Refrigeration – Means producing shaped or modified congealed product – Heat absorber with product remover
Reexamination Certificate
2000-02-04
2001-05-01
Tapolcai, William E. (Department: 3744)
Refrigeration
Means producing shaped or modified congealed product
Heat absorber with product remover
Reexamination Certificate
active
06223550
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to freezers, and, more particularly, ice-making devices.
2. Description of the Related Art
The freezer portion of a refrigeration/freezer appliance often includes an ice cube maker which dispenses the ice cubes into a dispenser tray. A mold has a series of cavities, each of which is filled with water. The air surrounding the mold is cooled to a temperature below freezing so that each cavity forms an individual ice cube. As the water freezes, the ice cubes become bonded to the inner surfaces of the mold cavities.
In order to remove an ice cube from its mold cavity, it is first necessary to break the bond that forms during the freezing process between the ice cube and the inner surface of the mold cavity. In order to break the bond, it is known to heat the mold cavity, thereby melting the ice contacting the mold cavity on the outermost portion of the cube. The ice cube can then be scooped out or otherwise mechanically removed from the mold cavity and placed in the dispenser tray. A problem is that, since the mold cavity is heated and must be cooled down again, the time required to freeze the water is lengthened.
Another problem is that the heating of the mold increases the operational costs of the ice maker by consuming electrical power. Further, this heating must be offset with additional refrigeration in order to maintain a freezing ambient temperature, thereby consuming additional power. This is especially troublesome in view of government mandates which require freezers to increase their efficiency.
Yet another problem is that, since the mold cavity is heated, the water at the top, middle of the mold cavity freezes first and the freezing continues in outward directions. In this freezing process, the boundary between the ice and the water tends to push impurities to the outside of the cube. Thus, the impurities become highly visible on the outside of the cube and cause the cube to have an unappealing appearance. Also, the impurities tend to plate out or build up on the mold wall, thereby making ice cube removal more difficult.
A further problem is that vaporization of the water in the mold cavities causes frost to form on the walls of the freezer. More particularly, in a phenomenon termed “vapor flashing”, vaporization occurs during the melting of the bond between the ice and the mold cavity. Moreover, vaporization adds to the latent load or the water removal load of the refrigerator.
Yet another problem is that the ice cube must be substantially completely frozen before it is capable of withstanding the stresses imparted by the melting and removal processes. This limits the throughput capacity of the ice maker.
What is needed in the art is an ice maker which does not require heat in order to remove ice cubes from their cavities, has an increased throughput capacity, allows less evaporation of water within the freezer, eases the separation of the ice cubes from the auger and does not push impurities to the outer surfaces of the ice cubes.
SUMMARY OF THE INVENTION
The present invention provides an ice maker which, without heat, mechanically breaks the bond between the ice cubes and the mold cavities before the water is completely frozen. This method of breaking the bond increases throughput, conserves energy and allows the ice cubes to freeze on the outside first and continue freezing in an inward direction. By eliminating the melting procedure, the ice maker substantially reduces vaporization of water within the freezer, which is further reduced by sealing the water in the mold cavities from the ambient air.
The invention comprises, in one form thereof, an ice making apparatus including a mold having a cavity with a bottom surface. The mold cavity is configured for containing water therein for freezing into ice. An auger extends substantially vertically through the mold cavity. The auger is configured for rotating to thereby push the ice out of the mold cavity. The auger includes a rotatable surface at least partially defining the bottom surface of the mold cavity. The rotatable surface includes at least one ramp configured for lifting the ice off of the bottom surface of the mold cavity.
The invention comprises, in yet another embodiment thereof, an ice maker which includes a mold and an auger. The mold has at least one cavity with a bottom surface, and the at least one mold cavity is configured for containing water therein for freezing into ice. The auger includes a shaft having a longitudinal axis and having at least one flight attached thereto, the shaft including a top end and a base end with the base end being rotatably mounted in the bottom surface of the at least one mold cavity. The shaft extends substantially vertically through said at least one mold cavity and is configured to rotate and thereby push the ice out of said at least one mold cavity. The shaft and/or at least one flight has a radius that decreases relative to the longitudinal axis in a direction heading from the base end to the top end of the shaft and thereby has a radially inward taper in that direction.
An advantage of the present invention is that heat is not needed in order to break the bond between the ice cubes and their mold cavities, thereby conserving energy and reducing operational costs.
Another advantage is that, since the mold cavities are not heated, and since the ice cubes are not completely frozen before being removed from their cavities, the time spent freezing the water in the cavities is reduced, and the throughput rate is increased.
Yet another advantage is that, since the mold cavities are not heated, the water freezes from the outside in, thereby pushing impurities to the inside of the cube, where they are less conspicuous and do not plate out on the mold surface.
A further advantage is that, since the step of melting the outer surface of the ice is eliminated, and since the water is sealed from ambient air while freezing, vaporization of the water is greatly reduced, resulting in less frost on the wall of the freezer and less water that the refrigerator must remove.
A still further advantage is that the provision of at least one inward taper allows an ice cube to automatically become separated from at least a portion of the auger upon movement of the ice cube in an output direction. Even though the ice cube has an inward taper to match that of the auger, the inner diameter of the ice cube at a given location therein has its own specific value. Meanwhile, the diameter of at least a portion of the auger adjacent to that given location, the diameter of the shaft and/or the outer diameter of the at least one flight, continually decreases relative to the inner diameter of that given location as the ice cube is moved in the output direction. Consequently, since the contact area per unit length between the auger and an ice cube decreases as the ice cube moves along the auger, the friction per unit length therebetween also decreases.
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DeWitt Donald E.
Marsh John K.
Tchougounov Andrei
Group Dekko Services, LLC
Tapolcai William E.
Taylor & Aust P.C.
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