In accordance with the principals of the present invention, an ice
machine, tray, and process for producing high-quality, substantially
clear ice is provided. A
heat exchanger in the ice
machine removes energy from liquid, cooling the liquid from
room temperature to freezing temperature, then overcomes the heat of fusion to form ice. The tray containing a liquid is received in a freezing /
mixing chamber. The tray includes an
energy transfer surface in
thermal contact with the
heat exchanger to define a liquid / ice boundary layer. The tray further includes at least one freezing cavity having geometry defining surfaces to form the geometry of the ice. An egress area is defined in the tray above the geometry defining surfaces. A mixing mechanism is provided in operative communication with the liquid to create a velocity profile at the liquid / ice boundary layer to create a directional freezing process starting from the
energy transfer surface of the tray in
thermal contact with the
heat exchanger and growing through the freezing cavity up to the egress area. The velocity profile at liquid / ice boundary enables impurities to be washed away during the freezing process, deterring impurities from getting entrapped in the ice. Impurities in the liquid are thereby washed away and concentrate in a
pool away from the ice, ultimately in the egress area of the tray to be purged. In addition, in embodiments sensors can be provided to provide various functions selected from the group consisting of, for example, determining ice creation status, determining freezing height, varying ice creation, determining tray presence, detecting freezing /
mixing chamber door position, determining liquid level, and combinations thereof.