Vacuum cleaner with exhaust tube having an increasing cross-sectional area

Abstract

A vacuum cleaner includes a cyclonic chamber having an inlet for introducing airflow for circulation around a central axis of the cyclonic chamber. A filter chamber is positioned downstream of the cyclonic chamber and has a wall. A filter is positioned in the filter chamber. An exhaust tube extends along the central axis into the cyclonic chamber. The exhaust tube includes an inlet portion receiving the airflow from the cyclonic chamber and an outlet portion directing the airflow toward the filter chamber and the filter. The filter is in close proximity to the outlet portion. The cross-sectional area of the outlet portion increases in the downstream direction to reduce the speed of the airflow passing into the filter chamber and to evenly distribute the airflow passing through the outlet opening across the filter.

What is claimed is: 
     
         1 . A vacuum cleaner comprising:
 a cyclonic chamber having an inlet for introducing airflow for circulation around a central axis of the cyclonic chamber;   a filter chamber positioned downstream of the cyclonic chamber and having a wall;   a filter positioned in the filter chamber; and   an exhaust tube extending along the central axis into the cyclonic chamber, the exhaust tube including an inlet portion receiving the airflow from the cyclonic chamber and an outlet portion directing the airflow toward the filter chamber and the filter, which is in close proximity to the outlet portion, wherein the outlet portion includes an outlet opening on the wall of the filter chamber upstream of the filter, wherein the cross-sectional area of the outlet portion increases in the downstream direction to reduce the speed of the airflow passing into the filter chamber and to evenly distribute the airflow passing through the outlet opening across the filter, and wherein the exhaust tube defines a substantially constant diameter over a portion of its length.   
     
     
         2 . The vacuum cleaner of  claim 1 , wherein a gap distance is defined between the wall and the filter, and wherein the gap distance is at least 5% of the diameter. 
     
     
         3 . The vacuum cleaner of  claim 2 , wherein the gap distance is between 5% and 50% of the diameter. 
     
     
         4 . The vacuum cleaner of  claim 2 , wherein the gap distance is between 5% and 25% of the diameter. 
     
     
         5 . The vacuum cleaner of  claim 2 , wherein the gap distance is between 5% and 10% of the diameter. 
     
     
         6 . The vacuum cleaner of  claim 1 , wherein outlet portion is defined by an arcuate wall rotated about the central axis, and wherein the arcuate wall defines a radius of at least 15% of the diameter. 
     
     
         7 . The vacuum cleaner of  claim 6 , wherein the radius is between 15% and 50% of the diameter. 
     
     
         8 . The vacuum cleaner of  claim 6 , wherein the radius is between 15% and 25% of the diameter. 
     
     
         9 . The vacuum cleaner of  claim 1 , wherein the outlet portion increases from the diameter to an outlet opening diameter on the wall, the outlet opening diameter being approximately twice the diameter. 
     
     
         10 . The vacuum cleaner of  claim 1 , wherein the wall and the exhaust tube are integrally formed as a single molded component. 
     
     
         11 . The vacuum cleaner of  claim 1 , wherein the wall is a bottom wall of the filter housing, and wherein the filter chamber includes an upwardly-directed sidewall, wherein a perimeter of the filter is supported by the sidewall above the bottom wall to provide a gap between the bottom wall and a bottom of the filter. 
     
     
         12 . The vacuum cleaner of  claim 11 , wherein the bottom wall, the sidewall, and the exhaust tube are integrally formed as a single molded component. 
     
     
         13 . The vacuum cleaner of  claim 1 , further comprising a first stage cyclonic chamber, and wherein the cyclonic chamber is a second stage cyclonic chamber downstream of the first stage cyclonic chamber. 
     
     
         14 . The vacuum cleaner of  claim 1 , further comprising a motor-driven fan configured to create the airflow, the filter being located upstream of the motor-driven fan. 
     
     
         15 . The vacuum cleaner of  claim 1 , wherein the inlet portion of the exhaust tube includes a flow straightener in the form of intersecting vanes. 
     
     
         16 . A vacuum cleaner, comprising:
 a housing having a central axis and an outer wall extending from a first end to a second end, the outer wall defining an air inlet between the first end and the second end;   a lid assembly selectively, movably coupled to the first end, the housing and lid assembly at least partially defining a dirt collection chamber;   a shroud disposed within the housing, the shroud and the outer wall at least partially defining a first cyclonic separation region;   a cyclone body at least partially disposed within the shroud, the cyclone body at least partially defining a second cyclonic separation region;   an exhaust assembly coupled to the second end, the exhaust assembly including
 an inlet portion extending into and receiving air from the second cyclonic separation region, the inlet portion having a substantially uniform cross sectional area, and 
 an outlet portion downstream of the inlet portion, the outlet portion having an increasing cross-sectional area in the downstream direction; 
   a cover member coupled to the exhaust assembly downstream of the outlet portion, the cover member and exhaust assembly defining a filter chamber;   a filter member disposed in the filter chamber and separated from the exhaust assembly outlet portion by an air gap, the filter member receiving a substantially evenly distributed airflow from the exhaust assembly outlet portion.   
     
     
         17 . The vacuum cleaner of  claim 16 , wherein the exhaust assembly inlet portion includes a flow straightener in the form of intersecting vanes. 
     
     
         18 . The vacuum cleaner of  claim 16 , wherein the shroud, the cyclone body, and the exhaust assembly are substantially co-axially disposed along the central axis. 
     
     
         19 . The vacuum cleaner of  claim 18 , wherein the outlet portion is defined by an arcuate wall rotated about the central axis. 
     
     
         20 . The vacuum cleaner of  claim 16 , further comprising a motor-driven fan configured to create the airflow, the filter member being located upstream of the motor-driven fan.