Abstract:
Shipping containers, and more particularly insulated shipping containers, for holding temperature sensitive products and coolant in a predetermined relationship to maintain a refrigerated or frozen condition for an extended period of time. Containers of this type can be molded from rigid polyurethane foam or other materials for shipping or transporting products such as biological and similar products which need to be maintained at 2° to 8° Centigrade or frozen. Specific constructions are shown and described.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
   The present application is a continuation of application U.S. patent application Ser. No. 10/886,310 filed Jul. 7, 2004 now U.S. Pat. No. 7,028,504, which claims priority from U.S. provisional patent application Ser. No. 60/485,484 filed Jul. 7, 2003, the disclosure of which is fully incorporated herein by reference. 

   FIELD OF THE INVENTION 
   The present invention relates to shipping containers, and more particularly to insulated shipping containers for holding temperature sensitive products and coolant in a predetermined relationship to maintain a refrigerated or frozen condition for an extended period of time. For example, containers of this type are molded from rigid polyurethane foam or other materials for shipping or transporting products such as biological and similar products which need to be maintained at 2° to 8° Centigrade or frozen. 
   BACKGROUND OF THE INVENTION 
   Various type of shipping containers have been developed including conventional cardboard cartons having an insulating material therein that may be formed into a desired shape or may comprise panels or the like. Generally, a coolant such as packaged ice, gel-packs or loose dry ice is placed around the product in a cavity to refrigerate the product during shipping. 
   With regard to shipping particularly sensitive products, such as certain medical or pharmaceutical products, rigid polyurethane containers often are used because of the superior thermal properties. Conventional insulated shipping containers have many problems, particularly when shipping temperature sensitive products for extended periods of time, such as when products are shipped internationally. These containers, especially modular liner systems, often include a number of seams in the insulating material through which air can enter and heat the cavity in the carton. In addition, the cavity often includes airspaces around the product and coolant which can facilitate but not control convection, especially if the insulating material includes leaking seams. Unfortunately, temperature gradients or zones are created. These conditions may accelerate the melting of the coolant, consequently shortening the time that the container can maintain a refrigerated condition. In addition, the cover may be formed from different material, such as polyester foam which may have a thermal resistance substantially lower than the body itself and thus may compromise the performance of the container. 
   Furthermore, the product and coolant typically are placed together within the cavity in a carton, which may have adverse effects. When shipping certain products it may be desired to refrigerate but not freeze the product. Placing a coolant, such as loose blocks of dry ice, into a cavity against the product may inadvertently freeze and damage the product. Even if held away from the product, the coolant may shift in the cavity during shipping, especially as it melts and shrinks in size, inadvertently contacting the product. In addition, melted coolant may leak from its container, possibly creating a mess within the cavity or even contaminating the product being shipped. 
   Some suitable solutions to some of the foregoing problems have been developed in the past such as shown and described in U.S. Pat. No. 5,924,302. Still, there are needs for containers particularly for shipping a large amount of product for long periods of time. 
   SUMMARY OF THE INVENTION 
   The concepts of the present invention are directed to new and improved containers for shipping temperature sensitive products in a refrigerated and/or frozen condition for an extended period of time. 
   In accordance with the present invention, several embodiments of containers constructed of, for example; rigid polyurethane foam are described and shown herein and which are particularly useful for, among other purposes, small and large shipments, such as via air freight, including via LD3 shipping containers. Importantly, containers according to the present invention are basically formed of a bottom, preferably with a tray for holding product, four sides, and a lid, and preferably with a coolant tray. Furthermore, the bottom, sides and lid are designed to interlock (the sides and base preferably are slide locked or are tongue and grooved, as versus typical 45 degree corners that do not lock together or “grip” together), so as to reduce thermal convection. Also, preferably a rigid polyurethane foam is molded to form a bottom for the container and can have “pallet” grooves as distinguished from using wood which can invite termite problems, particularly in an air freight environment. The coolant tray preferably is a slide-in tray which contains a suitable coolant such as dry ice or gel packs, and which also is preferably made of rigid polyurethane foam and to maintain the coolant out of direct contact with the product. In addition, the interior walls and bottom of the container can be configured to provide a convection design to create a controlled air flow within the product compartment, and this air flow can reduce the temperature gradient within the product compartment and thus provide better and even temperature control when shipping biological and other products. 
   Thus, according to the concepts of the present invention, the containers can have gripping walls, particularly on larger containers, to reduce thermal convection between the outside environment and the internal environment. The sliding coolant tray can take any of many forms and/or shapes and is used to regulate the temperature between the coolant and the product. The interior walls of the sides, bottom, and top preferably are designed to provide convection and thus create a controlled air flow within the product compartment to control and reduce the temperature gradient within the product compartment, and thereby provide better control when shipping biological and other products. For example, the walls, bottom, and/or top can have shapes, such as grooves and/or protrusions, molded therein to provide convection and thus coolant air flow around the product load. Also, the side walls can have a shape such as a V or U shape or some variant thereof to provide “convection walls” on two sides, and coolant on the other two sides. Furthermore, a coolant tray can include a central pillar molded into the tray to keep the cooling effect of the coolant controlled in the center of the product load. Thus, containers according to the present invention provide control of thermal convection via predesigned air flow by the design of sides, grooves and the like to minimize the temperature gradient in the product load and in an attempt to maintain the same temperature at the corners, middle and at all areas of the product load. The gripping connection between the sides and base aid in controlling thermal conduction and convection from the outside to the inside of the container. The base is designed to maintain the product load off of the actual bottom of the container and is provided with air channels to allow internal air to circulate all around the load. The base for large containers is designed preferably to transport pallet loads of products such as biological products. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a view of a large insulated container according to the present invention; 
       FIG. 2  is an exploded view of the container of  FIG. 1 ; 
       FIG. 3   a  is an exploded view of a partially assembled container of  FIG. 1 , and  FIGS. 3   b – 3   d  are detailed views of components thereof; 
       FIG. 4  is a view illustrating the open top of the container and a coolant tray having a conduction block, and gel packs; 
       FIGS. 5   a  through  5   e ; further illustrate the assembly of a container similar to that of  FIG. 1  for assembling the container about a cryogenic vessel; 
       FIGS. 6   a  through  6   c  illustrate an alternative container having a pair of V-shaped sides and grooves to facilitate circulation of cold air all around a product load to be disposed in the middle of the container, and 
       FIG. 7  is a perspective view of another embodiment. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Turning now to the drawings,  FIG. 1  illustrates one embodiment of an insulated container  10  according to the present invention. It preferably is constructed of water-based rigid polyurethane foam with sides  12 , back of front  13 , bottom  14  and lid or top  15  all with an interlocking design for easy storage and assembly, and, for reduction of convection. 
   Turning to the exploded view of  FIG. 2 , a temperature range, for example, of 0° C. to 10° C. can be maintained by the use of an upper ice tray  16  to hold the necessary coolant  17  for the product load  18  in the container. The tray  16  can preferably be slid in on top of the product  18 . An internal product tray  20  with built up sides  20   a  can be provided to insulate the bottom of the product load  18  from the bottom or base  14  and reduce the temperature gradient within the container. The bottom  14  of the container can include forklift grooves molded into the bottom thereof for eliminating the need for a separate wooden pallet. It is desirable to eliminate wooden pallets and other wooden components because of the termite problem involved with air freight and elsewhere. The container shown in  FIG. 1  can be any desired size and can be sized to fit the standard LD3 shipping container to optimize the payload. 
   Turning now to the particular interlocking structure of the present container  10 ,  FIGS. 2 and 3   a – 3   d  particularly illustrate the interlocking structure of the sides, back, front, top and bottom. The sides  12  have tongues  12   a  on the upper end thereof, vertical elongated slots  12   b  at the outer edges of the inside, and a slot  12   c  at the bottom as best seen in  FIGS. 2 and 3   a – 3   b . On the other hand, the back and front have top and bottom tongues  13   a  and side tongues  13   b  as best seen in  FIG. 2 . The back and front sections  13  fit with the side sections  12  by the tongues  13   b  of the back and front sections sliding into respective elongated grooves  12   b  in the sides  12 . This allows the back and front  13  to slide into the slots  12   b  of the sides  12  in a simple manner to provide a very tight and rigid front, back and side structure, three components of which are illustrated interlocked in  FIG. 3   a  (the front has not yet been added). The bottom  14  has elongated slots  14   a  for receiving the lower tongues  13   a  of the front and back sections  13 , and further has elongated tongues  14   b  for mating with the bottom slots  12   c  of the sides  12 . The lid or top  15  has elongated slots  15   a  (see  FIG. 3   d ) for receiving the tongues  12   a  of the sides  12  and the tongues  13   a  of the back and front sections  13 . This tongue and groove construction is particularly important in providing “gripping walls” to reduce the thermal convection between the outside environment and the internal environment of the container  10 . They provide a positive interlocking of the four sides with the base and lid in accomplishing this task. 
   It is important that the coolant  17  not be in direct contact with the product load  18 . The sliding coolant tray  16  provides this insulation or buffering function, and grooves  12   d  in the sides, grooves  13   d  in the back and front sections  13 , provide a predesigned downward air flow in the side grooves around the product load via thermal convection to minimize temperature gradient within the product load. Similar grooves  16   b  in the coolant tray  16  cooperate in this regard. Also, similar grooves can be provided in the base  14  or product tray  20 , if desired. 
   Importantly, a pillar  16   a  in the center of the sliding tray  16  preferably is provided and extends vertically upwardly as best seen in  FIGS. 2 and 4 , and is particularly important from a thermal conduction standpoint to reduce the coolant conduction down into the center of the product load  18  that would occur if the coolant  17  was disposed in the location of the pillar  16   a . It has been found that without the pillar  16   a , the center of the product load  18  becomes too cool, and this pillar  16   a  of foam reduces the temperature of the normally very cold center portion of the load to help maintain an even product temperature. Preferably spacers  16   c  are provided within the ice tray  16  to help hold the ice packs  17  in place. Furthermore, these spacers  16   c  may have holes therethrough to allow air flow freely within the ice pack  17 . This arrangement and construction increases the thermal efficiency of the ice pack. 
     FIGS. 5   a  through  5   e  illustrate the assembly of an alternative container commencing with a base  42  on to which a product tank  40  is loaded as shown in  FIG. 5   a . Four inner walls  46  are inserted into the base  42 , and then side female outer walls  48   a  are inserted into the base ( FIG. 5   b ), followed by a pair of male outer walls  48   b  ( FIG. 5   c ). The outer walls, base and top can be tongue and groove construction as in the earlier Figures. The space  44  between the inner walls  46  and the outer walls  48  is filled with the dry ice pellets (not shown). A tongue and groove structure similar to those discussed above is used. Then, a thick, such as four inches think, die cut foam pad  50  is inserted into in the outer walls  48  ( FIG. 5   d ) in the product cavity to reduce the tendency for tall product to “tip” and fall, followed by the application of a snugly fit lid  52  ( FIG. 5   e ). The thus constructed container preferably is inserted into a corrugated box and taped closed. 
   Turning now to  FIGS. 6   a  through  6   c , the same illustrate another container embodiment of rigid polyurethane foam and which is designed to create an air flow within the product compartment for reducing the temperature gradient within the product compartment and thus providing better control when shipping biological products. This embodiment includes, as seen in  FIG. 6 , right and left sides  80  and front and back sides  82 , along with a base or bottom  83 . Of particular importance in this container design are the inside right and left side walls  86  which in this embodiment are V-shaped, but could be U-shaped, channeled or another suitable curved configuration. The purpose is to provide an air space between these inside side walls  86  and a stack of product (not shown) disposed in the cavity provided between inside walls  86  and upstanding barrier walls  88  which create air currents. The insides of the front and back walls  82  along with the outer sides of the barriers  88  form coolant cavities  90  for coolant which is typically gel ice. The barriers  88  can be spaced as shown or each can be a solid wall. The base  83  has raised areas  84   a  forming grooves  84   b  between the areas  84   a  so as to provide some air space at the base. The combination of the V-shaped inside walls  86 , grooves  84   b  in the bottom and similar grooves in a lid if desired (not shown) allow cool air flow by convection within the product compartment  92 . As with the other embodiments, the container shown in  FIG. 6  preferably is formed of rigid polyurethane foam. 
   The embodiment of  FIG. 6   a  has a relatively large product compartment  92 , whereas the embodiment of  FIG. 6   b  has a smaller product compartment  92   a , but otherwise the V wall and groove construction is similar. It has raised areas  84   a  forming grooves  84   b  like in  FIG. 6   a , the embodiment of  FIG. 6   c  is like that of  FIG. 6   a  but further includes a slide-in product tray  96 . The  FIG. 6  embodiments can use tongue and groove walls, base and top if desired. 
     FIG. 7  illustrates another embodiment particularly for use with a product container having a cap on top. The overall container  100  is similar to other embodiments and includes a lower pad  102  and lid  106 . A foam ice tray  104  is configured to fit on the cap of a product container to provide a consistent insulation barrier. Side areas  104   a  and  104   b  form trays for the coolant (not shown) on each side of the upstanding central section  104   c . The tray  104  also includes notches  104   d  for improved air flow. The central section  104   c  is a conduction block like  16   a  of  FIG. 4  to control the temperature in the central area. The walls, base and top also can be tongue and groove construction. 
   Thus has been described in an improved shipping container for maintaining a refrigerated or frozen condition for an extended period of time for a product contained therein. The particular features of importance are the slide-in ice tray  16  (for coolant  17 ) which can be slid into the container once the product  18  is disposed therein. Another particularly important feature is the interlocking walls, lid and base for controlling thermal convection between the external environment and the internal atmosphere. A further important feature is the pre-design shapes, cavities and channels in various places throughout the container to use thermal convection in moving and dispersing energy more evenly within the container. The same maximizes the release of energy from the coolant as well as reduces temperature gradients within the container&#39;s internal atmosphere. Furthermore, the provision of a pre-molded conduction block for reducing temperature pockets within the container by protecting specific places within the container from direct contact with coolants, particularly the center. This barrier uses the properties of thermal conduction to consume energy from the coolant source before it reaches the product load. The pre-molded shape and size of the barrier can be designed to allow only the desired amount of energy through while remaining stable and constant throughout the duration of transport. 
   Various changes, modifications, variations, as well as other uses and applications of the subject invention may become apparent to those skilled in the art after considering this specification together with the accompanying drawings and claims. All such changes, modifications, variations, and other uses and applications which do not depart from the spirit and scope of the invention are intended to be covered hereby and limited only by the following claims.