JPH02273119A - Apparatus for replacing gas of container for transporting agricultural product - Google Patents

Abstract

PURPOSE:To continuously carry out preregularization atmosphere control(PRAC) treatment in a small capacity and improve productivity by connecting the first vacuum chamber having a taking in port of containers for transporting agricultural products to the first gas discharging device and the second vacuum chamber to the second gas discharge device for vacuum cooling and further the third vacuum chamber equipped with a discharging port of the containers to the third gas discharge device and gas feeder. CONSTITUTION:Respective chambers (1a), (1b) and (1c) equipped with belt conveyors 4 for conveying containers 3 for transporting agricultural products therein are connected with the respective first and second valves (2a) and (2b) and the preparation chamber (1a) is equipped with a taking in door 19 for the containers 3 and connected to a vacuum pump (6a). The vacuum cooling chamber (1b) is then connected to a vacuum pump (6b) for vacuum cooling and the gas introduction chamber (1c) is provided with a means for closing a discharging door 20 and openings of the containers 3 and connected to a gaseous carbon dioxide gas cylinder (14a) and a nitrogen gas cylinder (14b). The PRAC treatment can be continuously carried out in a small capacity by using the above-mentioned construction to improve productivity.

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to an apparatus that continuously processes fresh agricultural products immediately after harvest to maintain their freshness. [Conventional techniques and their problems] Fresh agricultural products such as vegetables and fruits rapidly deteriorate due to physiological metabolism such as respiration that continues even after they are harvested. Generally known methods include ``precooling,'' which rapidly lowers the temperature of agricultural products to suppress physiological metabolism such as respiration, and ``refrigeration,'' which continues to maintain low temperatures after precooling. Precooling methods include the following: a) Forced draft pre-cooling: The produce is pre-cooled by circulating cold air cooled by a heat exchanger in a container containing fresh produce. b) Differential pressure (ventilation) pre-cooling: A method in which cold air cooled by a heat exchanger is passed and circulated between stored produce with a slight pressure difference.This method is more efficient than forced draft pre-cooling. C) Vacuum precooling: Evaporating water from the produce by applying a vacuum, and precooling the produce by the heat of evaporation as the water evaporates. d) Cold water precooling: Precooling the produce by pouring cooling water over the produce. Among the above methods, method a) requires half a day to one day for the temperature of the produce to cool from room temperature to the desired temperature (2°C to 5°C). According to the b) method, it cools down in 3 to 6 hours, which is shorter than the a) method, but it is time-consuming because the produce must be placed in a special way when stored in a container. Method d) requires a shorter cooling time than method b), but it is rarely practiced in Japan because water gets on the produce, causing spoilage after cooling. The present inventors have developed several methods that combine the vacuum precooling method, which is the most effective of the methods a) to d) above, with a storage and transportation system using PRAC treatment, which can further suppress the physiological metabolism of agricultural products than refrigeration. I have suggested something. PRAC processing (PRAC is PreRegu)
larization At5osphere Con
Trol (abbreviation for trol) is an airtight container whose opening in the wall is closed with a membrane that is selectively permeable to gas.The container is filled with agricultural products, vacuum cooled, and returned to atmospheric pressure when carbon dioxide or nitrogen gas is released. After introducing gas or a mixture thereof, the chamber is sealed. In the case of certain types of silicone membranes used as gas-selective permeable membranes, the amount of permeation of carbon dioxide and ethylene is much greater than the amount of permeation of oxygen. While ensuring the minimum amount of oxygen necessary for breathing, it is possible to remove the aging and damage caused by ethylene and carbon dioxide gas generated by agricultural products. Furthermore, according to the PRAC storage and transportation system, the freshness of agricultural products can be maintained several times longer than with conventional refrigeration storage and transportation. However, since a vacuum container and a refrigerator must be provided, there is a drawback that the cost of the apparatus is high. Furthermore, if the agricultural products are currently in small quantities (10 to 100K)
g) Put the produce into a plastic bag with holes punched in advance,
The method used is to vacuum cool the material, introduce gas, and then close the holes with tape or the like after taking it out of the processing equipment. In the case of large capacity (100Kg to 5t), place the produce in a PRAC processing container (an opening in the wall of an airtight container sealed with a gas selectively permeable PRAC membrane) and leave the lid slightly open. After vacuum cooling and gas introduction, the container is removed from the processing equipment, the container is pulled out, and the lid is closed. With these methods, if the volume is small, it takes time and effort to drill and close the holes. Furthermore, in the case of a large capacity, there is a problem in that it takes time and effort to handle the container, and processing cannot be performed unless a certain amount is collected.

[Problems to be solved by the invention]

The present invention has been made in view of the above-mentioned problems, and is
It is an object of the present invention to provide a gas replacement device for a container for transporting agricultural products that can perform AC processing continuously in a small capacity and improve productivity. [Means for Solving the Problems] The above object consists of a first vacuum chamber, a second vacuum chamber, and a third vacuum chamber, each of which is equipped with a transport means for transporting a container for transporting agricultural products; The vacuum chamber and the second vacuum chamber are connected through a first valve, the second vacuum chamber and the third vacuum chamber are connected through a second valve, and the first vacuum chamber is connected to the agricultural product transporter. The second vacuum chamber is connected to a second exhaust device for vacuum cooling, and the third vacuum chamber is connected to an exit port for containers for transporting agricultural products. , a means for closing at least one opening provided in the container for transporting agricultural products, and the container is connected to a third exhaust device and a gas supply device. This is achieved by a displacement device. [Function] According to the gas displacement device for a container for transporting agricultural products configured as described above, a small-capacity vacuum container is sufficient, so the costs of the refrigerator and vacuum container are low. In addition, it can handle any capacity and can be processed continuously.Furthermore, the work of drilling and sealing holes each time PRAC processing is performed in a vacuum.Productivity is further improved. [Example] Hereinafter, an example will be described with reference to the drawings. Fig. 1 is a sectional view schematically showing a gas replacement apparatus for continuously performing PRAC processing. In Figure 1, (L is the preparation room, (ribs) are the vacuum cooling room,
(lc) is a gas introduction chamber, both of which have pressure resistance and airtightness that can withstand vacuum. (19) is a container (3) containing agricultural products (see Figure 2)
An airtight carry-in door (20) is provided in the preparation room (la) for carrying in the gas, and (20) is an airtight carry-in door provided in the gas introduction chamber (lc). Preparation room (1a) and vacuum cooling room (lb)
A valve (2a) through which a container (3) can pass is installed between the vacuum cooling chamber (LB1) and the gas introduction chamber (LBL).
(2b) is attached. In addition, a belt conveyor (4) for transporting containers (3) is installed in the preparation room (L), vacuum cooling room (German), and gas introduction room (Soldier). Vacuum pump (6a) via valve (2e)
It is also equipped with a leak valve (13). (5) is a cold trap, which has pressure resistance and airtightness that can withstand vacuum, and is connected to the vacuum cooling chamber flb). The cold trap (5) is connected to a vacuum pump (6b) via a valve (2c), and a drain valve (7) is attached to the bottom of the cold trap (5). There is a heat exchanger (
8) is piped. The heat exchanger (8) is connected to the brine tank (2d) via the brine circulation pump (9) and the valve (2d).
10). A heat exchanger [11] is piped inside the brine tank (10), and a refrigerant (for example, Freon R22) cooled by a refrigerator (12) is circulated through this. The brine tank (10) is filled with brine (e.g. ethylene glycol), which is cooled by a heat exchanger (11), passes through a brine circulation pump (9), and is heated via a valve (2d). Exchanger (8
). The gas introduction chamber (soldier) is connected to a vacuum pump (6) via a valve (2f).
c). In addition, an air intake valve (15) is attached to the gas introduction chamber (soldier), and an additional valve (2h
), and a nitrogen gas cylinder (14b) is connected through a valve (2g) and a carbon dioxide gas cylinder (14a), respectively. There is also an opening (23) in the gas introduction chamber (3) of the container (3).
) and a roll [18) wrapped with an airtight adhesive tape (17) to be applied to the container (3), and a pressing machine (1) to cut the adhesive tape (17) and press it against the opening (23) of the container (3).
6) is installed. Although not shown, the roll (1
8), the press 11 (16) automatically moves up and down when the container (3) comes to a certain position. Details of the container (3) for storing agricultural products are shown in Figure 2. The main body of the container (3) is made of an airtight material. A gas selectively permeable PRAC membrane (22) is pasted on at least one opening provided on the wall surface (21).The wall surface (21) is further provided with an opening (23). During vacuum cooling, the water vapor that has taken away the latent heat of vaporization from the produce is exhausted from here.The lid (24) of the container (3) is
After storing the agricultural products inside, it is closed with airtight tape (25). Next, operations for continuously performing PRAC processing using the above-mentioned apparatus will be explained step by step. l) Store the produce in the container (3) and close the lid (24) with tape (25). 2) Loading! 'l (19), Export 1! (20), valve (
2al (2c) (2dl(2e) (2f) (2
g) (2hl (7) (13) (close 151,
Open valve (2b). 3) Open the valves [2c] (2f) and turn on the vacuum pump (6b).
6c) to bring the inside of the vacuum cooling chamber (rib) and gas introduction chamber (arm) to a predetermined pressure (approximately 4 to 6 Torr). 4) Open the valve (2d) and operate the refrigerator (12) and brine circulation pump (9). The cooled brine in the brine tank (10) circulates in the heat exchanger (8). 5) Open the loading door (19) and place the containers (3) inside the preparation room (L).
). 6] Loading! n (19) and open the valve (2e) to operate the vacuum pump (6a). 7)1! Preparation room (within the specified pressure (4 to 6 Torr)
When the temperature reaches the desired temperature, the valve (2a) is opened and the container (3) is sent into the vacuum cooling chamber (rib). 8) Close valves (2a) and (2e) and open valve (13) to return the preparation chamber (la) to atmospheric pressure. 9) Repeat operations 5) to 8). 10) Moisture in the produce stored in the container (3) in the vacuum cooling room (tb) turns into water vapor, absorbs latent heat of vaporization from the produce, is discharged from the opening (23), and is vaporized in the cold trap (5). Trapped. Ethylene, which has the effect of accelerating aging and ripening of agricultural products, is also discharged from the container (3). The speed of the belt conveyor (4) is adjusted so that the produce cools to the desired temperature while the containers (3) move from one end of the vacuum cooling chamber (ribs) to the other. 11) Once the produce in container (3) has cooled down sufficiently. Transfer the volume i% (3) to the gas introduction chamber (embryo). 12) Close the valves (2bl (2f)). 13) Open the valves (2g) (2h) (Is) and inject the prescribed amounts of nitrogen gas, carbon dioxide gas, respectively, until the gas introduction chamber (red) reaches atmospheric pressure. Introducing static electricity. Due to the action of the gas, the respiration or physiological metabolism of the produce in the container (3) is maintained to be minimal and normal. ! 4) When the gas introduction chamber (lc) reaches atmospheric pressure, move the press 1111B) and close the opening (23) of the container (3) with the adhesive tape (17). Adhesive tape will be cut automatically. Is) Close the valve (2g) (2h) (ts) and unload 1
Open 1 (20) and take out the container (3). 16) Close the unloading Hjg (20) and open the valve (2f) to evacuate the inside of the gas introduction chamber. 17) The inside of the gas introduction chamber (b) has a predetermined pressure (4 to 6 Torr).
When the temperature reaches approximately r), open the valve (2b). 18) Perform the operations from 5) to 17) on the container (3) to be processed.
) repeat until all are completed. 19) When the work is completed, close the valves (2e) (2c) (2f
Close l, open valve (13) (2b) (Is),
Return the preparation room (L), vacuum cooling room (rib), and gas introduction chamber (red) to atmospheric pressure, stop the refrigerator (12), and heat exchanger (8).
) and remove the water from the drain valve (7). The embodiments of the present invention have been described above, but of course the present invention is not limited thereto, and various modifications can be made based on the technical idea of the present invention. For example, although a brine refrigerator was used in the embodiment, a direct expansion type refrigerator may also be used (in that case, the cost of the refrigerator would be a little lower). Although only one line has been explained in the embodiment, multiple lines may be connected in parallel as shown in Fig. 3. In Fig. 3, parts corresponding to Fig. 1 are the same. shall be marked with the symbol. Or, for other systems, a dash shall be added. Further, in the example, a container with an opening (23) provided in advance was used, but it is also possible to use a container without an opening and make a hole automatically when the container enters the preparation room (la). I do not care. Various methods can be considered as means for closing the opening in the gas introduction chamber. In the example, adhesive tape was pressed, but
Alternatively, a piece of adhesive tape of a predetermined size may be vacuum-adsorbed and then sprayed onto the adhesive tape. Also, P with a lid can be used as a container.
When a RAC processing container is used, a means may be provided to place the container in the preparation chamber with the lid slightly shifted and to properly fit the lid in the gas introduction chamber. (Effects of the Invention) Since the present invention is configured as described above, it has the following effects.According to the present invention, the preparation chamber and the gas introduction chamber have space for storing at least two containers. Moreover, once the vacuum cooling chamber is evacuated, it is maintained as it is during work, so unlike conventional PRAC processing equipment, the vacuum chamber and refrigerator can be smaller, reducing the cost of the equipment. , it can handle any volume of agricultural products and can be processed continuously.Furthermore, since the operation of closing the opening is done automatically in the gas introduction chamber, it not only has the effect of saving one labor; Since the container is sealed in a nearly sterile state, there is less chance of mold or bacteria forming on the produce.

[Brief explanation of drawings]

Fig. 1 is a schematic cross-sectional view of a gas replacement device for continuously performing PRAC treatment according to an embodiment of the present invention, Fig. 2 is a perspective view of a container used in the embodiment, and Fig. 3 is a modification of the present invention. FIG. 2 is a schematic cross-sectional view showing an example gas replacement device. In addition, in the figure, lal...... Preparation room U)...
......Vacuum cooling chamber 1c) --Gas introduction chamber 2a) (2b)...Valve 3)...
・・・・・・・・・Container 4)・・・・・・・・・
...-Belt conveyor 6a) f6b) (6cl
==・Vacuum pump 14a)・・・・・・・・・・・・
Carbon dioxide gas cylinder 14b)・・・・・・・・・・・・Nitrogen gas cylinder 16)・・・・・・・・・・・・・Press
Attachment machine 17)・・・・・・・・・Adhesive tape 18)・・・・・・・・・・・・Roll (19)・・・・・・・・・・・・・・・ (20)・・・・・・・・・・・・

Claims (1)

[Claims] It consists of a first vacuum chamber, a second vacuum chamber, and a third vacuum chamber, each of which is equipped with a transport means for transporting a container for transporting agricultural products, and the first vacuum chamber and the second vacuum chamber each have a first valve. the second vacuum chamber and the third vacuum chamber are connected via a second valve, the first vacuum chamber is provided with an entrance for the container for transporting agricultural products, and the first vacuum chamber is connected to a first exhaust device. the second vacuum chamber is connected to a second evacuation device for vacuum cooling, and the third vacuum chamber is connected to an outlet of the agricultural product transport container and at least one opening provided in the agricultural product transport container. 1. A gas replacement device for a container for transporting agricultural products, characterized in that the device is connected to a third exhaust device and a gas supply device.