Surface treatment applicance, a filter and components therefor

Abstract

A cyclone filtration assembly unit is described. The unit is configured to mount in a vacuum cleaner, and includes a housing having a housing inlet for a dirty air stream and a housing outlet for a filtered air stream; one or more cyclone separators mounted in the housing, each of the one or more cyclone separators comprising one or more cyclone separator inlets, at least one dirt outlet, and at least one clean air outlet in fluid communication with the housing outlet; and one or more injector units configured to deliver an airstream of clean air from outside the housing and dirty air from inside the housing to the one or more cyclone separator inlets, the injector unit comprising: a diffuser duct having an inlet end in fluid communication with the housing inlet to introduce dirty air from the housing inlet to the cyclone separator inlet, and an injector tube configured to inject clean air into the diffuser duct adjacent the inlet end, the injector tube being in fluid communication with a housing aperture at an inlet end to introduce clean air from outside the housing to the diffuser duct.

1 . A cyclone filtration assembly unit for mounting in a vacuum cleaner, the cyclone filtration assembly unit including:
 a housing having a housing inlet for a dirty air stream and a housing outlet for a filtered air stream;   one or more cyclone separators mounted in the housing, each of the one or more cyclone separators comprising one or more cyclone separator inlets, at least one dirt outlet, and at least one clean air outlet in fluid communication with the housing outlet; and   one or more injector units configured to deliver an airstream of clean air from outside the housing and dirty air from inside the housing to the one or more cyclone separator inlets, the injector unit comprising:
 a diffuser duct having an inlet end in fluid communication with the housing inlet to introduce dirty air from the housing inlet to the cyclone separator inlet, and 
 an injector tube configured to inject clean air into the diffuser duct adjacent the inlet end, the injector tube being in fluid communication with a housing aperture at an inlet end to introduce clean air from outside the housing to the diffuser duct. 
   
     
     
         2 . The cyclone filtration assembly unit in accordance with  claim 1  wherein the diffuser duct is a venturi arrangement, wherein adjacent the injector tube there is a throat portion being a restriction in the diameter of the diffuser duct. 
     
     
         3 . The cyclone filtration assembly unit in accordance with  claim 1  wherein the diffuser duct includes an outlet in fluid communication with an associated cyclone separator, the diffuser duct being configured to mix the clean airstream with the dirty air stream. 
     
     
         4 . (canceled) 
     
     
         5 . The cyclone filtration assembly unit in accordance with  claim 1  wherein the tortuous path is a helix. 
     
     
         6 . The cyclone filtration assembly unit in accordance with  claim 1  wherein a valve is provided in fluid communication with the injector tube to control clean air inlet flow therethrough. 
     
     
         7 . The cyclone filtration assembly unit in accordance with  claim 6  further including an electronic controller for the valve, the electronic controller being configured to respond to changes in pressure in the diffuser duct. 
     
     
         8 . The cyclone filtration assembly unit in accordance with  claim 6  further including a valve closure element operatively connected to a pressure-responsive element that is responsive to changes in pressure in the diffuser duct. 
     
     
         9 . The cyclone filtration assembly unit in accordance with any one of  claim 2  wherein the venturi throat portion or venturi restriction and the valve are integrally-formed so as to provide a variable choke in the diffuser duct and fresh air injection with a response to reductions in pressure in the diffuser duct. 
     
     
         10 . The cyclone filtration assembly unit in accordance with  claim 9  further including a biasing element to bias the valve closure element, the biasing element disposed in a clean air duct. 
     
     
         11 . The cyclone filtration assembly unit in accordance with of  claim 1  wherein the injector tube is angled relative to the diffuser duct so as to provide accelerated the dirty air in the diffuser duct. 
     
     
         12 . The cyclone filtration assembly unit in accordance with  claim 6  wherein the throat section of the diffuser duct is variable in internal diameter in response to changes in pressure in the diffuser duct. 
     
     
         13 . The cyclone filtration assembly unit in accordance with  claim 6  wherein the throat section of the diffuser duct includes flexible walls so as to vary the internal cross section area of the diffuser duct. 
     
     
         14 . The cyclone filtration assembly unit in accordance with  claim 2  wherein a regulator is integral with the wall of the diffuser duct and arranged to respond to a low pressure in the diffuser duct by choking the throat. 
     
     
         15 . The cyclone filtration assembly unit in accordance with  claim 14  wherein the regulator responds to low pressure in the diffuser duct by opening an aperture in the injector tube to allow fresh air into the diffuser duct. 
     
     
         16 . The cyclone filtration assembly unit in accordance with  claim 1  wherein the injector tube is in fluid communication at the housing aperture to a vacuum cleaner motor to provide forced clean air induction through the injector. 
     
     
         17 . The cyclone filtration assembly unit in accordance with  claim 1  wherein the injector unit is a De Laval nozzle arrangement such that the nozzle is a converging nozzle for delivering clean air to the diffuser, and there is then downstream from there, a diverging region for mixing and converting the kinetic energy of the flow to pressure. 
     
     
         18 . The cyclone filtration assembly unit in accordance with  claim 17  wherein the diverging region is adjacent the dirty air inlet, and the diffuser duct then converges again to provide more kinetic energy and further mixing, and then downstream from the diffuser duct, at its outlet, delivery of the mixed fluid to the cyclone separator element. 
     
     
         19 . The cyclone filtration assembly unit in accordance with  claim 1  wherein the injector inlet is angled at between 110 and 150 degrees to the diffuser duct to reduce pressure loss therein. 
     
     
         20 . The cyclone filtration assembly unit in accordance with  claim 1  wherein the injector tube has a cross-sectional area of between about 15% and 35% of the cross sectional area of the diffuser duct to provide greater suction and efficiencies of filtering. 
     
     
         21 . A vacuum cleaner including:
 a hose and nozzle inlet for drawing dirt from a surface;   a motor for drawing air through the hose and nozzle inlet;   a cyclone filtration assembly unit in accordance with  claims 1  to  20 .   
     
     
         22 . (canceled) 
     
     
         23 . (canceled)