US20050194381A1

US20050194381A1 - Insulated cargo containers

Info

Publication number: US20050194381A1
Application number: US11/072,293
Authority: US
Inventors: Ronald Zupancich; Joseph Seiter
Original assignee: Martin Marietta Materials Inc
Current assignee: Martin Marietta Materials Inc
Priority date: 2004-03-05
Filing date: 2005-03-07
Publication date: 2005-09-08

Abstract

The prevention discloses an insulated cargo container. In one implementation, the insulated cargo container includes at least one insulating panel applied on an exterior surface of the side walls, end walls, roof, or doors of the cargo container. In another implementation, the floor of the cargo container is also modified to improve the thermal efficiency of the cargo container.

Description

I. CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. Provisional Application No. 60/549,929, filed Mar. 5, 2004, by Ronald J. Zupancich and Joseph A. Seiter and titled Insulated Cargo Containers, the disclosure of which is expressly incorporated herein by reference.

II. BACKGROUND

A. Technical Field
The present invention relates to a method of insulating a cargo container and an insulated or refrigerated cargo container. In one embodiment, the cargo container is a railroad boxcar.
B. Related Art
Currently, many shippers utilize insulated or refrigerated large cargo containers (such as boxcars) to transport items that require the maintenance of specified temperatures during transit. Because these containers are required to maintain certain temperatures, the thermal efficiency of these containers is an important feature. Thermal efficiency is characterized by the thermal conductivity of a particular component or its inverse, its resistance to heat transfer commonly referred to as an R value.
In the past, large cargo containers were typically constructed of a combination of wood and metal members. Because members of this type typically possessed a low R-value, insulation, such as foam insulation, was often installed in these cargo containers to increase their thermal efficiency. Even with the use of insulation; however, the thermal efficiency of cargo containers of this type has not been as high as desired by users of these cargo containers. Therefore, there is a need for methods of constructing cargo containers with improved thermal efficiency.
One such existing method has involved placing additional insulating materials on the interior of the container. One drawback of this method is that placing additional insulating materials on the interior of the container reduces the interior dimensions of the cargo container. In turn, reducing the interior dimensions of the cargo container reduces the amount of space available for cargo. In addition, insulating materials located on the interior of a cargo container can also be subject to damage from the placement of cargo in the containers. This also reduces the thermal efficiency of the cargo container. Therefore, there is a need for methods of constructing cargo containers with improved thermal efficiency without substantially reducing the interior dimensions of the car and making the insulating panels less susceptible to loading damage.
The present invention provides a method of constructing cargo containers with improved thermal efficiency without reducing the interior dimensions of the car.

II. SUMMARY OF THE INVENTION

An apparatus consistent with the present invention provides a cargo container including an underframe having a top and bottom surface; a floor connected to the underframe; first and second side walls having exterior surfaces; first and second end walls having exterior surfaces, and a roof having an exterior surface. The underframe, floor, first and second side walls; first and second end walls, and roof form an enclosure. The cargo container also includes at least one insulating panel comprising an insulating layer and at least one outer skin located on at least one face of the insulating layer. The at least one insulated panel is located on the exterior surface of at least one of the first side wall, second side wall, first end wall, second end wall, or roof.
Another apparatus consistent with the present invention provides a cargo container including an underframe having a top and bottom surface; a liner having a top surface and located on the top surface of the underframe; and a floor located on the top surface of the liner. The cargo container also includes first and second side walls having exterior surfaces; first and second end walls having exterior surfaces, and a roof having an exterior surface. The underframe, floor, first and second side walls; first and second end walls, and roof form an enclosure. The cargo container also includes at least one insulating panel comprising an insulating layer and at least one outer skin located on at least one face of the insulating layer. The at least one insulated panel is located on the exterior surface of at least one of the first side wall, second side wall, first end wall, second end wall, or roof.
Another apparatus consistent with the present invention provides a cargo container including an underframe having a top and bottom surface; a liner having a top surface and located on the top surface of the underframe; at least one insulating member on the top surface of the liner; and a floor located on the at least one insulating member. The cargo container also includes first and second side walls having exterior surfaces; first and second end walls having exterior surfaces, and a roof having an exterior surface. The underframe, floor, first and second side walls; first and second end walls, and roof form an enclosure. The cargo container further includes at least two insulating panels comprising an insulating layer and at least one outer skin located on at least one face of the insulating layer. The at least two insulating panels are located on the exterior surface of at least one of the first side wall, second side wall, first end wall, second end wall, or roof. In addition, each insulating panel is connected to at least one other insulating panel located on the same exterior surface.
Additional objects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention will be realized and attained by means of the elements and combinations particularly pointed out in the appended claims.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed.
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate several embodiments of the invention and together with the description, serve to explain the principles of the invention.

III. BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a perspective view of a boxcar;
FIG. 1B is a side view of a boxcar;
FIG. 2 is a perspective view of an insulated panel consistent with one embodiment of the invention;
FIG. 3 is a perspective view of a boxcar with insulated panels installed consistent with one embodiment of the invention;
FIG. 4A illustrates two insulated panels with connectors consistent with one embodiment of the invention;
FIG. 4B is a cut-away illustration of a portion of two insulated panels with connectors consistent with one embodiment of the invention; and
FIG. 5 illustrates a modified floor consistent with one embodiment of the invention.

IV. DESCRIPTION OF THE EMBODIMENTS

A. Introduction
As described below, methods and apparatus consistent with the present invention will now be described with respect to the modification of one embodiment of an existing cargo container: a boxcar. The invention as claimed, however, is broader than boxcars and extends to the modification of other large insulated cargo containers, such as, shipping containers used on seagoing container vessels, truck trailers, straight trucks, refrigerated buildings, or the like.
B. Apparatus and Methods
FIGS. 1A-1B illustrate two views of a boxcar, one type of cargo container. A boxcar is an enclosed rail car used to transport freight. As shown in FIGS. 1A-1B, a boxcar 100 includes side walls 110, a roof 120, a floor 130, end walls 140, and a door opening 150. Wall panels 110, roof 120, floor 130, and end walls 140 combine to form an enclosure 160. Door opening 150 provides access to enclosure 160. Enclosure 160 can be used to store articles at specified temperatures. As shown in FIG. 1B, boxcar 100 may also include doors 170.
As described above, the thermal efficiency of boxcar 100 depends, in part, on the construction of side walls 110, roof 120, floor 130, end walls 140, and doors 170. The present invention provides a method for increasing the thermal efficiency of a cargo container, such as boxcar 100, by attaching insulated panels to the exterior surfaces of the cargo container and, in one implementation, by modifying floor 130. For example, in one implementation, insulated panels are attached to one or more of the exterior surfaces of side walls 110, roof 120, end walls 140, and doors 170. In some cases, however, insulation may also be applied to the interior side of the doors. These implementations are merely exemplary and other implementations may also be used.
FIG. 2 is a perspective view of an insulated panel consistent with one embodiment of the invention. As discussed above, insulated panels will be attached to exterior surfaces of boxcar 100 to improve the thermal efficiency of boxcar 100. As shown in FIG. 2, in one implementation, an insulated panel 200 is constructed of an outer skin 210 located on at least one face of an insulating layer 220. In the implementation of FIG. 2, outer skin 210 is located on opposing faces of insulating layer 220. These implementations are merely exemplary, and other implementations may also be used including having multiple and different types of outer skins.
In one implementation, the outer skin 210 is constructed of galvanized steel, aluminum, stainless steel, fiber-reinforced plastics, removable plastic films or some combination of these materials. Because insulated panel 200 will be attached to an existing surface that provides structural support to the boxcar, insulated panel 200 need not be constructed of materials capable of providing such support. Therefore, in another implementation, lighter and more thermally efficient composite materials may be used to form outer skin 210. These implementations are merely exemplary, and other implementations may also be used.
Insulating layer 220 may be constructed from any insulating material that will increase the thermal efficiency of the insulating panel 200. In one implementation, insulating layer 220 comprises a closed-cell polymer foam, such as urethane. In another implementation, insulating layer 220 comprises a vacuum insulated panel. Vacuum insulated panels are constructed of an intermediate film or laminate providing a barrier to passage of air into an interior porous insulating material that has been evacuated to increase its insulating value. In one implementation, the interior porous insulating material comprises a micro-cellular open-cell foam core material. In one implementation, the diameter of the cells is on the order of 10⁻⁶in. A one inch thick sheet of such a material may have a R-value (evacuated) of approximately 28. A micro-cellular, open-cell polystyrene foam, such as Instill™ available from Dow Chemicals may be used in such an implementation. In yet another implementation, the porous insulating material is a fine fiberglass web core material. In one implementation, each fine fiberglass strand will have a diameter of approximately 0.001 in. A one inch thick sheet of such a material may have a R-value (evacuated) of approximately 40. A fine fiberglass web core material such as Threshold™ available from Thermal Visions may be used in such an implementation. In another implementation, insulation layer 220 comprises a combination of foam and vacuum insulated panels. These implementations are merely exemplary, and other implementations may be used.
As indicated above, insulated panels are intended for installation on the exterior surfaces of the boxcar. Therefore, in one implementation, insulated panels are constructed in a shape such that they may be overlaid on the exterior surfaces of the sidewalls of a boxcar. For example, as shown in FIG. 1A, side walls 110 of boxcar 100 contains protrusions, such as protrusion 180 on boxcar 100. Therefore, in one implementation, insulated panels include indentations so that insulated panels can fit over the protrusions on the exterior portion of the boxcar. Insulated panels may be constructed from any of several well-known methods. In one implementation, insulated panels will be constructed using composite extrusion to create a single panel. These implementations are merely exemplary, and other implementations may also be used.
The insulated panels may be applied to boxcar 100 using any of several well-known application methods. In one implementation, insulated panels will be applied to boxcar 100 using a structural adhesive, such as Pliogrip 7700 available from Ashland Specialty Chemical Company. In another implementation, mechanical fasteners or welding may be used. In yet another implementation, a combination of adhesives and mechanical fasteners may be used. These implementations are merely exemplary, and other implementations may also be used.
FIG. 3 is a perspective view of a boxcar with insulated panels installed consistent with one embodiment of the invention. As shown in FIG. 3, in one implementation, side wall insulated panels 300, roof insulated panels 310, end wall insulated panels 320, and door insulated panels 330 are applied to the exterior of boxcar 350 to improve the thermal efficiency of boxcar 350. Side wall insulated panels 300, roof insulated panels 310, end wall insulated panels 320, and door insulated panels 330 are insulated panels of the construction described above and are designed to fit over the exterior surfaces of the side walls, roof, end walls, and doors respectively. In addition, side wall insulated panels 300, roof insulated panels 310, end wall insulated panels 320, and door insulated panels 330 are attached to boxcar 350 using one of the methods described above. Any number of insulated panels may be applied to a boxcar including any combination of side wall insulated panels 300, roof insulated panels 310, end wall insulated panels 320, and door insulated panels 330. These implementations are merely exemplary, and other implementations may also be used.
In one implementation, corner pieces may also be used at the intersection of various insulated panels. Corner pieces may be made of FRP composites or any other suitable material which are designed to fit at the intersection of other composite panels. Insulation may be added to the corner piece or flashing. As here embodied and shown in FIG. 3, corner pieces 340 may be installed at the intersection of a side wall insulated panel 300 and a roof insulated panel 310 or at the intersection of a side wall insulated panel 300 with an end wall insulated panel 310. In one implementation, corner pieces may be connected to the other insulated panels using one of the methods described below. These implementations are merely exemplary, and other implementations may also be used.
In one implementation, if multiple insulated panels are used, the insulated panels will interconnect with one another. In another implementation, the insulated panels will interconnect to form a single structure. Any suitable method of interconnecting the insulated panels may be used, such as adhesives, mechanical fasteners, or welding. In one implementation, the insulated panels may be connected prior to application of the panels to the boxcar. In another implementation, the insulated panels may be connected when during application of the panels to the boxcar. These implementations are merely exemplary, and other implementations may also be used.
In one implementation, insulated panels will be interconnected using a connector such as that disclosed in U.S. Pat. No. 3,353,314, the disclosure of which is expressly incorporated herein. FIG. 4A illustrates two insulated panels with connectors of this type consistent with one embodiment of the invention. As shown in FIG. 4A, in one implementation, insulated panels 400 and 410 have slots 412 and 414 and 416 and 418, respectively. Slots 412, 414, 416, and 418 are positioned on the edges of insulated panels 400 and 410 such that when insulated panels 400 and 410 are aligned with one another, slots 412 and 416 are approximately aligned and slots 414 and 418 are approximately aligned. In this implementation, each edge of a insulated panel has two slots, however, any number of slots may be used. In this implementation, each pair of aligned slots includes a mechanism to connect insulated panel 400 to insulated panel 410. This mechanism is further described in FIG. 4B. This implementation is merely exemplary, and other implementations may also be used.
FIG. 4B is a cut-away illustration of a portion of two insulated panels consistent with one embodiment of the invention. As shown in FIG. 4B, in one implementation, slot 416 includes a hook 422 and corresponding slot 412 includes a pin 424. In order to connect two insulated panels, hook 422 engages pin 424. In one implementation, hook 422 is joined to a rod 426. Rotation of rod 426 allows hook 422 to be rotated so as to either engage with pin 424 or disengage from pin 424. In this implementation, rod 426 extends through outer skin 430 of the insulated panel, as shown in FIG. 4A. This design allows hook 422 to be rotated without having to access the interior of the insulated panel. In one implementation, rod 426 is designed such that it can be turned with a wrench. These implementations are merely exemplary, and other implementations may also be used.
In another implementation, the insulated panels will be connected using a clip. In this implementation, each insulated panel will include either a clip or a slot to receive the clip. In order to connect the insulated panels, the clip will slide into the slot and lock into place. Any suitable clip may be used in this implementation. This implementation is merely exemplary, and other implementations may also be used.
In one implementation, all insulated panels attached to the exterior of a boxcar will include a connector such as that shown in FIG. 4A-4B. In this implementation, the connection of all the insulated panels will result in the panels forming a single structure. This implementation is merely exemplary, and other implementations may also be used.
Where the cargo container may not be readily insulated by adding a panel to an exterior surface, such as the floor of a boxcar, the interior may also be modified to improve the thermal efficiency of the boxcar without significantly reducing the interior dimensions of the boxcar. In one implementation, the interior of the floor of the boxcar may be modified to improve the thermal efficiency.
FIG. 5 illustrates a modified floor consistent with one embodiment of the invention. As shown in FIG. 5, insulated floor 500 includes an underframe 510, which would typically be the existing underframe of the boxcar. Underframe 510 may also include structural members, such as center sill 530, side sills 520, or stringers (not shown).
In order to improve the thermal efficiency of the floor 500, a liner 537 is first applied to underframe 510 of a boxcar. Liner 537 may be constructed of sheet material of wood, polymers, metal or laminates and combinations thereof. In one implementation, sheet steel is used. In one implementation, the dimensions of liner 537 will be substantially the same as the length and width of the boxcar. Liner 537 may be attached to underframe 510 using any suitable method, such as adhesives, fasteners, or welding. These implementations are merely exemplary, and other implementations may also be used.
In this implementation, composite structural members 540 are then installed on the top surface of liner 537. In one implementation, as shown in FIG. 5, composite structural members 540 are fiber reinforced polymer structures having a square cross section that extend substantially the length of the boxcar. Composite structural members 540 may be applied to liner 537 using any suitable method, such as adhesives or fasteners. In one implementation, a structural adhesive, such as Pliogrip 7700 available from Ashland Specialty Chemical Company is used. This implementation is merely exemplary, and other implementations may also be used.
In this implementation, as shown in FIG. 5, insulation 570 is then installed on liner 537 in the areas between composite structural members 540. In one implementation, insulation 570 is urethane foam. In another implementation, insulation 570 is a vacuum insulated panel, such as those described above. In still another implementation, insulation 570 includes a combination of urethane foam and vacuum insulated panels. These implementations are merely exemplary and other implementations may also be used.
In this implementation, a top plate 550 is then applied on top of the composite structural members 540. Top plate 550 may be constructed of sheet material of wood, polymers, metal or laminates and combinations thereof. In one implementation, as shown in FIG. 5, supports 535 may also be included to provide additional support for top plate 550. In this implementation, supports 535 may be attached to side sills 520. This implementation is merely exemplary and other implementations may also be used.
In one implementation, top plate 550 forms the floor of the boxcar. In another implementation, as shown in FIG. 5, a nailable floor 560 is applied on top plate 550. Nailable floor 560 is floor constructed in such a manner that nails may be driven into the floor to attach cargo to the floor. Nailable floor 560 may be constructed of wood, polymers, metal or laminates and combinations thereof. These implementations are merely exemplary and other implementations may also be used.
It should be understood that the result of modifying a boxcar as described above including the use of insulated panels on the exterior of the car and modifying the floor will improve the thermal efficiency of the boxcar. It should also be understood that the increase in these insulating properties has been achieved without having to construct an entirely new boxcar. As indicated above, the method of the invention may be applied to other cargo containers, besides boxcars.
Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the invention being indicated by the following claims.

Claims

1. A cargo container comprising:

an underframe having a top and bottom surface;

a floor connected to the top surface of the underframe;

first and second side walls having exterior surfaces;

first and second end walls having exterior surfaces,

a roof having an exterior surface, the underframe, floor, first and second side walls; first and second end walls, and roof being connect to form an enclosure; and

at least one insulating panel comprising an insulating layer and at least one outer skin located on at least one face of the insulating layer, the at least one insulating panel located on the exterior surface of at least one of the first side wall, second side wall, first end wall, second end wall, or roof.

2. The cargo container of claim 1, wherein the at least one outer skin of the at least one insulating panel comprises fiber-reinforced plastics and wherein the insulating layer comprises urethane foam.

3. The cargo container of claim 1, wherein the at least one outer skin of the at least one insulating panel comprises metal and wherein the insulating layer comprises urethane foam.

4. The cargo container of claim 1, wherein the at least one outer skin of the at least one insulating panel comprises fiber-reinforced plastics and wherein the insulating layer comprises a vacuum insulated panel.

5. The cargo container of claim 1, wherein the at least one outer skin of the at least one insulating panel comprises metal and wherein the insulating layer comprises a vacuum insulated panel.

6. The cargo container of claim 1, wherein the at least one insulating panel substantially covers the exterior surface of the side wall, end wall, or roof to which it is applied.

7. The cargo container of claim 1, further comprising:

at least one corner piece joining the at least one insulating panel located on the exterior surface of the first side wall, second side wall, first end wall, second end wall, or roof to a second insulating panel located on the exterior surface of an adjacent generally perpendicularly disposed side wall, end wall, or roof.

8. The cargo container of claim 7, wherein the at least one insulating panel and the at least one corner piece substantially cover the exterior surfaces of the first side wall, second side wall, first end wall, second end wall, and roof.

9. The cargo container of claim 1,

wherein at least two insulating panels are located on the exterior surfaces of the first side wall, second side wall, first end wall, second end wall, and roof; and wherein

each insulating panel is connected to at least one other insulating panel located on the same exterior surface.

10. The cargo container of claim 9, wherein each insulating panel comprises a latch designed to engage a catch on another insulating panel and a catch to be engaged by a latch on another insulating panel.

11. The cargo container of claim 1, further comprising:

at least one insulating member located between the underframe and the floor.

12. A cargo container comprising:

an underframe having a top and bottom surface;

a liner having a top surface and located on the top surface of the underframe;

a floor located on the top surface of the liner;

first and second side walls having exterior surfaces;

first and second end walls having exterior surfaces,

a roof having an exterior surface, the underframe, floor, first and second side walls; first and second end walls, and roof being connected to form an enclosure; and

at least one insulating panel comprising an insulating layer and at least one outer skin located on at least one face of the insulating layer, the at least one insulating panel being located on the exterior surface of at least one of the first side wall, second side wall, first end wall, second end wall, or roof.

13. The cargo container of claim 12, further comprising:

at least one insulating member located between the liner and the floor.

14. The cargo container of claim 13, further comprising:

at least two insulating members located between the liner and the floor; and

a layer of insulation on the liner in an area between the at least two insulating members.

15. The cargo container of claim 13, wherein the floor is constructed of a nailable material.

16. The cargo container of claim 13, wherein the at least one outer skin of the at least one insulating panel comprises fiber-reinforced plastics and wherein the insulating layer comprises urethane foam.

17. The cargo container of claim 13, wherein the at least one outer skin of the at least one insulating panel comprises metal and wherein the insulating layer comprises urethane foam.

18. The cargo container of claim 13, wherein the at least one outer skin of the at least one insulating panel comprises fiber-reinforced plastics and wherein the insulating layer comprises a vacuum insulated panel.

19. The cargo container of claim 13, wherein the at least one outer skin of the at least one insulating panel comprises metal and wherein the insulating layer comprises a vacuum insulated panel.

20. A cargo container comprising:

an underframe having a top and bottom surface;

a liner having a top surface and located on the top surface of the underframe;

at least one insulating member on the top surface of the liner;

a floor located on the at least one insulating member;

first and second side walls having exterior surfaces;

first and second end walls having exterior surfaces,

at least two insulating panels comprising an insulating layer and at least one outer skin located on at least one face of the insulating layer, the at least two insulating panels being located on the exterior surface of at least one of the first side wall, second side wall, first end wall, second end wall, or roof;

wherein each insulating panel is connected to at least one other insulating panel located on the same exterior surface.