Dual-stage cyclonic air separator

Abstract

A dual-stage cyclonic separator is provided for separating debris from air in a bagless surface cleaning apparatus, along with a bagless surface cleaning apparatus incorporating such a cyclonic separator. A debris collection device used with a bagless surface cleaning apparatus is also provided, along with a method of separating debris from air using a bagless surface cleaning apparatus.

What is claimed is: 
     
         1 . A dual-stage cyclonic separator for separating debris from air in a bagless surface cleaning apparatus, comprising:
 a cyclonic frustum comprising:
 a frustum wall having an outer frustum wall for directing a preliminary centrifugal airflow thereabout and an inner frustum wall for directing a ultimate centrifugal airflow therein, with the frustum wall tapering generally inwardly from a frustum extent disposed adjacent a frustum extent opening toward an opposed frustum extent disposed adjacent a frustum egress; 
 a cylindrical wall depending upwardly from an interface with the frustum extent opening and terminating in a cylindrical ingress; and 
 an airflow turret provided at the cylindrical ingress that facilitates transition of the preliminary centrifugal airflow to the ultimate centrifugal airflow; 
   a debris collection cup comprising:
 a cup wall having an outer cup wall that, together with a debris collection device and the outer frustum wall, provides a coarse debris collection area within which debris is deposited by the preliminary centrifugal airflow, and an inner cup wall that provides a fine debris collection area within which debris is deposited by the ultimate centrifugal airflow, with at least a portion of the opposed frustum extent depending inwardly into the debris collection cup such that the ultimate centrifugal airflow deposits debris directly within the fine debris collection area; 
   a cyclonic sieve having a sieve wall coextensive with a turret extent for placement adjacent the airflow turret and an opposed debris restriction extent, with the sieve wall having a continuous portion for directing the preliminary centrifugal airflow about the frustum wall and a louvered portion for delivering airflow to the airflow turret, and with the louvered portion including a plurality of apertures; and   an airflow outlet configured to deliver air from the debris collection device after depositing debris in the fine debris collection area.   
     
     
         2 . The cyclonic separator of  claim 1 , wherein the airflow turret comprises at least two similarly configured and evenly spaced sails that are circumferentially arranged relative to the cylindrical ingress, with each sail having a guide surface to guide incoming air from the preliminary centrifugal airflow toward the cylindrical ingress. 
     
     
         3 . The cyclonic separator of  claim 2 , wherein the airflow turret comprises five sails and the guide surface of each sail exhibits a generally radial profile that includes an impact surface of predetermined concavity against which the incoming air strikes and a terminal restraining edge for piloting the incoming air toward the cylindrical ingress. 
     
     
         4 . The cyclonic separator of  claim 3 , wherein the terminal restraining edge includes a lead surface that leads the incoming air toward the impact surface, and a trail surface that pilots the incoming air toward the cylindrical ingress during the transition of the preliminary centrifugal airflow to the ultimate centrifugal airflow. 
     
     
         5 . The cyclonic separator of  claim 4 , wherein the lead surface of the terminal restraining edge leads the incoming air that enters through an adjacent velocity slot provided between adjacent sails, with the velocity slot including an entry ramp of predetermined camber configured to deliver the preliminary centrifugal airflow from the coarse debris collection area toward the cylindrical ingress. 
     
     
         6 . The cyclonic separator of  claim 5 , wherein the airflow turret includes a turret seating flange having an upper turret seat and a lower turret seat, and the cyclonic sieve includes a sieve seating flange having an upper sieve seat and a lower sieve seat, with the cyclonic sieve positioned relative to the cyclonic frustum such that the upper sieve seat is disposed adjacent the lower turret seat. 
     
     
         7 . The cyclonic separator of  claim 5 , wherein the sieve wall is positioned relative to the debris collection device such that dirty air that enters the debris collection device tangentially impinges the continuous portion of the sieve wall. 
     
     
         8 . The cyclonic separator of  claim 7 , wherein:
 each guide surface exhibit s a radius of about 38°;   each lead surface exhibits a radius of about 14°;   each trail surface exhibits a radius of about 14°;   each velocity slot exhibits a cross-sectional area in a range from about 120 mm 2  to about 130 mm 2 ; and   each entry ramp exhibits a grade of about 48°.   
     
     
         9 . The cyclonic separator of  claim 8 , wherein at east one of the apertures in the louvered portion of the sieve wall has at least one of a rounded upstream edge and a rounded downstream edge past which the preliminary centrifugal airflow is delivered to the velocity slot. 
     
     
         10 . The cyclonic separator of  claim 9 , wherein the sieve wall exhibits a generally frustoconical geometry and the apertures are provided in a predetermined pattern along the louvered portion thereof. 
     
     
         11 . The cyclonic separator of  claim 8 , wherein debris that is not deposited in the coarse debris collection area by the preliminary centrifugation airflow is deposited by the ultimate centrifugal airflow into the fine debris collection area through the frustum egress. 
     
     
         12 . The cyclonic separator of  claim 11 , wherein an optional sifter is disposed near the frustum egress and configured to direct debris that is deposited from the frustum through the frustum egress into the fine debris collection area. 
     
     
         13 . The cyclonic separator of  claim 8 , wherein the airflow outlet is provided in a support member that is disposed adjacent the upper turret seat and configured to direct outgoing air from the cyclonic separator. 
     
     
         14 . The cyclonic separator of  claim 8 , further comprising a debris restriction flange provided adjacent the debris restriction extent of the cyclonic sieve and configured to deflect debris in the preliminary centrifugal airflow into the course debris collection area. 
     
     
         15 . A bagless surface cleaning apparatus, comprising:
 a base suction unit;   an apparatus handle; and   a main body provided intermediate the base suction unit and the apparatus handle and operably supporting a debris collection device thereby; and   the cyclonic separation system of  claim 1  with the sieve wall positioned relative to the debris collection device such that dirty air that enters the debris collection device tangentially impinges the continuous portion of the sieve wall.   
     
     
         16 . The bagless surface cleaning apparatus of  claim 15 , wherein at least two similarly configured and evenly spaced sails are provided in the turret, with each sail comprising:
 a guide surface to guide incoming air from the preliminary centrifugal airflow toward the cylindrical ingress, with the guide surface of each sail including an impact surface of predetermined concavity against which the incoming air strikes and a terminal restraining edge for piloting the incoming air toward the cylindrical ingress, and with the terminal restraining edge including a lead surface that leads the incoming air toward the impact surface, and a trail surface that pilots the incoming air toward the cylindrical ingress during the transition of the preliminary centrifugal airflow to the ultimate centrifugal airflow.   
     
     
         17 . The bagless surface cleaning apparatus of  claim 16 , wherein the lead surface of the terminal restraining edge leads the incoming air that enters through an adjacent velocity slot provided between adjacent sails, with the velocity slot including an entry ramp of predetermined camber configured to deliver the preliminary centrifugal airflow from the coarse debris collection area toward the cylindrical ingress. 
     
     
         18 . A debris collection device used with a bagless surface cleaning apparatus to separate debris from air, comprising:
 a debris collection canister;   a debris collection cover coupled with the debris collection canister;   a centrifugal separation system according to  claim 1     
     
     
         19 . The debris collection device of  claim 18 , further comprising at least one of:
 a handle formed on at least one of the debris collection canister and the debris collection cover, with the handle configured to be grasped by a user for removal of the debris collection device from, and replacement of the debris collection device in, the cleaning apparatus and for carrying the debris collection device upon removal from the cleaning apparatus;   an actuatable flapper provided at or adjacent a collective debris release outlet from which accumulated debris is released from the course debris collection area and the fine debris collection area; and   a controlled tension apparatus that controls an angular range of movement of the flapper for controllable release of accumulated debris from the collective debris release outlet.   
     
     
         20 . A method of separating debris from air using a bagless surface cleaning apparatus, comprising:
 providing the cyclonic separator of  claim 1  in a debris collection device operably mounted in the cleaning apparatus;   positioning the cyclonic separator so that dirty air that enters the debris collection device tangentially impinges the continuous portion of the sieve wall;   positioning the cyclonic sieve so that the preliminary centrifugal airflow traverses the louvered portion of the sieve wall toward the cylindrical ingress during the transition of the preliminary centrifugal airflow to the ultimate centrifugal airflow; and   configuring the airflow outlet to direct separated air from the cyclonic separator.