Patent Application
20170144833
The embodiments herein relate generally to systems and methods for safely transporting liquid, and, more specifically, to systems and methods for safely transporting liquid using bladders designed to withstand the forces encountered in the shipping process.
Large quantities of liquid are typically transported in specialized containers. For example, tanker trucks are specially designed to handle liquid and utilize one or more large tanks that are towed by the truck. Specialized liquid-holding tanks are also used for transporting liquid via train or ships. In all cases, these specialized tanks have a variety of drawbacks.
Transporting liquid in traditional tanks can be costly and inefficient. For example, a tanker truck may have a single large tank that can only carry one type of liquid at a time. Large tanker trucks typically have capacities ranging from about 5,000 gallons to about 12,000 gallons. Because of their large size, using a tanker truck to transport smaller quantities of liquid is inefficient due to the wasted capacity. Moreover, after transporting the liquid to its destination, the tanker truck must be returned to a new location to obtain its next shipment of liquid. During this transition period, the truck is not useful for carrying any other type of cargo. These inefficiencies extend beyond trucks, similarly appearing in rail or ocean shipping situations.
In an attempt to overcome some of these deficiencies, some companies have attempted to design bladders to be filled with liquid and shipped. However, these bladders have universally failed due to their inability to withstand the shipping process. In particular, those bladders have failed the safety standards that test railroad shaking, railroad crashing, drop tests, and/or separate testing and certification from the rail and trucking agencies. These bladders are unsafe because they may burst during shipping.
Therefore, a need exists for systems and methods for shipping liquid in a safe and efficient manner. More specifically, a need exists for systems and methods for shipping liquids in smaller containers that fit within traditional shipping containers and can also withstand the forces inherent in the shipping process.
Embodiments described herein include systems and methods for safely transporting liquid. In one embodiment, a system includes multiple bladders, with each bladder having top and bottom surfaces, front and rear edges, opposing side edges, a valve located on the top surface proximate the front edge, and at least one seam located along at least one of the side edges. The system also includes a non-slip mat shaped to cover at least a portion of the floor of a shipping container. The bladders are shaped to fit within the shipping container such that at least a portion of the bottom surface of each bladder contacts the non-slip mat. The bladders are also shaped such that the side edges of each bladder can be aligned substantially parallel to the longitudinal axis of the shipping container.
The bladders may include a compression fitted flange at the front and/or rear edges of the bladder. The bladders can be sized such that, at full capacity, the side edges of the bladder contact the sidewalls of the shipping container. For example, a bladder may be sized to hold up to about 2500 gallons of liquid.
The outer material of the bladders may be made of polypropylene. The bladders may also include one or two inner layers of polyethylene film under a polypropylene cover. Similarly, the bladders may include a gas barrier layer for preventing gas from penetrating the bladder. The bladders may include strength bands woven into the outer material of the bladder. Those strength bands may be woven into the material in a direction that is substantially perpendicular to the seam along the side edge of the bladder.
The bladders are designed to work with any standard shipping containers, including 40-foot or 53-foot containers, refrigerated containers, and so on. An example footprint size of an inflated bladder is about 10 by about 12 feet.
In another embodiment, a method of transporting liquid is provided. The method includes covering at least a portion of a floor of a shipping container with a non-slip mat; placing a first bladder on the non-slip mat, the first bladder comprising a valve and at least one seam; arranging the first bladder such that the at least one seam is aligned with a sidewall of the shipping container; attaching a hose to the valve of the first bladder; and filling the first bladder with the liquid to be shipped.
The method may also include placing a second bladder on the non-slip mat, the second bladder comprising a valve and at least one seam; arranging the second bladder such that the at least one seam is aligned with a sidewall of the shipping container; attaching the hose to the valve of the second bladder; and filling the second bladder with the liquid to be shipped. Finally, the method can further include placing a third bladder on the non-slip mat, the third bladder comprising a valve and at least one seam; arranging the third bladder such that the at least one seam is aligned with a sidewall of the shipping container; attaching the hose to the valve of the third bladder; and filling the third bladder with the liquid to be shipped.
Both the foregoing general description and the following detailed description are exemplary and explanatory only and are not intended to restrict the scope of the invention as claimed.
The accompanying drawings, which are incorporated in and constitute a part of this disclosure, illustrate various embodiments and aspects of the present invention. In the drawings:
Reference will now be made in detail to the present exemplary embodiments, including examples illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.
Exemplary embodiments herein disclose systems and methods for safely transporting liquid. In one embodiment, the system comprises a plurality of bladders. The term “bladder” is used herein to mean any type of containment device that can be filled with fluid. Typically, a bladder is inflatable such that the dimensions and/or present volume of the bladder change as more fluid enters the bladder. However, the term is intended to be used in the least restrictive sense throughout this disclosure.
Bladders may be constructed in a variety of manners. One such manner of construction begins with one or more layers of materials that are cut to size and connected to one another. For example, a bladder may be formed from a single layer of thermoplastic polymer, such as polypropylene or polyethylene. Alternatively, a bladder may be formed from a multi-layer of material, with thermoplastic polymer material used for the outer and inner layers. In some embodiments a different thermoplastic polymer is used for the outer and inner layers. For example, in one embodiment polypropylene is used for the outer layer while polyethylene is used for the inner layer. Generally speaking, the bladders may be made from any type of material that provides adequate strength, contains liquids without spilling or seeping, and/or provides a gas barrier between the liquid and the external environment. There is no limit to the number of material layers that can be used to form the bladder; for example, in one embodiment two or more polyethylene inner layers are used under a polypropylene outer layer.
In one example embodiment, a bladder is manufactured by first producing a tubular sleeve comprised of one or more layers of materials. The tubular sleeve can be produced in a “seamless” manner, such that the tubular sleeve does not contain any seams along the length of the sleeve. That sleeve can then be cut to an appropriate size and closed on both ends with a seam on each end. As used herein, the term “seam” is intended to encompass a line along which two pieces of material are joined together. The material may be connected in any suitable manner. For example, sewing, stitching, welding (such as ultrasonic welding), melting, and other techniques may be used.
In one embodiment, a compression fitted flange is utilized to increase the strength of the seam. This type of seam involves wrapping at least one of the outer layers of materials back on itself such that the inner layers are encapsulated within the outer layers. The compression fitted flange may be secured by using high strength threading, for example. The tubular sleeve is typically closed on both ends with a similar type of seam on each end. The seam is known to be the weak point of the bladder. For example, during impact tests and drop tests, the seam is the most likely rupture point of a bladder.
An example bladder is illustrated in
In the embodiment of
Finally,
On the floor of the shipping container 200, a non-slip mat 210 is depicted. The non-slip mat 210 may be built into the shipping container 200 as a permanent fixture, or may be a removable mat that is placed in the shipping container 200 prior to placing the bladders 100 in the container. The non-slip mat 210 may be made from any material that provides adequate friction between the bladders 100 and the non-slip mat 210 without damaging the bladders 100. For example, the non-slip mat 210 may be carpet, rubber, or a textured polymer material.
The non-slip mat 210 may be placed down the longitudinal center of the floor of the shipping container 200. The non-slip mat 210 can have a width equal to, or less than, the width of the shipping container 200. The amount of friction between the non-slip mat 210 and each bladder 100 can influence the width of the non-slip mat 210 required to prevent the bladders 100 from moving during shipping. That is, a non-slip mat 210 with greater friction will require less width than a non-slip mat 210 with less friction. In practice, the safest option is to use a non-slip mat 210 that extends across the width of the floor of the shipping container 200.
In the embodiment of
By orienting the bladders 100 such that the seams 125 are substantially parallel with the longitudinal axis of the shipping container 200, the seams 125 are also substantially parallel with the sidewalls 240 of the shipping container 200. Typically, the sidewalls of shipping containers are not heavily reinforced as they are not expected to handle heavy loads. With that in mind, the bladders 100 may be sized such that the seams 125 do not make contact with the sidewalls 240 of the shipping container 200. In other embodiments, one or more of the seams 125 contact the sidewalls 240. However, based on the height of the bladders 100 relative to the height of the sidewalls, any contact between the seams 125 and the sidewalls 240 occurs below mid-height of the sidewalls. This avoids putting pressure on the weakest part of the sidewalls 240, instead putting pressure on an area further down the sidewalls 240. Furthermore, due to the geometry of bladders 100, the seams 125 do not put excessive pressure against the sidewalls 240 of the container. As a result, the bladders 100 can be used in containers with weak or unreinforced sidewalls, such as a refrigerated truck.
In some embodiments, orienting the bladders 100 such that the seams 125 are substantially parallel with the sidewalls of the shipping container 200 provides improved impact resistance. For example, if a shipping vehicle is involved in a head-on crash or sudden stop, the forces incident with the crash or stop cause the liquid in the bladders 100 to rush forward. For example, the liquid may be forced in a direction corresponding with the front of the truck or the rear edge of the bladders 100. In this example the rear edge of the bladders 100 experience an elevated pressure; however, the seams 125 experience a lower relative pressure due to their position along the side of the bladder 100, and are therefore able to resist rupturing.
The same holds true for an impact from the rear of the shipping vehicle. For example, if a truck is hit from behind by another vehicle, the force from that hit will cause the truck to move forward and the fluid in the bladders 100 to move toward the front edges 115 of the bladders facing the loading/unloading door 230 of the truck. In this scenario the front edges 115 of the bladders 100 experience an elevated pressure. Again, however, the seams 125 experience a lower relative pressure and are able to resist rupturing.
While
Bladders 100 may come in a variety of capacities based on their varying sizes. For example, bladders 100 may have a capacity of about 1000 gallons up to about 5000 gallons. Because the bladders 100 are not rigid, they may be filled with an amount of liquid that is not exactly equal to their intended capacity. That is, a 2000-gallon bladder 100 may have an operating capacity of, for example, 1800-2200 gallons. The upper limit is intended to prevent excessive pressure on the seams 125, while the lower limit may be set to establish a desired size and weight of the bladder 100 to minimize movement during shipping and maintain sufficient friction with the non-slip mat 210.
For example, some trucks have a total weight limit of around 80,000 pounds. Perhaps 65,000 pounds nay be dedicated to cargo weight. If the liquid to be shipped weighs approximately 8.35 pounds per gallon (similar to water), then the truck can transport about 7,800 gallons of water. In this scenario the shipper might choose to use three 2,600-gallon bladders 100, with each bladder filled to about 2600 gallons. On the other hand, if the liquid to be shipped is heavier per volume, such as molasses at about 12 pounds per gallon, then the truck could only handle about 5,400 gallons. In this example scenario, the shipper may choose to use two 2,500-gallon bladders filled to about 2,700-gallons each, or three 1,500-gallon bladders filled to about 1,800 gallons each. Additionally, different size bladders may be used in conjunction with one another. For example, one 2,500-gallon bladder and one 2,000-gallon bladder may be used simultaneously. Also, the bladders may be filled with different liquids and shipped together, since each bladder is self-contained and prevents any cross contamination.
A method of transporting liquid is also disclosed herein. An optional step of the method includes cleaning the floor of the shipping container and removing any sharp objects that may puncture a bladder. After this optional step, a non-slip mat may be laid down along the floor of the shipping container. The non-slip mat may be a carpet or a rubber mat, as discussed above. With the non-slip mat in place, the first bladder may be placed on top of the mat. Typically, the first bladder will be placed furthest away from the loading/unloading door of the shipping container. The bladder can be oriented such that at least one seam of the bladder is aligned parallel to a longitudinal axis of the shipping container. At this stage the bladder may be filled, or additional bladders may be loaded into the shipping container. For example, a user may attach a hose to the valve of the first bladder and fill it with liquid.
Either before or after filling the first bladder, the second bladder may be loaded into the shipping container in a similar orientation as the first, with the valve facing the loading/unloading door of the shipping container and at least one seam of the bladder aligned parallel to a longitudinal axis of the shipping container. The bladder can then be filled via a hose attached to the valve. This process can then be repeated for a third and/or fourth bladder, and can continue on for as many bladders as are available and needed in that situation.
Alternatively, the bladders can be filled outside the shipping container and then moved into the shipping container, for example via a forklift. This may be useful in situations where the bladders are being transported from one shipping container to another. For example, they may be transported from a rail container to a truck container. In that scenario a non-slip mat would be laid down in the truck container, and the filled bladders would be placed on that mat one by one via, for example, a forklift. Other methods of loading and unloading may be used as well, of course.
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.
