Abstract:
A filter assembly for a dishwasher is provided. The filter assembly includes a water circulator for supplying washing and rinsing water under pressure to the filter assembly, and at least one cleaning nozzle positioned at a predetermined position adjacent an outer circumference of the filter assembly. The at least one cleaning nozzle is provided in communication with the water circulator, and prevents excessive accumulation of waste particles in the filter assembly by periodically spraying pressurized water into the filter assembly.

Description:
This application claims the benefit of Korean Application No. 10-2002-0074989 filed on Nov. 29, 2002, which is hereby incorporated by reference. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a dishwasher, and more particularly, to a filter assembly employing a cleaning nozzle to clean the filters of a dishwasher. 
     2. Discussion of the Related Art 
     Referring to  FIG. 1 , a general dishwasher is comprised of a washtub  4 , installed in a body  2  forming an exterior, for holding tableware and the like on a sliding rack  12 ; a sump  6 , installed under the washtub, for collecting runoff water; a plurality of injection nozzles  14  for spraying water toward the rack from an injection passage  14   a  connected to the sump; a wash pump assembly  8 , installed at one side of the sump, for circulating water using a wash pump  8   b  connected to a pump body  8   a;  a drain pump assembly  10 , installed at the other side of the sump, for draining the water; and a filter assembly  20 , installed in a filter holder  6   a  provided at a center of the sump, for filtering waste particles from the water before draining or re-circulating. 
     The filter assembly  20  includes a series of concentrically first, second, and third filters  22 ,  24 , and  26 , each of which is provided with a progressively larger receptacle for fitting one into the other. Accordingly, as the circulating water passes through the filters  22 ,  24 , and  26 , large waste particles are filtered prior to smaller particles. After using the dishwasher, a user manually removes from the filters  22 ,  24 , and  26  the waste filtered by the filter assembly  20 . 
     In the above dishwasher using a filter assembly according to the related art, however, minute particles of waste tend to accumulate on the outer filter  26 , to block the filters and impede water circulation accordingly. A reduction of water circulation degrades washing performance, and a complete blockage will preclude operation and force the user to clean the filters manually. 
     SUMMARY OF THE INVENTION 
     Accordingly, the present invention is directed to a filter assembly of a dishwasher that substantially obviates one or more of the problems due to limitations and disadvantages of the related art. 
     An object of the present invention, which has been devised to solve the foregoing problem, lies in providing a filter assembly of a dishwasher, by which the undue accumulation of waste particles filtered from circulating water is prevented by periodically spraying water directly into the filter assembly. 
     It is another object of the present invention to provide a filter assembly of a dishwasher, which facilitates water circulation to improve wash performance. 
     It is another object of the present invention to provide a filter assembly of a dishwasher, which reduces the need for the filters of the filter assembly to be cleaned manually. 
     Additional features and advantages of the invention will be set forth in the description which follows, and in part will be apparent to those having ordinary skill in the art upon examination of the following or may be learned from a practice of the invention. The objectives and other advantages of the invention will be realized and attained by the subject matter particularly pointed out in the specification and claims hereof as well as in the appended drawings. 
     To achieve these objects and other advantages in accordance with the present invention, as embodied and broadly described herein, there is provided a filter assembly for filtering waste particles in a dishwasher. The filter assembly comprises water circulating means for supplying washing and rinsing water under pressure to the filter assembly; and at least one cleaning nozzle, provided at a predetermined position along an outer circumference of the filter assembly, to communicate with the water circulating means, wherein the pressurized water of the water circulating means is sprayed into the filter assembly. 
     It is to be understood that both the foregoing explanation and the following detailed description of the present invention are exemplary and illustrative and are intended to provide further explanation of the invention as claimed. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the principle of the invention. In the drawings: 
         FIG. 1  is a cross-sectional view of a general dishwasher; 
         FIG. 2  is a cross-sectional view of a dishwasher adopting a filter assembly according to the present invention; and 
         FIG. 3  is a perspective breakaway view of an apparatus for cleaning filters in a dishwasher according to the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Reference will now be made in detail to the preferred embodiment of the present invention, examples of which are illustrated in the accompanying drawings. Throughout the drawings, like elements are indicated using the same or similar reference designations where possible. 
     The present invention is directed towards the filter assembly for filtering waste particles in a dishwasher. The filter assembly is comprised of series of concentrically arranged filters having varyingly sized filter holes, respectively, wherein the outer filter of the filter assembly has the smallest holes. 
     Referring to  FIGS. 2 and 3 , a dishwasher adopting a filter assembly according to the present invention is comprised of a washtub  54 , installed in a body  52  forming an exterior, for holding tableware and the like on a sliding rack  62 ; a sump  56 , installed under the washtub, for collecting runoff water; a plurality of injection nozzles  64  for spraying water toward the rack from an injection passage  64   a  connected to the sump; a wash pump assembly  58 , installed at one side of the sump, for circulating water using a wash pump  58   b  connected to a pump body  58   a;  a drain pump assembly  60 , installed at the other side of the sump, for draining the water; and a filter assembly  70 , installed in a filter holder  56   a  provided at a center of the sump, for filtering waste particles from the water before draining or re-circulating. 
     The filter assembly  70  includes a series of concentrically arranged first, second, and third filters  72 ,  74 , and  76 , each of which is provided with a progressively larger receptacle for fitting one into the other. The first, second, and third filters  72 ,  74 , and  76  are provided with a multitude of progressively smaller filter holes  72   a,    74   a,  and  76   a,  respectively, to filter larger particles prior to smaller particles. The third filter  76  is fixed to the filter holder  56   a  of the sump  56 , the second filter  74  is detachably installed in the third filter  76 , and the first filter  72  is detachably installed in the second filter  74 . Accordingly, large, medium-sized, and small waste particles are filtered by the first to third filters  72 ,  74 , and  76 , respectively, with the third filter filtering the most minute particles. 
     In addition, a cleaning nozzle  80  is installed adjacent the outer circumference of the third filter  76  of the filter assembly  70 . The cleaning nozzle  80 , which is thus juxtaposed to the third filter  76  having the smallest holes, comprises a cylindrical nozzle body  82  installed in the filter holder  56   a  of the sump  56 , to communicate with a water supply valve assembly (not shown) and the wash pump assembly  58 ; and a multitude of injection holes  84  perforating in the nozzle body, so as to face the filter assembly  70 . Accordingly, using the water from a water circulating means comprised of the sump  56 , the water supply valve assembly, and the wash pump assembly  58 , water is periodically upon the supply of water to the water circulating means sprayed through the injection holes  84  of the cleaning nozzle  80  directly into the filter assembly  70 . Hydraulic pressure, provided by the water pump of the water circulating means, is used to clean the filter assembly whenever water is supplied for washing or rinsing. Thus, there is no need for a separate pressurizing device. According to the present invention, a plurality of cleaning nozzles  80 , each having a number of injection holes  84  formed at intervals in a nozzle body  82 , are preferably formed at predetermined positions along the outer circumference of the filter assembly  70 . The size of the resulting number of injection holes  84  formed in the nozzle body  82  is determined by the pressure of water supplied by a service pipe supplying pressurized water to the water circulating means. 
     In the operation of the dishwasher according to the present invention, with water supplied, the wash pump  58   b  is actuated to perform the washing of tableware placed in the rack  62 , whereupon the water in the sump  56  is sprayed toward the rack via the injection passage  64   a  and the nozzles  64 . The water thus circulates through the sump  56 , injection passage  64   a,  nozzles  64 , and washtub  54 . Waste particles from the tableware are filtered from the circulating water in the filter assembly  70  installed in the sump  56 , with filtering progressing as water circulates via the water circulating means. A similar process is executed for rinsing. 
     That is, during washing and rinsing, as water is supplied to the sump via the water supply valve, the water is sprayed via the cleaning nozzle  80  directly into the third (outer) filter  76 , and indirectly into the second and first (inner) filters  74  and  72 , whereby waste particles are filtered from the circulating water and the most minute particles of the third filter are cleaned periodically. Hence, the blocking of water circulation due to the accumulation of particles on the third filter  76  is prevented, to reduce the need for the filter to be cleaned manually. The spraying action of the cleaning nozzle  80  also reduces blockage in the filter holes  72   a  and  74   a  of the inner filters. Thus, water circulation is facilitated and wash performance is improved accordingly. 
     It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention. Thus, it is intended that the present invention cover such modifications and variations, provided they come within the scope of the appended claims and their equivalents.