Water tray for clear ice maker

• US 3,952,539 A
• Filed: 11/18/1974
• Issued: 04/27/1976
• Est. Priority Date: 11/18/1974
• Status: Expired due to Term

• Current Assignee: General Motors Corporation (General Motors Company)
• Original Assignee: General Motors Corporation (General Motors Company)
• Inventors: Pugh, Cecil C., Hanson, Robert S.
• Primary Examiner(s): Wayner, William E.
• Assistant Examiner(s): Tapolcai, Jr., William E.
• Application Number:
  US05/524,974
• Time in Patent Office: 526 Days
• Field of Search: 62/351, 219/406, 219/407, 219/439, 219/385-387
• US Class Current: 62/351
• CPC Class Codes: F25C 1/04 by using stationary moulds
• CPC Class Codes: F25C 1/18 of a particular transparency or translucency, e.g. by injecting air
• CPC Class Codes: F25C 1/24 for refrigerators, e.g. freezing trays
• CPC Class Codes: F25C 2305/0221 rotating ice mould
• CPC Class Codes: F25C 5/08 by heating bodies in contact with the ice

Abstract

A clear ice maker has an improved stationary open-top water tray comprising a plastic frame with metal inserts in the tray side, end and bottom walls for containing a predetermined quantity of water. The tray receives a removable grid having a plurality of open-bottom, open-top ice mold cavities and flexible filler means between the cavities to displace substantially all of the water into the cavities when the grid is in the tray. The tray side and end metal inserts have heaters thereon which are activated prior to ice harvest to melt the ice bond between the grid and tray permitting release of the grid. The tray bottom wall metal insert has continuously energized heater means thereon and is formed to provide a raised area beneath each grid cavity, thereby preventing freezing through the bottom of the grid cavities.

Claims

1. A clear ice maker in a freezer comprising a tray having side and bottom walls adapted to contain a body of water, a grid in said tray having cavity-forming means for displacing the body of water contained by said walls into the cavity, fan means distributing sub-freezing air over the top planar surface of said body of water in said grid cavity for a sufficient period to initiate the freezing of clear ice in said grid cavity along the interface between said air and said top planar surface and to continue the freezing of clear ice downwardly in said grid cavity, and a bucket for storing said clear ice in said freezer and being removable from said freezer, heating means energizable to maintain said body of water in a liquid state adjacent said tray below the freezing clear ice, harvesting mechanism for removing said grid and clear ice from said tray before the freezing of clear ice downwardly in said grid cavity reaches the bottom wall of said tray and depositing said clear ice in said bucket, the improvement in said tray heating means comprising a composite tray having a plastic frame with side, end and bottom walls formed with window-like apertures therein, plate metal inserts positioned in said apertures, a first heater for said side and end wall inserts, a second heater for said bottom wall insert, said side and end wall metal inserts having a vertical dimension substantially coextensive with the clear ice cubes in said grid from their top planar surfaces to their lower surfaces, said first side wall heater operative to heat said side and end wall inserts, said second bottom wall heater operative to maintain said body of water below the freezing clear ice at an above freezing temperature, said bottom wall metal insert having a plurality of dome-like embossments formed in a grid-like pattern therein, whereby upon the grid being set down in said tray each grid cavity will be centered over an embossment such that heat will be transferred to the center of the clear ice cubes thereby forming a complementary concave bottom surface of the cubes preventing the cubes from forming peripheral flanges locking the cubes in said grid upon the inverting of said grid during the harvesting cycle of the ice maker.

2. A clear ice maker in a freezer comprising a tray having side and bottom walls adapted to contain a body of water, a grid in said tray having cavity-forming means for displacing the body of water contained by said walls into the cavity, fan means distributing sub-freezing air over the top planar surface of said body of water in said grid cavity for a sufficient period to initiate the freezing of clear ice in said grid cavity along the interface between said air and said top planar surface and to continue the freezing of clear ice downwardly in said grid cavity, and a bucket for storing said clear ice in said freezer and being removable from said freezer, heating means energizable to maintain said body of water in a liquid state adjacent said tray below the freezing clear ice, harvesting mechanism for removing said grid and clear ice from said tray before the freezing of clear ice downwardly in said grid cavity reaches the bottom wall of said tray and depositing said clear ice in said bucket, the improvement in said tray heating means comprising a composite tray having a polypropylene plastic frame with side, end and bottom walls formed with window-like apertures therein, aluminum metal insert plates positioned in said apertures, said plates having a thickness of about one and one-half times the thickness of said tray plastic frame, said plate peripheral edges formed with undercut grooves to provide a single lap-butt sealed joint with the edges of the tray apertures, a first resistance heater for said side and end wall insert, a second heater for said bottom wall insert, said side and end wall metal inserts having a vertical dimension substantially coextensive with the clear ice cubes in said grid from said top planar surface to the lower surface of the clear ice cubes, said bottom wall insert of a dimension to be coextensive with the bottom openings of said grid cavities, said first side wall heater operative to heat said side and end wall inserts, and said second bottom wall heater operative to maintain said body of water beneath the freezing clear ice at an above freezing temperature.