Abstract:
A rebreathing apparatus has a clothing article wearable on a person. The clothing article defines a channel configured to be fluidly connected to at least one tube. The tube is configured to be fluidly connected to a mouthpiece. When the person exhales, the exhaled breath enters one end of the channel and passes through the channel while being scrubbed of CO 2 . When the user inhales, the scrubbed air is drawn from the channel.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention related to a closed circuit rebreather wherein the carbon dioxide (CO 2 ) scrubbing material is imbedded within a body worn vest in order to minimize the profile of the rebreather as well as to use the natural breathing rhythm of the user to assist in the function of the rebreather. 
     2. Background of the Prior Art 
     Rebreathers are used in a wide variety of applications including military settings, especially underwater teams that desire to remain stealth and not have air bubbles surface as would be the case if using open circuit breathing apparatus. Other applications include mine rescue or other industries where poisonous gas may be present or oxygen absent, manned space vehicles and space suits where a person is effectively in a vacuum, hospital anesthesia breathing systems that supply appropriately proportioned gas mixtures to a patient without letting the gas escape to be breathed by hospital personnel, submarines, and oxygen hyperbaric chambers, among other applications. 
     The rebreather works by recirculating exhaled air from the user&#39;s breath based on the fact that a person only absorbs about 25 percent of the available oxygen with each breath. The exhaled air passes through a scrubbing material, such as soda lime, wherein the carbon dioxide is removed. Additional oxygen and/or a diluent is added to the circuit either manually or via an electronic system that senses for the oxygen concentration using appropriate sensors such as oxygen sensitive electro-galvanic fuels cells that calculate the oxygen concentration in the breathing loop. The scrubbing material is held within a canister that is worn about the body of the person. The breathing air within the loop moves into and out of the canister through the small pressure changes generated through respiration by the user. While extremely useful, current rebreathers suffer from certain limitations. The large mounted scrubbing canister is cumbersome to wear and throws the overall weight distribution of the wearer far off from ideal. A land-based user finds such large canisters and the uneven weight distribution occasioned by the canisters to impede maneuverability and increase overall fatigue. Water-based users find that the canisters change the natural contours of the body so as to make the user less hydrodynamic via increased drag which decreases swimming speed and also increases fatigue. If the underwater user is scooter-based, the increased profile provided by current rebreathers increases overall drag which decreases scooter performance and decreases battery life. If a water-based user transitions to land, the uneven weight loading provided by the rebreather makes the transition awkward at best. Additionally, the diver is subject to hydrostatic loads due to the extra force required to breathe into a counter-lung above or exhale into a volume below the diver&#39;s chest. 
     What is needed is a rebreather that addresses the above-mentioned shortcoming in the art by providing a closed circuit rebreathing system that does not rely on a large carbon dioxide scrubbing canister that affects the natural contours of the user and that does not greatly alter the overall weight distribution load upon the wearer. Such a rebreather should allow the counter-lungs used by a rebreather to be essentially at chest level in order to permit the user to breath without the need to exert substantial additional breathing pressure. Ideally, such a rebreather will be of relatively simple design and construction and be easy to use and maintain. 
     SUMMARY OF THE INVENTION 
     The rebreather vest of the present invention addresses the aforementioned needs in the art by providing a closed circuit rebreathing system that, when donned, generally maintains the natural low profile contours of the wearer so as to allow the person to maintain a high level of hydrodynamics when under water so as to allow the person to be able to achieve essentially maximum velocity while swimming without undue fatigue or to minimize drag if using a scooter so as to maintain maximum performance of the scooter without shortening battery life to any great extent. The rebreather vest distributes the weight essentially evenly about the torso of the wearer so as to make the weight distribution more natural in order to allow the user to be more maneuverable on land as well as when transitioning from water to land. The rebreather vest provides its counter lungs at torso level so as to reduce the respiration pressures that must be maintained by the user so as to minimize fatigue. The rebreather vest is of relatively simple design and construction being made using standard manufacturing techniques. The rebreather vest is designed so that it can be stored in a partial vacuum until the device is needed so as to minimize size and storage requirements. 
     The rebreather vest of the present invention uses a counter-lung design that allows a flow path both above and below the arm of the wearer via the flow path of least resistance. The rebreather vest employs the use of a flexible carbon dioxide removal system deployed around the torso. The rebreather vest encapsulates a miniaturized high-pressure gas source within the counter-lung and may use the form of a single-use rebreather. 
     The rebreather vest of the present invention is comprised of a human-torso-wearing configured vest that has a first front portion and a second front portion joined by a back portion such that an internal air tight cavity exists within the vest. The cavity is divided into a series of passageways that form a single continuous channel that passes from the first front portion through the back portion and to the second front portion. The channel has a commencement point and a termination point. The cavity may be bounded by an inner layer and an outer layer. A first inlet port is located on the first front portion of the vest at the channel commencement point while an outlet port is located on the second front portion of the vest at the channel termination point. A tube has a first end connected to the first inlet port and an opposing second end attached to the outlet port and also has an opening disposed along its length. A first check valve is disposed within the tube between the opening and the first inlet port while a second check valve is disposed within the tube between the opening and the outlet port. A carbon dioxide scrubbing material is removably disposed throughout the length of the channel. A mouthpiece, such as a T-bit mouthpiece, may be located at the opening. A second inlet port is located on the vest such that a first canister having oxygen or diluent therein is fluid flow connected to the second inlet port. A control valve may be fluid flow connected with the first canister and the internal cavity while an oxygen sensor is disposed within the internal cavity and a processing module is provided for controlling the control valve based on at least one reading provided by the oxygen sensor. The first canister may be encapsulated within the second front portion and deliver its gas through a demand regulator system. A third inlet port may be located on the vest such that a second canister having oxygen or diluent therein is fluid flow connected to the third inlet port. An anti-collapse coil maybe disposed within the internal cavity. At least one over-pressure valve is attached to an outer surface of the vest and is in fluid flow communication with the internal cavity. Mounting studs may extend outwardly from the vest. A divider having a first surface and an opposing second surface may be disposed within the internal cavity between the inner layer and the outer layer such that a first portion of the channel is disposed between the first surface of the divider and the inner layer and a second portion of the channel disposed between the second surface of the divider and the outer layer. Neither the first portion of the channel nor the second portion of the channel is necessarily contiguous. A plurality of generally V-shaped resilient spacers may each be attached to either the inner layer or to the outer layer and face toward the divider. Alternately, a plurality of ribs is provided such that each rib is attached to the first surface of the divider and to the second surface of the divider. The scrubbing material may be disposed within the channel in a first layer and an overlapping second layer separated by a fibered filter material based spacer. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1   a  is a front elevation view of the rebreather vest of the present invention in a single layer demand and/or constant flow gas injection configuration. 
         FIG. 1   b  is a back elevation view of the rebreather vest of  FIG. 1   a.    
         FIG. 2  is a front elevation view of the rebreather vest in a double layer demand and electronic control gas injection configuration. 
         FIG. 3  is a back elevation of the rebreather vest of  FIG. 2 . 
         FIG. 4  is a perspective view of the rebreather vest of  FIG. 2   
         FIG. 5  is a partial cross-section view of the rebreather vest of  FIG. 2 . 
         FIG. 6  is a perspective sectioned view of a portion of the internal channels within the rebreather vest of  FIG. 2 . 
         FIG. 7  is an end view of the rebreather vest of  FIG. 5 . 
         FIGS. 8 and 9  are perspective views of other shapes possible for extruded carbon-dioxide absorbent material for use within the internal cavity of the rebreather vest. 
     
    
    
     Similar reference numerals refer to similar parts throughout the several views of the drawings. 
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring now to the drawings, it is seen that the rebreather vest of the present invention, generally denoted by reference numeral  10 , is comprised of a vest  12  of typical human torso configured vest configuration having a front left portion  14  that serves as a first counter-lung, a front right portion  16  that serves as a second counter-lung joined by a back portion  18 . Webbing  20  may be used to join the back portion  18  with the ends of the front portions  14  and  16  or the back portion  18  may be full. Appropriate closure mechanisms (zipper, snap, latches, etc.,—none illustrated)—can be used to close the front of the vest  12  in the usual way. 
     In the embodiment illustrated in  FIG. 1   a , the vest  10  has a first front closure edge, right closure edge or right closure segment extending substantially parallel to, and adjacent to, the zipper at opening  38 . Likewise, the vest  10  has a second front closure edge, left closure edge or left closure segment shown, in  FIG. 1   a , opposite of such right closure segment. As illustrated in  FIG. 1   a , the vest  10  has a perimeter edge extending along the perimeter of the vest. The perimeter edge includes the right closure segment, left closure segment and bottom segment. The perimeter edge defines the neck receiving opening when the right closure segment is in contact with the left closure segment. The vest  10  has a right arm receiving edge which, in the embodiment illustrated in  FIG. 4 , is located to the right of the outlet port  44 . The vest  10  has a left arm receiving edge which, in the embodiment illustrated in  FIG. 4 , is located to the left of the outlet port  42 . 
     The vest  12  is formed from an inner layer  22  that contacts the user&#39;s body and an outer layer  24  joined together in order to provide an air tight internal cavity  26  within the vest  12 . In the embodiment illustrated in  FIG. 4 , a plurality of seals join the layers  22  and  24  together. A first seal extends along the perimeter edge described above. A second seal extends along the right arm receiving edge described above. A third seal extends along the left arm receiving edge described above. 
     The inner layer  22  is made from an appropriate material for body contact which material allows for body hugging as well as stretching. Thin neoprene and Lycra are two suitable materials, although other candidates are also possible. The outer layer  24  may be the same as the inner layer and may have an additional layer  28  thereon that provides additional functionality to the vest  12  such as a ballistic material (KEVLAR etc.,) or may have pockets (not illustrated) into which appropriate body armor may be disposed. If a breathable material is used for either layer  22  and  24 , an appropriate layer will be added in order to achieve the air tight internal cavity  26 . The internal cavity  26  is segregated into a series of passages  30  by a series of walls  32 , made from an appropriate sturdy material such as flexible plastic that is attached to the inner layer  22  and the outer layer  24 . The passages  30  form a single overall continuous channel Removably attached to the inner layer  22  or outer layer  24  or both layers  22  and  24  is an appropriate carbon dioxide scrubbing material  34  such as soda lime, etc. The scrubbing material  34  is to be disposed on a separate backing material  36  (a so-called scrubbing material belt) so as to allow the scrubbing material  34  to be able to be quickly and easily removed and replaced when fully spent. An opening  38 , such as the illustrated zipper (other candidates include cooperating hook and loop material, snaps, etc.,) is provided in order to have service access to the internal cavity  26 —the opening  38  can be located at any appropriate location about the vest  12 . An appropriate seal (not illustrated) is located beyond the opening  38  in order to maintain the air tightness of the internal cavity  26 . Also disposed within the internal cavity  26  is a pair of oxygen compatible anti-collapse coils  40  that help maintain the internal cavity  26  in an “open” configuration when the device  10  is being used. 
     As seen a first or inlet port  42  is attached to the left portion  14  of the vest  12  and air flow communicates with the channel  30 , the channel  30  having its commencement point hereat. A second or outlet port  44  is attached to the right portion  16  of the vest  12  and air flow communicates with the channel  30 , the channel  30  having its termination point hereat. A tube  46  has a first end attached to the inlet port  42  and a second end attached to the outlet port  44 . A mouthpiece  48 , such as the illustrated T-bit mouthpiece is disposed centrally along the length of the tube  46 . It is expressly recognized that a face shield or a full head mask can be used in lieu of or in addition to the mouthpiece  48  depending on the specific application desired for the rebreather  10  as is well understood in the art. A first check valve  50  is located within the tube  46  between the mouthpiece  48  and the inlet port  42  while a second check valve  52  is located within the tube  46  between the mouthpiece  48  and the outlet port  44 . A second inlet port  54  is provided and is fluid flow connected to a first canister  56  having a first valve  58  thereon, via a first air hose  60 , the first canister  56  having oxygen or diluent therein. 
     As best seen in  FIGS. 2-4 , the first canister  56  may also be connected via a second air hose  62  to a control valve  64 , advantageously located on the back portion  18 , the control valve  64  fluid flow connecting the second hose  62  with the internal cavity  26 . One or more oxygen sensors  66  are located on the back portion  18  within a pocket of the vest  12  and sense oxygen levels within the channel  30 . The oxygen sensors  66  are electronically connected to a processing module  68  which module  68  is also connected to the control valve  64  for controlling operation of the control valve  64  based on the readings of the sensors  66 . An appropriate display device  70  is connected to the processing module  68  in order to allow the user to monitor the status of the processing module  68 . As also seen, a third inlet port  72  may be provided and be fluid flow connected to a second canister  74  having a second valve  76  thereon, via a third air hose  78 , the second canister  74  having oxygen or diluent therein. In a two canister configuration, typically the first canister  56  has oxygen therein while the second canister  74  has diluent therein 
     As seen, the internal cavity  26  may be separated into two sections via a semi-rigid (sufficiently rigid to hold its shape, yet sufficiently flexible for vest  12  donning and doffing) divider  80  that extends essentially throughout the internal cavity  26  so that one section of the internal cavity  26  is located between the divider  80  and the inner layer  22  of the vest  12  and the other section is located between the divider  80  and the outer layer  24  of the vest  12 . The scrubbing material  34  is disposed on both sides of the divider  80 . In this configuration, the channel  30  is still a single continuous channel with its commencement point at the first inlet port  42  and its termination point at the outlet port  44 , but now passes through both sections of the internal cavity  26 . In this configuration, the air A passes across substantially more scrubbing material  34  allowing for longer dwell times with the scrubbing material  34  allowing more effective scrubbing of the air A as well as a longer life span between scrubbing material  34  change out. 
     In this dual section configuration, the vest  12  is maintained in the “open” position by a series of separators  82  that are attached to the inner layer  22  of the vest  12  as well as the outer layer  24  of the vest  12 . The separators  82  are made from an appropriate resilient material such as a flexible non-reactive plastic. When the device  10  is not being used, the vest  12  may be held flat, that is the outer layer  24  and the inner layer  22  are pressed tight together which causes the separators  82  to flatten out thereby maintaining the vest  12  is a very flat and compact configuration that is easily stored and transported. The vest  12  may be held in this very flat configuration via an appropriate mechanical means or may be stored under at least partial vacuum to so maintain the vest  12 . When the vest  12  is ready for use, either release of the vest  12  from its mechanical or vacuum hold allows the separators  82  to resiliently spring back to their original V-shape or introduction of air A into the internal cavity  26  achieves the result, thereby filling the vest  12  out. In this configuration, the separators  82  act as valves or flow restrictors for the air A passing thereby. This creates turbulence within the channel  30  which increases the interaction time between the air A and the scrubber material  34  so as to achieve greater efficiency in air scrubbing. 
     As also seen, a series of mounting ribs  84  may be provided and have mounting studs  86  thereon to hold auxiliary equipment E as desired. 
     As seen in  FIGS. 7-9 , an alternate method of separating the layers of the internal cavity  26  uses a divider  80 ′ that has a series of spacer ribs  88  of any appropriate configuration (see  FIGS. 8 and 9 ) on either side, either formed as part of the divider  80 ′ or attached thereto. In this configuration, once a belt of scrubber material  34  is attached to or positioned upon the spacer ribs  88 , a spacer  90  may be placed on the scrubber material  34 , such spacer  90  being a fiber air filter type of material, with a second belt of scrubber material  34  placed onto the spacer  90  in order to further increase the amount of scrubber material  34  within the internal cavity  26 . 
     If water should enter the internal cavity  26  in any fashion, then either a desiccant (not illustrated) can be disposed within the internal; cavity  26  or one or more dump/over-pressure valves  92  can be located on the vest  12  at substantially the lowest point on the vest  12  in order to dispel any water entrained within the internal cavity  26 . 
     In order to use the rebreather vest  10  of the present invention, the channel  30  is populated with the scrubbing material  34  while a fresh first canister  56  is attached to the first hose  60  and second hose  62  if so configured, and a fresh second canister  74  is attached to the third hose  78 . The user dons the vest  12  is the typical way and places the mouthpiece  48  into his or her mouth. The user breathes in normal fashion in the same manner as with other rebreathers. As the person exhales, the exhaled air A is passed through the mouthpiece  48  and enters the inlet port  42  via the tube  46 , the second check valve  52  preventing the air A from flowing toward the outlet port  44 . The air enters the channel  30  within the vest  12  and travels the length of the channel  30  through the front left portion  14 , through the back portion  18 , and into the front right portion  16 . While within the channel  30 , the air A is scrubbed via the scrubbing material  34  in the usual way. Once the air A has reached the end of the channel  30 , the air A enters the tube  46 , scrubbed of carbon dioxide, via the outlet port  44  and is breathed in by the user. During breath intake in, the user cannot draw air A from the inlet port  42  due to the first check valve  50 . By having the relatively heavy scrubbing material  34  distributed about the vest  12 , both front and back, the overall weight distribution of the rebreather  10  for the wearer is relatively well distributed and helps the user maintain balance as humans work exceedingly well whenever a load is essentially evenly placed on the user&#39;s torso. Additionally, both counter-lungs are at torso level making breathing more natural and less labored so as to reduce user fatigue during device  10  usage. Variations employ constant flow oxygen or gas mixture injection as in a semi-closed set plus conventional demand regulator gas delivery during high work output. The constant flow plus demand regulation system allows for positive pressure masks on the wearer. Land based use in contaminated atmospheres is greatly enhanced by this feature. When needed, oxygen, either pure or via a diluent, can be manually replenished into the channel  30  via the first canister  56  simply by opening the valve  58  thereon and letting the oxygen or diluent flow into the channel  30  via the second inlet port  54  or via the second canister  74  by opening the second valve  76  and letting the oxygen or diluent flow into the channel via the third inlet port  72 . Alternately, if the rebreather  10  is electronically equipped, then oxygen or diluent is introduced into the channel  30  automatically via the control valve  62  via the readings of the oxygen sensors  66  and under the control of the processing module  68 . Of course the automatic replenishment system can be manually overridden if the user so desires. When the scrubbing material  34  is fully spent, the material  34  is removed and replenished via the opening  38  provided. 
     While the invention has been particularly shown and described with reference to embodiments thereof, it will be appreciated by those skilled in the art that various changes in form and detail may be made without departing from the spirit and scope of the invention.