Classifications

• • A—HUMAN NECESSITIES
  • A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
  • A23B—PRESERVING, e.g. BY CANNING, MEAT, FISH, EGGS, FRUIT, VEGETABLES, EDIBLE SEEDS; CHEMICAL RIPENING OF FRUIT OR VEGETABLES; THE PRESERVED, RIPENED, OR CANNED PRODUCTS
  • A23B7/00—Preservation or chemical ripening of fruit or vegetables
  • A23B7/14—Preserving or ripening with chemicals not covered by groups A23B7/08 or A23B7/10
  • A23B7/144—Preserving or ripening with chemicals not covered by groups A23B7/08 or A23B7/10 in the form of gases, e.g. fumigation; Compositions or apparatus therefor
  • A23B7/148—Preserving or ripening with chemicals not covered by groups A23B7/08 or A23B7/10 in the form of gases, e.g. fumigation; Compositions or apparatus therefor in a controlled atmosphere, e.g. partial vacuum, comprising only CO2, N2, O2 or H2O
• • A—HUMAN NECESSITIES
  • A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
  • A23L—FOODS, FOODSTUFFS, OR NON-ALCOHOLIC BEVERAGES, NOT COVERED BY SUBCLASSES A21D OR A23B-A23J; THEIR PREPARATION OR TREATMENT, e.g. COOKING, MODIFICATION OF NUTRITIVE QUALITIES, PHYSICAL TREATMENT; PRESERVATION OF FOODS OR FOODSTUFFS, IN GENERAL
  • A23L3/00—Preservation of foods or foodstuffs, in general, e.g. pasteurising, sterilising, specially adapted for foods or foodstuffs
  • A23L3/34—Preservation of foods or foodstuffs, in general, e.g. pasteurising, sterilising, specially adapted for foods or foodstuffs by treatment with chemicals
  • A23L3/3409—Preservation of foods or foodstuffs, in general, e.g. pasteurising, sterilising, specially adapted for foods or foodstuffs by treatment with chemicals in the form of gases, e.g. fumigation; Compositions or apparatus therefor
  • A23L3/3418—Preservation of foods or foodstuffs, in general, e.g. pasteurising, sterilising, specially adapted for foods or foodstuffs by treatment with chemicals in the form of gases, e.g. fumigation; Compositions or apparatus therefor in a controlled atmosphere, e.g. partial vacuum, comprising only CO2, N2, O2 or H2O

Definitions

• the invention relates to a system for controlling the atmosphere in at least one gas-filled space which has a gas supply conduit and a gas discharge conduit, comprising at least one adsorption device for connecting alternately to the space or the environment which comprises at least one container filled with adsorption material .
• Such a device is generally known under the name “scrubber” and is used for instance in cold stores or other spaces in which living products such as agricultural or horticultural products are stored.
• the storage life of these products depends not only on the storage temperature but also on the concentrations of constituents such as C0 2 , 0 2 and ethylene of the gas mixture in the cold store.
• the gas mixture from the refrigeration cell is guided through the active carbon, wherein C0 2 and/or ethylene is adsorbed to the active carbon and the gas mixture poor in C0 2 and/or ethylene is fed back to the space .
• the adsorption material must be regenerated, which takes place by guiding outside air through the adsorption material, wherein C0 2 and/or ethylene desorbs and the outside air mixture enriched with C0 2 and/or ethylene is returned to the outside air.
• the time period required for regeneration depends on the component adsorbed to the active carbon.
• the regeneration period is generally adapted to the time required for desorption of the C0 2 gas. An optimum desorption of ethylene requires on average two to three times as much time.
• the active carbon is "flushed", after the regeneration process has terminated, with a quantity of low-oxygen gas mixture, which is discharged to the environment after flushing.
• a small quantity of ambient air is guided through the active carbon, the 0 2 of which is adsorbed to the active carbon, so that a low-oxygen gas mixture is obtained which is fed to the cell .
• This quantity of mixture is practically as large as the quantity used for flushing the active carbon.
• a drawback of all the known systems described above is that they are only suitable for controlling the atmosphere in a particular number of cells and do not lend themselves well to enlarging of the scrubbing capacity.
• the known systems are not very suitable for application in situations in which different products with varying storage requirements are stored in the refrigeration cells connected thereto, such as for instance apples in one cell and pears in another cell.
• the invention therefore has for its object to provide a system of the above described type wherein these drawbacks do not occur.
• This is achieved according to the invention in that the or each container is provided on either side with at least one connecting tube for connecting to the gas supply conduit respectively the gas discharge conduit, which connecting tube is adapted to transport a larger quantity of gas than will flow through the container per unit of time.
• each connecting tube can have means for connecting the gas supply conduit respectively the gas discharge conduit to a plurality of adsorption containers and have for instance at least three connecting openings.
• the connecting tubes are preferably connected to the gas supply conduit respectively the gas discharge conduit with interposing of at least one controllable valve, which is adapted to allow passage of a larger quantity of gas than will flow through the container per unit of time.
• the system can be enlarged in simple manner without the valves having to be replaced for this purpose.
• the containers filled with adsorption material are preferably accommodated in an extensible frame, so that by extending the frame space is created in simple manner for the addition of extra containers filled with adsorption material . In this manner a system can be simply formed wherein the adsorption device comprises a plurality of containers which are mutually connected in parallel and filled with adsorption material and which thus have a large capacity.
• the containers of the adsorption device can herein be connected to at least one of their connecting tubes with interposing of at least one controllable valve, so that a part of the containers can be closed off for differing treatment of gas from different cells and to prevent transfer of particular components such as for instance ethylene between the cells.
• valves When there are at least two adsorption devices connected in parallel, the connecting tubes of which are connected to the gas supply conduit respectively the gas discharge conduit with interposing of a plurality of valves, of which at least a part are controlled in pairwise manner, pressure differences in the treated cells can be prevented in that each time an adsorption device is flushed with gas from the cell a corresponding quantity of gas is simultaneously guided back to the cell via the other adsorption device.
• control of the valves is herein very simple.
• Several of the pairwise controlled valves can advantageously be combined to form three-way valves.
• valves In order to limit the costs of such valves, since according to the invention they are overdimensioned, these valves preferably have a tubular valve housing manufactured from plastic. In addition, the valves can advantageously be pneumatically controllable.
• the invention further relates to a valve which is intended for use in the system as described above.
• the invention relates to a method for controlling the atmosphere in a gas-filled space making use of the system with a plurality of containers connected in parallel as described above, comprising of extracting from the space a part of the gas present therein, guiding the gas extracted from the space through the adsorption device and subsequently guiding the gas back to the space, wherein the adsorption device is periodically regenerated by guiding ambient air therethrough, wherein according to the invention the gas extracted from the space and the ambient air are then guided in each case through at least one of the containers connected in parallel and filled with adsorption material .
• the adsorption capacity can be adapted simply to the requirement, while there is moreover the possibility of separate treatment of the gas from the different cells.
• gas from different cells can be treated in different ways, while the adsorption material in all containers can be regenerated optimally. Furthermore, the transfer of for instance ethylene between the cells is thus prevented.
• the atmosphere in at least one of the spaces herein has a composition different from that in the other spaces, the gas from this one space is guided through at least one first container of the adsorption device, wherein at least one second container is closed and the gas from the other spaces is guided through at least one second container, wherein the or each first container is closed.
• fig. 1 is a schematic view of a system wherein the invention can be applied
• fig. 2A to 2D show schematically the different steps of an adsorption and regeneration cycle
• fig. 3 is a schematic view of the adsorption devices and valves connected thereto for the system of fig. 1 when the invention is applied
• fig. 4 is a view corresponding with fig. 3 of an alternative embodiment of the system with a plurality of containers connected in parallel for each adsorption device
• fig. 5 is a schematic view of yet another embodiment of the system with a plurality of containers connected in parallel which can be closed as required
• fig. 1 is a schematic view of a system wherein the invention can be applied
• fig. 2A to 2D show schematically the different steps of an adsorption and regeneration cycle
• fig. 3 is a schematic view of the adsorption devices and valves connected thereto for the system of fig. 1 when the invention is applied
• fig. 4 is a view corresponding with
• FIGS. 6A to 6D and 6E to 6H are schematic views corresponding with fig. 2A to 2D of the different steps of the adsorption and regeneration cycle according to the invention
• fig. 7 is a partly sectional side view of a valve for use in the system of fig. 3, 4 and 5.
• a system for controlling the atmosphere in a number of gas-filled spaces or refrigeration cells 13, 14, 15, a so-called cross-scrubber comprises two adsorption devices 20, 21 which are connected in parallel and each formed by a container 28, 29 filled with active carbon and a pump 22, 23 (fig. 1) .
• Each of the spaces 13, 14, 15 has a gas discharge conduit 16 and a gas supply conduit 17.
• the separate supply and discharge conduits are connected to collecting conduits 18 and 19, which guide gas via connecting conduits 24 and 25 respectively to and from adsorption devices 20, 21.
• the adsorption devices can also be connected to the environment via openings 26 and 27.
• Controllable valves 1-12 are arranged between the adsorption devices, the refrigeration cells and the environment. By operating these valves as indicated in the table below is successively brought about that:
• valve pairs 1 and 4, 2 and 3 and 5 and 6 could also be operated together.
• a number of the above stated valve pairs are combined to form three-way valves. This relates to valve pairs 1 and 4, 2 and 6, 8 and 12, 7 and 10, 3 and 5 and 9 and 11, which are replaced by the three-way valves 35, 36, 37, 38, 39 and 40 (fig. 3) . By making use of such three-way valves the number of valves can be limited considerably.
• These three-way valves 35-40 can likewise be operated pairwise.
• valves 35 and 38 are each connected via pneumatic lines 52 and 53 to an electropneumatic switch unit 54 operated by a process control program, while LO LO t t .
• Pneumatic cylinder 47 is mounted on a base 50 of a cap 51 which is pushed into one outer end 58 of tubular body 41.
• the opposite end 57 of tubular body 41 functions as third connecting stub of three-way valve 35.
• the connecting stub 42 is hermetically sealed, while transport of gas is possible between connections 43 and 57.
• valve 44 is moved to the position 44' shown with dashed lines by extending piston rod 59 of pneumatic cylinder 47, the connection 57 is then hermetically sealed and transport of gas is possible between connections 42 and 43.
• Such a three-way valve is suitable for allowing through-flow of relatively large quantities of gas while the manufacturing costs thereof are relatively low, so that the cost of the system as a whole will be relatively low.
• the system can, as stated, be enlarged in simple manner by adding extra adsorption containers 28', 28", 29', 29" (fig. 4).
• the conduits and valves can herein be retained.
• the control unit for the system (not shown) can also remain basically unchanged. At the very most a control program will have to be adapted somewhat, but even this will not always be necessary.
• Adsorption containers 28 ) 28', 28", 29, 29', 29", fans or pumps 22 or 23 and all conduits can herein be accommodated in a frame or housing, which is not shown here but which can take an extensible form in order to enable the enlarging with a plurality of adsorption containers 28', 28", 29', 29".
• the frame or housing can also be embodied for easy extension, whereby frame modules with extra adsorption containers 28', 28", 29', 29" can readily be connected to the existing frame.
• containers 68, 69 with a different adsorption material can otherwise also be added to the system (fig. 5) .
• Gas from different spaces can hereby be treated in different ways. This is important for instance when in one of the spaces a different, more vulnerable type of product is stored than in the other spaces.
• Containers 28, 28', 29 and 29' could function for instance as C0 2 scrubber, while containers 68 and 69 could operate as C0 2 and ethylene scrubber. These containers 68, 69 could then for instance be used exclusively for treating gas originating from a space in which products are stored which are sensitive to ethylene, such as pears, Elstar apples, kiwi fruit and the like, while the other containers 28, 28', 29 and 29' could be used collectively for treating gas originating from the other cells, which may for instance contain other apple varieties such as Jonagold or Cox. Thus is prevented that the ethylene content in the cell filled with ethylenesensitive products increases inadvertently as a result of co-displacement of ethylene left behind in containers 28, 29.
• CD tr ro ro ro Hi F 1 P ) ro ro ro i ro Pi ⁇ Pi n P F- cn ⁇ 3 O rt O ⁇ P — rt rt o rt tr ro rt rt 3 tr CD rt •• CD o tr
• the invention thus provides the option of treating, in simple and precisely controlled manner, widely varying quantities of gas originating from spaces in which are stored products which may differ considerably, while making use of very simple and therefore inexpensive installations .

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• Chemical & Material Sciences (AREA)
• Life Sciences & Earth Sciences (AREA)
• Engineering & Computer Science (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Food Science & Technology (AREA)
• Polymers & Plastics (AREA)
• Health & Medical Sciences (AREA)
• Nutrition Science (AREA)
• Wood Science & Technology (AREA)
• Zoology (AREA)
• Separation Of Gases By Adsorption (AREA)

Priority Applications (1)

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Publications (1)

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Family Applications (1)

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Cited By (3)

Citations (6)

• 1997
  • 1997-01-16 NL NL1005014A patent/NL1005014C2/nl not_active IP Right Cessation
• 1998
  • 1998-01-16 AU AU55781/98A patent/AU5578198A/en not_active Abandoned
  • 1998-01-16 WO PCT/NL1998/000027 patent/WO1998031235A1/en active Application Filing

Patent Citations (6)

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