|Publication number||US3453085 A|
|Publication date||Jul 1, 1969|
|Filing date||Jun 26, 1964|
|Priority date||Jun 26, 1964|
|Publication number||US 3453085 A, US 3453085A, US-A-3453085, US3453085 A, US3453085A|
|Inventors||Lannert James W, Schrage David W, Townsend George E|
|Original Assignee||Whirlpool Co|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (4), Referenced by (4), Classifications (13)|
|External Links: USPTO, USPTO Assignment, Espacenet|
July 1, 1969 J, w, LANNERT ET AL l DIOXIDE ATMOSPHERE Sheet .of 5
' Filed June 26, 1964 I IMWZWDM Illm 0| L w ww W @L Nl .K wOwD e A.. k e@ gw. i, m2 NW S mw 1 a. w J@ Nw Hw L Nw Nk x .\m.% s uw ww July 1,v 1969 J. w. LANNERT ET AL 3,453,085 APPARATUS PoR PROVIDING AN OXYGEN-CARBON DxoxIDE ATMOSPHERE Filed June 26, 1964 Sheet 2 of 5 vAwP MoToRs 02 14H5 157 July l 1969 J. w. Lnmmawr -E'r AL 3,453,085
' APPARATUS FOR PROVIDING AN OXYGEN-CARBON I DIOXIDE ATMOSPHERE Filed June 26, 1964 4 sheet 3 afs4 July l, 1969 1. w. LANNERT ET AL 3,453,085
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3 jcoyj.; 1N BuRl/? OUTLET '20( 111 o 4;'92 #Rom ADSORBER f I I l ,o 'mom Ansonsten lo z o Q 2 I U 921m AITE N i GASES ARE MASURED o 8 L ffm IIa- AT ou'rLE-r or jg Ausones 7 101 102 107 6 O-75 ..8 511-525 r .100 Pomr on cuzvcrr wenn: n CYCLE TIMER SWITCHES TO 5 New CYCLE 4 2.45-, 5 BREAK-'rueoueH PomT oF I Absonsksj 2 k Lum rm0 85% fN o n 2 a 4 5 e 7 g s n ua s4 United States Patent O M 3,453,085 APPARATUS FOR PROVIDING AN OXYGEN- CARBON DIOXIDE ATMOSPHERE James W. Lannert, St. Joseph, George E. Townsend,
Stevensville, and David W. Schrage, Berrien Center, Mich., assignors to Whirlpool Corporation, a corporation of Delaware Filed June 26, 1964, Ser. No. 378,148 Int. Cl. B01j 7/00; A231 3/00, 3/34 U.S. Cl. 23-281 17 Claims ABSTRACT F THE DISCLOSURE An apparatus for supplying to a receiver a mixture of a -lirst fluid such as carbon dioxide and a second iluid such as oxygen in 'which the iirst fluid from its source is directed by passage means to a receiver through a holding means in the passage means for retaining a predetermined maximum amount of the first fluid 'and for storing the second fluid together with means for flowing the lirst fluid from a source thereof through the holding means to the receiver in an amount in excess of a maximum amount that the receiver is capable of holding to supply this excess amount of first fluid to the receiver and simultaneous- 1y transfer the stored second fluid to the receiver. In a particular embodiment the receiver is ya room for storing vegetable and animal materials, the holding means is an adsorber for releasably retaining carbon dioxide and the source of the second fluid is a blower for supplying air.
This invention relates to an apparatus for producing and maintaining in a receiver an atmosphere having preselected controlled amounts of a lirst iluid, for example carbon dioxide, and a second iluid, for example oxygen.
One of the features of this invention is to provide an improved apparatus for producing and maintaining an atmosphere having preselected controlled amounts of a first fluid and a second fluid for a receiver such as a storage chamber in which animal and vegetable materials may be stored, in which case the first lluid would be carbon ldioxide and the second fluid oxygen.
Another feature of the invention is to provide an improved automatic control apparatus for providing automatic maintenance of the preselected proportion of iirst and second fluids under the desired controlled conditions and in which these conditions can be altered as desired.
Other features and advantages of the invention will be apparent from the following description thereof, particularly as illustrated in the embodiment shown in the accompanying drawings. Of the drawings:
FIGURE l is a semi-diagrammatic view showing the relationship of the parts of this embodiment of the atmos phere producing apparatus.
FIGURE 2 is a schematic wiring diagram of the electrical circuit portion of the apparatus showing the parts of the automatic control.
FIGURE 3 is an enlarged detail of a portion of the electrical circuit of FIGURE 2.
FIGURE 4 is a graph illustrating how the Operating conditions may be changed with a typical atmosphere generator to produce desired amounts of carbon dioxide land oxygen.
FIGURE 5 is a graph illustrating changing oxygen and carbon dioxide concentrations to maintain a preselected oxygen level, here 2%, and carbon dioxide level, here 4%, in a storage chamber.
In Bedrosian et al. Patent 3,102,777, assigned to the same Iassignee as the present application, there is disclosed and claimed an apparatus and method for providing an atmosphere with controlled amounts of oxygen and carbon dioxide which may be used to provide a storage atmos- 3,453,085 Patented July 1, 1969 ACC phere in a receiver, such as a storage chamber, for the preservation of animal and vegetable materials'. ln the copending Lannert et al. application Ser. No. 213,398, filed July 30, 1962, now Patent 3,205,049 also assigned to the same assignee, there is disclosed and claimed one form of an apparatus for producing and maintaining such an atmosphere. Another form of apparatus is disclosed in Thomas et al. application Ser. No. 321,626, led Nov. 5, 1963, and also assigned to the same assignee.
The present invention is a further development in this field and also utilizes a catalytic burner generator with a pair of activated carbon adsorbers with one being used to adsorb undesirable gases such as, for example, ethylene and controlled amounts of carbon dioxide, while the other is being regenerated by removing the adsorbed undesirable gases and carbon dioxide. The apparatus of this invention Ialso utilizes a pair of variable timers with one being used to control the amount of oxygen provided to the receiver or storage chamber and the other regulating the amount of carbon dioxide provided to the receiver with both timers being readily adjustable so as to vary the amounts of these two gases to desired predetermined amounts.
Although the apparatus of this invention utilizes substantially the same units of equipment as disclosed and claimed in the above Thomas et al. application, suiicent changes are made so that the apparatus as a whole operates in a different manner.
Thus, in the 'apparatus of the present invention the carbon dioxide rich gases from the generator are conducted through the adsorber at all times except for the start-up period when these gases are briefly conducted to a place of disposal such as the atmosphere because they may contain unburned fuel and other undesirable products. After this initial period, however, they are directed through the adsorber throughout the entire cycle period including an additional period during which the cycle timer operation is interrupted and gases low in carbon dioxide are fed from the adsorber into the storage chamber or receiver as describedvhereinafter.
As is explained in the above Thomas et al. application, each adsorber at the beginning of its cycle contains air which Was used previously to reactivate the adsorber by removing adsorbed carbon dioxide. Thus, at the beginning the adsorber contains a maximum amount of oxygen which is substantially the same for the beginning of each cycle.
Then, the gases from the generator are directed through the adsorber and to a place of disposal such as the ambient atmosphere for a predetermined time period as set on the adjustable time oxygen timer to remove all but a predetermined amount of oxygen from the adsorber and adsorbent. This predetermined time period is designated as the purge period. The cycle timer which operates for a fixed period, such as six minutes, operates during this purging period.
Then the carbon dioxide timer goes into operation and functions for a predetermined time period which is set on the adjustable carbon dioxide timer to direct the gases from the adsorber into the storage chamber. During the initial part of this period the gases are substantially carbon dioxide free as the adsorber removes carbon dioxide from the generator gases. The length of the carbon dioxide adsorbing period is a function of the carbon dioxide concentration in the eiuent of the generator and the amount and type of adsorbent material. At the same time, the oxygen remaining in the adsorber and adsorbent is transferred by the gases into the chamber to give the desired preselected oxygen content to the chamber atmos phere. During this operation of the carbon dioxide timer the cycle timer is stopped so that when it resumes again it will continue for the amount of time left on it from the above described purging operation,
Finally, the carbon dioxide timer automatically stops operation at the end of its preset time and the cycle timer automatically resumes operation for the remaining time left on its preset period to continue to ow gases from the generator through the adsorber into the storage chamber for this remaining time. After the adsorber has become saturated with carbon dioxide, the summation of time on the carbon dioxide timer and the remaining time on the cycle timer is suicient to supply some carbon dioxide rich gas to the storage chamber.
Thus, as was mentioned above, the gases are fed continuously during the cycle through the adsorber. For example, with a typical set of timer adjustments, during the purge time as set by the oxygen timer all but a preselected amount of oxygen is removed from the adsorber and adsorbent. Then, after the purge period the gases which include the remaining oxygen and are low in carbon dioxide are transferred from the adsorber to the storage chamber. This usually takes place during operation of the carbon dioxide timber. However, if the time period of the carbon dioxide timer is sufficiently small, transfer of oxygen from the adsorber would take place during operation of the carbon dioxide timer and during a portion of the operation of the cycle timer. Then, nally, carbon dioxide rich gas is supplied to the chamber for a preselected time period as determined by the period of operation of the carbon dioxide timer because during the latter portion of the cycle the adsorbent is substantially saturated with carbon dioxide and carbon dioxide rich gases then pass to the chamber. The total concentration of the carbon dioxide in the chamber therefore is made up of the carbon dioxide in the carbon dioxide poor gas and the carbon dioxide rich gas supplied as described.
The adsorber also removes gases in addition to carbon dioxide that may be detrimental to the stored products and are thus undesired third uids. For example, it has been discovered that unsaturated hydrocarbon gases and especially ethylene are detrimental to some stored animal and vegetable materials and are especially detrimental to stored bananas. These gases and particularly ethylene are adsorbed in the adsorber and therefore the adsorber also functions to remove these gases. Examples of other gases that are removed in this manner are saturated hydrocarbon gases such as methane, ethane and propane, and other oxides of carbon, particularly carbon monoxide. Thus, by making the cycle on each adsorber suiiiciently long, other gases such as those mentioned may also be removed so that the storage atmosphere in the storage chamber is substantially free of these gases.
The system As shown in FIGURE 1 there is provided a catalytic burner v that is supplied with a hydrocarbon fuel gas by way of a line 11 and pressurized air by means of a line 12 from a blower 13. The gas from the line 11 and air from the line 12 mix in the line 12 just before it enters the burner with the flow of gas being controlled by means of an adjustable orifice 14. In the air line 12 there is provided an air regulating valve 15 and a fixed orice 14a, while in the gas line 11 there is provided a gas regulator 16 that is connected by way of a line 17 to the air line 12. Attached to the gas regulator line 17 is a manually reset flash-back pressure switch 18 which is normally closed but which opens if there is flash-back in the burner 10 in order to shut off the system in a manner to be described hereinafter.
The gas regulator line 17 also contains an air pressure switch 19 which is normally open when the system is not operating but which is closed by air pressure when the amount of air provided by blower 13 is sufficient to support combustion of the burner 10, This prevents the system Operating when there is insufficient air pressure.
The gas and air mixture enters the burner 10 at the intake manifold 20 on the top of the burner and the products of combustion leave through the exhaust manifold 21. Located in the intake manifold 20 is a manually reset flash-back thermostat 22 above the catalytic portion of the burner 10 that is normally closed but is opened by any series of flash-back burning within the manifold 20. This thermostat switch 22 is an added safety device functioning in combination with the more remote flashback pressure switch 18.
Ignition of the gases within the burner 10` is accomplished by means of a spark plug 23 in the exhaust manifold 21. This exhaust manifold is provided with a ame detection switch 24 which detects burning and closes the electrical circuit to the controls to be described hereinafter for proper operation of the apparatus.
The products of combustion from the burner 10 containing oxygen, carbon dioxide and inert gases from the air flow through an exhaust line 25 to a water cooled condenser 26 where condensible vapors are removed from the exhaust. The condenser contains a flame arrester 27 to prevent any burning past this point within the generator. y
For cooling purposes there is provided a water inlet line 28 leading to the top plenum 29 and then to coils (not shown) within the condenser 26. From here the water ows through a line 30 to the top of the burner 10. Water ows through this top of the burner from one portion to another through a jumper tube 31 and from the top of the burner to the bottom thereof through a jumper water line 32. Water flows through this bottom of the burner 10 by way of another jumper line 33 and flows from the burner by way of an outlet line 34.
In the exhaust water line 34 there is provided a strainer 35 for straining out any solid particles and from here the outlet water ows through a chamber 36 in which is contained a sensing bulb 37 for a modulating water valve 38. A water line 39 is provided leading from the chamber 36 by way of a ow control valve 40. With this arrangement flow of exhaust water from the burner 10 is controlled by the temperature of the water in the manner explained in the above-mentioned copending application Ser. No. 213,398. From this control apparatus the water exhausts through an exhaust line 41.
Condensate from the condenser 26 ows from the condenser by way of a lower plenum 42 and a condensate disposal line 43,
From the condenser 26 a gas conduit 44 leads to a valve 45 having a damper 46 therein operated by a motor 47. From this valve 45 a conduit 48 leads to a conduit 49 which exhausts to atmosphere.
From the valve 45 a conduit 50 leads to conduit 55, one end of which leads to a valve 56 and the other end leads to a valve 57. The valve 56 has a damper 58 operated by a motor 59 while the valve 57 has a similar damper 60 operated by a motor 61.
A valve communicates by =way of a conduit 68 with a storage chamber identified diagrammatically in FIG- URE 1 at 69. The valve 65 also communicates by way of the conduit with the previously mentioned conduit 49.
Valve 56 is located at the bottom o-f adsorber 70 which is one of a pair of adsorbers or sorption means with the other being identified at 7.1. Valve 56 communicates with the bottom of the adsorber 70 through :a conduit 72 While valve 57 is provided with a similar conduit 73. Valve 56 also communicates by way of a conduit 74 with the exhaust conduit 49.
At the top of the adsorber 70 there is provided a valve having a damper 76 operated by a motor 77. One side of this valve communicates with a conduit 64 while the second side communicates with a conduit 78` which is part of an air line leading from a second blower 79 operating as a source for oxygen. Both blowers 13 and 79 are operated by a common motor 80 and a conduit 81 leads from blower 79 to a valve 82 having a damper 83 operated by a motor 84. A conduit 63 intersects at one end a conduit 64 and connects at the other end to a valve 65. This valve like the others has a damper 66 operated by a motor 67.
Located between the blower 79 and the valve 82 is a normally open air pressure pulse switch 85 adapted to be momentarily closed by pressure pulses in the conduit 81.
The valve 82 communicates with conduit 78 and also with a valve 86 at the top of adsorber 71 by way of a conduit 87. The valve 86 is provided with =a damper 88 operated by a motor 89. Valve 86 communicates with the top of adsorber 71 through a conduit 90 and corresponding valve 75 is provided with a similar conduit 91.
Also in the system of FIGURE 1 as Well as certain other figures there is a gas valve 92 in the gas line 11 operated by :a solenoid 93. There are also control thermostats and switches including a fuel pressure switch 94 that is normally open when the system is not in operation but which is closed by the fuel pressure when the fuel supply is adequate for the proper operation of the system. This fuel pressure switch is illustrated in the circuit wiring diagram of FIGURE 2. There is also provided a cooling water thermostat 95 in the cooling water exit line 34 which is normally closed but which opens to break the electric circuit, as shown inl FIGURE 2, if the cooling water is excessively hot which would indicate improper operation of the burner, or inadequate water supply.
The burner is provided with an operation sensor 96 immediately above the burner which is normally open when the system is not operating but which is closed by the heat of the burner when the system is operating normally. In the electrical circuit, as shown in FIGURE 2, there is provided a manu-al ignition switch 97 which is normally closed whether or not the system is operating and is open only for interrupting the electrical circuit when such is desired as for servicing various parts thereof.
The dampers of all the valves in FIGURE 1 are shown in their de-energized (spring loaded) solid line positions. When the respective electric motor for each damper is energized, that damper then moves to the dotted line position, also shown in FIGURE 1. The electrical circuit timers and other operating controls for these various valv-es are described in detail hereinafter.
The adsorbers 70 and 71 are of the type disclosed in the above Thomas et al. application.
The electrical control circuit The control circuit for the embodiment of the invention disclosed in the drawings is shown in FIGURE 2 with the timers and adjacent portions of the circuit shown in greater detail in FIGURE 3.
The apparatus is supplied with power from two electric leads 139 and 140. A customary fuse 141 is provided as well as a double pole master line switch 142.
From one side of the switch 142 there is provided an electric line 143 to a relay 144. This relay is provided with a double pole double throw switch 145 having two poles 146 and 147 and four contacts 148, 149, 150 and 151. The two poles 146 and |147 are connected by a lead 152.
From the line 143 a line 153 is connected to an ignition control 154. This is a conventional ignition control system commonly used with oil or gas burners and is a readily available commercial unit. The control functions to connect terminal 1 to terminals 3 and 4, as indicated by the dotted lines on FIGURE 2, for a predetermined period of time that may be set on the control 154. Upon the expiration of this predetermined or preselected time, terminal 1 will automatically be disconnected from terminals 3 and 4 unless the flame detector switch 24 has closed to indicate the presence of ii-ame in the burner.
If the iiame switch 24 closes before the expiration of the predetermined time, terminal 1 will be disconnected from terminal 4 but remains connected to terminal 3.
In line 153 are the various switches previously described which are used to insure that the apparatus of this invention. is functioning properly. Thus, these switches which are connected in series include the air pressure switch 119 which closes when there is a proper amount of air for efficient combustion, ignition switch 97 which is normally closed at all times and is customarily only opened when it is desired to remove the control 154 from the circuit as for servicing or the like. Other switches in this series are the manually reset flash-back pressure switch 18 which is a safety switch and which is normally closed unless there has been a ash-back of flame in the burner, the manually reset flash-back thermostat 22 which is normally closed and located on the intake manifold monitors high temperature caused by ashback burning within manifold 20, and a fuel pressure switch 94 that is normally open but is closed when the gas in the system is at sufficient pressure for efficient burning. Finally in this series of switches is the cooling water thermostat switch 95 which is normally closed but opens if the cooling water from the burner 10 is excessively hot. The location of these various switches in the system are shown in the other views and have been described.
Typical operating conditions for the apparatus of this invention involve combustion within the burner '10 at a temperature below about 2000 F. in order to prevent formation of harmful oxides of nitrogen. The power supply is a conventional volt 60 cycle alternating current supply and the settings for the various thermostats and pressure switches in one embodiment may be as 'follows: The safety thermostat 173, normally closed, is set to open at F., the cooling water thermostat 95, normally closed, is set to open at 190 F., the air pressure switch 19 is arranged to close at a pressure of about 2.5 inches of water, the flash-back pressure switch 18 is set to open fat a pressure of about 5.7 inches of water, the fuel pressure switch 94 closes at a pressure of about 4.0 inches of water, the flash-back thermostat 22 is normally closed but opens at about 325 F. |which has been found sufiicient to show excessive Hash-back, the operation sensor 96 closes at about 175 F. and the flame detection switch 24 is normally open but closes when the temperature of the gases in the exhaust manifold 21 are about 375 F. These values, of course, are only given for one embodiment of the invention and maybe varied.
Terminal 4 on the control 154 is connected to a transformer which loperates the spark plug igniter 23. The other side of the transformer 155 is connected by a line 156 to a line 157 which is in turn connected to the Second pole 158 of the switch 142.
Terminal 3 of control 154 is connected by line 159 to the operation sensor thermostat 96 previously described. Between line 159 and line 156 is connected the solenoid 93 for the gas valve 92, both previously described.
The other side of the operation sensor 96 is connected to an operating solenoid 160 for the relay switch 145 with the mechanical connection of the solenoid 160 to the switch poles 146 and 147 being indicated by the dotted line 161.
The other side of the solenoid 160 is connected by line 162 to line 156 and also to terminal 2 of control 154.
Terminal 148 of the four terminals on the relay 144 is connected to line 163 which is connected to line 164 and to a light 166 whose other side is connected to the line 156.
Another terminal 149 on the relay 144 is connected by a line 167 to an indicator light 168 Whose other side is also connected to the line 156.
The third relay terminal 150 is connected by line 169 to a line 170, while the fourth terminal 151 of the relay is connected by a line 171 to motor 47 by bypass valve 45.
Between the lines 143 and 156 of opposite sides of the switch 142 there extends a line 172 in which is located the blower motor 80 for operating the two blowers 13 and 79. Also in the line 172 is a manually reset, normally closed, safety thermostat 173 that is located at the gas outlet of the condenser 26 that opens to stop the blower 80 if the temperature in the condenser plenum 29 becomes too great.
The electrical system also includes a cycle timer 174 having an operating motor 175 that operates a cam 176 to move a switch arm 177 between a pair of contacts 178 and 179. One side of the motor 175 is connected to a line 180 while the other side is connected to the line 157. Each `f the valve motors 47, 59, 77, 84, 61, 89 and 67 iS connected to this line 157 which is connected to line 140 through pole 158 of switch 142.
As shown in FIGURE 2 valve motors 59, 77 and 84- are connected in parallel with each other and to contact 178 of the cycle timer while valve motors 61 and 89 are in parallel with each other an connected to the other timer contact 179. Valve motor 67 is connected to a line 182.
The movable switch arm 177 on the cycle timer is connected by the previously mentioned line 164 to line 163 from the relay 144.
As is shown in greater detail in FIGURE 3, the electrical control system includes two adjustable timers, one of which is a carbon dioxide timer 183 and the other is an oxygen timer 184. These timers are manually adjustable to operate for preselected times and are capable of resetting automatically at the end of the preselected time period. They are commercially available and are known as Cycl-Flex timers. The only difference in construction between the two timers is the length `of time cycle. Timer 184 has a time cycle which may be varied from 0 to 120 seconds. Timer 183 has a time cycle which may be varied from 0 to 30 minutes. Timer 83 does not utilize a switch (not shown) comparable to switch 198 of timer 184.
Timer 184 includes a first energizable means shown as a solenoid 185 and a second energizable means shown as a motor 186. This timer also includes a first electrical circuit 187 extending to a first switch 188 with this first switch 188 being connected by way of line 170 to a switch 189 in the other or carbon dioxide timer 183. This timer 183 contains a first energizable means in the form of another solenoid 190 similar to the solenoid 185 and a second energizable means shown as a motor 191 similar to the motor 186. The timer 183 also contains an electrical circuit 192 that is similar to the electrical circuit in the oxygen timer.
In addition to the switch 188 the oxygen timer 184 contains a normally closed switch 193 with the two switches being operated by the solenoid 185 as indicated by the dotted line 194. When solenoid 185 is not energized, the switch 188 is in the open postiion shown while switch 193 engages contact 19S. When the solenoid 185 is energized the two switches are moved down from their solid positions to their dotted line positions as shown in FIG URE 3 to engage contacts 196 and 197, respectively.
Oxygen timer 184 also contains a switch 198 that is operated by the motor 186 as indicated by the dotted line 199 and a switch 200 that is also operated by the motor 186 as indicated by the dotted line 201.
Carbon dioxide timer 183 also contains a switch 202 similar to the switch 193 of the oxygen timer and a switch 203 similar to the switch 200 of the oxygen timer. Switches 189 and 202 are operated by the solenoid 190, as indicated by the dotted line 204, while switch 203 is operated by the motor 191, as indicated by the dotted line 205. When the solenoid 190 is de-energized switch 202 engages contact 206 and :when solenoid 190 is energized switch 202 diseI1 gages contact 206 and switch 189 engages contact 208.
As shown at the top of FIGURE 3 switch 202 is connected to line 170 while contact 206 is connected to line 180 and switch 189 is connected to line 170. Contact 208 is a part of the circuit 192 and the motor 191 is in its own circuit 209, one side of which is connected to line 157 and the other side of which is connected to contact 210 of switch 203 and to a line 211.
As is shown in the lower portion of FIGURE 3, the oxygen timer 184 switch 193 is connected by line 212 to line 170. Contact 195 is connected to line 182 while contact 197 is connected by line 213 to switch 198. Also in timer 184 switch 188 is connected to line 170 by line 214 while contact 196 is connected by line 215 to line 187 which in turn is connected to -switch 200. The motor 186 is in its own line 216, one end of which is connected to line 157 by way of a line 217 and the other end of which is connected to a contact 218 of switch 200. Contact 218 is also connected by lines 219 and 220 to the air pressure pulse switch previously described. The line 220 is connected to one contact 221 of the switch 85 and is provided with a movable arm 222 that is normally out of engagement with contact 221 but which is moved into momentary engagement by surges of air pressure within the conduit 81 from the blower 79.
Operation With the gas supply through the line 11 and the air supply from the blower 13 both -being of sufficient pressure for proper operation of the burner and with all of the precautionary safety switches including the air pressure switch 19, ignition switch 97, flash-back pressure switch 18, flash-back thermostat 22, gas pressure switch 94 and the cooling water temperature thermostat 95 functioning properly, indicating proper operating conditions for the burner, the circuit from line 143 to terminal 1 of the control 154 will be completed. This causes current t0 flow into the transformer 155 by way of terminals 1 and 4 of the control 154 to energize the spark plug 23 and ignite the fuel in the catalytic burner 10 which is the source means for gases containing carbon dioxide. Current flowing from terminal 3 of the control 154 energizes the gas valve solenoid 93 to open the gas valve 92. Current flowing from line 143 to the double pole double throw relay switch 145 and through switch arm 147 to line 167 energizes the indicator light 168 to show that the apparatus is functioning. Similarly, current owing from line 143 through pole 146 of the switch energizes valve motor 47 to move the damper 46 of bypass valve 45 (fourth valve) to its dotted line position as shown in FIGURE 1 so that the initial products of combustion will pass into line 48 and from there to the ambient atmosphere through line 49. This is a precautionary measure, as often the initial products of combustion are contaminated by unburned gases and are therefore vented during this initial period.
As mentioned earlier, the control 154 connects terminal 1 to terminals 3 and 4, as illustrated by the dotted lines in FIGURE 2, for a predetermined period of time. Upon the expiration of this predetermined period, which is usually about 70 seconds, terminal 1 will automatically be disconnected from terminals 3 and 4 unless flame detector switch 24 has closed. If switch 24 closes, terminal 1 is disconnected from terminal 4 but remains connected to terminal 3 to keep the gas valve open. This automatic disengagement of terminals 3 and 4, if switch 24 is not closed by flame in the burner, is a safety device in order to shut oii both the sparking of the igniter plug 23 and the gas supply as under these conditions the burner would not be operating properly.
If the burner continues to operate properly for approximately 10 minutes, the operation sensor 96 is heated suficiently and closes to energize the solenoid of relay 144 and move the relay switch poles 147 and 146 out of engagement with contacts 149 and 151 and into engagement with contacts 148 and 150. This breaks the circuit to the bypass valve motor 47 so that the products of combustion are no longer vented to the atmosphere. The engagement of pole 146 with contact 150 energizes the cycle 9 timer motor 175 by way of switch 202 of the carbon `dioxide timer 183 as `shown in FIGURE 3. The electric energy to switch 202 is supplied by line 169.
The engagement of switch pole 147 with contact 148 operates through switch 177 of the cycle timer to energize valve motors 59 (first valve), 77 (second valve) and 84 (fifth valve) and moves dam-pers 58, 83 and 76 to their dotted line positions which serves to place adsorber 70 in the circuit from the condenser 26. The energizing of motor 84 also moves damper 83 to its dotted line position so that air from the blower 79 then flows down through the adsorber 71 by way of line 81, valve 82 (fifth valve), line 87 and valve 86 (seventh valve) to rejuvenate the adsorber 71 by removing previously adsorbed carbon dioxide. The air `then flows out the bottom of adsorber 71 and through valve 57 (sixth valve) and line 49 to the ambient atmosphere.
The moving of damper 83 to its dotted line position, as described above, causes a momentary air pulse in line 81 to operate switch 85 and move the arm 222 of switch 85 into momentary engagement with contact 221 (FIG- URE 3).
The engagement of the arrn 222 with contact 221 in the impulse switch 85 energizes solenoid 185 from power supplied by way of lines 220 and 170 and -pole 146 of switch 145 which, as described above, is still in engagement with the Contact 150. This arrangement means that power is supplied to line 170 from line 143 and connecting line 169.
The momentary closing of `switch 222 energizes solenoid 185 and causes it to move switches 188 (tirst switch) and 193 (fourth switch) of oxygen timer 184 downwardly. This means that switch 188 engages contact 196 and switch 193 engages contact 197.
Because the bypass valve motor 47 is out of the circuit in the manner previously described, co-mbustion products now flow from the condenser 26 through line 44, valve 45 (fourth valve), line 50, line 55 and open valve 56 (rst valve) to the adsorber bed 70 for flow upwardly through the adsorber. The gases then flow through the open valve 75 (second valve) into line 64, line 63 (first conduit), valve 65 (third valve) and line 70 (second conduit) to exhaust line 49 which exhausts to the atmosphere.
This upward flow of burner gases through adsorber 70 proceeds for a preselected time that was set on the oxygen timer 184. As the adsorber 70 had been previously flooded with air in a previous cycle, much as adsorber 71 is now being flooded with air from blower 79 in the manner previously described, by exhausting a portion of the air and adsorbed oxygen present in adsorber 70` to the ambient atmosphere for a preselected time as determined by the oxygen timer 184, all but a preselected amount of air and adsorbed oxygen is removed from the adsorber. In other words, the combustion products purge air and adsorbed oxygen from the adsorberuntil the preselected desired amount remains which will be determined by the time set on the oxygen timer 184. One example of this purge time is indicated at 100 on FIGURE 5, to be discussed in detail hereinafter. At a later stage, to be described hereinafter, this remaining entrapped air and adsorbed oxygen which is, of course, made up of approximately 21% oxygen is transferred from the adsorber into the storage chamber 69. The adsorber functions both as a holding means for storing oxygen and as a means for retaining carbon dioxide.
As the oxygen timer 184 has in the above manner provided for the preselected amount of oxygen, with this being retained in the adsorber 70 for later use, the carbon dioxide timer now takes over to control the amount of carbon dioxide introduced into the storage chamber 69.
At the end of the preselected time, as set on the oxygen timer 184 in the manner described above, the motor 186` of the oxygen timer pulses switch 198 (third switch) down to engage the bottom contact 223. As switch arm 193 is still in engagement with .contact 197, this causes current to flow from line 170 through line 212, switch 193, contact 197, line 213, switch 198, contact 223 and line 211 into solenoid coil 190 (rst energizable means) of the carbon dioxide timer 183. It also causes current to ow through motor 191 (second energizable means) of the carbon dioxide timer by way of the motor circuit 209. The other side of the current supply is provided by the line 157. This energizing of solenoid 190 moves switches 189 (first switch) and 202 (second switch) down to engage contact 208 and disengage Contact 206. The energizing of the solenoid 190 and motor 191 starts the operation of the carbon dioxide timer 183. This de-energizes cycle timer motor 175 to stop the cycle timer while the carbon dioxide timer is operating since switch arm 202 breaks engagement with contact 206. During this period the adsorber 71 is still being reactivated with air blown through it from blower 79, as described above.
The carbon dioxide timer 183 continues to operate 'by reason of the moving down of switch 189, as described above. Immediately with the closing of switch 189, switch 200 (second switch) of the oxygen timer 184 is momentarily opened by motor 186 (second energizable means) through its connection therewith, as indicated at 201, and this breaks the circuit to the holding solenoid 185 (rst energizable means) thereby permitting switches 193 and 188 of the oxygen timer 184 to return to their up position as shown in FIGURE 3. This results in valve motor 67 then being energized by power supplied from line 170 by way of line 212, switch arm 193, contact 195 and line 182 to the motor 67. The energizing of motor 67 moves valve damper 66 to its dotted line position as `shown in FIGURE 1. With valve motors 59, 77, 84 and 67 now energized, gases rich in carbon dioxide are supplied from the condenser 26 to adsorber 70 `by way of pipes 44, and 55 and valves 45 and 56. Then the gases pass upwardly through the adsorber 70 where carbon dioxide is removed and carbon dioxide poor gases tlow into chamber 69 by way of lines 64, 63 and 68 and valves 75 and 65. This continues for a predetermined time, indicated at 101 on FIGURE 5, as set on carbon dioxide timer 183. The passage of these gases through the adsorber 70 not only removes carbon dioxide from the gases, with the carbon dioxide being adsorbed by the adsorber, but also carries the previously predetermined amount of oxygen that had 4been held all this time in adsorber 70 into the storage chamber along with the Iabove carbon dioxide free gases.
During this period, as previously mentioned, timer Y motor 175 is de-energized. This condition of supplying carbon dioxide poor gases and oxygen to the storage chamber continues for the preselected time set on the carbon dioxide timer 183. At the end of the preselected time, interval switch 203 of the carbon dioxide timer is pulsed open by timer motor 191 to open the circuit to the solenoid holding coil 190. This stops the operation of the carbon dioxide timer and it automatically resets itself to zero in preparation for later operation during the next cycle.
With the de-energizing of solenoid 190 switches 189 and 202 return to their solid line positions, as shown in FIGURE 3, with switch 202 moving into engagement with contact 206. This leaves valve motors 59, 77, 84 and 67 energized. At the same time, the cycle timer motor is energized by way of line 180, contact 206 and switch 202 in the carbon dioxide timer 193, line 169, contact 150, pole 146 and line 143. With this arrangement the combustion gases continue to pass from the condenser 26 through line 44, valve 45, line 50, line 55, valve 56, adsorber 70, valve 75, line 63, valve 65 and line 68 into the storage chamber 69 for the remaining time on the cycle timer 174, as indicated at 102 in FIGURE 5. As the adsorber `becomes saturated with carbon dioxide gases, as explained hereinafter, this provides carbon dioxide rich gases to the storage chamber 69 during the latter part of the cycle.
A The length of time that the gases are passed through the adsorber 70 in this manner is controlled by the cycle timer 174 which operates for a preset, fixed time. At the end of the preset time on the cycle timer 174, the cam 176 moves the switch arm 177 to the right, as shown in FIGURE 2, to disengage contact 178 and engage contact 179.
The moving of the cycle timer arm 177 in the manner previously described starts a new cycle of operation but using adsorber 71 in this cycle instead of adsorber 70.
The engaging of cycle timer arm 177 with contact 179 de-energizes valve motors 59, 77 and 84 and energizes valve motors 61 and 89. This energizing of motors 61 and 89 moves dampers 60 and 88, respectively, to their dotted line positions. The de-energizing of motor 84 permits damper 83 to return to its solid line position and the dampers 58 and 76 are similarly permitted to return their solid line position. This means that air from the blower 79 is now directed by way of line 81, valve 82, line 78 and valve 77 down through the adsorber 70 and through valve 56 and line 74 into the exhaust line 49 which exhausts to ambient atmosphere. This air iiow downwardly through the adsorber 70 serves to reactivate the adsorber by removing adsorbed carbon dioxide and to charge it again with air (oxygen).
The de-energizing of valve motor 84, as previously described, and the resulting movement of the damper to its solid line position, as shown in FIGURE l, again pulses air switch 85 for momentary contact of its arm 222 with the contact 221 so that the whole cycle begins over again, as previously described, except now adsorber 71 is in the system while the adsorber 70 is 'being reactivated, and recharged, with air.
The catalytic combustion provided by the apparatus of this invention together with cooling of the catalytic bed permits control of the temperature of combustion within a practical range of about l200-2000 F. Under these conditions the products of com'bustion have no measurable amounts of oxides of nitrogen.
In a preferred apparatus the air that is provided by the blower to the burner is preferably in about excess over that required for complete combustion of the fuel.
'In practical embodiments of the invention the percentage of oxygen in the atmosphere supplied to the storage chamber is between l and by Ivolume. In most instances, the amount of carbon dioxide in this atmosphere is preferably between about l and by volume.
The catalyst used in the burner of this apparatus is of the type previously described in Bedrosian et al. Patent 3,102,778, also assigned to the same assignee as the present application. Thus, a typical catalyst is a chromealumina catalyst containing chromic oxide in the form of 1/e inch extruded pellets.
As pointed out earlier, the amount of carbon dioxide supplied to the storage chamber and the amount of oxygen are controlled by the timers 183 and 184. The relationship of the variable controls to supply a desired concentration of carbon dioxide and a desired concentration of oxygen in the storage chamber is illustrated in FIGURE 4 for a typical embodiment.
In FIGURE 4 the abscissa of the graph shown gives the percentage of oxygen from 04.0%. The ordinate gives the amount of carbon dioxide from 0-l3.0%. The generally vertical slope lines 103 which unite at a peak 104, and marked 0-1.40, are the purge times given in minutes during which the burner gases pass through the adsorber to remove or purge the adsorber of air and adsorbed oxygen except that required to provide the preselected amount of oxygen in the adsorber for later trans- `fer to the storage chamber. The generally `horizontal (and downwardly sloping from the left to the right) lines 105 represent in minutes the time during which the carbon dioxide timer operates, and the cycle timer operation is interrupted. As shown, this time varies from 0-30 minutes. The operation of the carbon dioxide timer effectively increases or varies the total cycle period to provide a preselected amount of carbon dioxide rich gases to the storage chamber.
The graph of FIGURE 4 is of course accurate for one embodiment of the invention, namely a generator that burns propane, in which the exhaust gases contain 1.0% oxygen and 12.2% carbon dioxide. If a diierent type burner or generator were used, the graph of course would have different values.
With this particular embodiment,assume that it is desired to provide 4% carbon dioxide and 2% -oxygen to the storage chamber. The point of the graph for these conditions would be indicated by the point 106. Under these conditions, the carbon dioxide timer would be operated for 1.85 minutes, as indicated on the right-hand scale of the graph. Thus, as can be seen, the point 106 is this distance above the line for 1.5 minutes and below the line for 2.0 minutes.
The oxygen timer which governs the period in which the excess oxygen is purged from the adsorber would be set for 0.75 minute, as the point 106 is this proportional distance between the time lines 0.67 and 0.83 as shown at the bottom of the graph.
The operation of the system when the carbon dioxide timer and oxygen timer were thusly set is indicated on the FIGURE 5 graph.
On the FIGURE 5 graph the abscissa is in minutes from 0-14 minutes and indicates the total amount of cycle time available depending on the carbon dioxide timer setting. This should not be confused with the amount of time preset on the cycle timer because, as indicated above, the cycle timer does not operate during the period when the carbon dioxide timer operates. The total cycle time is the sum of the fixed time preset on the cycle timer and the variable time as preselected on the carbon dioxide timer. The ordinate of the FIGURE 5 graph is in percent from 0-21 and is used both for the percentage of oxygen and the percentage of carbon dioxide in the eluent gases passing from the adsorber.
Under the typical conditions and specific embodiment of the generator of FIGURE 5, the oxygen timer as mentioned is set for 0.75 minute to supply the 2% oxygen to the chamber. During this initial period, as indicated at on FIGURE 5, the excess oxygen is purged from the adsorber as by forcing the generator gases through the adsorber and then to the atmosphere. The cycle timer is running concurrently for the initial part of its fixed time period which in this embodiment is 6 minutes.
Then, as indicated by the line 101 on FIGURE 5, the carbon dioxide timer runs Ifor an additional 1.85 minutes to provide the desired 4% carbon dioxide. During this period, as previously explained, the cycle timer is interrupted so that its remaining 5.25 minutes of the 6 minute cycle (6 minutes minus 0.75 minute) is not being used. Then, at the end of the preset 1.85 minutes on the carbon dioxide timer, this timer stops and the cycle timer resumes for its remaining 5.25 minutes, as indicated by the line 102. At the end of this time the cycle timer switches to a new cycle, as indicated by the vertical line 107, during which the previously regenerated adsorber is now placed in the system and the saturated adsorber is regenerated in the manner described above.
The curve on the graph of FIGURE 5 indicated at 108 shows the percentage of oxygen at the exit 91 or 90 of the adsorber 70 or 71. The horizontal line 109 is used to indicate the amount of oxygen in the air used to regenerate the adsorber 70 prior to the beginning of this cycle. As shown by the line 108 the initial oxygen content of the gases coming from the adsorber at the beginning of the purge time is 21%. The oxygen content drops rapidly for the purge time of 0.75 minute and then drops even more rapidly in the irst approximately one and one-half minutes to an yoxygen content of about 1%. For the remaining period of the cycle the oxygen content at the exit of the adsorber falls only very slightly below this 1% value. This line 108 shows that the -oxygen remaining in the adsorber is transferred very rapidly from the adsorber into the storage chamber or receiver.
The curve 110 on the FIGURE 5 graph indicates the percentage of carbon dioxide from the adsorber 70. As is shown here, when the adsorber is fresh, as at the beginning of the cycle, the carbon dioxide content of these gases is extremely small, being only approximately 0.25%. Then, at the end of several minutes, in this embodiment about minutes, the carbon dioxide content of the gases from the adsorber begins to rise rapidly. This is because the adsorbent is becoming saturated with carbon dioxide. The maximum amount of carbon dioxide in the gases from the adsorber is arbitrarily set at a low value, indicated by the point 111 on the curve line 110, before the gases can be indicated as carbon dioxide rich. This point 111 which occurs Ibetween 5% and 51/2 lminutes after the system is in operation will terminate the 1.85 minutes indicated at 101 during which carbon dioxide poor gases are supplied to the chamber.
The line 110 shows that during the 5.25 minutes remaining in the cycle, as indicated by the line 102, the carbon dioxide content of the gases from the adsorber rises quite rapidly from the break-through point 111. By the time the cycle has terminated, as indicated by the -line 107, and the point 112 on the carbon dioxide curve 110 has been reached, considerable carbon dioxide poor gases have been supplied to the receiver or storage chamber. In fact, the point 112 is only slightly below the 12.2% carbon dioxide line 113 which is the carbon dioxide content of the gases coming directly from the generator.
In the above example, the remaining cycle time, here 5.25 minutes, is sufliciently long for the adsorber to adsorb and -remove the earlier mentioned undesirable gases, and'particularly ethylene, which might prove harmful to the stored materials.
Having described our invention as related to the embodiment shown in the accompanying drawings, it is our intention that the invention be not limited by any of the details 'of description, unless otherwise specified, but rather Ibe construed broadly within its spirit and scope as set out in the accompanying claims.
The embodiment of the invention in which an exclusive property or privilege is claimed is defined as follows:
1. Apparatus for supplying to a receiver a mixture of a first uid and a second fluid in predetermined amounts, comprising: source means lfor the first fluid; source means for the second iiuid; iiuid passage means leading to said receiver; holding means in said passage means for retaining a predetermined maximum amount of said first iiuid and for storing said second iiuid; means for introducing said second iiuid from its source means into said holding means for storage therein; and means for flowing said iirst uid from its source means through said holding means to said receiver in an amount in excess of said maximum amount to (l) supply said excess amount of iirst'fluid to said receiver and (2) simultaneously transfer said stored second iiuid to said receiver.
2. The apparatus of claim 1 wherein one of said fluids also contains an undesired third iiuid and said holding means comprises means for retaining said third fluid.
3. The apparatus of claim 1 wherein said means for introducing said second fluid from its source means into said holding means for storage therein supplies said second Huid in an amount in excess of said predetermined amount of second liu-id, and there are provided variable means for removing said predetermined amount.
4. The apparatus of claim 3 wherein one of said fluids also contains an undesired third -uid and said holding means comprises means for retaining substantially all said third iiuid.
S. The apparatus of claim 1 wherein s-aid iirst uid source means comprises a source for a uid mix containing said first uid, said means for flowing said first uid comprises means for flowing said fluid mix from its source means through said holding means to said receiver for -a variable predetermined time to 1) transfer said second fluid to said receiver and (2) provide iiuid mix relatively poor in said first fluid to said receiver in an amount dependent on said variable time, and there are provided means for flowing said fluid mix from its source means to said receiver for a second variable time to provide fluid mix relatively rich in tirst fluid after said holding means has retained said maximum amount, the total of said uid mix relatively poor Iin iirst uid and the mix relatively rich in tirst uid substantially constituting said predetermined amount of iirst tiuid.
6. The apparatus of claim S wherein one of said iiuids contains an undesired third fluid and said holding means comprises means for retaining substantially all said third fluid.
7. The apparatus of claim 6 wherein said fluid mix is capable of removing second fluid from said holding means when said iiuix mix is passed therethrough, and said second fluid is capable of removing said first iiuid from said holding means when said second iiuid is passed therethrough, but with said third tiuid being retained in said holding means, and there are provided tiuid disposal means, means for owing said second fluid from its source means through said holding means to said disposal means to remove any irst fluid from said holding means and for storing second uid in said holding means, means for fiowing said fluid mix from its source means through said holding means to said disposal means for a predetermined time to remove a predetermined fractional amount of second uid from said holding means, means for iiowing said fluid mix from its source means through said holding means to said receiver for a second variable time to (1) transfer the remainder of said second fluid in the holding means to said receiver and (2) provide uid mix relatively poor in said iirst uid to said receiver in an amount dependent on said variable time, and means for flowing said uid mix from its source means to said receiver for a third variable time to provide fluid mix relatively rich in iirst fluid after said holding means has retained said maximum amount.
8. The apparatus of claim 7 wherein there is provided a cycle timer means for limiting the total of said iirSt variable time and said third variable time to a constant preselected numerical value.
9. The apparatus of claim 1 wherein said first tiuid source means comprises a source for a fluid mix containing said iirst fluid, and there are provided fluid disposal means and means for flowing said tiuid mix from its source means through said holding means to said disposal means for a predetermined time to remove a predetermined fractional amount of second fluid from said holding means.
10. The apparatus of claim 9 wherein one of said uids also contains an undesired third iiuid and said holding means comprises means for retaining substantially all said third fluid.
11. The apparatus of claim 9 wherein said means for flowing said fluid mix from its source means through said holding means to said receiver includes means for limiting the period of said flowing to a second variable time and said means for flowing said fluid mix from its source means to said receiver is for a third variable time.
12. The apparatus of claim 11 wherein there is provided a cycle timer means for limiting the total of said first variable time and said third variable time to a constant preselected numerical value.
13. The apparatus of claim 9 wherein said uid mix is ca-pable of removing said second fluid from said holding means when said uid mix is passed therethrough, and said second iiuid is capable of removing said first uid from said holding means when said second fluid is passed therethrough, there are provided iiuid disposal means, and
15 means for flowing said second fluid from lits source means through said holding means to said disposal means to remove any first fluid from said holding means and for storing second uid in said holding means.
14. The apparatus of claim 13 wherein said means for flowing said fluid mix from its source means through said holding means to said receiver includes means for limiting the period of said flowing to a second variable time, the total of said fluid mix relatively poor in irst iiuid and the mix relatively rich in first fluid substantially constituting said predetermined amount of first uid.
15. Apparatus for supplying to a storage chamber for animal and vegetable materials an atmosphere containing a mixture of carbon dioxide and oxygen, comprising: source means for a gas containing carbon dioxide; source means for a gas containing oxygen; fluid passage means leading to said chamber; sorpton means in said passage means for retaining a predetermined maximum amount of carbon dioxide and for storting said oxygen gas; means -for introducing a predetermined amount of oxygen gas from its source means to said sorpton means for storage therein; and means for directing said carbon dioxide gas from its source means through said sorpton means to said chamber in an amount in excess of said maximum amount to (1) supply said excess carbon dioxide to said chamber and (2) simultaneously transfer said stored oxygen from said sorpton means to said chamber.
16. The apparatus of claim 15 wherein said means for directing said carbon dioxide gas from its source means through said sorpton means to said chamber includes means for limiting the period of said directing to a second variable time to provide gas relatively rich `in carbon dioxide to said chamber after said sorpton means has retained said maximum amount, the total of said carbon dioxide rich gas and :said carbon dioxide poor gas substantially constituting the total of carbon dioxide in said chamber.
17. The apparatus of claim 16 wherein one of said gases contains an undesirable fluid, and said sorpton means comprises means for retaining said undesirable uid substantially in its entirely.
References Cited UNITED STATES PATENTS 2,9l8,l40 12/1959 Brooks 55-68 X 3,203,771 8/1965 Brown et al. 23--281 3,237,377 3/1966 Skarstrom 55-68 3,285,701 11/1966 Robertson 23-232 JOSEPH SCOVRONEK, Primary Examiner.
U.S. CI. X.R.
|Cited Patent||Filing date||Publication date||Applicant||Title|
|US2918140 *||Jun 20, 1958||Dec 22, 1959||Sun Oil Co||Treatment of gas mixtures|
|US3203771 *||Jul 30, 1962||Aug 31, 1965||Whirlpool Co||Apparatus for controlling carbon dioxide content of an atmosphere|
|US3237377 *||Apr 12, 1962||Mar 1, 1966||Exxon Research Engineering Co||Oxygen concentration process|
|US3285701 *||Jan 18, 1963||Nov 15, 1966||Sinclair Research Inc||Process and apparatus for separating and analyzing a fluid mixture|
|Citing Patent||Filing date||Publication date||Applicant||Title|
|US4303009 *||Mar 30, 1979||Dec 1, 1981||Samifi Babcock, S.P.A||Apparatus capable of operating both as nitrogen generator and carbon dioxide absorber, particularly for the preservation under controlled atmosphere of products, such as fruit and vegetable products|
|US5152966 *||Jun 22, 1989||Oct 6, 1992||Nicap, Inc.||Apparatus for producing a controlled atmosphere|
|US8551215 *||Jun 24, 2011||Oct 8, 2013||James C. Schaefer||System and method of operation for controlled atmosphere storage|
|US20120325086 *||Jun 24, 2011||Dec 27, 2012||Schaefer James C||System and method of operation for controlled atmosphere storage|
|U.S. Classification||422/116, 96/144, 422/40, 137/624.11, 422/223|
|International Classification||A23L3/3409, B01F3/00, B01F3/02, A23L3/34|
|Cooperative Classification||A23L3/34095, B01F3/026|
|European Classification||A23L3/3409B, B01F3/02P|