Flexible Tank for a Shipping Container

Abstract

A flexible tank is used to transport liquids or semi-liquid material in a shipping container on a railroad car. It has an inner tank and at least one end closure with alternating interlaced hollow loops from two separate exterior layers. A nylon rope or similar securing element is passed through the hollow loops to use the exterior layers in an end closure to constrain the inner tank. An end flap may be welded to an exterior layer and positioned between the inner tank and the end closure. The hollow loops may be formed by folding over the exterior layers and cutting out complementary portions so the loops are in an alternating interlaced pattern. Capacity bands located around the periphery of the flexible tank suppress expansion of the flexible tank at their respective locations.

1 . A flexible tank for transporting bulk liquids or semi-liquid materials in a shipping container on a railroad car, comprising:
 an interior tank made of a flexible water-proof polymeric material, said interior tank being generally rectangular in shape with a width of at least one end of the interior tank being less than the length of the interior tank, the interior tank enclosing within it the bulk liquid or semi-liquid materials being transported;   a first exterior layer made of a flexible polymeric material in a generally rectangular shape, a first end of the first exterior layer having a series of hollow loops and spaces between the hollow loops in a widthwise direction along the first end, the hollow loops and spaces alternating in sequence;   a second exterior layer made of a flexible polymeric material in a shape and size substantially similar to the first exterior layer, a first end of the second exterior layer having a series of hollow loops and spaces between the hollow loops, the hollow loops and spaces alternating in sequence in the widthwise direction of the first exterior layer, the first end of the second exterior layer being matched up with the first end of the first exterior layer such that the hollow loops of the second exterior layer occur at the positions of the spaces of the first exterior layer and the spaces of the second exterior layer occur at the positions of the hollow loops of the first exterior layer;   a plurality of capacity bands located around the outer periphery of the second exterior layer, each one of said plurality of capacity bands constraining the expansion of the flexible tank at its location during movement of the railroad car; and   a rope, the rope passing through the alternating hollow loops of the first and second exterior layers and connecting the first and second exterior layers to each other, the interior tank being constrained within the first and second exterior layers connected by the rope.   
     
     
         2 . The flexible tank of  claim 1 , wherein the flexible tank is less than the length of the shipping container and is not supported by the end walls of the shipping container. 
     
     
         3 . The flexible tank of  claim 1 , wherein the flexible tank has a capacity of more than 8,000 liters. 
     
     
         4 . A method of transporting bulk liquids or semi-liquid materials in a flexible tank in a shipping container on a railroad car, comprising:
 folding over the ends of rectangular shaped first and second layers of flexible polymeric material to form a continuous loop over the entirety of the width of said ends of said first and second layers;   connecting the longitudinal sides of the first and second layers to form an open ended tube;   attaching a first end of a first end flap to the inside of one of the first and second layers near a first end of the open ended tube and a first end of a second end flap to the inside of one of the first and second layers near a second end of the open ended tube, the length of the first end flap being greater than the distance from its point of attachment to the first end of the open ended tube and the length of the second end flap being greater than the distance from its point of attachment to the second end of the open ended tube;   cutting portions from each one of the continuous loops of said ends of said first and second layers so as to become a sequence of alternating hollow loops and spaces, the hollow loops and spaces of the first layer interlacing with the hollow loops and spaces of the second layer;   inserting an inner liner into the interior space of the open ended tube formed by connecting the longitudinal sides of the first and second layers, the inner liner made of a flexible water-proof polymeric material so as to enclose within it the bulk liquid or semi-liquid materials being transported;   moving the respective second ends of the first and second end flaps to cover the ends of the inner liner;   closing the first and second ends of the flexible tank with the inner liner and end flaps constrained therein by threading a rope between the interlaced hollow loops of the first and second layers; and   placing a plurality of capacity bands at locations around the outer periphery of the flexible tank, each one of said plurality of capacity bands constraining the expansion of the flexible tank at its respective location during movement of the railroad car, the flexitank reliably not leaking during accelerations and decelerations of the railroad card.   
     
     
         5 . The flexible tank of  claim 4 , wherein the flexible tank is less than the length of the shipping container and is not supported by the end walls of the shipping container. 
     
     
         6 . The flexible tank of  claim 4 , wherein the flexible tank has a capacity of more than 8,000 liters.