Abstract:
Apparatus for cooling a person in extreme environments. The apparatus includes a garment having a vest with attached tubing. The vest includes an evaporative cooling device and the tubing is configured to circulate chilled water. The vest includes a material that is able to receive and absorb an amount of liquid water with a mass greater than the material. When liquid water is applied to the vest, the vest absorbs the water for later evaporation. The tubing enables the garment to have a lower differential temperature between the inside surface and the outside surface, thereby reducing the rate of evaporation, which enables the passive cooling to be operable for an extended period of time. When the heat load does not permit the differential temperature to be reduced, the tubing removes additional heat, thereby providing additional heat removing capacity beyond the passive cooling.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of U.S. Provisional Application No. 61/046,429, filed Apr. 20, 2008. 
     
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
       [0002]    Not Applicable 
       BACKGROUND OF THE INVENTION 
       [0003]    1. Field of Invention 
         [0004]    This invention pertains to a garment configured to be worn by a person or animal in a hot environment. More particularly, this invention pertains to a garment with multiple modes of cooling. 
         [0005]    2. Description of the Related Art 
         [0006]    Many occupations require exposure to severe environments, such as those with extreme temperatures. When the ambient temperature is very cold, an individual can wear insulative layers of clothing, although at the expense of mobility, flexibility, and overall size or bulk. When the ambient temperature is very hot, the individual can remove only so much clothing in order to obtain relief. Often, in such an environment, the individual must wear protective clothing and gear, which cannot be readily or completely removed. 
         [0007]    For example, firefighters enter burning buildings that frequently have exposed flames and are filled with smoke. In order to protect themselves, firefighters wear protective clothing, air packs, helmets with face shields, and other gear. Wearing the protective clothing in hot, fire filled buildings leads to heat exhaustion for firefighters and limits the time that the firefighter is available for combating the fire. Athletes also often face overheating conditions, for example, a football player practicing in the summer heat. 
         [0008]    It is not uncommon for such persons to combat heat exhaustion by dousing themselves with cool water to lower their body temperature. Water sprays or misting systems also provide a cooling effect through evaporative cooling. Severe cases of heat exhaustion and heatstroke are treated by immersion in a cool water bath or by the application of ice packs to the body. 
         [0009]    Another way to combat heat exhaustion is active cooling. For example, Published Patent Application Number 2007/0085340, titled “Upper Body Thermal Device with Quick-Disconnect Connectors,” discloses a garment with tubing attached to the outside of the fabric. The tubing carries conditioned fluid for cooling the body of a wearer. The thermal effect from such a garment is limited by the area covered by the tubing carrying the liquid and the temperature of the liquid. 
       BRIEF SUMMARY OF THE INVENTION 
       [0010]    According to one embodiment of the invention, a multi-mode cooling garment includes both active cooling and passive cooling features to achieve longer lasting and more rapid cooling of a person or animal than that available from only active cooling and passive cooling. A particular advantage of the garment is that cooling is available for an extended time. The garment includes a vest with tubing attached to the vest. The vest is an evaporative cooling device that receives liquid water and permits the water to evaporate over time. The tubing is part of an active cooling device that circulates conditioned fluid for heat transfer. 
         [0011]    In one embodiment, the vest has an inner layer that is water resistant, a middle layer that absorbs liquid water and releases water vapor, and an outer layer that passes water as a liquid and a vapor. The middle layer includes a polymer, such as a superabsorbent polymer or polyacrylamide. The polymer absorbs liquid water and releases it as the water evaporates. The evaporation cools the wearer of the vest. Attached to the vest is tubing that circulates cooled water. The circulating water removes heat from the vest and reduces the temperature differential between the inner and outer layers. 
         [0012]    For evaporative cooling, cooling lasts only as long as fluid remains for evaporation, and the amount of fluid is directly related to the size and weight of the evaporative cooling device. For active cooling, cooling lasts only as long as a source of cold producing material is available, and the quantity of cold producing material is directly related to the size and weight of the active cooling device. With both evaporative and active cooling, the garment has reduced bulk and weight compared to an equivalent garment with only evaporative or active cooling. Also, with both evaporative and active cooling, the garment has increased heat transfer capabilities compared to an equivalent garment with only evaporative or active cooling. 
         [0013]    The garment is part of a system that includes multiple garments that connect to a water supply. The water supply includes manifolds for connecting the multiple garments to a pump drawing chilled water from a reservoir. In one embodiment, the reservoir contains ice and water. The ice melts from the warm water returned from the tubes on the garment. The melting ice cools the water in the reservoir and the cooled water is circulated to the garment where the water absorbs heat. During the time the water is circulating, the garment is also undergoing evaporative cooling. Before use, the vest is soaked in water to allow the vest to absorb the liquid. In use, the water evaporates. Because the circulating water in the tubes is removing heat, the rate of evaporation is better matched to the heat load on the garment. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         [0014]    The above-mentioned features of the invention will become more clearly understood from the following detailed description of the invention read together with the drawings in which: 
           [0015]      FIG. 1  is a perspective view of one embodiment of a multi-mode cooling garment; 
           [0016]      FIG. 2  is a front view of the back of one embodiment of the inside of the cooling garment that is turned inside-out; 
           [0017]      FIG. 3  is an exploded diagram showing one embodiment of the layers of a garment; and 
           [0018]      FIG. 4  is a schematic diagram showing a one embodiment of multi-mode cooling system. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0019]    Apparatus for a multi-mode cooling system  400  with multiple cooling garments  100  is disclosed. The system  400  includes garments  100  with multi-mode cooling, that is, the garments  100  include both active cooling and passive cooling features, which results in a cooling system that lasts longer and cools more rapidly than a comparable garment with only active cooling or passive cooling. As used herein, a garment is a covering for a portion of the body, such as an article of clothing like a vest, shirt, or pants. 
         [0020]      FIG. 1  illustrates a perspective view of one embodiment of a multi-mode cooling garment  100 .  FIG. 2  illustrates a front view of the back  118  of one embodiment of the inside of the cooling garment  100  that is turned inside-out. The illustrated garment  100  includes a vest  102  and several sections of tubing, or fluid conduit,  114  attached to the vest  102  with thread  116 . The garment  100  is an article of clothing configured to fit around a portion of the body of the wearer. 
         [0021]    The vest  102  includes a front section  120  and a back section  118 . The front section  120  of the vest  102  is in two halves that are releasably connected with a zipper  108 . In other embodiments, the two halves of the front section  120  are releasably joined with another type of fastener, for example, a hook and loop fastening system or buttons or snaps. The two sections  118 ,  120  of the vest  102  are joined at each side with a gusset  122 . In one embodiment, the gusset  122  is an elastic material that allows the two sections  118 ,  120  to better conform to the shape of the wearer&#39;s torso. An elastic gusset  122  ensures that the inside of the garment  100  contacts as much of the wearer as possible and prevents the garment  100  from sagging or fitting loosely, which would decrease the cooling effect on the wearer. 
         [0022]    The vest  102  includes a material that absorbs liquid water quickly and subsequently allows the water to evaporate. The evaporation of the water transfers heat from the garment  100  and from the wearer. Evaporative cooling provides the passive cooling feature of the garment  100 . 
         [0023]    In  FIG. 2  the garment  100  is turned inside-out and the view illustrates the serpentine arrangement of the tubing  114  on the inside back surface  118  of the garment  100 . The material of the inside surface fabric is substantially water resistant such that the fluid retained by the garment  100  does not wick to or wet an object in contact with the inside surface  118 . For example, a person wearing a shirt under the garment  100  would feel cooler wearing the garment  100 , but the person&#39;s shirt would not be dampened or wetted by any fluid from garment  100 . 
         [0024]    In the illustrated embodiment, the tubing  114  is sewn to the inside surface of the vest  102  with a thread  116 . The tubing  114  is arranged in multiple loops with the ends terminated in a manifold  110  with a connector end  112 . Each of the manifolds  110  connect the connector end  112  to four ends of tubing  114 . The ends of the tubing  114  are illustrated protruding from the side of the vest  102  below a gusset  122 . In other embodiments the ends of the tubing  114  protrude for another part of the vest  102  so as to provide a convenient attachment to a source of cooling water. For example, the ends of the tubing  114  exit from the bottom of the back section  118 , which is convenient for allowing the connectors  112  to automatically disconnect when the wearer moves forward. 
         [0025]    Each loop or run of tubing  114  extends from one manifold  110  to the other manifold  110 . The tubing  114  follows a serpentine path on the surface of the vest  102  and the serpentine path is configured to evenly distribute the tubing  114  on the surface of the vest  102  to ensure even heat transfer between the tubing  114  and the wearer of the garment  100  and between the tubing  114  and the vest  102 . 
         [0026]    A heat transfer or heat exchange area is defined where the tubing, or fluid conduit,  114  is attached to the vest  102 . For example, in the illustrated embodiment, the tubing  114  is arranged in a serpentine pattern on the front section  120  and the back section  118  of the vest  102 , but not on the sides of the vest  102  where the gussets  122  are located. Such a configuration positions a heat transfer area adjacent the front of the wearer and a heat transfer area adjacent the wearer&#39;s back. The sides of the garment  100  do not have a heat transfer area and, subsequently, the sides are less bulky and allow the wearer freedom of movement of the arms. In another embodiment, the fluid conduit  114  is formed as a conduit or fluid pathway in or attached to the vest. For example, the fluid conduit  114  is formed by joining two layers together in all areas except where the fluid conduit  114  is located. 
         [0027]      FIG. 3  illustrates an exploded diagram showing one embodiment of the layers of the garment  100 . The vest  102  incorporates passive cooling. In the illustrated embodiment, the vest  102  has three layers: an inner layer  302 , an outer layer  306 , and a middle layer, or filler,  304 . The layers  302 ,  304 ,  306  form a sandwiched structure, or sheet, with the layers  302 ,  304 ,  306  adjacent to each other and contacting each other. In one such embodiment, the layers  302 ,  304 ,  306  are joined loosely, such as by quilting or stitching through the layers  302 ,  304 ,  306 .  FIG. 2  illustrates the quilt stitching  202  on the back section  118  of the vest  102 . The quilting stitching  202  allow the middle layer  304  to expand in thickness without being compressed between the inner and outer layers  302 ,  306 . The middle layer  304  expands in thickness when the middle layer  304  absorbs the liquid water as the vest  102  is charged with liquid water. 
         [0028]    In other embodiments, at least two of the layers  302 ,  304 ,  306  are bonded or integrally formed, for example, the inner layer  302  is a skin or treated surface of the middle layer  304 . In one such embodiment, the inner layer  302  is a surface on the middle layer  304  and the outer layer  306  is a surface on the middle layer  304 . For example, the middle layer  304  is a porous material and the inner layer  302  is a surface of the middle layer  304  that is impermeable or water resistant. 
         [0029]    In the illustrated embodiment, the tubing  114  is adjacent the inner layer  302 . In the illustrated embodiment, the tubing  114  is attached to the layers by sewing the tubing  104  to the vest  102  with thread  116 . In one such embodiment, a coating is applied to the inner layer  302  to seal the openings created by sewing the threads  116 , thereby preventing seepage or wicking of any fluid in the vest  102  to anything inside the vest  102 . In other embodiments, the tubing  114  is positioned between the layers  302 ,  304 ,  306  or adjacent the outside layer  302 . An advantage of positioning the tubing  114  adjacent the inner layer  302  is that the outer layer  306  has a surface area for evaporation that is maximized and not blocked by the tubing  114  on the outer surface. Such an advantage is also realized if the tubing  114  is positioned between the inner and outer layers  302 ,  306 , for example, in the middle layer  302  adjacent the inner layer  302 . 
         [0030]    The vest  102  is an evaporative cooling device. The inner layer  302  defines the interior of the garment  100  because it is adjacent the body of the wearer. The inner layer  302  and is a fabric, sheet, or film that prevents or inhibits fluid from the vest  102  passing or wicking to anything inside the vest  102 , such as a layer that is water repellent or water resistant. A water repellent layer is one that resists but is not impervious to water. A water resistant layer is one resisting, though not entirely preventing, the penetration or passage of water. In one embodiment, the inner layer  302  is impermeable or impervious to water and water vapor. 
         [0031]    The outer layer  306  is a porous material that freely passes water vapor during evaporation. The outer layer  306  also passes liquid water to charge the middle layer  304 . The outer layer  306  has a porous region through which the liquid water and water vapor passes. The middle layer  304  includes a material that absorbs liquid water and releases it as water vapor after a phase change. The outer layer  306  is impermeable or impervious to the water absorbing material in the middle layer  304 . 
         [0032]    In one embodiment, the middle layer  304  includes a polymer embedded fabric that contains highly absorbent crystals or superabsorbent polymers. Superabsorbent polymers (SAP) (also called slush powder) are polymers that can absorb and retain extremely large amounts of a liquid relative to its own mass. In another embodiment, the middle layer  304  includes embedded polyacrylamide crystals. Polyacrylamide crystals are capable of absorbing and retaining large quantities of water compared to the weight and volume of the polyacrylamide crystals. 
         [0033]    To charge the vest  102  for use, the garment  100  is immersed in liquid water for one or more minutes. The middle layer  304  quickly absorbs the liquid as the vest  102  charges. When the garment  100  is worn after being charged, the heat from the body wearing the garment  100  and the heat from outside sources, such as the sun, causes the middle layer  304  to release the water through evaporation. The water in the middle layer  304  evaporates using heat energy for the phase transition and thereby cooling the garment  100  and the wearer. 
         [0034]    The rate of evaporation is slower than the uptake of water by the middle layer  304 , thereby providing evaporative cooling for an extended period. The rate of evaporation determines the amount of heat removed by passive cooling and the time passive cooling is available. The rate of evaporation is determined by various factors, such as the relative humidity and the temperature differential between the inner and outer layers  302 ,  306 . The normal temperature differential during use of the garment  100  is that the inner layer  302  has a higher temperature than the outer layer  306 . The inner layer  302  is heated by the body wearing the garment  100 . The outer layer  306  is cooled by evaporative cooling of the middle layer  304 . 
         [0035]    The tubes  114 , with cool water flowing through them, provide active cooling for the garment  100 . The cool water flowing through the tubes  114  absorb a portion of the heat from the body wearing the garment  100 . The cool water flowing through the tubes  114  also lowers the temperature differential between the inner and outer layers  302 ,  306  by decreasing the temperature of the inner layer  302 , which is also being cooled by evaporation of the water in the middle layer  304 . The lower differential temperature reduces the rate of evaporation, thereby allowing the middle layer  304  to function as an evaporative cooler for a longer time. For the case where the heat load is such that the tubes  114  cannot reduce the temperature differential, the additional cooling from the tubes  114  aids in removing heat from the body wearing the garment  100  because the evaporative cooling can remove only a limited amount of heat for a specific differential temperature. 
         [0036]      FIG. 4  illustrates a schematic diagram showing a one embodiment of multi-mode cooling system  400 . The system  400  includes a multitude of garments  100 -A,  100 -B,  100 -C, and a cool water supply  402 .  FIG. 4  illustrates a simplified schematic of one embodiment of a cooling system  400 . The simplified schematic does not illustrate various connections, for example, isolation valves and tubing connectors between the various components; however, those skilled in the art will recognize the need for such components and understand how to construct such a system  400 . 
         [0037]    Each garment  100  includes an inlet connector  112 - i  and an outlet connector  112 - o . The inlet connectors  112 - i  are connected to conduit connected to an outlet manifold  404 - o  of the water supply  402  and the outlet connectors  112 - o  are connected to a conduit connected to an inlet manifold  404 - i  of the water supply  402 . Although only three garments  100 -A,  100 -B,  100 -C are illustrated, the system  400  is able to use various numbers of garments  100 . In one such embodiment, the manifolds  404  are appropriately sized to accommodate the number of garments  100  desired to be connected to the system  400 . 
         [0038]    The water supply  402  includes a pump  406  and a reservoir  408 . The pump  406  takes suction from the reservoir  408  and supplies pressurized water to the outlet manifold  402 - o . The pressurized water is then pushed through the conduits to the inlet connectors  112 - i  of the connected garments  100 . The pressurized water circulates through the tubing  114  and discharges through the outlet connectors  112 - o , where it enters the inlet manifold  404 - i . The inlet manifold  404 - i  collects the discharges from the connected garments  100  and directs the discharges to the reservoir  408 . The reservoir  408 , in one embodiment, is filled with water and ice to provide chilled water to the garments  100 . For example, block ice or loose ice is placed in the reservoir  408 , along with a little water. The reservoir  408  is insulated such that the water returned from the garments  100  is the primary heat source that causes the ice to melt, thereby cooling the water. In one such embodiment, the pump  406  is battery operated and the water supply  402  is portable. In another embodiment, the reservoir  408  is filled with water that is chilled by a chilling unit that maintains the water at a desired temperature. In yet another embodiment, the water supply  402  provides warmed or heated water to the garments  100 , which are suitable for use in a cold environment. 
         [0039]    The garment  100  and cooling system  400  include various functions. The function of cooling passively is implemented, in one embodiment, by the vest  102  having a material that is able to receive and absorb an amount of liquid water with a mass greater than the material receiving the water. In one such embodiment, the material is a polymer that is contained within the vest  102 , for example, by being embedded in a fabric or contained in a bag or pouch. 
         [0040]    The function of cooling actively is implemented, in one embodiment, by the tubing  114  attached to the vest  102 . In one such embodiment, the tubing  114  has a connector  112  attached at each end. The connectors  112  attach to a conduit that is in fluid communication with a water supply  402 . 
         [0041]    The function of supplying water to a garment  100  is implemented, in one embodiment, by a water supply  402  that contains a pump  406  and a reservoir  408 . The reservoir  408  is configured to hold a volume of water. 
         [0042]    From the foregoing description, it will be recognized by those skilled in the art that a garment  100  and cooling system  400  has been provided. It is advantageous to combine active cooling with evaporative cooling in a single, multi-mode cooling garment  100 . Doing so results in a less bulky, smaller sized, and lighter weight garment  100  than either an active cooling garment or an evaporative cooling garment. The garment  100  with passive cooling working in conjunction with active cooling results in a cooling device that cools faster and for a longer time than a device with only passive or active cooling. These advantages allow the multi-mode cooling garment  100  to be more comfortable when worn for extended periods. 
         [0043]    In one embodiment of the multi-mode cooling garment  100 , the garment  100  is an evaporative cooling garment with active cooling tubing arranged within defined areas of the garment  100 . The active cooling portion of the multi-mode cooling garment  100  allows the garment  100  to be less bulky and lighter in weight than an evaporative cooling garment, by itself, with the same temperature differential and duration of cooling. Likewise, the addition of evaporative cooling to an active cooling system allows the active cooling system to remain active for a longer duration and/or use less cold producing material, such as an ice block or crushed ice. Requiring less cold producing material allows the supporting equipment for the active cooling garment to be smaller in size and lighter in weight. 
         [0044]    While the present invention has been illustrated by description of several embodiments and while the illustrative embodiments have been described in considerable detail, it is not the intention of the applicant to restrict or in any way limit the scope of the appended claims to such detail. Additional advantages and modifications will readily appear to those skilled in the art. The invention in its broader aspects is therefore not limited to the specific details, representative apparatus and methods, and illustrative examples shown and described. Accordingly, departures may be made from such details without departing from the spirit or scope of applicant&#39;s general inventive concept.