WO2008150104A2

WO2008150104A2 - Apparatus for supercooling and method for making porous ice using the same

Info

Publication number: WO2008150104A2
Application number: PCT/KR2008/003137
Authority: WO
Inventors: Su-Cheong Kim; Jong-Min Shin; Deok-Hyun Youn; Cheol-Hwan Kim; Won-Young Chung; Hoon-Bong Lee
Original assignee: Lg Electronics, Inc.
Priority date: 2007-06-04
Filing date: 2008-06-04
Publication date: 2008-12-11
Also published as: WO2008150104A3

Abstract

A supercooling apparatus is provided to make porous ice of enhanced texture by forming an abundance of air bubbles in the ice. The supercooling apparatus comprises: a container for storing liquid in a supercooled state; a phase converter for giving a shock to freeze a supercooled liquid in the container; and a drain hole formed in the container to discharge liquid. Through this configuration, a supercooled state is forced to be released, most supercooled water remaining in a liquid phase even after the lapse of a predetermined period of time is drained, and water in a solid phase in the container is frozen rapidly while having air bubbles remained between solid portions. In result, porous ice of better texture is produced.

Description

APPARATUS FOR SUPERCOOLING AND METHOD FOR MAKING POROUS ICE USING THE SAME

Technical Field

[1] The present invention relates to a supercooling apparatus for making porous ice of enhanced texture due to an abundance of air bubbles. Background Art

[2] Supercooling is a phenomenon that a liquid is not transited to a solid even below its phase transition temperature but maintained in a high temperature phase, i.e. a liquid phase. For example, water drops are supercooled in natural conditions. Incidentally, water or a beverage does not freeze but may remain in a supercooled state even in a freezer compartment of the ordinary refrigerator. A freezing method disclosed under Japan Laid-Open Patent Official Gazette S59-151834 and a freezing method and a refrigerator disclosed under Japan Laid-Open Patent Official Gazette 2001-086967 incorporate supercooling principles into the refrigerator. Both provide a technique for keeping foods in a supercooled state below the phase transition temperature by applying an electric field or a magnetic field to the foods in the refrigerator. Moreover, an electrostatic field treatment method disclosed under International Publication Official Gazette WO/98/41115 suggests diverse types of electrode structures that are suitable for freezing and thawing foods.

[3] FIG. 1 shows an apparatus for making transparent ice disclosed under Korea Laid-

Open Patent Official Gazette 2006-0013721. A transparent ice making apparatus 100 includes a supercooling means 120 using blades 122; and an ice-making means 110 constituted by an ice tray 111, ice-making compartments 112, a rotation axis 114, an ejector 113, and a heater 117, where a small amount of supercooled water provided from the supercooling means 120 is distributed evenly in each compartment to bank up thin plate ice and make transparent ice. Removing ice cubes from the ice tray 111 is done by applying heat from the heater 117 to the ice tray 111 to melt the ice slightly, which makes it easier to separate ice from the ice tray 111. Then, the rotation axis 114 is rotated to let the ejector 113 actually separate ice cubes from the ice tray 111.

[4] However, this ice-making apparatus uses a mechanical system such as blades to prepare supercooled water, and the supercooled water is divided into a small amount to make thin plate ice. Therefore, the ice-making apparatus was not so suitable for making slush rapidly or making ice. Disclosure of Invention Technical Problem [5] The present invention is conceived to solve the aforementioned problems in the prior art. An object of the present invention is to provide a supercooling apparatus for making ice of enhanced texture.

[6] Another object of the present invention is to provide a supercooling apparatus for making porous ice that contains an abundance of air bubbles.

[7] Still another object of the present invention is to provide a supercooling apparatus having a mechanism to apply an energy field to a water container where water used for making ice is kept, so that the water in the container may stay in a supercooled state.

[8] Yet another object of the present invention is to provide a supercooling apparatus for making porous ice by converting supercooled water into slush and then discharging liquid only, and a method of making porous ice using the same. Technical Solution

[9] According to an aspect of the present invention, there is provided a supercooling apparatus, including: a container for storing liquid in a supercooled state; a phase converter for giving a shock to freeze a supercooled liquid in the container; and a drain hole formed in the container to discharge liquid. Through this configuration, a supercooled state is forced to be released, most supercooled water remaining in a liquid phase even after the lapse of a predetermined period of time is drained, and water in a solid phase in the container is frozen rapidly while having air bubbles remained between solid portions. Accordingly, porous ice of better texture is produced.

[10] In an exemplary embodiment of the present invention, the supercooling apparatus of further includes a filter member for preventing a solid portion produced by freezing the liquid from leaking through the drain hole. Through this configuration, frozen solid is not discharged, and appreciable amounts of porous ice can be produced.

[11] In an exemplary embodiment of the present invention, the supercooling apparatus further includes: an energy generator for supplying energy to let the liquid in the container stay in a supercooled state; and a chilled air passage for supplying chilled air around the container, thereby keeping the liquid in the container at a low temperature. This configuration interrupts the phase transition of the liquid stored in the container at the phase transition temperature or below, allowing the liquid to stay in a supercooled state.

[12] In an exemplary embodiment of the present invention, the energy generator includes electrodes for generating an electric field, and a power supply for applying a high voltage to the electrodes.

[13] In an exemplary embodiment of the present invention, the supercooling apparatus further includes a sensor attached to the container, for detecting a state of the stored liquid. Through this configuration, the state of the liquid in the container is detected, and when the liquid reaches a supercooled state, the supercooled liquid can be frozen rapidly.

[14] In an exemplary embodiment of the present invention, the phase converter produces a freezing nucleus by giving a shock to a supercooled liquid.

[15] In an exemplary embodiment of the present invention, the phase converter gives an electric shock or a physical shock to a supercooled liquid.

[16] In an exemplary embodiment of the present invention, the supercooling apparatus further includes: an outlet formed in the container, through which a frozen slush produced by giving a shock to supercooled water is discharged; and a tray, into which the slush coming out through the outlet falls. Through this configuration, the liquid can be collected again to the container and preserved in a supercooled state, while the slush is being frozen in the tray. The tray may have divider compartments to produce ice cubes of a certain volume.

[17] In an exemplary embodiment of the present invention, the supercooling apparatus further includes a chilled air passage for supplying chilled air around the tray to let the slush in the tray freeze. This configuration makes it possible to freeze the slush contained in the tray.

[18] Another aspect of the present invention provides a method of making porous ice using a supercooling apparatus, including; a step for maintaining liquid in a supercooled state, while preventing the liquid from freezing; a step for releasing the supercooled state of the liquid to start freezing; and a step for draining non-frozen liquid. Through this method, porous ice containing an abundance of air bubbles can be produced.

[19] In an exemplary embodiment of the present invention, the draining step includes: a process of starting a liquid draining function; and a process of ending the liquid draining function. Through this method, pores are formed between the frozen solid following the discharge of the liquid, and porous ice can be obtained.

[20] In an exemplary embodiment of the present invention, before starting the liquid draining function, the draining step further includes: a process of detecting a frozen degree of the stored liquid. Through this method, one can adjust the degree of freezing and the amount of air bubbles to be contained in porous ice.

[21] In an exemplary embodiment of the present invention, the draining step includes a process of comparing duration of freezing time with a preset time. Through this method, one can control the duration of freezing time for the liquid to thus adjust the amount of air bubbles to be contained in porous ice.

[22] In an exemplary embodiment of the present invention, the preset time is a predetermined time or a time set by a user. This method allows a user for himself to adjust the amount of air bubbles to be contained in porous ice. [23] In an exemplary embodiment of the present invention, the method further includes a step of rapidly freezing a remainder of the liquid and the solid. Through this method, porous ice can be produced within a short period of time.

[24] In an exemplary embodiment of the present invention, the method further includes the steps of: a step for discharging a remainder of the liquid and the solid into a tray; and a step for rapidly freezing the liquid and solid in the tray. Through this method, continuous production of porous ice is possible by having the water in the container stay in a supercooled state and producing porous ice of a proper volume in the tray at the same time.

Advantageous Effects

[25] The supercooling apparatus and the method of making porous ice using the same according to the present invention enhance texture of ice by letting the ice contain an abundance of air bubbles.

[26] In addition, the supercooling apparatus and the method of making porous ice using the same according to the present invention provide diverse textures of ice by regulating an amount of air bubbles to be contained in porous ice.

[27] Moreover, the supercooling apparatus and the method of making porous ice using the same according to the present invention are capable of producing porous ice continuously by preparing a supercooled liquid, while making porous ice. Brief Description of the Drawings

[28] FIG. 1 shows a conventional ice-making device;

[29] FIG. 2 conceptually shows a process for slush production or supercooling according to the present invention;

[30] FIG. 3 shows one of results of an experiment conducted according to the present invention;

[31] FIG. 4 is a partial view of a supercooling apparatus according to a preferred embodiment of the present invention;

[32] FIG. 5 shows one of results of an experiment actually conducted according to the present invention; and

[33] FIG. 6 through FIG. 8 are flow charts describing a first through a third embodiment of a method of making porous ice using a supercooling apparatus of the present invention, respectively.

[34]

Mode for the Invention

[35] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[36] FIG. 2 is a conceptual view of a process for slush production or supercooling in ac- cordance with the present invention. Referring to FIG. 2, a target liquid 41 to be supercooled is positioned between electrodes 40. While chilled air 42 is being supplied, an AC power supply 43 applies an electric field to the liquid 41. In result, the liquid 41 does not freeze at its phase transition temperature (e.g., 0⁰C for water under 1 atm pressure) or below, but stays in a supercooled state. It is known that water, which consists of an oxygen atom and two hydrogen atoms, can be supercooled and not frozen particularly when energy such as an electric field is supplied because the energy supply interrupts hydrogen bonding of water. However, when an external force is applied to the supercooled liquid by a phase converter 44 (e.g., an igniter exerts an electric force on the supercooled liquid), the force disturbs the supercooled state which has been maintained by the energy being supplied or has been supplied to the supercooled liquid (this implies that a supercooled state can be maintained in some conditions even if the energy supply is stopped after a predetermined amount of time). Accordingly, freezing nucleus are formed, and the supercooled liquid is rapidly converted into a solid phase, producing slush. At this time, temperature of the supercooled liquid changes from temperature in the supercooled state to a phase transition temperature.

[37] The following will now provide the results of an experiment that is actually conducted in accordance with the present invention.

[38] 1. Installation of Electrodes and Container

[39] Two electrodes of 100mm in width and length were arranged 200mm apart from each other. A container filled with IL water was positioned between those two electrodes with a certain distance from each.

[40] 2. Supercooling Process

[41] The thusly prepared unit was placed in a refrigerator having a temperature of -6.8°C, and an electric field was applied at the frequency of 4OkHz and 2kV. When the unit was put in the refrigerator, the electric field was applied at the same time. After giving a sufficient time to a supercooling process, one used an electric igniter for a 1500V electric lighter to heat and convert the supercooled liquid into a solid phase. The results are shown in FIG. 5.

[42] FIG. 3 shows one of the results obtained from an experiment conducted according to the present invention. In detail, a graph in FIG. 3 shows a correlation between the applied power and the temperature of the supercooled liquid. As can be seen from the graph, an almost linearly proportional relationship exists between two. This indicates that, in a given ambient temperature, one can control a preset temperature of the supercooled liquid by regulating power being provided from an energy generator.

[43] FIG. 4 is a partial view of a supercooling apparatus according to the present invention, in which a container 21, a tray 22, and a band 23 are installed in order from top to down of a freezer compartment door 20. The container 21 is where water is supercooled and stays. Electrodes 21a, serving as an energy generator, are installed around the container 21 in order to apply energy through an electric field. A water supply passage 21b is connected to supply water, and a valve 21c for controlling a water flow rate to the container 21 is installed on the water supply passage 21b. Further, an electric igniter 22c, serving as a phase converter, is provided nearby the container 21 to cause a phase transition of water stored in the container 21. The electric igniter 22c is positioned in a way to be able to give an electric shock to the supercooled water in the container 21, and converts the supercooled water into a solid phase, producing slush.

[44] Meanwhile, the container 21 has a drain hole 2 Ig in the bottom to discharge liquid water that has not converted into a solid phase under an electric shock from the electric igniter 22c. The drain hole 2 Ig is connected to a drain passage 2 Ie. When a predetermined period of time elapses after giving the electric shock from the electric igniter 22c, the water in the container exists both in a solid phase of a suitable size and in a liquid phase. Here, under the control of a drain valve 2 If the liquid water is drained via the drain hole 21g and the drain passage 21e to the outside of the container 21. The container 21 further includes a filter member 2 Ig for covering the drain hole 2 Ig, so that the frozen, solid water cannot be discharged through the drain hole 2 Ig. When the draining function is completed, only an extremely small amount of the water in a liquid phase is left in the container 21, and pores are formed between the water in a solid phase. That is, the container 21 has the water frozen into a slush state.

[45] There is another valve 2 Id in the bottom of the container 21 to control the supply of water in a slush state to the tray 22. The tray 22 is provided with chilled air to cause the water in a slush state to completely freeze. If the water in a slush state freezes rapidly, gas in the solid phase water remains to produce porous ice.

[46] The tray 22 is installed to be able to rotate, and its rotation is controlled by a motor

22a. Preferably, the tray 22 is made out of a conductive material such as aluminum, and has a heater 22b in the bottom thereof to facilitate ice separation. The tray 22 is divided into a number of compartments defined by divider walls (or partitions) 22d. Grooves are formed on connecting parts 22e to enable the supercooled liquid to communicate, such that the electric shock given to a specific spot may spread out evenly throughout the entire supercooled water. Below the tray 22, there is the bank 23 into which slush or ice cubes from the rotating tray 22 fall down.

[47] A sensor 21i for detecting the state of water in the container 21 is installed at one side of the container 21. The sensor 2 Ii measures the water temperature, frozen degree of water, electric field intensity, etc., and sends the information to a controller (not shown). Based on the received information, the controller (not shown) controls whether to operate the electric igniter 22c, the drain valve 2 If, and the valve 2 Id.

[48] FIG. 6 is a flow chart describing a first embodiment of a method of making porous ice using a supercooling apparatus according to the present invention. In step Sl, water is controlled to stay in a supercooled state and stored in the container 21. In step S2, according to a command from the controller (not shown) or a command a user has input through a control panel (not shown), the water in the container 21 starts freezing. When the supercooled state water in the container is hit by shock from the electric igniter 22c, it starts freezing. The water in the container is in a frozen, solid phase as well as in a non-frozen, liquid phase. In step S3, only the water in a liquid phase is discharged. In result, the water in a frozen, solid phase, an extremely small amount of the water in a liquid phase, and the water in a supercooled state containing pores produced when discharging the liquid water remain in the container 21. In step S4, the water in a slush state is frozen rapidly to obtain porous ice.

[49] FIG. 7 is a flow chart describing a second embodiment of a method of making porous ice using a supercooling apparatus according to the present invention. According to this method, in step S 1 water is controlled to stay in a supercooled state and stored in the container 21. In step S2, according to a command from the controller (not shown) or a command a user has input through a control panel (not shown), the water in the container 21 starts freezing. When the supercooled state water in the container is hit by shock from the electric igniter 22c, it starts freezing. In step S3 for draining only the liquid water, the sensor 2 Ii detects a frozen degree of the water in the container 21 (Pl); the liquid water starts being discharged (P2) if a predetermined percentage or above of the water is frozen or if frozen water droplets(or particles) have grown to a predetermined size or larger in diameter; and the liquid water draining process ends (P3) after a predetermined period of time elapses or when the percentage of the liquid water drops to a predetermined level or below. Consequently, the water in a frozen, solid phase, an extremely small amount of the water in a liquid phase, and the water in a supercooled state containing pores produced when discharging the liquid water remain in the container 21. In step S4, the valve 2 Id is opened to let the water in a slush state flow into the tray 22. By circulating chilled air at the water's phase transition temperature or below around the tray 22, the water in a slush state freezes in the tray 22 and porous ice (cubes) are produced.

[50] FIG. 8 is a flow chart describing a third embodiment of a method of making porous ice using a supercooling apparatus according to the present invention. According to this method, in step S 1 water is controlled to stay in a supercooled state and stored in the container 21. In step S2, according to a command from the controller (not shown) or a command a user has input through a control panel (not shown), the water in the container 21 starts freezing. When the supercooled state water in the container is hit by shock from the electric igniter 22c, it starts freezing. In step S3 for draining only the liquid water, duration of water freezing time is compared with a preset time (Pl); the liquid water draining process starts (P2) if the freezing time is equal or longer than the preset time; and the liquid water draining process ends (P3) after a predetermined period of time elapses or when the percentage of the liquid water falls to a predetermined level or lower. Consequently, the water in a frozen, solid phase, an extremely small amount of the water in a liquid phase, and the water in a supercooled state containing pores produced when discharging the liquid water remain in the container

21. In step S4, the valve 2 Id is opened to let the water in a slush state flow into the tray

22. By circulating chilled air at the water's phase transition temperature or below around the tray 22, the water in a slush state freezes in the tray 22 and porous ice (cubes) are produced.

[51] The present invention has been described in detail with reference to the embodiments and the attached drawings. However, the scope of the present invention is not limited to the embodiments and the drawings, but defined by the appended claims.

Claims

[I] A supercooling apparatus, comprising: a container for storing liquid in a supercooled state; a phase converter for giving a shock to freeze a supercooled liquid in the container; and a drain hole formed in the container to discharge liquid. [2] The supercooling apparatus of claim 1, further comprising: a filter member for preventing a solid portion produced by freezing the liquid from leaking through the drain hole. [3] The supercooling apparatus of claim 1, further comprising: an energy generator for supplying energy to let the liquid in the container stay in a supercooled state; and a chilled air passage for supplying chilled air around the container, thereby keeping the liquid in the container at a low temperature. [4] The supercooling apparatus of claim 3, wherein the energy generator includes electrodes for generating an electric field, and a power supply for applying a high voltage to the electrodes. [5] The supercooling apparatus of claim 1, further comprising: a sensor attached to the container, for detecting a state of the stored liquid. [6] The supercooling apparatus of claim 1, wherein the phase converter produces a freezing nucleus by giving a shock to a supercooled liquid. [7] The supercooling apparatus of claim 6, wherein the phase converter gives an electric shock or a physical shock to a supercooled liquid. [8] The supercooling apparatus of claim 6, further comprising: an outlet formed in the container, through which a frozen slush produced by giving a shock to supercooled water is discharged; and a tray, into which the slush coming out through the outlet falls. [9] The supercooling apparatus of claim 8, further comprising: a chilled air passage for supplying chilled air around the tray to let the slush in the tray freeze. [10] A method of making porous ice using a supercooling apparatus, comprising: a step for maintaining liquid in a supercooled state, while preventing the liquid from freezing; a step for releasing the supercooled state of the liquid to start freezing; and a step for draining non-frozen liquid.

[I I] The method of claim 10, wherein said the step for draining includes: a process of starting a liquid draining function; and a process of ending the liquid draining function. [12] The method of claim 11, wherein, before starting the liquid draining process, said draining further includes: a process of detecting a frozen degree of the stored liquid. [13] The method of claim 11, wherein said draining includes: a process of comparing duration of freezing time with a preset time. [14] The method of claim 13, wherein the preset time is a predetermined time or a time set by a user. [15] The method of claim 10, further comprising: a step for rapidly freezing a remainder of the liquid and the solid. [16] The method of claim 10, further comprising: a step for discharging a remainder of the liquid and the solid into a tray; and a step for rapidly freezing the liquid and solid in the tray.