Abstract:
A valve includes an inlet to allow gas to enter the valve; an overpressure system to provide an overpressure; and a reclaim outlet to allow gas from the valve to exit the valve. Optionally, the reclaim outlet can connect to a reclaim system or a dump system which can be used for recovering the gas flowing through the valve.

Description:
BACKGROUND 
       [0001]    In dry toxic or undesirable atmospheres, for example, in the tunneling and life support industry, workers need a breathing apparatus to ensure that they don&#39;t breathe in the atmosphere. To ensure safety, this breathing apparatus is typically built to have an overpressure. Thus, if a leak were to occur, the overpressure in the helmet would force the gas inside the helmet out and prevent the toxic atmosphere from entering the worker&#39;s helmet. 
         [0002]    In performing operations far underground, workers are often supplied with a mixture of Helium and Oxygen, known as “Heliox” and/or a mixture of Helium, Oxygen and Nitrogen, known as a “Trimix.” These mixtures are provided to the helmets of the workers, and the exhaled gas is let out into the outside surroundings. 
         [0003]    Overpressure helmets are common in the diving industry. Examples of such diving pressure helmets and reclaim valves for diving helmets can be found in DE-A-20 2012 003542, EP-A-2522570, EP-A-1500586, U.S. Pat. No. 4,219,017 and DE-A-21 17392. DE-A-20 2012 003542 specifically discloses an overpressure valve for a diving helmet or diving mask. EP-A-2522570 discloses a regulator valve for a diver. The regulator valve is connected to a reclaim system that can reclaim gas exhaled by the diver. Additionally, the regulator is also connected to an exhaust valve which allows for the exhaust of exhaled gas to the external environment. The exhaust valve is connected to the regulator through a conduit, and for use, the exhaust valve must be opened and a separate shut-off valve for the reclaim conduit must be closed. Thus, a plurality of valves at different locations must be used and properly switched to an open or closed condition (respectively) to change from one exhaust system to the other. 
       SUMMARY 
       [0004]    A valve includes an inlet to allow gas to enter the valve; an overpressure system to provide an overpressure; and a reclaim outlet to allow gas from the valve to exit the valve. 
         [0005]    Such a valve allows for reclaiming of a significant portion of gases from the valve while maintaining an overpressure, allowing for use in environments where overpressure is desired or required. 
         [0006]    According to an embodiment, the valve further comprises a local atmosphere outlet to allow gas from the valve to exit to a local atmosphere; and a switch to control whether gas entering the valve exits through the reclaim outlet or through the local atmosphere outlet. 
         [0007]    The switch and local atmosphere outlet allows the valve to be adaptable and flexible for use in a variety of situations. The ability to easily switch between the local atmosphere outlet and reclaim outlet also provides an element of redundancy in the system, which promotes safety. 
         [0008]    According to an embodiment, the overpressure system comprises a spring. 
         [0009]    According to an embodiment, the switch is activated manually. 
         [0010]    According to an embodiment, the switch is located on an outside of the valve. 
         [0011]    According to an embodiment, the overpressure system provides an overpressure of about 0.5 cm to about 8 cm water height. 
         [0012]    According to an embodiment, the overpressure system provides an overpressure of about 0.6 cm to about 5 cm water height. 
         [0013]    According to an embodiment, the overpressure system provides an overpressure of about 2 cm water height. 
         [0014]    According to an embodiment, the valve further comprises a valve housing. 
         [0015]    According to an embodiment, the valve further comprises a connection portion to connect the valve to a helmet. Optionally, the connection portion comprises threads. 
         [0016]    According to an embodiment, the valve is a part of an overpressure helmet. 
         [0017]    According to an embodiment, the reclaim outlet connects to a reclaim system or a dump system. 
         [0018]    According to a further aspect of the invention, a method of manufacturing a reclaim valve includes forming a valve with an inlet to allow gas to enter the valve and a reclaim outlet to allow gas in the valve to exit the valve; and forming an overpressure system within the valve. 
         [0019]    According to an embodiment, the method further comprises forming a local atmosphere outlet to allow gas from the valve to exit to a local atmosphere; and forming a switch to control whether gas in the valve exits through the reclaim outlet or through the local atmosphere outlet. 
         [0020]    According to an embodiment, the gas exits the reclaim outlet into a reclaim system or into a dump system. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0021]      FIG. 1  schematically illustrates an example overpressure helmet in use. 
           [0022]      FIG. 2 a    shows a front view of a reclaim valve. 
           [0023]      FIG. 2 b    shows a side view of the reclaim valve of  FIG. 2   a.    
           [0024]      FIG. 2 c    shows an exploded view of the reclaim valve of  FIG. 2   a.    
           [0025]      FIG. 2 d    shows a cross-sectional view of the reclaim valve of  FIG. 2   a.    
       
    
    
     DETAILED DESCRIPTION 
       [0026]      FIG. 1  schematically illustrates an example overpressure helmet  10  in use in a pressurized environment  11 , and includes overpressure reclaim valve  12 , first and second supply lines  14 , reclaim line  16  and regulator  18 . Pressurized environment  11  can be, for example, an underground drilling environment. 
         [0027]    First supply line  14  and second supply line  14  connect to overpressure helmet  10  to supply the user with breathable gas through helmet  10 . Overpressure helmet  10  also provides a pressure within helmet  10  higher than the pressure outside helmet, for example, 2 cm water column, to ensure that no gas from pressurized environment  11  enters into helmet  10  if a leak were to occur. In some embodiments, the overpressure can be anywhere from about 0.5 cm to about 8 cm water height, or about 0.6 cm to about 5 cm water height. 
         [0028]    Reclaim line  16  connects to overpressure helmet  10  at overpressure reclaim valve  12 . Overpressure reclaim valve  12  receives exhaled gas from user, and can permit the exhaled gas within valve to exit valve through reclaim line  16  or can permit the exhaled gas within valve  12  to exit overpressure valve  12  to pressurized environment  11 . 
         [0029]    Reclaim line  16  connects to regulator  18 , and then to a reclaim or dump system (not shown) which may be able to filter, clean and/or remix the breathing mixture for the user. This system could be located close to the user at the pressurized environment  11 , or could be located far from the user above ground, where space is more freely available. The system could be a normal reclaim installation or facility, a worker breathing gas reclaim installation or facility, or an outside vent or dump installation or facility. Regulator  18  can be used as a safety measure to step down the pressure from the helmet  10  to the pressure necessary to bring the exhaled gas outside. 
         [0030]      FIG. 2 a    shows a front view of overpressure reclaim valve  12 ,  FIG. 2 b    shows a side view of overpressure reclaim valve  12 ,  FIG. 2 c    shows an exploded view of overpressure reclaim valve  12 , and  FIG. 2 d    shows a cross-sectional view of overpressure reclaim valve  12 . 
         [0031]    Overpressure reclaim valve  12  includes inlet  19 , reclaim outlet  20 , local atmosphere outlet  22 , switch  24 , housing  26 , spring  28  with ball  30 , bushings  32 , exhaust valve  34 , chamber  35 , threaded ring  36 , diaphragm  38 , cover  40  with local atmosphere outlets  22  and clamp valve cover  42  with fastener  44 . Switch  24  components include threaded ring  46 , switch ring  48 , spacer  50 , and socket  52 . Reclaim outlet  20  includes coupling hose  54 , o-ring  56 , valve exhalation  58 , spring  60 , spring seat  62 , circlip  64 , and safety plate  66  with fastener  68 . 
         [0032]    Housing  26  can be a universal type of housing, allowing connection to many different types of helmets  10 . Housing  26  can include a connection portion  25 , which can include threads for connecting to helmet  10 . Switch  24  sits near the inlet  19  of valve  12 , and controls whether gas in valve  12  will exit reclaim outlet  20  or will exit local atmosphere outlet  22 . Switch  24  controls this by allowing for a partial rotation of switch ring  48  using socket  52 . This rotation can be done manually by the user. 
         [0033]    Exhaust valve  34  sits within housing  26 , and controls the pressure in helmet  10  (see  FIG. 1 ) in conjunction with spring  28  and ball  30 . The force on spring  28  controls the extent of overpressure inside helmet  10 . 
         [0034]    During use, exhaust valve  34  can move within housing  26 , allowing exhaled gas entering valve through inlet  19  to flow to chamber  35  when the overpressure is overcome. When switch  24  is set so that gas can exit reclaim outlet  20 , exhaust valve  34  moves upward to allow gas into chamber  35 . Diaphragm  38  is also flexed upwards, and these movements cause other movements, for example, tilt or rotation, in reclaim outlet  20  components, allowing the gas from chamber  35  to flow out reclaim outlet  20 , where it will enter reclaim line  16  (see  FIG. 1 ). 
         [0035]    When switch  24  is set so that gas exits local atmosphere outlet  22 , local atmosphere outlet  22  is aligned with holes in cover  40 . Thus, once exhaled gas enters valve  12  through inlet  19 , the alignment of holes of outlet  22  in switch ring  48  with holes in cover  40  allow gas to exit into the local atmosphere outside of helmet  10 . 
         [0036]    Overpressure reclaim valve  12  allows for gas to be reclaimed in situations where an overpressure is required, such as in dry toxicities or an overpressure atmosphere. Typically, past reclaim valves were only able to work in situations where the pressure inside the helmet is equal to the pressure outside the helmet in the local atmosphere, and would not be able to function properly with or maintain an overpressure in helmet  10 . Gases used in the performance of operations far underground can include expensive mixtures of Helium with Oxygen and sometimes Nitrogen. As Helium is very expensive and difficult to obtain in some parts of the world, the ability to reclaim and reuse the gas can be very valuable. A reclaim system such as the one shown in  FIG. 1 , through the use of overpressure reclaim valve  12 , can result in the saving and reuse of about 60%-90% of gases used during an operation. 
         [0037]    Additionally, the use of overpressure reclaim valve  12  with a gas reclaim system can allow workers to remain at a job site far underground longer. In past systems, workers would have to return to the surface for new breathable gases frequently. As this return often required decompressing, it was very time-consuming. Through the use of overpressure reclaim valve  12  that can maintain an overpressure during operation, gas can be reclaimed, cleaned and reused, eliminating or lessening the need to return to the surface for additional breathable gases. 
         [0038]    Switch  24  of overpressure reclaim valve  12  allows the gas in valve  12  to exit either through reclaim outlet  20  or through local atmosphere outlet  22 , making valve  12  adaptable and safe for use in many different situations. This can allow the user to easily change from one outlet to the other, and can ensure that any malfunction or issues in reclaim system, regulator  18 , or reclaim line  16  would not endanger the user of overpressure helmet  10 . 
         [0039]    By making overpressure reclaim valve  12  compact with a standard outer housing  26 , overpressure reclaim valve  12  can work with standard overpressure helmets currently on the market. This can eliminate the need to replace an entire overpressure helmet  10  when desiring to reclaim gas used. 
         [0040]    While the invention has been described with reference to exemplary embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiments disclosed, but that the invention will include all embodiments falling within the scope of the appended claims.