System and method for solvent recovery and purification in a low water or washless wash

Abstract

Method and apparatus for recovering and purifying a solvent used in an article cleaning appliance are provided. The method allows passing solvent-based cleaning fluid from a wash basket through a coarse filter configured to remove relatively large particulates from the cleaning fluid. The method further allows passing cleaning fluid from the coarse filter through a particulate filter configured to remove relatively fine particulates from the cleaning fluid. An aqueous phase that may be present in the cleaning fluid is separated by decanting and coalescing through a separator/filter assembly. The cleaning fluid may then be passed through a regeneration cartridge for removing any water that may remain in the cleaning fluid, and for adsorbing organic contaminants that may be present in the cleaning fluid. Recovered solvent may be stored in a tank for subsequent use in a cleaning process performed by the appliance.

1 . An article cleaning apparatus comprising: 
 an air management mechanism;    a cleaning basket assembly;    a fluid regeneration device;    a working fluid device coupled to said fluid regeneration device, said cleaning basket assembly, and said air management mechanism, said working fluid device comprising a fluid filter/separator assembly for substantially removing an aqueous phase that may be present in a solvent-based cleaning fluid that passes therethrough;    a clean fluid device coupled to said cleaning basket assembly and said fluid regeneration device; and    a controller coupled to said air management mechanism, said cleaning basket assembly, said working fluid device, said regeneration device, and said clean fluid device; wherein said controller is configured to control a cleaning process.    
   
   
       2 . The apparatus of  claim 1  wherein said filter/separator assembly comprises a decanting stage and a filter stage.  
   
   
       3 . The apparatus of  claim 2  wherein the filter stage comprises a filter element coated with a hydrophobic material.  
   
   
       4 . The apparatus of  claim 3  wherein the filter element comprises an axially-pleated filter element to facilitate precipitation of water droplets that coalesce thereon.  
   
   
       5 . The apparatus of  claim 2  wherein the decanting stage comprises a turbine centrifuge configured to separate a higher density fluid from a lower density fluid, wherein the higher density fluid comprises the aqueous phase that may be present in the solvent-based cleaning fluid, and the lower density fluid comprises cyclic siloxane solvent.  
   
   
       6 . The apparatus of  claim 5  wherein the filter stage is configured to substantially block passage to any aqueous phase that passes from the decanting stage.  
   
   
       7 . The apparatus of  claim 1  wherein the cleaning fluid further comprises a cleaning agent selected from the group consisting of sanitizing agents, emulsifiers, surfactants, detergents, bleaches, softeners, and any combination thereof.  
   
   
       8 . The apparatus of  claim 2  wherein the filter stage comprises a filter element having a pore size ranging from about 2 to 30 microns.  
   
   
       9 . The apparatus of  claim 1  wherein the cleaning fluid passes through the filter-separator assembly at a flow rate ranging from about 400 ml/min to about 1300 ml/min.  
   
   
       10 - 29 . (canceled)