Abstract:
An improved oral/nasal mask-hood is provided for protection of individuals in the event of fire or smoke exposure. When attached to a supplemental supply of oxygen the mask-hood also provides hypoxia protection to individuals exposed to decompression as in some aircraft incidents. The mask-hood employs a five stage filtering process for converting toxic atmospheric air to breathable fresh air. The hood covers the wearer&#39;s head, neck and shoulder area. A neck seal is provided inside the hood for preventing gases from locating within the hood and irritating the wearer&#39;s eyes. A transparent member is located on the hood adjacent the wearer&#39;s line of sight to provide visibility during the emergency. The hood-mask device, as assembled, is small enough to retrofit into the space provided for the present decompression mask alone.

Description:
This application is a continuation of U.S. application Ser. No. 08/001,339, filed Jan. 7, 1993, now abandoned. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to protection during hypoxia and fire emergencies and more particularly is concerned with a protective hood and oral/nasal mask for providing breathable air during hypoxia and fire emergencies. 
     2. Description of the Prior Art 
     In aircraft fire situations, toxic and noxious gases are typically present in the aircraft. Survivors of recent aircraft fires have stated that one or two breaths of the smoke and noxious gases present in the aircraft fire resulted in the passengers lungs feeling solidified and in the passengers experiencing extreme sleepiness. Passengers of aircraft fires cannot risk taking several breaths of the contaminated, toxic atmospheric air prior to receiving purified air when such immediate and critical symptoms occur from one or two breaths of the noxious and toxic gases. In addition, the noxious gases which are present tend to immediately irritate the passengers eyes, preventing the passenger from seeing and being able to find emergency exits. Also, if the emergency tends to last for an extended period of time, the existent oxygen supplies on the aircraft can be depleted. Many aircraft are equipped with emergency masks for use in case of aircraft decompression. These masks are designed to provide oxygen to air craft occupants very quickly. The present invention combines this hypoxia protection with smoke and fire protection in a single device. The standard hypoxia device provides supplemental oxygen to support respiration but still relies on the aircraft cabin air for additional quantities of air. 
     PCT International Application No. WO 89/00873 to Brookman discloses a small dropout package containing a protective hood for deployment to enclose the head of the passenger to improve the passenger&#39;s vision in the smoke, a protectable breathing mask for enclosing the mouth and nose of the passenger in order to provide breathable air and a dual air supply system. The Brookman device provides a chemical air purifier having a wet scrubbing system for purifying cabin air of contaminants to supply breathable air to the user. 
     Brookman discloses using a wet filtering system. The filtering system of Brookman contains a first chamber which contains a sac to store wet base materials until activated by pulling on an actuator. Once activated, the wet base materials scrub the acid gases, which have entered the first chamber, to neutralize such gases. The neutralized gases are then allowed to passed on through a porous membrane to a second chamber having a catalyst disposed within the second chamber. The porous membrane, however, retains the wet base materials within the first chamber. The wet base materials are released from the sac by the pull of a cord which pulls the sac between a pair of rollers to rupture the sac and displace the wet chemical agent into the first chamber. 
     The use of the wet filtering system taught by the Brookman reference creates several significant disadvantages and problems during operation of such filtering system. The first disadvantage is the mechanical process required to rupture the sac to release the wet chemical agent. The pulling of the sac is achieved by a cord which is attached at both ends. If either end of the cord is inadvertently or accidently disconnected, the sac will not be ruptured and the wet chemical agent will not be released. Thus, the toxic and noxious gases passing in the first chamber will not be neutralized, but sent to the second chamber in their original harmful state. Additionally, as a liquid scrubber will be released in the first chamber upon rupture of the sac, an additional sealing means has to provided at the rollers to prevent leakage of the liquid out of the first chamber. Such leakage would again allow the gases to pass through the first chamber unneutralized. Another problem with the use of liquid scrubber is that during fire emergencies, concerning high temperatures, there will be concerns regarding the boiling points of the liquid used to neutralize the gases. All of these problems with the filtering system of the Brookman create significant safety concerns during real emergencies. Brookman also fails to provide for a heat absorber. Accordingly, the gas which travels through the catalyst can be at a high and harmful temperature and could cause serious injury to the user of such device. 
     PCT International Application No. WO 87/01949 to Stewart discloses a breathing apparatus comprising a face mask attached to but detachable from an oxygen supply tube and connected to an inflatable reservoir or bag held in a deflated rolled up condition but releasable to provide when attached and deflated, an oxygen supply system and, when detached and inflated a portable respirator or ventilator in a closed rebreathing system with rebreathing bag and oxygen supply in a microclimate free from noxious or hot gases. 
     Atmospheric air is prevented from entering the Stewart device, as the Stewart device is merely connected to an oxygen supply. Another disadvantage of Stewart, is the hood fails to provide a protective neck seal, as the reference discloses providing goggles to protect the eyes from noxious gases and very hot air. 
     Brookman and Stewart both fail to disclose a desiccant material for eliminating fogging which could affect the user&#39;s visibility. In Stewart, the exhaled air passes through a carbon dioxide absorber and inflates the reservoir which becomes a rebreathing bag. The carbon dioxide absorber, extends the time for which rebreathing can take place without dangerous build of carbon dioxide. The carbon dioxide absorber does not acts as an anti-fogging device. In fact, the carbon absorber operates regardless of whether the Stewart device is utilized with a hood or not and is, thus, not attached to the hood. 
     U.S. Pat. No. 4,583,535 issued to Saffo discloses a protection mask comprising a flexible hood having a head opening for placing said hood over the head of a wearer. The hood is provided with an elastic band sewn to the head opening to close the hood relatively tightly around the user&#39;s neck. 
     One disadvantage of Saffo, is the engagement of a non-elastic or elastic neck seal is not simply solved with the contact of the neck seal material to the neck. The elastic material must effectively seal long hair, facial hair, decorative apparel for the hair and the neck, and the overall range of anthropometric neck sizes. 
     The present invention replaces the standard hypoxia device by providing improved hypoxia protection, by filtering the additional cabin air required in a decompression event, and the unique feature of smoke and fire protection by providing (with or without a supply of supplemental oxygen) filtered cabin air in the event of an aircraft fire. Therefore, there exists a need for a dual air supply system providing the user or passenger with either, or both, fresh air from the local supply aircraft&#39;s emergency air source, if provided, or from the contaminated surroundings by filtering the air to remove the toxic gases before reaching the passenger. There also exists a need for a device which can rely entirely upon the ambient air supply to revive the user or passenger with fresh, breathable air from contaminated surrounding air for a temporary period sufficient to escape from the room, the surrounding area or the cabin of an aircraft. 
     In summary, there exists a need for an aircraft respiratory system incorporating both an oral/nasal mask providing the passenger with fresh, breathable air and a protective hood to protect the passenger from the smoke and noxious gases associated with an aircraft fire for improved passenger visibility. There also exists a need for the air purifier to continue to work after the user detaches himself from the bottled air or the aircraft&#39;s emergency air in order to exit the area, room or aircraft. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide an air purifying system that allows the user to breath air from an existing air supply and/or from surrounding atmospheric air. 
     It is another object of the present invention to provide a protective hood to improve passengers&#39; visibility for an escape during hypoxia and fire emergencies. 
     It is yet another object of the present invention to provide an oral mask and smoke hood combination which is compact and can be stored in an overhead passenger service unit of an aircraft which drops down from the service unit during an emergency. These and other objects are provided by an oral/nasal mask and hood combination. 
     Where provided, the mask is removably attachable to a standard oxygen supply, such as an existing oxygen supply on an aircraft overhead compartment. On aircraft without installed supplemental oxygen systems the unit may be attached to a portable oxygen supply or used without attachment to an oxygen source. The instant invention may be used for smoke and fire protection in non-aircraft environments. The mask contains a five stage filter system to allow the user to breath atmospheric air during an onboard fire or hypoxia emergency, and that protection continues after the mask is detached from the aircraft oxygen supply. Fires on aircraft can produce various products of combustion including CO, CO2, acid gases, cyanide, heat and smoke. An effective mask must reduce many of these products to tolerable levels. In the instant invention, many of these products are removed through a five stage filter. The first removes particulate smoke. 
     In the second stage of the filtering process, a plurality of zeolite spheres are provided for the filtering out of some toxic gases. The third stage consists of an activated charcoal carbon for the filtering out of many of the remaining gases. At this point most products of combustion would be removed, except for CO and CO2. 
     The fourth stage consists of a catalyst for converting carbon monoxide to carbon dioxide. This conversion significantly increases the temperature of the gas. Thus, the fifth and final stage of the filtering process consists of a heat absorber for reducing the temperature of the now breathable air to tolerable levels before reaching the user. 
     A hood is attached to the mask. When not in use the hood is folded compactly around filter portion of the oral/nasal mask and held in place by a retainer. A deployment strap, attached to the hood, is pulled to break the retainer when the hood is needed to be donned. The hood fits over the wearer&#39;s head, neck and shoulder area. An elastic neck seal is attached to the inside of the hood to provide a tight fit around the wearer&#39;s neck and to prevent smoke from reaching and irritating the wearer&#39;s eyes. A transparent lens, to provide visibility to the wearer during an emergency, is provided on the hood adjacent to the wearer&#39;s line of sight. 
     In accordance with these and other objects which will be apparent hereafter, the instant invention will now be described with particular reference to the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DETAILED DRAWINGS 
     In the drawings: 
     FIG. 1 is a perspective view of the oral/nasal mask. 
     FIG. 2 is a side view of the oral/nasal mask. 
     FIG. 3 is a perspective view of the oral/nasal mask-hood in use before deployment of the hood. 
     FIG. 4 is a perspective view of the oral/nasal mask-hood, attached to an existing oxygen supply, in use with the hood deployed. 
     FIG. 5 is a quarter-cross section of the oral/nasal mask-hood before deployment of the hood. 
     FIG. 6 is a quarter-cross section of the oral/nasal mask-hood after deployment of the hood. 
     FIG. 7 is a perspective view of the oral/nasal mask-hood stored in an overhead compartment of an aircraft. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     An oral/nasal mask  22  of the protective hood/mask device  20  of the present invention is shown in FIGS. 1 and 2. Mask  22  has a mask inlet  32  and a mask outlet  34 . Preferably, mask inlet is cylindrically shaped. Mask outlet  34  has an aperture shaped to conform to the wearer&#39;s nose and cheek region. Mask  22  also has a plurality of internal threads  25  at its mask inlet  32 . An exhalation aperture  27  is located or disposed on one side of mask  22 . Surface  29  at mask outlet  34  rests against the wearer&#39;s nose and cheek region to further prevent toxic gases from entering mask  22 . 
     As seen in FIG. 3, mask  22  is shown in operation. Mask  22  is retained against the user&#39;s nose and cheek region by strap  23 . Preferably, strap  23  is made of an elastic material. However, it is to be understood that any material which will retain mask  22  tightly around the user&#39;s nose and cheek region can be utilized for strap  23 . A purifying assembly  66  is shown attached to mask  22 . Purifying assembly  66  includes a first housing  68  and a second housing  70 . Preferably housings  68  and  70  are cylindrically shaped to provide a better efficiency for assembly  66  since air flow is cylindrical. Second housing  70  contains a plurality of external threads cooperating with the internal threads  25  of mask  22 . First housing  68  contains a first flange member  106  and a second flange member  108 . Flanges  106  and  108  thereby form a flange recess  110 . As seen in FIG. 3, a smoke hood  36  is folded compactly around the circumference of first housing  68  within flange recess  110  between flange members  106  and  108  and also retained within hood retainer  46 . Attached to smoke hood  36  is at least one deployment strap  48  for pulling smoke hood  36  from its folded position. Straps  48  are pulled in the direction of the arrows A and B. 
     FIG. 4 illustrates the protective hood/mask device  20  in operation. As in FIG. 3, mask  22  is shown positioned tightly around the user&#39;s nose and cheek area and retained by strap  23 . A first end of first housing  68  is shown attached to a reservoir bag  50  which in turn is connected to air tube  60 . Sized elastic rings  113  removably attach reservoir bag  50  to first housing  68 . A reservoir valve assembly  52  is attached to reservoir bag  50 . Reservoir valve assembly  52  includes a reservoir valve  54  fitted to reservoir bag  50  which opens under reduced internal pressure and makes possible the inhalation of ambient air if the wearer&#39;s breathing demand exceeds available oxygen volumes as supplied by the existing oxygen supply. Reservoir valve  54  is protected by reservoir protection cage  56  to assure a clear inhalation path for the ambient air. Once inside reservoir bag  50 , the ambient air flows through purifying assembly  66  to provide the wearer with breathable air. Air tube  60  can be attached to an existing oxygen supply (not shown). Oxygen from the existing oxygen supply flows through air tube  60 , reservoir bag  50 , purifying assembly  66  and mask  22  to the wearer. Hood  36  is provided with a toroidal, elastic neck seal  112  sealed to the interior of hood  36  at  116  with a transition of the material to the opening for the head. Neck seal  112  is adjacent to a substantial portion of the user&#39;s neck area. Neck seal  112  is kept tightly around the user&#39;s neck area by elastic strip  114 . Neck seal  112  has an aperture in which the user inserts his or her head through. Transparent lens  40  is sealed to the interior edge of an aperture in smoke hood  36  to provide visibility to the user during an emergency. Transparent lens  40  can be chemically treated for anti-fogging and abrasion resistance. Protective hood  36  and transparent lens  40  provide protection from direct flame, radiant heat and chemicals. As seen in FIG. 4, smoke hood  36  covers the user&#39;s head, neck and shoulder areas. Neck seal  112  prevents any outside air from locating within hood  36 . Thus neck seal  112  prevents the gases from irritating the wearer&#39;s eyes. 
     As seen in FIG. 5, a quarter cross-section of hood/mask device  20  is shown. Mask  22  includes an exhalation valve assembly  24 . Exhalation valve assembly  24  consists of an exhalation valve  26  for expired air and exhalation valve protective cage  28 . Protective case  28  assures a clear path for the exhalations. Hood  36  is shown folded compactly between flange members  106  and  108 . Hood  36  is retained folded by a thin heat shrink material  44  perforated for ease of deployment. Also attached to hood  36  are deployment straps  48  for breaking heat shrink material  44  and allowing hood  36  to unfold and be fitted and cover the head, hair, neck and shoulders of the wearer. 
     In addition to housings  68  and  70 , purifying assembly  66  consists of a number of components located within housings  68  and  70 . Located within housing  70  is a heat absorber  96 . Preferably, heat absorber is molded into a cylindrical configuration similar to housing  70 . Heat absorber can be any material which reduces the temperature of the gases flowing through housing  70  before they reach the wearer. Heat absorber  96  consists of microencapsulated phase change materials which reduce the temperature of inhaled gases to a limit below that of human skin or tissue damage. Heat absorber  96  has a plurality of external threads  100  for mating with internal threads  74  of housing  70 . Threads  100  and  74  prevent sidewall channeling of the gases through housing  70 . Threads  74  and  100  create a turbulence path along the sides of heat absorber  96  to prevent gases from flowing through. Thus, this unique mating method protects the wearer from breathing gases of high temperatures which would have traveled through housing  70  without going through heat absorber  96 . Filters  84  and  86  are provided at each end of heat absorber  96 . Filters  84  and  86  retain filtration media that are present at each end of heat absorber  96 . A snap ring  78  is provided at the second end of housing  70  to maintain a tight fit for filters  84  and  86  with heat absorber  96 . 
     Located within housing  68  is a three stage air purifier. A filter  82  and inlet screen  88  are present at the first end of housing  68 . In the second stage, a plurality of zeolite molecular sieves in the form of spheres or one piece monolith  90  are provided in an internal ridged surface section  73  of housing  68 . Ridges  73  eliminate sidewall gas channeling along the interface between housing and zeolite structures  90 . Zeolite material filters out some of the combustion products flowing into housing  68  such as acid gases and water vapor. 
     In the third stage, an immobilized activated carbon monolith  92  is provided. Preferably, activated carbon  92  is cylindrically shaped similar to housing  68 . Activated carbon  92  contains a plurality of external threads  98  for mating with internal threads  72  of housing  68 . Threads  72  and  98  prevent sidewall channeling of the gases through housing  68  by creating a turbulence path along the sides activated carbon  92  to prevent gases from flowing through. Thus, this mating method protects the wearer from breathing toxic and noxious gases which would have traveled through housing  68  without going through activated carbon  92 . Activated carbon  92  can be comprised of an activated charcoal consisting of irregular shaped immobilized grains. The grains are impregnated with copper, silver and chromium for holding back and filtering gases which were able to pass through zeolite spheres  90  namely, hydrocarbons, water vapor, hydrogen bromide, hydrogen fluoride, hydrogen chloride, hydrogen cyanide, sulphur dioxide, oxides of nitrogen, acrolein and ammonia. After the gas has been filtered through activated carbon  92  the only combustion products remaining in abundance are CO and heat. 
     In its fourth stage, a catalyst  94 , typically a noble metal monolith, is provided for oxidizing the toxic carbon monoxide gas to carbon dioxide. This conversion of the gas also increases the temperature of the gas. Preferably, catalyst  94  is cylindrically shaped similar to housing  68 . Catalyst  94  can be either formed from a mixture of transition metal oxides commonly known as hopcalite or result from the coating or plating of elements from the platinum metal group on a ceramic substrate. Catalyst  94  snaps into housing  68  between first housing internal thread  71  and first housing internal flange  107 . This snap-in construction prevents side wall channeling of the toxic carbon monoxide out of first housing  68  and into second housing  70 . A filter retainer  80  and snap ring  76  are provided at the first end of housing  68  to maintain a tight fit between filter  82 , screen  88 , spheres  90 , activated carbon  92  and catalyst  94 . In addition spheres  90  are tightly retained between screen  88  and activated carbon  92 . After the gas has been converted to carbon dioxide it travels to second housing  70  to heat absorber  96  which reduces the temperature of the gas as described above. 
     Housings  68  and  70  are attached to each other by snap lock  102 . Housing  70  contains a recess  105 . A sealing ring  104  is provided and located within recess  105  to prevent gases from channeling through the area where housings  68  and  70  meet and thus avoiding the filtering stages. As seen in FIG. 6, smoke hood  36  is shown deployed (Deployment straps  48  have been pulled and heat shrink material  44  has been broken). Smoke hood  36  remains retained within hood retainer  46 . Thin layers of anti-fogging desiccant material  42  are attached to the interior surface of hood  36  immediately adjacent to mask exhalation valve  26 . Therefore the expired air traveling through valve  26  contacts desiccant material  42  which prevents the air from fogging transparent lens  40 . Neck seal  112  in conjunction with hood  36  define a closed space which is inflated by the wearer&#39;s exhalations. Therefore, the inflated hood enhances thermal protection and creates a cushion for the wearer&#39;s head in the case of falling objects hitting hood  36 . In addition, the confined exhalations provide a secondary source of breathable gas for penultimate escape efforts in fire emergencies. 
     As seen in FIG. 7, the protective hood/mask device  20  is shown stored in its initial compact position within storage compartment  122 . Smoke hood  36  is folded around the circumference of first housing  68 . Smoke hood  36  is constructed of a non-flammable, gas impermeable material. Reservoir bag  50  is folded into a compact position next to device  20 . Air tube  60  is shown attached at one end to reservoir bag  50  and at its other end to existing oxygen supply  120 . Device  20  can be stored in a container  124  to protect device  20  from the containments located within compartment  122 . 
     While the instant invention has been described in what is considered to be the preferred embodiment, it is to be understood that these descriptions are given by means of example only, and not by means of limitation. It is to be understood that changes and modifications may be made to the description given and still be within the scope of the invention. Additionally, the instant invention is not limited to aircraft emergency, but can be used in fire and hypoxia emergencies occurring in other situations as well. Further, it is clear that obvious changes and modifications will occur to those skilled in the art.