CA1219127A - Method and apparatus for reducing the oxygen concentration of air within a preservation room - Google Patents
Method and apparatus for reducing the oxygen concentration of air within a preservation roomInfo
- Publication number
- CA1219127A CA1219127A CA000416560A CA416560A CA1219127A CA 1219127 A CA1219127 A CA 1219127A CA 000416560 A CA000416560 A CA 000416560A CA 416560 A CA416560 A CA 416560A CA 1219127 A CA1219127 A CA 1219127A
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- CA
- Canada
- Prior art keywords
- air
- gas
- heating
- heated
- oxygen concentration
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
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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
- A01—AGRICULTURE; FORESTRY; ANIMAL HUSBANDRY; HUNTING; TRAPPING; FISHING
- A01F—PROCESSING OF HARVESTED PRODUCE; HAY OR STRAW PRESSES; DEVICES FOR STORING AGRICULTURAL OR HORTICULTURAL PRODUCE
- A01F25/00—Storing agricultural or horticultural produce; Hanging-up harvested fruit
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P60/00—Technologies relating to agriculture, livestock or agroalimentary industries
- Y02P60/80—Food processing, e.g. use of renewable energies or variable speed drives in handling, conveying or stacking
- Y02P60/85—Food storage or conservation, e.g. cooling or drying
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- Life Sciences & Earth Sciences (AREA)
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Environmental Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Wood Science & Technology (AREA)
- Zoology (AREA)
- Food Science & Technology (AREA)
- Polymers & Plastics (AREA)
- Feeding, Discharge, Calcimining, Fusing, And Gas-Generation Devices (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE:
A method and apparatus for reducing the oxygen concentration of air within a preservation room such as the ones used for the conservation of fruits or vegetables.
The apparatus comprises a compressor for pumping the air from the preservation room and circulating it through the apparatus, a device for heating the pumped air at a predetermined temperature, a device for mixing an inflammable gas with the air heated at the predetermined temperature, a catalytic combustion chamber wherein the gas is burnt with the oxygen of the heated air thereby producing air having a reduced oxygen concentration, and a spray water cooler for cooling the air with a reduced oxygen concentration before returning it back to the preservation room. The apparatus may also be provided with thermocouples for measuring the temperatures of the heated air and of the air with a reduced oxygen concentration at the outlet of the catalytic chamber and a control circuit for controlling the mixing and heating devices as a function of the two measured tempera-tures. The apparatus may also be provided with a heat exchanger for recovering the heat from the combustion chamber and using it to preheat the air before heating it.
A method and apparatus for reducing the oxygen concentration of air within a preservation room such as the ones used for the conservation of fruits or vegetables.
The apparatus comprises a compressor for pumping the air from the preservation room and circulating it through the apparatus, a device for heating the pumped air at a predetermined temperature, a device for mixing an inflammable gas with the air heated at the predetermined temperature, a catalytic combustion chamber wherein the gas is burnt with the oxygen of the heated air thereby producing air having a reduced oxygen concentration, and a spray water cooler for cooling the air with a reduced oxygen concentration before returning it back to the preservation room. The apparatus may also be provided with thermocouples for measuring the temperatures of the heated air and of the air with a reduced oxygen concentration at the outlet of the catalytic chamber and a control circuit for controlling the mixing and heating devices as a function of the two measured tempera-tures. The apparatus may also be provided with a heat exchanger for recovering the heat from the combustion chamber and using it to preheat the air before heating it.
Description
912~
The present invention relates to an improved method and apparatus for reducing the oxygen concentration of the air within a preservation room such as the ones used for the conservation of fruits or vegetables, in an energically efficient manner.
Apparatuses of the above-mentioned type are already known and commercially available. These known apparatuses are generally efficient but they all have the disadvantage of consuming much energy thereby increasing the costs of preservation of fruits or vegetables. This disadvantage results from the very unefficient way the energy supplied to these apparatuses is used.
An object of the present invention is to provide an improved apparatus which overcomes the above described disadvantage. More particularly, the invention provides an apparatus comprising means for recovering and reusing part of the energy already supplied to and consumed by the apparatus. This apparatus may also be provided with means for measuring temperature and thereby controlling the utilization of the above mentioned consumed energy in a more efficient way.
Another object of the present invention is also to provide a improved method for reducing the oxygen con-centration of air within a preservation room. In accordance with the invention, this improved method comprises the following steps:
- pumping the air from said preservation room;
- pre-heating said pumped air;
- heating said pre-heated air a~ a predetermined temperature;
- mixing an inflammable gas with the air at said predetermined temperature;
- burning said gas with the oxygen of said air within a catalytic chamber, thereby reducing the oxygen concentration of said air;
~ .j ~219~
- cooling said air with a reduced oxygen concen-tration; and - returning said cooled a:ir back to the preserva-tion room;
- where.in said pre-heating step is carried out by heat exchange with the air having a reduced oxygen concentration before it is cooled, and by heat exchange with the air heated through said heating step before it is mixed with the gas.
Advantageously, this method may also comprise the steps of measuring the temperature of the heated air before it is mixed with the gas, measuring the temperature of the air with a reduced oxygen concentration at the outlet of the catalytic chamber, and controlling the air-heating and gas-mixing steps as a function of the two measured temperatures.
According to the present invention, there is also provided an apparatus for reducing the oxygen concentration of air within a preservation room, comprising:
- means for pumping the air from the preservation room and circulating it within said apparatus;
- means for pre-heating said air pumped by the pumping means;
- means for heating the pre-heated air at a predetermined temperature;
- means for mixing an inflammable gas with the air heated at said predetermined temperature;
- a catalytic combustion chamber wherein said gas is burnt with the oxygen of said heated air thereby producing air with a reduced oxygen concentration; and - means for cooling the air with a reduced oxygen concentration before returning it back to the preservation room;
- wherein said pre-heating means comprises a first heat exchanger for heat exchange between the air with a reduced oxygen concentration prior its cooling and the air
The present invention relates to an improved method and apparatus for reducing the oxygen concentration of the air within a preservation room such as the ones used for the conservation of fruits or vegetables, in an energically efficient manner.
Apparatuses of the above-mentioned type are already known and commercially available. These known apparatuses are generally efficient but they all have the disadvantage of consuming much energy thereby increasing the costs of preservation of fruits or vegetables. This disadvantage results from the very unefficient way the energy supplied to these apparatuses is used.
An object of the present invention is to provide an improved apparatus which overcomes the above described disadvantage. More particularly, the invention provides an apparatus comprising means for recovering and reusing part of the energy already supplied to and consumed by the apparatus. This apparatus may also be provided with means for measuring temperature and thereby controlling the utilization of the above mentioned consumed energy in a more efficient way.
Another object of the present invention is also to provide a improved method for reducing the oxygen con-centration of air within a preservation room. In accordance with the invention, this improved method comprises the following steps:
- pumping the air from said preservation room;
- pre-heating said pumped air;
- heating said pre-heated air a~ a predetermined temperature;
- mixing an inflammable gas with the air at said predetermined temperature;
- burning said gas with the oxygen of said air within a catalytic chamber, thereby reducing the oxygen concentration of said air;
~ .j ~219~
- cooling said air with a reduced oxygen concen-tration; and - returning said cooled a:ir back to the preserva-tion room;
- where.in said pre-heating step is carried out by heat exchange with the air having a reduced oxygen concentration before it is cooled, and by heat exchange with the air heated through said heating step before it is mixed with the gas.
Advantageously, this method may also comprise the steps of measuring the temperature of the heated air before it is mixed with the gas, measuring the temperature of the air with a reduced oxygen concentration at the outlet of the catalytic chamber, and controlling the air-heating and gas-mixing steps as a function of the two measured temperatures.
According to the present invention, there is also provided an apparatus for reducing the oxygen concentration of air within a preservation room, comprising:
- means for pumping the air from the preservation room and circulating it within said apparatus;
- means for pre-heating said air pumped by the pumping means;
- means for heating the pre-heated air at a predetermined temperature;
- means for mixing an inflammable gas with the air heated at said predetermined temperature;
- a catalytic combustion chamber wherein said gas is burnt with the oxygen of said heated air thereby producing air with a reduced oxygen concentration; and - means for cooling the air with a reduced oxygen concentration before returning it back to the preservation room;
- wherein said pre-heating means comprises a first heat exchanger for heat exchange between the air with a reduced oxygen concentration prior its cooling and the air
2 --:~219127 pumped by the pumping means, and a second heat exchanger for heat exchange between the air heated by said heating means and the air pumped by the pumping means.
The apparatus may also comprise means for measuring the temperature of the heated air before it is mixed with the gas, means for measuring the temperature of the air with a reduced oxygen concentration at the outlet of the catalytic chamber, and means for controlling the heating means and gas-mixing means as a function of the two measured temperatures.
Preferably, the second heat exchanger is incor-porated to the heating means.
The advantages and other features of the present invention will become apparent from the following non restrictive description of the preferred embodiment thereof, with reference to .he accompanying drawings, in which:
- Figure 1 is a general diagram of the apparatus according to the present invention;
- Figure 2 shows in greater details the gas-mixing means forming part of the apparatus of Figure l;
- Figure 3 shows dia~rammatically the electrical circuit of the apparatus of Figure l; and - E'igure 4 shows the spray water cooler forming part of the apparatus of Figure 1.
The apparatus according to the invention as shown in Figure 1 comprises a compressor 3 pumping the air from the preservation room (not shown) via a first tube 18, a paper filter 81 and a second tube 82. The compressor 3 supplies the pumped air at a pressure that may be of 15 inches of water through a tube 4 to the outer shell of an heat exchanger 85 comprising an inner tube and an outer tube.
The inner tube is preferably made of stainless steel material and the outer tube of steel material. A pressure switch 39 is provided at the outlet of the compressor 3 to stop this ~Z191;27 compressor and switch off the electric power supply of the apparatus as will be explained hereinafter if the pressure at the outlet of the compressor 3 becomes unsufficient.
The heat exchanger 85 heat the air at about 300F and supplies the pre-heated air to a heater 7 through a tube 86. The heater 7 is also provided with an inner tube 21 and an outer tube concentrically disposed with respect to each other. The annular passage defined by these two tubes constitutes a second heat exchanger in which the air comin~
from the heat exchanger 85 is further pre-heated. The bottom of the inner tube 21 is opened and slightly spaced apart from the bottom of the outer tube of the heater 7 which is closed, to direct the air from the annular passage of the heater 7 toward the inner tube 21 as shown by the arrows on Figure 1. Two electrical heating coils are provided and mounted in the inner tube 21 for heating the air pumped by the compressor at 600F. A thermocouple 20 is disposed at the top of the inner tube 21 to measure the temperature of the heated air. It will be seen herein-after that the value of the temperature measured by thethermocouple 20 is used to control the temperature of the heated air at the outlet of the heater 7 by energizing the above-mentioned electrical heating coils.
The air heated at 600 is then supplied through a tube 8 to a catalytic combustion chamber 10. Before entering the chamber 10, the heated air is mixed with propane. The mixture is made by introduction of the gas by means of a gas diffusor 9 inserted into the tube 8.
The catalytic chamber 10 is filled up with an aluminium and platimiun oxyde catalyst which produces an auto combustion reaction of the propane mixed in the heated air with the oxygen of the air at about 600F. The reaction of the oxygen of the air with propane in the combustion reaction reduces the concentration of oxygen down to 2 to 3% and 12~9~
raises the temperature of the air to about 1200F. The inlet and outlet of the catalytic chamber 10, and the tubes 8 and 13 are provided with connecting flanges 91 that can be unbolted to remove the catalytic chamber from the apparatus for maintenance whenever necessary. Advantageously, the catalytic combustion chamber is dismountable to permit the replacement of the inner material only instead of the complete chamber, thereby reducing the maintenance costs.
A thermocouple 92 is provided at the outlet of the catalytic chamber 10 to measure the temperature of the air with a reduced oxygen concentration. It will be seen hereinafter that this measured temperature is used for controlling the energization of the electrical heating coils within the inner tube 21 and for opening a solenoid valve 23 shown in figure 2 to supply propane to the diffusor 9.
The air with a reduced oxygen concentration at 1200F obtained at the outlet of the catalytic oombustion chamber 10 is supplied through a tube 13 to the inner tube of the heat exchanger 85 wherein it exchanges its heat with the air pumped by the compressor 3 in the outer shell of the heat exchanger 85 therebyraising the temperature of the air within this outer shell to about 3nOF at the out-put of this outer shell, as indicated hereinabove.
The air having a reduced oxygen concentration is then supplied through a tube 94 to the bottom of the housing of a spray water cooler 15 where it is cooled. The air with a reduced oxygen concentration circulates inside the cooler 15 from bottom to top and is subsequently returned to the preservation room through a tube 17. The cooler 15 is provided with a water spray 96 which sprays water onto the air inside the housing, and with a water drain 22 for evacua-tion of the water sprayed for cooling the air with a reduced oxygen concentration before it is returned back to the pre-servation room. The tube 94 is also provided with connecting ~Z19127 flanges 91 of the same type as described above for facili-tating maintenance.
A thermostat 40 is disposed within the tube 17.
As will be seen hereinafter, this thermostat is used for controling power supply to the apparatus.
Figure 2 of the drawings shows in details the gas-diffusor 9 mentioned hereinabove. This gas-diffusor is provided with a solenoid valve 23 controlling the admission of propane from a propane pressurized bottle. The diffusor 9 is mounted on the tube 8 for mixing the propane with the heated air from the heater 7. The propane is admitted through the solenoid valve 23 to a differential gas flow regulator 24 supplying gas to the diffusor 9 directly through a conduct 90 or vi~an adjustable gas flow regulator 25. This gas flow system is used for controling the gas flow from the propane press~lrized bottle to the diffusor 9.
Figure 3 of the drawings shows the electrical circuit of the invention. It should be noted that this electrical circuit incorporates a particular circuit auto-matically controlling the operation of the apparatus.
The electrical circuit shown on figure 3 is sup-plied by a 240 volts A.C. source 50 connected to a first contactor 27 provided with a solenoid coil 27a closing the contacts of contactor 27 when energized. An automatic disconnecting switch 28 is also provided to switchoff the current through the coil 27a, thereby opening the two contacts of the contactor 27, when opening the door of the cabinet containing the electrical system for an improved maintenance safety. A manual disconnecting switch 29 permits to manually close or open the two contacts of con-tactor 27 by respectively activating or desactiviting the coil 27a when the door of the cabinet is closed. The coil 27a is connected at one terminal to a lead 26 (passive lead or negative terminal) of the source 50 and at the other ~2~9127 terminal to the ground by the intermediary of the two switches 28 and 29 and the connecting point 61 of a terminal board. The two contacts of the contactor 27 supply electric power from the source 50 to the electrical system when closed (as shown on figure 3).
More particularly, the two contacts of contactor 27, when closed, supply a transformer 37 (220-230/110-115 V) and contactors 34, 35 and 36.
The two terminals of the secondary of the trans-former 37 are respectively connected through two fuses 43 (2 amperes fuses for example) to a pair of connectin~ points 64 and 65 of the terminal board 60. The connecting points of the terminal board 60 will be referred to hereinafter as poi~nts.
Points 63 and 65 of the terminal board 60 are each connected to One terminal of a solenoid coil 36a and supplies with electrical power the control circuit. Point 63 is connected to point 64, which is connected to the secondary terminal of the transformer 37, through a thermostat 40 and a pressure switch 39. The energization of coi~ 36a closes the two contact of a air compressor contactor 36 thereby supplying electric power to the air compressor 3.
The thermostat 40 (mounted between points 62 and 63) responsive to the temperature of the cooled air at the outlet 17 keeps the circuit supplying the coil 36a and the control circuit closed at a preset temperature (60F) of the air having a reduced oxygen concentration after it has been cooled and before it is supplied to the preservation room. The pressure switch 39 (mounted between points 62 and 64) is provided for safety purpose, to switch off and thereby stop supplying the compressor and control circuit when the pressure at the outlet of the compressor 3 is lower than a predetermined value which means that the compressor does not normally work.
A push-button starter 38 is mounted in parallel to the ~2~91Z'I~
pressure switch 39 for by-passing the switch 39 when s-tarting the compressor 3, until the operational pressure is obtained (about 15 inches of water) and the pressure switch 39 is closed for a normal operation.
The -transformer 37 is also connected to point 71 by a wire 74 connecting point 65 to point 71. An other wire 75 connects points 63 and 73 thereby supplying voltage to point 73.
The control circuit comprises a two points, temperature switch 30. The thermocouple 92 (shown in figure 1) has its two terminals respectively connected to terminals 1 and 2 of the switch 30 thereby supplying the voltage appearing through the thermocouple 92 to this switch.
The first temperature point or first temperature level measured by the thermocouple 92 acts on the switch 30 to energize the solenold 33 through point 71 and terminal 6 of the switch 30. The second temperature point or second temperature level measured by the thermocouple 92 acts on the switch 30 to energize the propane solenoid valve 23 (see figure 2) through point 71 and terminal 1~ of switch 30.
The transformer 37 is also connected to terminals 5, 11 and 16 of the switch 30 by point 63 and to terminal 12 by point 65.
Upon activation of the coil 33, the contacts 32a and 32b of contactor 32 close and respectivel~ connect the transformer 37 from point 73 to point 68 and from point 71 to point 69. As illustrated on figure 3, terminals 11, 12 and 6 of a one point temperature controller 31 forming part of the control circuit are respectively supplied by points 68, 69 and 71. The contactor 34 is permanently activated, when contactor 32 is energized, by the solenoid coil 34a through point 69, point 70, switch 42 and point 68. The thermocouple 20 (shown in figure 1) has its two terminals respectively connected to terminals 1 and 2 of the controller ~;~1912'7 31. The measured temperature, or voltage appearing through thermocouple 20, acts on controller 31 to sequentially activate the solenoid coil 35a through point 68 and terminal 5 of controller 31, thereby closing the contacts of the contactor 35.
The contactors 34 and 35 respectively supply electrical power to a permanent heating coil 41b and sequential heating coil 4la both mounted in the inner tube of the heater 7 of figure 1. The sequential coil is energized only when supplementary heat is needed to maintain or control the temperature of the heated air at 600E. A manual disconnect-ing switch 42 is provided to manually switchoff the coil 34a of the contactor 34 for stopping supplying power to coil 41b.
The switch 30 may be a Honeywell CB 301 switch and the controller 31 a Honeywell AB 301 controller (Trademarks).
Figure 4 of the drawings shows in details the spray water cooler 15. As can be seen, the water is supplied by a water inlet pipe 44 to a water spray 96 by means of a water pressure re~ulator 45. The water pressure regulator 45 adjusts the pressure of the water supplied to the water spray 96 at about 35 psi. This type of cooler advantageously reduces the consumption of water.
Obviously, the object of the present invention is not restricted to the above described preferred embodiment.
Some features can be modified, for example replacement of propane gas with other inflammable gas, substitution of aluminium and platinium catalist with other types of catalist material, change in the exact shape or type of the elements constituting the apparatus, etc... Of course, such modifi-cations would not change the scope and nature of the presentinvention.
_ g _
The apparatus may also comprise means for measuring the temperature of the heated air before it is mixed with the gas, means for measuring the temperature of the air with a reduced oxygen concentration at the outlet of the catalytic chamber, and means for controlling the heating means and gas-mixing means as a function of the two measured temperatures.
Preferably, the second heat exchanger is incor-porated to the heating means.
The advantages and other features of the present invention will become apparent from the following non restrictive description of the preferred embodiment thereof, with reference to .he accompanying drawings, in which:
- Figure 1 is a general diagram of the apparatus according to the present invention;
- Figure 2 shows in greater details the gas-mixing means forming part of the apparatus of Figure l;
- Figure 3 shows dia~rammatically the electrical circuit of the apparatus of Figure l; and - E'igure 4 shows the spray water cooler forming part of the apparatus of Figure 1.
The apparatus according to the invention as shown in Figure 1 comprises a compressor 3 pumping the air from the preservation room (not shown) via a first tube 18, a paper filter 81 and a second tube 82. The compressor 3 supplies the pumped air at a pressure that may be of 15 inches of water through a tube 4 to the outer shell of an heat exchanger 85 comprising an inner tube and an outer tube.
The inner tube is preferably made of stainless steel material and the outer tube of steel material. A pressure switch 39 is provided at the outlet of the compressor 3 to stop this ~Z191;27 compressor and switch off the electric power supply of the apparatus as will be explained hereinafter if the pressure at the outlet of the compressor 3 becomes unsufficient.
The heat exchanger 85 heat the air at about 300F and supplies the pre-heated air to a heater 7 through a tube 86. The heater 7 is also provided with an inner tube 21 and an outer tube concentrically disposed with respect to each other. The annular passage defined by these two tubes constitutes a second heat exchanger in which the air comin~
from the heat exchanger 85 is further pre-heated. The bottom of the inner tube 21 is opened and slightly spaced apart from the bottom of the outer tube of the heater 7 which is closed, to direct the air from the annular passage of the heater 7 toward the inner tube 21 as shown by the arrows on Figure 1. Two electrical heating coils are provided and mounted in the inner tube 21 for heating the air pumped by the compressor at 600F. A thermocouple 20 is disposed at the top of the inner tube 21 to measure the temperature of the heated air. It will be seen herein-after that the value of the temperature measured by thethermocouple 20 is used to control the temperature of the heated air at the outlet of the heater 7 by energizing the above-mentioned electrical heating coils.
The air heated at 600 is then supplied through a tube 8 to a catalytic combustion chamber 10. Before entering the chamber 10, the heated air is mixed with propane. The mixture is made by introduction of the gas by means of a gas diffusor 9 inserted into the tube 8.
The catalytic chamber 10 is filled up with an aluminium and platimiun oxyde catalyst which produces an auto combustion reaction of the propane mixed in the heated air with the oxygen of the air at about 600F. The reaction of the oxygen of the air with propane in the combustion reaction reduces the concentration of oxygen down to 2 to 3% and 12~9~
raises the temperature of the air to about 1200F. The inlet and outlet of the catalytic chamber 10, and the tubes 8 and 13 are provided with connecting flanges 91 that can be unbolted to remove the catalytic chamber from the apparatus for maintenance whenever necessary. Advantageously, the catalytic combustion chamber is dismountable to permit the replacement of the inner material only instead of the complete chamber, thereby reducing the maintenance costs.
A thermocouple 92 is provided at the outlet of the catalytic chamber 10 to measure the temperature of the air with a reduced oxygen concentration. It will be seen hereinafter that this measured temperature is used for controlling the energization of the electrical heating coils within the inner tube 21 and for opening a solenoid valve 23 shown in figure 2 to supply propane to the diffusor 9.
The air with a reduced oxygen concentration at 1200F obtained at the outlet of the catalytic oombustion chamber 10 is supplied through a tube 13 to the inner tube of the heat exchanger 85 wherein it exchanges its heat with the air pumped by the compressor 3 in the outer shell of the heat exchanger 85 therebyraising the temperature of the air within this outer shell to about 3nOF at the out-put of this outer shell, as indicated hereinabove.
The air having a reduced oxygen concentration is then supplied through a tube 94 to the bottom of the housing of a spray water cooler 15 where it is cooled. The air with a reduced oxygen concentration circulates inside the cooler 15 from bottom to top and is subsequently returned to the preservation room through a tube 17. The cooler 15 is provided with a water spray 96 which sprays water onto the air inside the housing, and with a water drain 22 for evacua-tion of the water sprayed for cooling the air with a reduced oxygen concentration before it is returned back to the pre-servation room. The tube 94 is also provided with connecting ~Z19127 flanges 91 of the same type as described above for facili-tating maintenance.
A thermostat 40 is disposed within the tube 17.
As will be seen hereinafter, this thermostat is used for controling power supply to the apparatus.
Figure 2 of the drawings shows in details the gas-diffusor 9 mentioned hereinabove. This gas-diffusor is provided with a solenoid valve 23 controlling the admission of propane from a propane pressurized bottle. The diffusor 9 is mounted on the tube 8 for mixing the propane with the heated air from the heater 7. The propane is admitted through the solenoid valve 23 to a differential gas flow regulator 24 supplying gas to the diffusor 9 directly through a conduct 90 or vi~an adjustable gas flow regulator 25. This gas flow system is used for controling the gas flow from the propane press~lrized bottle to the diffusor 9.
Figure 3 of the drawings shows the electrical circuit of the invention. It should be noted that this electrical circuit incorporates a particular circuit auto-matically controlling the operation of the apparatus.
The electrical circuit shown on figure 3 is sup-plied by a 240 volts A.C. source 50 connected to a first contactor 27 provided with a solenoid coil 27a closing the contacts of contactor 27 when energized. An automatic disconnecting switch 28 is also provided to switchoff the current through the coil 27a, thereby opening the two contacts of the contactor 27, when opening the door of the cabinet containing the electrical system for an improved maintenance safety. A manual disconnecting switch 29 permits to manually close or open the two contacts of con-tactor 27 by respectively activating or desactiviting the coil 27a when the door of the cabinet is closed. The coil 27a is connected at one terminal to a lead 26 (passive lead or negative terminal) of the source 50 and at the other ~2~9127 terminal to the ground by the intermediary of the two switches 28 and 29 and the connecting point 61 of a terminal board. The two contacts of the contactor 27 supply electric power from the source 50 to the electrical system when closed (as shown on figure 3).
More particularly, the two contacts of contactor 27, when closed, supply a transformer 37 (220-230/110-115 V) and contactors 34, 35 and 36.
The two terminals of the secondary of the trans-former 37 are respectively connected through two fuses 43 (2 amperes fuses for example) to a pair of connectin~ points 64 and 65 of the terminal board 60. The connecting points of the terminal board 60 will be referred to hereinafter as poi~nts.
Points 63 and 65 of the terminal board 60 are each connected to One terminal of a solenoid coil 36a and supplies with electrical power the control circuit. Point 63 is connected to point 64, which is connected to the secondary terminal of the transformer 37, through a thermostat 40 and a pressure switch 39. The energization of coi~ 36a closes the two contact of a air compressor contactor 36 thereby supplying electric power to the air compressor 3.
The thermostat 40 (mounted between points 62 and 63) responsive to the temperature of the cooled air at the outlet 17 keeps the circuit supplying the coil 36a and the control circuit closed at a preset temperature (60F) of the air having a reduced oxygen concentration after it has been cooled and before it is supplied to the preservation room. The pressure switch 39 (mounted between points 62 and 64) is provided for safety purpose, to switch off and thereby stop supplying the compressor and control circuit when the pressure at the outlet of the compressor 3 is lower than a predetermined value which means that the compressor does not normally work.
A push-button starter 38 is mounted in parallel to the ~2~91Z'I~
pressure switch 39 for by-passing the switch 39 when s-tarting the compressor 3, until the operational pressure is obtained (about 15 inches of water) and the pressure switch 39 is closed for a normal operation.
The -transformer 37 is also connected to point 71 by a wire 74 connecting point 65 to point 71. An other wire 75 connects points 63 and 73 thereby supplying voltage to point 73.
The control circuit comprises a two points, temperature switch 30. The thermocouple 92 (shown in figure 1) has its two terminals respectively connected to terminals 1 and 2 of the switch 30 thereby supplying the voltage appearing through the thermocouple 92 to this switch.
The first temperature point or first temperature level measured by the thermocouple 92 acts on the switch 30 to energize the solenold 33 through point 71 and terminal 6 of the switch 30. The second temperature point or second temperature level measured by the thermocouple 92 acts on the switch 30 to energize the propane solenoid valve 23 (see figure 2) through point 71 and terminal 1~ of switch 30.
The transformer 37 is also connected to terminals 5, 11 and 16 of the switch 30 by point 63 and to terminal 12 by point 65.
Upon activation of the coil 33, the contacts 32a and 32b of contactor 32 close and respectivel~ connect the transformer 37 from point 73 to point 68 and from point 71 to point 69. As illustrated on figure 3, terminals 11, 12 and 6 of a one point temperature controller 31 forming part of the control circuit are respectively supplied by points 68, 69 and 71. The contactor 34 is permanently activated, when contactor 32 is energized, by the solenoid coil 34a through point 69, point 70, switch 42 and point 68. The thermocouple 20 (shown in figure 1) has its two terminals respectively connected to terminals 1 and 2 of the controller ~;~1912'7 31. The measured temperature, or voltage appearing through thermocouple 20, acts on controller 31 to sequentially activate the solenoid coil 35a through point 68 and terminal 5 of controller 31, thereby closing the contacts of the contactor 35.
The contactors 34 and 35 respectively supply electrical power to a permanent heating coil 41b and sequential heating coil 4la both mounted in the inner tube of the heater 7 of figure 1. The sequential coil is energized only when supplementary heat is needed to maintain or control the temperature of the heated air at 600E. A manual disconnect-ing switch 42 is provided to manually switchoff the coil 34a of the contactor 34 for stopping supplying power to coil 41b.
The switch 30 may be a Honeywell CB 301 switch and the controller 31 a Honeywell AB 301 controller (Trademarks).
Figure 4 of the drawings shows in details the spray water cooler 15. As can be seen, the water is supplied by a water inlet pipe 44 to a water spray 96 by means of a water pressure re~ulator 45. The water pressure regulator 45 adjusts the pressure of the water supplied to the water spray 96 at about 35 psi. This type of cooler advantageously reduces the consumption of water.
Obviously, the object of the present invention is not restricted to the above described preferred embodiment.
Some features can be modified, for example replacement of propane gas with other inflammable gas, substitution of aluminium and platinium catalist with other types of catalist material, change in the exact shape or type of the elements constituting the apparatus, etc... Of course, such modifi-cations would not change the scope and nature of the presentinvention.
_ g _
Claims (20)
1. A method for reducing the oxygen concentration of air within a preservation room, said method comprising the steps of:
- pumping the air from said preservation room;
- pre-heating said pumped air;
- heating said pre-heated air at a predetermined temperature;
- mixing an inflammable gas with the air at said predetermined temperature;
- burning said gas with the oxygen of said air within a catalytic chamber, thereby reducing the oxygen concentration of said air;
- cooling said air with a reduced oxygen concen-tration; and - returning said cooled air back to the preserva-tion room;
- wherein said pre-heating step is carried out by heat exchange with the air having a reduced oxygen con-centration before it is cooled, and by heat exchange with the air heated through said heating step before it is mixed with the gas.
- pumping the air from said preservation room;
- pre-heating said pumped air;
- heating said pre-heated air at a predetermined temperature;
- mixing an inflammable gas with the air at said predetermined temperature;
- burning said gas with the oxygen of said air within a catalytic chamber, thereby reducing the oxygen concentration of said air;
- cooling said air with a reduced oxygen concen-tration; and - returning said cooled air back to the preserva-tion room;
- wherein said pre-heating step is carried out by heat exchange with the air having a reduced oxygen con-centration before it is cooled, and by heat exchange with the air heated through said heating step before it is mixed with the gas.
2. The method of claim 1, comprising the steps of:
- measuring the temperature of the heated air before it is mixed with said gas;
- measuring the temperature of said air with a reduced oxygen concentration at the outlet of the catalytic chamber; and - controlling said air-heating and gas-mixing steps as a function of the two measured temperatures.
- measuring the temperature of the heated air before it is mixed with said gas;
- measuring the temperature of said air with a reduced oxygen concentration at the outlet of the catalytic chamber; and - controlling said air-heating and gas-mixing steps as a function of the two measured temperatures.
3. The method of claim 2, further comprising the step of filtering the air from the preservation room.
4. A method according to claim 2, wherein the cooling step is carried out by spraying water onto the air with a reduced oxygen concentration.
5. An apparatus for reducing the oxygen concen-tration of air within a preservation room, comprising:
- means for pumping the air from the preservation room and circulating it within said apparatus;
- means for pre-heating said air pumped by the pumping means;
- means for heating the pre-heated air at a predetermined temperature;
- means for mixing an inflammable gas with the air heated at said predetermined temperature;
- a catalytic combustion chamber wherein said gas is burnt with the oxygen of said heated air thereby producing air with a reduced oxygen concentration; and - means for cooling the air with a reduced oxygen concentration before returning it back to the preservation room;
- wherein said pre-heating means comprises a first heat exchanger for heat exchange between the air with a reduced oxygen concentration prior its cooling and the air pumped by the pumping means, and a second heat exchanger for heat exchange between the air heated by said heating means and the air pumped by the pumping means.
- means for pumping the air from the preservation room and circulating it within said apparatus;
- means for pre-heating said air pumped by the pumping means;
- means for heating the pre-heated air at a predetermined temperature;
- means for mixing an inflammable gas with the air heated at said predetermined temperature;
- a catalytic combustion chamber wherein said gas is burnt with the oxygen of said heated air thereby producing air with a reduced oxygen concentration; and - means for cooling the air with a reduced oxygen concentration before returning it back to the preservation room;
- wherein said pre-heating means comprises a first heat exchanger for heat exchange between the air with a reduced oxygen concentration prior its cooling and the air pumped by the pumping means, and a second heat exchanger for heat exchange between the air heated by said heating means and the air pumped by the pumping means.
6. The apparatus of claim 5, comprising:
- means for measuring the temperature of said heated air before it is mixed with said gas;
- means for measuring the temperature of said air with a reduced oxygen concentration at the outlet of said catalytic chamber; and - means for controlling said heating means and gas-mixing means as a function of the two measured temperatures.
- means for measuring the temperature of said heated air before it is mixed with said gas;
- means for measuring the temperature of said air with a reduced oxygen concentration at the outlet of said catalytic chamber; and - means for controlling said heating means and gas-mixing means as a function of the two measured temperatures.
7. The apparatus according to claim 6, further comprising a filter for filtering said air from the preser-vation room.
8. The apparatus of claim 6, wherein said first heat exchanger comprises an inner tube in which said air with a reduced oxygen concentration circulates and an outer tube concentrically mounted around the inner tube, said outer tube defining with the inner one an annular passage in which the pumped air to be pre-heated circulates.
9. The apparatus of claim 6, wherein said second heat exchanger is incorporated to said heating means.
10. The apparatus of claim 9, wherein said heating means comprises a pair of inner and outer tubes con-centrically disposed with respect to each other so as to define an annular passage, said pumped air circulating through said annular passage defined by said tubes where it is pre-heated, and therefrom through the inner tube where it is heated.
11. The apparatus of claim 10, wherein the inner tube comprises electrical heating elements for heating the air passing therethrough.
12. The apparatus of claim 5, wherein the heating means comprises at least two electrical heating elements.
13. An apparatus according to claim 6, wherein the gas-mixing means comprises:
- a solenoid gas valve connected to a gas supply and controlled by said controlling means;
- a gas diffusor for mixing said gas with the air heated at said predetermined temperature;
- an adjustable gas flow regulator supplying the gas to the diffusor; and - a differential gas flow regulator for supplying said gas from the solenoid gas valve directly to the diffusor and for supplying said gas to the diffusor by the intermediary of the adjustable gas flow regulator.
- a solenoid gas valve connected to a gas supply and controlled by said controlling means;
- a gas diffusor for mixing said gas with the air heated at said predetermined temperature;
- an adjustable gas flow regulator supplying the gas to the diffusor; and - a differential gas flow regulator for supplying said gas from the solenoid gas valve directly to the diffusor and for supplying said gas to the diffusor by the intermediary of the adjustable gas flow regulator.
14. The apparatus of claim 5, wherein said gas is propane.
15. The apparatus of claim 5, wherein said catalytic chamber contains an aluminium and platinum oxide catalist.
16. The apparatus of claim 5 or 6, wherein the cooling means comprises:
- a vertical cylindrical housing;
- a water inlet pipe;
- a water pressure regulator connected to the water inlet pipe;
- a water spray supplied by the water pressure regulator to spray water within said housing;
- an inlet pipe mounted on the lower part of said housing for supplying said air with a reduced oxygen con-centration inside the housing;
- an outlet pipe mounted on the upper part of said housing for returning the cooled air to the preservation room; and - a water drain tube located at the bottom of said housing for evacuating the sprayed water.
- a vertical cylindrical housing;
- a water inlet pipe;
- a water pressure regulator connected to the water inlet pipe;
- a water spray supplied by the water pressure regulator to spray water within said housing;
- an inlet pipe mounted on the lower part of said housing for supplying said air with a reduced oxygen con-centration inside the housing;
- an outlet pipe mounted on the upper part of said housing for returning the cooled air to the preservation room; and - a water drain tube located at the bottom of said housing for evacuating the sprayed water.
17. The apparatus of claim 6, wherein said temperature measuring means are two thermocouples, one of the thermocouples being mounted at the outlet of the catalytic chamber, the other being mounted in said heating means.
18. The apparatus of claim 6 t wherein said controlling means comprise:
- a two point electrical temperature switch responsive to said measured temperature at the outlet of the catalytic chamber to activate a first contactor and a solenoid valve supplying said gas to said mixing means;
- a second contactor responsive to said first contactor for permanently supplying power to said heating means; and - a temperature controller responsive to said first contactor for sequentially activating a third contactor thereby sequentially supplying additional power to said heating means in response to the measured temperature of the heated air.
- a two point electrical temperature switch responsive to said measured temperature at the outlet of the catalytic chamber to activate a first contactor and a solenoid valve supplying said gas to said mixing means;
- a second contactor responsive to said first contactor for permanently supplying power to said heating means; and - a temperature controller responsive to said first contactor for sequentially activating a third contactor thereby sequentially supplying additional power to said heating means in response to the measured temperature of the heated air.
19. The apparatus of claim 18, further comprising a manual switch for manually disconnecting said second contactor.
20. An apparatus according to claim 6, further comprising:
- a thermostat for switching off said controlling and pumping means when the temperature of the cooled air exceeds a pre-set value; and - a pressure switch for switching off said controlling and pumping means when the pressure within said apparatus is lower than a preset value.
- a thermostat for switching off said controlling and pumping means when the temperature of the cooled air exceeds a pre-set value; and - a pressure switch for switching off said controlling and pumping means when the pressure within said apparatus is lower than a preset value.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000416560A CA1219127A (en) | 1982-11-29 | 1982-11-29 | Method and apparatus for reducing the oxygen concentration of air within a preservation room |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000416560A CA1219127A (en) | 1982-11-29 | 1982-11-29 | Method and apparatus for reducing the oxygen concentration of air within a preservation room |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1219127A true CA1219127A (en) | 1987-03-17 |
Family
ID=4124040
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000416560A Expired CA1219127A (en) | 1982-11-29 | 1982-11-29 | Method and apparatus for reducing the oxygen concentration of air within a preservation room |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1219127A (en) |
-
1982
- 1982-11-29 CA CA000416560A patent/CA1219127A/en not_active Expired
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