Safe and efficient dish washing machine

Abstract

A dish washing machine comprising a fresh water reservoir for receiving fresh water configured to be heated, a first tank for receiving the initially heated fresh water from the fresh water reservoir and including a first heating system for heating the initially heated fresh water to form further heated fresh water, a second tank configured to receive the further heated fresh water and including a second heating system for heating the further heated fresh water to form further heated wash water, and a drain pipe for delivering the further heated wash water from the second tank through the fresh water reservoir and to a liquid outlet, with the drain pipe transferring heat from the further heated wash water to the fresh water in the fresh water reservoir to form the initially heated fresh water. The heating systems can comprise a positive temperature coefficient heating element.

What is claimed is: 
     
         1 . A dish washing machine comprising:
 a housing having an interior wash space for washing dishes;   a liquid inlet for adding fresh water to the dish washing machine;   a liquid outlet for removing dirty liquid from the dish washing machine;   a fresh water reservoir for receiving the fresh water therein from the liquid inlet, the fresh water in the fresh water reservoir being configured to be heated to form initially heated fresh water;   a first water tank for receiving the initially heated fresh water from the fresh water reservoir, the first water tank including a first heating system for heating the initially heated fresh water to form further heated fresh water;   first piping for delivering the further heated fresh water to at least one spray nozzle for spraying the further heated fresh water onto dishes positioned within the interior wash space;   a second water tank configured to receive the further heated fresh water from the interior wash space, the second water tank including a second heating system for heating the further heated fresh water to form further heated wash water;   second piping for delivering the further heated wash water to the at least one spray nozzle for spraying the further heated wash water into the interior wash space; and   a drain pipe for delivering the further heated wash water from the second water tank through the fresh water reservoir and to the liquid outlet, the drain pipe transferring heat from the further heated wash water to the fresh water in the fresh water reservoir to form the initially heated fresh water.   
     
     
         2 . The dish washing machine of  claim 1 , further including:
 a pump for pumping the initially heated fresh water from the fresh water reservoir to the first water tank and for pumping the further heated fresh water from the first water tank to the at least one spray nozzle.   
     
     
         3 . The dish washing machine of  claim 1 , wherein:
 the at least one spray nozzle is a plurality of spray nozzles located on a top rotating arm and a bottom rotating arm.   
     
     
         4 . The dish washing machine of  claim 1 , wherein:
 the drain pipe includes a horizontal portion within the fresh water reservoir and an elbow hot water waste retainer just outside of the fresh water reservoir, the elbow hot water waste retainer including a lower surface that is above the horizontal portion to allow the further heated wash water to pool in the horizontal portion.   
     
     
         5 . The dish washing machine of  claim 1 , further including:
 a first pump for pumping the initially heated fresh water from the fresh water reservoir to the first water tank and for pumping the further heated fresh water from the first water tank to the at least one spray nozzle; and   a second pump for pumping the further heated wash water from the second water tank to the at least one spray nozzle.   
     
     
         6 . The dish washing machine of  claim 1 , wherein:
 both the first heating system and the second heating system comprise a stainless steel shell with a positive temperature coefficient heating array located therein, the positive temperature coefficient heating array comprising a plurality of positive temperature coefficient heating elements, with a temperature sensor being connected to a heater cover, the temperature sensor measuring a temperature of the first heating system to maintain the temperature of the first heating system under a predetermined temperature.   
     
     
         7 . The dish washing machine of  claim 6 , wherein:
 the temperature sensor of the first heating system is not immersed in the initially heated fresh water.   
     
     
         8 . The dish washing machine of  claim 6 , wherein:
 the temperature sensor of the second heating system is not immersed in the further heated wash water.   
     
     
         9 . A dish washing machine comprising:
 a housing having an interior wash space for washing dishes and at least one spray nozzle for spraying liquid onto dishes positioned within the interior wash space;   a liquid tank for supplying liquid to the at least one spray nozzle;   the liquid tank including a heating system comprising a stainless steel shell with a positive temperature coefficient heating array located therein, the positive temperature coefficient heating array comprising a plurality of positive temperature coefficient heating elements, with a temperature sensor being connected to a heater cover, the temperature sensor measuring a temperature of the first heating system to maintain the temperature of the first heating system under a predetermined temperature;   the temperature sensor of the first heating system not being immersed in the liquid within the liquid tank.   
     
     
         10 . A method of washing dishes comprising:
 providing a housing having an interior wash space for receiving dishes;   adding fresh water to a dish washing machine;   feeding the fresh water to a fresh water reservoir;   heating the fresh water in the fresh water reservoir to form initially heated fresh water;   delivering the initially heated fresh water from the fresh water reservoir to a first water tank;   heating the initially heated fresh water in the first water tank with a first heating system to form further heated fresh water;   supplying the further heated fresh water to at least one spray nozzle;   spraying the further heated fresh water onto dishes positioned within the interior wash space;   delivering the further heated fresh water from the interior wash space to a second water tank;   heating the further heated fresh water in the second water tank with a second heating system to form further heated wash water;   delivering the further heated wash water to the at least one spray nozzle;   spraying the further heated wash water into the interior wash space; and   draining the further heated wash water through a drain pipe that passes through the fresh water reservoir and to a liquid outlet;   wherein heating the fresh water in the fresh water reservoir to form the initially heated fresh water comprises transferring heat from the further heated wash water to the fresh water in the fresh water reservoir.   
     
     
         11 . The method of  claim 10 , further including:
 pumping the initially heated fresh water from the fresh water reservoir to the first water tank and pumping the further heated fresh water from the first water tank to the at least one spray nozzle with a pump.   
     
     
         12 . The method of  claim 10 , wherein:
 the at least one spray nozzle is a plurality of spray nozzles located on a top rotating arm and a bottom rotating arm.   
     
     
         13 . The method of  claim 10 , wherein:
 the drain pipe includes a horizontal portion within the fresh water reservoir and an elbow hot water waste retainer just outside of the fresh water reservoir, the elbow hot water waste retainer including a lower surface that is above the horizontal portion to allow the further heated wash water to pool in the horizontal portion.   
     
     
         14 . The method of  claim 10 , further including:
 pumping the initially heated fresh water from the fresh water reservoir to the first water tank and pumping the further heated fresh water from the first water tank to the at least one spray nozzle with a first pump; and   pumping the further heated wash water from the second water tank to the at least one spray nozzle with a second pump.   
     
     
         15 . The method of  claim 10 , wherein:
 both the first heating system and the second heating system comprise a stainless steel shell with a positive temperature coefficient heating array located therein, the positive temperature coefficient heating array comprising a plurality of positive temperature coefficient heating elements, with a temperature sensor being connected to a heater cover, the temperature sensor measuring a temperature of the first heating system to maintain the temperature of the first heating system under a predetermined temperature.   
     
     
         16 . The method of  claim 15 , wherein:
 the temperature sensor of the first heating system is not immersed in the initially heated fresh water.   
     
     
         17 . The method of  claim 15 , wherein:
 the temperature sensor of the second heating system is not immersed in the further heated wash water.