Abstract:
The invention is a portable, non-pressurized oxygen generation device. A first chamber holds an oxygen liberating chemical, and a catalyst from a second chamber begins the oxygen liberating reaction when the two chemicals mix. The chemicals are pre-measured, and oxygen generation can begin within seconds of activation.

Description:
PRIORITY  
       [0001]     This application claims the priority dates of the provisional applications entitled Weak Seal Oxygen Generation Flexible IV System filed by Anthony J. Senn, et al. on Jun. 9, 2003 with application Ser. No. 60/477,452, Instant Chemical Based Flexible Oxygen in a Non-Pressurized Flexible or Rigid Containment System filed by Bert K. Moore, et al. on Apr. 21, 2004 with application Ser. No. 60/564,539, and Oxygen Generation Unit filed by Steven Hatten, et al. on Apr. 1, 2004 with application Ser. No. 60/558,809, the disclosures of which are incorporated herein by reference. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     The present invention is generally related to portable oxygen producing devices, and more particularly to a self contained, non-pressurized, flexible portable oxygen system.  
         [0004]     2. Background Information  
         [0005]     There are a number of situations in which a source of oxygen would be an essential lifesaving tool. This could include a situation where a person is in a burning building and a supply of oxygen, even if only for a few minutes, would increase his or her chances of escape from the smoke filled building. This could apply to office workers, rescue personnel or police.  
         [0006]     Another situation in which emergency oxygen would be useful is in response to an emergency situation, such as an environment filled with poisonous gases. This could occur in a chemical plant from a rupture of a tank, or could occur on a battlefield from the use of chemical weapons. In such a case, having a quickly available supply of oxygen, which has been conveniently stored and has a long shelf life, would be a lifesaver. Other situations in which an emergency supply of oxygen would be useful would include use by pilots who may need to clear their head when flying at a higher elevation, first aid situations in which oxygen may need to be administered in the field before the person is picked up by oxygen equipped rescue personnel, at home where a person may wish to administer oxygen in response to shortness of breath, heart arrhythmia, heart attack, or stroke.  
         [0007]     The prior art includes many oxygen generation devices. Many of them involve a rigid canister in which oxygen gas is compressed, and from which it can be released for breathing. Other prior art oxygen generation systems are reaction vessels, in which chemicals of various types can be added in order to set up a reaction that generates oxygen. The problem with compressed oxygen is that these systems are expensive, heavy, and not practical for most people to have on hand. Devices based on a reaction vessel are impractical if the reaction vessel is bulky and hard to carry, and if the chemicals take any more than the absolute minimum of time and effort to add and mix for use. A person cannot hold their breath very long while preparing such a canister, measuring ingredients, and adding the ingredients. A reaction vessel which takes more than ten (10) seconds to access, activate, and begin receiving oxygen is not very effective. One which takes several minutes to access, activate, and begin receiving oxygen is not particularly practical in the situations that are described above.  
         [0008]     A portable emergency oxygen generation system needs to be small in size, have a long shelf life, be easy to activate, but which does not activate accidentally, and must generate breathable oxygen within a few seconds of activation. Anything that takes more than even five seconds is not effective in certain situations. None of the prior art oxygen generation devices has these features.  
         [0009]     Additional objects, advantages and novel features of the invention will be set forth in part in the description which follows and in part will become apparent to those skilled in the art upon examination of the following or may be learned by practice of the invention. The objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.  
       SUMMARY OF THE INVENTION  
       [0010]     These, and other objects are achieved in the oxygen generating system of the invention.  
         [0011]     One embodiment of the invention includes a reaction chamber that is partially filled with a first reaction material. The portable oxygen generation system further includes a second chamber that is adjacent to the first chamber. The second chamber includes a pre-measured volume of a second reaction material. The first and second reaction materials are selected so that oxygen is generated when the first and second reaction materials are mixed. The system includes an oxygen release tube that is positioned within the reaction chamber so as to be above the level of the first material. The reaction chamber, with the first reaction material that it encloses, is designed with the oxygen release tube so that the reaction chamber may be in any spatial orientation and the end of the oxygen release tube will be above the level of the first reaction material. An activation means is included that is configured to immediately activate oxygen generation by opening the second chamber to allow immediate mixing of the second material with the first material. This results in immediate and continuous oxygen production from the mixing of the two materials and their subsequent reactions. A delivery device is included that delivers oxygen from the reaction chamber to a user. The size of the reaction chamber and the volume of materials determine the duration of oxygen generation. Typical times for the device are about twenty minutes of oxygen generation. Longer oxygen generation can be achieved by using more of the first and second materials and a larger reaction vessel.  
         [0012]     One embodiment of the invention includes a reaction chamber that is a semi-rigid material. In this version of the device, the second chamber is a breakable ampule containing a quantity of the second reaction material. The ampule is supported in an ampule bracket within the reaction chamber. The activation means of this system is an ampule breaking device. The ampule breaking device is typically a plunger pin that may be spring loaded and fitted with a locking device for preventing unwanted activation. When the locking device is disengaged, the ampule may be broken by pressing down on the plunger, causing the ampule to be broken and allowing the contents of the ampule to mix freely with the contents of the reaction vessel. This system includes an oxygen release tube that extends from the reaction chamber wall to the approximate center of the wall. The oxygen release tube has a tube opening, and because the first material only partially fills the vessel, the tube opening remains above the level of the first material when the reaction vessel is in any orientation. The oxygen release tube is typically attached at one end to the reaction chamber wall and extends through the chamber wall, where a hose barb allows it to attach to delivery tubing. This design further includes an external carrying pouch, in which the oxygen generation system can be stored and transported where it is available for use. The action to generate oxygen is an exothermal one. The external carrying pouch thus serves the important function of isolating the user from the heat generated in the reaction.  
         [0013]     Another version of the oxygen generation system includes a reaction chamber that is a flexible pouch. One version of this design includes an external hard case that surrounds or partially surrounds the flexible pouch. The reaction chamber of the vessel is a chamber inside the flexible pouch. The second chamber is also a chamber within the flexible pouch, which is separated from the reaction chamber by a seal. Squeezing the flexible pouch may rupture the seal between these vessels. The semi-rigid outer container of this embodiment may have openings on the sides that allow the flexible container to be accessed for squeezing the bag to activate the oxygen generation reaction. In the version of the device that includes a flexible pouch, the oxygen release tube extends from a reaction chamber wall to the approximate center of the reaction vessel and because of the level of the first material in the reaction vessel, the tube opening of the oxygen release tube remains about the level of the first material when the reaction vessel is in an spatial orientation. The oxygen release tube may be a flexible tube that includes a float at the end that assists it in keeping it above the liquid of the reaction vessel. This version of the device would also preferably contain an outer containment pouch for holding the flexible bladder during use of the system.  
         [0014]     Another embodiment of the oxygen generating system of the invention is portable and includes a flexible bladder constructed of resilient material. The bladder is configured to define at least two chambers. Each chamber is separated from the other chambers by a separation membrane. The separation membrane is relatively weaker than the resilient material of the flexible bladder. Since the material of the separation membrane is relatively weaker, when sufficient pressure is applied to the flexible bladder, which transmits pressure to the separation membrane, the separation membrane ruptures. At that time, the materials in the chambers are allowed to pass between chambers and begin a reaction in which oxygen is generated. Thus, merely squeezing a flexible container by hand can start the reaction.  
         [0015]     Also included in the portable oxygen generation system of the invention is a delivery system that is configured to deliver the oxygen that is created within the flexible bladder, to a user.  
         [0016]     Typically, the delivery system of the device will include a conduit in the form of a plastic tube for delivering oxygen from the flexible bladder to the user. At one end of the conduit is located an oxygen delivery mask, which may be worn by the user for breathing oxygen. A nasal canula would also be a possible delivery device.  
         [0017]     The portable oxygen generation system of the invention functions as described above, but alternate embodiments may contain additional features. These can include a humidifying chamber. When oxygen is generated in the flexible bladder, it is part of an exothermic reaction and enters the conduit and the oxygen delivery mask in a fairly warm and dry state. An inline chamber in the conduit may be helpful to cool the oxygen before it reaches the delivery mask. It also has the effect of adding some humidity to the oxygen. If the humidifying chamber is structured for bubbling, observing bubbles passing through the humidifying chamber serves to assure the user that oxygen is being generated and passing through the conduit to the delivery mask.  
         [0018]     Another feature that is desirable in certain embodiments of the invention is to have a filter located inline between the user and the flexible bladder. This filter can serve as a check valve, and allow oxygen gas but not liquid from the flexible bladder pass into the delivery of the conduit and delivery mask. Such a check valve can be made of a hydrophobic material which allows air to pass, but does not allow water to pass. Certain types of hydrophobic filters are basically filter paper that is coated with Teflon, or a similar material. In filters such as these, liquid water absolutely does not pass through the filter. Other types of check valves would also perform this function, such as check valves for preventing liquid flow in a line.  
         [0019]     It may be further desirable to have a chemical filter inline in the conduit between the flexible bladder and the delivery mask. The flexible filter would be provided to absorb odors or product chemicals from the exothermic reaction. To achieve this purpose, the chemical filter could contain an activated charcoal unit through which the generated oxygen passes. Gasses other than oxygen would be absorbed and/or reacted by the activated charcoal, leaving only pure oxygen to pass to the user. A foam or fibrous portion of the filter would also be desirable.  
         [0020]     Another feature that may be utilized is an oxygen flow indicator. This would be an inline indicator, typically one that changes color, to indicate the flow of oxygen in the tube.  
         [0021]     Another feature of the oxygen generation system of the invention is an outer pouch. An outer pouch serves several functions, and can be quite important for the oxygen generation system. One function it serves is that it protects the flexible bladder from external injury, so that it is less likely to be ripped or torn. The outer pouch is also preferably liquid proof, and thus would serve as a containment vessel if the liquid in the flexible bladder leaked. Another function of the outer pouch is to act as a holder for the flexible bladder while the flexible bladder is generating oxygen. Many oxygen generation reactions are exothermic reactions that can produce a considerable amount of heat. Thus, it might be uncomfortable for a user to hold the flexible bladder while it is generating oxygen. The outer pouch serves the purpose of providing an insulating carrying case, which insulates the user from the heat generated during oxygen production. The outer pouch can include a shoulder strap, or a handle. It can also be provided with a hole through which the air line can pass, so that the outer pouch and the flexible bladder can be placed in an oxygen generation cabinet.  
         [0022]     Depending on the chemicals selected to produce oxygen in the oxygen generation system, the flexible bladder may be configured to have three chambers. Each of these chambers is separated from the others by a separation membrane. These separation membranes are made of a flexible sheet of material, which ruptures when a sufficient amount of pressure is applied to it.  
         [0023]     The purpose of the foregoing abstract is to enable the United States Patent and Trademark Office and the public generally, and especially the scientists, engineers, and practitioners in the art who are not familiar with patent or legal terms or phraseology, to determine quickly from a cursory inspection the nature and essence of the technical disclosure of the application. The abstract is neither intended to define the invention of the application, which is measured by the claims, nor is it intended to be limiting as to the scope of the invention in any way.  
         [0024]     A delivery device is configured for use with the flexible bladder. The delivery device is not attached to the bladder until use of the device is desired. As will be described later in detail the configuration of the delivery device and the connection of the delivery device to the flexible bladder can be varied according to the necessities and preferences of the potential users and customers.  
         [0025]     Once the flexible bladder of the present invention has been properly constructed and filled, it may be stored in a designated location or it may be assembled for use. In order to use this embodiment of the invention, the delivery device must be attached to the flexible bladder. Connection between the flexible bladder and the delivery device is typically performed by attaching a hose end of the delivery device to the flexible bladder. Rupturing the ampule or squeezing the flexible container bag will then allow the materials in the various chambers to mix together so as to allow the production of oxygen within the reaction chamber or flexible bladder bag.  
         [0026]     In storage, the various configurations of the device may be stored as a single unit. In a three-chamber design, a liquid chamber is filled with sterilized liquid so as to prevent bacterial contamination. The first compound may be sodium percarbonate, hydrogen peroxide, or a number of other oxygen generating chemicals. The second compound may be manganese powder, which is preferably reagent grade manganese dioxide. In the stored position, the contents of the first and second chambers are separated by the ampule wall or by the weak seal separations between the various chambers. When these chemicals are separated, no chemical reaction will take place, and the oxygen generation device can be simply stored. The exact formulation of the weak seal and flexible bladder walls can also be variously embodied. In some situations the weak wall may simply be a weakened seam, or aperture, which is configured to open and allow integration and mixing of the various chemicals within the device. In other embodiments the whole wall may be configured to allow leakage when pressure is applied to the device.  
         [0027]     In order to use the device of this embodiment, a delivery device may be attached to the rigid outer container or inserted into the flexible bladder by a medical spike-type apparatus that is hollowed to provide transport of material out of the liquid chamber. After the attachment is made, the device may be activated by breaking the ampule or squeezing the bladder. In one embodiment, when the device is squeezed, a quantity of liquid will travel through a check valve into a humidifier chamber. When a sufficient quantity of liquid has entered into this chamber to reach the liquid line, the tubing clamp below the liquid chamber is cut off to prevent further flow of material up into the delivery device. As liquid is displaced out of the liquid chamber into the humidifier chamber, it is replaced with air through the liquid chamber. Once this has occurred, the entire flexible bladder may then be squeezed.  
         [0028]     In the case of the bladder with chambers separated by weak seals, when the bladder is squeezed, the differences in volumes on the sides of the chambers and between the chambers create an uneven force along the walls. These weak seal walls will then rupture and fail when the chambers are pressed. When this occurs, a mixture of materials between the varying chambers exists, and as this takes place, oxygen is produced as the chemical reaction between the various items within the chambers occurs. Once the materials have been mixed, and oxygen begins to be formed, the oxygen can be exited from the flexible bladder and delivered through the device to a mask, nasal canula or other delivery system to an individual. This is done by opening the tubing clamp. When the tubing clamp is open, oxygen will flow through the conduit, past the check valve into the humidifier chamber. The presence of bubbles ascending to the liquid line within the humidifier chamber gives positive identification to the individual utilizing the device that oxygen is being produced and is passing through the chamber. The mixture of liquid with the oxygen also makes these things more palatable.  
         [0029]     Along the delivery device conduit may be located a hydrophobic filter chamber that allows the oxygen to pass through for use but prevents the passage of liquid through. This is a safety feature, which prevents unwanted aspiration of liquid from the material into the respiratory system of the individual utilizing the device. Another design to prevent liquid from entering the conduit is to utilize a liquid trap in which liquid entering with the oxygen is collected in a cup, and only gas passes out of the liquid trap.  
         [0030]     The present invention provides a dependable portable emergency oxygen system that can have an indefinite shelf life and provide immediate capabilities for oxygen production and use without the requirements of filling with liquid, filling with water, adding catalysts, or other things that may be required in other methods. The present invention can be variously modified to use in a variety of environments such as emergency medical situations, armed conflicts, field use by military and rescue personnel, home first aid, building and tank evacuation, mountain climbing, airplane flying, and other uses. In addition, because the devices are fully self-contained, they could be utilized as a backup in other activities where a respirator is used. Due to the fact that the device is made of non-compressed materials, they are much less bulky and less of an environmental and ecological hazard than those devices that use compressed gas in cylinders.  
         [0031]     In various embodiments, depending upon the requirements of the user, the rate of oxygen flow and production may be varied by the configuration of the chambers within the device or by the use of flow rate valves within the delivery device.  
         [0032]     One embodiment of the device utilizes the reaction of sodium percarbonate, which reacts with water in the presence of the manganese catalyst. Another embodiment utilizes hydrogen peroxide of approximately 7.5% in an aqueous solution, and a rare earth metal such as reagent manganese dioxide or any number of other known catalysts, or combinations thereof. The two are mixed together, starting an exothermic reaction, which liberates pure oxygen. The reaction is 2H2O2 (Aqueous solution)→(catalyst) 2H2O+O2. While this reaction is set forth as the preferred method of such a production it is to be distinctly understood that the invention is not limited thereto but may be variously embodied to meet the specific necessities of a user. Furthermore, while the present invention is described in the context of an oxygen producing device it is to be distinctly understood that the present invention may also be utilized in a variety of other types of gas production.  
         [0033]     In one embodiment, the bag would be built and sterilized and the components then filled in the appropriate chambers. The tubing assembly would be stored with the flexible bladder, but not attached to the bag. This would allow the oxygen system to be stored until the time of use. This provides a self-pressurizing oxygen delivery system that may be utilized in a variety of circumstances including on the battlefield or other areas where access to water is unavailable. The invention is intended to be a disposable unit, therefore eliminating the need for excess storage. In addition, because the device is collapsible after use, the amount of space and weight required to haul the device is significantly decreased.  
         [0034]     Still other objects and advantages of the present invention will become readily apparent to those skilled in this art from the following detailed description wherein I have shown and described only the preferred embodiment of the invention, simply by way of illustration of the best mode contemplated by carrying out my invention. As will be realized, the invention is capable of modification in various obvious respects all without departing from the invention. Accordingly, the drawings and description of the preferred embodiment are to be regarded as illustrative in nature, and not as restrictive in nature. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0035]      FIG. 1  is a perspective view of an embodiment of the present invention.  
         [0036]      FIG. 2  is a cross-sectional view of the embodiment shown in  FIG. 1 .  
         [0037]      FIG. 3  is a cross-sectional view of a filter element of the invention.  
         [0038]      FIG. 4  is a second embodiment of the present invention.  
         [0039]      FIG. 5  is a side view of a third embodiment of the present invention.  
         [0040]      FIGS. 6A-6D  shows the invention in use.  
         [0041]      FIG. 7  is a front view of an embodiment of the present invention.  
         [0042]      FIG. 8  is another embodiment of the present invention. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0043]     While the invention is susceptible of various modifications and alternative constructions, certain illustrated embodiments thereof have been shown in the drawings and will be described below in detail. It should be understood, however, that there is no intention to limit the invention to the specific form disclosed, but, on the contrary, the invention is to cover all modifications, alternative constructions, and equivalents falling within the spirit and scope of the invention as defined in the claims.  
         [0044]     Several preferred embodiments of the oxygen generation system of the invention are shown in the enclosed figures.  FIG. 1  is one preferred embodiment of the system. It includes a reaction chamber  12 , a delivery system that includes an air line clip  58 , a liquid trap  62 , a filter chamber  66 , conduit  50 , and an indicator chamber  60 . On the top of the reaction chamber  12  is located a device for breaking the ampule  32  and a locking device  36 . An ampule  26  is visible on the side of the reaction chamber  12  and internal components of the device are seen well in  FIG. 2 .  FIG. 2  is a cross-sectional view showing the interior of the reaction chamber  12 . Inside the reaction chamber  12  is a first reaction material  14 . There is also a second chamber  16 , which in this embodiment is a breakable ampule. Inside the ampule  26  is a second reaction material  18 . Above the ampule  26  is located a plunger pin  30 , which is used to break the breakable ampule. A locking device  36  is located below the plunger button  80 . A hose barb  82  penetrates the wall of the reaction chamber  12  and extends into the reaction chamber as an oxygen release tube  20 . The indicator chamber  60  contains a chemical that indicates when oxygen is flowing through the tube.  
         [0045]     This oxygen generation unit can take a number of configurations and sizes, but a functional size for the reaction chamber has been found to be about one liter. With a one-liter volume, 300 to 350 mil of first reaction material  14  has been found to be appropriate. Seven to eight grams of the second reaction material  18  is appropriate for these volumes. When the second reaction material  18  is mixed with the first reaction material  14 , a reaction takes place in which O 2  is generated. As O 2  is generated, it pressurizes the reaction chamber above the liquid level and exits the reaction chamber through the oxygen release tube  20  and out the hose barb. It then passes through the air line clip  58 , the liquid trap  62 , the filter chamber  66 , and the indicator chamber  60 . It would also be connected to a face mask or nasal canula, which is not shown in other drawings.  
         [0046]     A number of materials can be used to generate oxygen, but the preferred mix is an aqueous solution of 7 to 10% hydrogen peroxide as first reaction material and reagent grade manganese as the second reaction material  18 .  
         [0047]      FIG. 3  is a cross-sectional view that shows more detail of the filter that is shown in  FIG. 1 . The filter includes a liquid trap  62 . An air line from the reaction vessel  12  enters the liquid trap  62  through a drip tube  76 . There is an air tube  78  located below the drip tube and out of alignment with it. As oxygen gas enters the liquid trap, it passes through the drip tube and enters the air tube, and passes through the filter chamber  66 . If any liquid enters through the drip tube  76 , it is retained in the liquid trap  62 , and only gas passes into the air tube  78 . Inside the filter chamber  66  are located filtering material that removes contaminants from the oxygen, so that only pure oxygen exits the filter chamber  66  and continues on to the face mask  68 . These filtering materials can take a number forms and these that are listed are the preferred form, although others are also suitable. The filter materials shown include several layers of activated charcoal  72  and other layers of foam or fibrous material  74 . The preferred foam or fibrous material is Heat Moisture Exchanger Foam (HME). Another foam that has been used successfully is called biosponge, which is made of natural sponge.  
         [0048]     An important feature of the design of the embodiment shown in  FIGS. 1 and 2  is that the end of the oxygen release tube  20  is not submerged in liquid in any orientation. This results in a unit that can produce oxygen when it is upside down, lying flat on its side or standing upright. Thus, once oxygen generation is initiated, it would continue in any orientation.  
         [0049]     In this embodiment, the second reaction material  18  and the first reaction material  14  are mixed by a user removing the locking cap  36  and then pressing the plunger button  80 . This would depress the plunger pin  30  and break the material of the ampule  26 . The material in the ampule  26  would then fall into the first reaction material or if the reaction chamber  12  is in another orientation, would mix with the first reaction material  14 .  
         [0050]     Another preferred embodiment of the invention is shown in  FIGS. 4, 5 , and  6 . Features of this embodiment are congruent with the previous embodiment, and are referred to by the same numbers, but in a  100  series. Thus, reaction chamber  12  is called  112 .  FIG. 4  shows an oxygen generation system  100 , which includes a flexible bladder  148 . The flexible bladder forms the reaction chamber  112 . Within the reaction chamber  112  is the first reaction material  114 . A second chamber is adjacent to and attached to the reaction chamber, and that is the second chamber  116 . Inside the reaction chamber  116  is located a second reaction material  118 . The two chambers are separated by a weak seal  142 . When the reaction chamber  112  is squeezed, the weak seal  142  between the two chambers ruptures and allows the two materials to mix. Once the two materials mix, oxygen is generated, as in the previous embodiment. Inside the flexible bladder  148  is an oxygen release tube  120 , to which is attached a float  144 . The float  144  is provided so that the end of the oxygen release tube  120  is always above the surface of the liquid. This is accomplished by the oxygen release tube  120  having enough flexibility to allow the float to stay above the liquid level. As oxygen is generated, it exits through the oxygen release tube  120  and passes through an air line clip  158 . The air line clip  158  would be removed in order to allow oxygen to pass through the conduit  150 . A filter chamber  166  is present and can take a number of configurations, including layers of activated charcoal and foam or fibrous filtration. From the filter chamber  166 , the conduit  150  continues on to a face mask  168 . The user applies the face mask  168  to his or another person&#39;s face to breath oxygen. The reaction is exothermic and thus an external carrying pouch  138  is useful. Once the reaction chamber  112  has been activated, it can be placed in the external carrying pouch  138  for carrying, keeping an upright, and preventing the heat of the reaction from burning a patient.  
         [0051]      FIG. 5  shows the reaction vessel of this embodiment placed on its side. In this orientation, the float  144  keeps the oxygen release tube  120  above the level of the first reaction material  114 . Shown is the adjacent second chamber  116  with its second reaction material  118 . The two chambers are separated by a weak seal  142 . Oxygen leaves the reaction chamber  112  via the conduit or tubing  150 , after the air line clip  158  is removed.  
         [0052]      FIGS. 6   a  through  6   d  show this embodiment of the oxygen generation system in operation. In  6   a , the conduit  150  with the attached face mask  168  is attached to the filter unit  166 . Thus, all the components are joined. In  FIG. 6   b , the user applies pressure to the reaction chamber  112  and breaks the weak seal  142 . When that occurs, the first reaction material  114  and the second reaction material  118  mix together. Upon mixing, oxygen is generated. At that point the air line clip  158  is removed from the conduit  150  and oxygen begins to flow out of the reaction chamber  112  and through the filter  166 .  
         [0053]     In  FIG. 6   c , the float  144  attached to the oxygen release tube  120  is visible and serves to keep the oxygen release tube  120  above the level of the liquid at all times.  
         [0054]     In  FIG. 6   d , the flexible bladder  146  is placed into the external carrying pouch  138 , from which oxygen continues to be generated and flow to the face mask  168 .  
         [0055]     Another embodiment of the invention is shown in  FIG. 7 .  FIG. 7  shows the flexible bladder  148  of the previous embodiment housed within a rigid outer container  170 . This embodiment operates basically the same as the previous embodiment, with the reaction chamber  112  being squeezed to rupture a weak seal  142 , thus allowing the mixing of the first reaction material  114  and the second reaction material  118 . An oxygen release tube  120  is shown in this device, attached to a float  144 . The oxygen release tube  120  of this device passes through the outer rigid container  170  and is held firmly in place by the outer rigid container  170 . Thus, this device holds the oxygen release tube  120  in a position so that it is not submerged in liquid in any orientation. The use of an air line clip, an indicator chamber, liquid trap, check valve, filter chamber, conduit, and air mask are all the same with this embodiment.  
         [0056]     Another embodiment of the invention is shown in  FIG. 8 . This embodiment is similar to the second embodiment shown, but rather than a weak seal separating the reaction chamber and the second chamber, in this embodiment a separation membrane  146  separates the two. When the bag is squeezed the separation membrane is weaker than the flexible bladder  148  and ruptures. Once the separation membrane ruptures, the first reaction material can mix with the second reaction material and begin generating oxygen. This embodiment shows the presence of a hydrophobic filter  154 , a humidifying chamber  156 , and a chemical filter  166  all mounted on the conduit  150  leaving to the face mask  168 . These are optional devices placed in the path of out flowing oxygen generated in the oxygen generating system.  
         [0057]     The material used to make the flexible bladder  148  and the separation membrane  146  can take various forms. One combination of materials that has been found to work well is to utilize 6 mil thick polypropylene or other polymer material for the flexible bladder, and to utilize 12 mil thick polypropylene for the separation membrane  146 . The separation membrane  146  is attached to the inside wall of the flexible bladder  148  by heat sealing. Other means of attaching the separation membrane  146  to the flexible bladder  148  are possible, including chemical fusing, sonic bonding or other techniques that are known in bag making technologies.  
         [0058]     At the upper end of the flexible bladder  148  is an oxygen tube  120 . The oxygen tube  120  is integral with the wall of the flexible bladder  148 , and defines a route for oxygen to exit the flexible bladder  148 . Attached to the oxygen tube  120  is a delivery conduit  150 . This would typically be a piece of plastic tubing. Tubing with an inside diameter of {fraction (5/32)}″ has been found to be adequate for this purpose.  
         [0059]     While there is shown and described the present preferred embodiment of the invention, it is to be distinctly understood that this invention is not limited thereto but may be variously embodied to practice within the scope of the following claims. From the foregoing description, it will be apparent that various changes may be made without departing from the spirit and scope of the invention as defined by the following claims.