Patent Publication Number: US-2009235680-A1

Title: Cooling system by contact

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is the U.S. national phase of PCT/EP2007/054466, filed May 9, 2007. PCT/EP2007/054466 claims benefit under the Paris Convention to ES P-200601192, filed May 10, 2006. The disclosures of both of ES P-200601192 and PCT/EP2007/054466 are hereby incorporated herein by reference. 
    
    
     SUMMARY OF THE INVENTION 
     The present invention refers to a cooling system by contact. 
     BACKGROUND OF THE INVENTION 
     There are known different cooling systems by contact of a body or object, as will be described hereinafter. 
     U.S. Pat. No. 5,438,707 and U.S. Pat. No. 4,738,119 disclose, respectively, cooling devices of a body comprising a garment which houses a tubing network provided with little openings or micropores through which pressurized gas flows, such as air or carbon dioxide. Said pressurized gas, once injected, expands quickly through said openings or micropores cooling itself and absorbing a great quantity of heat, producing a cooling effect to the wearer of the garment. 
     Said devices present the drawback that they include at said garment a very extended and complex tubing circuit through which the cooling substance flows, resulting in a not very flexible garment. Furthermore, the tubes cool the garment only when the pressurized gas flows through them, but they cannot store frigories (negative calories) during a long time. In the other hand, any torn of said garment can affect the circuit, making the cooling device useless, and it can also promote a leak of said coolant which, depending on the kind of substance used, can involve a serious danger for the user of the device. 
     Furthermore, another drawback is that said devices cannot be used with refrigerants at a very low temperature, because in these devices the coolant contacts directly the wearer of the garment. 
     U.S. Pat. No. 5,787,505 discloses a device for cooling or heating a body comprising a garment with one or several pockets provided to insert a cooling or heating package. The cooling package comprises tight compartments containing water or other material which changes its state when absorbs heat, to cool therefore the wearer of said garment. 
     U.S. Pat. No. 5,038,779 discloses a therapeutic garment for back pains comprising at least one pocket at the lumbar area provided to house a cooling package. The pocket is made in one piece of a material folded on the garment. 
     Both devices discloses in this two documents have the drawback that they are not suitable to provide cooling at a very low temperature, because the cooling packages are in direct contact with the wearer of the garment. 
     The application of the international patent WO 2005112675, of the same applicant than the present invention, discloses a device for cooling a body comprising a garment in contact with said body, liquid nitrogen as coolant to cool said garment and storing means of said coolant. The garment comprises a layer of conducting fabric with a thermal conductivity suitable to transmit by contact the heat to said coolant. 
     This device has the drawback that the wearer of the garment must wear one or more deposits of liquid nitrogen, which the involved risk if there is a leak at each of said deposits. On the other hand, the use of cryogenic deposits makes the device expensive. 
     DESCRIPTION OF THE INVENTION 
     The objective of the cooling system by contact of the present invention is to solve the drawbacks known in the art, providing a number of advantages which will be described hereinafter. 
     The cooling system by contact of the present invention comprises a cooling fluid to cool a body or object, and at least a cold transmission surface in direct or indirect contact with said body or object, and it is characterized in that it comprises at least a device for collecting and storing frigories that can receive a preset quantity of cooling fluid from an external charging device, store said frigories and transmit them at a preset velocity and temperature to said cold transmission surface. 
     The present invention is directed to a cooling system by contact for engaging in a garment, comprising a cryogenic cooling fluid to cool a body or object, and at least a device for absorbing heat coming from said body or object through a cold transmission surface in direct or indirect contact with said body or object. It is characterized in that said device comprises a thermally isolated container, with the exception of a cold transmission surface in direct or indirect contact with the body or object to be cooled, said container comprising a radiator that can receive a preset quantity of said cryogenic cooling fluid from an external charging device, and in that said container also comprises a material around the radiator, filling the volume of the container not occupied by the radiator, said material having a thermal conductivity suitable for storing the negative calories (frigories) transferred by contact from said radiator, and for transmitting said negative calories (frigories) at a preset velocity and preset temperature to said cold transmission surface. 
     Therefore, the use of a cryogenic deposit forming part of the cooling system by contact is not necessary, as at the state of the art, and the security is enhanced because there is no risk of leaks and/or explosion when the pressure is increased, and the cost is considerably reduced. 
     Furthermore, the system provides a great autonomy because it can store a great quantity of frigories, about 20 to 40 Kilofrigories. 
     As stated above, in the system of the present invention, the cooling fluid is charged by an external charging device offering a pressure enough to inject said cooling fluid to the system. 
     When it is necessary to charge cooling fluid, the system of the invention is connected at that moment to the external charging device, transferring by injection the cooling fluid to the elements of the cooling system by contact, therefore transferring frigories thanks to the configuration of the elements of the system itself. 
     Preferably, said material is a viscous gel or a plastic filling the volume of the container not occupied by the radiator. 
     Advantageously, said container comprises at least a duct to exit the gas inside the radiator coming from the cryogenic fluid. 
     Advantageously, said at least one device for collecting and storing frigories comprises at least a thermal transmission element. 
     Preferably, each transmission element presents a thermal conductivity suitable to obtain a final preset temperature during an also preset time. 
     According to a first embodiment of the invention, the system is engaged on a garment. Advantageously, said at least one device for collecting and storing frigories comprises a thermally isolated container, with the exception of a cold transmission surface in direct or indirect contact with the body or object to be cooled. 
     Preferably, the container comprises a radiator provided with internal channels and external wings. 
     Advantageously, the container also comprises a viscous gel around the radiator, filling the volume of the container not occupied by the radiator. 
     According to a second embodiment of the invention, the system is engaged inside a protection helmet between an external layer and a cold transmission surface in contact with the head of the user. 
     Advantageously, said at least one device for collecting and storing frigories comprises a tube for conducting and distributing cooling fluid, preferably in spiral shape, occupying the whole extension of the helmet. 
     Preferably, the tube for conducting and distributing cooling fluid is placed inside a security padded layer. 
     Advantageously, said at least one device for collecting and storing frigories also comprises a layer of viscous gel placed between the tube for conducting and distributing cooling fluid and the cold transmission surface. 
     According to a third embodiment of the invention, the system is engaged to a fridge or cold recipient. 
     Advantageously, said at least one device for collecting and storing frigories comprises a container thermally isolated by an external isolating layer, with the exception of a cold transmission surface in direct or indirect contact with the internal part of the fridge. 
     Preferably, the container comprises a viscous gel. 
     Advantageously, the cooling fluid is a cryogenic fluid. Preferably, said cryogenic fluid is liquid nitrogen. 
     In anyone of the previous embodiments, the system comprises means for conducting and distributing said cooling fluid to said at least one device for collecting and storing frigories or, in other words, absorbing heat. 
     Advantageously, said means for conducting and distributing the cooling fluid include an intake duct provided at an end with an intake nozzle provided with a valve to be connected intermittently to the external charging device. 
     Preferably, said intake duct is joined at its other end to a distribution element distributing the cooling fluid to each device for collecting and storing frigories through secondary ducts. 
     Preferably, the attachment between the intake nozzle and the external charging device is of bayonet kind. 
     Advantageously, the system comprises control means for the temperature transfer. 
     Preferably, said control means for the temperature transfer comprises adjusting means of the distance between the body or object to be cooled and the cold transmission surface. 
     Advantageously, the system comprises means for storing the water generated by the condensation process, using it to increase the existing frigories. 
     Preferably, said means for storing condensation water comprises an absorbent fabric. 
     Alternatively, the system comprises waterproofing means preventing the condensation water to contact the body or object to be cooled, and means for collecting and evacuating said condensation water. 
     Optionally, the system is housed inside a thermally sealed garment to prevent condensation inside it. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       To make the description of that disclosed previously easier some drawings are attached in which, diagrammatically and only as a non-limitative example, some practical cases of embodiments of the cooling system by contact are shown, in which: 
         FIG. 1  is a frontal perspective view of a garment provided with the cooling system by contact, according to a first embodiment of the invention; 
         FIG. 2  is a rear perspective view of the garment of  FIG. 1 ; 
         FIG. 3  is a perspective view of the radiator; 
         FIG. 4  is a perspective view of the radiator placed inside the container without a lid; 
         FIG. 5  is a lateral section view of a helmet including the cooling system by contact, according to a second embodiment of the invention; 
         FIG. 6  is a plan view of the helmet of  FIG. 5 , showing the internal elements; 
         FIG. 7  is a perspective view of a fridge including the cooling system by contact, according to a third embodiment of the invention; 
         FIG. 8  is a plan view of the fridge of  FIG. 7 ; and 
         FIG. 9  is a transversal cross-section of a wall of the fridge of  FIGS. 7 and 8 . 
     
    
    
     DESCRIPTION OF PREFERRED EMBODIMENTS 
     Hereinafter three preferred embodiments of the cooling system by contact are described. 
     A first embodiment is shown if  FIGS. 1 to 4 , where it can be seen that the cooling system  1  by contact is applied to a garment  2 , such as a vest. 
     In this case, the cooling system  1  by contact comprises three devices  3  for collecting and storing frigories arranged on the vest  2 , and that can receive a preset quantity of cooling fluid, specifically liquid nitrogen, from an external charging device (not shown). 
     To do this, the system  1  comprises means to conduct and distribute the liquid nitrogen comprising an intake duct  4  provided at an end with an intake nozzle  5  provided with a valve to be connected intermittently to the external charging device. Said intake duct  4  is connected by its other end to a distributing element  6  which distributes the liquid nitrogen to each device  3  for collecting and storing frigories through secondary ducts  7 . 
     The attachment between the intake nozzle  5  and the external charging device can be a system of bayonet kind, because it is an efficient and comfortable attachment. Therefore, it is assured that there are no disconnection problems from the contractions produced when the liquid nitrogen flows. The nozzle  5  can be housed inside the vest  2 , and it can be uncovered by a zip, and when the charge is finished, it can be hidden inside the garment  2 . 
     The design of the ducts  4  and  7  is ergonomic, so that they can remain disguised and they do not disturb the wearer. 
     The material suitable for the conduction and distribution means  4  to  7  of the liquid nitrogen is a non-metallic material such as Teflon, Pyrex, Armaflex, among others, the metallic material being not suitable because it can crack. 
     Another option consists in not using conducting and distributing means of the liquid nitrogen, so that each collecting and storing device  3  of frigories is fed directly from the external charging device. Therefore, the ergonomics of the garment  2  is enhanced. 
     With reference to  FIGS. 3 and 4 , each collecting and storing device  3  of frigories comprises a container  8  thermally isolated, except a wall  9  with a minimum width, which will contact the garment  2 , acting as a cold transmission surface, as will be explained hereinafter. 
     The container  8  can be made from a plastic material, such as polyurethane; and the cold transmission surface  9  can be made from plastic or metallic material, taking into account that the metal will provide to the garment  2  a temperature lower than about −30° C., compared with the plastic material, which will provide about −15° C. 
     The container  8  comprises a body with a lid which houses inside it a radiator  10  provided with internal channels (not shown) and external wings  11 . The material suitable for the radiator  10  is a metal, such as aluminum, copper, and steel, among others. 
     The charge of liquid nitrogen is injected inside  30  the radiator  10  through an intake duct  12 , and flows through internal channels, so that said radiator  10  can collect frigories from the nitrogen when it pass through the channels, and it can increase the temperature from −198° C. (temperature of the liquid nitrogen) to about −160° C. (temperature at which the nitrogen changes its state from liquid to gas). The gas inside the radiator  10  exits outside the container  8  through exit ducts  13 , providing the last frigories to the system  1 . 
     On the other hand, the container  8  comprises a viscous gel (not shown) surrounding the metallic radiator  10  and filling the volume of the container  8  not filled by the radiator  10 . The design of the radiator  10  is optimized thanks to the external wings  11  to provide a maximum 10 contact area with the gel. 
     Said gel has a thermal conductivity suitable for storing transferred from the metallic radiator  10  by contact, passing from about −160° C. to about −40° C. 
     It must be pointed out that the gel permits to transmit cold slowly during a preset time to the cold transmission surface  9  of the container  8 , which receives a temperature of about −15° C. This temperature is suitable to be supported by the human body during about two hours when it is under conditions of environmental heat of more than 100° C., as is the case of firemen. The system can provide between 20 and 40 Kilofrigories, providing a great autonomy. 
     The used gel can be any known gel, whose thermal properties permit to reach a suitable final temperature and to transmit cold during a preset time. Even though gel is the more suitable material because of its easy placement and adaptation to the external surface of the metallic radiator  10 , it must be pointed out that it could be used a plastic material in the place of gel, such as polypropylene, polyethylene, among others. 
     The container  8  makes, therefore, the functions of containing the radiator  10  and the gel, and also of permitting the transfer of temperature through the surface  9  presenting a thickness of 0.2 mm. 
     Therefore, in this first embodiment there are three layers transmitting frigories between the liquid nitrogen and the garment  2 , which are: the metallic radiator  10 , the gel, and the surface  9  which transmits  5  cold of the container. 
     The system  1 , once assembled, can be autoportable, i.e. it can comprise a fixation between the different components by elastic harnesses and straps. 
     A second embodiment is shown is  FIGS. 5 and 6 , where it can be seen that the cooling system  1   a  by contact is applied to a helmet  20 , such as a motorist helmet. The system  1   a  is placed between an external layer  21  of the helmet and a surface  22  in contact with the head of the user, which will have the function of cold transmission surface, as it will be described hereinafter. 
     In this case, the cooling system  1   a  by contact comprises a single device  3   a  for collecting and storing frigories suitable to receive a preset quantity of cooling fluid, specifically liquid nitrogen, from an external charging device (not shown). 
     To do this, the system  1   a  comprises a tube  23  to conduct and distribute the liquid nitrogen, in the shape of a spiral, placed inside a security padded layer  24 , to cover efficiently the whole surface of the helmet  20 . Said tube  23  comprises an intake nozzle  25  provided with a valve to be connected intermittently to the external charging device. The material suitable for said conduction and distribution tube  23  of the liquid nitrogen is Teflon, and metal cannot be used for security reasons. Therefore, the tube  23  of Teflon can collect quickly a great quantity of frigories, and it can increase the temperature from −198° C. of the liquid nitrogen to about −160° C. 
     Adjacent to said padding layer  24  there is a layer  26  of gel (not shown) with a thermal conductivity suitable to collect frigories transmitted by the tube  23  of Teflon through the padding layer  24 , and storing them during a preset time, passing from about −160° C. to about −40° C. 
     It must be pointed out that gel permits to transmit slowly the cold during a preset time to the cold transmitting surface  22 , which receives a temperature of about −15° C., being this temperature suitable to be supported by the human body during about two hours when it is under environmental heat conditions of more than 40° C., such as Formula One drivers. 
     Therefore, in this second embodiment there are two cold transmission layers between the liquid nitrogen and the layer  22  of material of the helmet in contact with the head of the user, which are the tube  23  of Teflon and the gel. 
     A third embodiment is shown in  FIGS. 7 to 9 , where it can be seen that the cooling system  1   b  by contact is applied to a fridge or cold recipient  30 , that can be placed in a double bottom. 
     In this case, the cooling system  1   b  by contact comprises four devices  3   b  to collect and store frigories placed each one in a wall of the fridge  30 , that can received a preset quantity of cooling fluid, specifically liquid nitrogen, from an external charging device. 
     To do this, the system  1   b  comprises conduction and distribution means of the liquid nitrogen comprising a main duct  31  provided at an end with an intake nozzle  32  provided with a valve to be connected intermittently to the external charging device. The liquid nitrogen is distributed to each collecting and storing device  3   b  of frigories through secondary ducts  33 . The suitable material for the conducting and distribution means of the liquid nitrogen is a non-metallic material, such as Teflon, Pyrex, Armaflex, among others, the metal being not suitable because it can crack. 
     Each collecting and storing device  3   b  of frigories comprises a container  34  thermally isolated by an isolating external layer  35 , except a wall  36  which will be in contact with the internal part of the fridge  30 , acting as a cold transmission surface, such as will be described hereinafter. 
     Each container  34  houses inside it gel (not shown) with a thermal conductivity suitable to collect frigories from the liquid nitrogen and store them during a preset time, passing from about −198° C. to about −40° C. 
     It must be pointed out that gel permits to transmit slowly the cold during a preset time to the cold transmission surface  36  in contact with the internal part of the fridge  30 . 
     Therefore, in this third embodiment there is one frigories transmission layer between the liquid nitrogen and the cold transmission surface  36  in contact with the internal part of the fridge  30 , which is the gel. 
     The system  1   b  can also be used in vehicles of transportation of perishable products to maintain the legal established temperature to preserve the food in harmless conditions and suitable to be consumed. 
     In anyone of the described embodiments control means of the transfer of temperature can be used, consisting in adjusting the distance between the contact surface with the user or object to be cooled and the cold transfer surface to modify the interchange of frigories. E.g. in the case of the garment or helmet, said control means can consist in an air chamber provided between the cold transmission surface and the human body, and said air chamber can be inflated when the final temperature is too low; or, in the case of the fridge, it can consist in other kind of means separating two metallic surfaces, one of them being the cold transmission surface. 
     It must be pointed out that in some environments, the container can present a water condensation greater than that expected. When the user pretends to use the own condensation, the system can include means to store the water generated by the condensation process, using it afterwards to increase the existing frigories. To do this, said means for storing the condensing water can comprise an absorbent fabric. 
     When it is not wished to use the condensation water, the system can comprise waterproofing means preventing the condensation water to contact the body or object to be cooled, and means to collect and evacuate said condensation water. E.g. in the case of a garment or helmet, it can include a tube at its lower part to evacuate the water. In the case of a fridge, it can include known systems to prevent the condensation. 
     Furthermore, the system of the invention can be housed inside a thermally sealed garment to prevent condensation inside it.