Patent Publication Number: US-2009235465-A1

Title: Method for operating a domestic appliance, especially a home dryer or a washing machine, and domestic appliance

Description:
The invention concerns a method for operating a domestic appliance and a domestic appliance, especially a home dryer or a washing machine, 
     Home dryers and washing machines are well known in the state of the art. In relation to home dryers it is thereby known to dry textiles using a condensation process or using a wet exhausting air process. 
     It has been found out that the treatment of textiles can be improved by using steam which is applied to the textiles e.g. in a dryer during one operation mode of the dryer. One aspect of such a process is to prepare the textiles in a better way for the following ironing. Another aspect is to remove unwanted odours out of the textiles. 
     The dryer comprises as a rule a rotatable drum in which the textiles are contained when the textiles are treated with hot water steam. The steam generated by a steam unit is conducted by a conduit and a steam injector into the drum. The steam has, during the operation in the drum normally a temperature of equal or more than 100° C. Opening the door used for loading and un-loading the drum of the dryer with textiles during the run of a program for treating textiles with steam can-therefore be dangerously for an operator. 
     It is therefore an object of the present invention to propose a method for operating a domestic appliance and a domestic appliance as mentioned above which at least reduce the risk of an accident with hot steam during the operation of the domestic appliance. 
     This object is inventively achieved by the method for operating a domestic appliance, especially a home dryer or a washing machine, of claim  1 , which domestic appliance comprises a steam unit and an operating mode for treating textiles with hot steam, wherein at least one action for protection of an operator of the domestic appliance is taken when an interruption of an active program for treating textiles with hot steam occurs. The inventors have recognized that every interruption of a program for treating textiles with steam should be supervised because independently thereof whether the interruption was caused by the operator or not there is always potentially the danger that the operator opens the door of the domestic appliance without thinking about the hot steam inside the domestic appliance. It is therefore reasonable to provide at least one preferably more actions that the operator is not hurt by the hot steam generated in the domestic appliance, when an interruption of a run of a program for treating textiles with hot steam occurs. 
     According to one variant of the invention the action is taken, when a door for loading and un-loading a room of the domestic appliance with textiles is opened, whereby the opening of the door interrupts the program for treating the textiles with steam. Normally the domestic appliance has a door to a rotatable drum containing the textiles during the operation of the domestic appliance. The door comprises a mechanism for opening and closing the door. It is proposed to have sensing means working together with the mechanism for opening and closing the door. Preferably the sensing means are connected with control means of the domestic appliance. The control means finally initiate the action for the protection of the operator, when the door is opened during a run of a program for treating the textiles with steam. 
     According to another variant of the invention the action is taken, when the program for treating textiles with steam is interrupted by activation of a switching equipment of the domestic appliance. The switching equipment comprises preferred a stop-button or a start/rest-button. Theses buttons are as a rule part of a operating panel of the domestic appliance. The switching equipment can also be a kind of virtual button e.g. a button displayed on a screen e.g. displayed on a touch screen. 
     The action is also taken, when the run of the program for treating textiles with steam is interrupted by a failure of the domestic appliance. Such a failure can be e.g. a short interruption of the supply voltage of the domestic appliance which can cause the interruption of the run of the program for treating textiles with steam. 
     A preferred action is to release at least one warning signal to the operator which calls the operator&#39;s attention to the hot steam inside the domestic appliance especially inside the drum. The warning signal can be an acoustic and/or an optical warning signal. When the warning signal is an optical warning signal it is preferred displayed with an optical display, which comprises a lamp or a LED-display (light emitting diode) or the operating panel of the domestic appliance, which operating panel comprises particularly a LCD-display (liquid crystal display). 
     Another action for protection of an operator is to stop at least partially the supply of steam to the room, particularly to the drum of the domestic appliance containing the textiles, when an interruption of a run of a program for treating textiles with steam occurs. Thereby the control means of the domestic appliance stop as a rule the activity of the steam unit, in particular the activity of the pump of the steam unit and/or the heating of the steam generator. 
     According to variants of the invention the supply of steam to the room of the domestic appliance containing the textiles can be at least partially stopped by closing a conduit which is used for supplying the room with steam. The conduit can thereby be closed by a valve, preferred by a magnetic valve. 
     Another possibility according to the invention to protect an operator is to deplete the steam unit of the domestic appliance of steam at least partially, when an interruption of a run of a program for treating textiles with steam occurs. This can be achieved by a valve, preferred a magnetic valve. Preferably the opening and closing of the valve is controlled by the control of the domestic appliance. The steam is thereby conducted in a part or in parts of the domestic appliance to which the operator has as a rule no contact or no access. 
     According to embodiments of the invention the supply of steam to the room of the domestic appliance containing the textiles can be at least partially stopped by the reversion of the flux of the steam through the steam unit. By a reversion of the flux of the steam through the steam unit thus the steam do not flow through a conduit and an injector in direction to the room containing the textiles but flows in the opposite direction. Preferred the pump of the steam unit which normally pumps water out of a water tank into the steam generator of the steam unit is thereby operated in a reversed mode. In the reversed mode the pump of the steam unit is operated in an opposite direction and pumps the steam already generated in the steam generator into the water tank. 
     It is also possible for the protection of the operator to conduct the steam contained in the drum of the domestic appliance out of the drum, when an interruption of a run of a program for treating textiles with steam occurs. This can be achieved by a separate conduit connected with one side to the drum and with the other side e. g. to the outside of the domestic appliance. Preferably there is a controllable valve for opening the passage through the conduit. Advantageously a fan is used for conducting the steam out of the drum containing the textiles. Another possibility for conducting the steam out of the drum of the domestic appliance is to use an already existing conduit of the domestic appliance. Preferred is the use of the conduit of the supply air to the drum and/or the use of the conduit of the exhaust air out of the drum. Both conduits are normally used for air circulation during the process of drying textiles. The last mentioned embodiment is therefore particularly adapted for home dryers. 
     According to an embodiment of the invention the door for loading and un-loading the domestic appliance with textiles can not be opened after an interruption of an active program for treating textiles with steam until there is no more danger for an injury of an operator. Preferred the door for loading and un-loading the domestic appliance with textiles can not be opened for a certain period of time and/or until the temperature and/or the atmospheric moisture in the room of the domestic appliance containing the textiles has/have a certain value. The opening of the door is in these cases thus either time controlled or temperature controlled or atmospheric moisture controlled. 
     The domestic appliance can be in case of a dryer a dryer of the condensation type or a dryer of the exhaust air type. 
     The domestic appliance according to the invention comprises a control and a memory storing at least one program for treating textiles with steam, wherein 
     the control is adjusted to execute at least one of the aforementioned methods. 
    
    
     
       Embodiments of the invention are illustrated in the accompanying schematic drawings. It is shown: 
         FIG. 1  a dryer in a front view, 
         FIG. 2  a first embodiment of components of the dryer of  FIG. 1 , partially shown in a schematic block diagram and 
         FIG. 3  a second embodiment of components of the dryer of  FIG. 1 , partially shown in a schematic block diagram. 
     
    
    
     The invention is consecutively exemplarily described for a domestic appliance in form of a home dryer. But the domestic appliance according to the invention can also be a washing machine comprising a steam unit as described later and an operating mode for treating textiles with steam. 
       FIG. 1  shows a front view of a dryer, especially a home dryer  1 .  FIG. 2  shows in one embodiment of the invention components of the home dryer  1  of  FIG. 1 . The home dryer  1  of  FIG. 1  and  FIG. 2  is a condensation type dryer. The home dryer  1  comprises a housing  2  with a door  3  for loading and un-loading a drum  4  with not shown textiles. The drum  4  is rotatable around an axis A by means of a motor  5  and a belt  6 . The drum  4  is in a not shown way respectively pivoted. 
     For drying textiles the home dryer  1  comprises a conduit  7  for the supply air to the drum  4 , a heating element  8  in case of the on hand embodiment arranged in or near the conduit  7  for the supply air, a conduit  9  for the exhausted air, a heat exchanger  10 , a sump  11 , a pump  12 , a water tank or condensate collector  13 , a first fan  14  in case of the on hand embodiment arranged in the conduit  7  for the supply air and a second fan  15  arranged near the heat exchanger  10 . The first fan  14  and the second fan  15  are connected to a drive motor  16 . 
     Further the home dryer  1  comprises an operating panel  30  with an display  31  and a turning knob  32  for choosing a program for drying textiles and/or a program for treating textiles with steam. The operating panel  30  is connected to control means in form of a control  40  of the home dryer  1 . The control  40  is preferably a program driven computer and comprises a memory  41 . A plurality of different programs for drying textiles and programs for treating textiles with steam is stored in the memory  41  which can be chosen with the turning knob  32 . The display  31  is preferably a LCD-display. The display  31  is particularly intended for displaying program information and operating data of the home dryer  1 . The knob  32  and the display  31  can also be used for setting operating parameters of the home dryer  1 . 
     In one operation mode of the home dryer  1 , when a program for drying textiles is chosen by an operator with the turning knob  32  of the operating panel  30  the home dryer  1  is operated in an air circulation mode. Thereby air heated by the heating element  8  in the conduit  7  for the supply air is applied by means of the fan  14  to wet textiles contained in the rotating drum  4 . In the drum  4  the heated air is charged with moisture. The air charged with moisture arrives by means of the conduit  9  for the exhausted air at the heat exchanger  10  which is cooled with the fan  15 . Water condenses in the heat exchanger  10  and is collected in the sump  11 . The pump  12  pumps the water of the sump  11  into the condensate collector  13 . Now the air is again heated and conducted by means of the fan  14  into the drum  4 . This air circulation process continues until the textiles in the drum  4  are dried in an adequate manner. The run of the chosen program for drying textiles is controlled by the control  40  of the home dryer  1  which is particularly connected to the motor  5 , the heating element  8 , the motor  16  and the pump  12  what is not explicitly shown in  FIG. 2 . 
     In another operation mode of the home dryer  1  textiles contained in the drum  4  can be treated with hot water steam. The home dryer  1  comprises therefore a steam unit. The steam unit comprises a water tank  20 , a pump  21 , a steam generator  22  and a injector  23  for the steam connected to the steam generator  22  by a conduit  24 . As described above the operator can choose a program for treating textiles with steam with the turning knob  32 . During the run of such a program water contained in the water tank  20  is pumped by the pump  21  into the steam generator  22  and there heated. The steam generated in the steam generator  22  arrives by means of the conduit  24  and the injector  23  at the drum  4 . The hot water steam is then applied to the textiles contained in the drum  4 , which thereby rotates around the axis A. The hot water steam has a temperature of 100° C. and more. This process particularly the run of the respective program is again controlled by the control  40 . 
     Especially during the run of a program for treating textiles with hot steam the danger exists that an operator is hurt by the hot steam when an active program is interrupted. Normally an interruption of a run of program for treating textiles with steam is caused either by opening the door  3  for loading and unloading the drum  4  with textiles or by switching of a switching equipment of the home dryer  1 . But an interruption of a run of a program for treating textiles with steam can also occur in consequence of a failure of the home dryer  1 . By the way this listing is not concluding. 
     For detecting the opening of the door  3  for loading and unloading the drum  4  with textiles as soon as possible a mechanism  17  for opening and closing the door  3  is equipped with additional sensing means  18 . The sensing means  18  are e. g. a light barrier or any other appropriate sensor for registering at once the opening of the door  3  with the mechanism  17 . The sensing means  18  are connected to the control  40  (not shown in the drawings). Therefore the control  40  can at once register when the door  3  is opened. 
     As mentioned above the run of a program for treating textiles with steam can also be interrupted by the activation of switching means. Switching means for such an interruption are in the case of the on hand embodiment a stop-button  33  and/or a start/rest-button  34  of the operating panel  30  of the home dryer  1 . The switching of any of these buttons is registered by the control  40 . 
     In any case of interruption of a run of a program for treating textiles with steam, especially in the aforementioned cases, it is reasonable to take at least one action for protection of the operator. It is namely possible that the operator is not aware of the hot steam inside the drum  4  when the interruption occurs. 
     When the control  40  registers an interruption of a run of a program for treating textiles with steam is it by means of the sensing means  18  or by getting a stop signal or rest signal based on the activation of the stop-button  33  or of the start/rest-button  34  the control  40  runs in a kind of emergency mode and releases at once at least one warning signal. Preferably an acoustic and an optical warning signal are released or generated by the control  40  to direct the operator&#39;s attention to the hot steam inside the drum  4 . 
     The acoustic warning signal is released e.g. by means of a buzzer or a speaker  35  of the operating panel  30  to the operator. The warning signal can be e.g. a beep or a spoken warning like “attention—hot steam”. 
     The optical warning signal is released by means of an optical display preferably arranged in the front of the home dryer  1 . 
     The optical display can be e.g. a lamp, particularly a red lamp  36  or a LED-display or the LCD-display  31 . The optical warning signal can thus be only a red warning light or in case of the LCD-display  31  red blinking words like “attention—hot steam”. 
     Additionally to the release of the warning signals the control  40  stops after registering an interruption of a run of a program for treating textiles with steam the further supply of hot steam of the steam unit to the drum  4 . The control  40  especially stops the operation of the pump  21  of the steam unit and the operation of the heating of the heat generator  22  of the steam unit. 
     The supply of steam to the drum  4  can thereby be stopped by closing the conduit  24  by a magnetic valve  25  which is attached to the conduit  24  and controlled by the control  40 . 
     A further possibility to stop the supply of steam to the drum  4  containing the textiles can be the reversion of the flux of the steam through the steam unit. By a reversion of the flux of the steam through the steam unit thus the steam generated by the steam generator  22  do not flow through the conduit  24  and the injector  23  in direction to the drum  4  but flows in the opposite direction. The pump  21  of the steam unit which normally pumps water out of a water tank  20  into the steam generator  22  is thereby preferably operated in a reversed mode. In the reversed mode the pump  21  is operated in an opposite direction and pumps the steam already generated and still present in the steam generator  22  into the water tank  20 . The pump  21  is thereby controlled by the control  40 . 
     Another action to protect an operator is to deplete the steam unit of the home dryer  1  of the steam, when an interruption of a run of a program for treating textiles with steam occurs. This can be achieved by a magnetic valve  26  attached to the steam unit. E.g. the magnetic valve  26  is attached to a conduit connecting the pump  21  und the steam generator  22 . The opening and closing of the magnetic valve  26  is controlled by the control  40 . When an interruption of a run of a program for treating textiles with steam occurs, the magnetic valve  26  is opened in direction to a conduit  27  which is attached to the magnetic valve  26  and the steam is conducted by means of the conduit  27  in a part or in parts of the home dryer  1  to which the operator has as a rule no contact or no access. 
     When the conduit  27  is connected to the magnetic valve  25  the steam unit can also be depleted of the steam by means of the magnetic valve  25  and the conduit  27 . In this case the magnetic valve  26  is not necessary. 
     Another action taken by the control  40  in case of an interruption of a run of a program for treating textiles is to conduct as fast as possible the hot steam contained in the drum  4  out of the drum  4 . This can be done by a separate conduit connected to the drum  4  and equipped with a controllable valve. But preferably the conduit  7  for the supply air and/or the conduit  9  for the exhausted air are used for conducting the hot steam out of the drum  4 . In case of the on hand embodiment the conduit  7  for the supply air is used because of the fan  14  inside the conduit  7 . So the control  40  can activate the motor  16  in such a way that the hot steam is conducted out of the drum  4  by means of the fan  14  which is operated in the reverse direction in comparison to the drying mode (see arrow in  FIG. 2 ). 
     In case of an interruption of a run of a program for treating textiles with steam by switching one of the buttons  33  or  34  the control  40  blocks the door  3  with a not explicitly shown closing device of the mechanism  17 . The door  3  can thereby not be opened until there is no more danger for an injury for the operator. Preferably the door  3  is blocked by the control  40  for a certain period of time, e.g. 1 minute, and/or until the temperature and/or the atmospheric moisture in the drum  4  has reached a certain value. The value of the temperature can be registered with a separate temperature sensor  19  connected to the control  40  or in a respectively way with a not shown temperature sensor of the steam generator  22  whereby based on the temperature of the steam generator  22  and a known cool down behaviour of the steam in the drum  4  the control  40  computes the temperature in the drum  4 . The value of the atmospheric moisture can be registered with a separate sensor  28  connected to the control  40  or with a already existing sensor of the home dryer  1 . 
     The invention was afore described in connection with a home dryer of the condensation type. But the invention is not limited to home dryer of the condensation type. The invention is also applicably in home dryers using a wet exhausted air process as illustrated in  FIG. 3 . Components shown in  FIG. 3  which are in type and function identically or comparably with components shown in  FIG. 2  have the same reference numerals. 
     In case of the embodiment of  FIG. 3  heated air is conducted in the drum  4  by means of the conduit  7  for supply air, the heating element  8  and the fan  14  for drying wet textiles contained in the drum  4 . The air charged with moisture is conducted from the drum  4  to the outside of the home dryer. 
     The home dryer of  FIG. 3  can like the home dryer of  FIG. 2  be operated with at least one program for treating textiles in the drum  4  with hot steam. For protection of an operator in case of an interruption of a program for treating textiles with steam the same actions can be taken as described above. Acoustic and optical warning signals can be released in the same way. The supply of steam to the drum  4  can be stopped by the control  40 . The steam unit can be depleted of steam. The steam contained in the drum  4  can be conducted out of the drum by means of the conduit  7  and the fan  14  whereby the fan can be operated in both turning direction. Also the door  3  can be blocked for a certain period of time and/or until the temperature in the drum  4  has reached a certain value. 
     As mentioned before the invention is also applicable to washing s machines comprising a steam unit and an operating mode for treating textiles with hot steam. 
     As described above a lot of actions can be taken in case of an interruption of a run of a program for treating textiles with steam for the protection of an operator. Thereby it is not necessary to take all the described actions. It can be sufficient to take only one action or any adapted combination of the described actions that the operator is not hurt by hot steam. 
     REFERENCE NUMERALS 
       1  home dryer 
       2  housing 
       3  door 
       4  drum 
       5  motor 
       6  belt 
       7  conduit for supply air 
       8  heating element 
       9  conduit for exhausted air 
       10  heat exchanger 
       11  sump 
       12  pump 
       13  condensate collector 
       14  fan 
       15  fan 
       16  motor 
       17  mechanism 
       18  sensing means 
       19  temperature sensor 
       20  water tank 
       21  pump 
       22  steam generator 
       23  injector 
       24  conduit 
       25  magnetic valve 
       26  magnetic valve 
       27  conduit 
       28  sensor 
       30  control panel 
       31  display 
       32  turning knob 
       33  stop-button 
       34  start/rest-button 
       35  speaker 
       36  lamp 
       40  control 
       41  memory 
     A axis