Abstract:
An embodiment of a submersible warming garment comprises a closed fluid loop including a warming conduit disposed in thermal communication with a chamber containing a catalyst and a cooling conduit disposed within a wearable garment. A pump moves the fluid through the warming conduit, where heat is gained, to the cooling conduit, where heat is surrendered to a human wearing the garment, and back to the pump. An actuated valve on a container of fuel and an actuated valve on a container of oxygen are controlled using a controller to provide a combustible mixture into the chamber where the mixture reacts in the presence of a catalytic member to generate heat and combustion by-products. The combustion by-products, including carbon dioxide and water, are one of adsorbed and absorbed by a carbon dioxide scrubber and a reusable water storage medium. A fan moves the by-products into the scrubber and water storage medium.

Description:
STATEMENT OF RELATED APPLICATIONS 
       [0001]    This application depends from and claims priority to PCT/US2015/055948 entitled Submersible Warming Device filed on Oct. 16, 2015, which depends from and claims priority to U.S. Provisional Application No. 62/065,111 filed on Oct. 17, 2014. 
     
    
     BACKGROUND 
       [0002]    Field of the Invention 
         [0003]    The present invention relates to a body-warming apparatus for use by a user such as, for example, a diver to maintain body heat during submersion. The portion of the apparatus that provides heat to the user is a heated garment or article worn by or secured to the user. The remaining portion is carried by the user along with other gear. 
         [0004]    Background of the Related Art 
         [0005]    A diver can remain submerged in water only for as long as he can maintain sufficient body heat to prevent hypothermia. The inability to maintain sufficient body heat can result in shivering, hypertension, tachycardia, tachypnea, vasoconstriction, mental confusion, diuresis and hepatic dysfunction. Severe hypothermia can result in a faltering heart rate, respiratory rate and low blood pressure and even death. 
         [0006]    A submerged diver loses heat to the surroundings much more quickly than heat is lost in cold air. A water temperature of 10° C. (50° F.) can result in death in as little as one hour, and can impair motor skills in just minutes without proper maintenance of body heat. 
         [0007]    One drawback to the use of conventional body warmers is the production of bubbles. A diver may wish to remain undetectable during a dive, and this is difficult when bubbles are being generated by the diver&#39;s equipment and released into the surrounding water. The bubbles migrate to the surface where they can be seen by observers on or at the surface of the water. 
         [0008]    Other hostile environments that may require equipment to maintain body heat include environments in which a user is “submerged” in corrosive, poisonous or combustible gas mixtures, or very cold environments that will not tolerate or support an open combustion system. For example, but not by way of limitation, cold gas environs, within a gas storage facility or tank, the vicinity of natural gas or liquefied gas storage or processing tanks or in some areas of a liquefied natural gas tanker. It will be understood that the term “user,” as that term is used herein, may refer to a diver or it may refer to a person that is or will be exposed to environmental conditions in which the body&#39;s natural ability to regulate the body temperature is insufficient and in need of supplemental heat for personnel safety. 
       BRIEF SUMMARY 
       [0009]    In one embodiment, the present invention provides an apparatus that can provide heat to a submerged diver without releasing bubbles that can be seen by observers at the surface. In one embodiment, the present invention provides an apparatus that can provide heat to a user that is exposed to very cold or hostile environmental conditions. 
         [0010]    One embodiment of the system of the present invention comprises an electrically powered fan having an inlet and an outlet, an electrically powered pump having a suction, discharge and a pumping chamber therebetween, one or more batteries to provide electrical current to operate the fan and the pump, a fuel storage container containing a volume of pressurized fuel, a fuel feed valve with an actuator to operate the valve and to control the rate at which a stream of fuel is released, an oxygen storage container containing a volume of pressurized oxygen, an oxygen feed valve with an actuator to operate the valve and to control the rate at which a stream of oxygen is released, a heat exchanger having an interior chamber to receive the stream of fuel and the stream of oxygen, a catalytic member received within the interior chamber of the heat exchanger to promote reaction of the fuel and the oxygen to produce heat and combustion by-products, a warming conduit having an inlet coupled to receive a stream of liquid from the pump discharge, an outlet and a warming portion therebetween disposed in thermal communication with the heat exchanger, at least one combustion by-product storage member disposed to receive a discharge stream of combustion by-products from the interior chamber of the heat exchanger, a cooling conduit disposed outside the chamber and including an inlet, and outlet and a cooling portion therebetween coupled to at least one planar fabric member that is adapted for being secured to a human, a liquid feed conduit coupled at a first end to the outlet of the warming conduit and at a second end to the inlet of the cooling conduit, a liquid return conduit coupled at a first end to the outlet of the cooling conduit and at a second end to the pump suction, and a volume of liquid disposed within a closed loop including the warming conduit, the cooling conduit, the liquid feed conduit, the liquid return conduit, the pump inlet, a pumping chamber intermediate the pump inlet and the pump outlet and within a housing of the pump, and the pump outlet, wherein the pump operates to move liquid through the closed loop, wherein the liquid moving through the warming conduit is warmed by the heat produced in the interior chamber, wherein the liquid moving through the cooling conduit is cooled by the human to whom the planar fabric member is secured, and wherein the combustion by-products are moved by the fan into the combustion by-product storage member where the combustion by-products are absorbed. 
         [0011]    In one embodiment of the present invention, the fuel is one of a hydrocarbon and an alcohol. For example, but not by way of limitation, the fuel may be one of methane, ethane, propane, butane, methanol or ethanol. In one embodiment of the present invention, the liquid used in the closed loop is stable and has a low viscosity for low flow resistance. For example, but not by way of limitation, the liquid is one of water, oil, a fluorocarbon and a derivative of a fluorocarbon. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         [0012]      FIG. 1  is an exploded view of an embodiment of a combustion assembly of the apparatus and system of the present invention. 
           [0013]      FIG. 2  is the assembled combustion assembly of  FIG. 1 . 
           [0014]      FIG. 3  is a perspective view of an embodiment of a heat exchanger assembly wearable by a user and compatible with the combustion assembly of  FIGS. 1 and 2 . 
           [0015]      FIG. 4  is a perspective view of an embodiment of a heat exchanger assembly wearable by a user and compatible with the combustion assembly of  FIGS. 1 and 2 . 
           [0016]      FIG. 5  is an illustration of the components of an embodiment of the present invention that make up a closed liquid loop of the apparatus and system of the present invention. 
           [0017]      FIG. 6  is an illustration of the components of an embodiment of the present invention that together store the reactants and the combustion by-products, and that generate heat. 
       
    
    
     DETAILED DESCRIPTION 
       [0018]      FIG. 1  is an exploded view of an embodiment of a combustion assembly  10  of the apparatus and system of the present invention. The combustion assembly  10  illustrated in  FIG. 1  comprises an elongate housing  29  having a proximal end  31 , a distal end  32  and an interior space  30  therebetween to receive a plurality of components to be discussed below. The combustible assembly  10  further includes a proximal cap  11  to sealably engage the proximal end  31  of the housing  29  and a distal cap  12  to sealably engage the distal end  32  of the housing  29 . At least one of: the housing  29 , the proximal cap  11  and the distal cap  12 ; include one or more sealed conduit ports through which conduits penetrate to supply warmed liquid from within the interior space  30  of the housing  29  to a heat exchanger assembly  50  (see  FIG. 3 ) external to the housing  29  (not shown in  FIG. 1 —see  FIG. 3 ), and to return cooled liquid from the heat exchanger assembly  50  to within the housing  29 . In embodiments such as the one illustrated in  FIGS. 1 and 2 , additional sealed conduit ports are required for the conduits that deliver fuel and oxygen form the fuel storage container  27  and the oxygen storage container  26 . 
         [0019]    The combustion assembly  10  of  FIG. 1  further comprises a desiccant containing carbon dioxide scrubber  13  having a proximal end  15 , a distal end  16  and an interior chamber  14 . The desiccant containing carbon dioxide scrubber  13  in  FIG. 1  has a cylindrical shape that generally conforms to the interior space  30  of the housing  29 . The desiccant pellets  28  are illustrated as being dispersed and suspended within the carbon dioxide scrubber  13 . The combustion assembly  10  further comprises a heat exchanger  17  having a proximal end  36 , a distal end  37 , an interior catalyst chamber  45  (not shown in  FIG. 1 ), and a coiled conduit  38  having an inlet  18  and an outlet  19 . The coiled conduit  38  wraps around the heat exchanger  17  between the inlet  18  and the outlet  19  a plurality of times to dispose a substantial length of the coiled conduit  38  in thermally conductive engagement with the heat exchanger  17 . The combustion assembly  10  further comprises a catalytic member  20  shaped so to be receivable within the interior catalyst chamber  45  of the heat exchanger  17 . The catalytic member  20  provides a large surface area on which a catalyst is disposed for promoting the reaction of the fuel from the fuel storage container  27  with the oxygen from the oxygen storage container  26 , as will be described in detail below. 
         [0020]    The combustion assembly  10  of  FIG. 1  further includes a fuel/air manifold  21 , a pump  22 , a fan  23 , a controller  24 , one or more batteries  25 , a fuel storage container  27  and an oxygen storage container  26 . It will be noted that the fuel storage container  27  is proximal to the proximal end  31  of the housing  29  and the catalytic member  20  is disposed within the catalyst chamber  45  of the heat exchanger  17 , which is proximal to the distal end  32  of the housing  29  to prevent unwanted heating of the fuel storage container  27  by the combustion within the catalyst chamber  45 . 
         [0021]      FIG. 2  is the assembled combustion assembly  10  of  FIG. 1  illustrating how many of the water-sensitive components shown in the exploded view of  FIG. 1  can be arranged within the interior space  30  of the housing  29 . The assembled combustion assembly  10  of  FIG. 2  includes the oxygen storage container  26  and the fuel storage container  27 , both of which are illustrated as being external to the housing  29 , the heat exchanger  17  with the coiled conduit  38  thereon, the desiccant containing carbon dioxide scrubber  13 , the fuel/air manifold  21 , the fan  23  and the pump  22 . It will be understood that the oxygen storage container  26  and the fuel storage container  27  can be included among the components disposed within the interior space  30  of a larger housing  29  or within the same housing if other components are made smaller. 
         [0022]      FIG. 3  is a perspective view of an embodiment of a heat exchanger assembly  50  wearable by a user  59  and compatible for use by the user  59  along with the combustion assembly  10  illustrated in  FIGS. 1 and 2 . The heat exchanger assembly  50  includes a garment  60 , which in  FIG. 3  is a vest, to which a cooling conduit  66  is secured in a serpentine or “switchbacked” pattern to provide for a greater length over which heat transfer to the user  59  can occur. The cooling conduit  66  includes a warmed liquid feed conduit  61  and a cooled liquid return conduit  65 . 
         [0023]      FIG. 4  is a perspective view of another embodiment of a heat exchanger assembly  50  wearable by a user  59  and compatible for use by the user  59  along with the combustion assembly  10  illustrated in  FIGS. 1 and 2 . The heat exchanger assembly  50  includes a garment  60 , which in  FIG. 4  is a pair of trousers or shorts, to which a cooling conduit  66  is secured in a serpentine or “switchbacked” pattern similar to that illustrated in  FIG. 3  to provide for a greater length over which heat transfer to the user  59  can occur. The cooling conduit  66  includes a warmed liquid feed conduit  61  and a cooled liquid return conduit  65 . It will be understood that the garment  60  of  FIG. 4  is an example only and, in other embodiments, the garment  60  may include extended leg portions with extended conduits  66  to carry warmed coolant to the user&#39;s lower legs.  FIG. 4  also illustrates how a plurality of cooling conduits  66  can be fluidically coupled in parallel and/or in series to distribute warmed coolant to separated body parts. 
         [0024]      FIG. 5  is an illustration of the components of an embodiment of the present invention that make up a closed fluid loop of the apparatus and system of the present invention. The closed fluid loop includes the coiled conduit  38  that is wrapped around the heat exchanger  17  between the proximal end  36  and the distal end  37  of the heat exchanger  17 . The coiled conduit  38  includes an inlet  18  to receive cooled liquid from the discharge outlet  88  of the pump  22  and an outlet  19  from which warmed liquid flows into the warmed liquid feed conduit  61  to the cooling conduit  66  that is secured to the garment  60  worn by the user  59 . The cooling conduit  66  within the fabric of the warming garment  60  terminates at the cooled liquid return conduit  65  through which liquid cooled in the garment  60  flows to the suction inlet  89  of the pump  22 . The pump  22  is a motorized pump that includes an electric motor that is powered by battery  25  through conductive conduits (wires)  81  and  82 . It will be understood that the closed liquid loop of  FIGS. 4 and 5  may, in some embodiments, include insulation to reduce heat loss in the warmed liquid feed conduit  61  or the cooled liquid return conduit  65 , in addition to check valves to manage fluid flow and bleed valves for use in removing unwanted air bubbles from the closed loop. 
         [0025]      FIG. 6  is an illustration of the components of an embodiment of the present invention that together store the reactants and the combustion by-products, and that generate heat.  FIG. 6  illustrates the use of the battery  25  to provide current flow through conductive conduits (wires)  92  and  93  to a motorized fan  23  that receives a stream of fuel released from fuel storage container  27  and a stream of oxygen released from oxygen storage container  26 . The fan  23  serves to mix the streams of fuel and oxygen into a combustible mixture, and to pressurize the combustible mixture for feeding the combustible mixture through the fuel/air manifold  21  into a proximal end  15  of an interior chamber  14  of the carbon dioxide scrubber  13  where the combustive mixture reacts in the presence of the catalytic member  20  (not shown in  FIG. 6 —see  FIG. 1 ) to produce heat and combustion by-products. At least some of the heat generated by the exothermic reaction of the fuel/air mixture transfers through the heat exchanger  17  (not shown—see  FIG. 1 ) to the coiled conduit  38  (not shown—see  FIG. 5 ). The combustion by-products, mainly carbon dioxide and water vapor, emerge from the distal end  16  of the carbon dioxide scrubber  13  and are forced by the presence of the distal cap  12  (not shown—see  FIG. 1 ) adjacent to the distal end  16  of the carbon dioxide scrubber  13  and by the pressure of the fan  23  to enter the distal end  16  of the desiccant containing carbon dioxide scrubber  13  as indicated by arrows  91 . 
         [0026]    It will be understood that, in the embodiment of the apparatus and system in  FIGS. 1-6 , that the distal end  16  of the cylindrically-shaped and desiccant containing carbon dioxide scrubber  13  is circular in shape and has a hole in the center at the interior chamber  14 . The carbon dioxide in the combustion by-product stream is absorbed by the material of the carbon dioxide scrubber  13  and the water vapor in the combustion by-product stream is absorbed by desiccant pellets dispersed in and supported within the carbon dioxide scrubber  13 . Any remaining, unabsorbed combustion by-product  91  exiting the distal end  16  of the desiccant containing carbon dioxide scrubber  13  will be absorbed by the distal face  92  of the desiccant containing carbon dioxide scrubber  13 . It will be understood that any remaining, unabsorbed combustion by-product  91  that is not absorbed by the distal face  92  will be diverted by the distal cap  12  of the housing  29  (see  FIG. 1 ) to the annular space intermediate the exterior  93  of the carbon dioxide scrubber  13  for further absorption into the desiccant containing carbon dioxide scrubber  13 . 
         [0027]    The desiccant containing carbon dioxide scrubber  13  and the desiccant pellets therein, if any, have a limited capacity to absorb carbon dioxide, and that the fuel storage container  27  and the oxygen storage container  26  each have a limited capacity to store fuel and oxygen, respectively. It will be understood that the volume of carbon dioxide produced can be correlated to the amount of fuel required to produce that volume of carbon dioxide, and that the amount of oxygen to combust the amount of fuel can also be determined. The anticipated duration of the dive and the anticipated temperature of the water are critical to determining how much fuel will be required to provide heat to the user  59  for that duration. Even the service time for the battery to power the pump  22  and fan  23  can be determined in advance of use of the apparatus and system of the present invention. 
         [0028]    It will be understood that the desiccant pellets may be separated from the carbon dioxide scrubber  13  in some embodiments of the apparatus of the present invention, and that the disclosure of a carbon dioxide scrubber  13  having a plurality of desiccant pellets distributed within and supported by the carbon dioxide scrubber  13  is a matter of convenience and practicality because the combustion by-products include a mixture of carbon dioxide and water vapor. The desiccant pellets of the carbon dioxide scrubber  13  of embodiments of the present invention may comprise one or more of silica, activated charcoal, calcium sulfate, calcium chloride and molecular sieves. 
         [0029]    Preferably, in one or more alternate embodiments, the apparatus and system of the present invention includes one or more of a hydrocarbon sensor, an oxygen sensor, a humidity sensor, a temperature sensor and a pressure sensor. These sensors may be used in conjunction with a controller to monitor and control the combustion process. 
         [0030]    For example, but not by way of limitation, a hydrocarbon sensor may be disposed upstream of the carbon dioxide scrubber to sense the concentration of unburned hydrocarbon gas, if any, entering the carbon dioxide scrubber. Unburned hydrocarbon gas would indicate that the combustible mixture of oxygen and fuel is too “rich,” meaning too much fuel for the rate at which oxygen is introduced into the combustion process. 
         [0031]    As another example, an oxygen sensor might be deployed to sense the amount of oxygen entering the carbon dioxide scrubber. An excessive amount of oxygen entering the carbon dioxide scrubber would indicate that the combustible mixture may be running too “lean,” meaning an insufficient rate of fuel for the rate at which oxygen is introduced into the combustion process. 
         [0032]    As another example, a humidity sensor might be deployed to sense the humidity in the combustion by-product stream entering the carbon dioxide scrubber. The humidity sensor will detect dramatic increases in the humidity level within the housing that contains the components of the device. An increasing humidity level will indicate either saturation of desiccant pellets or failure of the water absorption system. 
         [0033]    A temperature sensor may be deployed to sense the temperature of the fluid being discharged from the combustion assembly to the external heat exchanger assembly secured to the diver. An excessive temperature of the fluid would indicate that fuel and oxygen are being unnecessarily wasted and that the heat exchanger assembly secured to the diver is being maintained at an excessive temperature for the conditions. An insufficient temperature of the fluid would indicate that the rate of fuel and/or oxygen entering the combustion process is insufficient for the conditions. In one embodiment of the apparatus and system of the present invention, an additional temperature sensor is provided to monitor the temperature within the catalyst chamber. For example, a low catalyst chamber temperature, near ambient, would serve as an indicator that the apparatus and system are inactive and in a condition suitable for start-up. As another example, a high catalyst chamber temperature would serve as an indicator that there is a restriction in the closed fluid loop that prevents the heat exchanger from being continuously cooled. In one embodiment of the apparatus and system of the present invention, the temperature sensor may be a 10 k NTC thermistors to sense (measure) fluid temperature. NTC thermistors are available from AVX, EPCOS, GE, Honeywell, Murata, Vishay and other sources. 
         [0034]    A pressure sensor may be deployed to sense the pressure of the fluid stream being delivered from the combustion assembly to the external heat exchanger that is secured to the diver. An excessive pressure would indicate either that the pump is being operated at an excessive speed or that there is a restriction in the heat exchanger conduit in the heat exchanger assembly secured to the diver. An insufficient pressure would indicate that the pump is being operated at an insufficient speed or that there is a leak in the closed loop. Additional pressure sensors may be used to monitor the pressure within the fuel storage container and the pressure within the oxygen storage container. Another pressure sensor may be used to monitor the catalyst chamber to provide an alert or to close one or both of the fuel valve and the oxygen valve in the event of an overpressurization event. 
         [0035]    A battery sensor may be deployed to monitor the power level of the battery and to alert the user in the event that the battery power level falls below a predetermined alert level. It will be understood that a loss in battery power would render the fuel valve actuator and the oxygen valve actuator, in addition to the pump and the fan, inoperable. 
         [0036]    In one embodiment of the apparatus and system of the present invention, the carbon dioxide scrubber comprises Sodasorb® carbon dioxide absorbent or some other absorbent that selectively absorbs gaseous carbon dioxide from the stream of combustion by-products emerging from the catalyst housing. The carbon dioxide scrubber may contain a chemical that changes color when depleted or nearly depleted to provide a visual alert or a visual confirmation of the dwindling capacity of the carbon dioxide scrubber. In another embodiment of the apparatus and system of the present invention, the carbon dioxide scrubber comprises a Sofnolime® product such as, for example, Sofnolime® 797 or Sofnolime® CD. Sofnolime® is a product available from Molecular Products, Inc. of Boulder, Colo., USA. Embodiments of the carbon dioxide scrubber may further comprise desiccator pellets mixed into the carbon dioxide absorbent or confined to a separate compartment in the carbon dioxide scrubber from the carbon dioxide absorbent. The desiccator pellets will absorb the moisture component of the combustion by-products. 
         [0037]    The fan is needed to provide a positive head to move the reactants (fuel and oxygen) into the catalyst compartment of the heat exchanger and to move the combustion by-products from the catalyst chamber into the carbon dioxide scrubber, which includes the desiccant pellets. The fan is electrically powered using the one or more batteries. It will be understood that the fan capacity should be selected to minimize power consumption and to provide sufficient head to move the anticipated rate of combustion by-products through the carbon dioxide scrubber. 
         [0038]    In one embodiment of the apparatus and system of the present invention, the discharge outlet from the oxygen valve and/or the discharge outlet from the fuel valve are positioned immediately upstream of the fan to promote mixing of the fuel and the oxygen before the combustible stream enters the catalyst chamber. 
         [0039]    In one embodiment of the apparatus and system of the present invention, the housing is sealed to prevent water intrusion into the housing  29 . It will be understood that water, were it to contact the carbon dioxide scrubber  13 , the desiccant pellets therein, the catalyst member  20  or the controller and the various sensors, would cause failure or diminished performance of these components. The use of a proximal cap  11  and distal cap  12  enables the sealing of the proximal end  31  and the distal end  32  of the housing  29  to prevent water intrusion. The sealed housing  29  gives rise to the potential for over-pressurization of the housing  29 . In one embodiment of the apparatus and system of the present invention, a passive pressure relief device such as, for example, a spring-biased safety relief valve and/or a rupture disc, may be included within the housing  29 , the proximal cap  11  or the distal cap  12  to protect against housing rupture due to internal over-pressurization. 
         [0040]    It will be understood that, in some embodiments, the rate at which fuel is released from the fuel storage container  27  can be controlled by a fuel valve and the fuel valve actuator. Similarly, the rate at which oxygen is released from the oxygen storage container  26  can be controlled by the oxygen valve and the oxygen valve actuator. In addition, a manual shut-off valve on the fuel storage container  27  and a manual shut-off valve on the oxygen storage container  26  will facilitate safer assembly and operation of embodiments of the apparatus and system of the present invention. 
         [0041]    The shape and weight distribution of the combustion assembly of the apparatus and system of the present invention may be adapted for conveniently being secured to a user  59 . For example, but not by way of limitation, a vertical “stack” arrangement enables the combustion assembly to be secured to the back of a user with the proximal end  31  disposed upwardly, or proximal to the user&#39;s  59  head, and the distal end  32  to be disposed downwardly, or proximal to the user&#39;s  59  lower abdomen. This arrangement is frequently used by SCUBA divers for a breathing tank or by personnel entering a hostile environment for a respirator, air supply or air filtration unit. 
         [0042]    In one embodiment of the apparatus and system of the present invention, a purge valve penetrating a wall of the housing  29  is provided to enable the housing  29  to be purged using, for example, an inert gas, to remove any free hydrocarbons from the housing  29  prior to start-up and use. 
         [0043]    It will be understood that the various signals generated by one or more hydrocarbon sensors, oxygen sensors, humidity sensors, pressure sensors and/or temperature sensors will be routed to a controller, and that the controller would be programmed to generate output signals to the pump  22  to control the pump  22  speed, the fan  23  to control the fan  23  speed, the fuel valve actuator to control the rate at which fuel is released into the combustion process, and the oxygen valve actuator to control the rate at which oxygen is released into the combustion process. A microprocessor unit (MPU) having sufficient ports for sensor signal inputs and control signal outputs will perform this function. A model no. 8051f330 chip from Silicon Labs, Inc. or from other sources would be useful for many applications. 
         [0044]    The foregoing embodiments that include a microprocessor for control of valves, fan speed, pump speed or other components may include computer readable program code for implementing or initiating any one or more aspects of the methods described herein. Accordingly, a separate description of the methods will not be duplicated in the context of a computer program product. 
         [0045]    As will be appreciated by one skilled in the art, aspects of the present invention that include an MPU may be controlled or monitored using one or more computer program product codes. Accordingly, some automated or highly-controlled aspects of the present invention may take the form of an entirely hardware embodiment or an embodiment combining software and hardware aspects. 
         [0046]    The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, components and/or groups, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. The terms “preferably,” “preferred,” “prefer,” “optionally,” “may,” and similar terms are used to indicate that an item, condition or step being referred to is an optional (not required) feature of the invention. 
         [0047]    The corresponding structures, materials, acts, and equivalents of all means or steps plus function elements in the claims below are intended to include any structure, material, or act for performing the function in combination with other claimed elements as specifically claimed. The description of the present invention has been presented for purposes of illustration and description, but it is not intended to be exhaustive or limited to the invention in the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the invention. The embodiment was chosen and described in order to best explain the principles of the invention and the practical application, and to enable others of ordinary skill in the art to understand the invention for various embodiments with various modifications as are suited to the particular use contemplated.