Abstract:
An apparatus for selectively heating and cooling a body via a garment and attached heat transfer tubing. Operation of the garment is unaffected by external loads applied to the garment, such as backpack straps or harnesses. The garment includes restriction-resistant heat transfer tubing. The tubing is made of flexible, resilient material and has a lumen through which temperature-controlled fluid flows. In one embodiment, the lumen includes three internal protrusions or ribs extending radially from the inner wall and rounded at the tip. When an external load is applied to the tubing the internal ribs prevent complete closure of the lumen because the ribs provide support that separates the opposite sides of the tubing. The ribs, therefore, resist restriction of the flow of the heat transfer fluid. In various embodiments, the tubing and ribs take on different shapes while maintaining an open lumen through which temperature-controlled fluid may flow.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   Not Applicable 
   STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
   Not Applicable 
   BACKGROUND OF THE INVENTION 
   1. Field of Invention 
   This invention pertains to an apparatus for selectively heating and cooling a body. More particularly, this invention pertains to the tubing that carries a temperature-controlled fluid over the surface of a garment worn on the body of a person and the tubing has an internal construction configured to resist restriction of the fluid flow when an external load, or force, is applied to the tubing. 
   2. Description of the Related Art 
   Oftentimes, individuals must perform tasks in extreme temperature environments. 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. When the ambient temperature is very hot, the individual can remove only so much clothing in order to obtain relief. In order to perform tasks in these extreme temperature environments, the individual can wear a garment that includes a heat transfer mechanism to allow the individual to endure the extreme temperature environment. These garments typically have tubing routed over the surface of the garment, and the tubing carries a temperature-controlled fluid. 
   One such garment is disclosed in U.S. Pat. No. 4,024,730, titled “Integrated cooling and breathing system,” issued to Bell, et al., on May 24, 1977. The &#39;730 patent discloses an integrated cooling and breathing system for crewmembers aboard an aircraft. The &#39;730 patent further discloses a crewmember 39 wearing a liquid-loop cooling garment 55 that includes “a capillary-like system of flexible tubing 53 integral with a nylon fabric underwear-like suite.” 
   U.S. Pat. No. 6,109,338, titled “Article comprising a garment or other textile structure for use in controlling body temperature,” issued to Butzer on Aug. 29, 2000, discloses a garment with pockets and tube casings for use in cooling body temperature. The &#39;388 patent discloses a system of heat transfer patches within the garment which are fluidly connected by tubing routed through tube casings. 
   U.S. Pat. No. 6,565,699, titled “Method and apparatus for making body heating and cooling garments,” issued to Szczesuil, et al., on May 20, 2003, discloses a method of fabricating garments with fluid carrying tubing. The &#39;699 patent discloses a garment that includes heating or cooling tubing dispersed throughout the garment. The tubing of the &#39;699 patent is supplied with heating or cooling fluids via an umbilical connection line which is connected to a heating/cooling unit. 
   Oftentimes, when an individual is performing a task in an extreme temperature environment, the individual must also wear other equipment, such as an air-supply pack or a backpack, or the individual must be strapped into a seat with a harness. Such equipment and/or harness is often secured tightly to the individual with straps. These straps press against the heat transfer tubing, causing the tubing to collapse and thereby restricting flow of the temperature-controlled fluid and limiting the temperature control available to the user. Accordingly, there is a need to have a garment that remains functional when an individual is performing tasks requiring a piece of equipment and/or a harness that is supported by the body of the person. 
   One approach to resolve this restriction of flow is disclosed in U.S. patent application Ser. No. 11/562,788, titled “Upper Body Heating an Cooling Apparatus and Method of Making Same,” filed Nov. 22, 2006, incorporated by reference, which discloses a garment with a load bearing area and a heat transfer area. The load bearing area is identified at the shoulders of the upper body. The heat transfer tubing is located away from the load bearing area to avoid a fluid flow restriction in that area. 
   BRIEF SUMMARY OF THE INVENTION 
   According to one embodiment of the present invention, a garment with heat transfer tubing is provided. The garment has an outside surface. The heat transfer tubing is attached to the garment, in one embodiment, by sewing the tubing to the outside surface of the garment. The tubing defines a lumen that carries a temperature-controlled fluid that provides cooling or heating to the body. The tubing has internal features that keep the lumen open when pinched, or compressed, by an external load, such as the straps of a backpack or of a harness worn over the garment. 
   One embodiment of the tubing has three ribs that protrude into the lumen and run longitudinally along the length of the tubing. The ribs are dimensioned and configured such that the lumen is not closed when an outside force is applied to the tubing. When the tubing is deformed by the outside force such that a portion of the tubing wall is forced toward the opposite portion of the tubing wall, the tip of the ribs contact the opposite portion of the tubing wall, thereby preventing the tubing from collapsing and closing the lumen. The tubing has an inlet and an outlet. Temperature-controlled fluid flows into the inlet, runs through the tubing, and exits the outlet. When an external load is applied to the tubing, the internal ribs prevent the walls of the tube from being forced together, thus allowing the heat transfer fluid to circulate despite the external load. 

   
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
     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: 
       FIG. 1  is a front perspective view of one embodiment of a thermal garment with heat transfer tubing; 
       FIG. 2  is a perspective view of a short length of one embodiment of the heat transfer tubing; 
       FIG. 3  is a cross-sectional view of one embodiment of the heat transfer tubing; and 
       FIG. 4  is a cross-sectional view of one embodiment of the heat transfer tubing in a compressed state. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   An apparatus for thermal transfer that includes restriction-resistant heat transfer tubing is disclosed. The illustrated embodiment is a thermal garment  100  to be worn on the upper body of a human. In other embodiments, the thermal garment  100  is configured to be worn over various portions of the body. 
     FIG. 1  illustrates a perspective view of one embodiment of a thermal garment  100  with heat transfer tubing  104  attached. In the illustrated embodiment, the thermal garment  100  includes a shirt  102  with heat transfer tubing  104  attached to the outside of the shirt  102 . The tubing  104  is flexible, resilient, and does not appreciably stretch or compress. The tubing  104  is laid out in a serpentine manner over a heat transfer portion of the outside surface of the shirt  102  with an inlet  106  and an outlet  108  for the flow of a temperature-controlled fluid. The inlet  106  and outlet  108  of the tubing  104  are connected to connectors  118  that allow the tubing  104  to be in fluid communication with a thermal unit. The thermal unit forces a temperature-controlled fluid into the inlet  106 , through the tubing  104 , and out of the outlet  108 . The tubing  104  is sized to accommodate the flow of fluid from the thermal unit to meet the thermal needs of the wearer. 
   When the temperature-controlled fluid is cooler than the ambient temperature and the body temperature of the wearer, the thermal garment  100  transfers heat from the wearer of the shirt  102  to the fluid, thereby cooling the wearer. Multiple fluid circuits allow the cooling effects to be evenly spread across the heat transfer portion  110  of the shirt  102 . To maintain the comfort of the wearer, the flow of temperature-controlled fluid through the tubing  104  should not be stopped when an external load is applied to the shirt  102 , such as, for example, when the shirt  102  is worn by a race car driver and the seat belt presses against the tubing  104 . The external loads tend to adversely impact the heat transfer capability of the garment by causing pinching, crushing, compression, or otherwise restricting the flow of the fluid within the heat transfer tubing  104 . The restriction of flow also builds up backpressure in the system that can damage the pump and motor of the thermal unit. 
   In the illustrated embodiment, the tubing  104  is attached to the outside of the shirt  102 . In other embodiments, the tubing  104  is attached to the inside of the shirt  102 , between two or more layers of material forming the garment  100 , or within pockets in the garment  100 . 
   In the illustrated embodiment, the tubing  104  is positioned on both the front and rear sides of the shirt  102  and there are two circuits of tubing  104  on the front heat transfer portion  110  of the shirt  102 . In other embodiments, the tubing  104  is positioned along the sides of the upper body and/or along the arms of the shirt  102 . Although the illustrated embodiment is a shirt  102  covering the upper body portion of a person, in other embodiments the thermal garment  100  covers various portions of the body of the wearer and the tubing  104  is positioned on a heat transfer portion  110  adjacent the surface of the material forming the garment  100 . 
     FIG. 2  illustrates a perspective view of a short length of one embodiment of the heat transfer tubing  104 .  FIG. 3  illustrates a cross-sectional view of one embodiment of the heat transfer tubing  104 . In one embodiment, the tubing  104  is sewn to the fabric of the shirt  102  with thread  204  that alternates from side-to-side of the tubing  204 . The illustrated embodiment of the heat transfer tubing  104  has a substantially constant circular cross-section in its relaxed state. The heat transfer tubing  104  has an outside diameter  306 , a wall  302 , and three internal ribs  202 . The tubing wall  302  forms a lumen  304  through which the fluid flows. 
   The tubing wall  302  has a thickness. The type of material and thickness of the wall  302  creates an impermeable barrier to retain the fluid within the lumen  304 . There exists a minimum cross-sectional area of the lumen  304  for the thermal garment  100  to function properly. Extreme temperature differentials are uncomfortable to the wearer. A larger lumen  304  allows for the use of a fluid with a more moderate temperature to effectuate the same heat transfer as a tubing with a smaller lumen  304 . Assuming the wall thickness remains constant, a larger lumen  304  will require a larger outside diameter  306 . The cost of heat transfer tubing  104  increases as the outside diameter  306  increases. The heat transfer tubing  104  is being used in a garment  100  that will be worn on a body, so weight is also an issue. The weight of the heat transfer tubing  104  increases as the outside diameter  306  increases where the thickness of the wall  302  remains constant. In order to minimize both cost and weight of the heat transfer tubing  104 , the cross-sectional area of the lumen  304  must be minimized. The minimum cross-sectional area of the lumen  304  is dependent on the desired temperature differential between the temperature-controlled fluid and the body being treated. Another consideration for the size of the lumen  304  is the amount of pressure required to pump the fluid through the tubing  104 . A very small lumen  304  creates a high back pressure that must be overcome by the pump. The designer must balance the comfort of the user and the cross-sectional area of the lumen  304 , keeping in mind the cost of the pump required to circulate the fluid through the system. 
   In the illustrated embodiment, three internal ribs  202  extend from the wall  302  and are 120 degrees apart. In other embodiments, the number of ribs  202  varies. Each rib  202  is a longitudinal member having a width  312  and a height  308  when viewed in cross-section. In one embodiment, each rib  202  extends partially toward the center of the cylindrical-shaped tubing  104  when the tubing  104  is in its natural state as illustrated in  FIGS. 2 and 3 . In various embodiments, the width  312  and height  308  of the ribs  104  varies depending upon the resilience of the material of the tube  104 . 
   The cross-sectional area of the lumen  304  for a conduit with a simple circular inside diameter is decreased when the internal ribs  202  are added. To maintain the same cross-sectional area as a lumen  304  without protruding internal ribs  202 , the outside diameter  306  of the heat transfer tubing  104  is increased to compensate for the area of the protruding internal ribs  202 . The internal ribs  202  have a radial height  308  of sufficient size to maintain a minimum cross-sectional area of the lumen  304  when pinched with a full radius at the end, or tip,  310 . The width  312  of the internal ribs  202  is sufficient to resist bending, crushing, or otherwise deforming of the rib  202  under compression such that the minimum cross-sectional area is not compromised. In one embodiment, the internal ribs  202  extend longitudinally along the heat transfer tubing  104 . The internal ribs  202  are substantially continuous over the length of the heat transfer tubing  104 . In another embodiment, the thickness of the wall  302  may be reduced, but the wall  302  must be thick enough to provide an impermeable barrier for the fluid. 
   In the illustrated embodiment, the tubing  104  has three internal ribs  202  extending radially from the wall  302  with a full radius at the end  310 . In other embodiments, the tubing  104  may have one or more internal ribs  202  and the ribs  202  may take on a triangular, curved or other shape that performs the same function of keeping the lumen  304  from collapsing completely. In various embodiments, the tubing  104  is connected to various connectors  106 ,  108 ,  118  by a sealed interface between the connectors  106 ,  108 ,  118  and the outside surface of the tubing  104 . In one such embodiment, the tubing is connected to various connectors  106 ,  108 ,  118  by a compression connection with a sealed interface between the connectors  106 ,  108 ,  118  and both the inside and outside surfaces of the tubing  104 . In another embodiment, the tubing  104  has sufficient resiliency that a barbed section of a connector is inserted into an end of the tubing  104  to form a sealed connection to the tubing  104 . 
     FIG. 4  illustrates a cross-sectional view of one embodiment of the heat transfer tubing  104  in a compressed state  104 ′, as it may appear when a backpack strap or a harness in a race car seat applies an external load or force  402  on one side, or wall,  302 -A of the tubing that causes that portion of the wall  302 -A to be displaced toward the opposite wall  302 -B of the tubing  104  as the tubing  104  deforms. The heat transfer tubing  104 ′ is resilient and will return to its free state  104  when the compressing load or force  402  is removed. Those skilled in the art will recognize that the orientation of the ribs  202  will vary from that illustrated in  FIG. 4  depending upon the orientation of the tubing  104  when the force  402  is applied. 
   When an external load, or force,  402  is applied to the heat transfer tubing  104 , the tubing  104 ′ deforms with a portion of the tubing wall  302 -A moving toward the opposite wall portion  302 -B. One or more ribs  202  prevent the two wall portions  302 -A,  302 -B from contacting each other and closing the lumen  304 ′ and preventing the flow of fluid through the tubing  104 ′. As the two wall portions  302 -A,  302 -B move toward each other, at least one rib protruding from one wall portion  302 -B extends toward the opposite wall portion  302 -A. When the tip, or end,  310  of the rib  202  contacts the wall portion  302 -A, the wall portion  302 -A is stopped from contacting the opposite wall portion  302 -B. 
   The internal ribs  202  have a height  308  and width  312  that are dimensioned to prevent the walls  302 -A and  302 -B from touching each other, thus maintaining the minimum cross-sectional area of the lumen  304 ′ to minimize the impact on the heat transfer capability of the thermal garment  100 . The size (height  308  and width  312 ) of the internal ribs  202  determines the cross-sectional area of the lumen  304  when the tubing is in its compressed state  104 ′. 
   The thermal garment  100  includes the function of resisting restriction of fluid flow. This function is implemented, in one embodiment, by the internal ribs  202 . The thermal garment  100  includes heat transfer tubing  104  assembled adjacent to a material forming the garment  100  for the body or a part of the body. When an external load, or force,  402  is applied to the garment  100 , the walls  302 -A and  302 -B are prevented from touching and closing the lumen  304 ′ by the internal ribs  202 . In its compressed state  104 ′, the tubing maintains the lumen  304 ′ equal to or greater than its minimum cross-sectional area. 
   From the foregoing description, it will be recognized by those skilled in the art that a thermal garment  100  that operates under typical loads such as the straps of a backpack or of a harness assembly has been provided. The garment  100  includes a length of heat transfer tubing  104  which carries temperature-controlled fluid. The tubing  104  has internal features that prevent the walls  302  from closing when an external load, or force,  402  is applied to the tube  104 . 
   According to one embodiment of the present invention, a garment  100  with heat transfer tubing  104  is provided. The garment  100  has an outside surface. The heat transfer tubing  104  is attached to the garment  100 , in one embodiment, by sewing the tubing  104  to the outside surface of the garment  100 . The tubing  104  carries a temperature-controlled fluid that provides cooling or heating to the body. The tubing  104  has internal features that keep the lumen  304  open when pinched, or compressed, by an external force  402 , such as applied by the straps of a backpack or a harness. 
   One embodiment of the tubing  104  has three internal ribs  202  that protrude into the lumen  304  and run longitudinally along the length of the tubing  104 . The tubing  104  has an inlet  106  and an outlet  108 . Temperature-controlled fluid flows into the inlet  106 , runs through the tubing  104 , and exits the outlet  108 . When an external force  402  is applied to the tubing  104 , the internal ribs  202  prevent the walls  302 -A and  302 -B of the tubing  104  from begin force together, thus allowing the heat transfer fluid to circulate despite the external force  402 . 
   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.