Abstract:
A method for shipping cargo in an enclosed elongated cargo container van comprising the steps of: (a) loading the cargo in the boxes, (b) stacking the boxes within the container van, (c) disposing a baffle sheet horizontally across vertical channels disposed between the cargo boxes, (d) providing baffle sheet openings within the baffle sheet in a configuration calculated to provide a predetermined pressure gradient across the cargo load, and (e) commencing the circulation of a ventilating gas through the cargo load from the bottom of the cargo load to the top of the cargo load.

Description:
FIELD OF THE INVENTION 
     This invention relates generally to methods for shipping cargo where the cargo requires ventilation. More specifically, the invention relates to methods for shipping cargo requiring ventilation in enclosed containers, such as container vans. 
     BACKGROUND OF THE INVENTION 
     Various kinds of cargo is preferably shipped in the manner whereby the cargo is continuously ventilated by the circulation of ventilating gases. For example, where the cargo needs to be refrigerated, it is desirable to circulate chilled air throughout the cargo. Also, where the cargo consists of fresh produce, it is frequently desirable to circulate gaseous ripening agents and/or insecticides throughout the cargo. 
     Some produce, such as green bananas, emit gases as they ripen. Such gases tend to accumulate around the fruit. The gas generates additional heat which, in turn, tends to accelerate the ripening process (thereby causing the emission of additional gases). Accordingly, if the ripening gases are not sufficiently exhausted, the produce will ripen unduly rapidly and unevenly. Much of the produce may, thereby, become overripened and spoiled during shipment. 
     Most cargo is now shipped in container vans having approximately the size and shape of a conventional semi truck trailer. Shipment by such container vans is by far the most common method of shipping cargo on land, by sea and by rail. The popularity of shipping via container vans stems from the fact that such container vans can be conveniently loaded off-site from the transportation distribution center (harbor, railhead or truck distribution center) and transported all the way to the final destination via any one or more of several shipment modes (by sea, land or rail) without having to be unloaded and reloaded at each distribution center. Attempts to solve the need for ventilating certain cargo, therefore, revolves around methods of providing adequate ventilation within container vans. 
     The present industry standard for ventilating cargo within container vans is to place the cargo in boxes and to then stack the boxes, either individually or on pallet boards, within container vans having some form of perforated floor, such as a grating. After the cargo boxes are located into the container van, an attempt is made to circulate ventilation gases from the lower portion of the forward end wall of the container van, up through the perforated floor, and up through the boxes. The ventilation gases are then accumulated at the top of the container van and removed by a vacuum drawn at the upper portion of the forward wall. 
     This conventional method of ventilating container vans is not very effective. The problem is that once ventilating gases are injected into the floor of the container van at the forward end wall, the gases immediately begin rising up through cargo boxes at the forward end of the container van. Much of the ventilation gases passes rapidly around the boxes through vertical chambers formed in the loading process. Because so much of the ventilating gases leak upwardly through the vertical chambers at the forward end of the cargo load, little of the ventilation gases reaches the rearward end of the container van. 
     In U.S. Pat. Nos. 5,116,191 and 5,706,662, both of which are incorporated herein by this reference, two different methods are proposed to address the aforementioned problems. Both of these prior art methods, however, require the stacking of the cargo on pallet boards using special packing and retaining techniques, such that internal channels are generated within the cargo load. The use of such special stacking and retaining techniques, however, has not been well received in the industry. The industry continues to prefer to load boxes within container vans by simply stacking the boxes upon one another, either individually or on pallets, without having to employ the special stacking and retaining techniques. 
     Accordingly, there is a need for an improved method of shipping cargo requiring ventilation, which is adapted to the industry preference for avoiding special stacking and retaining techniques and which otherwise avoids the aforementioned problems in the prior art. 
     SUMMARY 
     The invention satisfies this need. The invention is a method for shipping cargo in an enclosed, elongated cargo container van. The invention comprises the steps of (a) loading the cargo into boxes having a pair of opposed vertical side walls, a pair of opposed vertical end walls, a top wall and a bottom wall, (b) disposing the boxes in a plurality of tiers within the cargo container to form a cargo load having a top side and a bottom side, the boxes being disposed within the cargo container such that boxes in the forward portion of the enclosed space are tightly packed proximate to the sidewalls and to the forward end wall, the boxes being disposed within the cargo container so as to provide a plurality of vertical channels spaced apart from the side walls and spaced apart from the forward end wall, the vertical channels each extending from the bottom of the cargo load to the top of the cargo load, (c) disposing a baffle sheet horizontally across each vertical channel, at least some of the baffle sheets having one or more baffle sheet openings to allow the passage of gas through the baffle sheet, the number of baffle sheet openings in each baffle sheet being chosen so as to provide for a predetermined pressure gradient above the cargo load when a gas is circulated through the cargo load from the bottom of the cargo load to the top of the cargo load, and (d) commencing the circulation of a gas through the cargo load from the bottom of the cargo load to the top of the cargo load. 
    
    
     DRAWINGS 
     These features, aspects and advantages of the present invention will become better understood with regard to the following description, appended claims and accompanying figures where: 
     FIG. 1 is an isometric view of a loading scheme for a cargo van of the prior art; 
     FIG. 2 is a cross-sectional side view of the cargo van illustrated in FIG. 1 showing the flow of ventilation gases through the cargo; 
     FIG. 3 is an isometric view of a cargo van employing the method of the invention; 
     FIG. 4 is a cross-sectional side view of the cargo van illustrated in FIG. 3 showing the flow of ventilation air through the cargo load; 
     FIG. 5 is a top view of the cargo load within the cargo van illustrated in FIG. 3; 
     FIG. 6 is a transverse sectional view of the cargo load illustrated in FIG. 5; 
     FIG. 7A is an isometric view of a baffle sheet useable in the method of the invention; 
     FIG. 7B is an isometric view of a second baffle sheet useable in the method of the invention; 
     FIG. 7C is an isometric view of a third baffle sheet useable in the method of the invention; 
     FIG. 7D is an isometric view of a fourth baffle sheet useable in the method of the invention; 
     FIG. 7E is an isometric view of a fifth baffle sheet useable in the method of the invention; 
     FIG. 7F is an isometric view of a sixth baffle sheet useable in the method of the invention; 
     FIG. 7G is an isometric view of a seventh baffle sheet useable in the method of the invention; 
     FIG. 8 is a top view of an alternative cargo load disposed within a cargo van; 
     FIG. 9 is an isometric view of a box useable in the cargo load illustrated in FIG. 8; 
     FIG. 10 is a transverse sectional view of the container load illustrated in FIG. 8; 
     FIG. 11 is a plan view of a pallet board load combination having features of the invention; 
     FIG. 12 is an end view of the pallet board load combination illustrated in FIG. 11; and 
     FIG. 13 is an isometric view of a large baffle useable in the invention. 
    
    
     DETAILED DESCRIPTION 
     The following discussion describes in detail one embodiment of the invention and several variations of that embodiment. This discussion should not be construed, however, as limiting the invention to those particular embodiments. Practitioners skilled in the art will recognize numerous other embodiments as well. 
     The invention is a method for shipping cargo in an enclosed elongated cargo container van  10 . A typical cargo container van  10  is illustrated in FIG.  1 . The cargo container van  10  comprises a pair of opposed side walls  12 , a forward end  14 , a rearward end  16 , a roof  18  and a floor  20 . The cooperation of these six walls forms an enclosed space  22  having a forward portion  24  and a rearward portion  26 . Typically, the floor  20  is perforated such as by being a “T” floor with an upper surface provided by a grating. The floor  20  is disposed above a horizontal ventilation channel  28 . 
     Within the container van  10  are disposed boxes  30  containing cargo requiring ventilation. The method of the invention is ideal where the cargo is produce such as green bananas. Where the produce comprises green bananas, the boxes  30  typically have a pair of opposed vertical side walls  32 , a pair of opposed vertical end walls  34 , a top wall  36  and a bottom wall (not shown). Each box  30  is typically 15 ½ inches wide, 20 inches long and 10 inches high. The top wall  36  and the bottom wall of each box  30  is perforated to allow the flow of ventilation gases  56  through the box  30 . 
     The boxes  30  are disposed in a plurality of tiers  40  within the cargo container  10  to form a cargo load  42  having a top side  44  and a bottom side  46 . The boxes  30  are disposed within the cargo container  10  such that the boxes  30  in the forward portion  24  of the enclosed space  22  are tightly packed proximate to the side walls  12  and to the forward wall  14 . 
     In a typical embodiment, such as illustrated in FIG. 1, the boxes  30  are disposed on individual pallet boards  48 . In one embodiment, the cargo container  10  is about 7½ feet in width and each pallet board  48  is typically about 48 inches in length and about 41 inches in width. Such dimensions allow the pallet boards  48  to be tightly packed within the cargo container  10  with little or no space between the cargo load  42  and the side walls  12  of the cargo van  10 , at least in the forward portion  24  of the cargo van  10 . Such a configuration is illustrated in FIG.  1 . 
     In the configuration illustrated in FIG. 1, the pallet boards  48  are placed side by side between the two side walls  12  of the cargo container  10 , one pallet board  48  having its long side disposed in parallel with the side walls  12  of the cargo container  10  and the other pallet board  48  having its long side disposed perpendicular to the side walls  12  of the cargo container  10 . Thus, as can be seen in FIG. 1, the cargo load  42  comprises a plurality of pallet board load combinations  50 , each pallet board load combination  50  consisting of the four pallet board loads  52  disposed on four individual pallet boards  48  arranged in close proximity to one another. When so disposed, the four pallet board loads  52  in each pallet board load combination  50  define a central vertical channel  54  at the intersection of the four pallet board loads  50  which extend from the bottom side  46  of the cargo load  42  to the top side  44  of the cargo load  42 . In a typical embodiment, each central vertical channel  54  has a cross-section which is approximately  6  inches by  6  inches. 
     As illustrated in FIG. 2, ventilation gases  56  can be flowed through the cargo load  42  from a blower (not shown) disposed within a bulkhead  58  located at the forward-most portion of the container van  10 . The bulkhead  58  has one or more ventilation outlet openings (not shown) disposed along a bottom wall  60  of the bulkhead  58 . The bulkhead  58  also has one or more inlet openings (not shown) disposed along a top wall  62  of the bulkhead  58 . A block of thermoplastic foam  63  is typically disposed at the rearward end  16  of the cargo van  10  to prevent the flow of ventilation gases  56  up around the rear-most end of the cargo load  42 . Instead of a block of foam, a sheet baffle can be used. In operation, the blower directs ventilation gases  56  from the bulkhead  58  via the outlet openings and into the ventilation channel  28  beneath the perforated floor  20 . At the same time, the blower draws a vacuum along the top of the cargo load  42 . As the ventilation gases  56  flow through the ventilation channel  28 , gases  56  are drawn upward through the perforated floor  20  into the cargo load  42 . The gases  56  are further drawn upward through the perforations in the boxes  30 , thereby ventilating the cargo within the boxes  30 . Above the cargo load  42 , the ventilation gases  56  are drawn into the bulkhead  58  through the inlet openings in the bulkhead  58 . 
     As can be seen in FIG. 2, a significant portion of the ventilation gases  56  pass through the vertical channels  54  rather than through the boxes  30 . In fact, so much of the ventilation gases  56  pass through the vertical channels  54 , that the amount of ventilation gases  56  traveling to the rearward portion  26  of the cargo container  10  is significantly diminished. As illustrated in FIG. 2, the amount of ventilation gases  56  available to ventilate the cargo in the rearward portion  26  of the cargo container  10  can be negligible. The method of the invention is directed to this problem. 
     In the method of the invention, as illustrated in FIGS. 3-13, a baffle sheet  64  is disposed across each of the vertical channels  54  within the cargo load  42 . The baffle sheets  64  are typically, but not necessarily, thin, flat structures and can be made from a variety of inexpensive materials, such as paper, cardboard, plastic and sheet metal. 
     At least some of the baffle sheets  64  comprise one or more baffle sheet openings  46  to allow the passage of gases through the baffle sheet  64 . In a typical embodiment, the baffle sheet openings  66  are circular and have a diameter between about ¼ inch and about 1 inch. FIGS. 7A,  7 B and  7 C illustrate three different baffle sheets  64 , having differing numbers of baffle sheet openings  66 . FIG. 7D illustrates a baffle sheet  64  having perforated cut-outs  68  which allow the user to open differing numbers of baffle sheet openings  66  in the baffle sheet  64 , as desired. FIG. 7E illustrates a baffle sheet  64  wherein some or all of the baffle sheet openings  66  are covered with a tape or similar covering  70  which can be peeled back. Such peel-back portions  72  can be used to wholly expose a baffle sheet opening  66  or partially expose a baffle sheet opening  66 . FIG. 7F illustrates a baffle sheet  64  which is a block of thermoplastic foam having removable foam cylinders to expose baffle sheet openings  66 . This embodiment of the baffle sheet  64  can be conveniently wedged into a vertical channel  54  when the pallet board loads  52  are assembled into a pallet board load combination  50 . The wedging of this embodiment of a baffle sheet  64  can be conveniently accomplished at any level within the ventilation channel  54 , usually without use of adhesives or other kinds of fastening means. FIG. 7G illustrates a baffle sheet  64  which is a long strip of material having baffle sheet openings  66  disposed therein. The baffle sheet openings  66  can be cut-outs  68  similar to the embodiment illustrated in FIG.  7 D. The baffle sheet openings  66  can also be covered with a covering  70  similar to the embodiment illustrated in FIG.  7 E. The baffle sheet  64  illustrated in FIG. 7G is just wide enough to cover the vertical channels  54  within an alternative container loading configuration illustrated in FIG. 8, discussed below. 
     Where the cargo load  42  is comprised of individual pallet board loads  52  as illustrated in FIG. 3, the baffle sheets  64  are typically disposed on the top side  44  of the cargo load  42  as illustrated in FIGS. 5 and 6. The baffle sheets  64  can be physically attached to the top side  44  of the cargo load  42  by adhesives, tapes or other suitable means. 
     FIG. 5 illustrates a typical configuration wherein the baffle sheet  64  most proximate to the forward end of the cargo container  10  has no openings  66 , thereby wholly closing the forward-most vertical channel  54  within the cargo load  42 . The second vertical channel  54  is covered with a baffle sheet  64  with three openings  66 . The third and fourth vertical channels  54  are covered with baffle sheets  64  having six openings  66  and the baffle sheet  64  disposed at the rearward-most portion of the cargo van  10  is covered with a baffle sheet  64  having  12  openings  66 . In this typical example, the baffle sheets  64  are used to provide for a predetermined pressure gradient above the cargo load  42  when ventilation gases  56  are circulated through the cargo load  42  from the bottom of the cargo load  42  to the top of the cargo load  42 . Typically, the predetermined pressure gradient is one in which equal quantities of ventilation gases  56  are drawn upwards through each portion of the cargo load  42 . 
     As illustrated in FIG. 3, one or more fans  73  disposed within a removable fan housing  75  can be slipped onto the top of the cargo load  42  via the rearward end  16  of the container van  10  to provide additional circulating power for ventilation gases  56  flowing within the rearward portion  26  of the enclosed space  22 . 
     FIG. 8 illustrates an alternative container loading configuration to which the method of the invention can be applied. In this configuration, specially constructed boxes  30 ′ are stacked one on top of another (without use of pallet boards  48 ) within the cargo van  10 . Each box  30 ′ has the configuration illustrated in FIG. 9 with four biased corners  76 . Each box  30 ′ has corner vents  77  disposed at each of the four biased corners  76 . When the boxes  30 ′ are stacked as illustrated in FIG. 8, vertical channels  54  within the cargo load  42  are provided at the intersection of the four individual boxes  30 ′ in each tier  40  within the load  42 . The comer vents  77  within each of the boxes  30 ′ allow ventilation gases  56  to enter the boxes  30 ′ directly from the vertical channels  54 . The corner vents  77  thus provide important additional ventilation passageways into each box  30 ′. 
     In the embodiment illustrated in FIG. 8, the baffle sheets  64  are of the type illustrated in FIG.  7 G. In the embodiment illustrated in FIG. 8, the baffle sheets  64  can be conveniently disposed between the top side  44  and the bottom side  46  of the cargo load  42  as illustrated in FIG.  10 . In this disposition of the baffle sheets  64 , the baffle sheets  64  are secured within the cargo load  42  merely by the weight of boxes  30  situated above the baffle sheet  64 . Thus, no adhesives, tapes or other attachment methods are required to secure the baffle sheets  64  in place. 
     FIG. 11 illustrates an alternative pallet board combination  50  useable in the invention. In the pallet board combination  50  illustrated in FIG. 11, boxes  30 ′ are disposed on individual pallet boards  48  as illustrated in FIGS. 11 and 12. A large baffle  78 , such as illustrated in FIG. 13, is disposed within each pallet board load  52  forcing ventilation gases  56  to percolate upwards through each of the six boxes  30 ′ in each tier  40  of each pallet board load  52  by closing off each of the vertical channels  54  formed by the biased corners  76  of the boxes  30 ′. Also, the large baffle  78  may include an extension flap  80  which can be used to drag several tiers of boxes  30 ′ out through the rearward end  16  of the cargo van  10 . As illustrated in FIG. 11, a baffle sheet  64  is disposed across the vertical channel  54  formed by the intersection of the four pallet board loads  52 . 
     By the embodiment illustrated in FIGS. 11-13, ventilation gases  56  are forced to be drawn upwards through the boxes  30 ′ by gas flow traveling vertically through openings disposed in the bottom walls of the boxes  30 ′. Ventilation gases  56  are also drawn laterally into each of the boxes  30 ′ from gases flowing within the several vertical channels  54  via the corner vents  77  in the biased corners  76  of each box  30 ′. 
     The invention is conveniently used for a wide variety of ventilating schemes. The method is useable wherein the ventilation gases  56  comprise ambient air, refrigerated air, a ripening agent and/or a preserving agent. having thus described the invention, it should be apparent that numerous structural modifications and adaptations may be resorted to without departing from the scope and meaning of the invention as set forth above and as described hereinbelow by the claims.