Patent Publication Number: US-11661262-B2

Title: Thermal-insulation container

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This patent application claims priority to German utility patent application number 20 2019 105 348 filed Sep. 26, 2019 and titled “Thermal-Insulation Container”. The subject matter of patent application number 20 2019 105 348 is hereby incorporated by reference in its entirety. 
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not Applicable. 
     INCORPORATION BY REFERENCE OF MATERIAL SUBMITTED ON A COMPACT DISC 
     Not Applicable. 
     BACKGROUND 
     Thermal-insulation containers are receptacles for accommodating temperature-sensitive goods with an interior space which is separated from an exterior space in a thermally insulated fashion by means of thermally insulating walls. 
     Thermal-insulation containers of this generic type often exhibit the shape of a transport box in order to transport temperature-sensitive transport goods, such as foodstuffs or medication, at a controlled temperature. 
     Thermal-insulation containers are known, which are formed from a molded foam part, for example. In this case, the molded foam part is formed into a desired shape by foaming a foam material in a molding tool. For this purpose, the foaming material features thermal insulation properties. Thermal-insulation containers are known in the prior art from WO 2014/118 821 A1 and KR 10 2009 0 078 268 A. 
     Such thermal-insulation containers have the drawback that all walls have the same or a similarly high heat transfer coefficient. Hence, these thermal-insulation containers do not offer optimum thermal insulation properties, especially in those cases where the heat flux density of the external space acts anisotropically on the thermal-insulation container. In many applications, the heat flux density is particularly high in the region of the lid and the bottom. In regions of the thermally insulating walls of the thermal-insulation container where an increased heat flux density acts, the heat input into the thermal-insulation container is particularly high. Known thermal-insulation containers do not solve the problem of protecting specifically these regions of the thermal-insulation container from increased heat input. 
     SUMMARY 
     The present invention relates to a thermal-insulation container according to the independent claim. 
     It is the object of the invention to provide a thermal-insulation container which overcomes the drawbacks of prior art, whereby in particular a thermal-insulation container with optimized heat transfer coefficients of the respective thermally insulating walls is provided. 
     The object is achieved by the thermal-insulation container according to the independent claim. Advantageous embodiments constitute the subject-matter of the respective sub-claims. 
     The invention encompasses a thermal-insulation container which comprises a bottom, at least one, preferably four side walls each arranged on the bottom and a lid or a cover part arranged on the side walls. The bottom, the four side walls and the lid thereby completely enclose an interior space. In this regard, the lid has a heat transfer coefficient k D , the bottom has a heat transfer coefficient k B  and each of the side walls has one of the heat transfer coefficients k S1 , k S2 , k S3  or k S4 . Furthermore, k D &lt;minimum [k S1 , k S2 , k S3 , k S4 , k B ]. The particularly low heat transfer coefficient k D  of the lid is chosen in such a way to protect against a particularly high heat flux density, which for example is caused by solar radiation acting on the lid. For example, surfaces with lower emission coefficients, thicker design or lower thermal conductivity can be used. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    shows a schematic sectional view of a first thermal-insulation container; and 
         FIG.  2    shows a schematic sectional view of a second thermal-insulation container. 
     
    
    
     DETAILED DESCRIPTION 
     It is advantageous if k D &lt;k B &lt;minimum [k S1 , k S2 , k S3 , k S4 ]. The low heat transfer coefficient k B  of the bottom is chosen in such a way to protect against increased heat flux density caused, for example, by contact of the bottom with the ground on which the thermal-insulation container is placed. 
     A thermal-insulation container, where k D &lt;0.8 in particular 0.6*minimum [k S1 , k S2 , k S3 , k S4 , k B ], is particularly advantageous. 
     According to another advantageous aspect, the bottom, the four side walls and the lid each include at least one vacuum insulation panel. A vacuum insulation panel thereby has a thermal conductivity of less than 9 mW/mK, in particular less than 5 mW/mK, especially preferably less than 3.5 mW/mK. 
     It is preferred if the lid comprises at least two vacuum insulation panels, whereby the vacuum insulation panels are arranged stacked on top of each other. In this way, a lower heat transfer coefficient k D  of the lid can be easily realized. 
     A thermal-insulation container, wherein the bottom, the four side walls and the lid are made of the same material, is also preferred. In this context, the lid is designed thicker than the bottom and each of the four side walls. As a result, a lower heat transfer coefficient k D  of the lid can be realized in another simple way. 
     A thermal-insulation container comprising at least one pedestal, which is placed on the bottom, is especially preferred. The at least one pedestal is designed and arranged on the bottom in such a way that the bottom of the thermal-insulation container does not come into direct contact with the ground when the thermal-insulation container is placed on a ground. This reduces the heat flux over the bottom. 
     In the following, the invention will be explained in more detail using the examples shown in the attached drawings. Identical reference signs concern the same features in all figures. 
       FIG.  1    and  FIG.  2    show a thermal-insulation container  1 , which comprises a bottom  26 , four side walls  21 ,  23  [ 22 ,  24 ; the front and rear walls are not shown in this illustration] and a lid  25  arranged on the side walls. The bottom  26 , the four side walls  21 ,  23  and the lid  25  thereby completely enclose an interior space  3 . 
     In this context, the lid  25  has a heat transfer coefficient k D =0.083 W/(m 2 *K), the bottom  26  has a heat transfer coefficient k B =0.143 W/(m 2 *K), and each of the side walls  21 ,  23  has one of the heat transfer coefficients k S1 =k S2 =k S3 =k S4 =0.166 W/(m 2 *K). 
     Therefore, k D &lt;k B &lt;minimum [k S1 , k S2 , k S3 , k S4 ] applies. The particularly low heat transfer coefficient k D  of the lid  25  is chosen in such a way to protect against a particularly high heat flux density, which for example is caused by solar radiation acting on the top surface  251  of the lid  25 . The low heat transfer coefficient k B  of the bottom  26  is chosen in such a way to protect against an increased heat flux density which for example is caused by contact of the bottom  26  with the ground on which the thermal insulation container  1  is placed. 
     The shown thermal-insulation containers  1  comprise two pedestals  5 , which are arranged at the bottom  26 . The pedestals  5  reduce the heat flux over the bottom  26  when the thermal-insulation container  1  is placed on a ground, because the bottom  26  does not come into direct contact with the ground. 
     According to another advantageous aspect, the bottom  26 , the four side walls  21 ,  23  and the lid  25  each comprise at least one vacuum insulation panel  4 . While in  FIG.  1    the lid  25  comprises two vacuum insulation panels  4  arranged stacked on top of each other, in  FIG.  2    the lid  25  comprises a vacuum insulation panel  4   a  which is designed thicker than the vacuum insulation panels  4  of the bottom  26  and each of the four side walls  21 ,  23 . In both inventive embodiments, an optimized heat transfer coefficient k D  of the lid  25  can be easily realized in this way. Each of the vacuum insulation panels  4  shown thereby has a thermal conductivity of less than 9 mW/mK, in particular less than 5 mW/mK, especially preferably less than 3.5 mW/mK.