JPH04110581A - Cryogenic refrigerator of double chamber structure capable of controlling concentration of ethylene in it and holding specified humidity and cryogenic storing method - Google Patents

Abstract

PURPOSE:To provide a refrigerator for storing agricultural products, flowers, plant seedlings and bulbs by a method wherein walls of a storing chamber are made such that a film of low density polyethylene is closely adhered to one surface of a plate member having flat rock plates abutted and coupled to each other which are cut out of green tuff and activated in ethylene adhering characteristic by a burning process. CONSTITUTION:Each of two side vertical walls facing to each other in an inner refrigerator I for storing products to be stored is constructed by a panel-like assembly 2 in which rock plates 2' cut out of green tuffs activated in their ethylene adsorption characteristic under a burning process are connected to each there by adhesive agent. Air between the refrigeration chamber 1 and an enclosing member T is cooled by a cold air circulating device 12 to become cooling air, the air is circulated within the spacing 8 so as to cool the entire refrigeration chamber 1 from outside. A cooling coil 9 is connected to a freezer 13 for use in recooling the refrigerant and recirculating it. Ethylene gas discharged out of the stored product passes through a film layer of a polyethylene film 5, is adsorbed into the rock plate 2'. Steam in air in the room can not pass through the film 5, so that a relative humidity of the indoor air can be maintained at a range of 80 to 95%.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention is useful for preserving the freshness of agricultural products, preserving the freshness of flowers, regulating flowering, long-term storage of plant seedlings and bulbs, regulating flowering,
The present invention relates to a low-temperature storage device and a low-temperature storage method for breaking dormancy of bulbs or maintaining the freshness of foods.

The present invention provides an inner refrigerating chamber so as to have a double-chamber structure in the storage, and an outer refrigerating chamber that forms an outer cavity for accommodating the inner refrigerating chamber on the outside of the wall surface of the inner refrigerating chamber. By forcibly circulating cooling air inside the outer cavity or space formed between the inner wall surface of the enclosure and the outer wall surface of the inner refrigerating chamber, and a refrigerator which cools the internal air and maintains the inner refrigerator compartment in a windless state, and which uses green tuff containing zeolite as a construction material for the side walls of the inner refrigerator compartment to adsorb ethylene. The method uses a rock slab with activated properties, and a low-density polyethylene film covering and contacting the surface is attached to a removable support rod and installed in a removable manner on the surface of the rock slab. In a storage warehouse having an inner refrigerating chamber with a gas selectively permeable wall (some of which has a gas-selective permeable wall), an air atmosphere is maintained in the inner refrigerating chamber and whose ethylene concentration and humidity are controlled. By storing fresh agricultural products, flowers, plant seedlings, bulbs, or foodstuffs, it is possible to maintain the freshness of agricultural products and flowers, control flowering, long-term storage of plant seedlings and bulbs, control flowering, and break dormancy of bulbs. The present invention also relates to a low-temperature storage that can maintain the freshness of foods for a long period of time, and transportation using these devices.The present invention also relates to a low-temperature storage method using this storage.

[Conventional technology and issues to be solved]

After harvesting, agricultural products, fruits and vegetables, so-called fruits and vegetables, flowers, plant seedlings, bulbs, etc., generate ethylene gas during storage, and are exposed to an air atmosphere containing ethylene gas higher than the concentration value that occurs during storage. When placed inside, the effects of ethylene, which acts as an aging hormone, affect agricultural products, flowers,
It is known that the freshness of plant seedlings, bulbs, etc. is accelerated, and that foods such as raw meat, ham, cakes, and noodles are also reduced in freshness due to drying due to water evaporation and various other factors.

Various methods have been used to store agricultural products, flowers, plant seedlings, bulbs, or foods after harvest, but none of them are completely satisfactory.

For example, a commonly known method for storing agricultural products and flowers is to pack them in cardboard boxes immediately after harvesting and pre-cool them in a cold air forced circulation low-temperature storage room. The aim is to keep the amount low, suppress water evaporation, and suppress the production of the aging hormone ethylene, which is generated from stress due to increased respiration. However, due to the forced circulation of cold air, it is essential to place them in cardboard boxes or wrap them in film to prevent quality deterioration due to direct blowing of the cold air to the agricultural products and flowers being stored.
Due to the accelerated drying effect caused by wind, a decrease in humidity inside the storage room is unavoidable, and the aging hormone ethylene gas generated from stored agricultural products and flowers saturates the air inside the storage area. There is a risk of accelerating the deterioration or aging of For plant seedlings, such as carnations and chrysanthemums, put them in a plastic bag and store them in the refrigerator with the air removed, or put them in a cardboard box and cover them with newspaper, etc. to prevent them from drying out. In this case, if the carbon dioxide concentration exceeds a certain concentration value, yellowing of the seedlings will occur. It has the following disadvantages.

Furthermore, the storage of bulbs such as lilies, freesia, etc.
A humid storage method is used to preserve the bulbs by placing moist sawdust between them, but the moisture must be added to the sawdust as needed, and care must be taken to keep the temperature at 8 to 12 degrees Celsius.
Due to the relatively high storage temperature required, the consumption of oxygen and the release of carbon dioxide due to the respiration of the bulbs is unavoidable, so storing bulbs in conventional non-ventilated refrigerators requires special ventilation. If care is not taken, the low-temperature storage effect may deteriorate due to interference caused by carbon dioxide gas. In addition, storing bulbs such as collars requires ventilation, appropriate temperature (5 to 80C), and humidity, so in very cold regions, it is necessary to store them at a temperature of 1.5 to 2 cm from the ground.
It is difficult to overwinter by burying bulbs in the ground, or by digging up bulbs in plain areas due to the high ground temperature.

On the other hand, when storing in a low-temperature storage facility that uses forced circulation of cold air inside the warehouse, some attempts have been made to store the product with an ethylene adsorbent such as activated carbon inside the warehouse as an ethylene removal agent. Both methods can satisfactorily store agricultural products, flowers, etc. for only about 3 to 7 days, and are not suitable for long-term storage.

The present invention was made to solve the above-mentioned problems, and includes maintenance of freshness and flowering control of fresh agricultural products and flowers after harvest, long-term storage of plant seedlings and bulbs, flowering control of cut flowers, and dormancy of bulbs. The purpose of the present invention is to develop and provide a highly practical low-temperature storage with a double-chamber structure as a storage that can achieve long-term preservation of food freshness.

[Means to solve the problem]

Previously, one of the inventors of the present invention proposed that ``the whole or part of the wall of a storage container or storage room equipped with a lid or door that can store fresh agricultural products after harvesting and keep the inside airtight.'' The department is
A piece of rock with a thickness of 5 mm to 40 mm, cut from porous green tuff containing zeolite, and whose ethylene adsorption ability has been activated by roasting to remove zeolite crystal water, or this rock. It is composed of a gas-selective permeable composite plate material made by adhering a thin low-density polyethylene film with an average film thickness of 15 to 25 micrometers to the entire surface of one side of a plate-like material made by joining multiple flat plates in the plane direction. In addition, the surface of the low-density polyethylene film closely attached to the rock slab faces the air atmosphere in the interior space of the storage container or storage room, and the other surface of the rock slab faces the open air outside. Fresh agricultural products are stored in the storage container or storage room that is in contact with the storage container, the storage container or storage room is closed, and the ethylene gas generated from the agricultural products is removed from the air atmosphere in the storage container or storage room by the composite plate material. A relative humidity of 80 to 95% in an air atmosphere in which the concentration of ethylene is maintained at a very low level by adsorption and removal, but the escape of water vapor outward from the interior of the storage container or chamber is prevented. He invented and claimed a patent for a method for preserving the freshness of agricultural products, characterized by storing the agricultural products within a temperature range of 1 to 10°C (Patent application No. 1-99
No. 955.

Application filed on April 21, 1999 1 Invention Title: Method for preserving the freshness of agricultural products'').

The technical background behind this invention is as follows. That is, the green tuff containing zeolite is 3~
It is a porous aluminum hydrated silicate mineral with countless extremely small pores of 6 angstroms, and is an inorganic material that can be obtained in large quantities and at a relatively low cost.Since it exhibits various sludge adsorption abilities, it is We conducted research on how to utilize green tuff. As a result, while cooling water is injected onto green tuff containing zeolite, chips are quickly removed, reducing the stickiness of the rock and suppressing temperature rise due to friction. It has been discovered that it is possible to cut a rock block of about 300 mm in width and 500 mm in width into relatively thin plates of about 5 mm in thickness to thick plates of about 40 mm without creating any cracks. This green tuff is cut into a flat plate with a length of 300 mm or less, a width of 500 mm or less, and a thickness of 5 mm to 40 mm, and zeolite-bound water, that is, zeolite crystals, that binds to the zeolite component in the rock of this flat plate. Dehydration treatment by heating or roasting treatment to remove water (also referred to as zeolite water) preferably results in, for example,
When roasted at a temperature in the range of 550° to 600°C for 60 minutes, the zeolite water is removed and the plate material is activated to adsorb and absorb various gases, especially ethylene. It was discovered.

Therefore, one of the inventors of the present invention developed a 5-40 mm thick rock slab (300 mm long x 50 mm wide) of zeolite-containing green tuff activated by the above roasting process and having gas adsorption and absorption ability.
A hexahedral box-shaped container was assembled by using six sheets of 0 mm) as walls and bonding the end surfaces of the plates with an epoxy resin adhesive. Ethylene gas is injected into the air inside this box-shaped container at a predetermined concentration L, and as the ethylene gas inside the container is adsorbed and absorbed by the zeolite-containing green tuff plate material of the wall, the ethylene 1 decreases over time. Observing the temperature change, it was observed that the ethylene gas concentration in the air in the container was rapidly decreasing. However, if the thickness of the Iwate board exceeds 40 mm, the rate of reduction in ethylene concentration becomes worse. However,
It was also observed that the relative humidity of the air inside this container decreased rapidly at the same time, and it was discovered that this was due to the fact that the green tuff rock slabs that made up the walls had a high ability to adsorb and absorb water vapor. The ceiling wall plate of the box-shaped container prepared as above was replaced with a glass plate and glued to create a sealed container.After injecting ethylene gas concentration into this container, the ethylene concentration of the air inside the container changed over time. We also observed a decrease in the relative humidity of the air inside the container over time, but the trend of this decrease was different from that in the case of the aforementioned container whose hexahedral walls were entirely composed of zeolite-containing green tuff plates. It was recognized that it is similar to When fresh leafy vegetables (e.g. spinach) were placed in each of the two types of containers mentioned above, which were kept at a low temperature by being stored in a commercially available refrigerator that blows and circulates cold air inside the refrigerator, it was found that the leafy vegetables were Although the vegetables did not turn yellow, they were observed to wilt rapidly, indicating that the leafy vegetables were far from being able to maintain their freshness. As a result of investigating the cause of this, it was found that the wilting phenomenon of leafy vegetables is caused by a rapid decrease in the relative humidity of the air inside the container.

Therefore, one of the inventors of the present invention found out as a result of the previous experiment that a rock slab of zeolite gold-phase green tuff whose gas adsorption and absorption ability was activated by roasting treatment was simply used as a wall. When agricultural products such as leafy vegetables are stored in a box-shaped container, the ethylene gas generated by the agricultural products can be removed by adsorption and absorption from the air atmosphere inside the container, even when kept at low temperatures. However, since water vapor is also removed, the relative humidity of the air atmosphere inside the container rapidly decreases, making it less effective as a storage container for long-term freshness preservation of agricultural products even at low temperatures. They found that the method did not work, and found that there remains a technical problem in which means must be devised to prevent a rapid decrease in the relative humidity of the air within such a container.

Moreover, in order to maintain the freshness of agricultural products for a long time, it is necessary to
It has been found necessary to store the product in an air atmosphere exhibiting a relative humidity in the range of 80-95% at low temperatures in the range of ~10°C. Furthermore, it is desirable that the plants of agricultural products continue to respire oxygen at all times after harvesting, or that oxygen respiration be suppressed in order to maintain freshness. Although it is desirable to have a high carbon dioxide concentration and a low oxygen concentration, it was also recognized that the oxygen concentration should not be so low as to cause the produce to undergo anaerobic respiration and lead to spoilage. In order to create a storage container that can easily provide an air atmosphere that satisfies these requirements for preserving the freshness of agricultural products, it is necessary to use zeolite as a structural wall for constructing the storage container. A thin low-density polyethylene film with an average thickness of 15 to 25 micrometers is coated on one side of a 5 to 40 mm thick rock slab cut from porous green tuff and activated to have ethylene adsorption ability by roasting. It has been found that a composite board made of 1F of Iso film is suitable and exhibits selective permeability for various gases. The above-mentioned composite board having such an intimate low-density polyethylene film absorbs ethylene from the ethylene-containing air present in contact with the low-density polyethylene film layer on one side of the board.
It is recognized that ethylene has the ability to remove ethylene from the air by adsorbing into the tuff plate layer while permeating the film layer, and has moderately low moisture permeability, in other words, high moisture retention. It has been observed that the ethylene content, once adsorbed, can eventually be released by diffusion into the open air directly adjacent to the tuff slab layer on the opposite side of the polyethylene film layer.

After all, in the above-mentioned previous invention, one of the present inventors found that the surface of a green tuff plate material containing zeolite with a thickness of 5 to 40 mm whose ethylene adsorption ability was activated by roasting treatment. By constructing a storage container or a storage room from a composite plate material with a thin low-density polyethylene film of 15 to 25 micrometers adhered to the surface, the air inside the storage room is eliminated by the generation of agricultural products stored in the storage container or storage room. The desired ethylene gas is introduced into the polyethylene film layer, and the ethylene gas that permeates through the polyethylene film is quickly absorbed by the gas adsorption ability of the signboard layer and then passes through the signboard layer, while the ethylene gas that passes through the polyethylene film , the indoor humidity is maintained without rapid decline, and the selective permeation of oxygen, carbon dioxide and nitrogen gases is promoted; It was discovered that this material is significantly superior to storage containers made only from film.

Furthermore, we continued research on using storage rooms made of the above composite board materials to keep agricultural products fresh, and as a result of investigating the temperature and humidity conditions that are good for keeping agricultural products fresh, we found that a temperature of 1 to 10 degrees Celsius in the above storage room When stored in an air atmosphere maintained at a temperature within a range of 80 to 95% relative humidity, spinach, a soft vegetable, can be stored for more than 20 days, and Sudachi can be stored for more than 60 days.
It has been found that flowers, such as cut flowers such as carnations, can maintain substantially the same appearance and freshness as they did immediately after being harvested for a long period of 50 days or more. Besides, cucumber,
Eggplant, tomato, broccoli, kabosu, peach, green plum,
I experimented with strawberries, melons, fresh shiitake mushrooms, lettuce, cabbage, carrots, etc., and all had great results.

Based on these findings, the present invention was completed.

Furthermore, in order to improve the practicality of the storage container or storage chamber used in the storage method according to the previous invention related to the above-mentioned Japanese Patent Application No. 1-99955, and to expand the scope of use, the present inventors further This time, we conducted research to make improvements. the result,
Depending on the type of goods to be stored and the different storage purposes, the rate of removal of ethylene from the air atmosphere within the storage room may be increased and/or the humidity level that can be maintained in the air atmosphere within the storage room may be controlled to be high or low. It was recognized that what could be done was of practical importance. And in order to do these things,
The film thickness of the polyethylene film in the composite board consisting of a green tuff rock slab and a low-density polyethylene film closely adhered to it, which constructs the wall of the storage room, is 15.
It has been found that it is best to be able to adjust the amount within the range of ~25 micrometers depending on the type of article to be stored and/or the difference in the purpose of storage. .

However, the close contact between the Iwate board layer and the polyethylene film layer in the composite board material used as a construction material for the wall of the storage room in the above-mentioned previous invention is due to the double-sided adhesive between the two layers. The polyethylene film layer is integral with the rock slab because the adhesive tape is arranged in a checkered or spotted pattern or by adhesive bonding with a liquid adhesive. Therefore, in order to suitably adjust the thickness of the polyethylene film layer depending on the case, the entire structure must be replaced together with the rock slab, which is inconvenient. As a result of research, the present inventors have found that it is possible to attach a low-density polyethylene film to a green tuff rock slab using double-sided adhesive tape or adhesive to separate the low-density polyethylene film into a separate rectangular shape without having to adhere the low-density polyethylene film tightly to the rock slab. The film, which is stretched and supported by a support frame such as When removably attached to the wall of the storage room, it is substantially the same as the above-mentioned composite plate material used in the previous invention in terms of selective adsorption of ethylene gas, permeability, and moisture permeation prevention properties. It was discovered that certain performance could be obtained. Moreover, when it is desired to change the thickness of the polyethylene film, the polyethylene film used can be removed together with the support frame and replaced with another support frame supported by stretching a polyethylene film with a different thickness.・It becomes possible to adjust the thickness of the film depending on the purpose of storage.

Furthermore, in order to quickly and efficiently cool the air atmosphere inside the storage chamber containing the stored articles to a desired low temperature and to efficiently maintain the desired low temperature for a long period of time, it is necessary to cool down a portion of the wall of the storage chamber or Multiple parts are made from materials with good heat conductivity,
Then, the entire storage chamber is surrounded by an outer enclosure that encloses and accommodates the storage chamber, and a closed space surrounding the storage chamber is left between the storage chamber and the enclosure that surrounds it. It is better to adopt a method in which cold cooling air is forcibly circulated in the space and the entire wall of the inner storage chamber, and thus the entire storage chamber, is cooled with the cooling air from outside the storage chamber. I found out. If this cooling method is adopted, the storage room in which the stored articles are stored is maintained in a windless state, so that it is possible to eliminate the possibility that the articles being stored may be exposed to air currents and the articles may be dried more quickly.

The present invention has been completed based on the above findings of the present inventors.

Therefore, according to the first aspect of the present invention, a wall portion made of a material with good heat conductivity is provided with an opening/closing door capable of storing articles to be stored at a low temperature and keeping the interior of the chamber in a sealed state and a windless state. An inner refrigerating compartment with a space between the inner refrigerating compartment and the refrigerating compartment sharing the above-mentioned opening/closing door of the inner refrigerating compartment or with a separate opening/closing door, but leaving a space between the inner refrigerating compartment and the inner refrigerating compartment. An outer enclosure made of a cold and heat insulating material that surrounds and accommodates the entire chamber, and an inner refrigerating chamber attached to the inside of this outer enclosure and between the outer enclosure. and a cold air circulation device disposed in the space of the refrigerator and circulating cooling air within the space to cool the entire inner refrigerator compartment from the outside of the refrigerator compartment. In a refrigerator, the side wall surface and/or constituting the inner refrigerating compartment for storing items to be stored at low temperatures.
At least a portion of the ceiling surface and/or floor surface is made of a material with good heat conductivity, and at least one wall of the four lateral walls constituting the internal refrigerating room is The body, preferably two or more walls, is cut in whole or at least in part from a porous green tuff containing zeolite and is roasted to remove the zeolite water of crystallization. From a flat panel-like assembly made of a single rock slab with a thickness of 10 mm to 20 mm whose ethylene adsorption ability has been activated through treatment, or a plate-like material made by joining multiple rock slabs in the plane direction. of the surface of said flat panel assembly of rock slabs which are constructed and which form the walls of said inner cold storage chamber or portions thereof; On the rock slab surface of the panel-like assembly facing the air atmosphere is a thin low-density polyethylene film with an average thickness of 15 to 25 micrometers, stretched and supported on a self-supporting support frame. The panel assembly is installed in contact with the surface of the rock slab and covers the entire surface of the rock slab, and the support frame that supports the polyethylene film is attached to the inner cold room by a removable fixture. A double-chamber cold storage for storing agricultural products, flowers, plant seedlings, bulbs or food products is provided, characterized in that the storage is removably attached.

The distribution area of green tuff that can be used in the present invention is almost all over the country from Hokkaido to Honshu, Shikoku, and Kyushu, or it is mainly found in eastern Japan, and the main production areas are as follows. (1) Hokkaido, Nagatobe district, (2) Akita prefecture, Futatsui district, Hesawaki district, Yokote district, Itado district, (3)
) Iwate prefecture, Shizukuishi district, (4) Miyagi prefecture, Shiroishi district, (5)
Yamagata prefecture, Itaya district, (6) Fukushima prefecture, Higashino district near Iizaka,
Tenei district, Nishiaizu district, (7) Tochigi prefecture / Okama district, (8
) Gunma prefecture, Tsukiyono district, Niiharu district, (9) Aichi prefecture, southwestern Shiretoko Peninsula district, (1o) Shimane prefecture, Iwamita EEI district,
Umaji district, 11) Kagoshimagu/Koriyama district. This type of green tuff has natural zeolite as its basic component.

In the storage of the present invention, the upper limit of the thickness of the green tuff Iwate plate used is limited to 20 millimeters (mm), compared to the upper limit set at 40 nm in the previous invention. This is mainly to reduce the weight of the storage and to hasten the process by which ethylene, once adsorbed on the rock slab, passes through the rock slab and is released into the circulating cooling air outside. Even if the thickness of the Iwate board used is increased to 30 mm instead of the Iwate board having a maximum thickness of 20 mm, the storage effect etc. exhibited by the storage of the present invention will not substantially change.

To further explain the double-chamber structure low-temperature storage of the present invention, it is made by cutting out porous green tuff containing zeolite and having its ethylene adsorption ability activated by roasting treatment.
An average installed by being supported by a support frame in contact with the surface of a panel-like assembly consisting of a sheet of Iwate board of 0 mm to 20 mm or multiple sheets of Iwate board joined in the plane direction. A thin low density polyethylene film with a film thickness of 15 to 25 micrometers faces the air atmosphere in the interior space of the refrigerator compartment with its inward facing surface. The outward facing surface of the Iwate board is in contact with the cooling air circulating in the space between the inner cold room and the outer enclosure, so that the agricultural products, flowers and plant seedlings stored in the inner cold room can be protected. , the aging hormone ethylene gas generated from the bulbs or food flows from the air atmosphere inside the refrigerator room through the space outside the refrigerator room through adsorption, absorption, and permeation of ethylene through the cooperative action of the polyethylene film and Iwate board. The ethylene gas removed into the cooling air is discharged from the exhaust pipe to the outside of the enclosure in a timely manner together with a portion of the cooling air, thereby reducing the air atmosphere in the inner refrigerator compartment. can be maintained at extremely low ethylene concentrations. On the other hand, the humidity of the air inside the inner refrigerator compartment is
The installed low-density polyethylene film has high gas permeability but relatively low moisture permeability, which prevents water vapor from escaping from the inside of the internal refrigerator compartment to the outside. Therefore, the relative humidity in the air atmosphere in the refrigerator room can be maintained within the range of 80 to 95%.

In the storage of the present invention, the inner refrigerating chamber surrounded by the outer enclosure has only one of the walls (bottom wall, four side vertical walls, and ceiling wall) constituting it. or parts of it are wholly or partially made of a material with good heat conductivity, such as aluminum, aluminum alloys (e.g. duralumin alloys), copper or iron, or stainless steel sheets.One wall. It is also possible to make a large part of it from a material with good heat conductivity, and the rest of it from a material with low heat conductivity but good mechanical strength.One or two of the ceiling wall and side wall of the inner refrigerator compartment The surface is preferably made of a material with good heat conductivity, such as a thin aluminum plate, and one of the side walls and the bottom wall of the inner refrigerator compartment is preferably made of a stainless steel plate, which may be combined with suitable reinforcements or supports. Heat conduction from the air inside the refrigerator compartment to the cooling air flowing outside through the walls made of materials with good heat conductivity that make up the interior refrigerator compartment occurs efficiently. can maintain low temperature.

In the storage of the present invention, among the walls constituting the inner cold room, the side walls other than those made of a material with good heat conductivity are cut out of porous green tuff containing zeolite. It is made from a flat panel-like assembly made of plate-like materials made by piecing one or more Iwate boards together in the plane direction. In order to join multiple Iwate boards together in a planar direction to make a plate-like material, the end sides of each of the Iwate boards that will be the joints are directly bonded with an adhesive, such as a silicone adhesive. However, it is also possible to interpose a thin piece of synthetic resin or a thin piece of metal such as iron between them as an intervening material and then bond them together with an adhesive. For example, multiple pieces of Iwate board cut into rectangles, e.g. 5 to 6 pieces.
A plate-like material can be formed by aligning the sheets flat with their longitudinal side end surfaces butted against each other and joining the adjoining longitudinal side end surfaces with an adhesive. In the plate material formed in this way, the vertical side edges of the plate material are formed by a matrix of the shorter end sides (the end sides that are not bonded with adhesive) of each Iwate plate element making up the plate material. It is possible to vertically fit and fix a gutter-shaped reinforcing frame with a U-shaped cross section to both of the frames, and to fix the vertical gutter-shaped reinforcing frame that is fitted and attached in this way. At the top, there is a rectangular metal plate installed horizontally along the top end of the Iwate board joint plate material.
For example, stainless steel plates or strong synthetic resin plates can be joined, and this horizontal plate can be used to fix the spliced Iwate plate to the wall that forms the ceiling of the internal cold storage room or to other locations. Provides a holding section for holding the device.

The spliced Iwate board material manufactured as described above with or without gutter-like reinforcing frames on the side edges is made by holding two or more of these sheets in an upright position and processing the end surfaces. It is assembled from a plurality of plate-like materials by butting them together and arranging them flat, and filling the gap between the butted end faces of each of the plate-like materials with a sealing agent or double-sided adhesive tape to make them stick together. Panel-like assemblies can be produced. This panel-like assembly can constitute the side wall of the inner refrigerating compartment. It is also possible to insert struts between each of the spliced Iwate plate members forming this panel-like assembly, and to join the longitudinal end faces of the plate members to the struts.

The inner refrigerating chamber in the storage of the present invention uses a panel assembly including the spliced Iwate board produced as described above as a constituent material for all or part of the side wall thereof, and the other side wall Using materials with good heat conductivity for the remaining parts, ceiling walls, and bottom walls, it is constructed as one room with no gaps using conventional construction methods.

Naturally, this inner refrigerating chamber is provided with an opening/closing door that can be opened and closed for loading and unloading articles to be stored, but this inner opening is of a structure that allows the interior of the inner refrigerating chamber to be sealed when closed. It may be convenient if the opening/closing door of the inner refrigeration compartment is the same as the opening/closing door of the outer enclosure surrounding and accommodating this inner refrigeration compartment; The communication passage between the opening/closing door of the chamber and the opening/closing door of the outer enclosure is preferably constructed so as to be surrounded by an extension portion projecting like a flange from one side wall of the inner refrigerating chamber. Thereby, the communication passage section is cut off from the space left between the inner refrigerating chamber and the outer enclosure surrounding it, that is, from the outer cavity, by the flange-like projecting extension. 1. This prevents the flow of cooling air circulating within the space from entering the interior of the refrigerator compartment through the doorway of the refrigerator compartment.

However, it is also possible to provide several inner refrigerating compartments within the outer enclosure, to the extent that it allows the free circulation of the cooling air flow, in which case the opening and closing door of the inner refrigerating compartment may be constructed separately and independently from the opening/closing doorway of the outer enclosure.

In the storage of the present invention, a membrane is installed inside the refrigerator compartment in contact with a panel assembly made of spliced Iwate boards constituting the vertical wall of the inner refrigerator compartment provided as described above. A rectangular support frame stretched with a low-density polyethylene film with a thickness of 10 to 20 mm is installed upright and removable using a removable fixture, and the polyethylene film stretched and supported by the support frame is shaped like a panel. It is arranged so as to come into contact with and cover the entire surface of each Iwate board making up the assembly. Depending on the size of the total surface area of the Iwate board, a plurality of support frames may be installed to cover the entire surface of the Iwate board, each supported by a polyethylene film stretched thereon. Further, the support frame for supporting the polyethylene film may be of a lattice type having vertical bars, horizontal bars, or vertical and horizontal bars.

It is preferable that at least two of the four side walls of the inner refrigerating chamber are each entirely constructed from a panel-like assembly made of the above-mentioned Iwate board.

Further, the thickness of the green tuff rock plate used is in the range of 10 mm to 20 mm, and the average thickness of the low density polyethylene film is preferably in the range of 15 to 25 micrometers.

Furthermore, out of the total area of the inward facing surfaces of the walls of the inner refrigerating chamber, the surfaces of the rock slabs of the panel-like assembly made of cut rock slabs of green tuff that are in contact with the low density polyethylene film are The total area occupied by the inward facing surfaces of the rock slabs that are in contact with the inner cold storage room is determined by the total area occupied by the inward facing surfaces of the rock slabs. The area is sufficient to adsorb and remove ethylene to maintain O, 1 ppm or less, and the other wall portions of the inner refrigerating compartment may be constructed of gas-impermeable or poorly permeable materials. .

Furthermore, each of at least three of the walls on the west side of the inner cold room, and also the ceiling wall if desired, are made of panel-like assemblies made of the above-mentioned spliced rock slabs. It is also possible to consist of

In the low-temperature storage according to the present invention, the entire inner refrigerating chamber is made of a cold-insulating material that surrounds and accommodates the refrigerating chamber, leaving a space outside the inner refrigerating chamber, that is, an outer space. surrounded by an outer envelope consisting of The walls constituting this enclosure are made of a material that is cold-insulating and impermeable to debris, and is laminated with layers of heat-insulating material such as polystine foam or urethane foam, as desired. Synthetic resin plates, concrete plates, iron plates, iron alloy plates, steel plates, aluminum plates,
It can be a wooden plate or a resin-coated steel plate or a resin-impregnated woven fabric. This outer enclosure may be provided with suitable reinforcements and constructed using conventional construction techniques. This outer enclosure acts as an outer container for the inner refrigerating chamber, and the space left between the outer enclosure and the inner refrigerating chamber, that is, the outer cavity, contains , has a structure with an opening/closing door through which cooling air can be circulated or with which stored articles can be carried in and out of the inner refrigerating chamber while allowing the circulation of this cooling air. This outer enclosure includes an exhaust pipe with an on-off valve for discharging air from the space between the inner refrigerator compartment and the outer enclosure surrounding it to the outside of the refrigerator, and An air intake pipe with an on-off valve can be installed to take in air from the surrounding atmosphere.

In order to cool and circulate the cooling air flowing through the space between the inner refrigerating room and the outer enclosure surrounding the inner refrigerating room, it includes a cooling coil pipe through which a low-temperature refrigerant flows and a cold air circulation fan. A cold air circulation device is located at a suitable location in the outer cavity between the inner refrigerating compartment and the surrounding outer enclosure. Preferably, said cooling coil tube is connected to a refrigerator located outside said outer enclosure for recooling and recirculating the refrigerant therein. Furthermore, both the inner refrigerating chamber and the above-mentioned outer cavity outside thereof can be provided with drain pipes at their bottoms for draining accumulated condensate water in a timely manner.

In the present invention, it is necessary that the low-density polyethylene film layer in contact with the seamed plate-like material of the rock flat plates forming the inner refrigerating compartment be placed in such a direction as to be in direct contact with the air inside the refrigerating compartment. If the tuff layer is placed in the opposite direction, the moisture will be rapidly removed from the air inside the refrigerator room that it is in direct contact with, making it impossible to maintain the humidity of the inside air within a suitable range. Since it is suppressed by the layer, it is prevented from diffusing into the cooling air in the outer space.

In the present invention, a low-density polyethylene film is stretched and supported by a supporting frame in contact with the surface of the rock flat plate that forms the wall of the inner refrigerating chamber, so the film can be attached or detached depending on the purpose of use. This is convenient because the film can be replaced using a so-called cassette system. Furthermore, when joining multiple rock plates together in a planar direction, it is best to use silicone adhesive to adhere the end sides of the multiple plates that will be the joint, in terms of airtightness.

Hereinafter, embodiments of the low temperature storage of the present invention will be described with reference to the accompanying drawings.

FIG. 1 schematically and diagrammatically shows an embodiment of a double-chamber cold storage according to the invention in vertical section.

In Figure 1, numeral 1 is an inner refrigerating room for storing goods to be stored, and each of the two vertical walls on the opposite sides of this refrigerating room has an ethylene adsorption capacity activated by roasting treatment. It is composed of a panel-like assembly 2 formed by flatly assembling plate-like bodies made of cut Iwate boards 2' of green tuff joined together with adhesive.

The bottom wall 4 of the refrigerator compartment (2) is made of a stainless steel plate, and the ceiling wall 3 is made of an aluminum plate. The bottom wall 4 is suitably supported by a support beam (not shown) and is mounted on a pedestal 6.
It is placed on top of. Two vertical walls (not shown) on opposite sides of the refrigerator compartment 1, other than the wall body 2 which is a panel-like assembly including the Iwate board 2', are the side walls of the refrigerator compartment 1. , made of stainless steel plates, one of which is naturally provided with a doorway (not shown) for loading and unloading stored items, and this doorway is formed by a flange-shaped doorway surrounding the doorway and protruding from the refrigerator compartment 1. Via the extension,
It is connected to an opening/closing door (not shown) provided in an outer enclosure 7 disposed outside the refrigerator compartment 1 . The outer enclosure 7 is a box made of a stainless steel plate, an aluminum plate, a steel plate, or a vinyl chloride resin-coated steel plate laminated with a foamed polyurethane insulation layer.

A space or empty chamber 8 is left between the refrigerating chamber 1 and the enclosure 7, in which air is present. This air is cooled by a temperature-controllable cold air circulation device 12 that includes a cooling coil tube 9 through which a low-temperature refrigerant flows and an air circulation fan IO driven by a motor 11, and becomes cooling air. It flows and circulates in the direction of , cooling the entire refrigerator compartment 1 from the outside. The cooling coil 9 is connected to an outer refrigerator 13 which recools and recirculates the refrigerant.

An air suction pipe 1 with an on-off valve is installed at a suitable location in the enclosure 7.
4 is inserted, and air is introduced into the space 8 from outside the enclosure 7 in a timely manner by opening and closing the valve as desired. Further, an exhaust pipe 15 with an on-off valve is inserted into the enclosure 7, and the ethylene-containing air is exhausted from the space 8 to the atmosphere outside the enclosure 7 in a timely manner by opening and closing the valve as desired.

Inside the inner cold room 1, there is a low-density material facing the panel assembly 2 made of plate-like materials joined with Iwate boards 2' and in contact with the inward surface of the Iwate boards 2'. polyethylene·
The film 5 is stretched and supported by a rectangular lattice-shaped support frame 5A. However, in FIG. 1, the film 5 supported by the support frame 5A is illustrated at a position apart from the panel-like assembly 2, but in reality they are in contact with each other. This film 5 is in contact with the air atmosphere inside the refrigerator compartment 1 on the film surface opposite to the surface that contacts the Iwate board, and the ethylene gas etc. released from the stored items are released into this air atmosphere. , passes through the membrane layer of the polyethylene film 5 and is adsorbed into the Iwate board 2'. On the other hand,
Since almost no water vapor in the indoor air atmosphere can pass through the film 5 due to the moisture retention properties of the film 5, the relative humidity of the indoor air atmosphere can be maintained at a value in the range of 80 to 95%.

FIG. 2 schematically shows a horizontal section through the embodiment of the storage according to the invention shown in FIG. 1, taken vertically along the dashed line A-A' shown in FIG. The cross section corresponds to the cross section shown in FIG.

As shown in FIG. 2, a polyethylene film 5 stretched and supported by a lattice-shaped support frame 5A is in contact with a panel-like assembly 2 formed by assembling plate-like materials made of Iwate boards 2'. It is placed to cover the entire surface of the rock slab. Also,
In FIG. 2, reference numeral 16 indicates a side wall of the refrigerator compartment made of a stainless steel plate, and 17 is another side wall of the refrigerator compartment made of a stainless steel plate. This side wall 17 is provided with a doorway, from which a communication passage 18 extends. The refrigerator compartment 1 is connected to the outer enclosure 7 by a communication passage 18.
The passage 18 is connected at a doorway provided in the enclosure 7, and the passage 18 is connected to an extension 19 projecting in the form of a flange from the side wall 17.
It is surrounded by and cut off from the space 8.

The doorway of the enclosure 7 includes a door 20 that can be opened and closed.

FIG. 3 is an enlarged side view of the panel-like assembly 2 made of the plate material of the Iwate board 2', which constitutes one side wall of the inner refrigerating chamber 1 shown in FIGS. 1 and 2. FIG. 2 is a diagram when viewed from the space 8 side.

Therefore, film 5 does not appear. In Fig. 3, the plate material, which is made up of six Iwate boards 2' arranged flat and joined together with adhesive, has a gutter-shaped reinforcing frame with a U-shaped cross section at each vertical side edge. 21 is fitted and reinforced. Three sets of such plate-shaped materials are assembled flat with each other in contact with each other at the end surface 22 of the reinforcing frame 21, and constitute the panel-shaped assembly 2 as a whole. A double-sided adhesive tape is inserted into the end face 22 to close the gap.

FIG. 4 shows the inward facing signboard surface (
A rectangular support in the form of a lattice with vertical and horizontal bars for supporting the polyethylene film 5 installed in contact with the air-facing side of the internal space of the inner cold room 1 and covering the surface of the rock slab. It is a perspective view showing the state where two sets of frames 5A are arranged in parallel.

This support frame 5A is a panel-like assembly 2 including the Iwate board 2'.
The surface of the support frame facing the is made of low-density polyethylene.
A film (indicated by 5 in FIGS. 1 and 2, but not shown in FIG. 4) is stretched and supported by a support frame 5A. Although the two sets of support frames 5A are shown separated from each other in FIG. 4, they are actually installed adjacent to each other. Additionally, the number of support frames installed is increased so that the polyethylene film supported by the frames covers the entire surface of the Iwate board that forms the side wall of the refrigerator compartment.

Furthermore, the present inventors have used the double-chamber structure low-temperature storage according to the first invention described above, and have used it for maintaining the freshness of fresh agricultural products and flowers, and for long-term storage of plant seedlings and bulbs. He continued research on its use in regulating flowering, breaking dormancy in bulbs, and preserving the freshness of food.

Then, we investigated the temperature and humidity conditions that are good for preserving agricultural products, flowers, plant seedlings, bulbs, and foods, as well as the flow rate of cooling air. As a result, temperatures in the inner cold room of said storage range from -3°C to +12°C, and from 80 to 95°C.
When stored products are stored in an air atmosphere maintained in a windless state with a relative humidity of 50%, agricultural products such as sudachi and kabosu will last for more than 80 days, and soft vegetables such as shungiku, spinach, and mitsuba will last for more than 20 days.
Flowers, such as irises, which are the most difficult to store among cut flowers, can be stored fresh for more than 20 days when stored in a bud state just before blooming. It was found that this is possible, and that there is no problem with the flowering state after being taken out of storage.

In addition, carnations in bud state can be stored for a long period of 60 days or more to maintain the same freshness as immediately after harvesting, and plant seedlings for cuttings of chrysanthemums can be stored for 60 days or more, and lily bulbs can be stored for a long period of time. It was also found that it can be used to control flowering and break dormancy. They also discovered that raw meat and noodles can be kept intact for about a week.

In addition, agricultural products such as tomatoes, broccoli, strawberries, peaches, melons, persimmons, pears, fresh shiitake mushrooms, flowers such as roses, lilies, gentians, irises, and gladioli, plant seedlings carnations, freesia bulbs, collars, and food products include He experimented with preserving ham, cake, wine, etc., and found excellent results in all of them. The second invention was completed based on these findings.

Therefore, according to the second aspect of the present invention, a wall portion made of a material with good heat conductivity is provided with an opening/closing door capable of storing articles to be stored at a low temperature and keeping the interior of the chamber in a sealed state and a windless state. The inner refrigerated room where the night is stored may share the above-mentioned opening/closing door of the inner refrigerating room, or be provided with a separate opening/closing door, but leave a space between the inner refrigerating room and the inner refrigerating room. An outer enclosure made of a cold and heat insulating material that surrounds and accommodates the entire refrigerator compartment; A low-temperature refrigerator having a double-chamber structure and having a cold air circulation device disposed in a space between the two and circulating cooling air within the space to cool the entire inner refrigerator compartment from the outside of the refrigerator compartment. At least a portion of the side wall surfaces and/or ceiling surface and/or floor surface constituting the inner refrigerating room for storing items to be stored at low temperatures are made of a material with good heat conductivity. In addition, at least one wall of the four walls on the four sides constituting the inner refrigerating compartment, preferably two or more walls, is A piece of Iwate slab with a thickness of IO mm to 20 mm, which is cut entirely or at least in part from porous green tuff containing zeolite, and whose ethylene adsorption capacity has been activated by a roasting treatment to remove zeolite crystal water. It is made from a flat panel-like assembly consisting of a sheet or a plurality of Iwate boards joined in the plane direction, and the wall of the inner refrigerator room or a part thereof is Of the surfaces of the flat panel-like assembly made of the above-mentioned Iwate boards, on the surface of the rock-flat plate of the panel-like assembly facing the windless air atmosphere inside the inner refrigerating room,
Average film thickness 15 when stretched and supported on a self-supporting support frame
A thin low-density polyethylene film of ~25 micrometers is installed in contact with the rock slab surface of the panel-like assembly to cover the entire rock slab surface, and the above-mentioned support frame supporting the polyethylene film is included inside. A double-chamber low-temperature storage facility is used, which is removably attached to the cold storage room using removable fixtures. Seedlings,
Store bulbs or fresh food, close the inner refrigerator compartment,
By adsorbing ethylene gas and carbon dioxide generated from stored agricultural products, flowers, plant seedlings, bulbs, or foods from the windless air atmosphere in the inner refrigerator compartment by the Iwate board through the Botethylene film. The scum adsorbed on the Iwate board is released into the cooling air circulating in the space between the inner refrigerating chamber and the outer enclosure, and the scum is released into the circulating cooling air. The air containing ethylene gas is discharged outside the refrigerator in a timely manner through an exhaust pipe attached to the outer enclosure, thereby maintaining an extremely low ethylene concentration in the inner refrigerating chamber. Yes, but the relative humidity of the air atmosphere is 80~80 in a windless condition in an air atmosphere where the escape of water vapor from the inside of the inner refrigerating room to the outside is almost or completely prevented.
Within the range of 95% and the temperature is -3℃ to +1℃
Provided is a low-temperature storage method characterized by storing the agricultural products, flowers, plant seedlings, bulbs, or foods within a range of 2°C.

In the method of the present invention, agricultural products, flowers, plant seedlings,
If a relative humidity of 80 to 95% is initially provided by evaporation of moisture adhering to the bulbs or food or by spraying water, the inner cold room itself will have a moisturizing effect, so there is no need to take measures to replenish moisture later. 80-95% relative humidity can be maintained. It is usually observed that humidity can quickly rise to 95% or more simply due to water transpiration from agricultural products, flowers, plant seedlings, bulbs or food products.

However, there is no problem in replenishing the storage container or storage room with moisture.

Furthermore, if the humidity of the air atmosphere within the internal refrigerating chamber is excessive for the stored products, suitable dehumidification or moisture absorption means may be provided in the chamber.

Next, in order to compare the double-chamber structure low-temperature storage of the first invention with ordinary commercially available forced-air refrigerators and constant-temperature, high-humidity refrigerators, we will compare the gas permeability measured inside each of them. The humidity values are shown in Table-1.

Table 1 However, the thickness of the Iwate board layer of the element of the panel assembly forming the side wall of the inner cold room of the storage of the present invention tested was 10 mm.
The thickness of the low density polyethylene film layer used was 15 micrometers.

According to the values in Table 1 above, the double-chamber structure low-temperature storage of the present invention has significantly superior scum permeation performance and moisture retention compared to ordinary forced-air refrigerators, and is also superior to constant-temperature, high-humidity refrigerators. Even in comparison, it is recognized that the gas permeation performance is significantly superior. This means that the Iwate board material used in the present invention selectively permeates the oxygen, carbon dioxide, and nitrogen gases in the air inside the inner refrigerating compartment to the outside of the inner refrigerating compartment, and also allows the water vapor that slightly passes through the polyethylene film layer to pass through the Iwate board. This is presumed to be due to the fact that the layer adsorbs and absorbs water vapor, thereby suppressing the diffusion and permeation of water vapor. The reason for this is clear from the fact that the effective moisture content in the signboard layer increased slightly between before and after the experiment.

Furthermore, a comparison of the ethylene gas removal performance in the three types of storage used in the above test was conducted at an initial ethylene concentration of 5 ppm, and changes in the ethylene concentration decreasing over time were measured using an ethylene monitoring device.

The measurement results are shown as a curve diagram in FIG. 5 of the attached drawings.

From the curve in Fig. 5, it is recognized that in the double-chamber structure low temperature storage of the present invention, the ethylene concentration of the air in the inner cold room has decreased to 0.1 ppm or less after 36 hours, which is normal. It is also recognized that the ethylene removal performance is significantly superior to forced ventilation type refrigerators and constant temperature and high humidity refrigerators.

Next, the present invention will be explained with reference to examples.

Example 1 A double-chamber structure schematically shown in FIGS. 1 to 4 of the accompanying drawings was constructed, and two side walls of the inner refrigerating compartment were fabricated as follows. Specifically, green tuff containing zeolite (from Tsukiyono, Numata City, Gunma Prefecture) was cut into a flat plate with a thickness of 15 mm, a length of 280 mm IJ, and a width of 450 mm. After air drying, this rock flat plate was roasted at 550 to 6008 C for 60 minutes. The ethylene adsorption ability was activated by calcination treatment. The roasted rock plates were pieced together into a set of 6 to form a plate-like material. A stainless steel reinforcing frame measuring 1,800 mm in length and 450 mm in width was fitted to the side edges of the plate-shaped body. In this way, three sets of plate-like materials with reinforcing frames were arranged flat and assembled into a panel-like assembly. The panel-like assemblies made of rock slabs constituted each of two mutually facing side walls of the inner refrigerating chamber. A supporting frame (supporting frame) facing the rock flat plate surface of each panel-like assembly forming these two side walls and supporting it by stretching a low-density polyethylene film with an average film thickness of 15 μm in contact with the surface.
Two sets of lattice-shaped support frames with vertical and horizontal bars were removably installed.

At this time, the entire inward facing surface of the panel-like assembly made of rock flat plates forming the two side walls of the four sides of the inner refrigerating room is entirely covered with polyethylene film supported by the support frame. A plurality of support frames were placed with polyethylene film stretched over them so that they could be completely covered. The support frame was fixed using removable screw fittings. The two side walls of the inner refrigerating chamber other than those consisting of panel-like assemblies made of rock slabs are made of thin stainless steel plates, and the ceiling surface of the inner refrigerating chamber is made of aluminum plates;
The bottom was made from stainless steel plate. This inner cold room was surrounded, leaving a space, by an outer enclosure made of sheet steel with a foamed polyurethane insulation layer. In the space left between the inner refrigerator compartment and the outer enclosure, low-temperature cooling air cooled by a temperature-controlled cold air circulation device was circulated. This cooling air flowed along the outer periphery of the inner refrigerating chamber to perform cooling. The door for carrying in and out articles to be stored was made of a glass plate in order to observe the state of storage of stored articles in the refrigerated room. In the inner refrigerating room of the double-chamber structure low-temperature storage according to the present invention, 50 boxes containing 1 box of 2 kg of sudachi (a total of 100 kg of sudachi) were stored, and the door was closed and the inside was opened. Keep the refrigerator compartment closed
An automatic thermometer and hygrometer as well as the sensors of an ethylene monitor were placed inside the inner cold room, and the automatic ethylene concentration recorder was placed outside the storage. Due to water evaporation from the sudachi, the humidity of the air inside the internal refrigerator reached 95% in about 30 minutes. The air atmosphere in this refrigerator room was maintained at a temperature of 2° C. and relative humidity of 95% according to the method of the present invention, and the preservation state of the Sudachi was observed through the glass plate on the door surface. For comparison, a refrigerator of the same type as the above-mentioned refrigerator of the present invention was prepared, except that it used roasted green tuff rock plate material but had an inner refrigerating chamber with a double-chamber structure that omitted the installation of polyethylene film. Sudachi was similarly stored in a heated storage (Comparative Example 1), a regular forced-air refrigerator (Comparative Example 2), and a commercially available constant-temperature high-temperature refrigerator (Comparative Example 3), and its storage condition was maintained at 2°C. Observed.

As a result of observing the sudachi stored in the storage room of Comparative Example 1, in which green tuff rock plate material was used for the side wall material of the inner cold storage room or the installation of polyethylene film was omitted, it was found that it started to deteriorate after about 10 days. It was clear that the item had no commercial value at all.

In addition, in the storage test of Comparative Example 2 in a normal refrigerator, the sudachi began to deteriorate after about 7 days, and by the 10th day it was clear that it had no commercial value at all.

Furthermore, the sudachi in the storage test in a constant temperature and high humidity refrigerator of Comparative Example 3 started to deteriorate after 30 days, and although the rate of deterioration was slower than that of the sudachi of Comparative Examples 1 and 2, it deteriorated after 40 days. It was recognized that there was no commercial value at all.

On the other hand, the preserved Sudachi in the storage of the present invention is
Even after more than 80 days, no deterioration was observed, and the fruit remained bright, dark green, almost unchanged from when it was harvested, indicating that it had retained its original freshness. I tried it just to be sure, but there was no change in aroma or flavor from when it was first harvested. Therefore, it was confirmed that the refrigerator of the present invention can maintain the freshness of Sudachi for a long period of time. Furthermore, after storing Sudachi in this storage for more than 80 days, the ethylene concentration in the air inside the storage was measured and found to be 0. It was confirmed that the content was 1 ppm or less.

Example 2 Using the low temperature storage of the present invention having a double chamber structure prepared in Example 1, the temperature inside the inner cold storage chamber was reduced to 5° C. according to the method of the present invention.
The storage condition of 50 kg of spinach stored upright in a cardboard box in an air atmosphere with a relative humidity of 95% was observed.

In addition, for comparison, the storage of Comparative Example 1 used in Example 1 (
Comparative Example 4) and Comparative Example 2 ordinary forced air refrigerators (
Comparative Example 5) and the constant temperature high temperature refrigerator of Comparative Example 3 (Comparative Example 6)
), the storage condition of spinach stored in the same manner was also observed.

As a result of observing the spinach of Comparative Example 4, it was clear that the spinach of Comparative Example 4 had become depleted after about 4 days, the tips of the leaves were wilted, and it had no commercial value.

Moreover, the spinach of Comparative Example 5 in the storage test in a normal refrigerator deteriorated or deteriorated after about 3 days, and it was clear that it had no commercial value.

Furthermore, we also observed the spinach of Comparative Example 6 in the storage test in a constant temperature and high humidity refrigerator, and found that it became depleted around 8 days.
It was clear that it had no commercial value.

In contrast, the spinach stored in the storage of the present invention did not deteriorate even after 20 days or more, and the color remained almost the same as when it was harvested, making it clear that the original freshness was maintained. I tried it for a while, but there was no change in taste compared to when it was first harvested. Therefore, it was confirmed that spinach can be kept fresh for a long period of time according to the present invention.

Example 3 Using the low-temperature storage of the present invention with a double-chamber structure produced in Example 1, the temperature of the inner cold room was reduced to 3°C according to the method of the present invention.
In an air atmosphere with relative humidity of 95%, cut irises (variety: Murakumo) in the bud state just before flowering, flower length of 100 cm, - 100 flowers in bunches, 10 bundles, 1000 flowers in total. I stored it in an upright position. and,
The state of preservation of the flowers was observed.

In addition, for comparison, the storage of Comparative Example 1 used in Example 1 (
Comparative Example 7) and Comparative Example 2 ordinary forced-air refrigerators (
Comparative Example 8) and the constant temperature and high humidity refrigerator of Comparative Example 3 (Comparative Example 9)
) The state of preservation of the irises stored in the same way was also observed.

As a result of observing the irises of Comparative Example 7, yellowing symptoms appeared on the sheaths at the tips of the irises and on the leaf surface after about 2 to 3 days, and it was clear that the irises had no commercial value.

Furthermore, the irises of Comparative Example 8, which were stored in a conventional forced-air refrigerator, showed yellowing symptoms on the pods and leaves after 2 to 3 days, and it was clear that they had no commercial value. Furthermore, although the irises of Comparative Example 9 in the storage test in a constant temperature and high humidity refrigerator were superior to Comparative Examples 7 and 8, yellowing symptoms appeared on the pods and leaf surfaces around 10 days, and the commercial value was It was clear that it was fleeting.

On the other hand, the irises stored in the storage of the present invention are
Even after more than 20 days, no yellowing symptoms appeared on the pods or leaf surfaces, and it was clear that the plants had maintained their original condition, almost unchanged from the time of exploration. There was almost no difference in the flowering condition after the shipment from the store compared to the one drilled on the morning of the same day, both in flowering condition and shelf life. Therefore, it was confirmed that it is possible to maintain the freshness of irises for a long period of time according to the present invention.

Example 4 Using the double-chamber structure cold storage of the present invention prepared in Example 1 and according to the method of the present invention, the temperature in the inner cold storage chamber was 3°C.
1. Chrysanthemum seedlings (the variety is Nishikata Chikara) for use as cuttings for plant seedlings were stored in an air atmosphere with a relative humidity of 95%. These chrysanthemum seedlings were picked from the field and placed in 20 plastic mum pots on a shelf in the inner cold room, and 10,000 of them were stored upright in the inner cold room. The storage condition of the seedlings stored as described above was observed. Also, for comparison, the storage of Comparative Example 1 used in Example 1 (Comparative Example 10)
and the ordinary forced air refrigerator of Comparative Example 2 (Comparative Example 11
) and the constant-temperature high-temperature refrigerator of Comparative Example 3 (Comparative Example 12), the chrysanthemum seedlings were stored in the same manner and the preservation state of the chrysanthemum seedlings was observed.

As a result of observing the chrysanthemum seedlings in the storage test of Comparative Example 10, a noticeable wilting phenomenon appeared due to the influence of water transpiration from the leaf surface.
It was observed that the cuttings became unusable after 12 days.

In addition, the chrysanthemum seedlings of Comparative Example 11, which were stored in a normal forced-air refrigerator, showed a noticeable phenomenon of wilting in 12 to 14 days, probably due to the drying effect of the wind, and could not be used for cuttings at all. It has been confirmed that it is possible.

Furthermore, the chrysanthemum seedlings of Comparative Example 12 in the storage test in a constant-temperature, high-temperature refrigerator showed a wilting phenomenon, or a deterioration phenomenon, although it was milder than Comparative Examples 10 and 11, around 20 days. It was found to be unusable.

On the other hand, chrysanthemum seedlings stored in the storage of the present invention are
Even after more than 60 days, there was no wilting of the leaves, and it was observed that the leaves remained in their original state when picked from the field. Therefore, it was confirmed that chrysanthemum seedlings can be stored for a long period of time according to the present invention.

Example 5 Using the double-chamber low-temperature storage constructed in Example 1 and according to the method of the present invention, raw food for steak was stored in the inner cold room at a temperature of 1°C and in an air atmosphere with a relative humidity of 90%. Fillets of beef, each weighing 350 to 400 g, were stored naked in an IO box, and their storage conditions were observed. In addition, for comparison, the storage of Comparative Example 1 used in Example 1 (Comparative Example 13), the normal forced ventilation refrigerator of Comparative Example 2 (Comparative Example 14), and the constant temperature and high humidity refrigerator of Comparative Example 3 (Comparative Example 15), beef was stored in the same manner and the storage condition of the beef at 1°C was observed.

As a result of observing the beef in the storage test of Comparative Example 13, it was observed that the surface of the fillet turned black on the third day, and deterioration and decomposition were progressing.

In addition, the surface of the beef in Comparative Example 14, which was subjected to a storage test in a normal forced ventilation refrigerator, turned black after about 3 days, similar to Comparative Example 13, and deterioration and decomposition were observed. . From this comparative example, it was confirmed that wrapping with film is necessary for storing raw beef in a normal refrigerator.

Furthermore, in the raw beef of Comparative Example 15, which was subjected to a storage test in a constant temperature and high humidity refrigerator, the surface turned black from about the 6th day, and it was observed that deterioration and decomposition had begun.

On the other hand, raw raw beef stored in the storage of the present invention starts discoloring at a slow rate from about the 9th day, and has superior storage stability compared to Comparative Examples 13 and 14 as well as Comparative Examples 15. We were able to confirm that it is suitable for food storage.

This factor is presumed to be largely related to moisture retention in food. Table 2 below shows the rate of decrease (%) in the moisture content of raw beef over time during storage, which was measured during the experiment.

In addition, similar to the raw beef mentioned above, we conducted a storage test on the shortcake at 10C and measured the rate of decrease (%) in the moisture content of the shortcake over time during storage.The measurement results are also shown in Table 2. Also listed.

Table-2

[Brief explanation of the drawing]

FIG. 1 is a schematic view schematically showing a vertical cross section of an embodiment of the double-chamber structure cold storage according to the present invention, and FIG. 2 is a horizontal cross section of the apparatus of the embodiment shown in FIG. FIG. 2 is a diagrammatically illustrated schematic diagram; FIG. 3 shows a side wall of the inner refrigerating chamber in the apparatus according to the embodiment shown in FIGS. FIG. 3 is a schematic illustrative view of the side surface of the side wall. FIG. 4 is an enlarged schematic diagram of a lattice-type support frame with vertical and horizontal bars for stretching and supporting a polyethylene film installed in the inner refrigerating chamber of the apparatus of the embodiment shown in FIG. FIG. FIG. 5 is a curve showing the decrease over time in the ethylene concentration of the air in the inner cold room of the low temperature storage room according to an embodiment of the present invention, compared with that in a commercially available normal refrigerator and a constant temperature and high humidity refrigerator. It is a diagram. In Figures 1 to 4, 1...inner refrigerating chamber, 2...
・Panel-like assembly forming the side wall, 2'... Rock slab, 3.
... Ceiling wall of the inner cold storage room, 4... Bottom wall of the inner cold storage room, 5... Polyethylene film, 5A... Polyethylene film support frame, 7... Outer enclosure , 8
...Space between l and 7, 12...cold air circulation device. Figure 1 Figure 2 Figure S Figure 4

Claims (1)

[Scope of Claims] 1. An interior that is capable of storing articles to be stored at low temperatures, has an opening/closing door that can keep the interior of the chamber in a sealed state and a windless state, and has a wall portion made of a material with good heat conductivity. Either the inner refrigerating room and the inner refrigerating room share the aforementioned opening/closing door, or they are provided with a separate opening/closing door, but a space is left between the inner refrigerating compartment and the inner refrigerating compartment. an outer enclosure made of a cold-insulating material that encloses the entire body; A low-temperature refrigerator with a double-chamber structure, which is arranged in a space of There it is,
At least a portion of the side wall surfaces and/or ceiling surface and/or floor surface constituting the inner refrigerating room for storing items to be stored at low temperatures are made of a material with good heat conductivity; Moreover, at least one wall of the four walls on the four sides constituting the inner refrigerating compartment, preferably two or more walls, is the whole or at least a part of the wall. is a rock slab with a thickness of 10 to 20 mm that has been cut from porous green tuff containing zeolite and whose ethylene adsorption ability has been activated by a roasting treatment to remove zeolite crystal water. The above-mentioned rock is made from a flat panel-like assembly consisting of a plurality of rock slabs joined together in the plane direction, and is used to form the wall of the inner cold storage room or a portion thereof. Of the surfaces of the flat panel-like assembly consisting of flat plates, a self-supporting rock plate surface of the panel-like assembly facing the windless air atmosphere inside the inner cold room is provided with a self-supporting structure. A thin low-density polyethylene film with an average thickness of 15 to 25 micrometers, stretched and supported by a support frame, is placed in contact with the rock slab surface of the panel-like assembly to cover the entire rock slab surface, and Agricultural products, flowers, plant seedlings, bulbs or foods, characterized in that the support frame supporting the polyethylene film is removably attached to the inner cold room by a removable fixture. A double-chamber cold storage facility for storage. 2. Of the total area of the inward-facing surfaces of the walls of the inner refrigerator compartment, the surfaces of the rock slabs of the panel-like assembly made of cut-out green tuff rock slabs that are in contact with the low-density polyethylene film. The total area occupied by the inward-facing surfaces of the rock slabs that are in contact with the inner cold storage chamber is such that the total area occupied by the inward-facing surfaces of the rock slabs that they touch will reduce the ethylene concentration in the air atmosphere inside the inner cold storage room after one and a half days from when agricultural products, flowers, plant seedlings, bulbs, or food products are stored. The area is sufficient to adsorb and remove ethylene to maintain it at 0.1 ppm or less, and the other wall parts of the inner cold room and the wall of the outer enclosure are made of gas-impermeable or poorly permeable material. A storage according to claim 1, wherein the storage is constructed of a material. 3. The refrigerator according to claim 1, wherein each of at least two of the four side walls of the inner refrigerating compartment is entirely constituted by a panel-like assembly made of the rock flat plate. 4. The thickness of the green tuff rock slab used is 10 mm ~
20 mm and the average thickness of the low density polyethylene film is in the range of 15 to 25 micrometers. 5. An exhaust pipe with an on-off valve for discharging air from the space between the inner refrigerating room and the outer enclosure that surrounds and accommodates it, and from the atmosphere around the outer periphery of the main storage. 2. The refrigerator according to claim 1, further comprising an air suction pipe with an on-off valve for taking in air, which is attached to the outer enclosure. 6. An inner refrigerating room that can store items to be stored at low temperatures, is equipped with an opening/closing door that can keep the interior of the room airtight and airtight, and has a wall portion made of a material with good heat conductivity; The inner refrigerating room may share the above-mentioned opening/closing door or be provided with a separate opening/closing door, but a space may be left between the inner refrigerating room and the inner refrigerating room to enclose the entirety of the inner refrigerating room. an outer enclosure made of a cold and heat insulating material; and an outer enclosure mounted inside the outer enclosure and disposed in the space between the inner refrigerating compartment and the outer enclosure. and a cold air circulation device that circulates cooling air within the space to cool the entire inner refrigerator compartment from the outside of the refrigerator compartment,
At least a portion of the side wall surfaces and/or ceiling surface and/or floor surface constituting the inner refrigerating room for storing items to be stored at low temperatures are made of a material with good heat conductivity; Moreover, at least one wall of the four walls on the four sides constituting the inner refrigerating compartment, preferably two or more walls, is the whole or at least a portion of the wall. A rock slab with a thickness of 10 to 20 mm that has been cut from porous green tuff containing zeolite and whose ethylene adsorption ability has been activated by roasting to remove zeolite crystal water, or this rock. The above-mentioned rock slab is made from a flat panel-like assembly consisting of a plurality of flat plates joined together in the plane direction, and forms the wall of the inner refrigerating chamber or a portion thereof. A self-supporting support is provided on the rock slab surface of the panel-like assembly which faces the windless air atmosphere inside said inner cold room. A thin low-density polyethylene film with an average thickness of 15 to 25 micrometers, stretched and supported by a frame, is placed in contact with the rock slab surface of the panel assembly to cover the entire rock slab surface; A double-chamber structure cold storage is used in which the above-mentioned support frame supporting the polyethylene film is removably attached to the inner refrigerating chamber by a removable fixture, and the inner refrigerating chamber of the low-temperature storage is After harvesting, fresh agricultural products, flowers, plant seedlings, bulbs, or fresh foods are stored in the refrigerator, and the inner refrigerator is closed to prevent ethylene gas generated from the stored agricultural products, flowers, plant seedlings, bulbs, or food. and carbon dioxide gas is removed from the windless air atmosphere in the inner refrigerator compartment by adsorption by the rock slab through the polyethylene film, and the gas adsorbed on the rock slab is transferred between the inner refrigerator compartment and the outer refrigerator compartment. The air containing ethylene gas released into the circulating cooling air is discharged from the exhaust pipe attached to the outer enclosure. This maintains an extremely low ethylene concentration in the inner refrigerating chamber, but prevents water vapor from escaping from the inside of the inner refrigerating chamber to the outside. The agricultural products and flowers are grown in an air atmosphere with little or no air protection, without wind, when the relative humidity of the air atmosphere is within the range of 80 to 95%, and the temperature is within the range of -3°C to +12°C. A low-temperature storage method characterized by storing plants, plant seedlings, bulbs, or foods. 7. Agricultural products to be stored include vegetables such as leafy vegetables, root vegetables, and fruits; flowers include cut flowers in the bud or blooming state just before blooming, or flowering trees such as cherry blossoms, peaches, and plums; plant seedlings include Chrysanthemums and carnations, etc.; bulbs include lilies, freesias, and collars; foodstuffs include raw meat, ham,
The method according to claim 6, which is cake, noodles, wine, etc.