Removable dishwasher filtration system

Abstract

A dishwasher having a removable filtration system includes a main coarse filter screen having a central opening for removably fitting the filter screen around a water distribution manifold. The filter screen includes an outer circumferential rim portion have an elastomeric seal over-molded thereto which is press-fit into a channel in a lower sump unit such that the filter screen is suspended over a sump enclosure. A finer, secondary strainer extends through the filter screen and provides secondary filtering of washing fluid entering the sump enclosure through the filter screen. Preferably, the filtration system also includes a non-removable or backup strainer which provides coarse straining of washing fluid should a user fail to properly reinstall the removable filter screen and/or the secondary strainer.

1 . A dishwasher having a removable dishwasher filtration system comprising:
 a tub defining a washing chamber;   a water distribution manifold in communication with at least one spray arm;   a sump unit within the washing chamber including a support surface having a bottom wall and a side wall defining a channel;   a filter screen having a main body portion including an aperture therein and an outer rim portion having an integrated elastomeric seal positioned in the channel in sealed engagement with the support surface such that the filter screen is held suspended by the engagement of the outer rim portion with the support surface, wherein the filter screen is adapted to filter debris from wash liquid entering the sump unit from the tub; and   a secondary strainer extending into the aperture in the screen and being readily removable therefrom for cleaning purposes, the secondary strainer being adapted to remove debris from wash liquid passing the filter screen and flowing through the sump unit.   
     
     
         2 . The dishwasher according to  claim 1 , wherein the filter screen is substantially circular and includes first and second arm portions which define a central opening through which the water distribution manifold extends. 
     
     
         3 . The dishwasher according to  claim 2 , wherein the first and second arm portions form a slot which leads to the central opening. 
     
     
         4 . The dishwasher according to  claim 1 , wherein the elastomeric seal is constituted by an over-molded rubber seal. 
     
     
         5 . The dishwasher according to  claim 4 , wherein the outer rim portion of the filter screen includes a downwardly turned flange about which the elastomeric seal is over-molded. 
     
     
         6 . The dishwasher according to  claim 5 , wherein the downwardly turned flange curves radially inwardly. 
     
     
         7 . The dishwasher according to  claim 5 , wherein the downwardly turned flange and the elastomeric seal are flexible, with the outer rim portion being press-fit into the channel, thereby preventing debris from bypassing the filter screen. 
     
     
         8 . The dishwasher according to  claim 1 , wherein the elastomeric seal includes a top wall portion which is substantially flush with a top wall portion of the sump unit when the outer rim portion is mounted in the channel. 
     
     
         9 . The dishwasher according to  claim 8 , wherein the elastomeric seal further includes a bottom wall portion and both inner and outer side wall portions. 
     
     
         10 . The dishwasher according to  claim 9 , wherein the channel is further defined by another side wall which is spaced radially from the side wall, said elastomeric seal being slightly compressed between the side wall and the another side wall within the channel to retain the filter screen in place. 
     
     
         11 . The dishwasher according to  claim 1 , wherein the filter screen is flexible. 
     
     
         12 . The dishwasher according to  claim 11 , wherein the filter screen is readily removable from the sump unit for cleaning purposes. 
     
     
         13 . The dishwasher according to  claim 1 , wherein the sump unit comprises a recessed main intake including an outlet, said secondary strainer extending into the main intake. 
     
     
         14 . The dishwasher according to  claim 13 , further comprising: a non-removable strainer mounted directly adjacent the outlet of the main intake, wherein the non-removable strainer is adapted to prevent coarse debris from entering the outlet. 
     
     
         15 . The dishwasher according to  claim 1 , wherein the filter screen comprises a dam portion which channels fluid toward the secondary strainer. 
     
     
         16 . A method of assembling a filtration system in a dishwasher having a tub defining a washing chamber and a sump unit below the washing chamber comprising:
 mounting a filter screen within the washing chamber by positioning an elastomeric seal provided on an outer rim portion of the filter screen in sealing engagement with support surfaces which define a channel of the sump unit; and   fitting a removable secondary strainer into an aperture provided in the filter screen, with the removable secondary strainer extending into a recessed main intake portion of the sump unit to remove debris from wash liquid passing the filter screen and flowing through the sump unit.   
     
     
         17 . The method of  claim 16 , wherein mounting the filter screen constitutes press-fitting a flexible outer rim portion of the filter screen, about which the elastomeric seal is over-molded, into the channel. 
     
     
         18 . The method of  claim 17 , wherein the elastomeric seal is compressed within the channel. 
     
     
         19 . The method of  claim 16  wherein, upon mounting the filter screen, a water distribution manifold extends into a central aperture formed in the filter screen. 
     
     
         20 . The method of  claim 16 , further comprising: fitting a non-removable strainer directly adjacent an outlet of the main intake portion to prevent coarse debris from entering the outlet.