JPS63219338A - Process for vacuum precooling of vegetable, or the like and apparatus therefor - Google Patents

Abstract

PURPOSE:To release air in a cold-reserving box placed in a vacuum chamber and containing an object to be reserved in cold state and to automatically inhibit ventilation under atmospheric pressure, by forming a small ventilation hole to a proper part of a cold-reserving box to release the air in the box. CONSTITUTION:A small ventilation hole having a smallest possible diameter to enable the release of air from a container 2 in evacuated state is formed at a part of a main body 2 of a container made of foamed synthetic resin and used in vacuum- precooling and/or a lid 3 attached to the main body in a manner to keep air-tight state. An object to be reserved in cold state is put into the vacuum cold-reserving box 1 having the above structure and the box 1 is placed in a vacuum chamber 9. Air in the cold-reserving box 1 is released through the hole 6 and the box is evacuated according to the deaeration in the vacuum chamber 7 to cool the object to be cooled. When the space in the vacuum chamber 7 is returned to atmospheric pressure, the intrusion of air into the box is automatically inhibited by the ventilation resistance generated in the ventilation hole 6. The cooled state in the cold-reserving box can be maintained while minimizing the influence of outer atmosphere and the object is kept in fresh state over a long period.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention prevents damage to a box housing the objects to be cooled and facilitates depressurization when precooling objects to be cooled such as vegetables and fruits in vacuum. The present invention also relates to a vacuum precooling method for vegetables, etc., which prevents outside air from entering a cold storage box taken out of a vacuum chamber, and an apparatus therefor.

[Conventional technology]

Conventionally, as a method for cooling and keeping objects to be kept cold, such as vegetables and fruits, a container body and a lid made of expanded polystyrene are used, and the objects to be kept cool are placed inside the container in a vacuum chamber. The air inside the container is degassed in a vacuum chamber through the suction opening provided on the side wall of the main body or through the communication hole provided in the fitting part of the container main body and the lid, thereby deaerating the inside of the container to a level of, for example, several Torr. There is a method of cooling the object stored in a container to a low temperature of, for example, 0° C. to 10° C., keeping the object cold, and transporting it from the production area to the consumption area while maintaining its freshness.

[Problem that the invention seeks to solve]

However, these cold boxes used for vacuum precooling and these vacuum precooling methods create a vacuum by degassing the inside of the vacuum chamber, and at the same time create a vacuum inside the container through the openings and communication holes of the cold box to keep the product cold. However, because the diameter of these openings and communication holes is large, outside air tends to enter when the cold storage box is removed from the vacuum chamber with the items to be kept inside, stored or even transported. The effects of temperature and oxygen on the refrigerated items are detrimental to long-term freshness maintenance. In addition, when attempting to close these openings or communication holes, it takes time and effort to close them, which increases costs and also causes outside air to enter, making it impossible to achieve the effect of vacuum precooling. In view of the vacuum pre-cooling method using such a cold box, vacuum cooling is performed by barely making it possible to degas the cold box containing the objects to be cooled in the vacuum chamber due to the pressure difference between the inside and outside. The object of the present invention is to provide a vacuum precooling method using a cold box in which the communication holes inside and outside have small diameters, making it difficult for outside air to enter due to the ventilation resistance, and minimizing the influence of outside temperature.

[Means for solving problems]

In order to achieve the above object of the present invention, the present invention provides a foamed synthetic resin container body used for vacuum precooling and/or a lid body attached to maintain an airtight state. The object to be cooled is housed in a vacuum precooling cooling box provided with ventilation pores of the minimum diameter through which air flows out, and the object is placed in a vacuum chamber. It is an object of the present invention to provide a vacuum precooling method for vegetables, etc., which is obtained by cooling vegetables through degassing and vacuuming, and also to provide a cold storage box for use in this method.

[Details of the invention]

That is, the vacuum pre-cooling method for vegetables, etc. according to the present invention uses a vacuum pre-cooling cold storage box 1 different from that used in the conventional vacuum pre-cooling method, and performs vacuum pre-cooling of vegetables, etc. while taking advantage of the structural characteristics of this box. It is something.

That is, the container body 2 made of foamed synthetic resin used for vacuum precooling is made of a suitable material such as foamed polystyrene, foamed polyurethane, foamed polyethylene, etc.
Alternatively, the lids 3 that can be fitted with each other are installed while maintaining an airtight state by engaging the protrusions 4 protruding on the lower surface as shown in the illustration with the recesses 5 provided on the upper surface of the mouth edge of the container body 2. Vegetables, fruits, etc. to be kept cool are placed in a cold box 1, which has ventilation holes 6 at appropriate locations on a lid 3 made of foamed synthetic resin similar to the container body 2, which allows the air inside the cold box 1 to escape. As shown in FIG. 1, a large number of cold storage boxes 1 containing objects to be cooled are stacked and installed in a vacuum chamber 7, and then the inside of the vacuum chamber 7 is rapidly degassed using a vacuum device 8. By this,
As the vacuum chamber 7 is evacuated, the air pressure inside the vacuum chamber 7 suddenly becomes lower than the air pressure inside the cold storage box 1 containing the object to be cooled, resulting in a pressure difference. While moving air into the vacuum chamber 7 through the ventilation holes 6 provided in the lid body 3, the vacuum chamber 7 is evacuated in the same way as the inside of the vacuum chamber 7, and the inside of the cold storage box 1 is evacuated and the vacuum is applied to the objects to be refrigerated. Depending on the condition, moisture is evaporated from the surface of the object to be kept cool to pre-cool vegetables, etc. under vacuum.

Here, the vacuum precooling cold storage box 1 for storing the objects to be cooled may have, for example, round holes, square holes, or slits of an appropriate size, and at least when the chamber is evacuated, the cold storage box 1 is heated by the differential pressure. The air inside the box flows out elastically to the outside against the resistance created in the pores (hereinafter referred to as ventilation resistance), but when the cold storage box is returned to atmospheric pressure, the air inflow increases the ventilation resistance in the pores. Ventilation pores 6 are provided with a size that makes it difficult for air to flow into the air. Such ventilation pores 6 have a width or diameter smaller than one-fifth of the wall thickness, and since the wall thickness is usually 30 to 40 mo+, the width or diameter is 8 m.
By opening one or more through holes with a width or diameter of 0.5 m or less, preferably 0.5 to 3 m, when the cold box 1 is installed in a vacuum in the vacuum chamber 7, the ventilation pores are opened. 6, the air in the cold box 1 is degassed and precooled in vacuum. After the vacuum precooling is completed, when the vacuum chamber 7 is taken out for transportation and returned to atmospheric pressure, air flows inside the cold box 1 due to the pressure difference between the inside and outside of the cold box 1. However, the ventilation resistance caused by the ventilation pores 6 makes it difficult for air to circulate, so a closed airtight state is maintained. and,
During transportation, if this condition is maintained, it will be possible to maintain the cooling for a long period of time, maintain the freshness of the items to be refrigerated such as vegetables and fruits, prevent damage to the cold box 1, and reduce the effects of outside air intrusion. Uchino is reduced as much as possible.

Next, an example of the vacuum precooling cold storage box used in the present invention will be described.

Embodiment 1 What is shown in Fig. 2 and below is an example of the cold storage box 1. In the figure, 2 is the container body, 3 is the lid, and both members maintain an airtight state with each other at their abutting portions. In the illustrated example, a fitting relationship is provided such that
1 mm in diameter at the side wall 10 and bottom wall 9 of the container body 2
It is provided with ventilation pores 6 of approximately As shown in FIGS. 2 and 3, the ventilation holes 6 allow outflow or make inflow difficult depending on the pressure difference between the inside and outside of the cold storage box 1.

That is, by providing a plurality of ventilation holes 6 at appropriate locations in the side wall 10, bottom wall 9, or lid 3 of the container body 2, vegetables, fruits, etc. to be kept cool can be stored in the cold box l. When it is placed in the vacuum chamber 7 and evacuated by the vacuum device 8, the air pressure inside the vacuum chamber 7 becomes lower than the air pressure inside the cold storage box 1, and the air inside the box flows into the vacuum chamber 7 through the ventilation holes 6. The inside of the box is degassed and vacuumed to cool it down. When trying to take out the cold box 1 from the vacuum chamber 7, the chamber 7 is returned to atmospheric pressure. The airflow resistance at the time of inflow prevents the air from flowing through the ventilation pores 6, thereby minimizing the influence of outside air and outside temperature. 4 and 5 are perspective views of a lid representing another embodiment, and show a case where a square hole or a slit of an appropriate size is provided as the ventilation hole 6 as described above. It is something. Furthermore, since the cold storage boxes 1 are stacked in multiple stages with objects to be kept cool inside, a top plate is provided so that the air flowing out from the ventilation holes 6 in the stacked state can be easily vented to the outside of the cold storage boxes 1. A protrusion 12 is provided on the periphery of the upper surface of 11, and a ventilation groove 13 is formed adjacent to the protrusion 12.

Furthermore, as shown in FIG. 6, a thin wall portion 14 that can be broken due to the pressure difference between the inside and outside of the cold box 1 caused by a vacuum is inserted into the ventilation hole 6 without opening the ventilation hole 6 in advance as shown in the figure. When the cold box 1 is placed in the vacuum chamber 7 and evacuated by the vacuum device 8 as described above, the air pressure inside the vacuum chamber 7 becomes lower than the air pressure inside the cold box 1. The air inside the cold box 1 is sucked in order to cool the cold box 1.

That is, since it is pressed outward from the inside of the cold box 1 in the direction of the arrow in the figure, part or all of the thin wall portion 14 is pressed against the imaginary line 14 in the figure.
The box is broken as indicated by ' or 14' to open the ventilation hole 6, and the air inside the box is allowed to flow out through the ventilation hole 6 to degas and vacuum the inside of the box, thereby cooling the box. When the vacuum chamber 7 is returned to atmospheric pressure, air tries to flow into the cold box 1 through the ventilation holes 6 as before, but the thin wall portion 14 is broken.
' or 14'' acts as a check valve and prevents ventilation in addition to the ventilation resistance, thereby further minimizing the influence of outside air and outside temperature.

〔Effect of the invention〕

As described above, according to the vacuum precooling method for vegetables, etc. and the device thereof according to the present invention, ventilation holes are provided at appropriate locations in the cold storage box for escaping the air inside the cold storage box. When the cooled items stored inside are vacuum degassed for cooling, the air inside the container is released to the outside against the ventilation resistance of the ventilation pores due to the difference between the pressure inside the cold storage box and the pressure inside the chamber. In addition, when the inside of the vacuum chamber is returned to atmospheric pressure, ventilation is automatically blocked by the ventilation resistance generated by the ventilation pores, and the cooling state inside the cold storage box is maintained while minimizing the influence of outside air. It provides an environment for maintaining freshness for a long period of time for items to be refrigerated. Further, even during transportation, outside air will not enter into the cold storage box through the opening, and furthermore, the container body will not be damaged in the vacuum chamber.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram showing a vacuum precooling system, Fig. 2 is an explanatory cross-sectional view of a cold box, Fig. 3 is an explanatory perspective view of the cold box, and Figs. 4 and 5 show other embodiments. FIG. 6 is an explanatory perspective view of the lid body, and FIG. 6 is an enlarged cross-sectional view of the main part showing a state in which a thin wall portion is formed in the ventilation hole. 1: Cold box, 2: Container body, 3: Lid, 4: Projection, 5: Recess, 6: Ventilation pore, 7: Vacuum chamber, 8: Vacuum device, 9: Bottom wall, 10: Side wall , 11: Top plate, 12: Projection, 13: Ventilation groove, 14: Thin wall portion. Figure 6 Figure 2 Figure 1 Figure 4 Figure 51 Figure 3-Figure

Claims (1)

[Claims] 1) A foamed synthetic resin container body used for vacuum precooling and/or
Alternatively, the object to be refrigerated is housed in a vacuum pre-cooling refrigerator box, which has ventilation holes of the minimum diameter through which the air inside the container flows out when the container is set in a vacuum state, on the lid that is attached to maintain an airtight state. A vacuum precooling method for vegetables, etc., which is installed in a chamber, and is cooled by degassing and vacuuming the cold box through the ventilation holes as the vacuum chamber is degassed. 2) The vacuum precooling method for vegetables, etc., according to claim 1, which uses round holes as the ventilation holes. 3) A vacuum precooling method for vegetables, etc., according to claim 1, which uses slits as ventilation holes. 4) Vegetables, etc. according to claim 1, 2, or 3, which utilize pores having a width or diameter smaller than one-fifth of the thickness of the wall as the ventilation pores. vacuum precooling method. 5) Vacuum precooling in which the foamed synthetic resin container body used for vacuum precooling and/or the lid that is attached to maintain an airtight state are provided with ventilation holes that allow the air inside the container to escape when the container is set in a vacuum state. Cold storage box device.