Transparent Ice Maker

Abstract

An apparatus and method for producing substantially clear ice in a variety of desired shapes. The apparatus and method in the described embodiments generally provide for an insulated ice mold containing one or more mold cells, each mold cell with an open top, open bottom, and insulated side walls, that is suspended over a liquid water reservoir surrounded and contained in an insulated container. The top surface of the water residing in each mold cell is exposed to freezing air. The insulated walls forming the sides of one or more mold cells act to ensure that each ice shape forms and grows from the top surface, down and towards the bottom of each mold cell. The liquid water reservoir, which contacts the bottom surface of the ice shape, remains in a liquid phase and serves as an impurity sink into which the impurities and gases contained in the freezing water are driven as ice forms downward in the mold cell. The liquid water reservoir acts to arrest ice growth below the bottom of the mold cell, while the water in the mold cells freezes into a solid above the ice-water interface.

I claim: 
     
         1 . An apparatus for producing substantially clear ice, comprising:
 an insulated ice mold including one or more cells with insulated sidewalls and each cell having an open top and an open bottom;   an insulated container having an open top providing for placement of the insulated ice mold into the insulated container wherein the insulated ice mold is positioned and suspended above a bottom of the insulated container forming a liquid reservoir contained by sidewalls and the bottom of the insulated container below the ice mold.   
     
     
         2 . The apparatus of  claim 1 , wherein the ice mold is substantially impermeable to liquid. 
     
     
         3 . The apparatus of  claim 1 , wherein the insulated container is substantially impermeable to liquid. 
     
     
         4 . The apparatus of  claim 1 , wherein the ice mold and sidewalls are formed from a thermally insulating material. 
     
     
         5 . The apparatus of  claim 1 , wherein the one or more cells may be of any geometric shape. 
     
     
         6 . The apparatus of  claim 1 , wherein the ice mold is formed from a material selected from the group consisting of silicone, plastic, thermoplastic, polyethylene, polypropylene, polyurethane foam, beaded polystyrene foam, expanded polystyrene foam or low thermal conductivity material. 
     
     
         7 . A method for producing substantially clear ice, comprising:
 providing an ice mold having one or more cells and each cell having an open top and an open bottom;   providing an insulated container having an open top for placement of the ice mold therein, a bottom of the insulated container forming a liquid reservoir below the ice mold;   filling the one or more cells and the liquid reservoir with liquid;   directionally freezing the liquid from a top surface of the one or more cells to the bottom of the one or more cells to form one or more ice shapes; and,   reducing a rate of freezing near an interface between the one or more ice shapes and the liquid reservoir.   
     
     
         8 . The method of  claim 7 , further comprising:
 drawing impurities from the liquid contained in the one more cells to the liquid reservoir during formation of the one or more ice shapes.   
     
     
         9 . The method of  claim 7 , further comprising:
 extracting the one more ice shapes from the one or more cells.   
     
     
         10 . The method of  claim 7 , further comprising:
 extracting the one more ice shapes from the one or more cells before freezing of the liquid reservoir.