Abstract:
A method and a system for providing a hypoxic environment inside an enclosed compartment with simultaneous removal of carbon dioxide and moisture produced by occupants; said method and system designed for fire prevention and for simulated altitude training, wellness and hypoxic therapy, including equine and other animal applications.

Description:
[0001]    This application is a continuation in part of the U.S. Ser. No. 10/726,737; U.S. Ser. No. 11/183,948 and U.S. Pat. Nos. 7,207,392; 6,418,752; 6,401,487; 6,314,754; 5,964,222; 5,887,439 and 5,799,652. 
     
    
     FIELD OF THE INVENTION AND PRIOR ART 
       [0002]    The present invention introduces a method of producing comfortable human-breathable hypoxic atmospheres within confined compartments. Hypoxic environments described in earlier patents provided above being currently used for hypoxic training and therapy, and fire prevention worldwide—sufficient information can be obtained from www.hypoxico.com and www.firepass.com. 
         [0003]    However, in many cases the capacity of hypoxic generators producing such environments does not allow to provide sufficient ventilation rate in order to effectively remove carbon dioxide, water vapor and odors produced by occupants, especially during hypoxic exercise or heavy physical work load. In order to reduce carbon dioxide and water content in such environments, either the capacity (and cost) of the generators must be increased or separate air treatment systems utilizing mostly chemicals needs to be installed. 
         [0004]    Current invention allows saving on manufacturing, servicing and energy cost by providing a method and a single system that will:
       Produce healthy hypoxic atmosphere for a human user or an animal   Remove excessive carbon dioxide and water vapor from the environment   Control oxygen and carbon dioxide content within preset parameters   Significantly reduce the size, cost and energy consumption of the equipment needed       
 
         [0009]    With its mode of action based on producing and maintaining hypoxic environment within a range of preset parameters of oxygen and carbon dioxide content and desired humidity, this human-friendly system is completely non-toxic, simple and reliable. Consequently, this method is ideally suited to provide a comfortable for respiration environment with oxygen content between 10% and 20.9% and carbon dioxide content in the range from 0.0035% to 3%, for applications that may include fire prevention or hypoxic training and therapy, etc. Alternatively, this method of carbon dioxide and moisture removal can be applied to normoxic and hyperoxic environments as well. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]      FIG. 1  presents a schematic view of the first preferred embodiment of the system for controlling carbon dioxide and moisture in an enclosed environment 
           [0011]      FIG. 2  illustrates an alternate embodiment of the system for controlling carbon dioxide and moisture in a hypoxic (or hyperoxic) environment 
       
    
    
     DESCRIPTION OF THE INVENTION 
       [0012]    This reliable and low-cost solution will allow designing and building environmentally friendly, cost- and energy-efficient systems for producing and maintaining hypoxic environments in occupied enclosed compartments. 
         [0013]    The invented equipment producing such environments can be used for fire prevention inside of an aircraft and ground vehicles, submarines, space vehicles and stations, data centers, archives, warehouses and other occupied structures. Additionally, it can be used for simulating altitude for athletic or equine training or therapy, weight loss and other wellness application benefiting from exposure to hypoxic atmospheres. The invented method can be also applied for controlling carbon dioxide and moisture in normoxic and hyperoxic enclosed environments. 
         [0014]    The invention utilizes a special air separation device  11  that recycles internal atmosphere from the enclosed environment  10 . The device  11  draws internal air via inlet A and extracts from it a gas mixture rich enriched with carbon dioxide, water vapor and some oxygen, and disposing this gas mixture via outlet B. The remaining fraction, which is reduced in carbon dioxide, water and oxygen, returns back into environment  10 . The loss of the internal atmosphere will be compensated for hermetic environments by fresh ambient air sent by air-supply device (e.g. blower or fan)  16  via inlet D. In this case device  16  can be operated by a pressure transducer  17  and/or by a control panel  12 . In semi-airtight compartments fresh air supply can occur automatically leaking through holes and gaps in the compartment structure. The driving force of this automatic fresh air supply will be the pressure difference due to extraction of carbon dioxide and moisture enriched gas mixture from the compartment. Device  16  and transducer  17  should be eliminated in this case. 
         [0015]    The environment  10  should be slightly pressurized in applications such as aircraft, military vehicles or data centers in order to prevent the loss of the atmosphere in aircraft or to prevent dust and contaminants from entering the environment  10 . 
         [0016]    Control panel  12  is equipped with oxygen sensor  13 , carbon dioxide sensor  14  and humidity sensor  15 . Additionally it can be equipped with temperature control as described in earlier patents and other gas sensors, such as ammonia sensor for equine stables, etc. 
         [0017]    Using feedback data from sensors  13 ,  14  and  15  and preset values, control panel can achieve and maintain a desired hypoxic environment condition by controlling the flow of the fresh air supply via device  16  and operation of the device  11 . 
         [0018]      FIG. 2  shows another embodiment that can be used in application where a quick achievement of hypoxic condition and/or higher degrees of hypoxia desired (e.g. for research or acclimatization purposes). This embodiment utilizes practically the same equipment and has an additional hypoxic generator  28  injecting hypoxic air, when needed, via inlet E, while disposing oxygen enriched fraction via outlet F. 
         [0019]    In some cases, fresh air supply device  26  can be eliminated and hypoxic generator  28  can supply hypoxic air with different oxygen content or even ambient air. In some applications, hypoxic generator  28  can be replaced with an oxygen concentrator for producing hyperoxic environment that can also be maintained by removing carbon dioxide and moisture using device  21 . 
         [0020]    In the embodiment shown on  FIG. 2 , the air separation device  11  becomes  21  and device  16  becomes  26 . An advanced control panel  22 , having oxygen sensor  23 , carbon dioxide sensor  24  and an optional humidity sensor  25 , can control all three devices  21 ,  26  and  28 . An optional pressure transducer  27  may be installed in hermetic compartments. Hypoxic generator  28  has been described in detail by previous patents provided above and the size and capacity of it can be about 30% to 50% of the required in current application. This system has a valuable benefit of controlling carbon dioxide content in applications where it is essential (e.g. research, simulated altitude training and medical field). 
         [0021]    Both, hypoxic generator  28  or device  21  can produce and maintain hypoxic environment even if the compartment  20  is not in use. Once necessary parameters achieved, control panel can turn the system off and on in a cycling manner in order to maintain set parameters. 
         [0022]    Once the compartment  20  is in use and CO2 and/or humidity level increases, device  21  starts working, reducing CO2 and/or humidity content to the desired values. 
         [0023]    Both embodiments allow to creating a comfortable for respiration environment with oxygen content between 10% and 20.9% and carbon dioxide content in the range from 0.035% to 3%, for applications that may include fire prevention or hypoxic training and therapy, etc. For both embodiments, a dedicated or split air-conditioning system is recommended in most of the applications in order to control temperature of the internal atmosphere. 
         [0024]    The air separation device  11  or  21  can be made using a special hollow fiber membrane or special adsorbents, such as carbon molecular sieve, zeolitic crystals, etc. Other air separation techniques can be used, since all of them would work using a much higher permeability rate of water vapor and carbon dioxide versus oxygen or nitrogen. For instance, carbon dioxide is about ten times faster in permeating a membrane or other obstacle than oxygen and water vapor is even faster than CO2. Nitrogen is about 2.5 times slower than oxygen, which allows retaining most of it for producing hypoxic environments. Therefore, most suitable for this purpose are oxygen-enrichment or nitrogen membranes with modified flow/pressure parameters. Even dryer membranes are suitable for producing hypoxic environments since they will also remove carbon dioxide and some oxygen. 
         [0025]    The embodiment shown on  FIG. 1  can also control oxygen content or even produce normoxic environment. In this case, environment  10  might be not completely airtight and device  16  needs to be adjusted to provide higher ventilation rate. 
         [0026]    The most suitable technology for the device  21  is either a membrane, highly permeable for CO2, or zeolitic crystals that can adsorb CO2 in Pressure Swing Adsorption (PSA) process. Such crystals have tiny holes inside, big enough to allow CO2 molecules to enter under a certain pressure, but are small enough to retain them. When pressure drops, CO2 will be released and vented outside. Such crystals can be made by blending either cobalt or zinc with imidazolates. Device  21  equipped with such zeolitic crystals can also be used for maintaining healthy atmosphere in normoxic and hyperoxic environments as well. For instance, this method can be very beneficial for submarines and underwater structures, aircraft and military vehicles, space vehicles and interplanetary stations. 
         [0027]    One of the biggest benefits of the invented system is its energy efficiency. For instance, a Hypoxic Room System for 5 people exercising at a time would require at least 2000 liters/min of hypoxic air flow and there still might be a problem with rising carbon dioxide level. Such a system, based on a hollow-fiber membrane technology, would require about 35 KW of power. By using the invented method and system the power consumption can be reduced approximately by 50%. 
         [0028]    Energy can be also saved by using this method of carbon dioxide and moisture extraction from hermetic normoxic environments, such as submarines, aircraft, spacecraft, vehicles and other occupied compartments. 
         [0029]    The invented system provides a cost- and energy efficient method of maintaining healthy atmospheres in enclosed occupied spaces.