Patent Publication Number: US-2006005318-A1

Title: Washer control method and washer using the same

Description:
This application claims the benefit of Korean Application No. 10-2004-0052838 filed on Jul. 8, 2004, which is hereby incorporated by reference.  
     BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      The present invention relates to a fully automatic washer, and more particularly, to an apparatus and method for controlling the supply of water to such a washer using a multi-step water supply technique and by selectively driving a heater.  
      2. Discussion of the Related Art  
      A fully automatic washer is an apparatus for washing laundry by executing a series of steps according to a predetermined program or wash course, which typically includes wash course cycles of water supply, washing, rinsing, and dewatering. Here, it should be noted that the water is generally supplied to a tub directly from a service pipe at a temperature too low to dissolve a detergent adequately for washing, and the low temperature water also diminishes washer performance. In cold weather conditions, the temperature of water from a service pipe may be very low.  
      As an alternative, the washer may be connected to a hot water tap connected to an external device such as a home water heater, which consumes a great deal of energy to heat large amounts of water indiscriminately and to transport the heated water to a specific site for use at a specific time. The operation of such a device is particularly inefficient when only small amounts of heated water are needed for short periods of time, but efficiency may be improved by providing a heater to a washer, as disclosed in Korean Patent Application Laid-open No. 10-2003-0055973 (filed by the present applicant). Such a washer, however, still consumes energy excessively since the heater is driven indiscriminately, from the initial supply of water, to heat the water to a temperature set according to a user-selected course.  
     SUMMARY OF THE INVENTION  
      Accordingly, the present invention is directed to a washer control method and washer using the same that substantially obviate 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 method for controlling a water supply in a washer having a tub connected to a cold water source, a hot water source, a water level detector, a water temperature sensor, and a heater, which reduces energy consumption by performing a multi-step water supply.  
      Another object of the present invention is to provide a method for controlling a water supply in a washer having a tub connected to a cold water source, a hot water source, a water level detector, a water temperature sensor, and a heater, which maintains washing effectiveness by achieving a sufficient water temperature for dissolving detergent.  
      Another object of the present invention is to provide a method for controlling a water supply in a washer having a tub connected to a cold water source, a hot water source, a water level detector, a water temperature sensor, and a heater, which enables a selective control of the heater for maintaining a predetermined water temperature using a minimum of heater current.  
      Another object of the present invention is to provide a washer suitable for performing any of the above methods.  
      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 method for controlling a water supply in a washer having a tub connected to a cold water source, a hot water source, a water level detector, a water temperature sensor, and a heater. The method comprises selecting a wash course to set a predetermined water temperature; detecting a laundry amount to set a predetermined water level; first supplying the tub with an amount of water from the cold water source and the hot water source to reach a predetermined intermediate temperature for dissolving detergent in the amount of water; second supplying, after the first supplying, the tub with water from the hot water source to reach the predetermined water level as measured by the water level detector; driving, after the second supplying, the heater to heat the water in the tub to the predetermined water temperature as measured by the water temperature sensor; and executing the selected wash course.  
      In another aspect of the present invention, there is provided a washer, comprising a tub connected to a cold water source, a hot water source, a water level detector, a water temperature sensor, and a heater; and a controller for outputting a set of control signals for first supplying the tub with an amount of water from the cold water source and the hot water source to reach a predetermined intermediate temperature for dissolving detergent in the amount of water, for second supplying, after the first supplying, the tub with water from the hot water source to reach a predetermined water level as measured by the water level detector, and for driving, after the second supplying, the heater to heat the water in the tub to a predetermined water temperature as measured by the water temperature sensor.  
      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 block diagram of a washer according to the present invention;  
       FIG. 2  is a diagram of a water supply process according to the present invention; and  
       FIG. 3  is a flowchart of a washer control method 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.  
      Referring to  FIG. 1 , a washer according to the present invention controls the supply of water to a tub  200  for accommodating laundry to be washed according to a selected wash course. The washer includes a key input  100  for inputting a user command to select a specific wash course and to initiate washer operation, a water level detector  201  for detecting a desired level of water in the tub  200 , and a water temperature sensor  202  for sensing a desired temperature of the water in the tub, which is separately connected to a cold water source (not shown) and a hot water source (not shown). The desired water level varies according the amount of laundry in the tub  200 , detected at the time of initiating washer operation, and the desired water temperature is set when selecting the wash course. A controller  300 , which receives the output values of the water level detector  201  and the water temperature sensor  202  and stores reference values in a memory  400 , executes each cycle of the selected wash course by controlling a heater  600  for heating the water in the tub  200  and a motor  700  coupled to the tub. A display  800  may be provided for displaying an operational state of the washer.  
      In the operation of the above-described washer, a wash course is selected and an operation command (e.g., start) is input via the key input  100 , causing the controller  300  to output a set of control signals enabling the execution of the selected wash course, including control signals for performing a laundry amount detection to set up a water level, for controlling a desired supply of water to the tub  200  according to the detected laundry amount, and for controlling the temperature of the supplied water according to the selected wash course. The desired supply of water to the tub  200  is achieved by a multi-step water supply technique using a first water supply step followed by a second water supply step. In the first water supply, an intermediate water temperature, namely, a temperature (e.g., 32° C.) sufficiently high to dissolve completely a predetermined amount of detergent in the water, is achieved in the tub  200  by supplying both cold and hot water to the tub to a level below that corresponding to an amount of laundry. In the second water supply, a high water temperature, namely, a temperature corresponding to that of the hot water source, which is typically a temperature approaching or near the predetermined water temperature set according to the selected wash course, is achieved in the tub  200  by turning off the cold water and supplying only hot water to the tub until reaching the predetermined level set according the detected laundry amount. After reaching the predetermined water level by supplying only hot water, the water in the tub  200  is near the predetermined water temperature, and the heater  600  is selectively driven, as necessary, until the water temperature of the water in the tub reaches and maintains the predetermined water temperature. In the above two-step water supply technique, a detergent concentration is dissolved in a small amount of water for the first water supply, achieved using both cold and hot water as needed, but only the supply of hot water continues for the second water supply. Hence, the time for driving the heater  600  can be shortened to thereby reduce its energy consumption accordingly.  
      Referring to  FIG. 2 , a tub is supplied with cold water and hot water simultaneously, during a first water supply A, to achieve an intermediate temperature in the tub at a reduced water level. Here, the first water supply may be controlled according to the temperature of the hot water source, room ambient readings, measured water supply rates, etc. Thereafter, only the hot water is supplied during a second water supply B, i.e., the cold water supply is turned off, and the heater  600  is selectively driven according to a predetermined or desired water temperature. Once the desired water temperature is reached, the corresponding cycle C, e.g., a wash cycle or a rinse cycle, is carried out without driving the heater  600 .  
      Referring to  FIG. 3 , illustrating a method for controlling a water supply in a washer according to the present invention, a wash course is selected (S 101 ) using the key input  100 , whereby water temperature values are set and stored based on a set of default values determined according to the selection, and the user inputs an operation command (S 102 ) to execute a first water supply (S 103 ) in which hot water and cold water are simultaneously supplied to a tub. As the hot and cold water supply proceeds, the controller  300  determines (S 104 ) whether the output value from the water temperature sensor  202  reaches a first predetermined water temperature value stored in the memory  400 . Once the water in the tub reaches the first predetermined temperature, a second water supply is executed (S 105 ) in which the cold water supply is discontinued such that only the hot water is supplied. As the hot water supply proceeds, the controller determines (S 106 ) whether the output value from the water level detector  201  reaches a predetermined water level value stored in the memory  400  according to the detected laundry amount. Once the water in the tub reaches the predetermined level, the controller  300  then determines (S 107 ) whether the output value from the water temperature sensor  202  reaches a second predetermined water temperature value, which is stored in the memory  400  according to the selected wash course, while driving the heater  600  (S 108 ). Thus, the heater  600  is driven only after supplying the water to the predetermined water level and only until the thus-supplied water reaches the second predetermined water temperature, whereupon the controller  300  stops driving the heater (S 109 ) by controlling the driver  500  and thus cutting off a supply of current to the heater. Then, the controller  300  operates the motor  700  to execute the wash cycle (S 110 ) according to the selected wash course. Here, the executed cycle may be a wash cycle or any one of a plurality of rinse cycles.  
      As described above, the user selects a wash course, a supply of water to a tub is performed to attain a predetermined water temperature set according to the selected wash course is carried out by the two-step water supply technique of the present invention, and a heater for heating the water in the tub is selectively driven according to the predetermined water temperature. By adopting the present invention, washing water is supplied to a tub using a multi-step water supply technique, applied according to the selected wash course executed by a fully automatic washer separately connected to each of a cold water source and a hot water source, to reduce energy consumption while maintaining washing effectiveness. The tub is initially supplied by a first water supply of a small amount of water at a temperature sufficient for dissolving detergent and is then supplied by a second water supply to a predetermined water level from the hot water source only, which can be supplied at a high temperature, i.e., near a predetermined water temperature set according to the selected wash course. In doing so, a heater can be selectively driven, as needed, to its reduce energy consumption accordingly, since the heater is needed only to heat the predetermined water level from the high temperature of the hot water source to the predetermined water temperature.  
      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.