Dishwashers having a heat exchanger

Abstract

A dishwashing machine comprising a tub that defines a wash space where dishes can be washed, a sump fluidly connected to the tub, a drain pump fluidly connecting the sump to a discharge pipe, a water tank fluidly connected to the sump though an on-off value and a softener, a heat exchanger located inside the water tank, and a diverter valve.

1 - 8 . (canceled) 
     
     
         9 . A dishwashing machine comprising:
 a tub that defines a wash space where dishes can be washed;   a sump fluidly connected to said tub;   a drain pump fluidly connected to the sump to discharge waste wash water at the end of a wash cycle;   a water tank configured to receive and store a predefined amount of fresh water from an external water supply, said water tank being fluidly connected to the sump through an on-off valve and a softener;   a heat exchanger arranged inside the water tank;   wherein said heat exchanger has an inlet fluidly connected with the drain pump and an outlet fluidly connected to the tub; and   wherein a diverter valve is arranged downstream of the drain pump and configured to selectively direct a flow of water coming from the drain pump to either the heat exchanger or an external discharge pipe.   
     
     
         10 . The dishwashing machine of  claim 9 , further comprising a closed-loop drying assembly having a water tank with an inlet and an outlet, and wherein the drain pump is also fluidly connected to said inlet to selectively supply water to the water tank, while said outlet is fluidly connected to the sump. 
     
     
         11 . The dishwashing machine of  claim 10 , wherein the drain pump is fluidly connected to the water tank through a first diverter valve and a second diverter valve arranged downstream of the first diverter valve and connected in series with it, said second diverter valve being fluidly connected to the inlet of the heat exchanger and to the inlet of the water tank of the closed-loop drying assembly. 
     
     
         12 . The dishwashing machine of  claim 10 , wherein an on-off valve is associated with the outlet of the water tank of the closed-loop drying assembly, said on-off valve being operable to selectively feed water from the water tank to the sump. 
     
     
         13 . A method to operate a dishwashing machine having a heat exchanger arranged inside a water tank configured to receive and store a predefined amount of fresh water from an external water supply, said method comprising the following steps:
 feeding fresh water stored in said water tank to a sump of the dishwashing machine via a softener;   heating the fresh water received in the sump at a desired wash temperature;   carrying out a wash cycle;   filing fresh water into the water tank;   making hot waste water collected in the sump at the end of the wash cycle to circulate through the heat exchanger; and   draining the waste water out of the dishwashing machine;   wherein a drain pump of the dishwashing machine is employed to make the hot waste water circulate through the heat exchanger.   
     
     
         14 . The method of  claim 13 , wherein a diverter valve arranged downstream of the drain pump is employed to selectively supply hot waste water to the heat exchanger. 
     
     
         15 . The method of  claim 13 , wherein the drain pump is also fluidly connected with a water tank of a closed-loop drying assembly of the dishwashing machine, and wherein after the wash cycle the drain pump is employed to supply fresh water to said water tank to cool a condenser of said closed-loop drying assembly. 
     
     
         16 . The method of  claim 15 , wherein an on-off valve is associated with an outlet of the water tank of the closed-loop drying assembly, and wherein said valve is operated to selectively feed the water supplied by the drain pump to the water tank to the sump. 
     
     
         17 . A dishwashing machine comprising:
 a tub defining a wash space where dishes can be washed;   a sump fluidly connected to the tub;   a drain pump fluidly connecting the sump to a discharge pipe;   a first water tank fluidly connected to the sump through a first on-off valve and a softener;   a heat exchanger located inside the first water tank, the heat exchanger having a heat exchanger inlet and a heat exchanger outlet fluidly connected to the tub; and   a first diverter valve selectively fluidly coupling the drain pump to the heat exchanger inlet or the external discharge pipe.   
     
     
         18 . The dishwashing machine of  claim 17  further comprising a closed-loop drying assembly having a second water tank with a second water tank inlet fluidly connected to the drain pump, and a second water tank outlet fluidly connected to the sump. 
     
     
         19 . The dishwashing machine of  claim 18  further comprising a condenser located inside the second water tank of the closed-loop drying. 
     
     
         20 . The dishwashing machine of  claim 18  further comprising a second diverter valve, downstream of the first diverter valve, selectively fluidly coupling the drain pump to the heat exchanger inlet or the second water tank inlet. 
     
     
         21 . The dishwashing machine of  claim 20  wherein the second diverter valve is connected in series with the first diverter valve. 
     
     
         22 . The dishwashing machine of  claim 18  wherein the second water tank outlet is fluidly connected to the sump through a second on-off valve. 
     
     
         23 . A method of operating a dishwashing machine having a heat exchanger arranged inside a water tank configured to receive and store a predefined amount of fresh water from an external water supply, the method comprising:
 feeding fresh water stored in the water tank to a sump of the dishwashing machine via a softener;   heating the fresh water received in the sump to a desired wash temperature;   carrying out a wash cycle;   collecting hot waste water in the sump at an end of the wash cycle;   circulating the hot waste water with a drain pump through the heat exchanger; and   draining the waste water out of the dishwashing machine.   
     
     
         24 . The method of  claim 23  further comprising selectively supplying the hot waste water to the heat exchanger via a first diverter valve downstream of the drain pump. 
     
     
         25 . The method of  claim 24  further comprising supplying fresh water with the drain pump to a second water tank having a condenser of a closed-loop drying assembly located therein. 
     
     
         26 . The method of  claim 25  further comprising selectively feeding the water supplied by the drain pump to the second water tank, to the sump via an on-off valve.