Refrigeration equipment

Abstract

To provide a liquid immersion type refrigeration system that can prevent evaporation of the coolant from the liquid surface. [Solution] The refrigeration apparatus of the present disclosure is a refrigeration apparatus that freezes an object by immersing the object in a coolant. The refrigeration apparatus comprises a cooling tank having an upper opening and storing the coolant inside, and a refrigerant pipe arranged on the outer circumference of the cooling tank and through which a refrigerant flows. The refrigerant pipe includes an upper refrigerant pipe that includes a portion located above the liquid surface of the coolant, and a lower refrigerant pipe located below the upper refrigerant pipe. The temperature around the upper refrigerant pipe is lower than the temperature around the lower refrigerant pipe.

Description

Technical Field

[0001] The present disclosure relates to a refrigeration device.

Background Art

[0002] In the freezer of a household refrigerator, when rapidly freezing food ingredients, the cooling method by cold air (air-cooling method) was the mainstream. On the other hand, a liquid immersion type refrigeration device with a faster cooling speed than the air-cooling method is known (for example, Patent Document 1). In the liquid immersion type refrigeration device, an object such as food is frozen by immersing the object in a coolant (a non-freezing liquid such as an ethanol solution).

[0003] In a large-scale industrial liquid immersion type refrigeration device, a forced circulation type in which the coolant is passed through a cooling section (evaporator) is mainly adopted. On the other hand, a direct cooling type cooling device is also known. In the direct cooling type cooling device, by arranging a refrigerant pipe (evaporator) along the outer peripheral surface of the cooling tank, the entire inner surface of the cooling tank becomes a cooling plate, and the coolant in the cooling tank is cooled. In the case of a direct cooling type cooling device, the cooling efficiency is higher for a small-sized device with a larger cooling area for the coolant than for a large-sized device with a smaller cooling area with respect to the amount of the coolant. For this reason, the direct cooling type cooling device is more suitable for small-sized devices for household use or small-scale applications than for large-scale devices for industrial use or the like.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In a liquid-immersion type refrigeration system using a coolant, when the lid of the cooling tank is open, the temperature in the space above the liquid level in the cooling tank is likely to rise due to the intrusion of outside air, potentially causing the coolant to evaporate. In particular, when the refrigeration system is started from a stopped state and before the inside of the cooling tank is sufficiently cooled, the coolant is more likely to evaporate when the lid is open. As a result, a concentration gradient may be created in the coolant within the cooling tank, potentially leading to uneven cooling capacity. Furthermore, if the coolant contains an organic solvent, there are concerns about flammability and potential health risks, so it is desirable to suppress the evaporation of the organic solvent as much as possible.

[0006] The object of this disclosure is to provide a liquid immersion type refrigeration system that can prevent evaporation of the coolant from the liquid surface. [Means for solving the problem]

[0007] One aspect of the present disclosure is a refrigeration device that freezes an object by immersing it in a cooling liquid. The refrigeration equipment is A cooling tank having an upper opening and storing the cooling liquid inside, The cooling tank is equipped with refrigerant pipes arranged on the outer circumference through which refrigerant flows. The refrigerant pipe includes an upper refrigerant pipe that includes a portion positioned above the liquid level of the coolant, and a lower refrigerant pipe positioned below the upper refrigerant pipe. The temperature around the upper refrigerant pipe is lower than the temperature around the lower refrigerant pipe. [Effects of the Invention]

[0008] According to one aspect of this disclosure, it is possible to provide a liquid immersion type refrigeration system that can prevent evaporation of the coolant from the liquid surface. [Brief explanation of the drawing]

[0009] [Figure 1] This is a schematic cross-sectional view showing a refrigeration system according to Embodiment 1. [Figure 2] This is a schematic cross-sectional view showing a refrigeration system according to Embodiment 2. [Modes for carrying out the invention]

[0010] The embodiments of this disclosure will be described below with reference to the drawings. In the following description, identical parts are denoted by the same reference numerals. Their names and functions are basically the same.

[0011] <Cooling device> In the cooling device of this embodiment, the object is frozen by immersing it in a cooling liquid. In other words, the cooling device of this embodiment is a liquid immersion type refrigeration device (rapid freezer).

[0012] The objects are not particularly limited, but examples include packaged foods. Examples of packaged foods include packaged foods containing a predetermined amount of meat, fish, or processed products thereof.

[0013] Coolant is a cooled antifreeze (a liquid that does not freeze even when cooled to the target temperature). In this embodiment, an example of an antifreeze is a liquid containing an organic solvent. Such an antifreeze may be called an organic brine or the like. Examples of organic solvents include alcohols such as ethanol. Examples of coolants (antifreezes) include solutions of organic solvents (such as aqueous ethanol solutions). Another example of an antifreeze solution is the use of highly concentrated saline solution. Such antifreeze solutions are sometimes called salt brine.

[0014] The temperature of the coolant is not particularly limited, but it is preferable to set it to a temperature that allows for rapid freezing to maintain the freshness of food and other items (for example, within a range of approximately -40°C to -20°C).

[0015] Referring to Figure 1, the cooling device of this embodiment comprises a cooling tank 2 and a refrigerant pipe 4. The cooling tank 2 has an upper opening 2a, and a coolant 3 is stored therein. The cooling tank 2 is disposed in a space formed by a case 21 and a lid 22 made of a heat insulating material or the like.

[0016] The refrigerant pipe 4 is disposed on the outer periphery of the cooling tank 2. The refrigerant pipe 4 is preferably disposed so as to contact the outer peripheral surface of the cooling tank 2. For example, it is wound around the outer peripheral surface of the cooling tank 2 in the outer peripheral direction (see FIG. 1). Refrigerant flows inside the refrigerant pipe 4, and by evaporating and absorbing heat inside the refrigerant pipe 4, the coolant 3 inside the cooling tank 2 can be cooled through the wall surface of the cooling tank 2. That is, the cooling device of the present embodiment is a direct cooling type refrigeration device.

[0017] In the present embodiment, the refrigerant pipe 4 is a refrigerant pipe that serves as an evaporation portion of the refrigerant, that is, a refrigerant pipe that serves as an evaporator of the refrigeration cycle. In order to evaporate (vaporize) the refrigerant inside the refrigerant pipe 4 (evaporator), a throttle portion (not shown) is usually provided on the upstream side of the refrigerant pipe 4. The throttle portion is composed of, for example, an expansion valve or a capillary tube. Normally, a compressor is connected downstream of the refrigerant pipe 4, and a condenser is connected downstream of the compressor. The throttle portion is connected downstream of the condenser. That is, the throttle portion is supplied with the refrigerant that has been compressed by the compressor and has released heat by condensing in the condenser. The refrigerant vaporized inside the refrigerant pipe 4 (evaporator) is returned to the compressor. In this way, a refrigeration cycle for cooling the cooling tank 2 is configured.

[0018] In the present embodiment, the refrigerant pipe 4 includes an upper refrigerant pipe 42 and a lower refrigerant pipe 41.

[0019] The upper refrigerant pipe 42 includes a portion disposed above the liquid level 3a of the coolant 3. That is, the entire upper refrigerant pipe 42 may be disposed above the liquid level 3a of the coolant 3, or a part of the upper refrigerant pipe 42 may be disposed above the liquid level 3a of the coolant 3, and another part may be disposed below the liquid level 3a of the coolant 3.

[0020] The lower refrigerant pipe 41 is positioned below the upper refrigerant pipe 42. The entire lower refrigerant pipe 41 may be positioned below the liquid level 3a of the coolant 3, or a portion of the lower refrigerant pipe 41 may be positioned above the liquid level 3a of the coolant 3 and another portion below the liquid level 3a of the coolant 3. It is preferable that the entire lower refrigerant pipe 41 is positioned below the liquid level of the coolant.

[0021] Furthermore, the temperature around the upper refrigerant pipe is set lower than the temperature around the lower refrigerant pipe. For example, it is lower than the temperature around the lower refrigerant pipe for at least a predetermined period (for example, until the compressor starts up and the temperature of the refrigerant pipe 4 stabilizes). In addition, immediately after the compressor starts up, the flow of refrigerant through the lower refrigerant pipe may be restricted for a predetermined period of time or until the temperature around the upper refrigerant pipe reaches a predetermined temperature. This makes it possible to prioritize lowering the temperature in the space above the liquid level 3a.

[0022] In this embodiment, the upper refrigerant pipe 42 includes a portion positioned above the liquid surface 3a of the coolant 3, and the temperature around the upper refrigerant pipe is lower than the temperature around the lower refrigerant pipe. This allows the space above the liquid surface 3a to be cooled at a lower temperature than the coolant storage area, thereby efficiently suppressing the evaporation of the coolant 3 when the lid 22 is opened. For example, if an organic solvent such as ethanol is used in the coolant 3, the organic solvent may evaporate from the liquid surface 3a of the coolant 3, causing organic matter to evaporate into the atmosphere, or if the organic solvent is a flammable substance, there is a risk of ignition. In this embodiment, by making the space above the liquid surface 3a colder than the coolant 3, the coolant that has risen to the liquid surface 3a by convection can be recooled by the space above the liquid surface 3a and returned to the storage section without evaporation. In particular, immediately after starting the refrigeration system, the temperature of the coolant 3 is close to room temperature, so the space above the liquid surface 3a of the cooling tank 2 is filled with organic solvent vapor. In this state, the lid 22 is closed and the organic solvent vapor does not leak out to the outside. However, when the temperature of the coolant 3 drops to a temperature at which rapid freezing is possible, and the lid 22 is opened to rapidly freeze the object, there is a possibility that the accumulated organic solvent vapor will leak out to the outside. In this embodiment, the space above the liquid surface 3a is prioritized to lower the temperature first to promote the condensation of organic solvent vapor, and the reliquefaction of organic solvent vapor around the opening of the lid 22 is promoted, thereby reducing the concentration of organic solvent vapor around the opening of the lid 22.

[0023] Furthermore, when the coolant 3 is not sufficiently cooled, the upper part of the coolant 3 stored in the cooling tank 2 is preferentially cooled, creating a temperature difference between the upper and lower parts of the coolant 3, which promotes natural convection of the coolant 3 (see the thick arrow in Figure 1). This equalizes the temperature of the coolant in the cooling tank 2, thereby increasing the cooling efficiency.

[0024] Furthermore, for example, if a high-concentration saline solution is used as the coolant 3, the concentration of the saline solution may decrease as the coolant 3 absorbs moisture from the outside air near the liquid surface 3a of the coolant 3. However, in this embodiment, the coolant 3, which is cooled to a lower temperature, becomes less concentrated and has a higher freezing point due to the absorption of moisture near the liquid surface 3a, and freezes and precipitates as ice. Therefore, the ice-formed water can be easily removed (e.g., by scooping it out with a net). This suppresses the decrease in the concentration of the coolant 3 over time, maintains the refrigeration performance, and also suppresses the occurrence of problems caused by the remaining ice.

[0025] The following describes specific examples (Embodiments 1 and 2) of the configuration of the cooling device 1 for lowering the temperature around the upper refrigerant pipe 42 to a lower temperature around the lower refrigerant pipe 41.

[0026] [Embodiment 1] Figure 1 shows a refrigeration device according to Embodiment 1. In Embodiment 1, the refrigerant flows through the upper refrigerant pipe 42 and then through the lower refrigerant pipe 41 (see arrow in Figure 1).

[0027] As the refrigerant flows through the refrigerant pipe 4 while evaporating, the cooling performance is higher upstream of the refrigerant pipe 4 when the coolant 3 is not sufficiently cooled. Therefore, by positioning the upstream side of the refrigerant pipe 4 as the upper refrigerant pipe 42 above the cooling tank 2 and the downstream side of the refrigerant pipe 4 as the lower refrigerant pipe 41 below the cooling tank 2, the evaporation of the refrigerant flowing through the upper refrigerant pipe 42 can be prioritized over the evaporation of the refrigerant flowing through the lower refrigerant pipe 41. In other words, the temperature around the upper refrigerant pipe 42 can be made lower than the temperature around the lower refrigerant pipe 41.

[0028] In Figure 1, the lower refrigerant pipe 41 is arranged to wrap around the outer surface of the cooling tank 2, starting from the bottom and moving upward. That is, within the lower refrigerant pipe 41, the refrigerant flows from bottom to top. A compressor is a device that compresses gaseous refrigerant, and if liquid refrigerant (refrigerant liquid) or refrigerant oil flows into the compressor, it can cause malfunctions such as damage to valves and valve covers. For this reason, in direct-cooling refrigeration systems, to prevent refrigerant liquid or refrigerant oil from flowing directly into the compressor, the refrigerant pipe 4 is usually wound around the outer surface of the cooling tank 2 from bottom to top (so that the downstream side of the refrigerant pipe 4 is at the top). In this embodiment, for similar reasons, the lower refrigerant pipe 41 is wound around the outer surface of the cooling tank 2 from bottom to top.

[0029] In Figure 1, the upper refrigerant pipe 42 is arranged to wrap around the outer surface of the cooling tank 2 from the top downwards. However, the upper refrigerant pipe 42 only needs to be positioned above the lower refrigerant pipe 41, and may also be arranged to wrap around the outer surface of the cooling tank 2 from the bottom upwards. This is because the downstream side of the upper refrigerant pipe 42 is connected to the lower refrigerant pipe 41 and not directly connected to the compressor, so there is no need to consider the risk of refrigerant liquid flowing into the compressor.

[0030] An accumulator (gas-liquid separator) may be provided on the suction side (upstream side) of the compressor. The accumulator separates any refrigerant liquid or refrigerant oil that has not evaporated in the refrigerant pipe 4 (evaporator), preventing the liquid from being directly drawn into the compressor.

[0031] [Embodiment 2] Figure 2 shows a refrigeration device according to Embodiment 2. Referring to Figure 2, in Embodiment 2, the lower refrigerant pipe 41 and the upper refrigerant pipe 42 are connected to separate refrigeration cycles. That is, in Embodiment 2, two independent refrigeration cycles are configured, each including the upper refrigerant pipe 42 and the lower refrigerant pipe 41.

[0032] In the lower refrigerant pipe 41, the first refrigerant evaporates. Meanwhile, in the upper refrigerant pipe 42, the second refrigerant evaporates.

[0033] In this way, by making the lower refrigerant pipe 41 and the upper refrigerant pipe 42 separate refrigeration cycles, the cooling performance of the refrigerant flowing through the upper refrigerant pipe 42 does not depend on the cooling load of the lower refrigerant pipe 41 (the heat load state of the cooling tank 2). As a result, the temperature around the upper refrigerant pipe 42 can be made lower than the temperature around the lower refrigerant pipe 41 more reliably.

[0034] In this embodiment, the two refrigeration cycles are independent, but for example, a configuration in which a part of the evaporator of the refrigeration cycle on the lower refrigerant pipe 41 side exchanges heat with a part of the condenser of the refrigeration cycle on the upper refrigerant pipe 42 side, a so-called cascade cycle configuration, may also be used. Furthermore, the refrigerants used in the two refrigeration cycles may be different refrigerants with different boiling points.

[0035] In the cooling device of Embodiment 2, the temperature around the upper refrigerant pipe 42 can be more reliably lowered than the temperature around the lower refrigerant pipe 41 compared to Embodiment 1 (the temperature difference between the upper and lower parts can be increased). Therefore, evaporation of the coolant 3 from the liquid surface 3a can be suppressed even more efficiently. Furthermore, natural convection of the coolant 3 can be further promoted. Furthermore, the water absorbed by the coolant 3 becomes more likely to freeze near the liquid surface 3a of the coolant 3, making it easier to remove the water that has turned into ice more reliably.

[0036] [summary] A refrigeration apparatus (e.g., refrigeration apparatus 1) according to one aspect of the present disclosure is a refrigeration apparatus that freezes an object by immersing it in a coolant (e.g., coolant 3). The cooling device includes a cooling tank (e.g., cooling tank 2) having an upper opening (e.g., upper opening 2a) and storing the cooling liquid inside, The cooling tank is equipped with a refrigerant pipe (for example, a refrigerant pipe 4) arranged on its outer circumference through which the refrigerant flows. The refrigerant pipe includes an upper refrigerant pipe (e.g., upper cooling pipe 42) which includes a portion positioned above the liquid level of the coolant (e.g., liquid level 3a), and a lower refrigerant pipe (e.g., lower cooling pipe 41) which is positioned below the upper refrigerant pipe. The temperature around the upper refrigerant pipe is lower than the temperature around the lower refrigerant pipe.

[0037] In a refrigeration apparatus relating to one aspect of this disclosure, The refrigerant flows through the upper refrigerant pipe and then through the lower refrigerant pipe. Within the lower refrigerant pipe, the refrigerant flows from bottom to top.

[0038] In a refrigeration apparatus relating to one aspect of this disclosure, Cooling by the upper refrigerant pipe takes precedence over cooling by the lower refrigerant pipe.

[0039] The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of this disclosure is indicated by the claims rather than the foregoing description, and all modifications within the meaning and scope of the claims are intended to be included. Configurations obtained by combining the configurations of the different embodiments described herein are also included in the scope of this disclosure. [Explanation of Symbols]

[0040] 1. Refrigeration equipment 2 Cooling tank 2a Top opening 21 cases (insulation material) 22 Lid (insulating material) 3 Coolant 3a Liquid level 4 Refrigerant pipes 41 Lower refrigerant pipe 42 Upper refrigerant pipe 51 First aperture section 52 Second aperture section 6 Ice

Claims

1. A refrigeration device that freezes an object by immersing it in a cooling liquid, A cooling tank having an upper opening and storing the cooling liquid inside, The cooling tank is equipped with refrigerant pipes arranged on the outer circumference through which refrigerant flows, The refrigerant pipe includes an upper refrigerant pipe that includes a portion positioned above the liquid level of the coolant, and a lower refrigerant pipe positioned below the upper refrigerant pipe. A refrigeration system in which the temperature around the upper refrigerant pipe is lower than the temperature around the lower refrigerant pipe.

2. The refrigerant flows through the upper refrigerant pipe and then through the lower refrigerant pipe. The refrigeration apparatus according to claim 1, wherein in the lower refrigerant pipe, the refrigerant flows from bottom to top.

3. The refrigeration apparatus according to claim 1, wherein cooling by the upper refrigerant pipe takes precedence over cooling by the lower refrigerant pipe.

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