Abstract:
A lightweight, portable, reusable oxygen generator is provided. The oxygen generator comprises a reaction chamber, a humidifier, and a cap assembly. Once assembled, oxygen of medical purity can be generated in the reaction chamber via a chemical reaction. Then, the medically pure oxygen is separated from any the aqueous reaction mixture and ported via a built-in humidifier to a CPR mask through a tube attached to the oxygen generator.

Description:
CROSS-REFERENCED APPLICATIONS  
       [0001]     This application relates to a co-pending U.S. patent application Ser. No. 10/718,131 entitled “METHOD AND APPARATUS FOR GENERATING OXYGEN” (Docket No. ROSS 2864000), filed Nov. 20, 2003, which is hereby incorporated by reference for all purposes. 
     
    
     FIELD OF THE INVENTION  
       [0002]     The present invention relates generally to the production of medically pure oxygen and, more particularly, to apparatus and methods of delivery of medically pure oxygen.  
       DESCRIPTION OF THE RELATED ART  
       [0003]     Oxygen generators using chemical reactions have been known for some time, and the principles governing the chemical reaction driving the oxygen production are well documented. However, none of the conventional devices relating to chemical oxygen generators have resulted in medically pure oxygen becoming an easily accessible, inexpensive, over-the-counter consumer item, nor have they resulted in it becoming a standard-issue item for public and private emergency-response personnel and locations. In addition, conventional generators have not been widely adopted in commerce and industry. There are several possible factors contributing to this lack of interest, including one or a combination of unfavorable characteristics relating to reusability, safety, ease of use/operation, speed of use, heat management, cost, weight, aesthetic design, environmental impact, manufacturability, portability, medical efficacy, effectiveness, flow rate, oxygen yield, reaction stability, and oxygen purity. Some or all of these characteristics are not addressed, or are inadequately addressed, by conventional devices.  
         [0004]     Conventional designs have not adequately addressed elimination of heat generated by the exothermic chemical reaction involved, without adversely affecting other factors such as cost and weight, for example. The heat generated by the chemical reaction can prevent the user from handling the generator itself with bare hands, either during or immediately following the reaction cycle. Efforts to address this shortcoming have reduced the portability and utility of the product.  
         [0005]     Another issue is related to flow rate and to total oxygen yield. Conventional designs have not adequately addressed the associated consequences of more stringent performance requirements for flow rate and total oxygen yield, particularly in emergency and safety applications where higher flow rates are required, and, in some cases mandated by regulatory authorities. For example, the United States Food and Drug Administration (FDA) has long required a flow rate performance of at least 6 liters per minute over 15 minutes in order to obtain market clearance for over the counter purchase, resulting in a total oxygen yield requirement of 90 liters. Higher flow rates over a sustained period typically are accompanied by increased heat being generated by the chemical reaction. In addition, higher pressures being generated inside the reaction chamber generally accompany higher flow rate outputs or requirements.  
         [0006]     The reaction chamber is a closed environment with typically at least one “exit point” for the oxygen generated. The higher pressure causes the aqueous reaction mixture to advance in the same direction and under the same pressure conditions as the oxygen being generated. A consequence is the dangerous possibility that some of the aqueous reaction mixture or some of the particles from the chemical reaction components will travel with the oxygen generated, into the user&#39;s lungs. Higher flow rates can also result in leakages and consequently safety concerns.  
         [0007]     Therefore, a need exists for a method and/or apparatus for producing medically pure oxygen that addresses at least some of the problems associated with conventional methods and apparatus for producing medically pure oxygen.  
       SUMMARY OF THE INVENTION  
       [0008]     The present invention provides an apparatus for delivering medically pure oxygen. An inner sleeve that contains an oxygen producing chemical reaction. The inner sleeve is contained within an outer housing. An insulating space or layer is interposed between at least a portion of the sleeve and housing. An oxygen transmission channel extends from and is in fluid communication with the contents of the inner sleeve.  
         [0009]     In one aspect of the invention, a humidifier coupled to the oxygen transmission channel humidifies and filters the oxygen.  
         [0010]     In another aspect of the invention, a cap holds together the sleeve and housing. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0011]     For a more complete understanding of the present invention and the advantages thereof, reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which:  
         [0012]      FIG. 1  is a front elevation view of the assembled generator dispenser according to present invention;  
         [0013]      FIG. 2  is a sectional view along  2 - 2  of  FIG. 1 ;  
         [0014]      FIG. 3  is a perspective view of the exploded or disassembled components of the generator dispenser according to present invention;  
         [0015]      FIG. 4  is a front elevation view of the exploded or disassembled components of the base of the generator, comprising the reaction chamber exterior housing and the reaction chamber inner sleeve;  
         [0016]      FIG. 5  is a perspective top view of the reaction chamber exterior housing and the reaction chamber inner sleeve;  
         [0017]      FIG. 6  is a sectional front view of the assembled reaction chamber exterior housing and the reaction chamber inner sleeve along  6 - 6  in  FIG. 4 ;  
         [0018]      FIG. 7  is a perspective view of the humidifier assembly;  
         [0019]      FIG. 8  is a front elevation view of the exploded or disassembled components of the humidifier assembly, comprising the humidifier body and the humidifier base;  
         [0020]      FIG. 9  is a sectional front view of the humidifier assembly along  9 - 9  in  FIG. 7 ;  
         [0021]      FIG. 10 ,  FIG. 11  and  FIG. 12  are perspective views of the humidifier base from different angles;  
         [0022]      FIG. 13  is a view on section  13 - 13  of  FIG. 11 ;  
         [0023]      FIG. 14  is a perspective view of the exploded or disassembled components of the humidifier assembly and the membrane stack;  
         [0024]      FIG. 15  is a perspective view of the exploded or disassembled components of the membrane stack;  
         [0025]      FIG. 16  is a front elevation view of the humidifier body;  
         [0026]      FIG. 17  and  FIG. 18  are perspective views of the top and the bottom, respectively of the humidifier body;  
         [0027]      FIG. 19  is front elevation view of the cap of the generator dispenser;  
         [0028]      FIG. 20  is a perspective view of the exploded or disassembled components of the cap and “outer stem” assembly;  
         [0029]      FIG. 21  is a view on section  21 - 21  of  FIG. 19 ;  
         [0030]      FIG. 22 ,  FIG. 23  and  FIG. 24  are perspective views of the “outer stem”;  
         [0031]      FIG. 25  is a view on section  25 - 25  of  FIG. 24 ;  
         [0032]      FIG. 26  is a front elevation of the cap of the generator dispenser;  
         [0033]      FIG. 27  is a perspective view of the bottom of the cap of the generator dispenser; and  
     
    
     DETAILED DESCRIPTION  
       [0034]     In the following discussion, numerous specific details are set forth to provide a thorough understanding of the present invention. However, those skilled in the art will appreciate that the present invention may be practiced without such specific details. In other instances, well-known elements have been illustrated in schematic or block diagram form in order not to obscure the present invention in unnecessary detail.  
         [0035]     Referring now to  FIGS. 1, 2  and  3  of the drawings, a dispenser is shown comprising a reaction chamber exterior housing  100 , a reaction chamber inner sleeve  150  which fits advantageously into the reaction chamber exterior housing  100 , a humidifier base  200 , a humidifier body  300 , an outer stem  360  and a cap  400 . These components fit together to form the assembled generator shown in  FIG. 1 . Also, the outer housing  100  and the reaction chamber are typically cylindrical. The reaction chamber inner sleeve  150  slides into the reaction chamber exterior housing  100  as illustrated by  FIG. 4 . The reaction chamber inner sleeve  150  can then adhere to the reaction chamber exterior housing at a lip boundary  152  in  FIG. 2 . Adherence of the reaction chamber to the can be accomplished through a variety of methods that include, but is not limited to, chemical bonding (such as epoxy) and thermal fusing (such as welding or melting together).  
         [0036]     Additionally, the reaction chamber exterior housing  100  and the reaction chamber inner sleeve  150  can also be adhered to each other at various other locations. More particularly, the reaction chamber inner sleeve  150  at any point of contact with exterior housing  100 , or the reaction chamber inner sleeve  150  and the reaction chamber exterior housing  100  can also be manufactured as one single component. By having the reaction chamber  150  and the exterior housing  100  manufactured as a single component, the need for an adhesive can be eliminated, and the integrity and strength of the reaction chamber  150  can be increased.  
         [0037]     The reaction chamber  150  can also incorporate a “draft” into its design. A draft can facilitate or support a plastic injection molding process as a means of commercial production. For example, the draft can include a 1.5-degree angle between the vertical plane and the plane of the reaction chamber exterior housing as shown in  FIG. 1 . Other angles can also be employed. However, the reaction chamber inner sleeve  150  will typically employ the same draft angle as the reaction chamber exterior housing  100 .  
         [0038]     The sides of the reaction chamber inner sleeve  150  and the sides of the reaction chamber exterior housing  100  are separated from one another by a series of side ribs  160  illustrated in  FIG. 5 , attached to and placed equidistantly around the surface of the reaction chamber inner sleeve  150 . The side ribs  160  can also be attached to and placed equidistantly around the surface of the reaction chamber exterior housing  100 . However, if a plastic injection molding method of commercial production is used, then these side ribs  160  may cause “shadows” on the outer surface of the reaction chamber exterior housing  100 , thereby causing adverse aesthetic effects. The bottom of the reaction chamber inner sleeve  150  and the bottom of the reaction chamber exterior housing  100  are separated from each other by a series of bottom ribs  120  illustrated in  FIG. 5  and  FIG. 6 .  
         [0039]     These bottom ribs  120  can be designed to extend radially from the cylindrical axis of the outer housing (not shown) and are attached to the inside bottom of the reaction chamber exterior housing  100 .  FIG. 2  and  FIG. 6  illustrate how the design creates a space  154  between the reaction chamber inner sleeve  150  and the reaction chamber exterior housing  100 . This space creates a very effective “air insulator”, serving to reduce, minimize or prevent the heat generated from the exothermic chemical reaction inside the reaction chamber inner sleeve  150  from reaching the outer surface of the reaction chamber exterior housing  100 . The air insulation created by the space  154  illustrated in  FIG. 2  and  FIG. 6  is significantly effective in ensuring that the user of the oxygen generator can comfortably and safely handle the generator directly with bare hands, during, or after the chemical reaction cycle.  
         [0040]     The side ribs  160  typically extend from the lip boundary  152  to a point just above the position of the bottom ribs  120 . Essentially, the side ribs  160  provide a contact surface between the reaction chamber outer housing  100  and the reaction chamber inner sleeve  150  nearly parallel to the cylindrical axis to reaction chamber outer housing  100  and the reaction chamber inner sleeve  150 . However, because the side ribs  160  are at and below the lip boundary  152 , the ribs are hidden from view once assembled. A reason for having side ribs  160  and bottom ribs  120  is to provide spaces  154  or an insulation gap between the reaction chamber inner sleeve  150  and the reaction chamber outer housing  100  that will limit, reduce or otherwise minimize the transfer of heat between the inside of the reaction chamber inner sleeve  150  and the outer surface of the reaction chamber outer housing  100 , thereby enhancing the ability of the user to comfortably operate the generator with bare hands, both during and upon completion of the chemical reaction cycle.  
         [0041]     In addition to creating the spaces  154  illustrated in  FIG. 2  and  FIG. 6 , which serve as an effective “air insulator,” the ribs  120  and  160  illustrated in  FIG. 5  also serve to significantly strengthen the reaction chamber by reinforcing both the reaction chamber exterior housing  100  and the reaction chamber inner sleeve  150 . A much more effective resistance to pressure build-up (during the chemical reaction) can then be provided inside the reaction chamber than is currently provided. The use of ribs  120  and  160  would provide additional material to combat stress, strain, and, possibly, torsion that result from internal pressures by improving the tensile strength of the reaction chamber.  
         [0042]     As an additional example, an additional material can be utilized instead of air. A material, such as a high strength epoxy can fill the gap that results from the separation between the reaction chamber  150  and outer housing  100 . Thus, a single wall design with an inserted material would then have similar strength properties to one with an air gap, but also have the benefit of being completely solid.  
         [0043]     Because the reaction to produce oxygen is an exothermic reaction, insulation from the reaction is desirable. The heat transfer from the chemical reaction to the surface of the reaction chamber exterior housing  100  can be further reduced or minimized by the material selection for the reaction chamber exterior housing  100  and the reaction chamber inner sleeve  150 . Typically, each of the materials chosen has an R-factor above about 1.5. For example, the reaction chamber inner sleeve  150  can be made of Polycarbonate, and the reaction chamber exterior housing  100  can be made of Acrylonitrile Butadiene Styrene. Other plastics or materials such as Polypropylene or Polyethylene can also be used for either the reaction chamber exterior housing  100 , or the reaction chamber inner sleeve  150 .  
         [0044]     The selection of Polycarbonate for the reaction chamber inner sleeve  150  is particularly advantageous for the physical properties of this material. Polycarbonate is a tough, dimensionally stable, transparent thermoplastic that is well suited to applications that demand high performance properties. From a commercial production point of view, Polycarbonate is widely available and accessible, and constitutes a versatile thermoplastic, which maintains its properties over a wide range of temperatures. Polycarbonate has the highest impact strength of any thermoplastic, and has outstanding dimensional and thermal stability, high tensile strength, good chemical resistance, exceptional machinability, low thermal conductivity and is non-toxic with low water absorption. The selection of Acrylonitrile Butadiene Styrene for the reaction chamber exterior housing  100 , on the other hand, is advantageous for its lower (than Polycarbonate, for example) cost, while providing a rigid thermoplastic material that has high impact strength, high tensile strength and good machinability. However, there are also a variety of other polymers, plastics, and composite materials that can be used.  
         [0045]     Furthermore, various wall thicknesses can be used for the reaction chamber exterior housing  100  and the reaction chamber inner sleeve  150 . Examples for the wall thicknesses for the reaction chamber exterior housing  100  and the reaction chamber inner sleeve  150  include 0.093 inches and 0.125 inches respectively. However, the thickness of the walls can be varied according to either desire or need that is based on such considerations as the materials chosen and the thermal output of the reaction.  
         [0046]     Referring to  FIG. 7 ,  FIG. 8  and  FIG. 9 , the humidifier base  200  is removable from the humidifier body  300 . The humidifier base  200  incorporates inner thread (female)  202 , which mates with the outer thread (male)  302  incorporated in the humidifier body  300  for easy and rapid unscrewing to remove and screwing back to replace. Three turns of inner thread  202  and outer thread  302  relative to each other can be used.  
         [0047]     Once the humidifier base  200  and the humidifier body  300  are assembled, a plenum  250  is created. This plenum  250  is used to house the membrane stack  260 , illustrated in  FIG. 14  and  FIG. 15 . The removability of the humidifier base  200  allows for easy inspection of the membrane stack  260  housed in the plenum  250 . In addition, the removability of the humidifier base  200  allows for easy and frequent replacement of any or all of the components of the membrane stack  260  housed in the plenum  250 . Also, both the humidifier base  200  and the humidifier body  300  can be made of Polycarbonate or another polymer.  
         [0048]     Referring to  FIG. 10 ,  FIG. 11 ,  FIG. 12  and  FIG. 13 , the design of the humidifier base  200  includes an annular faceplate  208 , which incorporates porosity, as to allow increased airflow to pass through to the plenum  250 . The annular faceplate  208  also serves to rigidly support the membrane stack  260  above it.  
         [0049]     The annular faceplate  208 , however, can affect the airflow. Enhanced porosity can be achieved, for example, through circular apertures  210  in the annular faceplate  208 . The shape of the apertures  210 , however, can vary. The apertures  210  can be made sufficiently large in order to minimize any clogging of the membranes supported above the annular faceplate  208 . Another way to prevent membrane clogging and to improve the performance of the membrane housing, in general, is to vary the contact angle with the air flow of the annular faceplate  208 . An example is to vary the angle from 90° to something less than 90°, such as 65°.  
         [0050]     The humidifier base  200  also incorporates several other features. A “grip detail”  212  is provided, which allows for enhanced grip (when removing/unscrewing or tightening) and easier user handling. A thread “lead-in”  214  is also provided to allow for faster and easier tightening. The thread lead-in  214  is a gap that extends above the inner thread (female)  202 , so that when coupled with the outer thread (male)  302  there is not an immediate need for threading. In addition, the humidifier base  200  is reinforced with a series of angular ribs  204  to provide additional rigidity and strength to resist the upward pressure from the direction of the airflow and chemical reaction.  
         [0051]     Utilizing a membrane stack  260 , as illustrated in  FIG. 14  and  FIG. 15 , improves filtration efficiency significantly. The different-components of the membrane stack  260 , however, serve different functions. The first component of the membrane stack  260  consists of a pre-filter  222 , the role of which is to remove or retain the majority of any chemical reaction particles or aqueous chemical solution and prevent same from entering or reaching the second tier of the membrane stack.  
         [0052]     The pre-filter  222  is cost-effectively replaceable after every single chemical reaction or after every single use of the oxygen generator. The usage and lifespan of the other, more expensive, membranes in the stack can, thus, be increased due to the replacability of the pre-filter. Examples of pre-filters that can be used include glass fiber filter papers or binder-free glass microfiber filters. However, there are a variety of materials that can be utilized to form the pre-filters. The most practicable size for the pores of the pre-filter  222  is approximately 10 microns. The pre-filter  222  can also be preceded by a “foam-breaker”, which could be a stainless steel mesh and can serve to filter coarse particles.  
         [0053]     The functions of the second membrane  224  are to provide rigid support for the main phase separation membrane  226  and to provide additional filtration. During the chemical reaction, the airflow can exert significant pressure on the membranes. These pressures exerted on membranes used to separate the oxygen from any chemical reaction components/particles and any aqueous chemical solution can be very high, especially at the higher flow rates above  6  liters per minute. The second membrane  224  consists of a porous plastic and can be 0.250 inches thick. However, a variety of other materials and thicknesses can be employed.  
         [0054]     The porous plastics used in the second membrane  250 , however, contain an intricate network of open-celled, omni-directional pores. These pores, which can have average pore sizes as low as one micron, give porous plastics their unique combination of filtering capability and structural strength. Unlike the direct passages in woven synthetic materials and metal screens, the pores in porous plastic join to form many tortuous paths. Porous plastics have dual filtering capability. Not only do they act as surface filters by trapping particles larger than their average pore size, they also trap much smaller particulate matter deep in their complex channels, for a “depth filter” effect. Therefore, the efficiency of this tortuous path structure is such that porous plastics with an average pore size of 25 microns offer approximately the same filtration as five micron-rated filter media. The most practicable size for the pores of the second membrane  224  appears to be 10 microns, although a pore size rating of 10 microns through 30 microns can also be used.  
         [0055]     The third membrane  226  provides final separation of the oxygen and any remaining aqueous solution or particle matter, resulting in medically pure oxygen being passed through to the humidifier  300 . This third membrane  226  is designed to be Inherently hydrophobic for aqueous clarification and particulate capture. Also, the third membrane  226  should be compatible with strong acids and aggressive solutions and should be consistent with high flow rates for faster filtration Superior durability is also desirable.  
         [0056]     The pore sizes for the third membrane  226  are usually smaller than the other membranes. Suitable pore sizes for the third membrane  226  can range anywhere from 0.1 microns to 10.0 microns, depending on flow rates desired. Examples of membranes that can be used include Polytetrafluoroethylene and Nylon membranes; however, a variety of other materials can also be used to form the membranes.  
         [0057]     The fourth membrane  228  provides optional “downstream” support for the third membrane  226 . It can consist of a porous plastic. Examples may include a 0.125 inch thick Polytetrafluoroethylene porous plastic, although other materials and thicknesses can be used.  
         [0058]      FIG. 14  and  FIG. 15  also show an annular disc  230 . The annular disc  230  is designed to provide downstream rigid support for the membrane stack  260 . The annular disc  230  provides for maximum oxygen flow into the humidifier body  300  through a series of apertures  232 . Also, the annular disc  230  can be adhered to the annular face  252 , shown in  FIG. 18 . Adhering the annular disc  230  to the annular face  252  ensures that users do not inadvertently forget to replace the annular disc  230  after removing the membrane stack  260  for inspection or replacement purposes.  
         [0059]      FIG. 18  illustrates an aperture  308  through which the purified oxygen flows into the inner stem  350 , also shown in  FIG. 17 . The support provided by the annular disc  230  can ensure that the pressurized airflow, particularly at high flow rates, does not cause the membranes to bow into or be forced into aperture  308 . The annular disc  230  can be made of Polycarbonate. The diameters of the membrane stack  260  and of the annular disc  232 , both of which can vary, are selected in this invention to be 47 mm in diameter.  
         [0060]     Referring to  FIG. 16 ,  FIG. 17 , and  FIG. 18 , the humidifier body  300  has an annular flange  310 . The annular flange  310  isolates the reaction chamber formed by the reaction chamber inner sleeve  150 . By isolating the reaction chamber, most of the chemical reaction can be sealed off as the annular flange  310  seats advantageously on the flat circular surface of the lip  156  at the top of the reaction chamber inner sleeve  150  shown in  FIG. 5 . The annular flange  310  is then reinforced with bottom ribs  304  and the top ribs  306 , arranged axially to increase rigidity. The bottom ribs  304  and the top ribs  306  are staggered in terms of their placement opposite each other. For example, if the top ribs  306  are spatially arranged to be located at 0°, 90°, 180°, 270°, then the bottom ribs  304  are arranged to be at 45°, 135°, 225° and 315°, as illustrated in  FIG. 16 .  
         [0061]     The staggered design further enhances the reinforcement effect of the ribs on the annular flange  310 . By having ribs, such as the bottom ribs  304 , staggered, there are no extended surfaces that can deform, bow, crack or move as a result of pressures. The ribbed design also effectively counteracts the upward pressure on the annular flange  310  by the positive pressure generated during the chemical reaction.  
         [0062]     The humidifier body  300  also has predetermined minimum and maximum water levels  320  and  322 , respectively. The minimum and maximum water levels  320  and  322 , respectively, provide an easy, viewable guide, allowing the user to fill the humidifier body  300  with water to a pre-determined level prior to commencing the chemical reaction. The primary purpose of the water in the humidifier body  300  is to hydrate the oxygen produced. This hydration is achieved when the oxygen, flowing in a downward direction inside the outer stem  360  ( FIG. 21 ) is diffused by the slats  362  ( FIG. 23 ). After the diffusion, warm oxygen flows through the water added by the user in the humidifier body  300 , causing water vapor and oxygen molecules to mix. The slats  362  act as “diffusion ports”, creating improved hydration of the oxygen, while at the same time reducing system back pressure. The humidification process maintains a desirable level of oxygen saturation. The user ultimately breathes medically acceptable, hydrated oxygen, which translates into oxygen that is comfortable to breathe and not dry, as can be the case with many “traditional” oxygen devices.  
         [0063]     Another component of the humidifier is the inner stem  350 . The inner stem  350  is tapered such that the top aperture  352  is smaller in diameter than the diameter of bottom aperture  308 , creating a nozzle. The taper effect allows for easy and convenient location of the inner stem  350  by the outer stem  360 , shown in  FIG. 19  and  FIG. 20 , upon closing of the generator by twisting on the cap  400 , which is also shown in  FIG. 19  and  FIG. 20 .  
         [0064]     The humidifier body  300  also has a series of flat ribs  316  inside at its base. These flat ribs  316  are arranged radially from the base of the inner stem  350 . These flat ribs  316  have ends  318  that are angled towards the base of the humidifier body  300 . The flat ribs  316  serve to center the outer stem  360  upon closing of the generator. The angle of the lip  372  at the base of the outer stem  360  forces the outer stem to a center axial position by mating and fitting advantageously over the ends  318  of the flat ribs  316 .  
         [0065]      FIG. 19  and  FIG. 20  illustrate the cap assembly, which includes the cap  400  and the outer stem  360 . The outer stem  360  is attached to the cap  400  at a boundary  370 . The outer stem  360  is attached to the cap  400  by adhering it to the sides of the cavity  428  at  370 , as illustrated by  FIG. 20 . Alternatively, the cap assembly consisting of cap  400  and the outer stem  360  can be manufactured (using a process such as injection molding) as one piece. An advantage to the user of having the cap assembly as one piece is that it significantly facilitates rapid closure of the generator, while at the same time sealing off the humidifier and positioning the inner stem  350  and outer stem  360  correctly. Having a single cap  400  and outer stem  360  comprise a single piece is particularly helpful in medical emergency situations, where time is of the essence, and precious seconds can make a difference in saving a life.  
         [0066]     Independently, the outer stem  360  has a bottom aperture  364  (shown in  FIG. 23 ), and is tapered to match the taper angle of the inner stem  350 . The bottom of the lip  374  of the outer stem  360  is flat and makes contact with the inside base of the humidifier body  300  upon closure of the generator. In addition, the surface  376  rests on the bottom ribs  316  once the generator is closed for additional stability and to prevent any “rattling” or “vibration” due to the oxygen flow during the reaction.  
         [0067]     At the base of the outer stem  360  there are several slats  362 , located substantially equidistant apart, as is shown in  FIG. 22  and  FIG. 23 . These slats  362  allow for oxygen to pass through at high flow rates. However, apertures or holes can also be used instead of slats. The slats  362 , though, cause the oxygen flowing through them to be diffused, providing superior oxygen hydration while at the same time facilitating quiet operation and reducing system back pressure. Toward the top of the outer stem  360  there is a flow barrier  366  that acts as a shut-off. The top of the outer stem  360  is designed to mate into the cavity  428 , as shown in  FIG. 27 .  
         [0068]     Referring to  FIG. 26  and  FIG. 27 , the cap  400  has outer threads  402 , which mate with the inner thread  112  of the reaction chamber exterior housing  100 , creating an airtight seal. While any number of threads can be used, typically no more than three turns are preferred for faster closure. Inserting a gasket (not shown) or an O-ring (not shown) between the cap  400  and the reaction chamber  150  can further enhance air-tightness.  
         [0069]     Additionally, the cap  400  has flange  404 , which seats on the top of reaction chamber exterior housing  100  upon closure of the dispenser. The thread  402  is accommodated in such a manner as to allow the inside wall of the reaction chamber inner sleeve  150  to be substantially flush with the inside wall surface  430  of cap  400  by the use of a bell housing design  110 , as illustrated in  FIG. 4 . The cap  400  further has exterior ribs  406 , serving the functional purpose of facilitating user grip (for twisting/closing or untwisting/opening of the cap  400 ), as well as serving an aesthetic purpose.  
         [0070]     The cap  400  also includes some other features. By designing the cap  400  with the insets  412 , the user is able to more easily handle the cap  400 , even if the user has smaller hands. The cap  400  has a recessed nipple outlet  410  through which the oxygen is expelled. The user can attach a tube (attached to a CPR mask) or cannula to the recessed nipple outlet  410 .  
         [0071]     Underneath the cap  400  there is a cavity  420 , which completes the top half of the humidifier. The inside wall forming the cavity  420  and the inside wall of humidifier body  300  are preferably substantially flush upon closure. The substantial flushness is achieved through an offset  422 , such that the top edge  362  of the humidifier body  300  slides into the offset  422  upon closure, coming to rest at  424  and sealing off the humidifier from the rest of the generator. The cap  400  can be made of clear Polycarbonate.  
         [0072]     Once closed and the chemical reaction has commenced, the oxygen is expelled from the membrane stack  260 , which flows through the annular disc  230 , and enters the humidifier body  300  through inner stem  350  via the inlet provided by aperture  308 . The oxygen exits the inner stem  350  at its top aperture  352 , proceeding away from the reaction chamber  150 . The oxygen is then forced into the opposite direction, toward the base of the humidifier body  300 , by the flow barrier  366  located towards the top of the outer stem  360 . The oxygen flows to the bottom of outer stem  360  and exits through the slats  362 . At this point, the oxygen enters the water inside the humidifier body  300 , bubbling through the water and being hydrated in the process. The hydrated oxygen can then proceed into plenum  426 . The oxygen then enters the top of the outer stem  360  through the slats  368 , as shown in  FIG. 24 , enters plenum  428 , and then exits the generator through the recessed nipple outlet  410 .  
         [0073]     It is preferable to maintain control of the flow of oxygen. For this purpose, valve (not shown) can be used to regulate the flow of oxygen out of the cap  450 . A variety of types of regulator valves can be utilized to control the flow of oxygen. Preferably, such a regulator valve would be coupled to the nipple  410  of the cap  450 . Alternatively, a pressure regulator could be used in place of a regulator valve, to automatically adjust the pressure or flow rate of expelling oxygen to a desired set point or range.  
         [0074]     Additionally or alternatively, oxygen flow rates can be controlled or regulated by varying the number or thickness of the layers of coating covering the particles of the oxygen releasing agent (usually in powder form) used in the chemical reaction. Flow rates can also be controlled through selection of the particle size of oxygen releasing agent. Clearly, flow rates can also be controlled through a combination of these three factors.  
         [0075]     It is understood that the present invention can take many forms and embodiments. Accordingly, several variations may be made in the foregoing without departing from the spirit or the scope of the invention. The capabilities outlined herein allow for the possibility of a variety of programming models. This disclosure should not be read as preferring any particular programming model, but is instead directed to the underlying mechanisms on which these programming models can be built.  
         [0076]     Having thus described the present invention by reference to certain of its preferred embodiments, it is noted that the embodiments disclosed are illustrative rather than limiting in nature and that a wide range of variations, modifications, changes, and substitutions are contemplated in the foregoing disclosure and, in some instances, some features of the present invention may be employed without a corresponding use of the other features. Many such variations and modifications may be considered desirable by those skilled in the art based upon a review of the foregoing description of preferred embodiments. Accordingly, it is appropriate that the appended claims be construed broadly and in a manner consistent with the scope of the invention.