Patent Application
20060180232
The present invention relates to transportation of flowable granular material in intermodal containers. More specifically, the present application discloses a method of using intermodal containers having hoppers for filling, storing, transporting, and dispensing granular materials therefrom with means for minimizing the segregation of the particles that comprise the granular material.
The present application relates to intermodal containers, which are bulk material containers that are mountable on standard shipping platforms such as on railroad cars, truck trailer beds, ships, and other modes of transportation. The containers are often used to ship bulk material, including granular material. The intermodal containers for bulk flowable granular materials often contain loading ports on the top and discharge ports on the bottom for loading and unloading cargo, i.e. granular material, within hoppers formed within the container. The present invention details a method for filling an intermodal container and transporting material while minimizing segregation of the granular material.
The present application is a method of handling bulk granular material. First, an intermodal container is filled with the granular material at a processing facility. The filling is done in such a manner as to minimize segregation of the granular material. The filled container is then stored until an order for the granular material is received from a customer. Upon receiving an order, the intermodal container containing the granular material is transported from the manufacturing facility to the customer. Once at the customer's location, the customer can dispense the granular material from the filled intermodal container, wherein the intermodal container has been designed to minimize segregation of granular material during the dispensing step.
The present invention is further explained with reference to the drawing figures, wherein like structures are referred to by like numbers throughout the several views. While the above-identified drawings set forth one embodiment of the present invention, other embodiments are also contemplated, as noted in the discussion. In all cases, this disclosure presents the present invention by way of representation and not limitation. It should be understood that numerous other modifications and embodiments can be devised by those skilled in the art which fall within the scope and spirit of the principles of this invention.
Intermodal container 10 is intended for use on a standard shipping platform, and thus is of a standard size. Preferably, the dimensions and other criteria for the container are those that are set forth in International Standard Organization (ISO) Section 55.180, specifically Standard 1496-4, a standard known in the art. The standard gives the dimensions for the exterior of the intermodal container 10. In the embodiment pictured, the intermodal container 10 is eight foot wide, by eight foot tall, by twenty foot long. Also included on the intermodal container 10, but not illustrated, are standardized features for nodes on each of the eight corners for stacking and lifting the container, and for interlocking it with adjacent containers. Additionally, lifting points are included as required by the standard, or for ease of use of the intermodal container 10.
Intermodal container 10 comprises two hoppers 22a and 22b, separated by a partition 24. Each hopper 22 has a loading port 26, an upper main storage area 28, a lower hopper portion 30, and one or more unloading ports 32. In addition, a portion of the container is unused storage space 34, below the lower hopper portion 30 of each hopper 22. Hoppers 22a and 22b are two distinct storage areas within the container 10. Hoppers 22a and 22b are separated by the partition 24. Partition 24 is an additional vertical wall constructed within the intermodal container 10, preferably situated to create a symmetrical division within the intermodal container 10 wherein each hopper 22 will represent approximately one half of the granular material storage space for the intermodal container 10. In the embodiment illustrated, partition 24 is a metal plate. In alternate embodiments, the intermodal container 10 may contain only a single hopper, or may contain more than two hoppers, so long as each hopper meets the design criteria for minimizing segregation.
Each loading port 26 is an opening through the top wall 16 of intermodal container 10. As illustrated in
In each hopper, just below loading port 26, is main granular material storage area 28. In the embodiment illustrated in
For each hopper, located adjacent and just below the main storage area 28 is the lower hopper portion 30. In the illustrated embodiment of
Each hopper portion 30 is designed to assure that substantially all material stored within the container flows out of the intermodal container 10 through the force of gravity. The hopper portions are connected to the walls 12, 13, 14, and 15, and the partition 24, or to the plates that comprise the main storage area 28 in an alternative embodiment. The hopper portions are also reinforced with angle irons or similar structures to support the granular material load being transported.
Unloading port 32 is an opening on the bottom wall 17 of the intermodal container 10.
In further describing the invention of the present application, the granular particulate materials are provided for reference as examples of bulk granular material: #11 and #14 grade roofing granules, and S-Grade color quartz ceramic coated crystals available from 3M Corporation, St. Paul, Minn. Such roofing granules contain a maximum of 0.3 percent moisture content, are opaque to protect an underlying asphalt substrate from the effects of sunlight, and are between a six and seven on the Moh's mineral scale. Such color quartz ceramic color crystals do not exceed 0.5 percent moisture content as determined by ASTM C566, and are on a hardness of between 6.5 and 7 on the Moh's mineral scale. All of these materials come in various colors including black, blue, brown, buff, green, gray, red, and white. Each of the particulate granules of the three mentioned products contain a mixture of sizes of particles determined by ASTM D451 as indicated in the following tables:
*Typical range
It is important that all of the above products have a homogenous mixture of the particle sizes when utilized for covering shingles or other applications. This homogenous mixture is necessary for maximum performance of the granules, which is a covering of asphalt shingles with a mix of particle sizes. The granules protect the asphalt of the underlying shingle to prevent degradation of the asphalt. This is accomplished by the granules preventing ultraviolet light from reaching the asphalt which quickly degrades the shingles. Further, the mixture is needed to assure a uniform weight and color when applied to the shingles for aesthetic purposes. As such, it is necessary to have a homogenous mixture of particles when applying the granules. To accomplish this, the following methods for preventing segregation of particles are used in connection with the use of the inventive intermodal container arrangement of the present invention.
Upon filling of the intermodal container 10, randomizing of the distribution of particulate size to create a homogenous load within the container is used. Typically, when piling particular matter of varying sizes within a mix, i.e., loading or unloading the material for storage, the mixture has a tendency to segregate. Larger granules have a greater potential energy than smaller granules. This greater potential energy transforms to greater kinetic energy as the granules free fall. When the granules reach the end of their fall, the greater kinetic energy of the larger particles causes them to deflect further from the objects the granules strike. This creates what is called a “piling effect”. Course granules are forced to the outer sides of a pile while the finer granules tend to stay in the middle. This piling effect occurs in storage piles, hoppers, silos, and wherever granules are allowed to fill a storage vessel in a free flowing manner. With the present invention, steps are taken to prevent this piling effect when loading and unloading the granules from the hopper(s) of the intermodal container 10.
The members 42, 44, and/or 45 are composed of hardened steel, scratch-resistant rubber, ceramic coated metal or polymers, or other similar high durometer materials to prevent wear. In this embodiment, the cross members extend between partition 24 and end walls 14 and 15 in one layer. Alternately, additional members 42, 44, and/or 45 extend between side walls 12 and 13 in a second layer, with alternating perpendicular members for additional layers. The cross members are located within main storage area 28 of the hopper so as not to interrupt flow upon discharge of the material from the intermodal container 10.
The intermodal container 10 of the present invention may also be designed to minimize segregation upon unloading of the particulate material therein. Specifically, the lower portion of the hopper should be designed to allow gravitational flow of substantially all material out of hopper 22. Also, because intermodal container 10 has been filled by a method of randomizing particle size and minimizing segregation, the material stored will be of a homogenous load prior to unloading. Preventing segregation upon unloading intermodal container 10 eliminates the need for remixing the bulk granular material being stored and transported.
When piling granular material, the material creates a pile that has a slope at an angle with the horizon. This slope is called the angle of repose. Small particulate matter, such as fine sand, has an angle of repose of about twenty-five degrees. More course material, such as some of the particulate matter contained in the roofing granules disclosed, has an angle of repose closer to forty degrees. When designing the hopper, in order to unload all the material within hopper 22, the sloped walls of the lower portion of the hopper should be designed with an angle that is greater than that of the angle of repose of the material, which in the case of the #11 roofing granules is thirty-eight degrees.
In designing hopper portions 30 of hoppers 22a and 22b (
The hopper 22 itself is constructed from hardened metal or is ceramic coated to maintain integrity and prevent abrasion while being filled. In one embodiment, the hopper 22 is lined with a polymeric material to promote flow of the granular material. Lower hopper portions 30 are designed depending upon the selected material which will be filled within hopper 22. A selected material may differ in color, size, or composition, or a combination of these or similar properties, and thus will have its own specific angle of repose. In this case, a hopper design of forty-five degrees will allow most particulate materials to discharge from the hopper 22 from gravitational flow.
In addition to hopper design, another way of minimizing segregation upon discharge is the use of a Binsert™ such as sold by Jenike & Johanson Inc., Billerica, Mass. As the material is discharged from hopper 22, material is free flowing which allows the material to segregate upon its shifting as it is discharged from the hopper. Material segregates by sifting, which occurs on the top surface of a pile of material as fine particles sift through the voids between larger particles as the hopper is emptied. Due to the emptying flow pattern within the hopper, fine material at the center will be withdrawn first followed by the courser material second, which creates a segregation of material. A Binsert™ is an insert near the discharge port which controls exit velocity to minimize the problem of sifting segregation. The use of a Binsert™ also allows a shallower hopper to be used, which increases the storage capacity and maximizes the efficiency of the inventive intermodal container 10.
In an alternative embodiment, if an unloading port is offset from the center of the bottom surface 17, it is preferable to have the loading port offset an equal distance in the opposite direction. Locating the ports on the same side will result in a larger angle going back to an asymmetrical side so course granules will be diverted down the side which will discharge first. Offsetting the ports will result in a more uniform angle of repose, thus keeping the mixture within the hopper more uniform as it is discharged from hopper 22.
The hopper(s) of intermodal container 10 may also be equipped with cleaning devices to help assure all material is discharged from the hopper 22 to prevent cross contamination if the hopper 22 is used for a different material such as one different in color, size, or composition. One method for cleaning is to provide a series of air nozzles strategically placed throughout the container, including above a randomization grid (i.e., grid 50), and at other critical areas that tend to impede flow such as weld seams within hopper 22. The air nozzles are connected to a series of pneumatic lines, which are then connected to compressed air. When hopper 22 contains a minimal amount of material to be discharged, compressed air is hooked up to the pneumatic line which then is blown through the strategically placed air nozzles to force all remaining granules to the base of the hopper 22. In another embodiment, hopper 22 can contain a shaker. A shaker is a mechanism which provides vibration at a certain harmonic to hopper 22. The resulting vibration of the hopper 22 acts to provide energy to bounce all remaining granules from critical areas such as seams or the randomization grid 50.
Additionally, to assure complete emptying of the hopper 22, moisture content is controlled within intermodal container 10. Absent venting, moisture content of the granules may vary and leave moisture on the surfaces of hopper 22. This prevents granules from leaving as granules will adhere to the moisture and create cross contamination if the hopper is later used for a different material. Also, moisture left behind can have a corrosive effect on the container. A solution for this is to create venting within the container. Systems of passive venting, such as gable vents, which are vents that contains a series of louvers to allow air to flow in and out of intermodal container 10, but prevents moisture from rain or other precipitation from entering the container, are provided on the intermodal container 10. For more active venting, a fan can be installed within the hopper 22 which will force air to flow through the granulated material and escape through the gable vent, or similar structure.
With the above design of an intermodal container, a method of handling bulk granular material that minimizes segregation of the granular material can be achieved. First, intermodal container 10 is filled with granular material at a granular material processing facility. While filling, segregation of the granular material is minimized by one or more of the arrangements described herein. The filled intermodal container can be stored until an order for the granular material is received from a customer. Alternatively, the container can be filled upon receiving an order from a customer. The container is then transported from the manufacturing facility to the customer upon receiving the customer order. The customer can store the filled intermodal container at its facility until the granular material is required for processing. Once the material is required for processing, intermodal container 10 can be moved to a dispensing station of a manufacturing process where the material is required. The granular material is discharged from the intermodal container at this dispensing station as described above. With the minimization of the segregation of the granular material during the filling and dispensing steps, it is not necessary for a manufacturer to have to remix the material that has been transported.
In the embodiment where the intermodal container contains a plurality of hoppers, each hopper may contain a selected material. The selected material in each hopper may be a different size, a different color, or different composition as that of an adjoining hopper. The customer can then dispense the granular material from the desired hopper of the intermodal container at its facility. For instance, a customer may request a shipment of number eleven red and number fourteen gray roofing granules. One hopper of the intermodal container will be filled with the number eleven red roofing granules while the other hopper will be filled with the number fourteen gray. The container is then stored until it is requested by the customer. Upon receiving a request by the customer, the container is transported via railroad, truck or ship. Once it reaches the customer's location, the container can store the granular materials in the intermodal container at the facility until the granular materials therein are required for use.
Once a customer has emptied an intermodal container, the customer can refill the container with raw material and transport the intermodal container back to its original processing facility. This improves efficiency of a system, by not shipping empty containers. Additionally, the containers may contain a GPS tag, which will allow the customer and/or supplier to know the whereabouts of a given container at any one time. GPS tags are known in the art.
Although the hopper is designed to discharge all material, such design leaves non-used storage area 34 in each intermodal container. Although this is not the most efficient way of shipping, that is, there is not a maximum use of the shipping space, it is still a savings of efficiency. The savings of efficiency comes from the lack of requirement of remixing a product that has been segregated due to transportation. The elimination of this remixing step makes up for the void of the non-used storage area 34 while shipping the container.
Although the present invention has been described with reference to preferred embodiments, workers skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention.
