JP5135576B2 - Ice making equipment - Google Patents

Description

  The present invention relates to a liquid solidification method, an ice making method, and an ice making device.

  A product obtained by solidifying a substance that is liquid at room temperature, for example, ice formed by freezing water, can be easily obtained by a refrigerator-freezer widely used in general households. However, ice frozen by a refrigerator-freezer popular in ordinary households is polycrystalline and does not become single crystal ice.

  Single crystal ice is highly transparent and beautiful, so it has a high commercial value as ice. Single crystal ice also has a characteristic that it is hard and difficult to defrost. Because of these characteristics, techniques for obtaining single crystal ice by various methods have been disclosed in the prior art (see, for example, Patent Document 1).

Further, paying attention to the fact that the coefficient of friction of a surface orthogonal to the crystal orientation of ice cake which is single crystal ice is low, a method for artificially producing ice cake has been disclosed (for example, see Patent Document 2).
JP-A-5-264137 Japanese Patent Laid-Open No. 11-236295

  However, in the ice making device disclosed in Patent Document 1, water is gradually frozen in a stationary state or a fluid state on an ice making plate that is a low-temperature heat source. In such an ice making apparatus, single crystal ice having an arbitrary shape could not be manufactured even though single crystal ice could be manufactured. In addition, when water is frozen on an ice plate, it is not easy to remove the ice from the ice plate after freezing.

  In the invention disclosed in Patent Document 2, single crystal ice that freezes can be manufactured in a bowl shape, but single crystal ice of any shape cannot be manufactured. Also, the orientation of ice crystals could not be controlled.

  This invention is made | formed in view of the situation mentioned above, and makes it a subject to provide the ice making method and ice making apparatus which can manufacture single crystal ice with high hardness and transparency and high commercial value with arbitrary shapes continuously. .

The invention of the ice making device according to claim 1 includes a container having an opening in an upper part, a vacuum tank covering the opening, a Peltier element provided on the vacuum tank, and a buffer communicating with the inside of the container. And water in the container filled up to contact with a lower plate of the vacuum chamber placed on the upper edge of the container is frozen in single crystal ice.

According to a second aspect of the invention, the ice making apparatus of claim 1, is characterized in that attached to the heat radiating member on the Peltier element.

A third aspect of the invention is the ice making device according to the first or second aspect , wherein the container includes an inner container and an outer container, and a heat insulating container in which a gap between the inner container and the outer container is evacuated. It is characterized by this.

According to a fourth aspect of the present invention, in the ice making device according to the first or second aspect , the vacuum vessel and the container are covered with a vacuum heat insulating material .

The invention according to claim 5 is the ice making device according to any one of claims 1 to 4 , wherein the vacuum degree in the vacuum chamber is approximately 0.01 atm.

According to a sixth aspect of the invention, the ice making apparatus according to any one of claims 1 to 5, is characterized in that it comprises at least one or more temperature detectors.

According to the present invention, it is possible to realize a solidification method and an ice making method capable of continuously producing single crystal ice that is hard, has high transparency, and has high commercial value. Further, since ice making can be performed at an atmospheric temperature somewhat higher than 0 ° C., an ice making method can be realized in which freezing adhesion to the ice making container is weak and ice can be easily taken out from the ice making container.

According to the present invention, it is possible to realize an ice making apparatus that can continuously produce single-crystal ice having a hard shape, high transparency, and high commercial value.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. FIG. 1 is a longitudinal sectional view showing an ice making device 10 as an embodiment of the present invention. 2 is a cross-sectional view taken along the line AA in FIG. In this example, an experiment was conducted using water because it is inexpensive as a liquid, easy to handle, and easily available.

  In FIG. 1, a container 12 for storing water 11 to be frozen has a bottomed cylindrical shape, and the periphery except for the upper opening 13 is covered with a heat insulating material 14. Although the horizontal cross-sectional shape of the container 12 is a rectangle, it may be a polygon other than a rectangle or a simple circle. A hole 15 is provided in a side surface near the bottom of the container 12, and one end 16a of a pipe 16 extending to the outside of the heat insulating material 14 is liquid-tightly connected to the hole 15. A buffer container 17 is liquid-tightly connected to the other end 16b of the pipe 16. Although the container 12 can be manufactured using a metal material such as stainless steel, in this embodiment, it was manufactured using a transparent acrylic resin. The material of the pipe 16 that connects the container 12 and the buffer container 17 is preferably low in thermal conductivity, and it is preferable to use a non-metallic material. This is because if the pipe 16 is made of a material having high thermal conductivity, the amount of heat transfer between the container 12 and the buffer container 17 through the pipe 16 increases.

  A box-shaped vacuum chamber 18 is disposed in the upper opening 13 of the container 12. The vacuum chamber 18 of this embodiment is rectangular in plan view corresponding to the shape of the container 12 as shown in FIG. 2, but may be other shapes such as a circle. What is important here is to cover the entire upper opening 13 of the container with a vacuum chamber 18. Therefore, in the present embodiment, the vacuum chamber 18 is manufactured with a plan view size larger than that of the opening 13 of the container 12. The periphery of the vacuum chamber 18 is covered with a heat insulating material 14 in the same manner as the container 12. As a result, heat can be prevented from flowing into the vacuum chamber 18 from the surroundings as much as possible.

  As the heat insulating material 14, a heat insulating material such as polystyrene foam can be used, but a vacuum heat insulating material commercially available as a general-purpose product can also be used. In the case where heat insulation performance is emphasized with a compact size, it is preferable to use a vacuum heat insulating container having an inner container and an outer container and having a vacuum between the inner container and the outer container. .

  In the present embodiment, the material of the vacuum chamber 18 is also a synthetic resin material as in the case of the container 12. The thicknesses of the upper plate 19 and the lower plate 20 constituting the vacuum chamber 18 are preferably as thin as possible from the viewpoint of increasing the efficiency of heat transfer. However, since atmospheric pressure acts on the outer surface of the vacuum chamber 18, if the plate thickness is too thin, the mechanical strength necessary and sufficient for the vacuum chamber cannot be secured, and there is a limit to reducing the plate thickness. In this embodiment, the thickness of the upper plate 19 and the lower plate 20 constituting the vacuum chamber 18 is 3 to 4 mm. The inside of the vacuum chamber 18 is set to a degree of vacuum of about 0.01 atm. The reason why the inside of the vacuum chamber 18 is reduced to a degree of vacuum of about 0.01 atm is to prevent the convection phenomenon due to the presence of air molecules. Therefore, it is sufficient that the degree of vacuum inside the vacuum chamber does not cause convection, and there is no need to increase the degree of vacuum more than necessary. For this reason, the degree of vacuum is set as described above.

  A Peltier element 21 serving as a low-temperature heat source is placed on the upper plate 19 of the vacuum chamber 18, and a heat sink 23 serving as a radiator 22 and an electric fan 24 are provided on the Peltier element 21. Of both surfaces of the flat Peltier element 21, the surface on the low temperature side is in contact with the upper plate 19 of the vacuum chamber, and the surface on the high temperature side is in contact with the lower surface of the heat sink 23. The electric fan 24 is mounted on the upper surface of the heat sink 23. However, the electric fan 24 is for efficiently radiating heat from the heat sink 23, and when the heat sink 23 alone can secure sufficient heat radiating performance. The electric fan 24 can be omitted.

  Further, in this embodiment, thermocouples as temperature detectors are disposed at appropriate positions in order to grasp the temperatures of the respective parts in the container 12 and the temperatures of the respective parts in the vacuum chamber 18. Specifically, one thermocouple is disposed in each of the upper part 25 and the lower part 26 in the container and the upper part 27 and the lower part 28 in the vacuum chamber. In addition, thermocouples are also provided in the low temperature side 29 of the Peltier element and in the vicinity 30 of the ice making device for measuring the ambient temperature.

  Next, a method for producing ice from water that is liquid using the above-described ice making apparatus 10 will be described. Prior to the start of the operation of the ice making device 10, the container 12 is filled with water 11. Water 11 is filled up to the upper opening 13 of the container 12. Specifically, water 11 can be filled into the container 12 by injecting water from the buffer container 17. The upper end of the container 12 is provided with pores (not shown) as an air vent so that water can be completely filled up to the upper opening 13 of the container 12. Therefore, water 11 can be filled into the container 12 by injecting water 11 from the buffer container 17 and confirming that water overflows from the pores and plugging the pores. At this time, the water surface level 31 in the buffer container 17 is equal to the height of the container opening 13. The original purpose of installing the buffer container 17 is to absorb the volume change when the water 11 in the container 12 freezes.

  Here, the ambient temperature in which the ice making apparatus 10 is installed is preferably controlled to about 2 ° C. Even if the ambient temperature is room temperature, it will not be impossible to make ice, but if the temperature difference between the temperature in the container 12 and the ambient temperature becomes large, wasteful heat transfer will occur and the time required for ice making will become longer and extra This is because there is a demerit that consumes a lot of power.

  When the Peltier element 21 and the electric fan 24 are energized, the lower side of the Peltier element 21, that is, the portion in contact with the upper plate 19 of the vacuum chamber 18 is cooled to about −26 ° C. On the other hand, the temperature of the upper side of the Peltier element 21, that is, the portion in contact with the heat sink 23 rises to the ambient temperature or higher, and the generated heat is transferred to the air flow generated by the electric fan 24 and radiated.

When the upper plate 19 of the vacuum chamber is cooled to about −26 ° C. by the Peltier element 21, a large temperature difference is generated between the upper plate 19 and the lower plate 20 of the vacuum chamber. Since the lower plate 20 of the vacuum chamber is placed on the upper edge of the container 12, and the lower surface of the lower plate 20 is in contact with the water 11, the temperature of the lower plate 20 is equal to the temperature of the water 11 in the container, and the Peltier element At the stage when energization is started at 21, the temperature is about 10 ° C. On the other hand, since the vacuum chamber 18 is depressurized to about 0.01 atm, heat transfer occurs due to air convection even if there is a large temperature difference between the upper plate 19 and the lower plate 20 of the vacuum chamber. Absent. The heat transfer between the upper plate 19 and the lower plate 20 of the vacuum chamber is limited to the heat transfer by radiation from the high temperature lower plate 20 side to the low temperature upper plate 19 side.

  3-5 is data which shows transition of each part temperature during the driving | operation of the ice making apparatus 10 by a present Example. In each figure, the horizontal axis indicates the elapsed operation time of the icing device 10, and the vertical axis indicates the temperature. As shown in FIG. 3, the low temperature side of the Peltier element 21 is rapidly cooled to a temperature of about −26 ° C. after the start of operation. Although the atmospheric temperature was recorded for reference, the atmospheric temperature is maintained at about 2 ° C.

  In FIG. 4, the temperatures of the upper part 27 and the lower part 28 in the vacuum chamber are recorded. Both the upper 27 temperature and the lower 28 temperature in the vacuum chamber rapidly decrease to about 2 ° C. or less in about 1 hour after the start of operation. After that, the temperature of about 0 ° C. to 2 ° C. is maintained, but the upper 27 temperature transitions about 1 ° C. lower than the lower 28 temperature in the vacuum chamber. The reason for this is that although there is no heat transfer due to air convection in the vacuum chamber, the upper portion 27 of the vacuum chamber is close to the Peltier element 21, which is a low temperature heat source, and the lower portion 28 of the vacuum chamber is located on the water side, which is a high temperature heat source. Because it is close. Inside the vacuum chamber 18, heat transfer is performed by radiation from the lower side to the upper side.

  In FIG. 5, the temperature of the upper part 25 and the lower part 26 in the water tank which is the container 12 is recorded. The temperature of the upper part 25 gradually decreases and reaches 0 ° C. in about 3 hours after the start of operation. Thereafter, the temperature is maintained at around 0 ° C. The reason is that the upper part 25 freezes in about 3 hours after the start of operation. The temperature of the lower portion 26 decreases to about 2 ° C. in about 3 hours after the start of operation, but is maintained at about 2 ° C. even after 20 hours. The reason is that the lower portion 26 of the water tank is not frozen after 20 hours, so it cannot be below freezing point and is kept at a temperature slightly above 0 ° C.

  Since icing by the icing device 10 of the present invention is cooled by heat radiation from the upper opening 13 of the water tank, icing starts from the upper opening 13 of the water tank. The basin is similar to the phenomenon of freezing the surface of water in the basin in the morning when a basin filled with water in the severe winter season is left outdoors on a clear night. However, in this case, since it is cooling in the air, it goes without saying that there is also heat transfer by convection and heat conduction in addition to radiative cooling.

  FIG. 6 is data in which the thickness of frozen ice with respect to the elapsed time after the start of the operation of the icing device 10 is recorded. In this embodiment, freezing starts from the upper opening 13 of the water tank about 3 hours after the start of operation. Thereafter, the ice thickness increases with time, and the ice thickness reaches 25 mm after about 40 hours from the start of operation. The data shown in FIG. 6 is recorded by arranging a light source and a camera (not shown) in a part of the heat insulating material 14 covering the periphery of the container 12.

  When the ice obtained by the ice making apparatus 10 according to the present example was taken out and the crystal structure of the ice was observed with a microscope, it was confirmed that the crystal structure was a single crystal. The inventor of the present invention repeated the experiment while changing various experimental conditions in order to confirm whether the single crystal ice was made by chance. For example, experiments were carried out using distilled water and normal tap water as icing targets, and it was confirmed that single crystal ice was formed in any case. In addition, ice making was attempted both when the ice making apparatus was operated with seed ice in the water tank and when it was operated without seed ice. As a result, it was confirmed that single crystal ice could be produced in any case. According to the ice making device of the present invention, single crystal ice can be produced with sufficient reproducibility, but no theoretical clarification has been made as to why single crystal ice is formed.

  According to the ice making method of the above-described embodiment, it is possible to realize a solidification method and an ice making method capable of continuously producing single crystal ice that is hard, has high transparency, and has high commercial value. In addition, since ice making can be performed at an ambient temperature somewhat higher than 0 ° C., an ice making method can be realized in which freezing adhesion to the ice making container is weak and ice can be easily taken out from the ice making container.

  In addition, according to the ice making device 10 of the above-described embodiment, it is possible to continuously produce single-crystal ice having an arbitrary shape that is hard, has high transparency, and has a high commercial value.

  As mentioned above, although this invention was demonstrated based on the Example, this invention is not limited to the Example mentioned above, A various deformation | transformation implementation can be performed. In the above embodiment, water is used as the solidifying liquid, but it can also be applied to solidifying liquids other than water. For example, it can be applied to solidification of alcohol or the like.

It is sectional drawing of the freezing apparatus which shows the Example of this invention. It is an AA arrow line view of FIG. 1 which is an Example of this invention. It is a characteristic view which shows the ice making data by the ice making apparatus of this invention. It is data which shows each part temperature transition during the driving | operation of the ice making apparatus of this invention. It is data which shows each part temperature transition during the driving | operation of the ice making apparatus of this invention. It is data which shows each part temperature transition during the driving | operation of the ice making apparatus of this invention.

10 Ice making equipment
11 water
12 Container (aquarium)
13 Opening (upper opening)
14 Insulation (vacuum insulation)
17 Buffer container
21 Low temperature heat source (Peltier element)
22 radiator
25-30 Temperature detector (thermocouple)

Claims (6)

A container having an opening at the top; a vacuum tank covering the opening; a Peltier element provided on the vacuum tank; and a buffer container communicating with the inside of the container ; An ice making device characterized in that water in the container filled until it comes into contact with a lower plate of the placed vacuum tank is frozen into single crystal ice. Ice making apparatus of claim 1, wherein a fitted with a heat radiator on the Peltier element. The ice making apparatus according to claim 1 or 2 , wherein the container includes an inner container and an outer container, and is composed of a heat insulating container in which a gap between the inner container and the outer container is evacuated. The ice making device according to claim 1 or 2, wherein the vacuum vessel and the container are covered with a vacuum heat insulating material . The ice making device according to any one of claims 1 to 4 , wherein a degree of vacuum in the vacuum chamber is approximately 0.01 atm. The ice making device according to any one of claims 1 to 5 , further comprising at least one temperature detector.

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