Freshness retaining device

Abstract

To provide a freshness retaining device capable of cooling and taking ethylene countermeasures without using electrical power to retain freshness of at least either fruits and vegetables or flowering plants.SOLUTION: A dry ice container 3 is provided inside a storage container 2. The dry ice container 3 accommodates dry ice 12, and transfers coldness of the dry ice 12 into the storage container 2. A carbon dioxide supply part 4 is provided that supplies carbon dioxide, generated by sublimation of the dry ice 12 in the dry ice container 3, into the storage container 2.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a freshness preservation device for preserving the freshness of at least one of fruits and vegetables and flowers. [Background technology]

[0002] As disclosed in Patent Document 1, there is a method for maintaining freshness in a storage container for storing fruits, vegetables, and flowers, in which carbon dioxide gas and ethylene gas generated by the fruits, vegetables, vegetables, and flowers are removed by an adsorbent. As shown in Patent Document 2, there is a freshness-maintaining packaging bag for fruits and vegetables that maintains freshness by controlling the internal water vapor pressure. Patent Document 3 discloses an optimum freshness control system for fruits and vegetables. This optimum freshness control system is equipped with a storage cabinet, a cold water spray device, an ozone gas cylinder, and an ethylene gas cylinder, and the temperature and humidity inside the storage cabinet are monitored by an environmental measurement sensor, and based on data accumulated in a database, a system control unit (configured using a personal computer) controls the spraying of cold water into the storage cabinet by the cold water spray device, the supply of ozone gas to the storage cabinet by the cylinder, and the supply of ethylene gas to the storage cabinet by the cylinder. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-186420 [Patent Document 2] Japanese Patent Application Laid-Open No. 2004-284654 [Patent Document 3] Japanese Patent Application Publication No. 2019-41601 Summary of the Invention [Problem to be solved by the invention]

[0004] After harvest, fresh produce and flowers are transported to other locations while being kept as cool as possible in refrigerated trucks, or stored in refrigerators after transport. However, if the product is not cooled during transport when being transferred, if there is no power supply for the refrigerator during storage, or if there is a discrepancy between the shipping date and the start of storage, the freshness of the harvested produce (fresh produce and flowers) can deteriorate, resulting in an estimated 10–20% of the harvest being discarded. This deterioration in freshness is thought to be due to two factors: 1) the inability to maintain the temperature optimal for maintaining freshness (generally, the optimum temperature for most harvests is around 4–10°C), and 2) the adverse effects of ethylene released by the harvested product itself. Many harvested species naturally release ethylene to ripen themselves to a state suitable for consumption by other animals. However, because they are unable to regulate their own ethylene release, they continue to release ethylene even after the appropriate level of ripening, resulting in excessive ripening. Furthermore, if a large amount of harvested produce is stored at the same time in a storage facility, the ethylene released by one harvested product will affect the other harvested products, and even species that do not emit ethylene will be adversely affected by ethylene.Furthermore, in addition to ethylene, methanol and acetaldehyde are also released during ripening, and it is said that harvested products will also be adversely affected by these components.

[0005] Even if the food is transported in a refrigerated refrigerator, refrigerated truck, or refrigerated delivery service, the food cannot be cooled during reloading, which affects freshness. In particular, during the summer, even just reloading can affect freshness. In addition, there is no atmospheric control inside the storage facility, which also affects freshness. Even if there is a refrigerator for cooling, if there is no power supply, or if there is no refrigerated truck or refrigerated delivery service available, the food will not be cooled and there will be no atmosphere control, which will affect freshness. Even if stored in a refrigerated refrigerator, freshness will be affected if the atmosphere is not controlled. There is a storage method called CA storage (Controlled Atmosphere Storage) that controls the atmosphere, temperature, and humidity (basically only for apples), but because it requires capital investment, it is cost-effective for large-scale storage facilities or when you want to maintain freshness for several months, but it is not cost-effective for small-scale storage facilities or when you want to maintain freshness for several weeks. The freshness preservation methods disclosed in Patent Documents 1 and 2 do not involve cooling the object to be freshened. The freshness preservation method disclosed in Patent Document 3 uses a personal computer, which requires electricity and is large-scale.

[0006] The present invention provides a freshness preservation device that maintains the freshness of at least one of fruits and vegetables and flowers by cooling and taking measures against ethylene without using electricity. [Means for solving the problem]

[0007] The present invention provides a freshness preservation device for preserving the freshness of at least one of fruits and vegetables and flowers, comprising: The storage system includes a storage container for storing at least one of fruits and vegetables and flowers, a dry ice container provided within the storage container for storing dry ice and radiating the cold heat of the stored dry ice into the container, and a carbon dioxide supply unit for supplying carbon dioxide generated by sublimation of the dry ice in the dry ice container into the container.

[0008] According to this configuration, the cold radiated by the dry ice contained in the dry ice container is transferred to the dry ice container, which then radiates the cold from the dry ice into the storage container, thereby cooling the inside of the storage container. By cooling the inside of the storage container, the harvested product (at least one of fruits, vegetables, and flowers) in the storage container can be cooled. Carbon dioxide generated by the sublimation of the dry ice is supplied into the storage container by the carbon dioxide supply unit, and the harvested product is stored in a carbon dioxide environment. By storing the harvested product in a carbon dioxide environment, the physiological activity of the harvested product decreases, and ethylene release from the harvested product can be suppressed. By suppressing ethylene release from the harvested product, the increase in ethylene in the storage container can be suppressed. In other words, by suppressing ethylene release from the harvested product and the increase in ethylene in the storage container, the adverse effects of ethylene on the harvested product can be suppressed. In other words, the harvested products can be cooled by the cold energy of the dry ice, and the adverse effects of ethylene on the harvested products can be suppressed by the carbon dioxide generated from the dry ice, so that the freshness of at least one of fruits, vegetables, and flowers can be maintained by cooling and taking measures against ethylene without using electricity. Furthermore, because no electricity is used, the size of the freshness preservation device does not need to be very large, and at least one of fruits, vegetables, and flowers can be stored and transported without a loss of freshness even without a power source.

[0009] In the present invention, The storage container is preferably provided with an outlet that allows carbon dioxide supplied into the container to flow out of the container.

[0010] According to this configuration, when carbon dioxide leaks out of the storage container, ethylene generated from the harvested crops also leaks out of the storage container together with the carbon dioxide, thereby reducing the high ethylene concentration in the storage container and suppressing the adverse effects of ethylene on at least one of the fruits and vegetables and flowers.

[0011] In the present invention, It is preferable that a concentration adjusting unit be provided that adjusts the concentration of carbon dioxide supplied into the container by the carbon dioxide supply unit.

[0012] According to this configuration, even if different types of fruit or the like are stored, the concentration of carbon dioxide in the storage container can be adjusted by the concentration adjusting unit to a concentration suitable for the fruit or the like being stored.

[0013] In the present invention, It is preferable that the concentration adjustment unit adjusts the concentration of carbon dioxide by introducing air from the outside into the carbon dioxide flow path in the carbon dioxide supply unit due to the flow of carbon dioxide flowing through the carbon dioxide flow path toward the inside of the container, and mixing the introduced air with the carbon dioxide.

[0014] According to this configuration, it is only necessary to provide the concentration adjusting section with a simple adjusting structure in which air is introduced from the outside to the inside of the carbon dioxide flow path by the flow of carbon dioxide, making it possible to adjust the concentration of carbon dioxide inexpensively.

[0015] In the present invention, It is preferable that the concentration adjustment unit is provided outside the storage container and has a venturi structure, and that the venturi structure is positioned over the outside of the carbon dioxide flow path and has an air introduction path that introduces air from the outside to the inside of the carbon dioxide flow path.

[0016] According to this configuration, the concentration adjusting section can be obtained with a simple structure by utilizing the venturi structure.

[0017] In the present invention, It is preferable that the dry ice container is provided with a relief valve for adjusting the internal pressure of the container to a set pressure or less.

[0018] According to this configuration, when the internal pressure of the dry ice container exceeds the set pressure set by the relief valve, the relief valve releases carbon dioxide from the dry ice container, thereby preventing the internal pressure of the dry ice container from rising too much.

[0019] In the present invention, It is preferable that the carbon dioxide supply unit introduces carbon dioxide discharged by the relief valve and supplies the introduced carbon dioxide into the container.

[0020] According to this configuration, carbon dioxide is supplied to the storage container by the flow pressure discharged from the relief valve, and carbon dioxide is smoothly supplied to the storage container. By smoothly supplying carbon dioxide to the storage container, a stable carbon dioxide environment in the storage container can be obtained so that a carbon dioxide shortage does not occur. [Brief explanation of the drawings]

[0021] [Figure 1] FIG. 1 is a schematic diagram of a freshness preservation device. [Figure 2] FIG. 2 is a cross-sectional plan view of the freshness preservation device. [Figure 3] FIG. 1 is an explanatory diagram of a venturi structure. [Figure 4] FIG. 1 is an explanatory diagram of optimal storage conditions for fruits that may be subject to freshness maintenance. [Figure 5] FIG. 10 is an explanatory diagram showing test results of peaches using a freshness preservation device. [Figure 6] FIG. 10 is an explanatory diagram showing test results of peaches using a freshness preservation device. [Figure 7] FIG. 1 is an explanatory diagram showing the measurement results of the amount of ethylene generated in a peach test. [Figure 8] FIG. 1 is an explanatory diagram showing the measurement results of the amount of methanol generated in a peach test. [Figure 9] FIG. 1 is an explanatory diagram showing the measurement results of the amount of acetaldehyde generated in a peach test. [Figure 10] FIG. 10 is an explanatory diagram showing the measurement results of temperature and humidity in a storage container when dry ice was placed in the peach test. [Figure 11] FIG. 10 is an explanatory diagram showing the measurement results of the amount of CO2 generated when dry ice was added in a peach test. [Figure 12]FIG. 10 is an explanatory diagram showing test results of roses using a freshness preservation device. [Figure 13] FIG. 10 is an explanatory diagram showing test results of roses using a freshness preservation device. [Figure 14] FIG. 1 is an explanatory diagram showing the measurement results of the amount of ethylene generated in a rose test. [Figure 15] FIG. 1 is an explanatory diagram showing the measurement results of the amount of methanol generated in a rose test. [Figure 16] FIG. 1 is an explanatory diagram showing the measurement results of the amount of acetaldehyde generated in a rose test. [Figure 17] FIG. 10 is an explanatory diagram showing the measurement results of temperature and humidity in a storage container when dry ice was placed in the storage container in a loose sample test. [Figure 18] FIG. 10 is an explanatory diagram showing the measurement results of the amount of CO2 generated when dry ice was added in a rose test. DETAILED DESCRIPTION OF THE INVENTION

[0022] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will now be described with reference to the accompanying drawings. FIG. 1 is a schematic diagram of a freshness preservation device. The freshness preservation device maintains the freshness of fruits, vegetables, flowers, and ornamental plants. Fruits and vegetables include vegetables, fruits, wild plants, and mushrooms, such as strawberries, peaches, Shine Muscat grapes, and cherries. Ornamental plants include cut flowers, cut leaves, cut branches, and bulbs, and are cultivated for ornamental purposes. Examples include cut flowers such as roses, lilies, and chrysanthemums.

[0023] 1 and 2, freshness preservation device 1 includes storage container 2, dry ice container 3, and carbon dioxide supply unit 4. In the following description, fruits, vegetables, and flowers to be kept fresh will be referred to as harvested product 13.

[0024] As shown in FIGS. 1 and 2, the storage container 2 comprises a storage-container body 2a and a storage lid 2b. The storage lid 2b is connected to the storage-container body 2a via a hinge member 5 attached to one end of the storage lid 2b and is held to the storage-container body 2a so as to be swingable open and closed, opening and closing the internal space of the storage-container body 2a when swung around the hinge axis of the hinge member 5 as a swing fulcrum. The storage lid 2b is equipped with a snap lock (not shown) attached to the end of the storage lid 2b opposite the side where the hinge member 5 is located, and is configured to be closed and locked to the storage-container body 2a by the snap lock. In this embodiment, the storage lid 2b can be swung open and closed, but it may also be a storage lid that can be opened and closed by being detached from the storage-container body 2a. The storage-container body 2a and the storage lid 2b are made of thermally insulating materials, and the storage container 2 is an insulated container that prevents heat from radiating from the inside of the container to the outside. The storage container body 2a is provided with an outlet 6 that allows carbon dioxide and the like to flow out of the container from inside the container to outside. In this embodiment, the outlet 6 is provided in the storage container body 2a, but it can also be provided in the storage lid 2b.

[0025] 1, in the storage container 2, the harvest 13 is placed in the storage container body 2a and the storage lid 2b is closed and locked, thereby storing the harvest 13 inside the container. The harvest 13 is stored while making it difficult for the cold energy supplied into the container to dissipate outside the container, and allowing carbon dioxide and the like supplied into the container to flow out of the container through the outlet 6.

[0026] As shown in FIGS. 1 and 2, the dry ice container 3 is provided inside the storage container 2. The dry ice container 3 comprises a container body 3a and a container lid 3b. The container lid 3b is held by the container body 3a so that it can be opened and closed by swinging it open and closed, and can be locked closed. In this embodiment, the container lid 3b can be opened and closed by swinging it open and closed, but it may also be opened and closed by being detached from the container body 3a. The container body 3a and the container lid 3b are made of materials that can transfer the cold heat radiated by the dry ice contained inside the dry ice container 3 and can transfer the transferred cold heat into the storage container 2. The dry ice container 3 is a pressure vessel that allows the contained dry ice to sublimate, generating carbon dioxide and increasing the pressure inside the container.

[0027] In the dry ice container 3, the dry ice 12 is placed in the container body 3a and the container lid 3b is closed and locked, thereby storing the dry ice 12 inside the container. The dry ice 12 is stored while the cold heat of the dry ice 12 is transferred to the inside of the storage container 2 and while allowing the internal pressure of the container to increase due to carbon dioxide generated by the sublimation of the dry ice 12.

[0028] 1 and 2, the carbon dioxide supply unit 4 is provided outside the storage container 2. The carbon dioxide supply unit 4 is connected to the dry ice container 3 and the storage container 2, and is configured to supply carbon dioxide generated by sublimation of the dry ice 12 in the dry ice container 3 into the storage container 2. In this embodiment, the carbon dioxide supply unit 4 is a resin hose. The carbon dioxide supply unit 4 is not limited to a resin hose, and may be a resin pipe, a steel pipe, or the like.

[0029] In more detail, as shown in Figures 1 and 2, the carbon dioxide supply unit 4 is connected to the dry ice container 3 by providing a relief unit 7 on the dry ice container 3 and connecting the carbon dioxide supply unit 4 to a relief valve 8 provided on the relief unit 7.

[0030] 1 and 2, the relief section 7 includes a relief circuit 9 that extends from the dry ice container 3 and is pulled out to the outside of the storage container 2 by passing through the wall of the storage-container main body 2a, and a relief valve 8 that is connected to the relief circuit 9 outside the storage container 2. In this embodiment, the relief circuit 9 is a resin hose. In addition to the resin hose, the relief circuit 9 may also be a resin pipe, a steel pipe, or the like.

[0031] Relief valve 8 is configured to adjust the internal pressure of dry ice container 3 to a set pressure or less. That is, carbon dioxide generated by sublimation of dry ice 12 in dry ice container 3 flows into relief valve 8 via relief circuit 9, and when the internal pressure of dry ice container 3 is equal to or less than the relief pressure set by relief valve 8, relief valve 8 is maintained in a closed state to prevent carbon dioxide from flowing out of dry ice container 3. When the internal pressure of dry ice container 3 exceeds the relief pressure of relief valve 8, relief valve 8 is switched to an open state by the internal pressure of the container, and carbon dioxide in dry ice container 3 is discharged through relief valve 8.

[0032] The relief valve 8 is a variable relief valve. That is, the relief valve 8 is provided with a relief pressure adjuster 8a, and the relief pressure is changed and set by rotating the relief pressure adjuster 8a.

[0033] The carbon dioxide supply unit 4 introduces carbon dioxide discharged from the relief valve 8, and smoothly supplies carbon dioxide to the storage container 2 with the flow pressure discharged from the relief valve 8. This allows the harvested products to be stored in an environment where carbon dioxide is stably obtained so that carbon dioxide shortages do not occur.

[0034] The carbon dioxide supply unit 4 is connected to the storage container 2 by being connected to the storage lid 2b of the storage container 2. In this embodiment, the carbon dioxide supply unit 4 is connected to the storage lid 2b, but it can also be connected to the storage container main body 2a.

[0035] 1, the carbon dioxide supply unit 4 is provided with a concentration adjustment unit 10, and the concentration of carbon dioxide supplied to the storage container 2 is adjusted by the concentration adjustment unit 10. In this embodiment, the concentration adjustment unit 10 is provided in a portion of the carbon dioxide supply unit 4 that connects to the storage lid 2b. The concentration adjustment unit 10 can be provided in an intermediate portion of the carbon dioxide supply unit 4 that is located between the storage container 2 and the relief valve 8.

[0036] More specifically, the concentration adjusting unit 10 is provided outside the storage container 2 and has a venturi structure.

[0037] The venturi structure is configured as shown in Fig. 3. That is, the carbon dioxide flow path 11 in the carbon dioxide supply unit 4 is provided with an upstream flow path section 11a located on the upstream side and a downstream flow path section 11b located on the downstream side, which are separated from each other. The downstream flow path section 11b is provided with a large diameter section 11c that covers the outer periphery of the upstream flow path section 11a, and the air introduction path 10a that covers the outside of the carbon dioxide flow path 11 is formed by the large diameter section 11c. The air introduction path 10a is mainly formed by the gap between the inner diameter side of the large diameter section 11c and the outer diameter side of the upstream flow path section 11a.

[0038] In concentration adjusting unit 10, carbon dioxide flowing through carbon dioxide flow path 11 toward storage container 2 flows from upstream flow path section 11a toward downstream flow path section 11b. The flow of carbon dioxide flowing from upstream flow path section 11a toward downstream flow path section 11b applies suction force to air introduction path 10a, and air is introduced from the outside to the inside of carbon dioxide flow path 11 through air introduction path 10a, and the introduced air is mixed with the carbon dioxide flowing toward storage container 2.

[0039] In the concentration adjusting section 10, air is mixed into the carbon dioxide due to the ejector effect of the carbon dioxide flowing through the carbon dioxide flow path 11. The concentration of carbon dioxide is adjusted by adjusting the amount of air mixed in.

[0040] Freshness preservation device 1 can maintain the freshness of harvested product 13 without using electricity.

[0041] That is, by storing dry ice 12 in the dry ice container 3, the cold heat of the dry ice 12 is transferred into the storage container 2 via the dry ice container 3. That is, the harvested product 13 located inside the storage container 2 is stored while being cooled by the cold air of the dry ice 12 whose heat is transferred into the container.

[0042] Dry ice sublimes in dry ice container 3, generating carbon dioxide. The carbon dioxide generated in dry ice container 3 is supplied to storage container 2 by carbon dioxide supply unit 4, and harvest 13 placed in storage container 2 is placed in a carbon dioxide environment, whereby ethylene release from harvest 13 is suppressed by the carbon dioxide. By suppressing ethylene release from harvest 13, an increase in ethylene within storage container 2 can be suppressed, and harvest 13 is stored while suppressing the adverse effects of ethylene.

[0043] The carbon dioxide supplied to storage container 2 does not remain inside the container but flows out of the container through outlet 6, and the ethylene inside the container flows out of the container together with the carbon dioxide. By allowing ethylene to flow out of storage container 2, the ethylene concentration that has increased inside storage container 2 can be reduced, and harvested product 13 can be stored while suppressing the adverse effects of ethylene on the product.

[0044] Carbon dioxide generated in dry ice container 3 is discharged through relief valve 8 and introduced into carbon dioxide supply unit 4, whereby carbon dioxide is supplied to storage container 2 at a flow pressure corresponding to the relief pressure of relief valve 8. As a result, carbon dioxide is supplied to storage container 2 without shortage, and harvest 13 is stored in a carbon dioxide environment where there is an amount of carbon dioxide sufficient to suppress ethylene release from harvest 13.

[0045] Carbon dioxide is supplied to the storage container 2 after its concentration has been adjusted by the concentration adjustment unit 10, so that even if the type of harvest 13 is different, the harvest 13 is stored while the ethylene release from the harvest 13 is suppressed by carbon dioxide at a concentration suited to the harvest 13.

[0046] As shown in Figure 4, the optimum conditions for storing fruits that may be subject to freshness preservation are presented. Strawberries can be stored for four weeks at 5-10 percent CO2 and for seven to 10 days at 15-20 percent CO2. Peaches can be stored for four weeks at 7-9% CO2. Cherries can be stored at 20-25% CO2 for 2-3 weeks. The presentation of this information is Source:2001,University of California Postharvest Technology Source: 2022, Agricultural Products Distribution Technology Research Association Annual Report, Agricultural Products Longzhu Technology 2022, 106.

[0047] The test results of the freshness preservation device of the present invention are shown below. <Test on peaches> Test details: 1. Store the peaches in a Tupperware container (sealed). Test content 2. Store the peaches in a Tupperware container (not sealed, but partially open). Test content 3. Peaches and CO2 gas (10%) are stored in a Tupperware container (sealed). Test procedure 4: 2 kg of dry ice was placed in the dry ice container 3 and the peaches were stored in the storage container 2. Test procedure 4 corresponds to the freshness preservation device of the present invention. The Tupperware and storage container 2 are stored at room temperature. The Tupperware and storage container 2 are opened approximately every 1-2 days to check the condition of the peaches. They are then stored for 16 days. Dry ice and CO2 gas are added each time the storage container 2 is opened. FIG. 5 shows the sensory evaluation results after four days of storage. In tests 1, 2, and 3, the color became slightly darker, and in tests 1 and 2, the product became slightly softer. In test 4, there was no change in appearance or texture, and the product maintained its freshness. FIG. 6 shows the sensory evaluation results after 14 days of storage. In test items 1, 2, and 3, the fruit had turned black and the insides had spoiled. They had also become soft. In test item 4, the bottom had started to bruise a little, but the top was clean and still firm, maintaining its freshness. Figure 7 shows the measurement results of the amount of ethylene generated in the Tupperware or storage container 2, Figure 8 shows the measurement results of the amount of methanol generated in the Tupperware or storage container 2, and Figure 9 shows the measurement results of the amount of acetaldehyde generated in the Tupperware or storage container 2. The horizontal axis of Figures 7, 8, and 9 indicates the number of days elapsed since preparation, and the vertical axis indicates the concentration of the evolved gas. In Figures 7, 8, and 9, the black circles indicate the results of Test 1, the crosses indicate the results of Test 3, and the white circles indicate the results of Test 4. It can be seen that the peaches in test item 4 had a low concentration of ethylene inside the container. In other words, the freshness preservation device of the present invention can effectively take measures against ethylene. FIG. 10 shows the measurement results of the temperature and humidity inside the storage container 2 in Test Content 4. 10, the horizontal axis represents elapsed time, and the vertical axis represents temperature (° C.) and humidity (%). In FIG. 10, the dashed line represents temperature, and the solid line represents humidity. Figure 11 shows the measurement results of the CO2 concentration in the storage container 2 in Test 4. The horizontal axis of Figure 11 shows the elapsed time, and the vertical axis shows the CO2 concentration (ppm). The CO2 concentration was maintained at around 10%.

[0048] <Tests on roses> Test procedure 1: 2 kg of dry ice was placed in the dry ice container 3 and the loose fruit was stored in the storage container 2. Test procedure 1 corresponds to the freshness preservation device of the present invention. Test content 2. Store the roses and CO2 (10%) in a Tupperware container (sealed, 20°C). Test content 3. Store the roses in a Tupperware container (sealed, 20°C). Test content 4. Store the roses in a Tupperware container (partially open, 20°C). The Tupperware and storage container 2 were opened approximately every two days to check the condition of the roses. They were stored for a total of six days. Dry ice and CO2 gas were added each time storage container 2 was opened. FIG. 12 shows the sensory evaluation results after 3 days of storage. In test items 2, 3, and 4, the fruit turned brown and withered. In test item 1, there was almost no change in appearance and the fruit maintained its freshness. Figure 13 shows the sensory evaluation results after 6 days of storage. The withering in test item 1 was less severe than in tests 2, 3, and 4, and the freshness was maintained. Figure 14 shows the measurement results of the amount of ethylene generated in the Tupperware or storage container 2, Figure 15 shows the measurement results of the amount of methanol generated in the Tupperware or storage container 2, and Figure 16 shows the measurement results of the amount of acetaldehyde generated in the Tupperware or storage container 2. The horizontal axis of Figures 14, 15, and 16 indicates the number of days elapsed since preparation, and the vertical axis indicates the concentration of the evolved gas. In Figures 14, 15, and 16, the black circles indicate the results of Test 3, the cross marks indicate the results of Test 2, and the white circles indicate the results of Test 1. It can be seen that the ethylene concentration in the container of the loose fruit in Test 1 is low. In other words, the freshness preservation device of the present invention can effectively deal with ethylene. FIG. 17 shows the measurement results of the temperature and humidity inside the storage container 2 in Test Content 1. 17, the horizontal axis represents elapsed time, and the vertical axis represents temperature (° C.) and humidity (%). In FIG. 17, the dashed line represents temperature, and the solid line represents humidity. Figure 18 shows the measurement results of the CO2 concentration inside the storage container 2 in Test Content 1. The horizontal axis of Figure 18 shows the elapsed time, and the vertical axis shows the CO2 concentration (ppm). The CO2 concentration was maintained at around 10%.

[0049] [Another embodiment] (1) In the above-described embodiment, both fruits and vegetables and flowers are the objects to be kept fresh. However, it is also possible to keep freshness of at least one of fruits and vegetables and flowers.

[0050] (2) In the above-described embodiment, an example in which the outlet 6 is provided is shown, but this is not limiting. It is also possible to have no outlet 6, and instead detect the internal pressure of the storage container 2 and adjust the supply of carbon dioxide to the storage container 2 so that too much carbon dioxide does not accumulate in the storage container 2.

[0051] (3) In the above embodiment, an example was shown in which the concentration adjusting unit 10 was provided, but the concentration adjusting unit 10 may not be provided.

[0052] (4) In the above embodiment, the concentration adjustment unit 10 is configured to introduce air by utilizing the flow of carbon dioxide, but the concentration adjustment unit 10 may also introduce air without utilizing the flow of carbon dioxide.

[0053] (5) In the above embodiment, an example was shown in which the carbon dioxide discharged by the relief valve 8 is supplied to the storage container 2 by the carbon dioxide supply unit 4. However, the carbon dioxide supply unit 4 may be configured to introduce carbon dioxide from the dry ice container 3 without going through this relief valve, by providing a dedicated relief valve that adjusts the internal pressure of the dry ice container 3 to a set pressure or less.

[0054] Furthermore, the configurations disclosed in the above embodiments (including other embodiments, the same applies below) can be applied in combination with configurations disclosed in other embodiments, as long as no contradiction arises. Furthermore, the embodiments disclosed in this specification are examples, and the embodiments of the present invention are not limited to these, and can be modified as appropriate within the scope that does not deviate from the purpose of the present invention. [Industrial Applicability]

[0055] The present invention can be applied to a freshness preservation device for preserving the freshness of at least one of fruits and vegetables and flowers. [Explanation of symbols]

[0056] 2. Storage container 3 dry ice containers 4 Carbon dioxide supply unit 6 Outlet 8 Relief valve 10 Density adjustment section 10a Air intake passage 11 Carbon dioxide flow path 12. Dry ice

Claims

1. A freshness preservation device for preserving the freshness of at least one of fruits and vegetables and flowers, a storage container for storing at least one of fruits and vegetables and flowers; a dry ice container provided in the storage container, for storing dry ice and radiating cold heat from the stored dry ice into the container; a carbon dioxide supply unit that supplies carbon dioxide generated by sublimation of dry ice in the dry ice container into the container; A freshness-maintaining device is provided.

2. 2. The freshness preservation device according to claim 1, wherein the storage container is provided with an outlet that allows carbon dioxide supplied into the container to flow out of the container.

3. 2. The freshness preservation device according to claim 1, further comprising a concentration adjusting unit that adjusts the concentration of carbon dioxide supplied into the container by the carbon dioxide supply unit.

4. The freshness preservation device of claim 3, wherein the concentration adjustment unit adjusts the concentration of carbon dioxide by introducing air from the outside into the carbon dioxide flow path in the carbon dioxide supply unit through the carbon dioxide flow path toward the container, and mixing the introduced air with the carbon dioxide.

5. the concentration adjusting unit is provided outside the storage container and has a venturi structure, 5. The freshness-preserving device according to claim 4, wherein the venturi structure is positioned so as to cover the outside of the carbon dioxide flow path and includes an air inlet path for introducing air from the outside of the carbon dioxide flow path to the inside.

6. 2. The freshness-preserving device according to claim 1, further comprising a relief valve for adjusting the internal pressure of the dry ice container to a predetermined pressure or less.

7. The freshness preservation device according to claim 6, wherein the carbon dioxide supply unit introduces carbon dioxide discharged by the relief valve and supplies the introduced carbon dioxide into the container.

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