Thermally conductive ice-forming surfaces incorporating short-duration electro-thermal deicing

Abstract

An ice making machine comprising: a thermally conductive plastic or aluminum evaporator assembly comprising an array of ice forming surfaces; a water supply, a refrigerant supply and an electrical energy source; and a controller that during a freeze mode operates the water supply and the refrigerant supply to form ice on the ice forming surfaces and during a harvest mode operates the electrical energy source to apply electrical resistance energy (e.g., pulsed energy) to the evaporator assembly to melt an interfacial layer of the ice such that it is freed from the surfaces. Alternatively, the thermally conductive plastic or aluminum evaporator can include freezing tubes with resistance energy deicing (e.g., pulsed energy) or shell and tube type evaporators with pulsed energy deicing.

1 . An ice making machine comprising: 
 a thermally conductive plastic evaporator assembly comprising an array of ice forming surfaces;    a water supply, a refrigerant supply and an electrical energy source; and    a controller that during a freeze mode operates said water supply and said refrigerant supply to form ice on said ice forming surfaces and during a harvest mode operates said electrical energy source to apply electrical resistance energy to said evaporator assembly to melt an interfacial layer of said ice such that it is freed from said surfaces.    
   
   
       2 . The ice making machine of  claim 1 , wherein said evaporator assembly comprises a thermally conductive plastic base portion and a heater, wherein said heater is affixed to a surface of said thermally conductive plastic base portion, such that said heater is disposed between said ice and said base portion.  
   
   
       3 . The ice making machine of  claim 2 , wherein said heater comprises a flexible membrane and an electrical trace disposed on said flexible membrane.  
   
   
       4 . The ice making machine of  claim 2 , wherein said thermally conductive plastic base portion and said heater form an ice cell which is capable of forming ice shapes.  
   
   
       5 . The ice making machine of  claim 2 , wherein said heater is affixed to said thermally conductive plastic base portion by at least one selected from the group consisting of: adhesive, solvent bonding, ultrasonic bonding, and heat fusing.  
   
   
       6 . The ice making machine of  claim 1 , wherein said electrical resistance energy is electrical pulse energy.  
   
   
       7 . A method of making ice with an ice making machine that comprises a thermally conductive plastic evaporator assembly comprising an array of ice forming surfaces, a water supply, a refrigerant supply and an electrical energy source, said method comprising: 
 during a freeze mode operating said water supply and said refrigerant supply to form ice on said ice forming surfaces; and    during a harvest mode operating said electrical energy source to apply electrical resistance energy to said evaporator assembly to melt an interfacial layer of said ice such that it is freed from said surfaces.    
   
   
       8 . The method of  claim 7 , wherein said evaporator assembly comprises a thermally conductive plastic base portion and a heater, wherein said heater is affixed to a surface of said thermally conductive plastic base portion, such that said heater is disposed between said ice and said base portion.  
   
   
       9 . The method of  claim 8 , wherein said heater comprises a flexible membrane and an electrical trace disposed on said flexible membrane.  
   
   
       10 . The method of  claim 8 , wherein said thermally conductive plastic base portion and said heater form an ice cell which is capable of forming ice shapes.  
   
   
       11 . The method of  claim 8 , wherein said heater is affixed to said thermally conductive plastic base portion by at least one selected from the group consisting of: adhesive, solvent bonding, ultrasonic bonding, and heat fusing.  
   
   
       12 . The method of  claim 7 , wherein said electrical resistance energy is electrical pulse energy.  
   
   
       13 . An evaporator assembly for forming ice, said assembly comprising: a thermally conductive plastic base portion and an electrical resistance heater, wherein said heater is affixed to a surface of said thermally conductive plastic base portion, such that said heater is disposed between said ice and said base portion.  
   
   
       14 . The evaporator assembly according to  claim 13 , wherein said heater comprises a flexible membrane and an electrical trace disposed on said flexible membrane.  
   
   
       15 . The evaporator assembly according to  claim 14 , wherein said thermally conductive plastic base portion and said heater form an ice cell which is capable of forming ice shapes.  
   
   
       16 . The evaporator assembly according to  claim 13 , wherein said heater is affixed to said thermally conductive plastic base portion by at least one selected from the group consisting of: adhesive, solvent bonding, ultrasonic bonding, and heat fusing.  
   
   
       17 . The evaporator assembly according to  claim 13 , wherein said electrical resistance heater is an electrical pulse heater.  
   
   
       18 . An ice making machine comprising: 
 an evaporator assembly comprising at least one freezing tube and at least two thermally conductive plastic or metal evaporator plates, wherein said freezing tube is disposed between oppositely disposed evaporator plates;    at least one refrigerant conduit disposed within said thermally conductive plastic or metal evaporator plates;    a water supply in communication with an inlet port of said freezing tube;    a refrigerant supply in communication with said refrigerant conduit;    an electrical energy source in communication with said freezing tube; and    a controller that during a freeze mode operates said water supply and said refrigerant supply to form ice on an interior surface of said freezing tube and during a harvest mode operates said electrical energy source to apply electrical resistance energy to said freezing tube or to a heater disposed about said freezing tube to melt an interfacial layer of said ice formed on said interior surface of said freezing tube such that it is freed from said interior surface.    
   
   
       19 . The ice making machine according to  claim 18 , wherein said evaporator plate comprises at least first and second thermal transfer nodes which are spaced apart from one another and in thermal contact with an outer surface said freezing tube, thereby forming ice on said interior surface of said freezing tube at a location defined by contacting of said thermal transfer nodes and said freezing tube.  
   
   
       20 . The ice making machine according to  claim 18 , further comprising an electrical insulation layer disposed about the exterior surface of said freezing tube, such that ice is not formed on said interior surface of said freezing tube at a location where said thermal transfer nodes are not in direct contact with said freezing tube.  
   
   
       21 . The ice making machine according to  claim 18 , wherein said electrical resistance energy is electrical pulse energy.  
   
   
       22 . A method of making ice with an ice making machine that comprises an evaporator assembly comprising at least one freezing tube and at least two thermally conductive plastic or metal evaporator plates, wherein said freezing tube is disposed between oppositely disposed evaporator plates, a water supply, a refrigerant supply and an electrical energy source, said method comprising: 
 during a freeze mode operating said water supply and said refrigerant supply to form ice on an interior surface of said freezing tube; and    during a harvest mode operating said electrical energy source to apply electrical resistance energy to said freezing tube to melt an interfacial layer of said ice such that it is freed from said interior surface of said freezing tube.    
   
   
       23 . The method according to  claim 22 , wherein said evaporator plate comprises at least first and second thermal transfer nodes which are spaced apart from one another and in thermal contact with an outer surface said freezing tube, thereby forming ice on said interior surface of said freezing tube at a location defined by contacting of said thermal transfer nodes and said freezing tube.  
   
   
       24 . The method according to  claim 22 , further comprising an electrical insulation layer disposed about the exterior surface of said freezing tube, such that ice is not formed on said interior surface of said freezing tube at a location where said thermal transfer nodes are not in direct contact with said freezing tube.  
   
   
       25 . The method according to  claim 22 , wherein said electrical resistance energy is electrical pulse energy.  
   
   
       26 . An evaporator assembly for forming ice, said assembly comprising: 
 at least one freezing tube;    at least two thermally conductive plastic or metal evaporator plates, wherein said freezing tube is disposed between oppositely disposed evaporator plates;    a refrigerant conduit disposed substantially within said evaporator plate; and    an energy source connected to or disposed about said freezing tube for applying electrical resistance energy to said freezing tube or to a heater disposed about said freezing tube, thereby melting an interfacial layer of said ice formed on said interior surface of said freezing tube such that it is freed from said interior surface.    
   
   
       27 . The evaporator assembly according to  claim 26 , wherein said heater comprises a flexible membrane and an electrical trace disposed on said flexible membrane.  
   
   
       28 . The evaporator assembly according to  claim 26 , wherein said electrical resistance energy is electrical pulse energy.  
   
   
       29 . An ice making machine comprising: 
 an evaporator assembly comprising at least one freezing tube and at least two thermally conductive plastic or metal evaporator segments, wherein said freezing tube is disposed between oppositely disposed evaporator segments;    at least one refrigerant conduit disposed substantially perpendicularly through said thermally conductive plastic or metal evaporator segments;    a water supply in communication with an inlet port of said freezing tube;    a refrigerant supply in communication with said refrigerant conduit;    an electrical energy source in communication with said freezing tube; and    a controller that during a freeze mode operates said water supply and said refrigerant supply to form ice on an interior surface of said freezing tube and during a harvest mode operates said electrical energy source to apply electrical resistance energy to said freezing tube or to a heater disposed about said freezing tube to melt an interfacial layer of said ice formed on said interior surface of said freezing tube such that it is freed from said interior surface.    
   
   
       30 . The ice making machine according to  claim 29 , wherein said evaporator segment comprises at least first and second thermal transfer nodes which are spaced apart from one another and in thermal contact with an outer surface said freezing tube, thereby forming ice on said interior surface of said freezing tube at a location defined by contacting of said thermal transfer nodes and said freezing tube.  
   
   
       31 . The ice making machine according to  claim 29 , further comprising an electrical insulation layer disposed about the exterior surface of said freezing tube, such that ice is not formed on said interior surface of said freezing tube at a location where said thermal transfer nodes are not in direct contact with said freezing tube.  
   
   
       32 . The ice making machine according to  claim 29 , wherein said electrical resistance energy is electrical pulse energy.  
   
   
       33 . A method of making ice with an ice making machine that comprises an evaporator assembly comprising at least one freezing tube and at least two thermally conductive plastic or metal evaporator segments, wherein said freezing tube is disposed between oppositely disposed evaporator segments, a water supply, a refrigerant supply and an electrical energy source, said method comprising: 
 during a freeze mode operating said water supply and said refrigerant supply to form ice on an interior surface of said freezing tube; and    during a harvest mode operating said electrical energy source to apply electrical resistance energy to said freezing tube to melt an interfacial layer of said ice such that it is freed from said interior surface of said freezing tube.    
   
   
       34 . The method according to  claim 33 , wherein said evaporator plate comprises at least first and second thermal transfer nodes which are spaced apart from one another and in thermal contact with an outer surface said freezing tube, thereby forming ice on said interior surface of said freezing tube at a location defined by contacting of said thermal transfer nodes and said freezing tube.  
   
   
       35 . The method according to  claim 33 , further comprising an electrical insulation layer disposed about the exterior surface of said freezing tube, such that ice is not formed on said interior surface of said freezing tube at a location where said thermal transfer nodes are not in direct contact with said freezing tube.  
   
   
       36 . The method according to  claim 33 , wherein said electrical resistance energy is electrical pulse energy.  
   
   
       37 . An evaporator assembly for forming ice, said assembly comprising: 
 at least one freezing tube;    at least two thermally conductive plastic or metal evaporator segments, wherein said freezing tube is disposed between oppositely disposed evaporator segments;    a refrigerant conduit disposed substantially perpendicular to said evaporator segments; and    an energy source connected to or disposed about said freezing tube for applying electrical resistance energy to said freezing tube or to a heater disposed about said freezing tube, thereby melting an interfacial layer of said ice formed on said interior surface of said freezing tube such that it is freed from said interior surface.    
   
   
       38 . The evaporator assembly according to  claim 37 , wherein said heater comprises a flexible membrane and an electrical trace disposed on said flexible membrane.  
   
   
       39 . The evaporator assembly according to  claim 37 , wherein said electrical resistance energy is electrical pulse energy.  
   
   
       40 . An ice making machine comprising: 
 an evaporator assembly comprising a freezing tube, a shell disposed about said freezing tube, a plurality of insulating rings disposed at spaced apart longitudinal locations about the length of said freezing tubes, and refrigerant inlet and outlet ports disposed within a sidewall of said shell;    a water supply in communication with an inlet port of said freezing tube;    a refrigerant supply in communication with said refrigerant inlet port;    an electrical energy source in communication with said freezing tube; and    a controller that during a freeze mode operates said water supply and said refrigerant supply to form ice on an interior surface of said freezing tube and during a harvest mode operates said electrical energy source to apply electrical resistance energy to said freezing tube to melt an interfacial layer of said ice formed on said interior surface of said freezing tube such that it is freed from said interior surface.    
   
   
       41 . The ice making machine according to  claim 40 , wherein said electrical resistance energy is electrical pulse energy.  
   
   
       42 . A method of making ice with an ice making machine that comprises an evaporator assembly comprising a freezing tube, a shell disposed about said freezing tube, a plurality of insulating rings disposed at spaced apart longitudinal locations about the length of said freezing tube, and refrigerant inlet and outlet ports disposed within a sidewall of said shell, a water supply, a refrigerant supply connected to said refrigerant inlet port, and an electrical energy source, said method comprising: 
 during a freeze mode operating said water supply and said refrigerant supply to form ice on an interior surface of said freezing tube; and    during a harvest mode operating said electrical energy source to apply electrical resistance energy to said freezing tube to melt an interfacial layer of said ice such that it is freed from said interior surface of said freezing tube.    
   
   
       43 . The method according to  claim 42 , wherein said electrical resistance energy is electrical pulse energy.  
   
   
       44 . An evaporator assembly for forming ice, said assembly comprising: 
 a freezing tube;    a shell disposed about said freezing tube;    a plurality of insulating rings disposed at spaced apart longitudinal locations about the length of said freezing tube; and    refrigerant inlet and outlet ports disposed within a sidewall of said shell; and    an energy source connected to or disposed about said freezing tube for applying electrical resistance energy to said freezing tube, thereby melting an interfacial layer of said ice formed on said interior surface of said freezing tube such that it is freed from said interior surface.    
   
   
       45 . The evaporator assembly according to  claim 44 , wherein said electrical resistance energy is electrical pulse energy.  
   
   
       46 . An ice making machine comprising: 
 an evaporator assembly comprising a plurality of freezing tubes, a shell disposed about said freezing tubes, a plurality of insulating rings disposed at spaced apart longitudinal locations about the length of each said freezing tubes, and refrigerant inlet and outlet ports disposed within a sidewall of said shell;    a water supply in communication with an inlet port of each said freezing tube;    a refrigerant supply in communication with said refrigerant inlet port;    an electrical energy source in communication with each of said freezing tubes; and    a controller that during a freeze mode operates said water supply and said refrigerant supply to form ice on an interior surface of said freezing tubes and during a harvest mode operates said electrical energy source to apply electrical resistance energy to said freezing tubes to melt an interfacial layer of said ice formed on said interior surface of said freezing tube such that it is freed from said interior surface.    
   
   
       47 . The ice making machine according to  claim 46 , wherein said electrical resistance energy is electrical pulse energy.  
   
   
       48 . A method of making ice with an ice making machine that comprises an evaporator assembly comprising a plurality of freezing tubes, a shell disposed about said freezing tubes, a plurality of insulating rings disposed at spaced apart longitudinal locations about the length of each said freezing tubes, and refrigerant inlet and outlet ports disposed within a sidewall of said shell, a water supply, a refrigerant supply connected to said refrigerant inlet port, and an electrical energy source, said method comprising: 
 during a freeze mode operating said water supply and said refrigerant supply to form ice on an interior surface of said freezing tubes; and    during a harvest mode operating said electrical energy source to apply electrical resistance energy to said freezing tubes to melt an interfacial layer of said ice such that it is freed from said interior surface of said freezing tubes.    
   
   
       49 . The method according to  claim 48 , wherein said electrical resistance energy is electrical pulse energy.  
   
   
       50 . An evaporator assembly for forming ice, said assembly comprising: 
 a plurality of freezing tubes;    a shell disposed about said freezing tubes;    a plurality of insulating rings disposed at spaced apart longitudinal locations about the length of each said freezing tubes; and    refrigerant inlet and outlet ports disposed within a sidewall of said shell; and    an energy source connected to or disposed about said freezing tubes for applying electrical resistance energy to said freezing tubes, thereby melting an interfacial layer of said ice formed on said interior surface of said freezing tubes such that it is freed from said interior surface.    
   
   
       51 . The evaporator assembly according to  claim 50 , wherein said electrical resistance energy is electrical pulse energy.  
   
   
       52 . An ice making machine comprising: 
 an evaporator assembly comprising a helical tube, said helical tube comprising a freezing tube and at least one refrigerant conduit disposed about said freezing tube;    a water supply in communication with an inlet port of said freezing tube;    a refrigerant supply in communication with refrigerant conduit;    an electrical energy source in communication with said freezing tube; and    a controller that during a freeze mode operates said water supply and said refrigerant supply to form ice on an interior surface of said freezing tube and during a harvest mode operates said electrical energy source to apply electrical resistance energy to said freezing tube to melt an interfacial layer of said ice formed on said interior surface of said freezing tube such that it is freed from said interior surface.    
   
   
       53 . The ice making machine according to  claim 52 , wherein said electrical resistance energy is electrical pulse energy.  
   
   
       54 . A method of making ice with an ice making machine that comprises an evaporator assembly comprising a helical tube, said helical tube comprising a freezing tube and at least one refrigerant conduit disposed about said freezing tube, a water supply, a refrigerant supply connected to said refrigerant conduit, and an electrical energy source, said method comprising: 
 during a freeze mode operating said water supply and said refrigerant supply to form ice on an interior surface of said freezing tube; and    during a harvest mode operating said electrical energy source to apply electrical resistance energy to said freezing tube to melt an interfacial layer of said ice such that it is freed from said interior surface of said freezing tube.    
   
   
       55 . The method according to  claim 54 , wherein said electrical resistance energy is electrical pulse energy.  
   
   
       56 . An evaporator assembly for forming ice, said assembly comprising: 
 a helical tube, said helical tube comprising a freezing tube and at least one refrigerant conduit disposed about said freezing tube; and    an energy source connected to or disposed about said freezing tube for applying electrical resistance energy to said freezing tube, thereby melting an interfacial layer of said ice formed on said interior surface of said freezing tube such that it is freed from said interior surface.    
   
   
       57 . The evaporator assembly according to  claim 56 , wherein said electrical resistance energy is electrical pulse energy.