NO802787L - PROCEDURE AND APPARATUS FOR STORAGE AND CONSERVATION OF PRODUCTS THAT CAN BE SPECIAL, SPECIAL FOODSTUFFS - Google Patents

Description

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The present invention relates to a method

for the preservation and conservation of perishable products, especially foodstuffs, using liquefied gas as a refrigerant. The method, according to the invention, is particularly suitable! for the preservation and preservation of fruit,

■vegetables, meat, j poultry, dairy products, plants, flowers, chocolate goods etc. , which can spoil under the influence of the air oxygen>temperature in the environment and finally the microorganisms sbm are present in the product, respectively in the surrounding mecilium.

Furthermore, the invention relates to a device for carrying out the method, as well as a sluice system cooperating with the device.

It is known that the chemical processes that

runs in perishable foodstuffs, processes such as e.g. in living plant parts which, change of substance, is the greater*» more delayed the lower the temperature. As the optimum temperature for the growth of most microorganisms lies between + 25 and + 35^C, this microorganism growth can by reducing the temperature during transport and storage,

completely or partially prevented (refrigerated storage, freezer storage).

Furthermore, it is known that with the help of a suitably controlled or regulated atmosphere, especially with a greatly reduced oxygen content, shelf life can be achieved for fruit and other things stored in a cold room for a longer period of time, e.g. up to several months. In the case of fruit such as apples, as is well known, certain life functions also occur after harvesting, where oxygen is consumed and carbon dioxide is formed. The faster this respiration takes place, the faster the fruit ages.

This breathing intensity can be reduced, and thereby the shelf life can be increased when the oxygen concentration in the storage atmosphere is reduced and the carbon dioxide concentration is increased. These known facts are used e.g. , by so-called gas-cold storage, which has proven to be very beneficial for cold-sensitive apple types.

However, the hitherto known methods for the preservation and conservation of perishable foodstuffs and other perishable products show serious shortcomings. The transport and storage of such products requires the use of cooling or freezing units, which entail very high initial investments and which must be maintained on an ongoing basis. When stopping I of a cooling aggr^j<g>at<,>e.g. by a

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refrigerated transport meat, the entire load is often so affected in quality that it cannot be cured. The stationary cold houses, and especially the C02 stores, can only be filled respectively

is completely emptied at once, so that:'there is none left

possibility to store or pick up special different goods at convenient times.

The present invention has the task of

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overcome the shortcomings of these known methods, and that using liquefied gases as refrigerant.

It has been found that by meåt. possible uninterrupted maintenance of an atmosphere with, in terms of temperature and composition, regulated, the products stored and/or transported therein and especially even easily perishable products can maintain their optimal condition for a surprisingly long time.

The object of the invention is thus a method for the preservation of perishable products, especially foodstuffs, using liquefied gases as a refrigerant, and this method is characterized by bringing the perishable products, possibly

after pre-storage under controlled atmosphere, to a closed

bare and completely insulated container, and in this, by controlled blowing in of liquefied gas, creates an atmosphere controlled with regard to temperature and composition in the gas mixture, and if necessary, the products are subjected to subsequent storage in order to further maintain the

controlled atmosphere.

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Of significant importance; is within the framework of the method of the invention, the1 most possible uninterrupted maintenance of the regulated atmosphere, and tempera-

the trip practically from harvesting or storage and during all transport until withdrawal from the warehouse, possibly until immediately before consumption of the goods.

Hereby, it turns out to be particularly advantageous to be able to continuously maintain both the optimum temperature for what is in the container, and also to maintain the optimum composition for the gas mixture.

For the practical execution of the method, according to the invention, it has proven advantageous to control the blowing in by means of a device near the container lid

and the container bottom arranged-temperature sensor, and by means of

of a sensor that measures the oxygen or gas content. The temperature of the products that are brought into the container

and the surrounding storage atmosphere, can thus be set in a simple way to any desired value within a range of preferably - 10 to + 20°C. an atmosphere that works against the processes that can take place in products that are in the warehouse.

Depending on the product to be brought into the container, the temperature and gas composition in the container space are regulated differently. It has also proven advantageous to maintain the relative humidity in the container space at the optimal value at all times to counteract weight loss and the risk of products wilting or shrinking.

In the method according to the invention, can

especially fruit and vegetables, e.g. apples, pears, strawberries, cherries, peaches, southern fruits, bananas, potatoes, lettuce, tomatoes, beans, onions, cucumbers; fresh meat, fish and poultry, as well as other perishable agricultural products, such as eggs and also; flowers, are kept fresh for unexpectedly long periods of time. ! i- r

A device suitable for carrying out the method according to the invention is distinguished by the fact that it comprises a closable and completely insulated container, which in a separate compartment has a bottle battery with liquefied gases, and a storage room separated from this room for receiving the perishables products, and by the fact that there are wires

from the gas cylinders to the spray nozzle: in the storage room nearby

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of the roof, and at ij near the bottom arranged temperature sensors as well as near the container roof arranged by %-

sensor controlled valves.

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In order to maintain a regulated storage and transport atmosphere for the perishable products, using the method according to the invention, it has proved advantageous to arrange a sluice and a stationary for-,

intermediate or final storage, in which the regulated atmosphere is also maintained.

Such a s!lus<e>is distinguished according to the invention

in that it has a gas-tight closable drive-in opening for the above-mentioned container, if necessary mounted on a drivable undercarriage, an adjoining storage room with a controlled atmosphere leading to it and likewise a gas-tight closable loading opening, as well as the necessary for setting the controlled atmosphere in the lock gas bottles, fixtures and measuring <1>and regulating devices. Particularly advantageous is the further arrangement of a weight in the lock,

in order to be able to control the quantity of product entered and withdrawn.

With reference to the attached drawings and

the following examples will explain the invention in more detail.

In the drawing, fig 1 shows a section through a container according to the invention, while fig. 2 shows a lock according to the invention in plan view.

According to fig. 1, located: it is in a closed and

fully insulated container with a K-value of approx. 0.4, a battery of insulated bottles, 3, in a separate room, 2, whereby the bottles e.g. is filled with liquid nitrogen or carbon dioxide.

Behind the room department, <1>4, you will find; in the container 1, a storage room, 5, on e.g. 60m<3>where perishable products such as fruit, vegetables or meat are to be |stored. From the gas cylinder,

3, leads with the necessary fittings, equipped lines, 6, to a point near the container roof in the storage room and spray nozzles arranged there, 7. Near the container roof

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and in the vicinity of the bi eholder floor, e'■r : there are arranged temperature sensors, 8, which together with a not shown regulating device and a schematically indicated power source, e.g. a car battery, regulates an electromagnetic valve, 10. Parallel to this, there is in a I ytt■ erlier wiring<i>ing, 6, arranged one of a %-regulator, 9 / controlled valve,! 10.

Alternatively, you can in the completely insulated container

give up separate rooms for bottles and goods, and instead choose a structure where bottles and goods are stored in containers Suten room division, or where the bottles

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is arranged outside the insulated container, e.g. as a separate battery: of insulated bottles.

The effect of the device in fig. 1 is it

following: When goods to be stored or transported are brought into the storage room,5, after closing the container, the blow-out process of e.g. liquid carbon dioxide controlled via an electromagnetic valve, 10, in such a way that the set temperature" in the storage room is achieved,

using an integrated temperature-controlled system that senses the temperature in the storage room using the temperature sensor,8. In parallel with the temperature regulation, the % regulator,9, comes into action whereby, during utilization of the gaseous phase of the liquefied gas, the desired storage atmosphere, e.g. a certain C02 content in the storage atmosphere is set.

The sluice, 15 arranged according to fig.': 2, has a gas-tight closable entry opening, 11, for the container,!, possibly | arranged on a movable undercarriage.

When the container, 1, is designed as a container or truck semi-trailer, the entire cargo train can possibly be driven into the lock. From the lock, a likewise gas-tight closable filling opening, 13, leads to the to-l. storage room adjacent to the lock, possibly a stationary CC>2-storage. For control of loading and unloading, a weight, 14, can be arranged in the lock.

The lock shown is used for loading and unloading

of the container according to the invention while maintaining the regulated storage atmosphere, especially during transfer

of perishable products from a :.;om container constructed container to a fixed warehouse with a similarly regulated warehouse atmosphere. After driving the container into the lock, it becomes

in this created the necessary controlled atmosphere,

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to which there are arranged gas ratio flasks, fittings and measuring <;> and regulating bodies not shown. After the same control atmosphere has been achieved in the lock as in the adjacent storage room, the container can be filled or emptied, where after the operation is completed, the coating opening is closed and then normal atmosphere is restored in the lock, and the container is driven out of the lock.

With a device with 4 insulated 40-litre gas storage cylinders, filled with liquid C02, a fully insulated storage room of approx. 60m^■ can be kept at an internal temperature of 0 to 3°C, and a CC^- concentration in the warehouse atmosphere of about 5% for about 14 days.

Example 1.

In a standard container which - in a separate room - exhibits

a battery of insulated storage bottles, filled with liquefied nitrogen, respectively carbon dioxide, freshly harvested apples are brought in. After closing the container, via an integrated temperature-controlled system that senses the temperature at the roof and floor of the container, nitro-

gene in liquid phase via spray nozzles arranged in the ceiling. The temperature in the storage room is thereby lowered to barely above

0°C, e.g. + 0.5°C, and then.continuously held in a range of up to + 4oc by diverted blowing in of CO2.

In parallel connection with the temperature regulation, a 02% meter is arranged which, during utilization of the gas

formable phase to the liquefied carbon dioxide, regu-

continuously increases the C02 proportion I in the storage atmosphere to approx.

5% by volume. At a relative humidity of 90 to 95%, the apples show excellent quality even after a storage period of 12 months, especially in terms of colour, firmness, vitamin content and taste.

Example 2. j

The precautions mentioned in example 1 are repeated

using bulbs. The temperature is kept at +0.5°C, the CG^ concentration in the storage atmosphere is set to approx. 5% by volume. After 12 months of storage at a relative humidity of 85 to 90%, the fruit shows an unchanged good quality.

Example 3. |

In compliance with the precautions taken in example 1, peaches are stored. The temperature is kept in the range + 0.5 to + 4°C, the C02 concentration in the storage atmosphere. the distance is set to approx. 5 volunj-%. By maintaining a humidity of approx. 90 to 95% of this type of fruit can be stored for a period of 2 to 4 months without a reduction in quality.

Example 4.

According to the method described in example 1, potatoes are stored in a container. The temperature in the storage room is lowered by blowing in liquid nitrogen to + 4 to + 7°C and is then kept continuously in this range. The CO2 concentration in the warehouse atmosphere is set to approx. 5% by volume. By observing these values for temperature and CC>2 concentration as well as with a; relative humidity on

about. 90%, one can easily achieve: storage times of 10 to 20 months.

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Claims (11)

1. Procedure for the preservation and conservation of perishable products, especially foodstuffs, using liquefied gas as a refrigerant, characterized by the perishable products, possibly, after pre-storage under a controlled atmosphere, are brought into a closable and completely rinsed container', and that in the closed container by controlled blowing in of liquefied gas, a controlled atmosphere is maintained with regard to the temperature and composition of the gas mixture, and if necessary, the products are subjected to a post-cooling while further maintaining the controlled atmosphere. 2. Method according to claim 1, characterized in that the blowing-in process is controlled by means of temperature sensors arranged near the container roof and the container floor, and by means of an apparatus that measures the oxygen and/or gas content. 3. Method according to claim 1 or 2, characterized by keeping the temperature within a range from - 10! to + 20°C. 4. Method according to claims 1 to 3, characterized by using liquefied industrial gas for cooling, as well as carbon dioxide, oxygen or other protective gases for setting the regulated atmosphere. 5. Method according to claims 1 to 4, characterized v! ed that one also sets the air humidity in the container space to/ a pre-determined value. 6. Method according to claims 1 to 5, characterized by bringing fruit or green .case into the container, and sets and maintains the desired temperature and controlled atmosphere in it. 7. Method according to claims 1 to 5, characterized in that meat, fish or fowl are brought into the container, and the desired temperature and controlled atmosphere are set and maintained therein. in i 8. Method according to claims 1 to 5, characterized v; ed that one brings plants, especially flowers, inside the container, and sets and maintains the desired temperature and controlled atmosphere in this. 9. Device for carrying out the method according to claims 1 to 8, characterized in that it perceives a: closable and completely insulated container, which exhibits a battery of bottles with liquefied gas in a separate compartment, and a storage room separated from this for the perishable products, and that there are lines leading from the gas bottles to spray nozzles in the storage room, near the container roof, in which lines! valves are arranged which are controlled by temperature sensors arranged near the container roof and near the container floor, as well as % sensors arranged near the container roof. 10. Sluice for carrying out the method according to one of claims 1 to 8 in connection with a container according to claim 9, characterized by a gas-tight closable entry opening for the container according to claim 9, and which, if necessary: is arranged on a drivable undercarriage, in a storage opening leading to the adjacent storage room and which can also be closed gas-tight, as well as for setting a controlled atmosphere in the lock, necessary gas bottles, fixtures and measuring and regulating devices. 11. Lock according to claim 10, ,. characterized in that it also has a weighing device for checking the loading into the container.