Abstract:
A washing machine is disclosed. An object of the present invention is to provide a washing machine having high efficiency which can reduce energy waste by controlling an operation of a circulation pump and a method for controlling the same. According to the washing machine of the present invention, unlike the prior art, the operation of circulation pump is controlled, considering the operation state of the motor, the heater or the water supply valve. Thus, energy waste may be prevented by the efficient control of the circulation pump.

Description:
[0001]     This application claims the benefit of the Patent Korean Application Nos. 10-2005-0077417 and 10-2005-0077418, filed on Aug. 23, 2005, which are hereby incorporated by reference as if fully set forth herein.  
       BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     The present invention relates to a washing machine, more particularly to a washing machine which operates a circulation pump more efficiently to reduce energy waste and a method for controlling the same.  
         [0004]     2. Discussion of the Related Art  
         [0005]     Generally, a washing machine is classified into a pulsator type washing machine and a drum type washing machine. The pulsator type washing machine has a tub rotating about a rotation shaft vertically mounted within a case and a pulsator (or an agitator). The drum type washing machine has a drum rotating about a rotation shaft horizontally mounted within a case.  
         [0006]      FIG. 1  is a sectional view illustrating a conventional drum type washing machine.  
         [0007]     As shown in  FIG. 1 , the conventional drum type washing machine includes a case  111 , a tub  112 , a drum  131  and an electric heater  135 . The case  111  has a cylindrical shape with an opened side and the tub  112  is mounted within the case  111  to hold wash water. The drum  131  is rotatably mounted within the tub  121  to rotate about a rotation shaft  132  mounted along a horizontal direction and the electric heater  135  is provided in a downside of the tub  121  to heat the wash water of the tub  121 .  
         [0008]     An opening  113  is formed in front of the case  111  and a door  115  is coupled to a circumference of the opening  113  to open/close the opening  113 . Also, a water supply valve  122  and a water supply pipe  123  are provided in an upper portion of the tub  121  to supply wash water into the tub. A water drain pipe  125  and a water drain pump  127  are provided in a lower portion of the tub. A motor  134  is mounted in rear of the tub  121  to rotatably operate the drum  131  through the rotation shaft  132 .  
         [0009]     Also, an electric heater  135  is provided in a lower portion between the drum  131  and the tub  121  to heat the wash water held within the tub  121 , and the electric heater  135  is spaced apart a predetermined distance from an inner surface of the tub  121  and along a front and rear direction. Although not illustrated in the drawings, a temperature sensor is provided in the tub  121  to sense the temperature of wash water.  
         [0010]     An end of the circulation channel  126  is in communication with an end of the water drain pipe  125  to circulate wash water within the tub  121 , and the other end of the circulation channel  126  is extended upwardly to communicate with an upper portion of the tub  121 . A circulation pump  128  is provided in the circulation channel  126  to circulate wash water.  
         [0011]     The conventional washing machine having the above configuration is operated without any relation with the motor, the heater or the water supply valve, when circulating wash water by using the circulation pump. Thereby, the conventional washing machine may have disutility in energy.  
         [0012]     More specifically, according to the conventional washing machine, the circulation pump is operated to circulate wash water right after wash water is heated by the electric heater. Since the temperature of wash water is high after being heated, the amount of heat emitted outside is large enough to cause a huge heat loss. Thereby, energy may be wasted. Also, since wash water is circulated right after being circulated, the heat loss generated during the circulation decreases the wash water temperature. Thereby, a washing function, especially, a sanitary function is not performed well.  
         [0013]     Furthermore, in the prior art, the circulation pump is operated in no connection with the motor rotating the drum. The circulation pump is turn on and maintains the state of being turned on continuously. Even in a state where the motor is off, the circulation pump is operated. Thereby, life of the pump deteriorates due to too much load on the circulation pump as well as electricity is wasted.  
         [0014]     Still further, in the prior art, even while wash water is supplied, the circulation pump is operated in a state of being turned on. Thereby, the amount of wash water cannot be measured precisely. Because of that, there is a problem of water waste. Since wash water is supplied much more than needed in washing, too much load is on the motor rotating the drum to shorten motor life as well as waste electricity. Also, in case that detergent is supplied together with wash water, wash water is circulated. Thus, bubble owing to the detergent might be generated a lot and the bubbles acts like resistance against the rotation of the drum. Thereby, there might be another cause of electricity waste.  
       SUMMARY OF THE INVENTION  
       [0015]     Accordingly, the present invention is directed to a washing machine.  
         [0016]     An object of the present invention is to provide a washing machine having high efficiency which can reduce energy waste by controlling an operation of a circulation pump and a method for controlling the same.  
         [0017]     Additional advantages, objects, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention. The objectives and other advantages of the invention may be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.  
         [0018]     To achieve these objects and other advantages and in accordance with the purpose of the invention, as embodied and broadly described herein, a washing machine includes a drum for holding the laundry; a motor for rotating the drum; a heater for heating wash water; a water supply valve for opening/closing a water supply channel of wash water; a circulation pump for circulating wash water; and a controller for controlling an operation of the circulation pump based on an operation state of at least one of the motor, the heater and the water supply valve.  
         [0019]     According to the washing machine of the present invention, unlike the prior art, the operation of circulation pump is controlled, considering the operation state of the motor, the heater or the water supply valve. Thus, energy waste may be prevented by the efficient control of the circulation pump.  
         [0020]     Here, the control of the circulation pump by the controller based on an operation state of the motor may be that the circulation pump is controlled to be on/off when the motor is on/off.  
         [0021]     Once the motor is operated to rotate the drum, the laundry within the drum is tumbled. At that time, if wash water is circulated, the washing efficiency is improved. Also, once the motor is not operated to stop the drum, the laundry is not tumbled and put on a bottom of the drum. At that time, commonly the circulation of wash water is not necessary.  
         [0022]     It is not economically efficient that the circulation pump is on to circulate wash water even without any particular reason in a state of the motor being off.  
         [0023]     Preferably, the control of the circulation pump operation is in communication with the motor operation state only in a predetermined period among washing courses.  
         [0024]     According to the present invention, the circulation pump is operated based on the operation of the motor rotating the drum. Thus, the circulation pump may be automatically controlled by only the control of the motor.  
         [0025]     Also, during the washing course where the drum is rotated by the motor, the circulation pump is operated to circulatively supply wash water to an upper portion of the drum. Thus, the washing effect which uses drop of wash water may be performed together with a washing effect generated by the drum operation, thereby resulting in improving the washing effect a lot.  
         [0026]     The control of the circulation pump by the controller based on the operation state of the water supply valve may be that the circulation pump is controlled to be off, if the water supply valve is opened.  
         [0027]     During the wash water supply, the circulation pump is off. Thereby, the amount of supplied wash water may be measured accurately. Because of that, the problem of water waste caused by supplying too much wash water may be solved. Also, since much load is not applied to the motor rotating the drum, motor life may be lengthened and electricity may not be wasted. Even when detergent is supplied together with wash water, bubbles which might be generated during the water supply in the prior art may be prevented. Thereby, the cause of electricity waste may be removed.  
         [0028]     Preferably, the control of the circulation pump by the controller based on the operation state of the heater is that the circulation pump is switched on a predetermined time after the heater is switched off.  
         [0029]     It may cause much heat loss that wash water is heated by the heater and circulated, and also it may not get an efficient sanitary effect.  
         [0030]     Preferably, the controller controls the circulation pump to be switched on a predetermined time after the temperature of wash water reaches a predetermined temperature, even in a state where the heater is not off.  
         [0031]     More preferably, the controller controls the circulation pump to be off, if the heater is on.  
         [0032]     Even when the circulation pump is on/off based on the motor operation state, the circulation pump may be controlled to be off while the water supply valve is opened.  
         [0033]     In another aspect of the present invention, a method for controlling a washing machine includes an operation state determination step for determining whether at least one of the motor for rotating a drum holding the laundry, a heater for heating wash water and a water supply valve for opening/closing a water supply channel of wash water is on; and a circulation pump control step for controlling an operation of a circulation pump based on the result of the operation state determination step.  
         [0034]     It is to be understood that both the foregoing general description and the following detailed description of the present invention are exemplary and explanatory and are intended to provide further explanation of the invention as claimed. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0035]     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:  
         [0036]      FIG. 1  illustrates a sectional view of a conventional drum type washing machine according to the prior art.  
         [0037]      FIGS. 2 and 3  illustrate a first embodiment of a washing machine according to the present invention.  
         [0038]      FIG. 4  illustrates a second embodiment of the washing machine according to the present invention.  
         [0039]      FIG. 5  illustrates a third embodiment of the washing machine according to the present invention.  
         [0040]      FIG. 6  illustrates a fourth embodiment of the washing machine according to the present invention. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0041]     Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.  
         [0042]     First of all, preferred embodiments of the present invention will be described as presenting a drum type washing machine as an example.  
         [0043]     A first embodiment of a drum type washing machine according to the present invention is almost the same as the conventional drum type washing machine in a technical configuration except a controller for controlling a motor, a circulation pump, a water supply valve and a heater.  
         [0044]     Also, a first embodiment of a method for controlling the washing machine according to the present invention may be a method for controlling a drum type washing machine according to the present invention.  
         [0045]     Thus, embodiments of the present invention will be described, referring to the sectional view of  FIG. 1  and flow charts of FIGS.  2  to  6 .  
         [0046]     As shown in  FIG. 2  of the first embodiment, a controller controls a circulation pump  128 . If a motor  134  for rotating a drum  131  is switched on, the circulation pump  128  is switched on. If the motor  134  is switched off, the circulation pump  128  is switched off.  
         [0047]     The controller checks whether a water supply for supplying wash water within the drum  131  is completed. After the water supply is completed, the controller controls the circulation pump  128  to be switched on/off, when the motor  134  is on/off.  
         [0048]     It is preferred that the circulation pump  128  is controlled to be off during the water supply, regardless of the motor operation state (an on/off state). Alternatively, the circulation pump  128  may be controlled to be on during the water supply, regardless of the motor operation state.  
         [0049]     Once the water supply into the drum  131  is completed and the circulation pump  128  is operated, the laundry may be dampened uniformly and quickly. the drum  131 , it is preferred that the circulation pump  128  is controlled to be off.  
         [0050]     Referring to a block view of  FIG. 2  illustrating the first embodiment of the present invention, the controller of the circulation pump  128  determines whether wash water supply is completed (S 1 ). If the water supply is completed, the controller determines whether the motor  134  is switched on (S 2 ). If the motor  134  is switched on, the circulation pump  128  is switched on (S 3 ). If the motor  134  is switched off, the circulation pump  128  is switched off (S 4 ).  
         [0051]     Referring to a block view of  FIG. 3 , the controller of the circulation pump  128  determines whether the motor  134  is switched on (S 11 ). If the motor  134  is switched off, the circulation pump  128  is switched off (S 14 ). Hence, the controller determines whether wash water is re-supplied into the drum  131  in a state of the motor  134  being on (S 12 ). If it is not the water re-supply, the circulation pump  128  is switched on (S 13 ). If it is the water re-supply, the circulation pump  128  is switched off (S 14 ).  
         [0052]      FIG. 4  is a block view illustrating the second embodiment where the circulation pump  128  is controlled based on a water supply valve operation state. As shown in  FIG. 4 , it is determined whether the water supply valve  122  is opened (S 21 ). If the water supply valve  122  is opened, the circulation pump  128  is controlled to be off (S 23 ). If the water supply valve  122  is closed, the circulation pump  128  is on (S 22 ). That is, wash water is not circulated during the wash water supply, considering the water supply valve operation state.  
         [0053]      FIG. 5  is a block view illustrating the third embodiment where the circulation pump  128  is controlled based on a heater operation state. As shown in  FIG. 5 , the controller checks whether the heater  135  is switched on (S 131 ). If the heater  135  is switched on, the circulation pump  128  is off (S 32 ). Hence, it is checked whether the heater  135  is off in a state of the circulation pump  128  being off (S 33 ). If the heater  135  is off, it is checked whether a predetermined time passes after the heater  135  is off (S 34 ). If the predetermined time passes, the circulation pump  128  is on (S 35 ).  
         [0054]     Although the heater  135  is not off after the circulation pump  128  is off, it is checked by a temperature sensor (not shown) whether the temperature of wash water reaches a predetermined temperature (S 36 ). If the temperature of wash water reaches the predetermined temperature, the circulation pump  128  is on in the predetermined time (S 34  and S 35 ).  
         [0055]     If the circulation pump  128  is controlled by the above method, wash water is not circulated for a predetermined time after the heater  135  heats wash water, such that there may be a sanitary effect. Thus, washing performance may be enhanced by the sanitary effect as well as less heat loss.  
         [0056]      FIG. 6  is a block view illustrating the fourth embodiment of the present invention.  
         [0057]     First, the controller determines whether circulation of wash water is needed (S 41 ). Here, the determination whether the circulation of wash water is needed may be the determination whether a circulation of wash water predetermined in relation with washing is started or not. For example, in case that detergent/water supply is completed and a wash water circulation course is predetermined during the main washing cycle, it is determined whether the wash water circulation starts.  
         [0058]     If the circulation of wash water is needed, the controller determines whether the motor  134  is on (S 42 ).  
         [0059]     If the motor  134  is off, the circulation pump  128  is controlled to be off (S 43 ).  
         [0060]     If the motor  134  is on, it is checked whether the water supply valve  122  is operated or the heater  135  is operated (S 44  and S 45 ).  
         [0061]     Water supply is performed while the water supply valve  122  is opened. Thus, the circulation pump  128  is controlled to be off (S 43 ). Water supply is not performed while the water supply valve  122  is closed. Thus, the circulation pump  128  is controlled to be on (S 47 ).  
         [0062]     While the heater  135  is on, wash water is heated. Thus, the circulation pump  128  is controlled to be off (S 43 ). While the heater  135  is off, it is determined whether a predetermined time passes in a state of the heater being off (S 46 ). Here, it is preferred that the predetermined time is 3˜5 minutes. During the predetermined time, wash water is not circulated, such that huge heat loss may not be caused. The laundry is soaked in relatively hot wash water, such that washing effect may be improved.  
         [0063]     If the predetermined time passes after the heater  135  is off, the circulation pump  128  is controlled to be on and wash water is circulated (S 47 ).  
         [0064]     The controller according to this embodiment controls the circulation pump to be on/off when the motor  134  is on/off. However, the circulation pump  128  is controlled, considering the operation state of the heater  135  or water supply valve  122 . Hence, if the predetermined circulation of wash water is completed, the controller finishes the circulation of wash water (S 48 ).  
         [0065]     The embodiment illustrated in  FIG. 6  is an appropriate combination of the embodiments illustrated in FIGS.  2  to  5  and any other various embodiments may be presented.  
         [0066]     Also, how the embodiments illustrated in FIGS.  2  to  5  are combined can vary the embodiments.  
         [0067]     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 inventions. Thus, it is intended that the present invention covers the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.