The subject matter disclosed herein relates to climate controlled cargo containers. More specifically, the subject matter disclosed herein relates to a wall panel(s) used in a climate controlled cargo container.
A typical climate controlled cargo container, such as those utilized to transport cargo via sea, rail or road, is a container modified to include a refrigeration unit. The refrigeration unit includes a compressor, condenser, expansion valve and evaporator coil, located at an end of the container. A volume of refrigerant circulates throughout the refrigeration unit, and one or more evaporator fans of the refrigeration unit blows a flow of air across the evaporator coil cooling the air and forcing it into the container.
As the cargo container is climate controlled, it is desirable to provide the cargo container with insulated walls, ceiling and/or floor to retain thermal energy in the container. Improvements in insulated wall panels for cargo containers would be well received in the art.
In one embodiment a climate controlled cargo container includes at least one panel including: an outer layer; an inner layer; a foam positioned in between the inner layer and the outer layer; and a plurality of fiber tubes embedded within the foam.
In another embodiment, a climate controlled cargo container includes at least one panel including: an outer layer; an inner layer; a foam positioned in between the inner layer and the outer layer; and a phase change material positioned between the inner layer and the outer layer.
These and other advantages and features will become more apparent from the following description taken in conjunction with the drawings.
The subject matter, which is regarded as the invention, is particularly pointed out and distinctly claimed in the claims at the conclusion of the specification. The foregoing and other features, and advantages of the invention are apparent from the following detailed description taken in conjunction with the accompanying drawings in which:
Shown in
Positioned interior to the first foam 56 is a second foam 58. Second foam 58 is an open cell foam, and may be polyurethane, or another type of open cell foam. Embedded within the second foam 58 are fiber tubes 60. Fiber tubes 60 may have a variety dimensions. Fiber tubes 60 have porous walls and gas flows freely through the pores on the membrane walls. This allows a fast evacuation of the gases trapped in the cells of foam 58 adjacent to the fiber tube outer walls. The porous wall of the fiber tubes 60 make fluid connections to the cells of foam. The open cells of foam 58 and tubes 60 form channels that have much higher resistance to heat flow.
In an exemplary embodiment, the fiber tubes 60 may be carbon fiber tubes. The tube walls may have a porosity of about 30% to about 80%. The tube walls may have a pore size of about 0.01 microns to about 0.4 microns. The tube wall thickness may be from about 5 microns to about 150 microns. The tube inner diameter may be from about 5 microns to about 100 microns.
The fiber tubes 60 provide evacuation channels within the second foam 58 by interconnecting open cells within the second foam 58. The channels in second foam 58 improve the evacuation of the blowing agent for the second foam 58 under vacuum to improve R value.
Insulated panel 50 may be manufactured by forming and curing sections of first foam 56 and then assembling the first foam sections between the outer layer 52 and inner layer 54. First foam 56 may be encased in an air-tight barrier (e.g., plastic film) to preserve a vacuum in the panel. The second foam 58 is then blown into the cavity interior the first foam 56 sections through one or more ports 62. Fiber tubes 60 may be positioned in the cavity prior to blowing the second foam 58 or the fiber tubes 60 may be intermixed with the second foam 58 during the blowing procedure. Several areas of second foam 58 may be blown at the same time through a plurality of ports 62 coupled to a header.
Once the second foam 58 has cured, a vacuum is applied to the second foam 58 to evacuate the blowing agent and form a vacuum in the open cells of second foam 58 and in the channels formed by fiber tubes 60. The vacuum may be applied to the port 62 used to blow in second foam 58. The port(s) 62 may be sealed to preserve the vacuum in second foam 58. Alternatively, a low-cost vacuum system may continuously evacuate second foam 58 through ports 62. The vacuum may also be conditioned to run only at certain times (e.g., only when the compressor is running).
Panel 66 is formed in a manner similar to panel 50. Outer layer 52 and inner layer 54 are joined by structural members 64 at one or more locations and the second foam 58 is blown into the cavity between outer layer 52 and inner layer 54. The cavity may be lined with an air-tight barrier (e.g., plastic film) to preserve a vacuum in the panel. Fiber tubes 60 may be positioned in the cavity prior to blowing the second foam 58 or the fiber tubes may be intermixed with the second foam 58 during the blowing procedure. Several areas of second foam 58 may be blown at the same time through a plurality of ports 62 coupled to a manifold, described with reference to
Panels 50 and 66 provide an improved R-value while still providing structure for container 10. Either of panels 50 and 66 may be used for walls, ceiling, floor, first end or second end of container 10. At second end 24, either of panels 50 and 66 would be incorporated into doors providing access to the interior of container 10.
Positioned interior to the first foam 72 is second foam 74. Second foam 74 is an open cell foam, and may be polyurethane, or other type of open cell foam. Embedded within the second foam 74 and/or first foam 72 are fiber tubes 60. Fiber tubes 60 may have a variety dimensions. In an exemplary embodiment, the fiber tubes 60 may be carbon fiber tubes, having an inner diameter of 60 microns and an outer diameter of 100 microns, and varying lengths. The fiber tubes 60 provide evacuation channels within the second foam 74 by interconnecting open cells within the second foam 58. The channels in second foam 74 improve the evacuation of the blowing agent for the second foam 74. Foam 74 may also include high R-value aerogels incorporated during the two part mixing of foam 74 or pre-formulated into one of the two reactant parts of foam 74. Aerogels in foam 74 may be silica, carbon, alumina, or other known aerogels.
Insulated panel 70 may be manufactured by forming and curing the first foam 72 sections (with or without aerogels) and then assembling the first foam sections 72 between the outer layer 52 and inner layer 54. First foam 72 may be encased in an air-tight barrier (e.g., plastic film) to preserve a vacuum in the panel. The second foam 74 (with or without aerogels) is then blown into the cavity interior the first foam 72 sections through one or more ports 62. Fiber tubes 60 may be positioned in the cavity prior to blowing the second foam 74 or the fiber tubes may be intermixed with the second foam 74 during the blowing procedure. Several areas of second foam 74 may be blown at the same time through a plurality of ports 62 coupled to a header.
Once the second foam 74 has cured, a vacuum is applied to the second foam 74 to evacuate the blowing agent and form a vacuum in the open cells of second foam 74 and in the channels formed by fiber tubes 60. The vacuum may be applied to the ports 62 used to blow in second foam 74. Aerogels in second foam 74 help to define additional channels due to the open cell nature of aerogels. The panel 70 may be sealed to preserve the vacuum in second foam 74 by sealing ports 62. Alternatively, a low-cost vacuum system may continuously evacuate second foam 74 through the ports 62. The vacuum may also be conditioned to run only at certain times, (e.g., only when the compressor is running).
Outer layer 52 and inner layer 54 are joined by structural members 64 at one more locations and the second foam 82 (with aerogels) is blown into the cavity between outer layer 52 and inner layer 54. The cavity may be lined with an air-tight barrier (e.g., plastic film) to preserve a vacuum in the panel. Fiber tubes 60 may be positioned in the cavity prior to blowing the second foam 82 or the fiber tubes may be intermixed with the second foam 82 during the blowing procedure. Several areas of second foam 82 may be blown at the same time through a plurality of ports 62 coupled to a manifold, described with reference to
Panels 70 and 80 provide an improved R-value while still providing structure for container 10. Panels 70 and 80 may be used for walls, ceiling, floor, first end or second end of container 10. At second end 24, panels 70 and 80 would be incorporated into doors providing access to the interior of container 10.
Positioned interior to sections of the first foam 56 is a phase change material panel 92. Phase change material panel 92 stores thermal energy to aid in maintaining cargo 12 at a desired temperature. Phase change material panel 92 may be made from a material having a melting point defined relative to (e.g., approximately equal to or above) the desired shipping temperature of cargo 12. As the temperature within container 10 increases, the phase change material 92 will reach its melting point, and absorb heat in transitioning from a solid state to a liquid state. Panels 90 may be pre-cooled to place phase change material panel 92 in a solid state prior to shipping container 10. This reduces the load on the compressor of refrigeration unit 14 and provides an ability to absorb heat.
Insulated panel 90 may be manufactured by forming and curing the first foam 56 sections, placing encapsulated phase change material panel 92 in between the first foam 56 sections and then mounting the outer layer 52 and inner layer 54 to the first foam 56. Alternatively, insulated panel 90 may be manufactured by forming and curing the first foam 56 sections and then assembling the first foam sections 56 between the outer layer 52 and inner layer 54. The phase change material 92 is then pumped into the cavity interior the first foam 56 sections through one or more ports 62. Ports 62 may then be sealed to hold the phase change material panel 92 within panel 90.
Phase change material particles 104 store thermal energy to aid in maintaining cargo 12 at a desired temperature. Phase change material particles 104 may be made from a material having a melting point defined relative to (e.g., approximately equal to or above) the desired shipping temperature of cargo 12. As the temperature within container 10 increases, the phase change material particles 104 will reach a melting point, and absorb heat in transitioning from a solid state to a liquid state. Panels 100 may be pre-cooled to place phase change material particles 104 in a solid state prior to shipping container 10. This reduces the load on the compressor of refrigeration unit 14.
Outer layer 52 and inner layer 54 are joined by structural members 64 at one more locations and the second foam 102 is blown into the cavity between outer layer 52 and inner layer 54. Several areas of second foam 102 may be blown at the same time through a plurality of ports 62 coupled to a header.
Panels 90 and 100 provide an improved R-value while still providing structure for container 10. Increased overall insulation performance (higher effective R value) is due to the combined effect of the capacity of thermal energy storage provided by the phase change materials and a pre-defined phase change temperature. Further, peak heat flux of panels 90 and 100 is reduced due to the energy storage of the phase change material. Panels 90 and 100 may be used for walls, ceiling, floor, first end or second end of container 10. At second end 24, panels 90 and 100 would be incorporated into doors providing access to the interior of container 10.
While the invention has been described in detail in connection with only a limited number of embodiments, it should be readily understood that the invention is not limited to such disclosed embodiments. Rather, the invention can be modified to incorporate any number of variations, alterations, substitutions or equivalent arrangements not heretofore described, but which are commensurate with the spirit and scope of the invention. Additionally, while various embodiments of the invention have been described, it is to be understood that aspects of the invention may include only some of the described embodiments. Accordingly, the invention is not to be seen as limited by the foregoing description, but is only limited by the scope of the appended claims.
Filing Document | Filing Date | Country | Kind |
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PCT/US13/32931 | 3/19/2013 | WO | 00 |
Number | Date | Country | |
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61650592 | May 2012 | US |