Commercial dishwasher configured in the form of a box-type dishwasher and method of operating such a dishwasher

Abstract

A box-type dishwasher ( 1 ) has a treatment chamber ( 2 ), a wash system and a drying device ( 50 ). The drying device ( 50 ) has a sorption unit ( 51 ), having a reversibly dehydratable drying material ( 52 ), and at least one fan ( 53 ) for forming an air circuit, such that an air stream is directed through the sorption unit ( 51 ) and then supplied to the treatment chamber ( 2 ) again. The sorption unit ( 51 ) has a housing ( 54 ), which encloses at least some of the drying material ( 52 ) and has at least one outer wall ( 55 ). A device ( 56 ) is designed so that the air stream is divided up into a first air sub-stream ( 57 a ), at least some of which is directed through the drying material ( 52 ), and a second air sub-stream ( 57 b ), which is not directed through the drying material ( 52 ) and is used for thermally insulating or cooling the sorption unit ( 51 ).

1 . Commercial dishwasher ( 1 ) which is configured in the form of a box-type dishwasher, wherein the dishwasher ( 1 ) has the following:
 a treatment chamber ( 2 ), into which, and from which, washware can be inserted, and removed, preferably manually; and   a wash system having a wash pump ( 13 ) and a wash-line system ( 16 ) for delivering wash liquid, during a wash phase, from a wash tank ( 12 ) of the dishwasher ( 1 ) and for spraying the wash liquid through wash nozzles ( 15   a ,  15   b ) in the treatment chamber,   characterized by   a drying device ( 50 ) for withdrawing moisture continuously, or as and when required, from drying air which circulates in the treatment chamber ( 2 ), in particular during a drying phase,   wherein the drying device ( 50 ) has at least one sorption unit ( 51 ), having a reversibly dehydratable drying material ( 52 ), and at least one fan ( 53 ) for forming an air circuit, as and when required, such that an air stream is directed through the sorption unit ( 51 ) and then supplied to the treatment chamber ( 2 ) again,   wherein the sorption unit ( 51 ) has a housing ( 54 ), which encloses at least some of the drying material ( 52 ) and has at least one outer wall ( 55 ), and   wherein a device ( 56 ) is provided for dividing up the air stream which is to be directed through the sorption unit ( 51 ), wherein the device ( 56 ) is designed so that the air stream which is to be directed through the sorption unit ( 51 ) is divided up into a first air sub-stream ( 57   a ), at least some of which is directed through the drying material ( 52 ), and a second air sub-stream ( 57   b ), which is not directed through the drying material ( 52 ) and is used for thermally insulating or cooling the sorption unit ( 51 ).   
     
     
         2 . Dishwasher ( 1 ) according to  claim 1 ,
 wherein the device ( 56 ) for dividing up the air stream which is to be directed through the sorption unit ( 51 ) is designed so that the air stream generated by the fan ( 53 ) is divided up into the first and the second air sub-streams ( 57   a ,  57   b ) such that at least some of the second air sub-stream ( 57   b ) is directed, at least in certain regions, along the outer wall ( 55 ) of the housing ( 54 ).   
     
     
         3 . Dishwasher ( 1 ) according to  claim 1 ,
 wherein the device ( 56 ) for dividing up the air stream which is to be directed through the sorption unit ( 51 ) is designed so that the air stream generated by the fan ( 53 ) is divided up into the first and the second air sub-streams ( 57   a ,  57   b ) such that the air of the first air sub-stream ( 57   a ), prior to being mixed with the air of the second air sub-stream ( 57   b ), is at a temperature between 150° C. and 300° C., preferably between 200° C. and 250° C. and even more preferably between 220° C. and 230° C., and that the air of the second air sub-stream ( 57   b ), prior to being mixed with the air of the first air sub-stream ( 57   a ), is at a temperature between 70° C. and 120° C. and preferably between 80° C. and 100° C.   
     
     
         4 . Dishwasher ( 1 ) according to  claim 1 ,
 wherein the device ( 56 ) for dividing up the air stream which is to be directed through the sorption unit ( 51 ) is designed so that at least 50%, and preferably at least 70%, of the air stream generated by the fan ( 53 ) is directed as first air sub-stream ( 57   a ) through the drying material ( 52 ).   
     
     
         5 . Dishwasher ( 1 ) according to  claim 1 ,
 wherein the housing ( 54 ) of the sorption unit ( 51 ) contains a mixing region ( 58 ) for mixing the first air sub-stream ( 57   a ) with the second air sub-stream ( 57   b ) once the first air sub-stream ( 57   a ) has passed by the drying material ( 52 ).   
     
     
         6 . Dishwasher ( 1 ) according to  claim 1 ,
 wherein the device ( 56 ) for dividing up the air stream which is to be directed through the sorption unit ( 51 ) is designed so that at least some of the second air sub-stream ( 57   b ) is directed along the outer wall ( 55 ) of the housing ( 54 ) at least in certain regions in the interior of the housing ( 54 ).   
     
     
         7 . Dishwasher ( 1 ) according to  claim 1 ,
 wherein the device ( 56 ) for dividing up the air stream which is to be directed through the sorption unit ( 51 ) is designed so that at least some of the first air sub-stream ( 57   a ) is directed through the drying material ( 52 ) such that the first air sub-stream ( 57   a ), once it has passed by the drying material ( 52 ), runs, at least in certain regions, parallel to the second air sub-stream ( 57   b ).   
     
     
         8 . Dishwasher ( 1 ) according to  claim 1 ,
 wherein an air-directing element ( 63 ), in particular an air-directing plate, is provided, at least in certain regions, in the housing ( 54 ) of the sorption unit ( 51 ) in order to guide the first and/or second air sub stream ( 57   a ,  57   b ) through the sorption unit ( 51 ).   
     
     
         9 . Dishwasher ( 1 ) according to  claim 8 ,
 wherein the air-directing element ( 63 ), which is configured in particular in the form of an air-directing plate, is designed, and arranged, at least in certain regions, in the housing ( 54 ) of the sorption unit ( 51 ), such that the first air sub-stream is separated from the second air sub-stream ( 57   b ) at least in certain regions.   
     
     
         10 . Dishwasher ( 1 ) according to  claim 9 ,
 wherein the air-directing element ( 63 ), which is configured in particular in the form of an air-directing plate, is designed to transfer thermal energy from the first air sub-stream ( 57   a ) to the second air sub-stream ( 57   b ).   
     
     
         11 . Dishwasher ( 1 ) according to  claim 8 ,
 wherein the air-directing element ( 63 ), which is configured in particular in the form of an air-directing plate, is arranged in the housing ( 54 ) of the sorption unit ( 51 ) such that a flow channel ( 64 ) is formed between the air-directing element ( 63 ) and the drying material ( 52 ), the first air sub-stream ( 57   a ) flowing through the flow channel at least in certain regions.   
     
     
         12 . Dishwasher ( 1 ) according to  claim 11 ,
 wherein the device ( 56 ) for dividing up the air stream which is to be directed through the sorption unit ( 51 ) has an air separator ( 61 ) with an inlet and a first and second outlet, wherein the inlet of the air separator ( 61 ) is flow-connected to the pressure side of the fan ( 53 ), and wherein the first air sub-stream ( 57   a ) is supplied to the sorption unit ( 51 ) via the first outlet of the air separator ( 61 ) and the second air sub-stream ( 57   b ) is supplied to the sorption unit ( 51 ) via the second outlet of the air separator ( 61 ).   
     
     
         13 . Dishwasher ( 1 ) according to  claim 12 ,
 wherein the second outlet of the air separator ( 61 ) is flow-connected to a flow channel ( 62 ) designed in the form of an air bypass, wherein the flow channel ( 62 ), which is designed in the form of an air bypass, is bounded, at least in certain regions, by the outer wall ( 55 ) of the housing ( 54 ) of the sorption unit ( 51 ).   
     
     
         14 . Dishwasher ( 1 ) according to  claim 13 ,
 wherein the flow channel ( 62 ), which is designed in the form of an air bypass, extends preferably over the width of the housing ( 54 ) of the sorption unit ( 51 ), and wherein the flow channel ( 62 ), which is designed in the form of an air bypass, has a height of 3 to 10 mm and preferably 4 to 6 mm.   
     
     
         15 . Dishwasher ( 1 ) according to  claim 13 , wherein the air-directing element ( 63 ), which is configured in particular in the form of an air-directing plate, bounds, at least in certain regions, the flow channel ( 62 ), which is designed in the form of an air bypass. 
     
     
         16 . Dishwasher ( 1 ) according to  claim 12 ,
 wherein the first outlet of the air separator ( 61 ) is flow-connected to a flow channel ( 65 ) bounded, at least in certain regions, by the drying material ( 52 ).   
     
     
         17 . Dishwasher ( 1 ) according to  claim 16 ,
 wherein the effective flow cross section of the flow channel ( 65 ), which is bounded, at least in certain regions, by the drying material ( 52 ), decreases in the flow direction of the first air sub-stream ( 57   a ).   
     
     
         18 . Dishwasher ( 1 ) according to  claim 16 ,
 wherein an air-directing element ( 66 ) is provided, this being assigned to the first air sub-stream ( 57   a ) and additionally bounding the flow channel ( 65 ), which is bounded, at least in certain regions, by the drying material ( 52 ).   
     
     
         19 . Dishwasher ( 1 ) according to  claim 12 , wherein the first and second outlets of the air separator ( 61 ) and the air-directing element ( 63 ), which is configured, in particular, in the form of an air-directing plate, are designed such that it is only once it has passed by the drying material ( 52 ) that the first air sub-stream ( 57   a ) flows through the flow channel ( 64 ), which is formed between the air-directing element ( 63 ) and the drying material ( 52 ). 
     
     
         20 . Dishwasher ( 1 ) according to  claim 1 ,
 wherein the quantity of air circulated by the at least one fan ( 53 ) per unit of time is around 20 to 120 m 3 /h, preferably around 40 to 100 m 3 /h, and even more preferably around 80 to 100 m 3 /h.   
     
     
         21 . Dishwasher ( 1 ) according to  claim 1 ,
 wherein the treatment chamber ( 2 ) has at least one intake opening ( 60 ), which is flow-connected to the suction side of the fan ( 53 ) in order to take in air from the treatment chamber ( 2 ), and wherein the treatment chamber ( 2 ) has at least one exhaust opening ( 59 ), via which the first and second air sub-streams ( 57   a ,  57   b ) are supplied, preferably jointly, to the treatment chamber ( 2 ) again once they have passed by the sorption unit ( 51 ).   
     
     
         22 . Dishwasher ( 1 ) according to  claim 21 ,
 wherein the at least one intake opening ( 60 ) and the at least one exhaust opening ( 59 ) are spaced apart from one another and open out into the treatment chamber ( 2 ) preferably in an upper region of the treatment chamber ( 2 ).   
     
     
         23 . Dishwasher ( 1 ) according to  claim 1 ,
 wherein the reversibly dehydratable drying material ( 52 ) has 0.3 to 3.0 kg, and preferably 1.0 to 1.5 kg, of zeolite-containing material preferably in the form of granules with a particle diameter of 0.5 to 10.0 mm.   
     
     
         24 . Dishwasher ( 1 ) according to  claim 1 ,
 wherein the drying device ( 50 ) also has a heating unit for heating the reversibly dehydratable drying material ( 52 ) as and when required, wherein the heating unit has a multiplicity of heating elements, which are arranged preferably at uniform intervals within the reversibly dehydratable drying material ( 52 ).   
     
     
         25 . Method of operating a dishwasher ( 1 ) which is designed in the form of a box-type dishwasher and has a treatment chamber ( 2 ) for accommodating washware which is to be cleaned, wherein the method has the following steps:
 i) during an absorption phase, air is directed out of the treatment chamber ( 2 ) through a sorption unit ( 51 ), having a reversibly dehydratable drying material ( 52 ), such that the drying material ( 52 ) absorbs moisture from the air stream, wherein the air is then supplied to the treatment chamber ( 2 ) again; and   ii) during a desorption phase, the drying material ( 52 ) of the sorption unit ( 51 ) is heated and, at the same time, air is directed out of the treatment chamber ( 2 ) through the sorption unit ( 51 ) such that moisture is desorbed from the drying material ( 52 ) and at least some of the thermal energy introduced into the drying material ( 52 ), and at least some of the moisture desorbed from the drying material ( 52 ), is discharged as water vapour from the sorption unit ( 51 ) with the aid of the air stream directed through the sorption unit ( 51 ),   wherein the air which is to be directed through the sorption unit ( 51 ) is divided up into a first air sub-stream, at least some of which is directed through the drying material ( 52 ), and into a second air sub-stream ( 57   b ), at least some of which is directed, at least in certain regions, along an outer wall ( 55 ) of the housing ( 54 ) of the sorption unit ( 51 ).   
     
     
         26 . (canceled)