Ice maker circuit

Abstract

A refrigeration system for freezing fluid in a tray during a first operating mode and defrosting the ice during a second operating mode to facilitate the removal of the ice from the tray. In the first operating mode, refrigerant circulates through a circuit in a first direction and, in the second mode, the flow of refrigerant is reversed in a portion of the circuit. In the first operating mode, cool refrigerant exits an expansion device in the circuit and enters into the evaporator to freeze a fluid in the tray. In the second operating mode, a valve is operated to permit warm refrigerant exiting the compressor to enter into the evaporator to melt a portion of the ice reversing the flow of refrigerant therein. A second valve permits the reverse flow of refrigerant through the evaporator to return to the compressor inlet instead of passing through the expansion device and condenser.

1 . An ice maker, comprising: 
 an ice tray; and    a refrigeration system, comprising: 
 a compressor having an inlet and an outlet,  
 a condenser having an inlet and an outlet, said condenser inlet in fluid communication with said compressor outlet;  
 an expansion device having an inlet and an outlet, said expansion device inlet in fluid communication with said condenser outlet;  
 an evaporator, said evaporator having an inlet and an outlet, said evaporator in thermal communication with said ice tray, said inlet in fluid communication with said expansion device outlet;  
   said refrigeration system having a first operating mode in which refrigerant flows in a first direction from said expansion device outlet, into said evaporator through said inlet and out of said evaporator through said outlet to said compressor inlet,    said refrigeration system having a second operating mode in which refrigerant flows through said evaporator in a direction opposite said first direction from said compressor outlet to said evaporator through said evaporator outlet, wherein refrigerant exiting said evaporator during said second operating mode is returned to said compressor inlet instead of passing through said expansion device and said condenser, and    a first valve arrangement operable to place said refrigeration system alternatively in said first operating mode and said second operating mode.    
   
   
       2 . The ice maker of  claim 1 , further comprising a second valve in fluid communication with said expansion device outlet and said evaporator inlet, said second valve operable to place each said evaporator inlet in fluid communication with said compressor inlet when said refrigeration system is in said second operating mode, wherein refrigerant flowing into said evaporator through said evaporator outlet will flow into said compressor inlet.  
   
   
       3 . The ice maker of  claim 2 , wherein said second valve is selected to maintain a predetermined pressure drop between said evaporator inlet and said compressor inlet when said refrigeration system is in said second operating mode.  
   
   
       4 . The ice maker of  claim 2 , wherein said second valve is a check valve.  
   
   
       5 . The ice maker of  claim 2 , wherein said second valve is a check valve having an adjustable cracking pressure.  
   
   
       6 . The ice maker of  claim 1 , further comprising a storage vessel in fluid communication with said compressor outlet, wherein refrigerant exiting said compressor may accumulate in said storage vessel during said first operating mode and provide a reservoir of refrigerant to flow into said evaporator to warm said ice tray when said refrigeration system is placed into said second operating mode, whereby warming said ice tray can melt at least a portion of ice within said ice tray to facilitate release of said ice from said ice tray.  
   
   
       7 . The ice maker of  claim 6 , wherein said second valve is selected to maintain a predetermined pressure drop between said evaporator inlet and said compressor inlet when said refrigeration system is in said second operating mode.  
   
   
       8 . The ice maker of  claim 1 , wherein said second valve is a check valve.  
   
   
       9 . An ice maker, comprising: 
 an ice tray; and    a refrigeration circuit, comprising: 
 a compressor having an inlet and an outlet,  
 a condenser having an inlet and an outlet, said condenser inlet in fluid communication with said compressor outlet;  
 an expansion device having an inlet and an outlet, said expansion device inlet in fluid communication with said condenser outlet; and  
 an evaporator having an inlet and an outlet, said evaporator outlet positioned vertically above said evaporator inlet, said evaporator in thermal communication with said ice tray, said evaporator inlet in fluid communication with said expansion device outlet,  
   wherein said refrigeration system has a first operating mode in which refrigerant flows from said expansion device outlet into said evaporator through said evaporator inlet up through said evaporator, and through said evaporator outlet into said compressor inlet, and    wherein said refrigeration system has a second operating mode in which refrigerant flows from said compressor outlet into said evaporator through said evaporator outlet, downward through said evaporator, and out of said evaporator through said evaporator inlet,    whereby the flow of refrigerant during said second operating mode from said evaporator outlet downward to said evaporator inlet facilitates the release of ice within said ice tray by first melting ice at an upper portion of said ice tray and then flowing downwardly.    
   
   
       10 . The ice maker of  claim 9 , further comprising a storage vessel in fluid communication with said compressor outlet, wherein refrigerant exiting said compressor outlet may accumulate in said storage vessel during said first operating mode and provide a reservoir of refrigerant to flow into said evaporator to warm said ice tray when said refrigeration system is placed into said second operating mode.  
   
   
       11 . The ice maker of  claim 9 , further comprising a check valve in fluid communication with said expansion device outlet and said evaporator inlet to place said evaporator inlet in fluid communication with said compressor inlet when said refrigeration system is in said second operating mode, wherein refrigerant flowing into said evaporator through said evaporator outlet may flow into said compressor inlet.  
   
   
       12 . An ice maker, comprising: 
 an ice tray; and    a refrigeration circuit, comprising: 
 a compressor having an inlet and an outlet,  
 a storage vessel having an inlet and an outlet, said storage vessel inlet in fluid communication with said compressor outlet;  
 a condenser having an inlet in communication with the storage vessel outlet and an outlet,  
 an expansion device having an inlet and an outlet, said expansion device inlet in fluid communication with said condenser outlet;  
 an evaporator having an inlet and an outlet, said evaporator in thermal communication with said ice tray, said evaporator inlet in fluid communication with said expansion device outlet,  
   wherein said refrigeration system has a first operating mode in which warm refrigerant is stored within said storage vessel and the storage vessel outlet is out of fluid communication with the evaporator outlet and a second operating mode in which said storage vessel outlet is in fluid communication with said evaporator outlet and warm refrigerant stored within said storage vessel is released into said evaporator through its outlet to warm said ice tray; and    a valve arrangement in fluid communication with said evaporator outlet and said compressor outlet to place said refrigeration system in said first operating mode and said second operating mode.    
   
   
       13 . The ice maker of  claim 12 , wherein said outlet of said evaporator is positioned vertically above said evaporator inlet, wherein during said first operating mode refrigerant flows from said expansion device outlet into said evaporator through said evaporator inlet, up through said evaporator, and into said compressor inlet through said evaporator outlet, wherein during said second operating mode refrigerant flows from said storage vessel into said evaporator through said outlet, downward through said evaporator, and out of said evaporator through said evaporator inlet.  
   
   
       14 . The ice maker of  claim 13 , wherein said evaporator is mounted to said ice tray, and wherein the downward flow of refrigerant during said second operating mode facilitates the release of ice within said ice tray, as ice melted at an upper portion of said ice tray flows downwardly to release ice at the bottom of said ice tray.  
   
   
       15 . The ice maker of  claim 12 , wherein said second valve is selected to maintain a predetermined pressure drop between said evaporator inlet and said compressor inlet when said refrigeration system is in said second operating mode.