow chamber  162 , part or all of which may be between the cyclone chamber sidewall  124  and an outer bin sidewall  164  (see for example  FIG. 6 ). It will be appreciated that the annular flow chamber may be positioned above the cyclone chamber  118  and that some or all of the annular flow chamber  162  may face the dirt outlet  140 . 
         [0229]    Optionally, the inner surface of the lid  130  may comprise an upper end wall  166  of the flow chamber  162 . In this configuration, a user may access the flow chamber  162  as well as the cyclone chamber  118  when the lid is opened, for example, for cleaning or inspection. Alternatively, the flow chamber  162  may have an upper end wall that is separate from the lid  130 . Air circulating within the air recirculation chamber flows in a rotational direction, generally about rotation axis  161 . 
         [0230]    Referring to  FIG. 3 , in the illustrated example, the flow chamber  162  surrounds the cyclone chamber  120 . Optionally, the height  170  of the flow chamber  162  may be selected so that it is approximately the same height  172  as the dirt outlet  140  of the cyclone chamber  120 . In this configuration, substantially all of the air exiting the cyclone chamber  120  may flow into the air recirculation chamber  160 . Alternatively, the flow chamber height  170  may be greater than or less than the dirt outlet height  172 , and optionally may extend the entire height  174  of the cyclone chamber  120 . This may adjust the amount of air exiting the cyclone chamber  120  that is drawn into the air recirculation chamber  160 . While illustrated in combination with a vertically oriented cyclone chamber  120 , the air recirculation chamber  160  may also be used with a cyclone chamber  120  oriented in another direction, including, for example, a horizontal cyclone chamber. 
         [0231]    The fine particle separator is preferably also in communication with the dirt collection chamber  122 . Accordingly, dirt collection chamber  122  may collect particulate matter separated by both the cyclone chamber and the fine particle separator. Preferably, the end of the fine particle separator closest to the dirt collection chamber  122  (e.g., the lower end) is continuous with the dirt collection chamber  122 . Alternatively, a separate dirt collection chamber may be provided to receive dirt separated by the fine particle separator. 
         [0232]    Referring to  FIG. 6 , when the surface cleaning apparatus is in use, at least a portion of the dirty air circulating within the cyclone chamber  120  may exit the cyclone chamber  118  via the dirt outlet  140  and travel into the flow chamber  162 , as illustrated using arrows  176 . The air entering the flow chamber  162  may carry entrained dirt particles. The air circulates in the annular flow chamber  162  before re-entering the cyclone chamber  118 . Concurrently, particulate matter separated in the cyclone chamber  118  may be ejected through dirt outlet  140  and pass into the dirt collection chamber  122 . 
         [0233]    Optionally, the cross sectional area of the annular flow chamber  162  in a plane transverse to the direction of rotation may be constant. Alternatively and preferably, as exemplified, the cross-sectional area of the flow chamber varies, and preferably decreases, in the downstream direction. For example, the flow area of a first upstream portion  178  of the flow chamber  162  is greater than the flow area of a second downstream portion  180  of the flow chamber  162 . In this configuration, when air flows from the first portion  178  into second portion  180 , the velocity of the air may increase. Preferably, the area may be selected so that air traveling through the second portion  180  of the flow chamber  162  is traveling at a higher velocity than the air circulating within the cyclone chamber  120 . Circulating the air at an increased velocity in the flow chamber  162  may help disentrain finer dirt particles then those that are disentrained in the cyclone chamber  118 . Air exiting the second portion  180  of the flow chamber passes through a second portion outlet  182 . Fine dirt particles disentrained in the air circulation chamber  160  may fall into the dirt collection chamber  122 . 
         [0234]    As exemplified in  FIGS. 5 and 6 , the flow area of the second portion  180  remains generally constant between the second portion inlet  184  and the second portion outlet  182 . Alternatively, the second portion  180  may be configured so that the flow area of the second portion varies between the inlet and outlet  184 ,  182 . For example, the second portion  180  may be configured so that the area at the outlet  182  is smaller than the area at the inlet  184 . This configuration may further increase the velocity of the air traveling from the inlet to the outlet  184 ,  182 . Alternatively, the second portion  180  may be configured so that the area at the inlet  184  is less than the area at the outlet  182 . 
         [0235]    The cross-sectional area of the second portion  180  may be varied using any suitable technique, including, for example, varying the spacing between the sidewalls of the second portion  180 , varying the thickness of one or more of the sidewalls and/or placing one or more inserts or other members within the flow area of the second portion  180 . To vary the cross-sectional area in the second portion  180  in the illustrated example, the thickness  186  of a portion of the cyclone chamber sidewall  124  may be varied, or the thickness  188  of the outer bin sidewall  164  may be varied, or both. Alternatively, instead of modifying the wall thicknesses  186 ,  188 , a separate ramp insert may be positioned within the second portion  180  of the flow chamber. Alternately, or in addition, the height  170  of the annular flow region  162  may be varied. 
         [0236]    Referring to  FIG. 7 a   , in a schematic representation of the second portion  180  of the flow chamber  162 , the thickness  186  of the cyclone chamber sidewall  124  at the inlet  184  is equal to the thickness  186  of the cyclone chamber sidewall  124  at the outlet  182 . Similarly, the thickness  188  of the sidewall  164  at the inlet  184  is equal to the thickness  188  of the sidewall  164  at the outlet  182 . While not shown, the height may remain constant such that the cross sectional area remains constant. 
         [0237]    In other embodiments, the wall thickness  186  at the outlet  182  may be different than the wall thickness  186  at the inlet  184 , as illustrated using schematic representations in  FIGS. 7 b -7 e   . Similarly, the wall thickness  188  may be varied.  FIGS. 7 e    and  10  illustrate embodiments in which a separate ramp member  189  is placed within the second portion  180  of the flow chamber  162 , instead of varying the wall thickness  186  of the cyclone chamber sidewall  124 . 
         [0238]    Disrupting the air flow as it exits the second portion, for example using an air contacting member, may help disentrain dirt particles. It may also be beneficial to temporarily divert the air flow exiting the second portion  180  away from the dirt inlet  140  to help disentrain further dirt particles which may help reduce the likelihood that dirt particles will be carried within the air flow when it re-enters the cyclone chamber  120 . Referring to  FIGS. 5, 6 and 10 , in the illustrated example, a portion of the cyclone chamber sidewall  124  adjacent the second portion outlet  182  may be configured to disrupt the flow of air exiting the second portion outlet  182  and\or direct the air flow away for the dirt inlet  140 . For example, the side wall or a ramp insert  189  may be provided at the outlet  182  to that the distance between the air flow region of portion  180  at outlet  182  and outlet  140  is increased. This may cause the air to make a sharper turn to return to the cyclone chamber, which may assist in separating finer dirt particles from the air flow. 
         [0239]    Alternately, or in addition, the cyclone chamber sidewall  124  may comprise a relatively sharp corner  190 , other any other suitable feature, which may also help disrupt the air flow  176 . Disrupting the air flowing past the corner  190  may help disentrain dirt particles from the air flow  176 , and may help urge the air flow  176   a  to re-enter the cyclone chamber  120  via the dirt outlet  140 . 
         [0240]    Optionally, the dirt outlet slot  140  may be configured to have a varying slot height  172  along its length. Varying the height of the dirt outlet slot  140  may alter the behaviour of the air flowing through the slot  140 , between the cyclone chamber  120  and the air recirculation chamber  160 , for example air flows  176  and  176   a . Alternatively, the dirt outlet need not be a single continuous slot, but can be any other suitable shape having one or more openings in the cyclone chamber sidewall. 
       Rib in the Dirt Collection Chamber 
       [0241]    In accordance with another aspect of this disclosure, which may be used by itself or with one or more other aspects set out herein, one or more ribs within the dirt collection chamber, and optionally extending between the dirt collection chamber sidewall and the cyclone chamber sidewall may be provided to help disentrain dirt from air circulating within the dirt collection chamber. 
         [0242]    The ribs are air contacting members and may be of any suitable construction so as to disrupt an air stream that may be travelling in the dirt collection chamber. Accordingly, the ribs may be substantially solid and/or may contain one or more apertures or other openings through which air may flow. The dirt collection chamber preferably comprises at least an annular section and at least one rib, and preferably one rib, is positioned in the annular portion. The rib may extend along a portion of the length of the annular portion and preferably along all or essential al of the entire length. 
         [0243]    The ribs may be formed from any suitable material and may be integrally formed with the cyclone bin assembly or provided as separate members. The ribs may be any suitable shape, and may be positioned as substantially vertical planar members, or positioned in any suitable orientation relative to the direction of air flow. 
         [0244]    As exemplified in  FIGS. 2-4 , the dirt collection chamber comprises an annular portion and optionally, one or more ribs  194  may extend between the cyclone chamber sidewall  124  and the dirt collection chamber sidewall  152 . The rib may be used with or without the fine particle separator described previously. 
         [0245]    Optionally, the ribs may extend only partway across the annular spaced between the sidewalls (having a free end spaced apart from one of the sidewalls  124 ,  152 ), but preferably extend completely across the annular space between the dirt collection chamber and cyclone sidewalls  152 ,  124 . Preferably, the rib  194  is positioned generally adjacent or proximate the dirt outlet  140  and more preferably, is positioned on the side of the dirt outlet  140  towards end wall  154  of the dirt collection chamber  122 . 
         [0246]    In this configuration, the rib is provided in the upper annular portion of the dirt collection chamber  122  and may be disposed below the optional fine particle separator if one is used. The rib  194  may accordingly impede the flow of the air flow circulating within an upper portion of the dirt collection chamber  122 , which may help separate dirt particles from the air stream and may reduce re-entrainment of separated particulate matter. Dirt particles contacting the rib  194  may be disentrained from the air flow and fall in the lower portion of the dirt collection chamber  122 . 
       Variable Dirt Collection Cross Sectional Area 
       [0247]    In accordance with another aspect of this disclosure, which may be used by itself or with one or more other aspects set out herein, the cross-sectional area of the dirt collection chamber may be varied along its height to help alter the characteristics of the air circulating within the dirt collection chamber. 
         [0248]    It will be appreciated that the dirt collection chamber is positioned exterior to the cyclone chamber and may be of various designs. As exemplified in  FIG. 3 , the dirt collection chamber  122  comprises an upper portion  204  and a lower portion  206 . The upper portion  204  is positioned adjacent the cyclone chamber  120  and comprises an upper portion sidewall  208  that at least partially surrounds the cyclone chamber  120 . The upper portion  204  may also comprise some or all of the air recirculation chamber  160 . In this configuration the upper portion  204  of the dirt collection chamber  122  has a generally round cross-sectional shape, and has an upper dirt chamber diameter  210 . 
         [0249]    As exemplified, the lower portion  206  of the dirt collection chamber is positioned generally below the cyclone chamber  120 . The lower portion  206  has a lower portion sidewall  212  with a generally round cross-sectional shape, and has a lower dirt chamber diameter  214 . In the illustrated configuration, the lower dirt chamber diameter  214  is greater than the upper dirt chamber diameter  210 . In this configuration, the dirt collection chamber  122  may be described as having a stepped out configuration. A transition surface  216  may connect the upper and lower portion sidewalls  208 ,  212 . In the illustrated example, the transition surface  216  comprises an angled wall. In other examples, the transition surface may have another configuration, including, for example a horizontal or curved wall. 
         [0250]    When air flows across the transition surface  216  from one portion to another (e.g. from the upper portion  204  to the lower portion  206  or from the lower portion  206  to the upper portion  204 ) the disruption in the air flow induced by the flowing from one portion to another may help disentrain dirt particles from the air flow. The features of the transition surface  216  and its intersection with sidewalls  208  and  212  may be selected to help improve dirt separation. 
         [0251]    The cross sectional area or diameter of the dirt collection chamber may be varied using a plurality of other sidewall configurations. For example, referring to  FIGS. 8-11 , another embodiment of a cyclone bin assembly  518  that may be used with a surface cleaning apparatus includes a cyclone chamber  520  and a dirt collection chamber  522 . Features of the cyclone bin assembly  518  that are analogous to features of cyclone bin assembly  118  are represented by like reference characters, indexed by  400 . Dirt collection chamber  522  includes an upper portion  604  and a lower portion  606 . In this embodiment, the upper dirt collection diameter  610  is greater than the lower dirt collection diameter  614 . In this configuration, the dirt collection chamber  522  may be described as having a stepped in configuration. 
         [0252]    By way of further example, referring to  FIG. 12 a   , a schematic representation of the stepped out cyclone bin assembly  118  illustrates a dirt collection chamber  122  with a lower portion diameter  214  that is greater than the upper portion diameter  210 .  FIG. 12 b   , is a schematic representation of the stepped in cyclone bin assembly  518 , in which the upper portion diameter  610  is greater than the lower portion diameter  614 . Other variable cross-section dirt collection chamber configurations may also be used. For example,  FIG. 12 c    is a schematic representation of another embodiment of a cyclone bin assembly  718 . The dirt collection chamber  722  in cyclone bin assembly  718  comprises an upper portion  804  having an upper portion diameter  810 , a lower portion  806  having a lower portion diameter  812  and an intermediate portion  840  having an intermediate portion diameter  842 . The upper and lower portion diameters  810 ,  814  are generally equal, and are both greater than the intermediate portion diameter  842 . In this configuration the dirt collection chamber  822  comprises two transition surfaces  816 .  FIG. 12 d   , is a schematic representation of another embodiment of a cyclone bin assembly  918 . The dirt collection chamber  922  in cyclone bin assembly  918  comprises an upper portion  1004  having an upper portion diameter  1010 , a lower portion  1006  having a lower portion diameter  1014  and an intermediate portion  1040  having an intermediate portion diameter  1042 . In this example, the upper and lower portion diameters  1010 ,  1014  are generally equal, and are both less than the intermediate portion diameter  1042 . Like dirt collection chamber  718 , dirt collection chamber comprises two transition surfaces  1016 . 
         [0253]    Changes in the cross-sectional area may be used to enhance the separation efficiency of the cyclone chamber and associated dirt collection chamber. By varying the transverse cross sectional area of the dirt collection chamber, the flow dynamics of the air in the dirt collection chamber may be varied and the amount of dirt that is disentrained from the air may be altered, or the amount of dirt that is re-entrained may be reduced. For example, if the cross sectional area of the portion of the dirt collection chamber distal to the dirt inlet (e.g., the lower portion  206 ) is less than the opposed portion (e.g. the upper portion with rib  194 ) adjacent the dirt inlet, then the air will slow down as it enters the upper portion. As the velocity decreases, the amount of dirt that may be re-entrained in the return airflow may decrease. If the cross sectional area of the portion of the dirt collection chamber distal to the dirt inlet (e.g., the lower portion) is greater than the opposed portion (e.g. upper portion) adjacent the dirt inlet, then the air will slow down as it enters the lower portion allowing more dirt to be disentrained. 
         [0254]    It will be appreciated that this aspect is preferably used with a cyclone having an upper dirt outlet and/or a fine particle separator and/or a dirt collection chamber having an annular portion. 
       Dirt Collection Chamber Wall Recesses 
       [0255]    In accordance with another aspect of this disclosure, which may be used by itself or with one or more other aspects set out herein, the sidewall of the dirt collection chamber may be configured to include one or more recesses. These recesses, (which may be referred to as bump-outs) are configured to help cause eddy currents to disrupt the air that may be circulating in the dirt collection chamber and thereby assist in disentraining dirt projections and other structure features. These recesses may extend substantially the entire length of the dirt collection chamber, or alternatively may be limited to select portions of the dirt collection chamber. The features may be integrally formed with the cyclone bin assembly, or provided as separate members. 
         [0256]    Referring to  FIGS. 5 and 6 , in the illustrated example, the dirt collection chamber sidewall  152  may comprise two recessed columns  220 , on opposing sides of the dirt collection chamber  122 . The recessed columns  220  may provide a discontinuity on the inner surface of the outer dirt collection chamber sidewall  152 , which may create eddy currents or other disruptions in the dirty air flow circulating within the dirt collection chamber  122 , represented by arrows  176   b . Preferably, the angle  222  formed at the intersection between the dirt collection chamber sidewall  152  and the upstream or leading edge  223  of the recessed column  220  walls is sufficient to create a relatively sharp corner, which may help disrupt the air flow. Preferably, the angle  222  is between about 30 and about 90°, and more preferably is between 45 and 90°. Disrupting the circulation of the dirty air passing over the recessed columns  220  may help disentrain dirt particles. In other embodiments, the dirt collection chamber  122  may comprise a different number of recessed columns  220  and the columns  220  may be formed in any suitable shape, including, for example square or rectangular cross-sectional shapes. 
         [0257]    The depth  224  of the recessed columns  220  may be selected to provide a sufficient depth such that an area with reduced or no air flow is created such that dirt particles may settle out and travel to the dirt collection floor. Collecting dirt particles within the recessed columns  220  may also help prevent re-entrainment of the dirt particles in the circulating air flow. Preferably, the depth  224 , represented using a dashed line to approximate the circumference of the uninterrupted sidewall  152 , is between about 6 and about 18 millimeters, or optionally may be greater than 18 millimeters or less than 6 millimeters. 
       Connecting Wall 
       [0258]    Referring to  FIGS. 9 and 11 , as an alternative to in addition to the stiffening ribs  550 , the down duct  546  may include a generally vertically oriented connecting wall  630  extending between the down duct  546  and the dirt collection chamber sidewall  552 . The connecting wall may be used by itself or with any one or more other aspects of this disclosure. The connecting wall  630  may be of any suitable size and configuration, and may be positioned in any suitable orientation. The connecting wall  630  may extend along substantially the entire height of the down duct  546 , or may be shorter than the down duct  546 . The connecting wall  630  may be positioned in any suitable location along the height of the down duct  546  and optionally may be configured to contact one or both of the cyclone chamber floor and the dirt collection chamber floor, or may be spaced apart from both floors. 
         [0259]    Preferably, as illustrated, the connecting wall  630  extends downward from the upper end wall  596 , and has a height  632  that is between about 5% and about 80% of the height  634  of the lower portion  606  of the dirt collection chamber  522 . More preferably, the connecting wall height  632  is between about 15% and 50% of the lower portion height  634 . The connecting wall  630  may impede the circulation of the dirty air flowing within the lower portion  606 . Impeding the circulation of the dirty air flow may help disentrain dirt particles from the dirty air flow. The disentrained particles may then be retained within the lower portion  606  when the circulating air re-enters the cyclone chamber  520 . The connecting wall  630  may also provide additional stiffness and vibration damping to the down duct  546 , as described above. 
       Ramped or Inclined Surface in the Dirt Collection Chamber 
       [0260]    In accordance with another aspect of this disclosure, which may be used by itself or with one or more other aspects set out herein, a dirt collection chamber may include a ramped or inclined surface in the dirt collection chamber. Dirt particles and other debris circulating within the dirt collection chamber may tend to settle or be deposited on any horizontal surfaces within the dirt collection chamber. Dirt that is resting on horizontal surfaces of the dirt collection chamber may become trapped or hung-up within the dirt collection chamber and may be difficult to empty from the chamber (for example by opening the floor of the chamber and allowing the dirt to fall our under the force of gravity). Accordingly, configuring such surfaces as inclined or ramped surfaces may help to reduce or minimize the surface area of any surfaces or other features that may trap or retain dirt particles. 
         [0261]    This aspect will be discussed with reference to  FIG. 13-16  which disclose another example of a surface cleaning apparatus  2100 . Surface cleaning apparatus  2100  includes a surface cleaning head  2102  and an upper section  2104 . The surface cleaning apparatus  2100  is generally similar to surface cleaning apparatus  100 , and like features are identified using like reference numerals indexed by  2000 . It will be appreciated that the surface cleaning apparatus of  FIGS. 13-16  is an exemplary embodiment and it may have any of the features discussed with respect to the exemplary embodiment of  FIGS. 1-12  and thee surface cleaning apparatus of  FIGS. 1-12  may have any of the features discussed with respect to the exemplary embodiment of  FIGS. 13-16 . 
         [0262]    The surface cleaning head  2102  includes a pair of rear wheels  2106  and a pair of front wheels (not shown) for rolling across a surface and a dirty air inlet  2108 . The upper section  2104  is moveably connected to the surface cleaning head  2102 . The upper section  2104  is moveable (e.g., pivotally mounted) between a storage position and an in use position. An air flow passage extends from the dirty air inlet  2108  to a clean air outlet  2110  on the upper section  104 . A handle  2116  is provided on the upper section  2104  for manipulating the surface cleaning apparatus  2100 . 
         [0263]    As exemplified in  FIGS. 13 and 14 , the upper section  2104  comprises an air treatment housing  2112  and a suction motor housing  2114 . The air treatment housing  2112  houses an air treatment member comprising at least one cyclone chamber and at least one dirt collection chamber, which is positioned in the air flow passage downstream from the dirty air inlet  2108  to remove dirt particles and other debris from the air flowing through the air flow passage. In the illustrated example, the air treatment member comprises a cyclone bin assembly  2118  comprising a cyclone chamber  2120  and a dirt collection chamber  2122 . The suction motor housing  2114  is configured to house a suction motor (not shown). The suction motor is in air flow communication with the air flow passage, preferably downstream from the cyclone bin assembly  2118 . 
         [0264]    In the illustrated example, the cyclone bin assembly  2118  is oriented vertically and the cyclone dirt outlet  2140  is provided at the upper end of the cyclone chamber  2120 . It will be appreciated that the cyclone bin assembly may be in other orientations when mounted to a surface cleaning apparatus and when in use. 
         [0265]    The cyclone chamber  2120  is bounded by a sidewall  2126 , a first (e.g., upper) end wall  2126  and a second end wall  2128 , (e.g., a floor). Preferably, as exemplified in  FIGS. 14-16 , the cyclone chamber  2120  is an inverted cyclone chamber. Accordingly, the dirt outlet  2140  is provided above the cyclone air inlet 
         [0266]    Preferably, as exemplified, the dirt outlet end of the cyclone chamber  2120  is openable. Accordingly, a lid  2130  may cover the top of the cyclone chamber  2120 , and an inner surface of the lid  2130  may comprise the first end wall  2126  of the cyclone chamber  2120 . Preferably, the lid  2130  is openable. Opening the lid  2130  may allow a user to access the interior of the cyclone chamber  2120 , for example for cleaning. In the illustrated example, the lid  2130  is pivotally connected to the cyclone bin assembly  2118  by a hinge  2132 , and is movable between a closed configuration and an open configuration. The lid  2130  may be held in the closed position by any suitable mechanism, including, for example a releasable latch  2134 . A handle  2136  is provided on the lid  2128 . The handle  2136  may be used to manipulate the cyclone bin assembly  2118  when it is detached from the upper section  2104 . Other methods of moveably mounting or removably mounting the lid  2128  may be used. 
         [0267]    Preferably, the cyclone air inlet comprises a tangential air inlet. Preferably, as exemplified, tangential air inlet  2138  is provided in the sidewall  2124  of the cyclone chamber  2120  and is in fluid communication with the dirty air inlet  2108 . Air flowing into the cyclone chamber via the air inlet may circulate around the interior of the cyclone chamber  2120  and dirt particles and other debris may become disentrained from the circulating air. 
         [0268]    Preferably, the dirt outlet  2140  comprises a gap provided between the sidewall  2124  of the cyclone chamber and first (upper) end wall  2126 . The gap may extend part way or all the way around sidewall  2124 . Preferably, as exemplified, the dirt outlet comprises a slot that extends part way around sidewall  122  between the end of sidewall  124  facing first end wall  2126  and first end wall  2126 . Debris separated from the air flow in the cyclone chamber  2120  may travel from the cyclone chamber  2120 , through the dirt outlet  2140  to the dirt collection chamber  2122 . 
         [0269]    Air may exit the cyclone chamber via an air outlet  2142 . In the exemplified embodiment, the cyclone chamber  2120  is inverted and the dirt collection chamber includes a portion spaced from and facing the air outlet end of the cyclone chamber. Accordingly, the air exit conduit extends at least part way through the dirt collection chamber. For example, reference may be made to  FIG. 14  and  FIG. 16  in which the lower portion  2168  of the dirt collection chamber  2122  positioned beneath the cyclone chamber  2120  has been removed. In this example, the cyclone air outlet includes a vortex finder  2144  extending into the cyclone chamber  2120 . Optionally, a screen may be positioned over the vortex finder. Optionally, the screen and vortex finder  2144  may be removable. 
         [0270]    A down duct  2144  extends from the vortex finder linearly through the lower portion  2168  of the dirt collection chamber  122 . The down duct  2146  comprises a generally cylindrical duct member and may extend in any direction through the interior of the dirt collection chamber  2122 . Optionally, the down duct  2146  may be detachable from the second end wall  2128 . 
         [0271]    The cyclone chamber  120  extends along a longitudinal cyclone axis  2156 . In the example illustrated, the longitudinal cyclone axis  2156  is aligned with the orientation of the vortex finder  2144 . 
         [0272]    The dirt collection chamber  2122  comprises a sidewall  2152 , a first (upper) end wall  150  and an opposing second end wall, or floor  2154 . The first end walls of the cyclone chamber and the dirt collection chamber may be configured to be openable concurrently, e.g., they may be integrally formed. Alternately, or in addition, the second end walls of the cyclone chamber and the dirt collection chamber may be configured to be openable concurrently, e.g., they may be integrally formed with each other. 
         [0273]    Referring to  FIG. 13 , the floor  2154  of the dirt collection chamber  2122  is openable. Opening the dirt collection chamber floor  2154  may help facilitate emptying dirt and other debris from the dirt collection chamber  2122 . In the example illustrated, the dirt collection chamber floor  2154  is pivotally connected to the dirt collection chamber sidewall  2152  by a hinge, and is pivotable between and open position and a closed position. The dirt collection floor  2154  also comprises an air outlet aperture that allows air from the down duct to pass through the floor  2154 . Optionally, sealing gaskets, or other sealing members, may be provided around the perimeter of the floor  2154  and around the air outlet aperture, to help seal the dirt collection chamber  2122  when the floor  2154  is closed. 
         [0274]    As exemplified, the dirt collection chamber  2122  has a portion adjacent the cyclone dirt outlet  2140  that is preferably annular in shape (e.g., the upper annular portion) and a second spaced apart portion extending across the outer surface of the air exit end of the cyclone chamber (lower portion  2168 ). Preferably, the portions are contiguous. 
         [0275]    The dirt collection chamber  2122  has a dirt collection chamber dirt inlet  2153  that is in communication with the cyclone dirt outlet  2140 . Preferably, the dirt inlet  2153  is the dirt outlet  2240  of the cyclone chamber  2120 . 
         [0276]    In the illustrated example, the cyclone chamber  2120  is nested towards the rear of the dirt collection chamber  2122  (relative to the direction of travel of the surface cleaning apparatus  2100 ), and a generally annular space  2250  is defined between the cyclone chamber sidewall  2124  and the dirt collection chamber sidewall  2152 . The annular space  2250  may have a constant width or the width may vary. Further, the annular space may surround the entire height of the cyclone chamber  2120  or any part or portion thereof. In other configurations, the space  2250  may have any other suitable shape and need not be curved or annular. 
         [0277]    A support member, for example a support surface, may be provided to help support the cyclone chamber  2120  within the cyclone bin assembly. The support member may be any suitable combination of structural members that are configured to help connect the cyclone chamber to the dirt collection chamber, and hold the relative spacing between these chambers while the surface cleaning apparatus is in use. 
         [0278]    In the illustrated example, the support surface comprises a connecting wall  2252  that is provided in the annular space  2250  between the cyclone chamber sidewall  2124  and the dirt collection chamber sidewall  2152 , rearward of the cyclone chamber  2120 . Connecting wall  2252  surrounds a portion of the cyclone chamber  2120 , and in the illustrated example surrounds approximately 50% of the cyclone chamber  2120 . In other examples the connecting wall  2252  may surround more than or less than 50% of the cyclone chamber  2120 . 
         [0279]    When the surface cleaning apparatus is in use, a portion of the dirty air in the cyclone chamber  2120  may flow out of the dirt outlet  2140  and circulate within the dirt collection chamber  2122  in a rotation direction, as illustrated using arrows  2254 . A portion of this air may flow through the annular space  2250  behind the cyclone chamber  2120 . Dirt particles entrained with the air circulating through annular space  2250  may become disentrained from the air flow and may settle on the upper surface  2256  of the connecting wall  2252 . 
         [0280]    In accordance with this aspect of the disclosure, the connecting wall  2252  is preferably configured to help shed the dirt particles that settle on the connecting wall  2252 , and to urge the dirt particles toward the lower portion  2168  of the dirt collection chamber  2122 . Guiding the dirt particles toward the lower portion  2168  of the dirt collection chamber  2122  may help facilitate the collection of dirt and debris in the lower portion  2168  of the dirt collection chamber  2122 , which may help facilitate emptying of the dirt collection chamber  2122 . It may also help prevent dirt particles from being retained on the upper surface  2256  of the connecting wall  2252 . Preferably, the connecting wall  2252  does not comprise horizontal surfaces that may retain dirt particles when the surface cleaning apparatus  2100  is in an upright position (for example see  FIG. 13 ). 
         [0281]    The connecting wall  2252  may be of any suitable shape and configuration, and may include any suitable combination of features to help inhibit the accumulation of dirt and debris on the connecting wall  2252 . In the illustrated example, the connecting wall  2252  has a high point  2260  adjacent the tangential air inlet  2138  that is at a higher elevation than the first and second ends  2262 ,  2264 , thereby forming first and second ramp surfaces  2266 ,  2268 . In this configuration, the high point  2260  of the connecting wall is intermediate the first and second ends  2262  and  2264 , and is offset relative to a lateral centre line  2270  cyclone chamber. Alternatively, the high point  2260  of the connecting wall  2252  may be aligned with the centre line  2270 . 
         [0282]    First and second ramp surfaces  2266 ,  2268  slope generally downwardly from the high point  2260  toward the first and second ends  2262 ,  2264 , respectively. In this configuration, the first and second ends  2262 ,  2264  are positioned at the points of lowest elevation on the connecting wall  2252 . Providing inclined ramp surfaces  2266 ,  2268  may help urge dirt particles settling on the ramp surfaces  2266 ,  2268  to move toward the corresponding ends  2262 ,  2264  of the connecting wall  2252 , and fall into lower portion of the dirt collection chamber  2122 . The slope of the ramp surfaces  2266  and  2268  may be constant along their lengths, or may vary. 
         [0283]    The first ramp surface  2266  is preferably a generally smooth surface extending from the high point  2260  to the first end  2262 . The second ramp surface  2268  may comprise a portion of the tangential air inlet sidewall  2272  and comprises a kinked region  2274  where the air inlet sidewall  2272  joins with the connecting wall  2252 . Providing a kinked region  2274 , or other type of discontinuity in the ramp surface  2268 , may introduce eddy currents or other flow disturbances in the dirty air flow circulating within the annular space  2250 . Introducing disturbances in the air flow may help disentrain dirt particles from the air flow. Other surface features may also be provided on the ramp surfaces  2266  and  2268 . 
         [0284]    Optionally, instead of positioning the high point  2260  of the connection wall intermediate the first and second ends  2262  and  2264 , the high point  2260  may be positioned at one of the ends  2262 ,  2264  of the connecting wall  2252 . For example, the connecting wall  2252  may be configured so that the first end  2262  is the point of highest elevation  2260  and the second end  2264  is the point of lowest elevation, so that the connecting wall  2252  may slope generally downward from the first end  2262  to the second end  2264 , or vice versa. Preferably, at least one of the ends  2262 ,  2264  of the connecting wall is positioned at the point of lowest elevation of the connecting wall  2252 . Positioning at least one of the ends  2262 ,  2264  at the point of lowest elevation may help prevent low points or recesses along the length of the connecting wall  2252 , which may trap dirt particles, from being formed between the high point  2260  and the ends  2262 ,  2264  of the connecting wall. 
         [0285]    The ramp surface may be sloped or declined at an angle between about 5 degrees to about 80° relative to a plane that is perpendicular to the cyclone axis  2156  (for example a horizontal plane), preferably between about 5° and about 50° and more preferably between about 15° and about 35°. The slope of the ramped surfaces  2266 ,  2268  is preferably generally constant along their length. However, the slope of the ramped surfaces  2266 ,  2268  may vary along the lengths of the surfaces  2266 ,  2268 , so that a given ramped surface  2266  or  2268  may comprise relatively steeper and relatively flatter portions. 
         [0286]    In the example illustrated, a portion of the connecting wall  2252  is integral with the tangential air inlet sidewall  2272 . Accordingly, it will be appreciated that the connecting wall may form, e.g., an upper surface of the cyclone air inlet. Alternatively, the tangential air inlet sidewall  2272  may be separate from the connecting wall  2252  and/or may not pass through the dirt collection chamber  2120 . 
         [0287]    It will be appreciated that the following claims are not limited to any specific embodiment disclosed herein. Further, it will be appreciated that any one or more of the features disclosed herein may be used in any particular combination or sub-combination, including, without limitation, a dirt collection chamber with a variable diameter or cross sectional area, the fine particle separator, an annular dirt collection chamber with a rib or baffle, reinforcing ribs for a cyclone chamber floor, a down flow duct and a recess in the outer sidewall of the dirt collection chamber and/or a connecting wall. 
         [0288]    What has been described above has been intended to be illustrative of the invention and non-limiting and it will be understood by persons skilled in the art that other variants and modifications may be made without departing from the scope of the invention as defined in the claims appended hereto.