Abstract:
A method for reducing air leakage from a refrigerated container includes positioning at least one inflatable device about a rear end of the refrigerated container; coupling the at least one inflatable device to one end of an elongated duct located within an interior space of the refrigerated container; coupling a second end of the elongated duct to an outlet port of the evaporator fan; circulating, via the evaporator fan, air through the interior space; and extracting the circulated air through the elongated duct and into the at least one inflatable device.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This Application is a National Stage of International Application No. PCT/US13/020017 filed Jan. 3, 2013, which claims the benefit of U.S. provisional application, Application No. 61/583318, filed Jan. 5, 2012, which is herein incorporated by reference. 
       FIELD OF INVENTION 
       [0002]    This invention relates generally to a transport refrigeration system and, more particularly, to an inflatable seal or flexible tube that is disposed on, around, or near the rear door opening of a refrigerated shipping container or trailer for providing a seal against leakage and is inflated with air from an evaporator fan of the transport refrigerated system. 
       DESCRIPTION OF RELATED ART 
       [0003]    Products such as produce, meat and the like being shipped relatively long distances are conventionally placed within refrigerated containers. These refrigerated containers are specifically designed for conditioning an interior space with refrigerated air for an extended period of time. These refrigerated containers utilize a transport refrigeration unit for cooling these products with refrigerated air during transport. The refrigeration unit is typically secured to the front wall of the refrigerated container and circulates cooled air inside the interior space through evaporator fans, which direct the air from the front of the container to the rear. 
         [0004]    Typically, insulation and air leakage is a concern when shipping produce and/or meats in these refrigerated containers. An area of concern is the rear door as it tends to be furthest away from the refrigeration cooling unit, which is located at the front of the refrigerated container. In some cases, seals and hinges on the rear door wear out over time causing the refrigerated air to leak out and prevent produce or meat at the rear door from being maintained at an optimal temperature. This air leakage tends to increase the rate of spoilage of the produce or meats. Additionally, air leakage can interfere with controlling the refrigeration unit and/or change the humidity of the controlled atmosphere surrounding the area of the leak by changing percentages of gas components in its vicinity such as, for example, the percentage of nitrogen in the area of the leak. 
       BRIEF SUMMARY 
       [0005]    According to one aspect of the invention, an air sealing system for a refrigerated container, includes an evaporator fan configured for circulating air flow through an interior space of the refrigerated container; an inflatable device that is flexible and is configured to be positioned about a rear end of the refrigerated container; and an elongated duct coupled at a first end to the inflatable device and a second end to an outlet port of the evaporator fan, the elongated duct being configured for extracting the circulated air flow and communicating the extracted air flow into the inflatable device. 
         [0006]    According to another aspect of the invention, a method for reducing air leakage from a refrigerated container includes positioning an inflatable device about a rear end of the refrigerated container; coupling the inflatable device to one end of an elongated duct located within an interior space of the refrigerated container; coupling a second end of the elongated duct to an outlet port of the evaporator fan; circulating, via the evaporator fan, air through the interior space; and providing a portion of the through the elongated duct and into the inflatable device. 
         [0007]    Other aspects, features, and techniques of the invention will become more apparent from the following description taken in conjunction with the drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         [0008]    Referring now to the drawings wherein like elements are numbered alike in the FIGURES: 
           [0009]      FIG. 1  illustrates a perspective view of an integrated container with a refrigeration system according to an embodiment of the invention; 
           [0010]      FIG. 2A  illustrates a schematic side view of the integrated container with an inflatable seal according to an embodiment of the invention; 
           [0011]      FIG. 2B  illustrates an elevation view of the inflatable seal shown in  FIG. 2A  but with the seal positioned around the rear door of the integrated container according to an embodiment of the invention; and 
           [0012]      FIG. 3  illustrates an elevation view of the inflatable seal but with the seal positioned in the sidewall around the rear door of the integrated container according to an embodiment of the invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0013]    Embodiments of an integrated refrigerated container include an inflatable device such as, for example, an inflatable seal or an inflatable flexible tube that is disposed on, around, or near the rear doors of a cargo container. In embodiments, the inflatable seal or flexible tube can be disposed in the sidewall of the refrigerated container around the rear door or inside the rear door along its perimeter. In an embodiment, the inflatable seal may be removable from the sidewall and be replaceable with another inflatable seal or be reusable with the same inflatable seal (i.e., the inflatable seal may be used one time or may be reusable). The inflatable seal or flexible tube may be connected to an elongated duct emanating from an outlet of an evaporator fan for bleeding air from the evaporator fan in order to selectively inflate the inflatable seal. Additionally, a check valve may be coupled to the inflatable seal or flexible tube that is in line with the elongated duct for preventing the inflatable seal or flexible tube from deflating when the evaporator fan is not running. The inflatable seal or flexible tube, once inflated, provides additional insulation of the interior space of the cargo container as well as forming a seal between the interior space and the rear doors in order to prevent or minimize refrigerated air from escaping out of the interior space into the ambient environment. 
         [0014]      FIG. 1  illustrates an example of an integrated refrigerated container  100  including a cargo container  105  coupled to a refrigeration system  110  for providing space cooling of the cargo container  105 . The cargo container  105 , which may be formed into a generally rectangular construction, and includes opposed side walls  115 , a front wall  120 , a top wall  125 , a directly opposed bottom wall  130 , and a door or doors (not shown) attached on hinges at the rear end  135 . The walls  115 - 130  may be formed, for example, from welded corrugated steel or aluminum to provide significant strength and structural integrity. In an example, the integrated refrigerated container  100  may be approximately twenty feet in length and a width and height of approximately eight feet. However, these dimensions may vary depending on the particular environment in which the integrated refrigerated container  100  is utilized. The cargo container  105  includes a front cavity  200  ( FIG. 2 ) at the front wall  120  for housing the components of the refrigeration system  110 , which is provided for cooling interior space  250  ( FIG. 2 ) enclosed by the walls  115 - 130 . 
         [0015]      FIGS. 2A-2B  illustrate an embodiment of the integrated refrigerated container  100  having an inflatable device such as, for example, an inflatable seal  255  that can be selectively inflated. The inflatable seal  255  may, in one example, be tubular and have a generally rectangular shape, and is fastened at or around the rear doors with hooks, pins, tape, hook and loop fasteners such as Velcro™ fasteners, or any other similar types of fasteners that facilitates ease of attachment to the container  100  or removal and replacement upon damage to the inflatable device. In another embodiment, an inflatable flexible tube (not shown) with a length that is bent to follow the perimeter of the interior walls can also be used without departing from the scope of the invention. In the example shown in  FIGS. 2A-2B , the inflatable seal  255  can be formed from a polyurethane material that is flexible and elastic in an inflated or deflated state. In other embodiment for example, the inflatable seal  255  can be made of any conventional film grade polymeric compositions, including polyolefins such as high density polyethylene, low density polyethylene, polypropylene and blends thereof, film grade vinyl polymer as well as natural polymeric material, high density polypropylene (HDPP), polyvinyl chloride (PVC), or the like that can be inflated with air pressure from that provided by the evaporator fan  235 . As shown in  FIGS. 2A-2B , the inflatable seal  255  includes an inlet port, which is coupled to a check valve  260  at one end. Also, the check valve  260  is configured to be coupled, at its second end, to an outlet of the evaporator fan  235  via an elongated duct  265 . The elongated duct  265  facilitates air flow from the evaporator fan  235  to be diverted through the duct  265  in order to inflate the inflatable seal  255 . In an embodiment, the check valve  260  may be a spring-loaded check valve having a ball coupled to an internal spring that allows flow of air in one direction via the spring-loaded ball although, in another example, a flap that opens under pressure may also be used. In an embodiment, the check valve  260  may include a release valve for manually deflating the inflatable seal  255 . In addition, it is contemplated that the release valve may be configured to automatically deflate the seal. In another embodiment, the inflatable seal  255  can be selectively deflated through a release valve coupled to the seal  255  that can be manually engaged in order to let air out of the interior of the seal  255 . The inflatable seal  255  may be positioned adjacent (e.g., at or around) the rear doors and be selectively inflated from its deflated state and expand along the interior walls of the cargo container  105  in order to maintain a seal along the perimeter of the internal walls at or near the rear doors (not shown) of the cargo container  105  while also increasing the insulation of the cargo container  105 . In an embodiment, the inflatable seal  255  can be sized according to the internal dimensions of the rear door (not shown) of the cargo container  105 . In an embodiment, the seal  255  may be removable from the sidewall of cargo container  105  and/or be replaceable upon damage (i.e., the inflatable seal may be used one time or may be reusable). In an embodiment, the inflatable seal  255  can include holes of a predetermined diameter along its surface in order to define the amount of air that is leaked from the seal  255  in an area around or near the rear door. This air leakage can provide refrigerated air or mixed gases at or around the rear door and supports cooling of the interior space  250  or controlled gas supply to the area at or around the rear door. The inflatable seal  255  can be attached to one or more interior walls of the cargo container  105  so as to prevent dislocation of the seal  255  during transport. 
         [0016]    Also shown in  FIG. 2A , the refrigeration system  110  may include an electrically driven refrigeration compressor  205  connected, via a refrigerant line  225 , to a condenser coil  215 , a condenser blower  210 , an expansion valve  210 , an evaporator coil  230  and the evaporator fan  235 . The compressor  205 , condenser coil  215 , condenser fan  210 , and expansion valve  210  are positioned in the front cavity  200 , which is exposed to the external ambient environment. Also, the compressor  205 , condenser coil  215 , condenser fan  210 , and expansion valve  210  are separated from the interior space  250  by an insulating wall  202 , while the evaporator fan  235  and the evaporator coil  230  are located within the interior space  250 . The evaporator fan  235  cooperates with the evaporator coil  230  to refrigerate the air within the interior space  250  by circulating air flow over the evaporator coil  230  along paths  240 ,  245 . Additionally, the evaporator fan  235  circulates air flow through the elongated duct  265  in order to inflate the inflatable seal  255  and increase the insulation of the cargo container  205  as well as form a seal between the rear end  135  ( FIG. 1 ) and the rear doors (not shown). During operation of the refrigeration system  100 , the elongated duct  265  routes air from the evaporator fan  235  into the inflatable seal  255  when the evaporator fan  235  is circulating air through the interior space  250 . Further, the check valve  260  causes the inflatable seal  255  to maintain its inflated state by preventing air from escaping out of the inflatable seal  255  when the evaporator fan  235  is not circulating air through the elongated duct  265  such as, for example, when the evaporator fan  235  cycles to “low speed” or is off. 
         [0017]    As shown in  FIG. 2B , the inflatable seal  255  is configured for being positioned at or near the rear doors  305 ,  310  at rear end  135  and be selectively inflated by airflow flowing through the elongated duct  265  that is bled from evaporator fan  235 . The inflatable seal  255 , once inflated, expands along the interior walls of the cargo container  105  and maintains a seal with the rear doors  305 ,  310  along the perimeter of the internal walls at or near the rear doors  305 ,  310  of the cargo container  105  while also increasing the insulation of the cargo container  105 . In another embodiment, additional ducts  270 ,  275  can be provided at or around the rear doors  305 ,  310  for inflating additional flexible tubes or seals. In another embodiment, cargo container  105  may include two seals (not shown), substantially similar to seal  255 , positioned about each of the rear doors  305 ,  310 . In another embodiment, the two seals positioned about each rear door  305 ,  310  may be located in a deflated condition and stored within a cavity in the respective doors  305 ,  310  in order to protect the seals from puncture. Upon inflation, the seals would extend from the door  305 ,  310 . It is to be appreciated that the inflatable seal  255  can facilitate ease of opening the rear doors from their closed position by reducing the vacuum formed by the cold refrigerated air within interior space  250 . 
         [0018]    In an example, illustrated in  FIG. 3 , an inflatable device such as, for example, an inflatable seal  305  is incorporated into the walls of the refrigerated container  300  according to an embodiment of the invention. Particularly, the inflatable seal  305  is positioned at or near doors  310 ,  315  and is incorporated between an exterior sheet metal panel (not shown) that is adjacent to the ambient environment  325 , and an interior liner  320 , adjacent to the interior space  350  being conditioned, while all other aspects remain substantially the same as those of integrated refrigerated container  100  that is shown and illustrated in  FIGS. 1-2B . The inflatable seal  305  is configured to be selectively inflated by refrigerated air flowing through an elongated duct (not shown) that is bled from an evaporator fan (not shown). The inflatable seal  305 , once inflated, expands outwardly towards the rear doors  310 ,  315  and maintains a seal along the perimeter of around or near the rear doors  305 ,  310  when the rear doors  305 ,  310  are closed. 
         [0019]    The technical effects and benefits of embodiments relate to an inflatable seal that is located at or near the rear doors of a cargo container. The inflatable seal includes an elongated duct connected to the outlet of an evaporator fan for bleeding air from the evaporator fan in order to inflate the inflatable duct. Additionally, a check valve coupled to the inflatable seal and in line with the elongated duct prevents the inflatable duct from deflating when the evaporator fan cycles to low speed or is off 
         [0020]    The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. While the description of the present invention has been presented for purposes of illustration and description, it is not intended to be exhaustive or limited to the invention in the form disclosed. Many modifications, variations, alterations, substitutions, or equivalent arrangement not hereto described will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the invention. Additionally, while various embodiment 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.