Clear ice making apparatus, clear ice making method and refrigerator

• US 6,935,124 B2
• Filed: 05/29/2003
• Issued: 08/30/2005
• Est. Priority Date: 05/30/2002
• Status: Expired due to Fees

• Current Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Ishii, Yuko, Tusima, Katutosi, Kida, Takumi, Hamada, Kazuyuki, Tatsui, Hiroshi, Takahashi, Yasuhito
• Primary Examiner(s): Tapolcai, William E.
• Application Number:
  US10/447,878
• Publication Number:
  US 20040025527A1
• Time in Patent Office: 824 Days
• Field of Search: 62/66, 62/68, 623/40, 623/56
• US Class Current: 62/74
• 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 2305/0221 rotating ice mould
• CPC Class Codes: F25C 2400/10 Refrigerator units
• CPC Class Codes: F25C 2400/14 Water supply
• CPC Class Codes: F25C 2600/04 Control means
• CPC Class Codes: F25C 5/08 by heating bodies in contact with the ice

Abstract

A clear ice making apparatus includes: a freezing space; a tray placed in the freezing space and having a lower temperature at a bottom part thereof than at an upper part thereof; and a water supply unit of supplying water to the tray from the top thereof, in which ice is made at an ice making rate of 5 μm/s or lower, a part of a liquid-phase section of water in the tray which part is in contact with atmosphere is frozen to complete the ice making, the liquid-phase section of water is not entirely supercooled before the ice making is completed, and the concentration of air in the liquid-phase section of water in the tray is equal to or lower than an excessive concentration of air.

Claims

1. A clear ice making apparatus having an ice making cycle defined as (a) supply water to a tray and (b) emptying the tray after water freezes in the tray, the apparatus comprising:

a freezing space;

a tray placed in said freezing space and having a lower temperature at a bottom part thereof than at an upper part thereof; and

water supply means of supplying water intermittently during the ice making cycle to said tray from a top of said tray, wherein;

the lower temperature at the bottom part of the tray is controlled such that an ice is made at an ice making rate of 5 μ

m/s or lower,

said water supply means supplies water intermittently to said tray so that a part of a liquid-phase section of water in said tray which part is in contact with atmosphere remains in a liquid phase until the ice making is completed, and

the liquid-phase section of water in said tray has a thickness equal to or less than a predetermined thickness.

2. The clear ice making apparatus according to claim 1, wherein said predetermined thickness is a thickness that allows substantially no air bubble to be generated.

3. The clear ice making apparatus according to claim 1 or 2, wherein said ice making rate is equal to or higher than 2 μ

m/s.

4. The clear ice making apparatus according to claim 1, wherein said water supply means starts a following supply of water before a surface of the water having already been supplied is frozen and repeats such supply of water until the ice being made attains a predetermined thickness, and

when the supply of water is stopped, the part of the liquid-phase section of water in said tray which part is in contact with atmosphere is lastly frozen.

5. The clear ice making apparatus according to claim 4, wherein the interval at which said water supply means supplies water is adapted to prevent the entire liquid-phase section of water in said tray from being supercooled.

6. The clear ice making apparatus according to any of claims 1, 2, and 4 wherein the temperature of a side surface of said tray is higher than that of the bottom surface thereof.

7. A clear ice making method of making a clear ice using a clear ice making apparatus, the clear ice making apparatus including a freezing space, a tray placed in said freezing space and having a lower temperature at a bottom part thereof than at an upper part thereof, and water supply means of supplying water intermittently to said tray, the method including the steps of:

a) controlling the lower temperature at the bottom part of the tray such that an ice is made at an ice making rate of 5 μ

m/s or lower, and

b) supplying water intermittently from the water supplying means such that the water is supplied intermittently during an ice making cycle, wherein the ice making cycle is defined as (i) supplying water to the tray and (ii) emptying the tray after water freezes in the tray;

a part of a liquid-phase section of water in said tray which part is in contact with atmosphere remains in a liquid phase until the ice making is completed, and

the liquid-phase section of water in said tray has a thickness equal to or less than a predetermined thickness.