Abstract:
A control system of a dishwasher in combination with an electrolyzed water production apparatus installed independently from the dishwasher, wherein electrolyzed alkaline water stored in a washing tank from the electrolyzed water production apparatus is used as washing water at a washing process and fresh water stored in a rinse tank from a source of water is used as rinse water at a rinse process, after the washing process; comprising the steps of activating the dishwasher to start operation at the rinse process so that the rinse water from the rinse tank is supplied into and stored in the washing tank; introducing the electrolyzed strong alkaline water into the washing tank in response to start of operation at the rinse process so that the alkaline water is diluted with the rinse water in the washing tank; and stopping the introduction of the electrolyzed alkaline water into the washing tank after lapse of a predetermined time.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to a dishwasher of the type using electrolyzed alkaline water. 
         [0003]    2. Discussion of the Prior Art 
         [0004]    As one of conventional dishwashers, there has been provided a dishwasher of the type in which washing water in a washing tank is used at a washing process and rinse water in a rinse tank or booster tank is used at a rinse process. This type of dishwasher is used widely in general, wherein an amount of water containing a detergent dissolved therein is used as washing water. 
         [0005]    In use of the dishwasher of the type described above, it is required from a point of view for protection of environment to reduce the amount of detergent used for washing, desirably to refrain use of the detergent. Under such requirements, high washing resolution of electrolyzed alkaline water produced in an electrolytic cell of the type with a partition membrane is noticed to use the electrolyzed alkaline water for substitution of the detergent. Proposed in the following patent documents are dishwashers capable of using the electrolyzed alkaline water for substitution of the detergent. 
         [0006]    The dishwashers proposed in the patent documents each are provided integrally with an electrolytic cell designed only for use therein. For example, the dishwasher proposed in the patent document (1) is provided with an electrolytic cell assembled therein. In the dishwasher proposed in the patent document (2), an electrolytic cell is disposed in a conduit for connection to a mineral removal device placed at an outside of the housing body of the dishwasher and to an alkaline rinse tank. The dishwasher proposed in the patent document (3) is provided with an electrolytic cell assembled in an outer box of the dishwasher only for washing. 
         [0007]    Patent document (1): Laid-open Publication for Patent No. Hei8-47473 
         [0008]    Patent document(2): Laid-open Publication for Patent No. 2003-265395 
         [0009]    Patent document(2): Laid-open Publication for Patent No. 2003-325426 
         [0010]    As the dishwashers each are provided with the electrolytic cell only for washing, the cost of the dishwasher becomes expensive. For this reason, the dishwasher with the electrolytic cell is not utilized at present despite of useful for washing. On the other hand, the electrolytic cell itself is widely used in a condition installed in a kitchen room separately from the dishwasher. In use of the electrolytic cell, electrolyzed acid water is used for sterilization of various foods and dishes, while electrolyzed alkaline water is used in a small amount for washing pollutant of the foods and dishes. 
         [0011]    The present invention was made for utilizing electrolyzed alkaline water used in a smaller amount than electrolyzed acid water produced in an electrolytic cell independently from a dishwasher. An object of the present invention is to provide a dishwasher capable of utilizing electrolyzed alkaline water produced in an electrolytic cell installed separately therefrom thereby to refrain use of detergent for washing water. 
         [0012]    According to the present invention, there is provided a control system of a dishwasher in combination with an electrolyzed water production apparatus installed independently from the dishwasher, wherein electrolyzed alkaline water stored in a washing tank from the electrolyzed water production apparatus is used as washing water at a washing process and fresh water stored in a rinse tank from a source of water is used as rinse water at a rinse process after the washing process, comprising the steps of activating the dishwasher to start operation at the rinse process so that the rinse water from the rinse tank is supplied into and stored in the washing tank; introducing the electrolyzed strong alkaline water into the washing tank in response to start of operation at the rinse process so that the alkaline water is diluted with the rinse water in the washing tank; and stopping the introduction of the electrolyzed alkaline water into the washing tank after lapse of a predetermined time. 
         [0013]    In a practical embodiment of the present invention, it is preferable that the supply of fresh water into the rinse tank is stopped during introduction of the electrolyzed alkaline water into the washing tank. It is also preferable that the supply of rinse water into the rinse tank is permitted during operation of the dishwasher at the washing process. 
         [0014]    According to an aspect of the present invention, there is provided a control system of a dishwasher in combination with an electrolyzed water production apparatus installed independently from the dishwasher, wherein electrolyzed alkaline water stored in a washing tank from the electrolyzed water production apparatus is used as washing water at a washing process and hot water stored in a rinse tank from a booster tank is used as rinse water at a rinse process after the washing process; comprising the steps of activating the dishwasher to start operation at the rinse process so that the rinse water from the rinse tank is supplied into and stored in the washing tank; introducing the electrolyzed strong alkaline water into the washing tank in response to start of operation at the rinse process so that the alkaline water is diluted with the rinse water in the washing tank; and stopping the introduction of the electrolyzed alkaline water into the washing tank after lapse of a predetermined time. 
         [0015]    In a practical embodiment of the control system, it is preferable that fresh water supplied into the booster tank is heated in a condition where the booster tank was fully filled with the fresh water. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS  
         [0016]    In the drawings: 
           [0017]      FIG. 1  is a schematic illustration of a first embodiment of a dishwasher according to the present invention; 
           [0018]      FIG. 2  is a flow chart of a control program for washing operation executed by an electric controller; 
           [0019]      FIG. 3  is a flow chart of a control program for electrolytic operation of an electrolyzed water production apparatus installed independently from the dishwasher; 
           [0020]      FIG. 4  is a schematic illustration of a second embodiment of a dishwasher according to the present invention; 
           [0021]      FIG. 5  is a flow chart of a control program for electrolytic operation of the electrolyzed water production apparatus; 
           [0022]      FIG. 6  is a schematic illustration of a third embodiment of a dishwasher according to the present invention; 
           [0023]      FIG. 7  is a flow chart of a control program for electrolytic operation of the electrolyzed water production apparatus executed by the controller in the third embodiment; 
           [0024]      FIG. 8  is a schematic illustration of a fourth embodiment of a dishwasher according to the present invention; 
           [0025]      FIG. 9  is a flow chart of a control program for washing operation executed by the controller in the fourth embodiment; 
           [0026]      FIG. 10  is a flow chart of a control program for preparation of rinse water in a booster in the fourth embodiment; and 
           [0027]      FIG. 11  is a flow chart of a control program for electrolytic operation of the electrolyzed water production apparatus in the fourth embodiment. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0028]    The present invention relates to a dishwasher of the type which is operated to effect a washing process using electrolyzed alkaline water stored in a washing tank and a rinsing process using cold or hot water stored in a rinse tank or a booster tank. The electrolyzed alkaline water is produced in an electrolytic cell of an electrolyzed water production apparatus installed separately from the dishwasher and supplied as the washing water into the washing tank. Illustrated in  FIGS. 1 ,  4  and  6  are three practical embodiments of the present invention. In  FIG. 8 , there is illustrated another practical embodiment of a dishwasher according to the present invention. 
         [0029]    In  FIG. 1 , there is schematically illustrated a first embodiment of a dishwasher A 1  according to the present invention An electrolyzed water production apparatus B 1  is installed separately from the dishwasher A 1  to produce electrolyzed alkaline water to be used as washing water in the dishwasher. The dishwasher A 1  itself is well known in the art, and the electrolyzed water production apparatus B 1  is also well known in the art. The dishwasher A 1  is provided with a washing tank  11  placed on the bottom portion of a washing chamber formed in a housing body. A washing nozzle  12  is provided above the washing tank  11 , and a rinse nozzle  13  is provided above the washing nozzle  12 . A tableware shelf  14  is mounted within the washing chamber at a position between the washing tank  11  and the washing nozzle  12 . The dishwasher A 1  is also provided with a rinse tank  15  in a mechanic chamber formed within the housing body. 
         [0030]    In operation of the dishwasher A 1 , a washing pump  11   a  is driven by an electric motor (not shown) at a washing process to supply washing water from the washing tank  11  to the washing nozzle  12  through a water supply conduit  21 . The washing water is spouted from the washing nozzle  12  for washing tableware placed on the shelf  14  and falls in the washing tank  11 . The washing pump  11   a  is operated for a predetermined time to circlate the washing water into the washing tank  11  through the washing nozzlel 2  thereby to expedite washing of the tableware. After finish of washing of the tableware in the shelf, the used washing water in the washing tank  11  is drained for subsequently starting at a rinsing process. The supply of washing water into the washing tank  11  is controlled as described later. 
         [0031]    In operation of the dishwasher A 1  at the rinsing process, a rinse pump  15   a  is driven by an electric motor (not shown) to supply cold water or hot rinse water to the rinse nozzle  13  through a water supply conduit  22 . The rinse water is spouted from the rinse nozzle  13  to rinse the washed tableware in the shelf  14  and falls in the washing tank  11 . When a predetermined amount of rinse water was spouted from the rinse nozzle  13 , the rinse pump  15   a  is stopped to finish the operation at the rinsing process. After finish of the rinsing process, an amount of fresh water is introduced into the washing tank  11 . The fresh water is supplied as rinse water through a water supply conduit  23  in connection to a tap water pipe under control of a water supply valve  24 . When the rinse tank  15  is filled with the rinse water, the water supply valve  24  is closed to stop supply of the rinse water. 
         [0032]    The electrolyzed water production apparatus B 1  installed separately from the dishwasher A 1  includes an electrolytic cell with a partition membrane which is supplied with diluted brine of a predetermined concentration to produce electrolyzed strong acid water in its anode chamber and to produce electrolyzed strong alkaline water in its cathode chamber. In this embodiment, the electrolytic condition of the brine is determined to produce electrolyzed acid water of extremely low pH about “2” and to produce electrolyzed alkaline water of extremely high pH about “12”. 
         [0033]    The electrolytic cell is provided with a discharge conduit  31  only for the electrolyzed acid water and a discharge conduit  32  only for the electrolyzed alkaline water. The discharge conduit  31  is connected to a branch conduit  33  extended above a sink  34  in a kitchen to discharge the electrolyzed acid water for germicidal washing of various foods. The discharge conduit  32  is connected to a branch conduit  25  extended above the washing tank  11  of dishwasher A 1  and connected to a branch conduit  35  through a flow changeover valve  26 . With such arrangement of the discharge conduit  32 , the electrolyzed strong alkaline water is selectively supplied to the branch conduits  25  or  35  by operation of the flow changeover valve  26 . 
         [0034]    In the dishwasher A 1 , the electrolyzed strong alkaline water produced in the electrolytic cell is introduced into the washing tank  11  through the branch conduit  25  by operation of the flow changeover valve  26  and is diluted with the rinse water in the washing tank  11  to prepare washing water of a predetermined concentration. The preparation of washing water is carried out in response to start of operation at the rinsing process in the dishwasher Al and activation of the electrolyzed water production apparatus B 1 , The introduction of the electrolyzed strong alkaline water into the washing tank  11  is started in response to start of operation at the rinsing process and stopped after lapse of a predetermined time. 
         [0035]    With such preparation of the washing water, the electrolyzed strong alkaline water is introduced into the washing tank  11 , and the rinse water is introduced into the washing tank  11  in response to start of operation at the rinsing process in the dishwasher. Thus, the electrolyzed strong alkaline water is diluted with the rinse water at the predetermined ratio and prepared as the washing water of a predetermined washing resolution. When the washing tank  11  is not filled with the washing water, the introduction of the electrolyzed strong alkaline water and the rise water is repeated until the washing tank  11  is filled with the washing water. Thus, the electrolyzed strong alkaline water produced in the electrolytic cell installed separately from the dishwasher is utilized as the washing water in the dishwasher. 
         [0036]    In the preparation of the washing water, it is preferable that supply of the rinse water into the rinse tank  15  is stopped while the electrolyzed alkaline water is being introduced into the washing tank  11 . Under such preparation of the washing water, the rinsing process is not started until the predetermined amount of the electrolyzed strong alkaline water is introduced into the washing tank  11  after finish of the preceding rinsing process. If the level of the rinse water in the rinse tank  15  is low during the washing process in the dishwasher A 1 , the rinsing process may not be started after the washing process. To avoid such trouble, the rinse water may be supplied into the rinse tank  15  during the washing process. 
         [0037]    A flow chart of a control program for washing operation of the dishwasher A 1  is shown in  FIG. 2 , and a flow chart of a control program for operation of the electrolyzed water production apparatus is shown in  FIG. 3 . When an electric controller (not shown) of the dishwasher A 1  initiates to execute the control program for washing operation, the controller determines the level of rinse water in the rinse tank  15  at step  101 . If the level of rinse water is insufficient, the controller determines a “No” answer and causes the water supply valve  24  at step  102  to open for supply of the fresh tap water into the rinse tank  15 . When the level of rinse water in the rinse tank  15  becomes sufficient, the controller determines a “Yes” answer at step  101  and determines at step  103  the level of washing water in the washing tank  11 . If the level of washing water is insufficient, the controller determines a “No” answer at step  103  and activates the rinse pump  15   a  at step  104  to supply the washing water into the washing tank. When the level of washing water becomes sufficient, the controller determines a “Yes” answer at step  103  and determines whether a washing switch (not shown) for washing operation is turned on or not. If the answer at step  105  is “No”, the controller causes the program to return to step  101 . When the washing switch is turned on, the controller determines a “Yes” answer at step  105  and activates the washing pump  11   a  at step  106  to start operation at the washing process. After lapse of a predetermined time, the controller deactivates the washing pump  11   a  and causes a drain valve (not shown) to discharge the washing water from the washing tank  11 . Thereafter, the controller activates the rinse pump  15   a  at step  107  to start operation at the rinse process and returns the program to step  101  after finish of the rinse process. 
         [0038]    When the dishwasher A 1  is activated to start operation at the rinse process, the controller activates the electrolyzed water production apparatus B 1  and executes the control program for electrolytic operation shown by a flow chart in  FIG. 3 . When detected the operation of the rinse pump  15   a  at step  201 , the controller turns on a start switch (not sown) of the electrolyzed water production apparatus B 1  and switches over the flow changeover valve  26  to start the activation of the electrolyzed water production apparatus B 1  at step  202 . Subsequently, the controller closes the water supply valve  24  at step  203  to stop the supply of water into the rinse tank  15 . Thus, the operation of the dishwasher at the rinse process is continued for a predetermined time at step  204 . Upon lapse of the predetermined time, the controller causes the water supply valve  24  at step  205  to open for restart of supply of the water into the rinse tank  15  and deactivates the electrolyzed water production apparatus B 1  at step  206 . 
         [0039]    With such preparation of the washing water, the washing tank  11  is supplied with the electrolyzed strong alkaline water from the electrolyzed water production apparatus B 1  activated at the rinse process of the dishwasher A 1  and is supplied with rinse water used at the rinse process. As a result, the electrolyzed strong alkaline water is diluted with the rinse water at a predetermined ratio so that the washing water of desired washing resolution is prepared with a stable characteristic. Thus, the electrolyzed strong alkaline water produced in the electrolyzed water production apparatus installed separately from the dishwasher A 1  can be utilized as the washing water in the dishwasher A 1 . 
         [0040]    Illustrated in  FIG. 4  is a second embodiment of a dishwasher A 2  according to the present invention. In this second embodiment, a neutralization tank  36  is disposed in a drain conduit  37  bifurcated from the branch conduit  33  extending into the sink  34 , and a second changeover valve  37   a  is disposed in the bifurcated portion of branch conduit  33 . The dishwasher A 2  is the same as the dishwasher in the first embodiment, and an electrolyzed water production apparatus B 2  is the same as the electrolyzed water production apparatus B 1  in the first embodiment. The neutralization tank  36  is provided to store an amount of calcium carbonate for increasing pH of electrolyzed acid water and an amount of activated carbon, sodium thiosulfate or the like for eliminating chlorine component. The second changeover valve  37   a  is provided with an on-off switch (not shown) to be activated under control of the controller. When the on-off switch is turned on, the changeover valve  37   a  is switched over to connect the discharge conduit  31  to the branch conduit  33 . When the on-off switch is turned off, the changeover valve  37   a  is switched over to connect the discharge conduit  31  to the drain conduit  37 . The electrolyzed water production apparatus B 2  is. activated while the on-off switch of changeover switch  37   a  is maintained in its on-position. 
         [0041]    In this embodiment, the controller executes the program for washing operation shown in  FIG. 2  to operate the dishwasher A 2  in the same manner as in the first embodiment. On the other hand, the electrolyzed water production apparatus is operated under execution of a control program for electrolytic operation shown by a flow chart in  FIG. 5 . 
         [0042]    To prepare washing water in the washing tank  11 , the controller executes processing at step  201 ˜ 206  of the control program for electrolytic operation in the same manner as in the control of the electrolyzed water production apparatus B 1  of the first embodiment. After preparation of the washing water in the washing tank  11 , the controller turns on the on-off switch of second changeover valve  37   a  at step  207  to connect the discharge conduit  31  to the branch conduit  33  and executes the processing at step  202  to activate the electrolyzed water production apparatus B 2 . After start of the electrolytic operation, the controller turns off the on-off switch of second changeover valve  37   a  at step  208  to connect the discharge conduit  31  to the drain conduit  37  in connection to the neutralization tank  36 . 
         [0043]    With such execution of the control program for electrolytic operation, the electrolyzed strong acid water produced in the electrolyzed water production apparatus B 2  during supply of the electrolyzed strong alkaline water into the washing tank  11  of dishwasher A 2  is introduced into the neutralization tank  36 . Thus, the electrolyzed strong acid water is neutralized in the neutralization tank  36  and drained without causing any difficulty in the water. 
         [0044]    Illustrated in  FIG. 6  is a third embodiment of a dishwasher A 3  according to the present invention. In this third embodiment, an introduction conduit  38  for supply of tap water into the discharge conduit  33  extending into the sink  34 , and a second water supply valve  38   a  is disposed in the introduction conduit  38  is provided. In an electrolytic cell B 3  for the dishwasher A 3 , electrolyzed strong alkaline water of about pH 12 is produced for preparation of washing water to be used in the dishwasher A 3 , while electrolyzed strong acid water of pH 2 is produced. As pH of the electrolyzed strong acid water is low, the chlorine component contained in the acid water volatilizes as chlorine gas due to vibration applied thereto. This causes corrosion of surrounding metallic parts. It is, therefore, desirable to increase pH of the electrolyzed acid water used in the sink up to 2.6˜3.5 for restraining the occurrence of chlorine gas. For this reason, when the electrolyzed strong acid water is used in the sink  34 , the second water supply valve  38   a  is opened to introduce fresh tap water into to the acid water flowing the discharge conduit  33  thereby to increase pH of the acid water to about 2.6˜3.5. 
         [0045]    In this third embodiment, the controller executes the control program for washing operation shown in  FIG. 2  in the same manner as in the first embodiment. On the other hand, the electrolyzed water production apparatus B 3  is operated under execution of a control program for electrolytic operation shown by a flow chart in  FIG. 7 . 
         [0046]    To prepare washing water in the washing tank  11 , the controller executes processing at step  201 ˜ 206  of the control program for electrolytic operation in the same manner as in the control of the electrolyzed water production apparatus B 1  of the first embodiment. In this instance, the controller switches over the changeover valve  37   a  at step  207  to connect the discharge conduit  31  to the branch conduit  33 , opens the second water supply valve  38   a  at step  209  and executes the processing at step  202  to activate the electrolyzed water production apparatus B 3 . When the changeover valve  37   a  is switched over at step  208  to connect the discharge conduit  31  to the drain conduit  37  after start of the electrolytic operation, the controller closes the second water supply valve  38   a  to stop supply of the fresh water from the introduction conduit  38  into the branch conduit  33 . 
         [0047]    Illustrated in  FIG. 8  is a fourth embodiment of a dishwasher A 4  according to the present invention. In this fourth embodiment, a booster  16  is installed outside the housing body of dishwasher A 4  for supplying hot water as rinse water into the rinse nozzle  13  by operation of the rinse pump  15   a.  The booster  16  is in the form of a booster tank  16   a  of the water heater type which is supplied with fresh water from the water supply conduit through the water supply valve  24 . When the level of fresh water stored in the booster tank  16   a  becomes a predetermined level, the fresh water is heated and supplied as hot rinse water into the rinse nozzle  22  in operation of the rinse pump  15   a.    
         [0048]    A control program for washing operation in the dishwasher A 4  is shown by a flow chart in  FIG. 9 , and a control program for preparation of rinse water is shown by a flow chart in  FIG. 10 . In addition, a control program for electrolytic operation of an electrolyzed water production apparatus B 4 . In operation of the dishwasher A 4 , the controller determines at step  111  of the control program whether the level of fresh water in the booster tank  16   a  is the predetermined full level or not. If the answer at step  111  is “No”, the controller will stand by for supply of fresh water at step  112  for a predetermined time. When the answer at step  111  becomes “Yes”, the controller determines at step  113  whether the amount of water in the washing tank  11  is sufficient or not. If the answer at step  113  is “No”, the controller activates the rinse pump  15   a  to supply hot rinse water from the booster tank  16   a  into the rinse nozzle  13  and returns the program to step  111 . When the answer at step  113  becomes “Yes”, the controller determines at step  115  whether the switch for washing operation is turned on or not. If the answer at step  115  is “No”, the controller returns the program to step  111 . When the switch for washing operation is turned on, the controller activates the washing pump  11   a  at step  116  to start operation at a washing process. When the operation at the washing process stops after lapse of a predetermined time, the controller opens a drain valve (not shown) of the washing tank  11  to drain the used washing water. Thereafter, the controller activates the rinse pump  15   a  at step  117  to start operation at a rinse process and returns the program to step  111  after finish of the operation at the rinse process. 
         [0049]    During such operation of the washing pump  11   a  and rinse pump  15   a,  the controller starts to execute the control program for preparation of rinse water shown in  FIG. 10 . At step  301 , the controller determines whether the level of fresh water in the booster tank  16   a  is sufficient or not. If the answer at step  301  is “No”, the controller opens the water supply valve  24  at step  302  and is maintained on standby for supply of fresh water from the source of water into the booster tank  16   a.  When the booster tank  16   a  is fully filled with the fresh water, the controller determines a “Yes” answer at step  301  and causes the program to proceed to step  303 . When received at step  303  a signal indicative of the fact that the booster tank  16   a  is fully filled with the fresh water, the controller determines at step  304  whether the water temperature in booster tank  16   a  rises up to a predetermined value or not. If the answer at step  304  is “No”, the controller causes the booster tank  16   a  at step  305  to heat the fresh water stored therein and returns the program to step  301 . If the answer at step  304  is “Yes”, the controller returns the program to step  301 . 
         [0050]    On the other hand, the controller executes the control program for electrolytic operation shown in  FIG. 11 . When detected the operation of rinse pump  15   a  at step  211 , the controller activates the electrolyzed water production apparatus B 4  at step  212  and cancels at step  213  the signal indicative of the fact that the booster tank  16   a  is fully filled with the fresh water. Subsequently, the controller maintains at step  214  the activated condition of the electrolyzed water production apparatus for a predetermined time. After lapse of the predetermined time, the controller releases the cancel of the signal from the booster tank  16   a  at step  215  and deactivates the electrolyzed water production apparatus.