Abstract:
Provided is a dishwasher. The dishwasher includes a sump case forming a space to store wash liquid, and a drain pump provided at one side of the sump case. The drain pump includes a drain impeller that induces a flow of wash liquid, and a plurality of mutually separable cases covering the drain impeller.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present disclosure relates to subject matter contained in priority Korean Application No. 10-2006-0093859, filed on Sep. 27, 2006, which is herein expressly incorporated by reference in their entirety. 
     BACKGROUND 
     The present disclosure relates to a dishwasher. 
     A dishwasher is a household appliance that removes impurities such as food residue from dish surfaces using wash liquid. 
     A dishwasher includes a tub that forms a wash chamber, a sump installed at the bottom of the tub to store wash liquid, a wash pump installed within the sump for pumping wash liquid, spray arms/nozzles provided within the tub for spraying wash liquid, withdrawable dish racks installed in the tub to store dishes, and a drain pump for draining dirty water from within the sump. 
     Wash liquid flowing to the spray arms/nozzles by the pumping action of the wash pump is sprayed at high pressure through spray holes formed in the spray arms/nozzles. The wash liquid sprayed at high pressure collides against surfaces of dishes stored within the tub, so that food residue and other impurities on the dishes fall to the floor of the tub. In this way, dishes stored within the dish racks are washed. Then, the wash liquid containing impurities that enters the sump is drained to the outside by the drain pump. 
     However, in a related art drain pump, the housing holding the drain impeller is formed integrally with the sump case, so that it is difficult to clean the inside of the drain pump. 
     When the inside of the drain pump is not properly cleaned, the drain pump can become clogged. 
     SUMMARY 
     Embodiments provide a dishwasher. A dishwasher according to embodiments includes a sump case forming a space to store wash liquid, and a drain pump provided at one side of the sump case. The drain pump includes a drain impeller that induces a flow of wash liquid, and a plurality of mutually separable cases covering the drain impeller. 
     The details of one or more embodiments are set forth in the accompanying drawings and the description below. Other features will be apparent from the description and drawings, and from the claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a sectional view of a dishwasher according to the present embodiments. 
         FIG. 2  is a perspective view of a dishwasher sump according to the present embodiments. 
         FIG. 3  is an exploded perspective view of a sump according to the present embodiments. 
         FIG. 4  is a perspective view showing a sump case and a drain pump cover according to the present embodiments. 
         FIG. 5  is a perspective view of a portion of a drain pump according to the present embodiments. 
         FIG. 6  is a perspective view of a drain pump cover according to the present embodiments. 
         FIG. 7  is a sectional view of  FIG. 6  cut along line I-I′. 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     Reference will now be made in detail to the embodiments of the present disclosure, examples of which are illustrated in the accompanying drawings. 
       FIG. 1  is a sectional view of a dishwasher according to the present embodiments. 
     Referring to  FIG. 1 , a dishwasher  10  according to the present embodiments includes a tub  11  forming a wash chamber  19 , a door  18  provided at the front of the tub  11  to open and close the wash chamber  19 , a sump  100  provided at the bottom of the tub  11  for storing wash liquid, and dish racks  12  and  13  provided within the tub for storing dishes. 
     The dishwasher  10  also includes a wash motor  230  installed at the bottom of the sump  100  to drive a wash pump (described below) that is installed within the sump  100 , a water guide  14  coupled at the top of the sump to function as a passage for the wash liquid pumped by the wash pump  230 , a lower spray arm  16  coupled at the top of the sump  100  to spray wash liquid in an upward direction, an upper spray arm  15  selectively coupled at the upper part of the water guide  14 , and a top nozzle  17  located near the ceiling of the tub  11  to spray wash liquid downward. 
     In detail, the dish racks  12  and  13  consist of an upper rack  12  and a lower rack  13 . The dish racks  12  and  13  slide forward and backward within the tub  11 . 
     The upper spray arm  15  is disposed below the upper rack  12 , and the lower spray arm  16  is disposed below the lower rack  13 . 
     Below, a description of the operation of the above dishwasher  10  will be given. 
     A user first pulls the door  18  to open the wash chamber  19 . Then the user pulls the upper rack  12  and/or the lower rack  13  outward from the wash chamber  19 . Next, dishes are placed in the upper rack  12  and/or lower rack  13 , after which the upper rack  12  and/or lower rack  13  is pushed back into the wash chamber  13  and the door  18  is closed to seal the wash chamber  19 . 
     Then, a power button is pressed to supply power to the dishwasher  10 . 
     When power is supplied to the dishwasher  10 , a wash course is begun. When the wash course is performed, wash liquid flows into the sump  100  through a water supply inlet. After a predetermined amount of wash liquid enters the sump  100 , the wash motor  230  operates. A motor shaft  231  connected to the wash motor  230  rotates, and an impeller  151  (in  FIG. 3 ) connected to the motor shaft  231  also rotates, prompting a flow of wash liquid to the upper spray arm  16  and the water guide  14 . The wash liquid that flows to the water guide  14  is sprayed through the top nozzle  17  and the upper spray arm  15  into the wash chamber  19 . The thus sprayed wash liquid washes surfaces of dishes stored in the upper rack  12  and/or the lower rack  13 . 
     In detail, the top nozzle  17  sprays wash liquid downward, the upper spray arm  15  sprays wash liquid upward, and the lower spray arm  16  sprays wash liquid upward. 
     Dirty water that collects in the sump  100  is filtered of impurities by a filter (not shown). The filtered wash liquid is discharged to the outside of the dishwasher  10  through a drain pump. 
     When wash liquid is discharged to the outside, fresh wash liquid enters the sump  100  once more through the water supply inlet, to be sprayed through the spray arms  15  and  16 , as in the wash cycle. The dishes are rinsed in a rinse cycle by the clean wash liquid that is sprayed. When the rinse cycle of the dishes is completed, a drying cycle is performed, completing the wash course of the dishwasher  10 . 
     Below, a detailed description of the sump  100  according to the present embodiments is provided. 
       FIG. 2  is a perspective view of a dishwasher sump according to the present embodiments, and  FIG. 3  is an exploded perspective view of a sump according to the present embodiments. 
     Referring to  FIGS. 2 and 3 , a sump  100  according to the present embodiments includes a sump case  200  forming a wash liquid reservoir  205 , a sump cover  130  covering the top of the sump case  200 , a lower spray arm holder  110  coupled at the top of the sump cover  130  and connected to the lower spray arm  16 , a wash motor  230  installed below the sump case  200  to drive the wash pump  150 , a drain pump  300  to discharge wash liquid containing impurities to the outside, and a drain motor  340  that drives the drain pump  300 . 
     The sump  100  also includes a heater  201  inserted through the side of the sump case  200  to be disposed in the wash liquid reservoir  205  for heating wash liquid, a disposer  180  coupled to the shaft  231  of the wash motor  230  for grinding food particles included in wash liquid, a wash pump  150  driven by the wash motor  230  to pump wash liquid stored in the wash liquid reservoir  205 , a passage guide  140  disposed between the sump cover  130  and the pump case  170  and in which a soil chamber  141  that collects impurities is formed, and a screen filter provided below the wash pump  150  to prevent food particles ground by the disposer  180  from entering the wash pump  150 . 
     Specifically, the wash pump  150  includes an impeller  151  coupled to the shaft  231  of the wash motor  230 , and a wash pump case  152  forming a housing  153  in which the impeller  151  is housed. The wash pump case  152  is coupled to the sump case  200 . 
     A passage control valve  220  is disposed at one end on the top surface of the wash pump case  152 , to direct wash liquid pumped by the wash pump  150  alternatingly to the lower spray arm passage  143  and the water guide passage  142  (described below). 
     Also, wash liquid stored in the wash liquid reservoir  205  passes through the portion in which the screen filter  171  is installed, and is suctioned into the wash pump  150 . The suctioned wash liquid flows along the passage formed in the wash pump case  152  to the passage control valve  220 . 
     The passage guide  140  is coupled to the top of the wash pump case  152 . A lower spray arm passage  143  and a water guide passage  142  are formed on the passage guide  140  to direct the wash liquid pumped by the wash pump  150  to the lower spray arm  16  and the water guide  14 . 
     Formed at the passage guide  140  are a soil chamber  141  that collects food residue, and a chamber discharge hole  144  that allows wash liquid to drain to a drain guide  322  formed on the drain pump  320  (to be described later). 
     Wash liquid flowing through a sampling passage  145  formed to communicate with a portion in which the passage control valve  220  is formed flows through a chamber discharge hole  144  and enters the drain guide  322 . Then the wash liquid flows through the drain guide  322  and the chamber discharge hole  144  into the soil chamber  141 . 
     Thus, impurities collect in the soil chamber  141 . Here, a self-cleaning filter  120  formed on the soil chamber  141  prevents the impurities from entering the tub  11 . 
     The sump cover  130  is mounted on the top surface of the guide passage  140 , and exposes the floor of the tub  11 . A plurality of holes is formed around the edge of the sump cover  130  to allow wash liquid within the tub  11  to enter the wash liquid reservoir  205 . 
     The self-cleaning filter  120 , formed in the approximate center of the sump cover  130 , includes an upper supporting plate  121 , a mesh filter  122 , and a lower supporting plate  123 . 
     In detail, the self-cleaning filter  120  is formed to cover the top of the soil chamber  141 , prevents impurities in the soil chamber  141  from leaking into the tub  11 , and allows only wash liquid to enter the tub  11 . Thus, impurities are prevented from entering the wash chamber  19  by means of the self-cleaning filter  120 . 
       FIG. 4  is a perspective view showing a sump case and a drain pump cover according to the present embodiments,  FIG. 5  is a perspective view of a portion of a drain pump according to the present embodiments,  FIG. 6  is a perspective view of a drain pump cover according to the present embodiments, and  FIG. 7  is a sectional view of  FIG. 6  cut along line I-I′. 
     Referring to  FIGS. 4 through 7 , the sump case  200  includes the wash liquid reservoir  205 , and the drain pump  300  provided at one side of the wash liquid reservoir  205 . 
     Specifically, a motor shaft through-hole  203  is formed at the center of the wash liquid reservoir  205  for the shaft  231  of the wash motor  230  to pass through. Also, a valve shaft through-hole  204  is formed in another region of the wash liquid reservoir  205  for a shaft operating the passage control valve  220  to pass through. 
     The valve pump  300  includes a drain impeller  330  for draining wash liquid, and a drain pump case  310  and pump cover  320  forming a housing to protect the drain impeller  330 . 
     In detail, the drain pump case  310  is integrally formed with the sump case  200 . The drain pump cover  320  is detachably coupled to the drain pump case  310 . 
     A cover mounting portion  316 , on which the drain pump cover  320  is mounted, is formed on the drain pump case  310 . The cover mounting portion  316  is formed in a stepped manner. The drain pump cover  320  mounted on the cover mounting portion  316  is also stepped to correspond to the cover mounting portion  316 . The drain pump case  310  and the drain pump cover  320  are engaged at the respective stepped portions of the drain pump case  310  and the drain pump cover  320 . 
     Thus, when it is necessary to clean the wash pump, a user is able to separate the wash pump cover  320  from the drain pump case  310 , and easily clean the inside of the drain pump  310 , thereby increasing user convenience. 
     Also, a drain hole  309  is formed in the sump case  200 , through which the drain impeller  330  passes and which allows wash liquid to drain. 
     The drain pump cover  320  includes an impeller covering portion  325  that encloses the portion above the drain impeller  330 , and a drain guiding portion  322  that induces the flow of wash liquid toward the drain impeller  330 . The impeller covering portion  325  is rounded. 
     The drain guiding portion  322  includes an opening  321  open at the top and bottom. When the drain pump cover  320  is mounted on the drain pump case  310 , the lower open portion of the drain guiding portion is covered by the drain pump case  310 . 
     A rib home  328  is formed in the upper edge of the drain guiding portion  322  to couple with a rib (not shown) formed on the chamber discharge hole  144 . 
     Also, a wash liquid inlet  323  that allows wash liquid in the wash liquid reservoir  205  to flow into the drain guiding portion  322  is formed on a side of the drain guiding portion  322 . A check valve  326  is also provided on the drain guiding portion  322  to allow wash liquid in the wash liquid reservoir  205  to selectively enter the drain guiding portion  322 . 
     That is, the check valve  326  allows wash liquid in the wash liquid reservoir  205  to flow to the drain guiding portion  322 , and prevents the wash liquid and impurities in the drain guiding portion  322  from flowing into the wash liquid reservoir  205 . In other words, only when the pressure in the wash liquid reservoir  205  is higher than the pressure in the drain guiding portion  322 , does the check valve  326  open the wash liquid inlet  323 . 
     A pair of coupling ribs  327  for coupling the check valve  326  is formed on the drain guiding portion  322 . 
     Below, the operation of the sump  100  will be described. 
     First, when a wash course is begun, wash liquid flows from a water supply inlet into the sump case  200 . Then, the wash motor  230  rotates the impeller  151 . 
     When the impeller  151  rotates, the wash liquid enters the pump case  170 , and the wash liquid that enters the pump case  170  flows to the valve  220 . 
     Next, the wash liquid that flows to the valve  220  flows through the lower spray arm passage  143  and the water guide passage  142  formed on the top surface of the passage guide  140 , and into the water guide  14  and the lower spray arm holder  110 . 
     The wash liquid that moves to the water guide  14  and the lower spray arm holder  110  is sprayed through the upper spray arm  15  and the top nozzle  17  or the lower spray arm  16  toward the upper rack  12  and the lower rack  13 . 
     The thus sprayed wash liquid induces food residue deposited on the surfaces of dishes stored in the upper rack  12  and the lower rack  13  to fall to the floor of the tub  11 . The wash liquid that falls to the tub floor passes through the plurality of holes formed in the periphery of the sump cover  130 , and flows and collects in the wash liquid reservoir  205 , to be pumped by the wash pump  150  and re-circulated. 
     When the draining process is performed, the drain pump  300  operates by means of the drain motor  310 , and the wash liquid stored within the sump case  200  is discharged to the outside of the sump  100 . Simultaneously, the impurities deposited in the soil chamber  141  pass through the chamber discharge hole  144  and the drain guiding portion  322  to the outside of the sump  100 . 
     Although embodiments have been described with reference to a number of illustrative embodiments thereof, it should be understood that numerous other modifications and embodiments can be devised by those skilled in the art that will fall within the spirit and scope of the principles of this disclosure. More particularly, various variations and modifications are possible in the component parts and/or arrangements of the subject combination arrangement within the scope of the disclosure, the drawings and the appended claims. In addition to variations and modifications in the component parts and/or arrangements, alternative uses will also be apparent to those skilled in the art.