Patent Grant
8459047
1. Field of the Invention
The present invention is directed generally to making ice, and more particularly, to a method and apparatus for making clear ice within a fresh-food compartment of a refrigeration appliance, optionally to be dispensed through a door provided to restrict access into said fresh-food compartment.
2. Description of Related Art
Traditionally, making ice includes filling each individual ice mold in an ice tray with water and placing the ice tray in a freezer compartment having an ambient temperature well below 32° F. Once the water is fully frozen, the ice trays are removed from the freezer and each individual cube ejected from its mold into a bin or placed into a fluid medium to be cooled. However, such a batch process of making ice cubes requires manually filling the ice trays each time ice is to be made. Further, the extremely cold temperatures within the freezer compartment cause the ice to freeze more rapidly than air and other gasses trapped within the water can escape, causing the gas to be trapped within the ice, which leads to the ice having an opaque appearance.
More recently, automated ice makers have been disposed within the freezer compartments of refrigeration appliances where the ambient temperature is again much colder than the freezing point of water. The need for manually filling the ice trays is eliminated by the automatic distribution of water into each of the individual ice molds of the ice tray. But again, the rate at which the ice is frozen due to the ambient temperature within the freezer compartment is too fast to allow the gas within the water to escape before it freezes, which causes the ice to have an opaque appearance.
To minimize the opacity of the ice, more gradual methods of freezing water have been developed. Such methods require the cyclical submergence of a freezing finger into each individual ice mold of the ice tray within a freezer compartment in which the ambient temperature is well below the temperature at which water freezes. As the freezing fingers are submerged and removed from the water in the mold for each cube, air bubbles at the surface of each freezing finger follow the finger and float upward and out of the water. With the air bubbles removed, the resulting ice exhibits less opacity. But such methods chill the temperature of the fingers to a temperature much lower than the temperature at which water freezes to expedite freezing. It is typical for conventional freezing methods and devices to require chilling of the fingers to a temperature of −22° C., which corresponds to a temperature of −7.6° F. Such cold finger temperatures again freeze the water in contact with the fingers too quickly to allow the air bubbles to escape, resulting in an opaque region in the center of each cube. Additionally, the ice so created is stored within the freezer compartment with its ambient temperature much lower than the freezing temperature of water, resulting in the formation of an opaque ice film on the exterior surfaces of the ice.
Newer designs of refrigeration appliances have also recently moved the freezer compartment from its conventional location vertically above or laterally to the side of a fresh food compartment. Such conventional locations allowed the ice formed in the freezer compartment to fall under the force of gravity into a dispenser unit that could be accessed externally of the refrigeration appliance. This way, ice could be obtained without having to open the door to the freezer compartment. But with the freezer compartment vertically beneath the fresh food compartment, ice can not fall under the force of gravity into an ice dispenser provided at an accessible location in the door of the refrigeration unit. Moreover, some refrigeration units include only a fresh food compartment, giving consumers the option to utilize a separate large-capacity, stand-alone freezer unit located at a remote location away from the kitchen.
Accordingly, there is a need in the art for a method and apparatus for making substantially-transparent ice that minimizes opacity of the ice resulting from a trapped gas.
According to one aspect, the present invention provides a method of making substantially-transparent ice within a fresh-food compartment of a refrigeration appliance. The method includes adjusting a temperature of an exposed surface of a plurality of fingers to which the ice is to freeze to a finger temperature that is less than or equal to about 32° F., and maintaining a temperature within the fresh-food compartment in which the fingers and a water tray are disposed to an ambient temperature that is greater than or equal to about 32° F. Water is introduced into the water tray disposed within the fresh-food compartment, and at least a portion of the fingers are repeatedly submerged in the water within the water tray and subsequently at least partially removed from the water during formation of the substantially-transparent ice.
According to another aspect, the present invention provides a refrigeration appliance including an ice maker for making substantially-transparent ice. The refrigeration appliance comprises a fresh food compartment in which a refrigeration temperature that is greater than 32° F. and less than 55° F. is maintained. A water tray is disposed within the fresh food compartment and exposed to an ambient environment of the fresh food compartment maintained at the refrigeration temperature. The water tray includes a bottom surface and an upwardly extending wall forming a reservoir for holding a volume of water, and a plurality of fingers are supported adjacent to the water tray to be at least partially submerged in water within the water tray. An evaporator is provided in thermal communication with the fingers for chilling an exposed surface of the fingers to a finger temperature that is less than 32° F. A controller controls a depth of water relative to the fingers to repeatedly submerge at least a portion of the fingers in the water and subsequently remove the fingers from the water to build substantially-transparent ice on an exposed surface of the fingers.
According to another aspect, the present invention provides a refrigeration appliance including an ice maker for making substantially-transparent ice. The refrigeration appliance comprises a fresh food compartment in which a refrigeration temperature greater than or equal to 32° F. and less than 55° F. is maintained. A water tray is disposed within the fresh food compartment and includes a bottom surface and an upwardly extending wall forming a reservoir for holding a volume of water. A plurality of fingers are supported within the fresh food compartment adjacent to the water tray to be at least partially submerged in water within the water tray. An evaporator in thermal communication with the fingers chills an exposed surface of the fingers to a finger temperature within a range of about 28° F. to about 32° F., and a second evaporator in thermal communication with the fresh food compartment maintains the refrigeration temperature therein. The second evaporator is operable independent of the evaporator in thermal communication with the fingers, and a compressor introduces a refrigerant to both the evaporator in thermal communication with the fingers and the second evaporator. A defroster is provided in thermal communication to at least partially melt a portion of the ice in direct contact with the fingers for separating the ice from the fingers. During ice formation, a depth to which the fingers are submerged in the water within the water tray is repeatedly adjusted to form substantially-transparent ice.
The invention may take physical form in certain parts and arrangement of parts, embodiments of which will be described in detail in this specification and illustrated in the accompanying drawings which form a part hereof and wherein:
Certain terminology is used herein for convenience only and is not to be taken as a limitation on the present invention. Relative language used herein is best understood with reference to the drawings, in which like numerals are used to identify like or similar items. Further, in the drawings, certain features may be shown in somewhat schematic form.
An embodiment of a refrigeration appliance 10 including an ice maker 12 for making substantially-transparent ice in a fresh food compartment 14 is shown in
A water/ice dispenser 26 can optionally be exposed to an external environment of the refrigeration appliance 10 to dispense water, ice, or both water and ice without requiring access to an interior of the fresh food compartment 14 or the freezer compartment 16 through an open door 18, 20. For the embodiment shown in
The fresh food compartment 14 is also commonly referred to as a refrigerator, and has an ambient temperature therein maintained within a range of temperatures from about 32° F. to about 55° F., including all sub-ranges within said range. Thus, the ambient temperature within the fresh food compartment 14 is less than the room temperature of a typical kitchen, but greater than the temperature at which water freezes, which is about 32° F. at sea level. The freezer compartment 16, on the other hand, has an ambient temperature therein maintained at a temperature that is less than 30° F., and more appropriately within a range of temperatures from about −15° F. to about 15° F., including all sub-ranges within said range.
The arrangement shown in
A plurality of fingers 48 are also supported within the fresh food compartment 14 adjacent to the water tray 38 to be at least partially submerged in water within the water tray 38 when it is desired to make substantially-transparent ice. Each finger 48 can include a generally cylindrical metal housing suspended from a frame 50, which can also be formed from a metal or other suitable conductor of thermal energy. The frame 50 defines a generally cylindrical interior passage through which a refrigerant can travel to remove thermal energy from the frame 50, and accordingly, the fingers 48. The frame 50 and fingers 48 are in fluid communication with an ice maker refrigeration circuit 52, shown in, and discussed in detail with regard to
The refrigeration circuits for removing thermal energy from environments to be chilled will be described with reference to
The fresh food refrigeration circuit 56 includes a condenser 58 in which the refrigerant undergoes a state change by cooling from a high pressure, high temperature gas to a liquid with a temperature that is lower than the high-temperature gas. An embodiment of the condenser 58 includes a segment of metal tubing bent into a network of coils in thermal communication with fins to maximize the surface area for transferring thermal energy to an ambient environment of the condenser 58. As the refrigerant condenses it releases thermal energy, including latent heat of condensation due to the state change, that is discharged as heat into the ambient environment of the refrigeration appliance 10 through the condenser 58.
Once the refrigerant has condensed in the condenser 58, the liquid refrigerant remains at a relatively high pressure before entering an expansion valve 60, which can alternately be a capillary tube or other expansion conduit, which is in fluid communication with the condenser 58. The expansion valve 60 is a valve that meters the flow of high-pressure liquid refrigerant flowing from the condenser 58 to a low-pressure environment within fresh food compartment evaporator coils 64 discussed below. It also contributes to the pressure drop between the condenser 58 and fresh food compartment evaporator coils 64, substantially isolating those two environments from each other.
As the refrigerant flows through the expansion valve 60 it enters the fresh food compartment evaporator coils 64, which are provided with fins to maximize surface area for heat transfer and are disposed within the freezer compartment 16. Air chilled by the evaporator coils 64 is blown into the fresh-food compartment 14 through passages extending between the fresh-food and freezer compartments 14, 16 to remove thermal energy from the fresh-food compartment 14. The pressure of the refrigerant within the fresh food compartment evaporator coils 64 is lower than the pressure of the refrigerant in the condenser 58. Like the condenser 58, the fresh food compartment evaporator coils 64 can include a metallic tube, a section of which being bent into a network that maximizes the surface area available for heat transfer to take place. Experiencing such a change in pressure upon entering the fresh food compartment evaporator coils 64, the liquid refrigerant rapidly evaporates back into a substantially gaseous phase. In order for this to occur, however, the refrigerant must draw a significant amount of thermal energy, including the latent heat of vaporization, from an ambient environment of the evaporator coils 64. This ambient environment of the evaporator coils 64 in the present example is the freezer compartment 16 of the refrigeration appliance 10. Cold air from the freezer compartment 16 can selectively be blown into the fresh-food compartment by a fan or other air mover (not shown) to maintain the temperature in the fresh-food compartment within the desired range of acceptable temperatures. Blowing the chilled air into the fresh food compartment 14 causes the temperature within the fresh food compartment 14 to drop, thereby chilling that compartment to a temperature below about 55° F., but above the freezing temperature of water.
A compressor 66 is provided to the refrigeration appliance 10 in fluid communication with the fresh food compartment evaporator coils 64 for establishing a vacuum at an outlet of the fresh food compartment evaporator coils 64. This vacuum sucks the evaporated refrigerant from the fresh food compartment evaporator coils 64, thereby maintaining the low pressure downstream of the expansion valve 60 relative to upstream of the expansion valve 60 within the condenser 58. The compressor 66 compresses the gaseous refrigerant discharged from the fresh food compartment evaporator coils 64 to a pressure that is higher than the pressure of the refrigerant input to the compressor 66, which also causes the temperature of the refrigerant to increase. The high-pressure, high-temperature refrigerant is then again re-introduced to the condenser 58 and the cycle is repeated as necessary to maintain the temperature within the freezer compartment 16 and the fresh food compartment 14.
The ice maker refrigeration circuit 52 operates similar to the fresh food refrigeration circuit 56 in theory. High-pressure, high-temperature gaseous refrigerant from the compressor 66 is condensed within the condenser 58, which can optionally be the same condenser 58 shared with the fresh food refrigeration circuit 56, as shown in
The ice maker refrigeration circuit 52 also includes a pressure regulator 72 such as a rolling diaphragm air cylinder, electropneumatic transducer, and the like, downstream of the ice maker evaporator coils 74 but before (i.e., upstream of) the compressor 66 in the ice maker refrigeration circuit 52 to control the pressure therein, which in turn controls the finger temperature. References herein to “upstream” and “downstream” are best understood relative to the various components within the refrigeration circuits 52, 56. A component in the refrigeration circuits 52, 56 after the compressor 66 through which the refrigeration travels before reaching a subsequent component is said to be “upstream” of that subsequent component. For example, the ice maker expansion valve 68 is upstream of the pressure regulator 72 because when considering the compressor 66 as the beginning of the ice maker refrigeration circuit 52, the refrigerant flows through the ice maker expansion valve 68 before reaching the pressure regulator 72 under normal operating conditions.
The pressure regulator 72 is operable to selectively minimize the effect of the vacuum created at the input of the compressor 66, while operating, on the pressure at the outlet of the ice maker evaporator coils 74. The low-pressure intake line 78 leading into the compressor 66 can optionally be shared by the fresh food refrigeration circuit 56 and the ice maker refrigeration circuit 52 to return evaporated gaseous refrigerant from both refrigeration circuits 52, 56 to the compressor 66. As shown in
Once the substantially-transparent ice has formed on the fingers 48 as described in detail below, the ice must be removed in order to be easily extracted from the bin 34. The temperature of the exposed surface of the fingers 48 is temporarily elevated to a finger temperature above the freezing point of water, or above 32° F. This melts at least a portion of the ice in contact with the exposed surface of the fingers 48, allowing the ice to fall from the fingers 48 under the force of gravity into the bin 34, which is disposed vertically beneath the water tray 38. Any remaining water in the water tray 38 is drained, and the water tray 38 is pivoted about axis 46-46 when the ice is to be removed from the fingers 48 to allow the falling ice from the fingers 48 to reach the bin 34.
According to one embodiment, the exposed surface of the fingers 48 is elevated enough to melt the ice in contact with the fingers 48 through operation of the pressure regulator 72. The pressure regulator 72 is operable to close, or at least partially restrict the fluid flow path from the ice maker evaporator coils 74 back to the compressor 66. This interference of the fluid flow elevates the pressure within the ice maker evaporator coils 74 above the low pressure required to maintain the temperature of the fingers 48 below 32° F. If the pressure within the ice maker evaporator coils 74 is elevated, the pressure drop across the ice maker expansion valve 68 is less than what it is under normal operating conditions when the finger temperature is maintained below 32° F. When the pressure within the ice maker evaporator coils 74 is so elevated, evaporation of the refrigerant therein is impeded, thereby minimizing the amount of thermal energy withdrawn from the fingers 48 by the refrigerant and causing the temperature of the fingers 48 to rise above 32° F.
For embodiments including the common connection point 76 at which the refrigerant returned from each of the ice maker refrigeration circuit 52 and the fresh food refrigeration circuit 56, adjusting the pressure of the returning refrigerant could potentially affect operation of the fresh food refrigeration circuit 56. To minimize any effect caused by pressure fluctuations caused by operation of the pressure regulator 72, a unidirectional fluid flow limiting device 80 such as a check valve, for example, is provided between the common connection point 76 and the fresh food compartment evaporator coils 64. The unidirectional fluid flow device 80, also referred to herein as a check valve 80, substantially isolates any pressure fluctuations caused by the pressure regulator 72 from the fresh food compartment evaporator coils 64 until such fluctuations are resolved. However, in the absence of any such pressure fluctuations, the check valve 80 passes refrigerant flowing from the fresh food compartment evaporator coils 64 back to the compressor 66 without significant interference.
For the illustrative arrangement of the refrigeration circuits 52, 56 shown in
To expedite the release of the ice from the fingers 48, compressed refrigerant can be delivered via a bypass conduit 82 from the compressor 66 to the ice maker evaporator coils 74 without entering the ice maker expansion valve 68. In doing so, the refrigerant has not experienced the pressure drop across the ice maker expansion valve 68, and thus, has a temperature that is higher than it would be had it had gone through the ice maker expansion valve 68 before entering the ice maker evaporator coils 74, but in any event higher than 32° F. The compressed refrigerant delivered to the ice maker evaporator coils 74 via the bypass conduit 82 sufficiently elevates the temperature of the exposed surface of the fingers 48 to at least partially melt the ice frozen thereto, allowing the ice to fall under the force of gravity into the bin 34.
Although the bypass conduit 82 bypasses the ice maker expansion valve 68 in
Yet other embodiments of the present invention, such as that illustrated in
Referring once again to
According to an embodiment of the refrigeration appliance 10, the repeated submergence of the portions of the fingers 48 is accomplished by controlling operation of a valve, pump 86, which may be a reversible gear pump or any other suitable bi-directional pump 86 in fluid communication with the hose 45, for example, or other suitable device for controlling the flow of water. Operated in a first direction, the pump 86 pumps water from the water supply into the water tray 38, and operated in a second direction opposite the first direction, the pump 86 pumps water from the water tray 38 back to the water supply or to a drain (not shown). The position of the water tray 38 relative to the fingers 48 during formation of the ice is fixed, and the fingers 48 can be stationary as well.
Repeatedly submerging at least the portions of the fingers 48 in the water by varying operation of the pump 86 as described above causes the depth of the water within the water tray 38 to rise above the lowermost portions of the fingers 48, and then recede to a lower level that exposes at least some, and preferably all of the formerly submerged portions of the fingers 48.
After remaining submerged in the water for a predetermined period of time, the pump 86 is operated in the second direction to remove a portion of the water from the water tray 38 in order to establish a shallow water depth D2 therein. With the water at the shallow water depth D2, at least a portion of the fingers 48 and any associated ice frozen thereto are then exposed to the ambient air above the water, said ambient air being maintained at a temperature within the range of about 32° F. to about 55° F. Repeating this submergence and emergence of the fingers 48 results in the gradual formation of ice cubes 88 that are formed in sequential layers built radially outward and that are substantially-transparent.
Alternate embodiments of repeatedly submerging at least a portion of the fingers 48 in the water include repeatedly adjusting the position of at least one of water tray 38 and the set of fingers 48 relative to the other. For example, the frame 50 supporting the fingers 48 or the water tray 38 could be operatively coupled to an electric motor (not shown) for repeatedly adjusting the position of the fingers 48 relative to water within the water tray 38, and then back again.
A method of making substantially-transparent ice within a fresh-food compartment 14 of a refrigeration appliance will be described with reference to the flow diagram shown in
Water is introduced into the water tray 38 within the fresh-food compartment 14 to establish a water depth within the tray 38 at step 120. The water introduced to the water tray 38 can have a temperature that is greater than 40° F., and optionally greater than or equal to about 50° F. to permit gases to escape the water before that water freezes to the fingers 48. At least a portion of each finger 48 is submerged within the water at step 130. The submergence of the portion of each finger 48 can be accomplished by adding water to the water tray 38 until the water depth encompasses the portions of the fingers 48, raising and lowering the water tray 38 holding a fixed amount of water relative to stationary fingers 48, or any other suitable method.
After being at least partially submerged, the submerged portions of the fingers 48 are removed from the water at step 140. Removing the fingers 48 from the water can be accomplished by performing the complement to the step that was performed to submerge the portion of each finger 48. For example, if water was added to the stationary tray 38 until the portions of the fingers 48 were submerged, then the water can be drained until the fingers are removed from the water.
At step 150 it is determined whether there has been a desired amount of ice formation on the submerged portions of the fingers 48. If so, the water is removed from the water tray 38 and the water tray 38 is pivoted about axis 46-46 to allow ice falling from the fingers 48 to land in the bin 34 at step 160. The finger temperature is elevated at step 170 by adjusting the pressure within the ice maker evaporator coils 74, transporting a hot gas to the fingers 48, resistively heating the fingers 48, or any other suitable method, and the ice in direct contact with the exposed surface of the fingers 48 is at least partially melted. When this ice is melted the cubes 88 can fall into the bin 34.
If, however, at step 150 it is determined that there has not yet been a desired amount of ice formation on the fingers, then the process repeats the submergence of the portions of the fingers 48 in the water at step 130. This process is repeated until a desired amount of ice is formed on the fingers 48. The desired amount of ice can be detected based on the weight of the ice cubes 88 frozen to the fingers 48, based on the amount of time that the cubes 88 were allowed to freeze, based on a number of times the fingers were repeatedly submerged in the water, based on a sensed temperature of the fingers 48, or any other suitable way of determining an amount of ice that has formed on the fingers 48.
Illustrative embodiments have been described, hereinabove. It will be apparent to those skilled in the art that the above devices and methods may incorporate changes and modifications without departing from the general scope of this invention. It is intended to include all such modifications and alterations within the scope of the present invention.
This application claims the benefit of U.S. Provisional Patent Application No. 61/156,502 filed on Feb. 28, 2009, the entire disclosure of which is hereby incorporated herein by reference.
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| Number | Date | Country | |
|---|---|---|---|
| Parent | 12714044 | Feb 2010 | US |
| Child | 12902606 | US |
