Washing machine for drainage and circulation of wash water and controlling method thereof

Abstract

A washing machine can include a washing part configured to wash, rinse, and/or spin-dry laundry after water is supplied to a washing tub of the washing machine; a drain part, including a drain pipe connected to the washing part and a drain hose connected to a drain hole, and a pump configured to rotate an impeller connected to a rotation shaft of the pump in a forward direction or a backward direction; and a controller configured to rotate the impeller in the backward direction and circulate wash water into the washing tub through the drain pipe during a washing operation, and rotate the impeller of the pump in the forward direction and discharge the wash water through the drain hose during a drain operation.

What is claimed is: 
     
         1 . A washing machine, comprising:
 a washing part configured to wash, rinse, and/or spin-dry laundry after water is supplied to a washing tub in the washing machine;   a drain part comprising a drain pipe coupled to the washing part and a drain hose coupled to a drain hole, and further comprising a pump configured to rotate an impeller coupled to a rotation shaft of the pump in a forward direction or in a backward direction; and   a controller coupled to the drain part and configured to control the impeller to rotate in the backward direction and circulate wash water into the washing tub through the drain pipe during a washing operation, and further configured to control the impeller to rotate in the forward direction and discharge the wash water through the drain hose during a drain operation.   
     
     
         2 . The washing machine of  claim 1 , wherein the impeller is attached to the rotation shaft at an angle other than 0, 90 or 180 degrees relative to the rotation shaft. 
     
     
         3 . The washing machine of  claim 2 , wherein the impeller further comprises a normal impeller connected with the rotation shaft of the pump in a normal direction relative to the plane in which the impeller rotates. 
     
     
         4 . The washing machine of  claim 3 , wherein the impeller and the normal impeller are connected with each other. 
     
     
         5 . The washing machine of  claim 1 , wherein the impeller comprises a plurality of blades, and each of the blades is attached to the rotation shaft at an angle other than parallel or normal to the rotation shaft. 
     
     
         6 . The washing machine of  claim 5 , wherein each of the blades comprises a normal impeller that is normal to the plane in which the impeller rotates. 
     
     
         7 . The washing machine of  claim 1 , wherein when the controller controls the impeller of the pump to rotate in the backward direction in the washing operation, and in response to a predetermined and/or initial washing time elapsing, the controller stops the rotation of the impeller of the drain pump in the backward direction. 
     
     
         8 . The washing machine of  claim 1 , wherein when the controller rotates the impeller of the pump in the backward direction for each predetermined circulation cycle of the washing operation, and when each predetermined circulation cycle ends, then the controller stops the rotation of the impeller of the drain pump in the backward direction. 
     
     
         9 . A method of controlling a washing machine, comprising:
 washing laundry using a washing part of the washing machine after water is supplied to a washing tub of the washing machine;   during the washing operation, under control of a controller, rotating in a backward direction an impeller connected with a rotation shaft of a pump and circulating wash water into a washing tub through a drain pipe;   rotating, under control of the controller, the impeller in a forward direction and discharging wash water through a drain hose; and   rinsing and spin-drying the laundry.   
     
     
         10 . The method of  claim 9 , wherein in the washing operation, when the impeller of the pump is rotating in the backward direction and a predetermined and/or initial washing time elapses, then the controller stops the rotation of the impeller in the backward direction. 
     
     
         11 . The method of  claim 9 , wherein in the washing operation, when the impeller of the pump is rotating in the backward direction for a predetermined circulation cycle of the washing operation and the circulation cycle ends, then the controller stops the rotation of the impeller in the backward direction. 
     
     
         12 . The method of  claim 9 , wherein the impeller is attached to the rotation shaft at an angle other than 0, 90 or 180 degrees relative to the rotation shaft. 
     
     
         13 . The method of  claim 12 , wherein the impeller further comprises a normal impeller connected with the rotation shaft of the pump in a normal direction relative to the plane in which the impeller rotates. 
     
     
         14 . The method of  claim 9 , wherein the impeller comprises a plurality of blades, and each of the blades is attached to the rotation shaft at an angle other than parallel or at a right angle relative to the rotation shaft. 
     
     
         15 . The method of  claim 14 , wherein each of the blades comprises a normal impeller that is normal to the plane in which the impeller rotates. 
     
     
         16 . A washing machine, comprising:
 a washing part configured to wash, rinse, and/or spin-dry laundry after water is supplied into a washing tub of the washing machine; and   a drain pump comprising an impeller coupled to a rotation shaft of the pump and configured to rotate in a forward direction and also configured to rotate in a backward direction, the drain pump coupled to a drain pipe coupled to (i) the washing part and (ii) a drain hose coupled to a drain hole;   wherein the impeller rotates in the backward direction and circulates wash water into the washing tub through the drain pipe during washing, and rotates in the forward direction and discharges the wash water through the drain hose after washing and rinsing and during spin-drying.   
     
     
         17 . The washing machine of  claim 16 , wherein the impeller is attached to the rotation shaft at an angle other than a right angle relative to the rotation shaft. 
     
     
         18 . The washing machine of  claim 17 , wherein the impeller further comprises a normal impeller connected with the rotation shaft of the pump in a normal direction relative to the plane in which the impeller rotates. 
     
     
         19 . The washing machine of  claim 16 , wherein when the impeller of the drain pump rotates in the backward direction during washing, and stops after a predetermined and/or initial time. 
     
     
         20 . The washing machine of  claim 16 , wherein the impeller of the drain pump rotates in the backward direction for a predetermined circulation cycle of the washing operation, and stops when the predetermined circulation cycle ends.