WO2012149611A1 - Apparatus and methods for controlling atmospheric gas composition within a container - Google Patents
Apparatus and methods for controlling atmospheric gas composition within a container Download PDFInfo
- Publication number
- WO2012149611A1 WO2012149611A1 PCT/AU2012/000486 AU2012000486W WO2012149611A1 WO 2012149611 A1 WO2012149611 A1 WO 2012149611A1 AU 2012000486 W AU2012000486 W AU 2012000486W WO 2012149611 A1 WO2012149611 A1 WO 2012149611A1
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- WIPO (PCT)
- Prior art keywords
- container
- gas
- accordance
- membrane
- controller
- Prior art date
Links
- 238000000034 method Methods 0.000 title claims abstract description 58
- 239000000203 mixture Substances 0.000 title claims abstract description 24
- 239000007789 gas Substances 0.000 claims abstract description 147
- 239000012528 membrane Substances 0.000 claims abstract description 114
- 239000012080 ambient air Substances 0.000 claims abstract description 14
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 claims description 70
- 229910002092 carbon dioxide Inorganic materials 0.000 claims description 53
- 239000001301 oxygen Substances 0.000 claims description 50
- 229910052760 oxygen Inorganic materials 0.000 claims description 50
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 49
- 239000001569 carbon dioxide Substances 0.000 claims description 35
- 238000012360 testing method Methods 0.000 claims description 35
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 20
- 238000012544 monitoring process Methods 0.000 claims description 20
- 230000015654 memory Effects 0.000 claims description 13
- 238000004422 calculation algorithm Methods 0.000 claims description 12
- 238000004891 communication Methods 0.000 claims description 12
- 229910052757 nitrogen Inorganic materials 0.000 claims description 10
- 238000003860 storage Methods 0.000 claims description 10
- 239000012530 fluid Substances 0.000 claims description 8
- 230000004044 response Effects 0.000 claims description 6
- 239000012466 permeate Substances 0.000 claims description 5
- 238000004590 computer program Methods 0.000 claims description 3
- 238000005057 refrigeration Methods 0.000 claims description 2
- 239000003570 air Substances 0.000 description 17
- 230000035699 permeability Effects 0.000 description 12
- 230000029058 respiratory gaseous exchange Effects 0.000 description 8
- 238000000605 extraction Methods 0.000 description 7
- 238000005259 measurement Methods 0.000 description 5
- 230000006870 function Effects 0.000 description 4
- 230000002093 peripheral effect Effects 0.000 description 4
- 241000234295 Musa Species 0.000 description 3
- 238000004458 analytical method Methods 0.000 description 3
- 230000008901 benefit Effects 0.000 description 3
- 230000008859 change Effects 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 2
- 239000011358 absorbing material Substances 0.000 description 2
- 235000021015 bananas Nutrition 0.000 description 2
- 238000004364 calculation method Methods 0.000 description 2
- 229910052799 carbon Inorganic materials 0.000 description 2
- 238000004320 controlled atmosphere Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 230000006872 improvement Effects 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012545 processing Methods 0.000 description 2
- 230000009467 reduction Effects 0.000 description 2
- 239000012465 retentate Substances 0.000 description 2
- 239000011800 void material Substances 0.000 description 2
- 235000018290 Musa x paradisiaca Nutrition 0.000 description 1
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 1
- DHXVGJBLRPWPCS-UHFFFAOYSA-N Tetrahydropyran Chemical compound C1CCOCC1 DHXVGJBLRPWPCS-UHFFFAOYSA-N 0.000 description 1
- 238000007792 addition Methods 0.000 description 1
- 230000004075 alteration Effects 0.000 description 1
- 238000013459 approach Methods 0.000 description 1
- 229920002301 cellulose acetate Polymers 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 235000013399 edible fruits Nutrition 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 238000011010 flushing procedure Methods 0.000 description 1
- 235000012055 fruits and vegetables Nutrition 0.000 description 1
- 238000004868 gas analysis Methods 0.000 description 1
- 238000003306 harvesting Methods 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 238000013178 mathematical model Methods 0.000 description 1
- 239000003921 oil Substances 0.000 description 1
- 150000002926 oxygen Chemical class 0.000 description 1
- 239000011148 porous material Substances 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 238000005086 pumping Methods 0.000 description 1
- 238000010926 purge Methods 0.000 description 1
- 230000005070 ripening Effects 0.000 description 1
- 238000005201 scrubbing Methods 0.000 description 1
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Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
- B65D—CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
- B65D81/00—Containers, packaging elements, or packages, for contents presenting particular transport or storage problems, or adapted to be used for non-packaging purposes after removal of contents
- B65D81/18—Containers, packaging elements, or packages, for contents presenting particular transport or storage problems, or adapted to be used for non-packaging purposes after removal of contents providing specific environment for contents, e.g. temperature above or below ambient
- B65D81/20—Containers, packaging elements, or packages, for contents presenting particular transport or storage problems, or adapted to be used for non-packaging purposes after removal of contents providing specific environment for contents, e.g. temperature above or below ambient under vacuum or superatmospheric pressure, or in a special atmosphere, e.g. of inert gas
- B65D81/2069—Containers, packaging elements, or packages, for contents presenting particular transport or storage problems, or adapted to be used for non-packaging purposes after removal of contents providing specific environment for contents, e.g. temperature above or below ambient under vacuum or superatmospheric pressure, or in a special atmosphere, e.g. of inert gas in a special atmosphere
- B65D81/2076—Containers, packaging elements, or packages, for contents presenting particular transport or storage problems, or adapted to be used for non-packaging purposes after removal of contents providing specific environment for contents, e.g. temperature above or below ambient under vacuum or superatmospheric pressure, or in a special atmosphere, e.g. of inert gas in a special atmosphere in an at least partially rigid container
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/22—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by diffusion
-
- 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
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D63/00—Apparatus in general for separation processes using semi-permeable membranes
- B01D63/02—Hollow fibre modules
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2256/00—Main component in the product gas stream after treatment
- B01D2256/22—Carbon dioxide
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2257/00—Components to be removed
- B01D2257/10—Single element gases other than halogens
- B01D2257/104—Oxygen
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/30—Controlling by gas-analysis apparatus
Definitions
- the invention relates generally to a method of and apparatus for controlling atmospheric gas composition within a container, and in particular for extending the life of perishable goods, for example during transport.
- the conventional method of extending storage life of produce has been to refrigerate the container and to reduce carbon dioxide levels (as carbon dioxide is generated by respiring produce), while maintaining oxygen and nitrogen at desired levels.
- the present invention seeks to ameliorate one or more of the abovementioned disadvantages, or at least provide a new method of controlling the atmosphere in a container, and/or new container apparatus, and/or apparatus for controlling the atmosphere in the container. Summary of the invention
- a method of controlling gas composition within a container containing respiring produce including at least one gas outlet and at least one gas inlet, the method including the steps of. drawing gas from within the container through a selective membrane element under selected control conditions through the at least one gas outlet;
- the selected control conditions under which drawing is conducted are that mere is a drawing step when a pump is actuated t draw gas through the membrane element from within the container at a selected range of flowrates and a holding step where the flowrate through the membrane is minimised.
- the drawing step and the holding step are alternated so that there is generally intermittent drawing of gas.
- control conditions arc that the drawing step is of one duration and the holding step is of another duration and the two durations are of unequal size.
- the drawing step is shorter than the holding step to facilitate an equilibrium of gas components and pressures -within the container.
- the drawing step is up to about 20 times shorter in duration man the holding step.
- the drawing step includes selectively drawing carbon dioxide through the membrane element, so that it is extracted from the container at a higher rate than other gases present within the container.
- the method includes the step of conducting a container gas tightness test and including the level of leakage, if any, in a control algorithm.
- the method includes the step of monitoring levels of one or more gas components of die gas mixture inside the container to provide one or more gas component level readings
- the introducing step may be in response to the one or more gas component readings.
- the monitoring step includes monitoring of oxygen
- the selected control conditions under which drawing is conducted include changing a rate of drawing of gas from within the container over time.
- the selected control conditions under which introducing ambient air is conducted include changing a rate of introduction of ambient air from outside the container over time.
- the gas drawn from the container is carbon dioxide.
- the rate of drawing of gas from within the container varies between a maximum rate and a zero rate of drawing, representing respectively a drawing step and a holding step.
- the selected drawing control conditions are intermittent on-off between the maximum rate of drawing and holding.
- the control conditions may include a situation where the drawing step and the holding step axe of approximately equal t me durations. In one embodiment, this time duration may be approximately 15 minutes.
- Other suitable time durations are include approximately 1 minute, 2 mins, 5 mins, 10 mins, 20 mins, 30 mine, 45 mins, and 1 hour, 2 hours, as well as unequal on-off times, such as 10 mins on, 20 mins off, 20 mins on 10 mins off, and so on.
- Some kinds of fruit payioads may suit a drawing step of 15 minutes and a holding Btep of 300 minutes, whereas some others may require, for stability, a drawing step of 60 minutes and a holding step of 30 minutes.
- Other combinations are contemplated and vary according to the respiration rate of and temperature required for the extended life of the particular payioad of produce.
- control conditions may include a rate of change of drawing of the gas, or rate of change of introduction of oxygen from a bottle or ambient air may be governed by a sinusoidal pattern, or a sawtooth pattern, or other suitable waveform.
- the gradient of the sawtooth may be steep between drawing and holding, and flatter between a subsequent holding and drawing, so that there is a longer gap for allowing restoration of equilibrium conditions, or the waveform may be more of a uniform.
- the drawing step may be merely reduced in amplitude so that the drawing is brought to a trickle, rather than reducing drawing to a complete holding stop. This trickling may have other advantages, such as for example reducing unintentional reverse movements of other gases through the membrane.
- the gas-monitoring step may include the step of monitoring the level of oxygen ithin the container.
- the step of measuring the level of oxygen is combined with comparing that level with a desired set point and then introducing the ambient air to the container in accordance with the selected control conditions.
- the selected control conditions Preferably the
- measurement of the gas is routinely conducted, at selected spaced-apart time intervals, and the amount of introduced gas for that time interval is dependent on the difference between the measured gas level and the selected set point.
- the gas-monitoring step may also include the monitoring of carbon dioxide (CO]) gas within the container.
- the method may also include the step of comparing the measured amount of CO z gas in die container and then altering the control conditions of selective extraction of CO a .
- the selected control conditions may be a reduced or zero flow rate at selected times, caused by a throuling step.
- the throttling step may be caused by a diaphragm being placed across the feed and/or sweep side of the membrane unit, or by some other physical or mechanical interference to increase the pressure and reduce the flowrate through the membrane unit
- the throttling may be by a venturi, orifice, partial blockage, choke, variable aperture, sphincter or some porous material such as a sintered block, sponge, or other suitable substance.
- the throttle may throtde by being extended into the feed or sweep streams by a transducer.
- This preferred form of the invention includes controlled modulation of duty flow, through an intermittent operation of the membrane element.
- a reduced or zero COj extraction flow allows time for the oxygen level within the container to build up, avoiding the risk that continuous drawing of C0 2 through the membrane (which will include significant levels of gases other than COj) will lead to instability, as the air inlet introduction operates in response to the monitoring of oxygen level.
- the drawing step may be considered a forced permeation of gas through the membrane element.
- carbon dioxide is drawn through the membrane element at a higher rate than other gases present within the container, in particular, oxygen and nitrogen.
- the membrane element preferably has a selectivity which allows carbon dioidde gas to permeate through the membrane element at a higher rate than oxygen and nitrogen, preferably at a ratio of between about 2.5 and about IS.
- Preferred selectivity ranges for COj Nz are between about 5 and 50.
- the selectivity of a suitable membrane for carbon dioxide over oxygen (COj/Oa) is relatively modest or low at between about 4 and 5 and the selectivity for a suitable membrane for carbon dioxide over nitrogen (CO J /N J ) is similarly modest, at between about 7 and 14.
- This particular membrane is manufactured from Pofydimethyisiloxane (PDMS).
- the invention is implemented without any other means of drawing or extracting carbon dioxide gas.
- Membranes contemplated include an overall permeability for C0 2 of about 3000 Barrer and comprise a thickness of about 35um, This is a very high permeability and other materials are contemplated to be useful, including cellulose acetate, which has an overall permeability for C0 2 of 6.3 Barrer. This is a large difference, but it can be mitigated by altering the thickness of the membrane and having a large membrane area.
- Preferred membranes have been shown to be about 3100 Barrers of permeability for C0 2 and 35 ⁇ in thickness. Therefore the permeability per unit thickness for a suitable membrane is about 88 Barrers/AUn.
- One type of suitable membrane for use with preferred embodiments of the present invention is inaniiiactured from
- PDMS PolydimethylsilaxHne
- preferred embodiments of the method of the present invention utilise a membrane of moderate C0 2 selectivity, but a membrane which is widely available in the size and format, at a reasonably low cost.
- the advantage of the preferred embodiments of the present invention are that a membrane with a low selectivity and low cost can be utilised in a control system to provide a stable, controlled, suitable atmosphere for extending the life of respiring goods in transit,
- a container suitable for storing respiring produce including:
- At least one gas outlet and a selective membrane unit in fluid communication with the gas outlet so that in use gas within the container may be drawn therethrough, from the container to outside the container;
- a pump in fluid communication with the membrane unit for drawing gas through the membrane unit
- At least one gas inlet for introducing atmospheric gas from outside the container to the void, and a valve fe controlling gas flow through the gas inlet; one or more controllers for selectively controlling operation of the pump and valve.
- a sensor for sensing levels of one or more gases within the container Preferably the sensor is an oxygen sensor.
- another sensor is a carbon dioxide sensor.
- a second gas outlet for evacuating container gas therethrough.
- a valve is provided on the second outlet to control the evacuation of container atmospheric gas therethrough.
- the container includes a refrigeratioti unit.
- a throtde or choke to increase the pressure and reduce the flow of gases through the feed and sweep portions of the membrane unit.
- the one or more controllers include a processor, a memory, an input/output device, such that the or each controller is responsive to a program to control the operation of valves and pumps in response to various inputs,
- the or each controller also includes a timer for measuring time elapsed in storage for the respiring produce so as to operate a control algorithm which operates the membrane unit based on time elapsed.
- the or each controller is adapted to receive inputs from such devices as the timer, thermocouples, gas monitors, inputs from operators via the input/output device, including mass and type of produce,
- the memory and processor may be loaded with tables for calculating run times for various payloads and produce types.
- the setpoint for the C0 3 may be about 5%.
- the container will not be wholly sealed from the outside atmosphere. That is, there will be some leakage into the container or from the container, depending on die pressure differential between inside and outside the container.
- analysis of gas-tightness may be used to calibrate the system, to ensure leakage will not unduly affect operation of the invention.
- the base leakage of the container is less than the respiration rate of the produce in the container.
- the method and apparatus of the present invention can utilise, among other steps, the step of monitoring of oxygen and controlled input of atmospheric air to the container from outside, which affects the control and levels of carbon dioxide inside the container.
- a computer that is arranged for operation in accordance with a method of controlling atmospheric gas composition within container suitable for storing respiring produce, the container including at least one gas outlet and at least one gas inlet, the method including the steps of: drawing gas from within the container through a membrane element through the at least one gas outlet under selected control conditions; and introducing atmospheric gases from outside the container into the container through the at least one gas inlet under selected control conditions to control the relative composition of gases inside the container.
- a computer program for instructing a computer and arranged so that, when loaded in the computer, the computer operates as a controller for controlling atmospheric gas composition within a container in accordance with methods herein described.
- a computer readable program code embodied therein for causing a computer medium to operate as a controller for controlling atmospheric gas composition ithin a container in accordance with methods hereindescribed.
- a data signal having a computer readable program code embodied therein for causing a computer to operate as a controller for controlling atmospheric gas composition within a container in accordance with methods hereindescribed.
- Figure 1 is a schematic drawing of a container according to one embodiment of the present invention.
- Figure 2 is a schematic view of a testing arrangement of a scaled-down container generally in accordance with an embodiment of the present invention which has been constructed to show results set out herein;
- Figure 3 is an end elevation -view of a membrane unit used in the testing arrangement of Figure 2;
- Figure 4 is a side elevation view of the membrane unit of Figure 3 ;
- Figure 5 is a cutaway isometric view of the membrane unit of Figure 3;
- Figure 6 is a graph of results which were produced in the testing arrangement of Figure 2 under selected initial conditions
- Figure 7 is a graph of results which were produced in the testing arrangement of Figure 2 under other selected initial conditions.
- Figure 8 is a graph of results which were produced in the testing arrangement of Figure 2 under further selected initial conditions.
- Figure 9 is a graph of results which were produced in the testing arrangement of Figure 2 under still further selected initial conditions.
- Figure 10 is a graph of results which were produced in the testing arrangement of Figure 2;
- Figure 11 is a schematic drawing of a container according to another embodiment of the present invention.
- Figure 12 is a schematic view of a processing system which is part of a controller for use with a preferred embodiment of the present invention
- Figure 13 is a schematic view of a portion of the architecture of the processing system of Figure 12;
- Figure 14 is a schematic view of a distributed architecture which may be used as a controller
- Figure 15 is a graph of results of a test of an Improved model of a preferred embodiment of the present invention which shows that there was an intermittency of 15 minutes pumping out of a 300 minute cycle and that stability of gas composition was obtained at suitable levels;
- Figure 16 is a graph of results of another test of the improved setup, with a different intermittency signature of 1575minutes, wherein atmospheric air was the starting conditions for the air composition inside the container;
- Figure 17 is another graph of further test results in the improved test setup, with an intermittency of 15/30 minutes, as previously tested.
- FIG. 1 there is shown a refrigerated container 10 which includes a refrigeration unit 12 and doors 14.
- the container 10 in use contains respiring produce 13, and further includes gas outlets 20 and 22 and gas inlet 24.
- the container 10 also includes a membrane unit JO which is in Quid
- a pump is associated with the membrane unit 30 which draws gas from the container 10 through a membrane (not shown) of a predetermined selectivity so that some gases from the container are drawn through (ie. permeate through) the membrane at a greater rate than other gases,
- the selectivity of die membrane of the embodiment shown is relatively modest or low, at about 4 or 5:1 for C0 2 :0 2 and about 10 or 11:1 for CO a :Nj.
- Other selecdvities for the membrane may be used, including between about 2.5 and 15.
- a useful membrane used in tests has been shown to have an absolute permeability for C0 2 of about 3100 Barrer and comprises a thickness of about 35/xm. Therefore the permeability per unit thickness for a suitable membrane is about 88 Barrer per ⁇ .
- One material useful for the purposes of the test set out herein is PotydJmetrry oxane (PDMS).
- PDMS PotydJmetrry oxane
- the container further includes a controller 8 which includes a CPU, a memory, a processor, actuators for actuating the pump on the membrane unit 30, actuators for valves 20, 22 and 24, as well as a sensor in the form of an oxygen concentration measurement device.
- the controller may also receive inputs relating to temperature in the container, pressure in the container, other gas sensors, and the like.
- One function of the controller 8 is to actuate the pump on the membrane unit 30 in accordance with a selected control regime.
- An effective control regime is to vary the drawing of gas from within the container over time.
- This control regime which testing has demonstrated can be used in maintaining an 0 2 setpoint of about 5% and a C0 2 setpoint of about 7% in a scaled-down container of 750L, is to draw the gas out of container 10 in an intermittent manner. This means that control varies from a maximum drawing rate fo a first prescribed time period, to a zero drawing rate for a second prescribed time period.
- the maximum drawing rate of C0 2 in the test was about 0,25 SLPM (an overall air-drawing rate through the membrane unit was about 30 Standard Litres Per Minute (SLPM)) and the on-off times (the first and second prescribed time periods) were both 15 minutes.
- SLPM Standard Litres Per Minute
- control may vary between said maximum drawing rate for a first prescribed time period and a lower drawing race for a second prescribed time period- It will also be appreciated that control regimes other than a step function may be used, such as sinusoidal, sawtooth or other waveform between drawing rates.
- control regimes other than a step function may be used, such as sinusoidal, sawtooth or other waveform between drawing rates.
- the important common feature is the intermittency of operation of membrane unit 30, so allowing successive periods of time for an equilibrium to be re-established.
- controller 8 makes measurements of xygen concentration at selected intervals. If the oxygen concentration varies from a selected value (a 'setpoint*, which may be preset in accordance with the rate of respiration of produce 13 in the container), controller 8 sends a signal via wires 17 or other communication means to open valves 20 and 24. This introduces air from outside the container 10 through inlet 24 and draws air from container 10 through outlet 20. Oudet 20 may include a fan to force air from the container. A fan may also be provided on inlet 24 to draw air into the container 10.
- a 'setpoint* which may be preset in accordance with the rate of respiration of produce 13 in the container
- the portion of the controller 8 which is responsible for oxygen concentration operates on an 8- minute cycle. That is, every 8 minutes the sensor checks the oxygen concentration level, and compares it with the set point. If the level is within an acceptable range of deviation from the same as die set point, the valves 20 and 24 are not opened. If there is a large difference between the desired set point and die measured level, the valves are opeaed for most of the 8-minute interval. If there is a small difference, the valves are opened for small portion of the 8-minute interval.
- the system of one embodiment of the present invention might also operate without the sensor means far measuring oxygen.
- selected calculations are made, and selected inputs provided to the controller so that the controller can function to maintain selected gas concentrations, in particular, C0 3 and 0 2 at selected levels.
- These calculations and inputs include at least respiration rate of produce, volume/mass of produce, temperature of atmosphere inside container, gas leakage rate of container 10 (through doors, seals etc) and gas transfer rates through valves 20, 22, 24 and membrane unit 30.
- the controller can calculate the control regime required, for example, the nature of intermittent operation required (first and second prescribed time periods).
- Figure 11 shows a schematic layout of another arrangement of the present invention described above where there is no sensor.
- the controller includes a timer to operate the valves.
- Figure 12 shows a block diagram of operative components of a controller 1100 which may be the same as the controller 8 shown in Figure 1.
- the method of preferred einbodiments of the present invention may be executed by such a machine, smartphone or other computer, generally as hereinafter described,
- the controller 1100 includes a control device 1101 having a processor 1102. Instructions and data to control operation of the processor 1 02 in accordance with preferred embodiments of the present invention are stored in a memory 1103 which is in data communication with die processor 102.
- the controller 1100 will include both volatile and non-volatile memory and more than one of each type of memory, with such memories being collectively represented by the memory 1103-
- FIG. 13 shows a block diagram of the main components of an exemplary memory 1103.
- the memory 1103 includes RAM 1103A, EPROM 1103B and a mass storage device 1103C.
- the RAM 1103A typicalr temporarily holds program files for execution by the processor 1102 and related data.
- the EPROM 1103B may be a boot ROM device and/or may contain same system or control-related code.
- the mass storage device 1103C is typically used to store control programs, the integrity of which may be verified and/or authenticated by the processor 1102 using protected code from the EPROM 1103B or elsewhere.
- the controller 1100 has an input/output (I O) interface 1105 for communicating with an operator interface 1120 of the controller 1100, the operator interface 1120 hawing several peripheral devices.
- the input/output interface 1105 and/or the peripheral devices may be intelligent devices with their own memory for storing associated instructions and data for use with the input output interface or the peripheral devices.
- the peripheral devices that communicate with the control device 1101 comprise one or more displays 1106, a touch screen 1107 and a printer 1109. Additional hardware may be included as part of the controller 1100, or hardware may be omitted as required for the specific implementation.
- the controller 1100 may include a communications interface, for example a network card 1112.
- the network card may, for example, send status information or other information to a central controller, server or database and receive data or commands from the central controller, server or database.
- controller 1100 It is also possible for the operative components of the controller 1100 to be distributed, for example input output devices 1106, 107, 1108, 1109, 110, 1111 may be provided remotely from the atmosphere controller 1101.
- FIG. 14 shows a control system 200 in accordance with an alternative embodiment.
- the control system 200 includes a network 201, which for example may be an Ethernet network, a LAN or a WAN.
- a network 201 which for example may be an Ethernet network, a LAN or a WAN.
- three banks 203 of two control machines 202 are connected to the network 201.
- the control systems 202 provide a control interface and may be the same as the controller 8 shown in Figure 1, or may have simplified functionality depending on the requirements for implementing control, such as controlling a bank of containers at once. 'although banks 203 of two controllers are illustrated in Figure 14, banks of one, three or more controllers are also envisaged.
- One or more displays 204 may also be connected to the network 201.
- the displays 204 may, for example, be associated with one or more banks 203 of controllers.
- the displays 204 may be used to display representations associated with control situations on the control machines 202, and/or used to display other representations .
- a control server 205 implements part of the control system using a control system 202 and the control system 202 implements part of die control algorithm. With this embodiment, as both the control server 205 and the control system 202 implement part of the control, they collectively provide a controlled atmosphere controller.
- a database management server 206 may manage storage of algorithms and associated data tor downloading or access by the control devices 202 In a database 206A.
- control machine 202 may implement the control, with the control server 203 functioning merely to serve data indicative of a control algorithm or method to a control machine 202 for implementation.
- a data signal containing a computer program usable by the client terminal to implement the control method may be transferred from the control server to the client terminal, for example in response to a request by the client terminal.
- control server 205 implements most or all of the method by an operator using a, control machine 202 and die control machine 202 essentially provides only the operator interlace.
- the control server 205 provides the method controller, The control machine will receive instructions, and pass the instructions to the control server which will process them and return settings and other outcomes to the control machine and display them.
- the control machines could be computer terminals, e.g. PCs running software that provides a user interface operable using standard computer input and output components.
- the control system 200 may communicate with other control systems, other local networks such as a corporate network, and or a wide area network such as the Internet, for example through a firewall 211.
- test set up has been constructed to demonstrate the effectiveness of a preferred embodiment of the invention, in accordance with Figure 2. It will be understood by persons skilled in the art that the test set up includes features which would not be required for the invention to function in a. commercial embodiment, since certain measurements and functionalities useful for tests are not required in the commercial embodiment.
- the test Included a container 110 of 750L volume, and a 153.1kg load of bananas 113 disposed in the container 110.
- the containe 110 was refrigerated at about 11°C.
- the container 110 was disposed in a test laboratory set at about 22°C.
- a controller was provided at 108.
- the controller 108 was operatively connected to vidves 120 and 122 and 124 in the walls of the container, and to a membrane unit 130- Fans 121 and 123 are also provided to force air from the container and to draw air into the container firom outside the container through the valves 120 and 124.
- the membrane unit 130 was a PDMS membrane unit, which has a moderate selectivity to C0 2 , ie, preferentially selecting C0 2 over 0 2 and N 2 when drawing gases from the container 110.
- the membrane unit 130 is shown in Figures 3-5, in which a generally cylindrical module housing 198 houses a plurality of hollow membrane (POMS) fibres 197.
- the housing 198 includes side or feed ports 196 which are in fluid communication -with an inside of the hollow PDMS membrane fibres.
- side port 194 functioned as an inlet port
- side port 193 functioned as an outlet or retentate pott in fluid
- the housing 198 further includes shell side ports or outlet ports 191, 189 and 188 which are in fluid communication with the outside of the hollow PDMS membrane fibres 197. That is, these ports include permeate which is extracted from the container and is directed to ambient air outside the container 110.
- container atmospheric gas is pumped from outlet 122 into side port 194. A portion of that gas permeated through the membrane 197 and into the outlet ports 191, 189 and 188 and a portio returned to the container 110 via side port 193 and valve 146.
- a flushing valve 140 was provided in the wall of the container 110, as well as a purging valve 142, only to provide selected initial conditions.
- the membrane unit has an extraction port 122 and a re-introduction port 146, both in the wall of the container 10.
- Gas permeate mostly CO but with smaller amounts of other gases including 0 2 and leaves the extraction port 122, and retentate can be returned to the container through the re-introduction port 146,
- Pumps 150, 152 were provided to drive the membrane unit 130.
- the pumps 150, 152 are powered by 24VDC power supply 154.
- Filters 156 and 158 were provided to filter pump air inputs.
- Analysis chambers were provided at 164, 166 and 168 for gas component monitoring Inside the chamber and for monitoring of gas components at input and output of a membrane unit 130.
- Flowmeters 190 and 1 2 are provided to measure flow into and from membrane unit 130.
- a thermometer 195 was provided to monitor temperature in die container.
- a datalogger was provided at 175 and various A D converters from various items such as thermometer, flowmeters, gas analysis devices, were provided to input to that datalogger at 180.
- Various of die elements were powered by power supply 199.
- FIG. 3 shows a test run where a control algorithm set by controller 8 was such that the membrane unit 130 was run for 15 minutes on maximum draw rate for COj followed by a 15 minute period of a zero draw rate (holding).
- Figures 6 and 7 show one set of test results with the 15 on 15 off algorithm (for the membrane unit) with a feed/sweep pressure differential being 1.5 barg 0 barg.
- Figure 6 shows the gas levels inside the banana bin during a test run where the membrane unit 130 commenced operations while the oxygen level was above a suitable set point (5%) ⁇
- Gas concentration trace 201 is carbon dioxide while trace 202 is oxygen. It can be seen that the oxygen levels stabilised at about 5% while the carbon dioxide levels stabilised at about 796.
- Figure 7 shows the flow rate of carbon dioxide gas through the membrane unit 130 during the test, showing a stabilising of the rate when the membrane unit 130 was scrubbing.
- Figures 8 and 9 show two further sets of test results using the 15 on 15 off algorithm on the membrane unit and a feed/sweep pressure differential of
- Figure 8 shows that the start point for carbon dioxide levels was about 5.5% which then stabilised under the control regime at about 7%.
- Trace 203 shows carbon dioxide and trace 204 shows oxygen. Oxygen levels remained at equilibrium at their start point of about % ⁇
- Figure 9 shows the oxygen and carbon dioxide levels remaining at their start points of about 5% and 7% respectively during a further test.
- Trace 205 showB carbon dioxide and trace 206 shows oxygen.
- Figure 10 shows the result of applying a different control regime for operation of the membrane unit 130.
- the regime applied is 30 minutes on followed by 30 minutes off.
- the pressure differential across feed and sweep ports 194 and 191 was 1.5barg/0.5barg.
- Trace 207 is oxygen and trace 208 is carbon dioxide, The traces show that oxygen is stable at about 5% and carbon dioxide is coming slowly to equilibrium at about 6.5%.
- the above test rig was improved by including a more rigid board to inhibit reduction in volume when a reduction in internal container pressure was experienced.
- the membrane permeability constant was 3250 Barrer for CO z , thickness was 35 ⁇ , membrane permeability constant for Nitrogen was 280 Barrer, membrane permeability constant for Oxygen was 600 Barrer, and for ater vapour it was 36000Barrer.
- Modelling also showed that alteration of die pressure through the membrane unit, affecting the flowrate during the holding step, by a mechanical Interference such as a blockage or other porous item, is useful for causing a holding step and controlling the flow through the membrane unit to facilitate equilibrium conditions.
- the preferred embodiments of the method and apparatus of the present invention utilise a membrane of only moderate CO, selectivity, relative to N 2 and Oa but it is a membrane which is widely available in the size and format required for the purpose of controlling container atmosphere, at a reasonably low cost.
- the advantage of the preferred embodiments of the present invention are that a membrane unit with a low selectivity and low cost can be utilised in a control system utilising controlled introduction of atmospheric air to provide a stable, controlled, suitable atmosphere for reducing respiration of, and extending the life of, respiring goods in transit.
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Life Sciences & Earth Sciences (AREA)
- General Chemical & Material Sciences (AREA)
- Polymers & Plastics (AREA)
- Food Science & Technology (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Nutrition Science (AREA)
- Health & Medical Sciences (AREA)
- Analytical Chemistry (AREA)
- Wood Science & Technology (AREA)
- Zoology (AREA)
- Mechanical Engineering (AREA)
- Separation Using Semi-Permeable Membranes (AREA)
- Packging For Living Organisms, Food Or Medicinal Products That Are Sensitive To Environmental Conditiond (AREA)
Abstract
Description
Claims
Priority Applications (4)
Application Number | Priority Date | Filing Date | Title |
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EP12779318.0A EP2704818A4 (en) | 2011-05-04 | 2012-05-04 | Apparatus and methods for controlling atmospheric gas composition within a container |
AU2012250500A AU2012250500A1 (en) | 2011-05-04 | 2012-05-04 | Apparatus and methods for controlling atmospheric gas composition within a container |
JP2014508651A JP2014522234A (en) | 2011-05-04 | 2012-05-04 | Apparatus and method for controlling atmospheric gas composition in container |
US14/115,260 US20140308409A1 (en) | 2011-05-04 | 2012-05-04 | Apparatus and methods for controlling atmospheric gas composition within a container |
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AU2011901664 | 2011-05-04 | ||
AU2011901664A AU2011901664A0 (en) | 2011-05-04 | Apparatus and methods for controlling atomospheric gas composition within a container |
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WO2012149611A1 true WO2012149611A1 (en) | 2012-11-08 |
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PCT/AU2012/000486 WO2012149611A1 (en) | 2011-05-04 | 2012-05-04 | Apparatus and methods for controlling atmospheric gas composition within a container |
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US (1) | US20140308409A1 (en) |
EP (1) | EP2704818A4 (en) |
JP (1) | JP2014522234A (en) |
AU (1) | AU2012250500A1 (en) |
WO (1) | WO2012149611A1 (en) |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2014066952A1 (en) | 2012-11-01 | 2014-05-08 | Mitsubishi Australia Limited | Improvements in control of gas composition within a container |
WO2017015709A1 (en) | 2015-07-27 | 2017-02-02 | Mitsubishi Australia Ltd | Monitoring state of produce within transport containers |
EP3399262A4 (en) * | 2015-12-29 | 2019-06-19 | Qingdao Haier Joint Stock Co., Ltd | Method for controlling concentration of gas in crisper drawer |
US10820275B2 (en) | 2014-02-21 | 2020-10-27 | Avcatech Pty Ltd | Data communication device and method |
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US20140141139A1 (en) * | 2012-11-19 | 2014-05-22 | Membrane Technology And Research, Inc. | Membrane Separation Process for Controlling Gas Concentrations Within Produce Shipping or Storage Containers |
US20160366919A1 (en) * | 2015-06-16 | 2016-12-22 | Stephen Kyle van Someren Greve | Systems and methods for preservation of perishable substances |
JP6056923B1 (en) * | 2015-08-28 | 2017-01-11 | ダイキン工業株式会社 | Container refrigeration equipment |
US20170311616A1 (en) * | 2016-04-29 | 2017-11-02 | Storage Control Systems, Inc. | Atmospheric pressure control system |
AU2019287506A1 (en) * | 2018-06-14 | 2020-12-24 | Becton, Dickinson And Company | Atmospheric-balanced vacuum for blood gas sample stabilization with an evacuated container |
US11484038B2 (en) | 2018-10-16 | 2022-11-01 | Storage Control Systems, Inc. | Respiration ranking in controlled atmosphere rooms |
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US20090185948A1 (en) * | 2006-08-09 | 2009-07-23 | Gert Jorgensen | Container with controlled atmosphere |
US7866258B2 (en) * | 2003-06-10 | 2011-01-11 | Maersk Container Industri A/S | Apparatus for controlling the composition of gases within a container |
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US6840982B2 (en) * | 2001-03-13 | 2005-01-11 | American Moxie, Llc | Storage device utilizing a differentially permeable membrane to control gaseous content |
US20070065546A1 (en) * | 2005-09-22 | 2007-03-22 | Gert Jorgensen | Controlled atmosphere in a container |
US20130178145A1 (en) * | 2011-07-01 | 2013-07-11 | Chiquita LLC | Controlled atmosphere sea van container including carbon dioxide scrubber curtain |
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2012
- 2012-05-04 EP EP12779318.0A patent/EP2704818A4/en not_active Withdrawn
- 2012-05-04 WO PCT/AU2012/000486 patent/WO2012149611A1/en active Application Filing
- 2012-05-04 AU AU2012250500A patent/AU2012250500A1/en not_active Abandoned
- 2012-05-04 JP JP2014508651A patent/JP2014522234A/en active Pending
- 2012-05-04 US US14/115,260 patent/US20140308409A1/en not_active Abandoned
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US7866258B2 (en) * | 2003-06-10 | 2011-01-11 | Maersk Container Industri A/S | Apparatus for controlling the composition of gases within a container |
US20090185948A1 (en) * | 2006-08-09 | 2009-07-23 | Gert Jorgensen | Container with controlled atmosphere |
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Cited By (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2014066952A1 (en) | 2012-11-01 | 2014-05-08 | Mitsubishi Australia Limited | Improvements in control of gas composition within a container |
EP2922769A4 (en) * | 2012-11-01 | 2016-10-12 | Mitsubishi Australia Ltd | Improvements in control of gas composition within a container |
AU2017225100B2 (en) * | 2012-11-01 | 2019-11-21 | Avcatech Laboratories Pty Ltd | Improvements in Control of Gas Composition within a Container |
US10820275B2 (en) | 2014-02-21 | 2020-10-27 | Avcatech Pty Ltd | Data communication device and method |
WO2017015709A1 (en) | 2015-07-27 | 2017-02-02 | Mitsubishi Australia Ltd | Monitoring state of produce within transport containers |
EP3328749A4 (en) * | 2015-07-27 | 2019-07-31 | Mitsubishi Australia Limited | Monitoring state of produce within transport containers |
EP3399262A4 (en) * | 2015-12-29 | 2019-06-19 | Qingdao Haier Joint Stock Co., Ltd | Method for controlling concentration of gas in crisper drawer |
Also Published As
Publication number | Publication date |
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AU2012250500A1 (en) | 2013-05-02 |
EP2704818A4 (en) | 2014-11-05 |
JP2014522234A (en) | 2014-09-04 |
US20140308409A1 (en) | 2014-10-16 |
EP2704818A1 (en) | 2014-03-12 |
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