Progressive fine filtration for a dishwashing appliance

Abstract

A filtering system is provided for a dishwashing appliance that can remove fine particles from the wash and rinse fluids. The system uses a filter that can be rotated between filter media that are equipped for removal of different particulate sizes depending upon e.g., the cycle or stage of the cleaning process and/or anticipated particle size. The filter cartridge is positioned upstream from the pump inlet. In certain embodiments, the filter cartridge can be removable for servicing. In certain embodiments, all fluid received from the wash chamber can be passed through the fine filter so as to improve the removal of smaller particles from the wash or rinse fluids.

What is claimed is: 
     
         1 . A dishwashing appliance, comprising:
 a wash chamber having a sump portion;   a receptacle located in the sump portion, the receptacle defining an interior surface and a fluid outlet;   a pump in fluid communication with the sump portion of the wash chamber to receive fluid from the wash chamber;   a first filter positioned in the sump portion and configured for the receipt of fluid circulated through the wash chamber;   a rotatable, second filter positioned within the receptacle and configured for the receipt of fluid circulated through the wash chamber, the second filter defining a radial direction, axial direction, and circumferential direction, the second filter rotatable along the circumferential direction within the receptacle, the second filter comprising
 a cylindrically-shaped wall forming an internal chamber and comprising a first filter media positioned along the cylindrically-shaped wall; 
 a first axial seal and a second axial seal, each extending along the axial direction and each extending radially from the cylindrically-shaped wall of the second filter towards the interior wall of the receptacle; and 
 at least one circumferential seal extending circumferentially between the first axial seal and the second axial seal; and 
   wherein the second filter is rotatable between i) a first position in which fluid from the wash chamber filters simultaneously through both the first filter and the second filter to flow to the pump and ii) a second position in which the seals surround the fluid outlet of the receptacle so that fluid from the wash chamber filters only through the second filter to flow to the pump.   
     
     
         2 . The dishwashing appliance of  claim 1 , wherein the interior wall of the receptacle is circular in shape. 
     
     
         3 . The dishwashing appliance of  claim 1 , wherein in the first position the seals do not surround the fluid outlet of the receptacle. 
     
     
         4 . The dishwashing appliance of  claim 1 , wherein the first filter comprises a grate covering a recess defined in the sump portion of the wash chamber. 
     
     
         5 . The dishwashing appliance of  claim 4 , wherein the second filter defines a fluid inlet for the flow of fluid into the internal chamber of the second filter, and wherein the fluid inlet for the second filter is at least partially surrounded by the grate. 
     
     
         6 . The dishwashing appliance of  claim 1 , wherein the interior wall of the receptacle and the second filter form a gap that receives filtered fluid from the first filter. 
     
     
         7 . The dishwashing appliance of  claim 1 , further comprising at least one controller configured to
 locate the second filter in the first position during a wash cycle; and   locate the second filter in the second position during a rinse cycle.   
     
     
         8 . The dishwashing appliance of  claim 1 , wherein the second filter comprises a cartridge that is removable from the receptacle. 
     
     
         9 . The dishwashing appliance of  claim 1 , wherein the first filter is configured with filter openings in the range of about 0.030 inches to about 0.060 inches. 
     
     
         10 . The dishwashing appliance of  claim 9 , wherein the second filter is configured with filter openings in the range of about 50 microns to about 150 microns. 
     
     
         11 . A dishwashing appliance, comprising:
 a wash chamber having a sump portion;   a receptacle located in the sump portion, the receptacle defining an interior wall and a fluid outlet;   a pump in fluid communication with the sump portion of the wash chamber to receive fluid from the wash chamber;   a rotatable filter positioned within the receptacle and configured for the receipt of fluid circulated through the wash chamber, the filter defining a radial direction, axial direction, and circumferential direction, the filter rotatable along the circumferential direction within the receptacle, the filter comprising
 a cylindrically-shaped wall forming an internal chamber and comprising a first filter media, a second filter media, and a third filter media, all positioned along the cylindrically-shaped wall and adjacent to each other along the circumferential direction; 
 a first axial seal, a second axial seal, and a third axial seal, each extending along the axial direction and each extending radially from the cylindrically-shaped wall of the filter towards the interior wall of the receptacle; 
 a first circumferential seal extending circumferentially between the first axial seal and the second axial seal; 
 a second circumferential seal extending circumferentially between the second axial seal and the third axial seal; and 
 a third circumferential seal extending circumferentially between the third axial seal and the first axial seal; 
   wherein the filter is rotatable between i) a first position in which the fluid from the wash chamber filters only through the first filter media to flow to the pump, ii) a second position in which fluid from the wash chamber filters only through the second filter media to flow to the pump; and iii) a third position in which fluid from the wash chamber filters only through the third filter media to flow to the pump.   
     
     
         12 . The dishwashing appliance of  claim 11 , wherein the interior wall of the receptacle is circular in shape. 
     
     
         13 . The dishwashing appliance of  claim 11 , wherein in the first position the fluid outlet of the receptacle is surrounded by the first axial seal, the second axial seal, and the first circumferential seal. 
     
     
         14 . The dishwashing appliance of  claim 13 , wherein in the second position the fluid outlet of the receptacle is surrounded by the second axial seal, the third axial seal, and the second circumferential seal. 
     
     
         15 . The dishwashing appliance of  claim 14 , wherein in the third position the fluid outlet of the receptacle is surrounded by the third axial seal, the first axial seal, and the third circumferential seal. 
     
     
         16 . The dishwashing appliance of  claim 11 , wherein the first filter media is configured with filter openings in the range of about 0.030 inches to about 0.060 inches. 
     
     
         17 . The dishwashing appliance of  claim 16 , wherein the second filter media is configured with filter openings in the range of about 300 microns to about 600 microns. 
     
     
         18 . The dishwashing appliance of  claim 17 , wherein the third filter media is configured with filter openings in the range of about 50 microns to about 150 microns. 
     
     
         19 . A dishwashing appliance, comprising:
 a wash chamber having a sump portion;   a receptacle located in the sump portion, the receptacle defining an interior wall and a fluid outlet;   a pump in fluid communication with the sump portion of the wash chamber to receive fluid from the wash chamber;   a first filter positioned in the sump portion and configured for the receipt of fluid circulated through the wash chamber;   a rotatable, second filter positioned within the receptacle and configured for the receipt of fluid circulated through the wash chamber, the second filter defining a radial direction, axial direction, and circumferential direction, the second filter rotatable along the circumferential direction within the receptacle, the second filter comprising
 a cylindrically-shaped wall forming an internal chamber and comprising a first filter media, a second filter media, and a third filter media positioned along the cylindrically-shaped wall; 
 a first axial seal and a second axial seal, each extending along the axial direction and each extending radially from the cylindrically-shaped wall of the second filter towards the interior wall of the receptacle; and 
 at least one circumferential seal extending circumferentially between the first axial seal and the second axial seal; and 
   wherein the second filter is rotatable between i) a first position in which fluid from the wash chamber filters simultaneously through both the first filter and the first filter media to flow to the pump; ii) a second position in which fluid from the wash chamber filters simultaneously through both the first filter and the second filter media to flow to the pump; and iii) a third position in which fluid from the wash chamber flows only through the third filter media to flow to the pump.   
     
     
         20 . The dishwashing appliance of  claim 19 , wherein in the third position the fluid outlet of the receptacle is surrounded by the first axial seal, the second axial seal, and the circumferential seal.