Ice making device and ice making method

Abstract

To provide an ice making device with high refrigeration capacity.SOLUTION: An ice making device comprises: a disc part 26 in contact with an aqueous solution; a first refrigerant passage 29A formed so as to pass through the disc part 26 and capable of flowing a first refrigerant; and a second refrigerant passage 29B formed so as to pass through the disc part 26 and capable of flowing a second refrigerant having a lower evaporation temperature than that of the first refrigerant, where the disc part 26 cooled by the first refrigerant is cooled by the second refrigerant; the disc part 26 is immersed in the aqueous solution; and the pressure of the vaporized second refrigerant imparts fluidity to the second refrigerant.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to an ice-making device and method for producing flake ice used in ice slurries, for example. [Background technology]

[0002] For example, it is common to freeze fresh foods such as seafood and meat as frozen products and store or transport these frozen products. Ice slurry is used to freeze the frozen products, and the products are immersed in the ice slurry and instantly frozen to maintain the freshness of the food ingredients.

[0003] Patent Document 1, which will be described later, discloses that flake ice (ice flakes) is produced in a drum-type ice slurry raw material production apparatus (200) and that the flake ice is dropped into an ice storage tank (500) to produce ice slurry. Patent Document 1 further discloses that the ice slurry in the ice storage tank (500) is supplied to a refrigeration device (6) through an ice slurry supply pipe (45).

[0004] Flake ice manufacturing devices such as those disclosed in Patent Document 2 and Patent Document 3 are also known. These flake ice manufacturing devices are equipped with a metal ice making plate (also called a "metal ice plate," "metal plate," "ice making body," etc.). The metal ice making plate is used to freeze an aqueous solution of a solute such as salt, calcium chloride, or ethanol to manufacture flake ice, ice slurry, etc.

[0005] Also, the ice-making plate in Patent Document 2 has a drum-type configuration similar to the ice slurry raw material production apparatus (200) disclosed in Patent Document 1. Furthermore, the ice-making plate in Patent Document 3 has a plate-type configuration having a flat shape. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2019-207046 A [Patent Document 2] JP 2019-143905 A [Patent Document 3] JP 2019-143906 A Summary of the Invention [Problem to be solved by the invention]

[0007] Incidentally, in the ice slurry production apparatus 1 as disclosed in Patent Document 1 and the flake ice production apparatus as disclosed in Patent Documents 2 and 3, further improvement in the freezing capacity is desired. One possible way to improve the freezing capacity is to increase the fluidity of the refrigerant. However, it is not easy to dramatically improve the freezing capacity by increasing the fluidity of the refrigerant.

[0008] An object of the present invention is to provide an ice-making device and an ice-making method with high freezing capacity. [Means for solving the problem]

[0009] In order to solve the above problems, the present invention provides an ice making unit that is in contact with brine, a first refrigerant passage formed to pass through the ice making unit and capable of allowing a first refrigerant to flow; a second refrigerant passage formed to pass through the ice making unit and capable of flowing a second refrigerant having a lower evaporation temperature than the first refrigerant; The ice making device is characterized in that the ice making section, cooled by the first refrigerant, is cooled by the second refrigerant. In order to solve the above-mentioned problems, the present invention provides an ice-making method, comprising: passing a first refrigerant through an ice-making unit in contact with brine to cool the ice-making unit; switching to a second refrigerant having a lower evaporation temperature than the first refrigerant; and cooling the ice-making unit cooled by the first refrigerant with the second refrigerant. In order to solve the above problems, the present invention provides an ice making unit in contact with brine, a first refrigerant passage formed to pass through the ice making unit and capable of allowing a first refrigerant to flow; a second refrigerant passage formed to pass through the ice making unit and capable of flowing a second refrigerant having a lower evaporation temperature than the first refrigerant, The ice making method is characterized in that the ice making section is cooled by the first refrigerant and then cooled by the second refrigerant. Effect of the Invention

[0010] According to the present invention, an ice-making device and an ice-making method having high freezing capacity can be provided. [Brief description of the drawings]

[0011] [Figure 1] 1 is a perspective view showing an ice slurry production apparatus according to an embodiment of the present invention; [Diagram 2] FIG. 4 is a diagram for explaining the supply of a first refrigerant and the supply of a second refrigerant. [Diagram 3] FIG. 2(a) is a plan view showing a schematic diagram of a first embodiment of refrigerant piping in a disk portion, and FIG. 2(b) is a plan view showing a schematic diagram of a second embodiment of refrigerant piping in a disk portion. [Figure 4] FIG. 4 is an explanatory diagram in which a first refrigerant passage and a second refrigerant passage in a disk portion are distinguished by symbols. [Diagram 5] FIG. 13 is a side view showing a schematic view of the flow of the aqueous solution around the disk portion. [Figure 6] FIG. 1A is a side view showing the principle by which a buff of a first embodiment associated with the sweeping portion separates ice from a disk portion, and FIG. 1B is a side view showing the principle by which a metal plate of a second embodiment associated with the sweeping portion separates ice from a disk portion. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] An ice-making device according to an embodiment of the present invention will be described below with reference to the drawings. Note that an ice slurry production device will be described as the ice-making device. Fig. 1 shows a refrigeration system 10 according to a first embodiment of the present invention and an ice slurry production device 11 used in the refrigeration system 10. The refrigeration system 10 shown in Fig. 1 is configured by combining an ice slurry production device 11, a refrigeration tank 12, an aqueous solution pump 13, and the like.

[0013] Among these, the ice slurry production device 11 is capable of producing flake-shaped (also called thin pieces, flakes, small lumps, or granules) ice (flake ice) by precipitating ice from raw water (e.g., 50 weight % (wt%) ethanol aqueous solution) in the freezing tank 12. The freezing point of the ethanol aqueous solution is, for example, about -37°C or -50°C.

[0014] This ice slurry production apparatus 11 has a refrigerator 14, a flake ice production section 15 as an ice production section, and a refrigerant guide section 16. Furthermore, in ice slurry production apparatus 11, refrigerator 14, flake ice production section 15, and refrigerant guide section 16 are mounted on a frame section 17 as a holding section, and are integrated with each other.

[0015] The refrigerator 14, flake ice making section 15, and refrigerant guide section 16 of the ice slurry production device 11 constitute a refrigeration cycle, which circulates a predetermined refrigerant liquid (liquid refrigerant) to compress, condense, expand, and evaporate the refrigerant. Various common types of refrigeration cycles can be used.

[0016] A refrigerant (a first refrigerant described later) is sent from the refrigerator 14 to the flake ice producing section 15 via a refrigerant guide section 16. The refrigerant guide section 16 is equipped with a refrigerant inlet pipe 18a that introduces the refrigerant from the refrigerator 14 to the flake ice producing section 15, and a refrigerant outlet pipe 18b that returns the refrigerant discharged from the flake ice producing section 15 to the refrigerator 14.

[0017] The refrigerant inlet pipe 18a and the refrigerant outlet pipe 18b may be, for example, a general refrigerant pipe made of a copper pipe covered with a heat insulating material. The refrigerant inlet pipe 18a and the refrigerant outlet pipe 18b may be such a refrigerant pipe connected via a general pipe joint.

[0018] In this embodiment, each end of the refrigerant inlet pipe 18a and the refrigerant outlet pipe 18b is connected to the refrigerator 14 and the flake ice preparation unit 15 via piping joints (not shown in detail). The refrigerant inlet pipe 18a and the refrigerant outlet pipe 18b are bent so as to form an upwardly protruding inverted U-shape. The refrigerant inlet pipe 18a and the refrigerant outlet pipe 18b have similar lengths and sizes.

[0019] Also, the inner portion of refrigerant inlet pipe 18a and refrigerant outlet pipe 18b bent into an inverted U shape serves as freezing tank crossing section 19. When ice slurry production apparatus 11 is installed so that refrigerator 14 is located outside freezing tank 12 (described later) and flake ice preparation section 15 is located inside freezing tank 12, a part of wall section 12a of freezing tank 12 enters freezing tank crossing section 19 of refrigerant inlet pipe 18a and refrigerant outlet pipe 18b.

[0020] Here, as the refrigerant inlet pipe 18a and the refrigerant outlet pipe 18b, for example, it is possible to adopt flexible pipes that can be bent directly by hand without using tools by a worker assembling the ice slurry production apparatus 11. In this case, it is also preferable to cover the flexible pipes with a heat insulating material.

[0021] In addition, although omitted in FIG. 1 to avoid complicating the illustration, ice slurry manufacturing apparatus 11 is provided with a system (first refrigerant passage 29A described later) for circulating a refrigerant (first refrigerant) by refrigerator 14, as well as a system (second refrigerant passage 29B described later) for circulating a different type of refrigerant (second refrigerant), as shown in FIG. 2 (FIGS. 2 and 3(a)).

[0022] 1, the flake ice making section 15 includes a cooling section 21, a rotation drive section 22 as a drive section, a sweeping section 23 as an ice separating section, etc. Among these, the cooling section 21 includes a disk section 26 as an ice making plate and a number of refrigerant pipes (U-shaped pipes 28, etc.).

[0023] Disk section 26 is formed from a metal plate having a rectangular (here, square) plate surface (ice-making surface) and a predetermined thickness, and is fixed to frame section 17 (described later). The size (dimension) of disk section 26 can be, for example, an outer shape of about 30 cm square and a plate thickness of about 30 mm. Here, disk section 26 is not limited to being rectangular, and may be circular.

[0024] In this embodiment, the upper surface (plate surface 26a) and the lower surface (plate surface 26b, FIG. 4) of the disk portion 26 are machined to be substantially flat and parallel to each other. Copper or a copper alloy, which has high thermal conductivity, is used as the material for the disk portion 26. In this embodiment, the disk portion 26 is formed by casting. The surface of the disk portion 26 is plated with a metal (such as chromium) having wear resistance. Here, in addition to copper or a copper alloy, aluminum, iron, stainless steel, or the like can also be used as the material for the disk portion 26.

[0025] A large number of refrigerant holes 27 are formed inside the disk portion 26, as shown by dashed lines in Fig. 3(a). The refrigerant holes 27 extend parallel to one another in a straight line, penetrating the disk portion 26. The cross-sectional shape of the refrigerant holes 27 is a perfect circle. These refrigerant holes 27 are formed by drilling (perforating) the material of the disk portion 26.

[0026] Additionally, a large number of refrigerant pipes such as U-tubes 28 are joined to the disc portion 26, and two refrigerant passages are formed by the internal refrigerant holes 27 in the disc portion 26 and the U-tubes 28. Hereinafter, one of the refrigerant passages will be referred to as the "first refrigerant passage" and this "first refrigerant passage" will be given the reference symbol 29A. Additionally, the other refrigerant passage will be referred to as the "second refrigerant passage" and this "second refrigerant passage" will be given the reference symbol 29B.

[0027] The first refrigerant and the second refrigerant flow in a serpentine manner in the first refrigerant passage 29A and the second refrigerant passage 29B, respectively. As the first refrigerant (refrigerant gas), R404A, R447, R448A, or the like (having an evaporation temperature of about -60°C to -45°C) can be used. In the first refrigerant passage 29A, as shown in Fig. 2, the refrigerator 14 imparts fluidity to the first refrigerant. In this case, the refrigerator 14 functions as a fluidity imparting means for the first refrigerant.

[0028] The second refrigerant is different from the first refrigerant and may be liquefied natural gas (having an evaporation temperature of about -162°C) or liquid nitrogen (having an evaporation temperature of about -196°C) which has a lower evaporation temperature than the first refrigerant. In the second refrigerant passage 29B, the second refrigerant is stored in a second refrigerant tank 20 formed airtight. When a second refrigerant valve 20a provided in the second refrigerant passage 29B is opened, the second refrigerant is given fluidity by the pressure of the second refrigerant vaporized in the second refrigerant tank 20 or in the flow path. In this case, the second refrigerant valve 20a functions as a fluidity imparting means for the second refrigerant.

[0029] Here, the second refrigerant valve 20a can be opened manually, for example, by an operator who produces the ice slurry. Also, without being limited thereto, for example, the second refrigerant valve 20a may be opened by an operator who produces the ice slurry operating a predetermined button. Furthermore, for example, a temperature sensor (not shown) may be installed in the freezing tank 12, and when the temperature sensor detects that the aqueous solution Ws cooled by the first refrigerant has reached a predetermined set temperature, the second refrigerant valve 20a may be opened (opened by automatic control).

[0030] As the second refrigerant tank 20, for example, a container having a vacuum insulation structure (a container having a double structure) can be adopted. Also, as the second refrigerant valve 20a, various general valve devices that can be used in the flow paths of liquefied natural gas, liquid nitrogen, etc. can be adopted. In this embodiment, the refrigerant is supplied to the disk portion 26 by switching between the first refrigerant and the second refrigerant, and the method of supplying the refrigerant will be described later.

[0031] 3(a), reference numerals 18a and 18b denote a refrigerant inlet pipe 18a and a refrigerant outlet pipe 18b in the first refrigerant passage 29A, and reference numerals 19a and 19b denote a refrigerant inlet pipe 19a and a refrigerant outlet pipe 19b in the second refrigerant passage 29B. As described above, the second refrigerant passage 29B is omitted in FIG 1, and the second refrigerant passage 29B is shown in FIG 2, FIG 3(a), and FIG 4.

[0032] 3(a), when the disk portion 26 is viewed in plan, the direction in which the refrigerant holes 27 extend (the vertical direction in the figure) is perpendicular to the direction in which the refrigerant inlet tube 18a (and 19a) and the refrigerant outlet tube 18b (and 19b) extend (the horizontal direction in the figure). As described above, the refrigerant pipes such as the U-shaped tube 28 are joined to the disk portion 26, and brazing or the like can be used as a means of joining.

[0033] In the disk portion 26, the first refrigerant passage 29A and the second refrigerant passage 29B are formed so as to overlap each other twice in the thickness direction of the disk portion 26, as shown typically in Fig. 4. Here, in Fig. 4, the first refrigerant passage 29A and the second refrigerant passage 29B in the disk portion 26 are distinguished by symbols. In Fig. 4, the first refrigerant passage 29A is represented by a symbol of a perfect circle, and the second refrigerant passage 29B is represented by a symbol of a perfect circle with an x ​​mark attached.

[0034] The relationship between the refrigerant holes 27 in the disk portion 26 and the refrigerant introduction pipes 18a and the refrigerant discharge pipes 18b connected to the disk portion 26 is not limited to the example shown in Fig. 3(a). For example, when the disk portion 26 is viewed in a plan view as shown in Fig. 3(b), the direction in which the first refrigerant passage 29A and the second refrigerant passage 29B extend (the vertical direction in the figure) may be the same as the direction in which the refrigerant introduction pipes 18a and the refrigerant discharge pipes 18b extend (the vertical direction in the figure).

[0035] When the first refrigerant or the second refrigerant flows through the disk portion 26, heat is removed from the disk portion 26, and the disk portion 26 is cooled. As described above, the evaporation temperature of the first refrigerant is about -60°C to -45°C, and the evaporation temperature of the first refrigerant is about -162°C or lower. Although the details will be described later, the freezing point of the aqueous solution as the brine is about -38°C. Therefore, when the aqueous solution comes into contact with the disk portion 26, the aqueous solution is flash-frozen in the disk portion 26 and becomes ice (hybrid ice).

[0036] 5, the above-mentioned sweeping section 23 includes a buff support 31, and a plurality of buffs 33 are attached to each buff support 31. The buffs 33 are arranged to face the plate surfaces 26a, 26b of the disk section 26 in the cooling section 21. Furthermore, in this embodiment, the buffs 33 are arranged to contact the plate surfaces 26a, 26b of the disk section 26 with an appropriately weak pressure (low surface pressure). The buffs 33 have a function (sweeping function) of sweeping ice exposed on the plate surfaces 26a, 26b of the disk section 26 and separating it from the disk section 26, as described below.

[0037] As the material or composition of the buff 33, various materials generally used for polishing and the like can be adopted. For example, as the material of the buff 33, urethane or other synthetic resin, metal, wool, etc. can be adopted. In addition, as the material of the buff 33, sponge, foam, brush, scrubbing brush (scrubbing brush), resin net, nonwoven fabric, etc. using the above-mentioned various materials can be exemplified. In addition, the buff 33 may be a metal blade or the like provided with a predetermined amount of clearance (gap) (for example, about 0.2 mm) from the plate surfaces 26a, 26b of the disk portion 26.

[0038] Each buff 33 is attached to a rod-shaped spoke 34 provided on the buff support 31. Four spokes 34 of the buff support 31 are arranged at 90 degree intervals so as to face each plate surface 26a, 26b of the disk portion 26. The buff support 31 is integrally connected to a rotation transmission shaft 35 in the form of a round rod.

[0039] The rotation transmission shaft 35 penetrates the disk portion 26 in the thickness direction, avoiding the refrigerant hole 27, and is capable of rotating in forward and reverse directions about its axis. The rotation transmission shaft 35 is capable of rotational displacement together with the buff 33 relative to the stationary disk portion 26.

[0040] In this embodiment, as shown in FIG. 1, each buff 33 has a blade-like (elliptical) shape, and the buffs 33 are arranged in a four-blade propeller shape and face the plate surfaces 26a, 26b of the disk portion 26.

[0041] The sweeping unit 23 is connected to the rotary drive unit 22 (FIG. 1) via a rotation transmission shaft 35. The sweeping unit 23 is preferably rotated at a rotation speed of, for example, 10 to 100 rpm (revolutions per minute). A motor (buff drive motor) is incorporated in the rotary drive unit 22, and the rotary drive unit 22 is capable of continuously (or intermittently) rotating the sweeping unit 23 in the aqueous solution Ws (the liquid surface is shown imaginarily by a two-dot chain line in FIG. 1) stored in the freezing tank 12.

[0042] Here, the rotation drive unit 22 can be a geared motor that is an integral combination of a motor and a reduction gear (gear). The rotation drive unit 22 is located above the liquid surface of the aqueous solution Ws and is disposed so as to go outside the aqueous solution Ws. The rotation drive unit 22 is not limited to a unit that rotates the sweeping unit 23 in one direction, but may be a unit that rotates and reciprocates the sweeping unit 23 (a unit that rotates and reciprocates in the forward and reverse directions).

[0043] The arrangement of the buffs 33 is not limited to that shown in Fig. 1 or 5, and various other arrangements may be adopted. For example, the number of buffs 33 on each of the plate surfaces 26a, 26b of the disk portion 26 may be less than four or may be five or more.

[0044] Next, as shown in Fig. 1, the above-mentioned frame portion 17 is formed by, for example, connecting rod-shaped parts to form a framework. As the material of the frame portion 17, general angle material, round pipes, square pipes, extrusion materials, etc. can be adopted. In Fig. 1, the parts of the frame portion 17 are drawn as strips to avoid cluttering the drawing, but it is desirable to select the material taking into consideration the required strength and structure.

[0045] The components of the frame portion 17 can be joined by welding, screw fastening (including bolt fastening), etc. Also, metal or synthetic resin can be used as the material of the frame portion 17, and among these, various common metals such as steel, stainless steel, aluminum, etc. can be used as the metal. Furthermore, when using metals such as steel, various common surface treatments can be performed in consideration of rust prevention.

[0046] The freezer 14 and the flake ice producing unit 15 are fixed to the frame unit 17, and the frame unit 17 supports the freezer 14 and the flake ice producing unit 15. The freezer 14 and the flake ice producing unit 15 can be fixed to the frame unit 17 by a general means such as bolts or screws. The frame unit 17 also supports the flake ice producing unit 15 so that the rotation drive unit 22 of the flake ice producing unit 15 is outside the aqueous solution Ws.

[0047] When ice slurry production apparatus 11 is placed on the floor or the like, refrigerator 14 is placed on the floor, sandwiching a part of frame section 17 located below. In contrast, flake ice production section 15 is supported at a position horizontally offset by a specified amount from refrigerator 14 and at a position slightly higher than refrigerator 14.

[0048] And, between the freezer 14 and the flake ice making section 15, the freezing tank spanning section 19 of the refrigerant inlet pipe 18a and the refrigerant outlet pipe 18b are positioned in an open downward state. Here, in Fig. 1, a part of the frame section 17 and the freezing tank 12 are drawn as if they were cut out as shown by the two-dot chain line.

[0049] The height from the lower end to the upper end of ice slurry production apparatus 11 can be about 80 to 90 cm. Furthermore, the lower end of ice slurry production apparatus 11 can be the part of frame section 17 that contacts the floor surface, and the upper end of ice slurry production apparatus 11 can be the upper end of rotation drive section 22. By setting the height dimension of ice slurry production apparatus 11 to about 80 cm, the height of freezing tank 12, which will be described later, becomes a height that is easy for an operator performing the freezing work to work at.

[0050] Next, the freezing tank 12 and the aqueous solution Ws stored in the freezing tank 12 will be described. In this embodiment, the freezing tank 12 is formed in a rectangular container shape and has an open top. Although not shown in Fig. 1, the freezing tank 12 is surrounded by a thermal insulation material. Various general thermal insulation materials can be used here.

[0051] Also, each wall (including the bottom wall) of freezing tank 12 may have a built-in insulating material, may be hollow, etc. And, if sufficient insulation can be obtained by each wall of freezing tank 12 alone, the insulating material around freezing tank 12 may be omitted as appropriate.

[0052] The aqueous solution Ws shown by the two-dot chain line in Fig. 1 is the original solution for the ice slurry (also called brine). In this embodiment, an aqueous solution of ethanol with a predetermined concentration (here, 50 wt%) is used as the aqueous solution Ws. The amount of the aqueous solution Ws can be, for example, about 200 L (liters).

[0053] Most of the flake ice preparation section 15 of ice slurry production apparatus 11 is located inside freezing tank 12. In other words, freezer 14 of ice slurry production apparatus 11 is located outside freezing tank 12 and faces wall section 12a at one end in the longitudinal direction of freezing tank 12 from the outside.

[0054] On the other hand, flake ice producing section 15 is located inside wall section 12a, and the part from the bottom to about the middle height is immersed in a predetermined amount of aqueous solution Ws stored in freezing tank 12. Disk section 26 is disposed at the bottom of flake ice producing section 15, and when flake ice producing section 15 is immersed in aqueous solution Ws, the entire disk section 26 is also immersed in aqueous solution Ws.

[0055] Next, the function of the aqueous solution pump 13 will be described. The aqueous solution pump 13 pumps up the aqueous solution Ws as shown by the two-dot chain arrow A1 in Fig. 1, and guides the aqueous solution Ws to the freezing tank 12 as shown by the arrow A2. The aqueous solution pump 13 then sprays the aqueous solution Ws toward the disk section 26 of the flake ice preparation section 15. Here, in Fig. 1, the route of the aqueous solution is shown by the arrows A1 and A2, and piping is not shown.

[0056] Additionally, while various common pumps can be used as the aqueous solution pump 13, it is considered to select the aqueous solution pump 13 taking into consideration the mixing of solids (flake ice in this case) with the aqueous solution Ws. Also, passing the aqueous solution Ws mixed with flake ice through the piping or the aqueous solution pump 13 can have the effect of preventing clogging of the flow path. However, if it is not desired to pass flake ice through the aqueous solution pump 13, it is also considered to place a filter at the inlet of the piping or upstream of the aqueous solution pump 13 in order to remove flake ice and foreign matter from the aqueous solution Ws.

[0057] The aqueous solution Ws delivered by the aqueous solution pump 13 is sprayed from the nozzle portion 41 as shown in Fig. 5. The nozzle portion 41 is immersed in the aqueous solution Ws stored in the freezing tank 12, and the aqueous solution Ws (indicated by arrow A3 here) sprayed from the nozzle portion 41 forms a water flow by drawing in the aqueous solution Ws in the freezing tank 12. The aqueous solution Ws (arrow A3) sprayed from the nozzle portion 41 generates a flow velocity in the aqueous solution Ws stored in the freezing tank 12 and imparts momentum to the aqueous solution Ws. In other words, the aqueous solution pump 13, the nozzle portion 41, etc. constitute a water flow generating mechanism (propulsion mechanism) as a flow forming portion that forms the flow of the aqueous solution Ws.

[0058] Various general nozzles can be used as the nozzle portion 41. Examples of the nozzle portion 41 include a nozzle that ejects the aqueous solution Ws in a cone shape as indicated by an arrow A3, and a nozzle that ejects the aqueous solution Ws in a linear shape (not shown).

[0059] Nozzle portion 41 is immersed in aqueous solution Ws so as to generate a water flow around disk portion 26 in flake ice producing portion 15. The water flow generated by the aqueous solution discharged from nozzle portion 41 circulates between walls 12a, 12b located at the ends of freezing tank 12 in the length direction (longitudinal direction, left-right direction in FIG. 1).

[0060] As described above, the disk portion 26 is cooled by the cold energy of the refrigerant from the refrigerator 14, and therefore the aqueous solution Ws flowing around the disk portion 26 is cooled by the disk portion 26. Then, by sufficiently cooling the disk portion 26, the conditions are met, and ice precipitates on the plate surfaces 26a, 26b, etc. of the disk portion 26, and fine ice adheres to the periphery of the disk portion 26.

[0061] The ice that has surfaced and adhered in this way is swept away and separated from the disk portion 26 by the continuous rotation of the buff 33 of the sweeping portion 23, which collides with the adhered ice, as shown by the arrow A4 in Fig. 5 (sweeping function). As the sweeping portion 23 rotates, the buff 33 passes by a certain location intermittently, and the ice is separated from the disk portion 26 before it can grow large.

[0062] The ice separated from each plate surface 26a, 26b of the disk portion 26 becomes flake ice, which is caught up in the flow of the aqueous solution Ws (indicated by arrow A5) and blown away, cooling the aqueous solution Ws to the freezing point of the aqueous solution Ws.

[0063] By continuing the adhesion of ice and sweeping off the ice as described above while imparting fluidity to the aqueous solution Ws, the amount of flake ice in the aqueous solution Ws gradually increases, and an ice slurry is produced. The product to be frozen can be frozen, for example, by placing the product in a metal basket indicated by reference numeral 45 in Fig. 1 and having an operator hold the basket 45 and immerse it in the ice slurry.

[0064] It is also possible to integrally assemble and fix the water flow generating mechanism, such as the aqueous solution pump 13 and the nozzle unit 41, to the frame unit 17. In this case, the water flow generating mechanism can be provided integrally with the ice slurry producing apparatus 11. Also, for example, the aqueous solution pump 13 may be installed at a position away from the frame unit 17, and only the nozzle unit 41 and the piping connected to the nozzle unit 41 may be fixed to the frame unit 17. When the aqueous solution pump 13 is installed at a position away from the frame unit 17, the weight of the frame unit 17, including the various devices it supports, can be reduced.

[0065] It is also possible to integrally assemble and fix the water flow generating mechanism, such as the aqueous solution pump 13 and the nozzle unit 41, to the frame unit 17. In this case, the water flow generating mechanism can be provided integrally with the ice slurry producing apparatus 11. Furthermore, for example, the aqueous solution pump 13 may be installed at a position away from the frame unit 17, and only the nozzle unit 41 and the piping connected to the nozzle unit 41 may be fixed to the frame unit 17. When the aqueous solution pump 13 is installed at a position away from the frame unit 17, the weight of the frame unit 17, including the various devices it supports, can be reduced.

[0066] Next, Fig. 6(a) shows a schematic diagram of the buff 33 separating ice from the disk portion 26. The buff 33 attached to the spoke 34 moves horizontally (rotationally) from left to right in the figure as indicated by the two-dot chain arrow C. In the example of Fig. 6(a), the buff 33 is in contact with the upper plate surface 26a of the disk portion 26 with a moderately weak pressure (low surface pressure). The buff 33 is made of a material with a certain degree of flexibility, and has a rectangular (here, nearly square) cross-sectional shape.

[0067] 6(a), the buff 33 moves while in contact with the plate surface 26a of the disk portion 26, generating friction and deforming the cross-sectional shape into a parallelogram. The buff 33 strikes ice (not shown) formed on the plate surface 26a of the disk portion 26 to apply an external force to the ice, which is then swept off the plate surface 26a of the disk portion 26. Furthermore, the buff 33 sweeps off ice on the opposite surface of the disk portion 26 (the lower plate surface 26b) by the same principle.

[0068] In the example of Fig. 6(a), in explaining the principle of sweeping by the buff 33, the cross-sectional shape of the buff 33 and the cross-sectional shape of the spokes 34 are both rectangular. However, this is not limiting, and for example, in addition to a square bar, a round bar or other shapes can be used as the spokes 34. Furthermore, the cross-sectional shape of the buff 33 can also be a shape other than a rectangle, and examples of shapes other than a rectangle include a triangular shape, a polygonal shape, a perfect circle, and an elliptical shape.

[0069] Furthermore, not only the cross-sectional shape of each buff but also the planar shape thereof may be various shapes other than the blade shape. Although not shown in the drawings, the planar shape of the buff 33 may be a circular plate shape with a diameter of about 30 cm, and the number of buffs 33 may be one on each side of the disk portion 26, and this buff 33 may rotate horizontally around its center. Furthermore, it is also possible to make the outer diameter of the buff 33 smaller than about 30 cm, and to rotate one or more buffs 33 while rotating.

[0070] As a further modified example, it is possible to transmit power to a buff (not shown) from the side (side of the end) of the disk unit 26 without drilling a hole in the disk unit 26 through which the rotation transmission shaft 35 passes. In this case, for example, it is conceivable to use a parallel crank mechanism and cause links (arms) of the parallel crank mechanism to reciprocate with the disk unit 26 sandwiched between them. By employing such a mechanism, the sweeping unit 23 can be configured to sandwich the disk unit 26 and operate like a car windshield wiper to sweep away ice.

[0071] Also, a predetermined gap (for example, 1 mm or less to several mm) may be provided between the buff 33 and each of the plate surfaces 26a, 26b of the disk portion 26, and ice that has grown to a size larger than the gap may be swept away.

[0072] The buff 33 can be fixed to the spokes 34 by various general methods, such as adhesion, screw fastening (bolt fastening), riveting, clamping, and the like.

[0073] It is also possible to use a metal plate (metal blade, cutting teeth) 38 instead of the buff 33, as shown in FIG. 6(b). Furthermore, other than the metal plate 38, for example, a synthetic resin plate or the like can also be used. When using such a rigid body, it is possible to provide a gap H between the metal plate 38 and the disk portion 26, as shown in FIG. 6(b). In this way, wear of the metal plate 38 and the disk portion 26 can be prevented. The gap H can be, for example, about 1 mm or less (e.g., 0.2 mm).

[0074] Moreover, by moving the metal plate 38 etc. with a gap H, turbulent flow can be generated, for example, in front of and behind the metal plate 38 etc., as shown by multiple arrows D in Fig. 6(b). Although not shown, it is considered that turbulent flow can also be generated in the gap H between the metal plate 38 etc. and the disk portion 26. Even if the metal plate 38 etc. and the disk portion 26 are not in contact with each other, this turbulent flow can be used to separate ice from the disk portion 26. This turbulent flow is easily generated by moving the metal plate 38 etc. relatively quickly.

[0075] Here, the metal plate 38 and the like can be fixed to the spokes 34 in various general manners, such as by screw fastening (bolt fastening), riveting, clamping, welding, and the like.

[0076] The buff 33, the metal plate, etc. can be maintained by, for example, periodically replacing them.

[0077] Next, a method of supplying refrigerant to the disk unit 26 will be described. As described above, R404A or the like is used as the first refrigerant. The lower limit of the evaporation temperature setting of this R404A (evaporation temperature setting) is -60°C. In addition, when R447 or R448A is used as the refrigerant gas, setting the evaporation temperature to -60°C reduces the cooling efficiency, so the lower limit of the actual evaporation temperature setting is -45°C.

[0078] To efficiently produce a slurry (aqueous ethanol solution ice slurry) with a freezing point of -37°C or -50°C, or to produce an aqueous ethanol solution ice slurry at -80°C or lower, a refrigerant with a lower evaporation temperature should be used. Examples of refrigerants with lower evaporation temperatures include liquefied natural gas (evaporation temperature of about -162°C) and liquid nitrogen (evaporation temperature of about -196°C). However, liquefied natural gas and liquid nitrogen are relatively expensive, so it is desirable to use as little of them as possible in order to reduce costs.

[0079] Therefore, in this embodiment, a first refrigerant (e.g., −45° C.) is caused to flow through the first refrigerant passage 29A. The first refrigerant cools the disk portion 26, gradually lowering the temperature of the aqueous solution Ws (freezing point −38° C.). When the aqueous solution Ws reaches a predetermined set temperature (e.g., −30° C.), the supply of the first refrigerant by the refrigerator 14 is stopped.

[0080] Furthermore, the second refrigerant valve 20a (FIG. 2) is opened, and the second refrigerant (here, liquid nitrogen) flows in the second refrigerant passage 29B. The fluidity of the second refrigerant is provided by the pressure of the nitrogen gas vaporized in the second refrigerant tank 20. Then, the disk portion 26 is cooled by the second refrigerant, which has a significantly lower evaporation temperature than the first refrigerant, and the ice attached to the disk portion 26 is mixed into the aqueous solution Ws, producing an ice slurry at a temperature lower than −38° C.

[0081] That is, the first refrigerant is used for heat absorption (sensible heat absorption) related to the sensible heat portion from room temperature to -30°C, and the first cooling is performed. Furthermore, the refrigerant is switched, and for further cooling (cooling to which latent heat absorption is added), the cold energy of the second refrigerant is used to perform the second cooling. This second cooling produces low-temperature ice slurry. This makes it possible to perform cooling in multiple stages (two stages in this case), and to accelerate the cooling in the latter stages. This type of cooling method can be called, for example, a "two-stage cooling method" or a "two-stage rocket method."

[0082] Furthermore, since the relatively expensive liquid nitrogen (or liquefied natural gas, etc.) is used only for the secondary cooling, costs can be reduced compared to the case where liquid nitrogen, etc. is also used for cooling the sensible heat portion.

[0083] The present invention is not limited to a plate-shaped ice-making unit such as disk unit 26, but may employ a cylindrical ice-making unit (drum type) or ice-making units of various other shapes. For example, as a drum type, a cylindrical ice-making unit (drum 21 in Patent Document 2) as described in Patent Document 2 above may be provided in the cooling unit of this embodiment (corresponding to cooling unit 21 in FIG. 1), and this ice-making unit may be immersed in an aqueous solution (corresponding to aqueous solution Ws in FIG. 1). In this case, both the outer peripheral surface and the inner peripheral surface of the cylindrical ice-making unit are in contact with the aqueous solution.

[0084] Although not shown, the cylindrical ice making unit has a first refrigerant passage and a second refrigerant passage formed as separate systems. In the initial stage of cooling the aqueous solution, a first refrigerant (e.g., one with an evaporation temperature of about -60°C to -45°C) is caused to flow through the first refrigerant passage by a refrigerator (corresponding to refrigerator 14 in Fig. 1).

[0085] When the temperature of the aqueous solution reaches a predetermined set temperature (e.g., -30°C), the supply of the first refrigerant is stopped. Then, the second refrigerant valve (corresponding to the second refrigerant valve 20a in FIG. 2) is opened, and the second refrigerant (liquid nitrogen, etc.) is allowed to flow through the second refrigerant passage. The cylindrical ice-making unit is then cooled by the second refrigerant, which has a significantly lower evaporation temperature than the first refrigerant. In this way, the cylindrical ice-making unit can achieve high refrigeration capacity in two stages.

[0086] Furthermore, as another embodiment, it is possible to form a bottom in the cylindrical ice-making unit as described above, close the lower end, and fill (or store) the inside of the cylindrical ice-making unit with an aqueous solution, thereby using the cylindrical ice-making unit as a tank for the aqueous solution.

[0087] As another embodiment, a freezing tank equivalent to freezing tank 12 in Fig. 1 may be formed using metal, and a first refrigerant passage and a second refrigerant passage may be formed in the wall of the freezing tank. In this case as well, the first refrigerant may be caused to flow through the first refrigerant passage to cool the aqueous solution in the freezing tank, and after the temperature of the aqueous solution reaches a predetermined set temperature, the first refrigerant may be stopped and switched to the second refrigerant for further cooling.

[0088] Furthermore, the present invention is not limited to those that produce ice slurry by immersing the ice-making unit in an aqueous solution or storing the aqueous solution in the ice-making unit as described above, but can also be applied to ice-making devices that produce flake ice, such as the various ice-making units (ice-making devices) disclosed in Patent Documents 1 to 3 listed above.

[0089] In this case, a first refrigerant passage and a second refrigerant passage are also formed in the ice making unit. For example, a mist of aqueous solution (brine) is sprayed onto the ice making unit to bring the aqueous solution into contact with the ice making unit. The first refrigerant is caused to flow through the first refrigerant passage of the ice making unit to cool the aqueous solution in the freezing tank, and then the first refrigerant is stopped and switched to the second refrigerant for further cooling.

[0090] In addition, each embodiment is merely an example of a specific embodiment for carrying out the present invention, and the technical scope of the present invention should not be interpreted as being limited thereby. In other words, the present invention can be carried out in various forms without departing from the gist or main characteristics thereof. [Explanation of symbols]

[0091] 11 Ice slurry manufacturing equipment (ice making equipment) 14 Refrigeration Machine 20 Second refrigerant tank 20a Second refrigerant valve 26 Disk section (ice making section) 29A 1st refrigerant passage 29B 2nd refrigerant passage

Claims

1. an ice making section in contact with the brine; a first refrigerant passage formed to pass through the ice making unit and capable of allowing a first refrigerant to flow; a second refrigerant passage formed to pass through the ice making unit and capable of flowing a second refrigerant having a lower evaporation temperature than the first refrigerant; An ice making device, comprising: a cooling unit for cooling the ice making section, cooled by the first refrigerant, by the second refrigerant.

2. The ice making device according to claim 1 , wherein the ice making section is immersed in the brine.

3. 3. The ice making device according to claim 1, wherein the second refrigerant is given fluidity by a pressure of the vaporized second refrigerant.

4. An ice-making method comprising: passing a first refrigerant through an ice-making unit in contact with brine to cool the ice-making unit; switching to a second refrigerant having a lower evaporation temperature than the first refrigerant; and cooling the ice-making unit cooled by the first refrigerant with the second refrigerant.

5. an ice making section in contact with the brine; a first refrigerant passage formed to pass through the ice making unit and capable of allowing a first refrigerant to flow; a second refrigerant passage formed to pass through the ice making unit and capable of flowing a second refrigerant having a lower evaporation temperature than the first refrigerant, An ice-making method comprising the steps of: cooling the ice-making section with the first refrigerant and then cooling the ice-making section with the second refrigerant.

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