Method for operating a dishwasher configured as a program-operated machine, and a corresponding dishwasher

Abstract

In order to reduce the fresh water or final-rinse liquid quantity necessary to clean items without impairing the effectiveness of the cleaning, it is provided that, during an adsorption phase, air is led out of the treatment chamber of the machine through a sorption unit such that moisture is absorbed from the air flow by a dry material, after which the air is fed back to the treatment chamber. During a desorption phase, the dry material is heated and air is led out of the treatment chamber through the heated dry material such that moisture is desorbed from the dry material and at least a part of the desorbed moisture is discharged as steam from the sorption unit. At least a part of the steam discharged from the sorption unit is led into the treatment chamber during a steam final-rinse phase.

1 . A method for operating a dishwasher ( 1 ) configured as a program-operated machine, which dishwasher has a treatment chamber ( 2 ) for receiving wash items to be cleaned, wherein the method has the following method steps:
 i) during an adsorption phase, air is led out of the treatment chamber ( 2 ) through a sorption unit ( 41 ) having a reversibly dehydratable dry material such that the dry material absorbs moisture from the air flow, after which the air is fed back to the treatment chamber ( 2 ); and   ii) during a desorption phase, the dry material of the sorption unit ( 41 ) is heated and air is led out of the treatment chamber ( 2 ) through the sorption unit ( 41 ) having the heated dry material such that moisture is desorbed from the dry material and at least a part of the thermal energy previously introduced into the dry material, and at least a part of the moisture desorbed from the dry material, is discharged as steam from the sorption unit ( 41 ) with the aid of the air flow led through the sorption unit ( 41 ),   wherein at least a part of the steam discharged from the sorption unit ( 41 ) in method step ii) is led into the treatment chamber ( 2 ) during a steam final-rinse phase.   
     
     
         2 . The method as claimed in  claim 1 ,
 wherein in method step ii) the dry material of the sorption unit ( 41 ) is heated by a supply of thermal energy, and wherein, with a time lag, or simultaneously with the thermal energy supply, the air is led out of the treatment chamber ( 2 ) through the sorption unit ( 41 ).   
     
     
         3 . The method as claimed in  claim 1 ,
 wherein the method further has the following program-controlled method steps, which are executed consecutively:   a) during a wash phase, wash liquid is sprayed from a tank ( 12 ) with the aid of a wash pump ( 13 ) via a wash pipe system ( 16 ) through wash nozzles ( 11   a ,  11   b ) into the treatment chamber ( 2 ), wherein at least a part of the sprayed wash liquid flows back from the treatment chamber ( 2 ) by gravity into the tank ( 12 ); and   b) during a final-rinse phase, final-rinse fluid is led into the treatment chamber ( 2 ), wherein the final-rinse phase is composed of a fresh water final-rinse phase, in which a final-rinse liquid is sprayed with the aid of at least one final-rinse pump ( 14 ;  14   a ,  14   b ) through a final-rinse pipe system ( 17 ,  17   a ,  17   b ) into the treatment chamber ( 2 ) and at least a part of the sprayed final-rinse liquid flows back from the treatment chamber ( 2 ) by gravity into the tank ( 12 ), and the steam final-rinse phase, in which at least a part of the steam discharged from the sorption unit ( 41 ) in method step ii) is led into the treatment chamber ( 2 ).   
     
     
         4 . The method as claimed in  claim 3 ,
 wherein the steam final-rinse phase begins after the completion of the fresh water final-rinse phase.   
     
     
         5 . The method as claimed in  claim 3 ,
 wherein the steam final-rinse phase is performed in advance of the fresh water final-rinse phase.   
     
     
         6 . The method as claimed in  claim 3 ,
 wherein the steam final-rinse phase and the fresh water final-rinse phase chronologically overlap at least partially.   
     
     
         7 . The method as claimed in  claim 3 ,
 wherein the steam final-rinse phase occupies a period of 10 to 30 seconds.   
     
     
         8 . The method as claimed in  claim 3 ,
 wherein, during the steam final-rinse phase, a total of 40 to 70 g water is fed in the vaporous state to the treatment chamber ( 2 ).   
     
     
         9 . The method as claimed in  claim 3 ,
 wherein the method further has the following program-controlled method steps:   c) during a condensation and draining phase, which takes place after the completion of the steam final-rinse phase, the steam introduced during the steam final-rinse phase into the treatment chamber ( 2 ) condensates at least partially and the thereby formed condensate flows off by gravity at least partially out of the treatment chamber ( 2 ).   
     
     
         10 . The method as claimed in  claim 9 ,
 wherein the method further has the following optional method step:   d) during a drying phase, which takes place after the completion of the condensation and draining phase, an air circuit is formed in the treatment chamber ( 2 ) for the drying of wash items accommodated in the treatment chamber ( 2 ),   wherein at least a part of the drying air circulating in the treatment chamber ( 2 ) is led through the sorption unit ( 41 ) having the reversibly dehydratable dry material and is subsequently fed back to the treatment chamber ( 2 ).   
     
     
         11 . The method as claimed in  claim 10 ,
 wherein method step i) is simultaneous or chronologically overlapping with the drying phase.   
     
     
         12 . The method as claimed in  claim 3 ,
 wherein method step ii) is performed directly before or simultaneously with the final-rinse phase, in particular steam final-rinse phase.   
     
     
         13 . A dishwasher ( 1 ) configured as a program-operated machine, comprising:
 a treatment chamber ( 2 ), into and from which wash items can be manually inserted and removed;   a tank ( 12 ), into which liquid can flow off from the treatment chamber ( 2 ) by gravity;   a wash system having a wash pump ( 13 ) and a wash pipe system ( 16 ) for conveying wash liquid out of the tank ( 12 ) during a wash phase and for spraying the wash liquid through wash nozzles ( 11   a ,  11   b ) in the treatment chamber ( 2 );   a fresh water final-rinse system having at least one final-rinse pump ( 14 ;  14   a ,  14   b ) and at least one final-rinse pipe system ( 17 ,  17   a ,  17   b ) for conveying final-rinse liquid out of a fresh water feed device during a fresh water final-rinse phase and for spraying the final-rinse liquid through final-rinse nozzles ( 15   a ,  15   b ) in the treatment chamber ( 2 );   a steam final-rinse system for generating steam and for leading the steam into the treatment chamber ( 2 ) during a steam final-rinse phase; and   a program control device ( 101 ) for executing at least one cleaning program, the program control device ( 101 ) being configured such that, in a cleaning cycle, first the wash phase, and afterwards the fresh water final-rinse phase and the steam final-rinse phase, are carried out,   wherein the steam final-rinse system has a sorption unit ( 41 ), having a reversibly dehydratable dry material, a fan ( 44 ) for the formation of an air circuit, such that at least a part of the air is led out of the treatment chamber ( 2 ) through the sorption unit ( 41 ) and subsequently fed back to the treatment chamber ( 2 ), and a heating device ( 45 ), for heating the dry material during a desorption phase of the sorption unit ( 41 ).   
     
     
         14 . The dishwasher ( 1 ) as claimed in  claim 13 ,
 wherein the heating device ( 45 ) assigned to the sorption unit ( 41 ) is designed to, during the desorption phase, through the supply of electrical energy and/or heat, heat the dry material of the sorption unit ( 41 ) such that moisture previously absorbed by the dry material is at least partially released again by the dry material.   
     
     
         15 . The dishwasher ( 1 ) as claimed in  claim 13 ,
 wherein the dry material has type Y zeolite.   
     
     
         16 . The dishwasher ( 1 ) as claimed in  claim 13 ,
 wherein the program control device ( 101 ) is designed to, during the steam final-rinse phase, initiate the desorption phase of the sorption unit ( 41 ) by activation of the heating device ( 45 ) and feeding of thermal energy to the dry material, and by switching on of the fan ( 44 ) such that air is led out of the treatment chamber ( 2 ) through the sorption unit ( 41 ) having the heated dry material, so that moisture is desorbed from the dry material and at least a part of the thermal energy previously introduced into the dry material, as well as at least a part of the moisture desorbed from the dry material, with the aid of the air flow led through the sorption unit ( 41 ), is discharged as steam from the sorption unit ( 41 ) and introduced into the treatment chamber ( 2 ).   
     
     
         17 . The dishwasher ( 1 ) as claimed in  claim 13 ,
 wherein the program control device ( 101 ) is designed to, during a drying phase, initiate an adsorption phase of the sorption unit ( 41 ) by switching on of the fan ( 44 ) such that air is led out of the treatment chamber ( 2 ) through the sorption unit ( 41 ), so that the dry material of the sorption unit ( 41 ) absorbs moisture from the air flow, after which the air is fed back to the treatment chamber ( 2 ).   
     
     
         18 . The dishwasher ( 1 ) as claimed in  claim 13 , wherein the fresh water feed device has a fresh water container ( 6 ), which is connected to a fresh water supply pipe ( 30 ) and the outlet of which is connected to the suction side of the at least one final-rinse pump ( 14 ;  14   a ,  14   b ). 
     
     
         19 . The dishwasher ( 1 ) as claimed in  claim 13 , wherein the fresh water feed device has a boiler ( 22 ) connected to a fresh water supply pipe ( 30 ), for warming the final-rinse liquid to be pumped into the treatment chamber ( 2 ) during the fresh water final-rinse phase, the outlet of the boiler being connected to the suction side of the at least one final-rinse pump ( 14 ;  14   a ,  14   b ). 
     
     
         20 . The dishwasher ( 1 ) as claimed in  claim 13 ,
 wherein the steam final-rinse system further has a steam generator ( 39 ), connected to a fresh water supply pipe ( 30 ), for generating additional steam during the steam final-rinse phase, the steam generator ( 39 ) being connected by a steam pipe ( 40 ) to the treatment chamber ( 2 ) in order to introduce the additionally generated steam into the treatment chamber ( 2 ).   
     
     
         21 . The dishwasher ( 1 ) as claimed in  claim 20 ,
 wherein the steam pipe ( 40 ) is connected to the treatment chamber ( 2 ) at a location situated higher than the tank ( 12 ).   
     
     
         22 . The dishwasher ( 1 ) as claimed in  claim 20 ,
 wherein the fresh water feed device has a boiler ( 22 ) connected to a fresh water supply pipe ( 30 ), for warming the final-rinse liquid to be pumped into the treatment chamber ( 2 ) during the fresh water final-rinse phase, the outlet of the boiler being connected to the suction side of the at least one final-rinse pump ( 14 ;  14   a ,  14   b ),   wherein the steam generator ( 39 ) is integrated in the boiler ( 22 ).   
     
     
         23 . The dishwasher ( 1 ) as claimed in  claim 20 ,
 wherein a sensor device ( 52 ) is also provided, for detecting the total moisture quantity absorbed by the dry material of the sorption unit ( 41 ), the program control device ( 101 ) being designed to preferably selectively automatically connect the steam generator ( 39 ) during the steam final-rinse phase if the moisture quantity detected with the sensor device ( 52 ) at the start of the steam final-rinse phase and absorbed by the dry material is less than a lower threshold value.   
     
     
         24 . The dishwasher ( 1 ) as claimed in  claim 13 ,
 wherein a sensor device ( 52 ) is also provided, for detecting the total moisture quantity absorbed by the dry material of the sorption unit ( 41 ), the program control device ( 101 ) being designed to terminate the steam final-rinse phase as soon as a previously defined quantity of moisture has been desorbed from the dry material.