Abstract:
A transfer terminal includes a storage structure bounding a chamber, the chamber being adapted to receive bulk material. A surge bin is at least partially disposed within the chamber of the storage structure. The surge bin receives the bulk material for dispensing. In one embodiment, for a portion of the bulk material that cannot freely flow into the surge bin, mechanical structures are provided for transferring the bulk material into the surge bin. A passageway extends through or below at least a portion of the storage structure. The first surge bin is in communication with the passageway for delivering the bulk material thereto.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]    This application claims priority to U.S. Provisional Patent Application Serial No. 60/407,816, filed Sep. 3, 2002, which is incorporated herein by specific reference. 
     
    
     
       BACKGROUND OF THE INVENTION  
         [0002]    1. The Field of the Invention  
           [0003]    The present invention relates to storage structures. More particularly, the present invention relates to storage structures configured to store bulk materials and systems and methods for dispensing the bulk materials therefrom.  
           [0004]    2. The Relevant Technology  
           [0005]    Dome shaped storage facilities have been used for many years to store bulk materials prior to transport for end use. Bulk materials generally include grains, legumes, salt, cement, and other granulated or powdered flowable materials. For practical reasons, domed storage facilities are typically built at ground level (as opposed to being elevated). As a result, a majority of bulk material is located at or close to ground level.  
           [0006]    Conventional domed storage facilities operate by feeding the bulk material into the storage facility through an opening formed at the top. An outlet is centrally formed on the floor of the storage facility. When the storage facility is full, the bulk material flows out the opening under the force of gravity. As the storage facility empties, augers or other conventional conveyors within the storage facility are used to drag the bulk material from around the sides to the central opening.  
           [0007]    The bulk material is typically dispensed into a transport vehicle, such as a truck or train, by use of an external transfer facility. That is, a conveyor belt is disposed below the opening of the storage facility so as to carry the bulk material away from the storage facility. Outside of the storage facility, the conveyor belt slopes upwardly so as to feed the bulk material into an elevated hopper of the transfer facility. The transport vehicle then pulls up either next to or below the hopper. The hopper is then selectively opened so that the bulk material dispenses out under gravitational force into the transport vehicle.  
           [0008]    The above conventional process for dispensing bulk materials from dome shaped storage facilities has several shortcomings. For example, the use of the conveyor equipment to transport the bulk material from the storage facility to the external hopper adds increased expense and maintenance. For example, there is not only the cost of the conveyor equipment but also the cost for related foundations and support structures. In addition, each separate transport point requires the presence of a dust collection system and related maintenance.  
           [0009]    Furthermore, some bulk material storage facilities are not energy efficient in that they require all of the bulk material to be elevated twice: once to get the bulk material into the storage facility and once to get the bulk material from the storage facility to the transfer facility. As a result, such systems are not energy efficient.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]    Various embodiments of the present invention will now be discussed with reference to the appended drawings. It is appreciated that these drawings depict only typical embodiments of the invention and are therefore not to be considered limiting of its scope.  
         [0011]    [0011]FIG. 1 illustrates a front cross-sectional view of one embodiment of a storage structure of the present invention;  
         [0012]    [0012]FIG. 2 illustrates a side cross-sectional view of the embodiment of FIG. 1;  
         [0013]    [0013]FIG. 3 illustrates a top cross-sectional view of the embodiment of FIG. 1;  
         [0014]    [0014]FIG. 4 illustrates a side cross-sectional view of another embodiment of a storage structure of the present invention;  
         [0015]    [0015]FIG. 5 illustrates a top cross-sectional view of the embodiment of FIG. 4;  
         [0016]    [0016]FIG. 6 illustrates a front cross-sectional view of another embodiment of a storage structure of the present invention;  
         [0017]    [0017]FIG. 7 illustrates a front cross-sectional view of yet another embodiment of a storage structure of the present invention;  
         [0018]    [0018]FIG. 8 illustrates a side cross-sectional view of the embodiment of FIG. 7;  
         [0019]    [0019]FIG. 9 illustrates a top cross-sectional view of the embodiment of FIG. 7; and  
         [0020]    [0020]FIG. 10 illustrates a front cross-sectional view of another embodiment of storage structure of the present invention.  
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0021]    One embodiment of the present invention relates to storage structures having a passageway formed therethrough or thereunder for allowing a transport vehicle to be positioned directly under the storage structure. In this configuration, the potential energy of the bulk material elevated within the storage structure is used to directly dispense the bulk material from the storage structure into the transport vehicle. As such, the system is more energy efficient. In addition, the system is more economical in that it no longer requires the extensive conveyor system and related support systems.  
         [0022]    Depicted in FIGS. 1 and 2 is one embodiment of a transfer terminal  10  incorporating features of the present invention. Transfer terminal  10  comprises a storage structure  12  and a passageway  14 , in the form of a tunnel, transversely extending through storage structure  12 . In the embodiment of FIG. 1, storage structure  12  comprises a dome structure having a floor  16  and a singular dome-shaped boundary wall  18 . One method for constructing storage structure  12  is described in U.S. Pat. No. 4,324,074 which is incorporated herein by specific reference. It is appreciated that dome-shaped storage structure  12  shown in FIG. 1 is exemplary of the types of storage structures that may be employed in the present invention and that the storage structures are not limited to a dome-shaped structure. Other alternative shapes for storage structures contemplated by the present invention are square, rectangular, cylindrical, and the like. Although the storage structure can be any size, by way of example the chamber of storage structure  12  can have a volume greater than 1,000 cubic meters, greater than 50,000 cubic meters, or greater than 100,000 cubic meters.  
         [0023]    Boundary wall  18  and floor  16  bound an chamber  17  configured to store bulk material. As used in the specification and appended claims, the term “bulk material” is intended to include grains, legumes, salt, cement, sand, rock aggregate, fly ash, fertilizer, and other granulated or powdered flowable food and non-food materials. An aperture  21  centrally extends through the top of boundary wall  18  so as to communicate with chamber  17 . A fill line  19  extends through aperture  21 . Fill line  19  is connected to a bucket elevator or other conveyor system in order to fill chamber  17  with the bulk material. A dust collector  62  may be provided on a top portion of boundary wall  18  to collect dust from the bulk material as it is fed into chamber  17 . Other conventional forms of feeding bulk material into chamber  17  can also be used.  
         [0024]    Passageway  14  is bounded by a tunnel wall  15  that extends through chamber  17 . A dispensing aperture  26  centrally extends through the top of tunnel wall  15  so as to communicate with passageway  14 . A substantially cylindrical wall  28  upwardly extends from tunnel wall  15  so as to encircle aperture  26 . Wall  28  bounds a compartment  23 . Disposed within compartment  23  and connected to wall  28  is a hopper assembly  30 . Hopper assembly  30  comprises a surge bin  32 , a flow control valve  33 , a dust collector  34 , and a loading spout  36 . Surge bin  32  is secured to wall  28  such that bulk material is not able to leak between surge bin  32  and wall  28 . Surge bin  32  and wall  28  can be made of concrete, steel, and/or any other materials having the desired strength and wear properties.  
         [0025]    As shown in FIG. 1, the bulk material stored within storage structure  12  above hopper assembly  30  freely flows under gravitational force into surge bin  32 . The size and type of hopper assembly  30  depends upon the type and size of bulk material stored in storage structure  12 . In one embodiment of the invention, hopper assembly  30  dispenses bulk material at a rate of 100-400 tons per hour. Although surge bin  32  can be any desired size, in one embodiment surge bin  32  has a volume greater than 5 cubic meters, greater than 40 cubic meters, or greater than 90 cubic meters. It will be appreciated that wall  28  is exemplary of a structure for securing hopper assembly  30  above dispensing aperture  26  and that other structures may be employed for performing the same function.  
         [0026]    As depicted in FIGS. 1 and 2, passageway  14  is configured such that a large transport vehicle  22  (FIG. 2) can drive therethrough. The transport vehicle can be any form of truck, rail cart, or other type if vehicle. As such, passageway  14  has a height with sufficient clearance for transport vehicle  22 . As shown in FIG. 1, passageway  14  is formed on ground  20  and extends above floor  16  of storage structure  12 . As passageway  14  extends the entire width of storage structure  12 , transport vehicle  22  can thus drive straight through passageway  14 , be loaded with bulk material through hopper assembly  30 , and exit the other side of storage structure  12 . As also shown in FIG. 1, the width of passageway  14  is formed with sufficient clearance for transport vehicle  22 . In alternative embodiments, passageway  14  can be significantly wider to allow two or more transport vehicles to pass through side-by-side.  
         [0027]    Dispensing aperture  26  is formed over passageway  14  so that transport vehicle  22  can be moved directly underneath dispensing aperture  26 . Preferably, dispensing aperture  26  is positioned substantially centrally within storage structure  12  to promote the most efficient discharge of the bulk material from storage structure  12 . However, it will be appreciated that dispensing aperture  26  may be positioned anywhere along passageway  14  so that the bulk materials may dispense directly into transport vehicle  22 . Loading spout  36  is disposed in dispensing aperture  26  such that it is positioned to load the bulk materials directly into transport vehicle  22 .  
         [0028]    In one embodiment truck and/or rail weights or scales  24  are disposed within passageway  14  which assist in loading transport vehicle  22  with the bulk material. The weights or scales  24  are preferably positioned directly below hopper assembly  30  so that the weight of the bulk material is measured as transport vehicle  22  is being loaded.  
         [0029]    As discussed above, when dispensing the bulk material, hopper assembly  30  is disposed directly over passageway  14  such that any bulk material above hopper assembly  30  will gravitate into surge bin  32 . Because hopper assembly  30  is positioned well above floor  16  of storage structure  12 , additional mechanical means are required to fully empty storage structure  12 . Accordingly, in one embodiment of the present invention, as the bulk material becomes lower than hopper assembly  30  means are provided for transferring the bulk material from within chamber  17  but outside of surge bin  32  to within surge bin  32 . By way of example and not by limitation, depicted in FIG. 1 is one embodiment of a recirculating system  38  that may be appropriate for fine powders. The type of recirculating system appropriate for each system will depend largely on the bulk material being stored.  
         [0030]    Recirculating system  38  comprises a pneumatic transfer pod  40  positioned on each side of hopper assembly  30 . Transfer pods  40  are disposed below floor  16  of storage structure  12 . Recirculating apertures  42  are formed in floor  16  to convey bulk material from the bottom of storage structure  12  to transfer pods  40 . Transfer pods  40  then fluidize the bulk material and convey it through transfer lines  44  to the top of hopper assembly  30 . As such, substantially all of the bulk material below hopper assembly  30  may be dispensed out through hopper assembly  30 . In this embodiment, floor  16  of storage structure  12  may be somewhat sloped to assist the bulk material in flowing toward transfer pods  40 .  
         [0031]    Referring to FIG. 3, where recirculating system  38  is implemented with hopper assembly  30 , storage structure  12  is configured to accommodate the machinery and other equipment. Specifically, passageway  14  is formed substantially centrally within storage structure  12 . Hopper assembly  30  is formed directly over passageway  14 . Transfer pods  40  are placed on each side of hopper assembly  30 . Each transfer pod  40  is responsible for emptying that particular half of storage structure  12  as shown by the direction of the arrows. Work spaces may be provided in storage structure  12  to accommodate the mechanical system for hopper assembly  30  and/or recirculating system  38 . For example, an electric room  46  and a pod rooms  64  are constructed on the sides of passageway  14  so that the mechanics of hopper assembly  30  and recirculating system  38  may be easily accessed. In addition other work space, such as office space  50  may be constructed in storage structure  12 .  
         [0032]    It will be appreciated that additional structural features may be provided with the transfer terminals of the present invention. Such structural features may include ramps, floorings, stairs, and the like to access different parts of hopper assembly  30  or recirculating system  38 .  
         [0033]    [0033]FIG. 4 depicts an embodiment of a transfer terminal  100  similar to the embodiment of FIG. 1. In each of the following embodiments, like elements are referred to with like reference numbers. As shown in FIG. 4, multiple hopper assemblies  30  are positioned above corresponding multiple dispensing apertures  26 . In FIG. 4, passageway  14  is configured to receive two transport vehicles  22  to provide for more efficient loading of bulk material. The placement of hopper assemblies  30  depends on the particular design considerations for transfer terminal  100 . However, FIG. 4 serves to illustrate that multiple hopper assemblies  30  may be employed.  
         [0034]    [0034]FIG. 5 depicts the workspaces that may be constructed where two hopper assemblies  30  are used in conjunction with recirculating system  38  of FIG. 1. Recirculating system  38  comprises two transfer pods  40  positioned centrally in storage structure  12  on either side of passageway  14 . Transfer pods  40  operate in substantially the same fashion as in the embodiment of FIG. 1, however, transfer lines  44  are positioned such that each transfer line flows into a different hopper assembly  30 . As such, each transport vehicle  22  is loaded with bulk material located below hopper assemblies  30 . FIG. 5 also shows workspaces constructed for each hopper such as an electric room  40 , compressor room  48 , pod rooms  64 , terminal office  50  and storage room  66 .  
         [0035]    It is appreciated that passageway  14  may be constructed in a variety of ways. Turning now to FIG. 6, a transfer terminal  200  is shown having an alternative embodiment for passageway  14 . As illustrated in FIG. 6, floor  16  of storage structure  12  is constructed substantially flush with ground  20 . Passageway  14  is formed having a tunnel-like construction underneath storage structure  12 . As discussed above, passageway  14  is formed to allow sufficient clearance for a large transport vehicle  22 .  
         [0036]    In another embodiment of passageway  14 , not shown, dome shaped storage structure  12  may be elevated above ground  20  by pillars or some other foundation. In this embodiment, passageway  14  may not have a tunnel configuration but simply be the space underneath dome shaped storage structure  12 .  
         [0037]    In some embodiments, passageway  14  may extend only partially through storage structure  12 , although this embodiment is less preferred because it requires the transport vehicle  22  to back out of storage structure  12 . The width of passageway  14  may vary from extending the entire width of storage structure  12  to sufficient width to allow clearance for transport vehicle  22 .  
         [0038]    Recirculating system  38  may comprise various structures depending on the type of bulk material being stored in storage structure  12 . Referring now to FIGS.  7 - 9 , a transfer terminal  300  is depicted, wherein recirculating system  38  comprises a bucket elevator  52 . In the embodiment of FIGS.  7 - 9 , bucket elevator  52  is placed inside storage structure  12 . Bucket elevator  52  has an outlet line  54  placed in communication with surge bin  32  of hopper assembly  30 . It is appreciated that when a bucket elevator is used, additional space will need to be constructed or excavated under storage structure  12 .  
         [0039]    A series of recirculating apertures  42  are formed on floor  16  of storage structure  12 . The recirculating apertures  42  are disposed above a conveyor  56  which in turn is placed underneath floor  16  of storage structure  12 . Conveyor  56  extends from wall  18  of storage structure  12  to the bottom of bucket elevator  52 . As such, the bulk material is efficiently conveyed through recirculating apertures  42  onto conveyor  56 . Conveyor  56  then moves the bulk material to bucket elevator  52  which in turn dispenses the bulk material to hopper assembly  30  to be loaded in transport vehicle  22 . As shown in FIG. 9, a pair of conveyors  56  may be positioned on each side of storage structure  12 , each conveying material to bucket elevator  52 .  
         [0040]    When loading transport vehicles  22 , hopper assembly  30  feeds material naturally from the top of the dome until the level of bulk material falls to the upper portion of hopper assembly  30 . When the bulk material is located lower than hopper assembly  30 , conveyors  56  are used to draw bulk material down through the floor  16  of storage structure  12  and convey the bulk material to bucket elevator  52  which charges hopper assembly  30 . It is appreciated that bucket elevator  52  may be configured to initially fill storage structure  12  with bulk material. In another embodiment, not shown, bucket elevator  52  may be configured to be positioned externally of storage structure  12  so that additional excavation construction costs may be avoided.  
         [0041]    Referring now to FIG. 10, a transfer terminal  400  is shown having a recirculating system  38  in the form of a vertical auger  58 . Vertical auger  58  is positioned next to hopper assembly  30  and has an outlet spout  60  at the top thereof for dispensing bulk material into hopper assembly  30 . Vertical auger  58  may be appropriate for powder bulk materials, granulated materials and pellet materials. As also shown in FIG. 10, a dust collector  62  is placed on wall  28  of storage structure  12  to collect dust from the bulk materials.  
         [0042]    The transfer pods, bucket elevator, and vertical auger recirculation systems are exemplary of the types of structures and systems which are appropriate for means for transferring the bulk material from within chamber  17  but outside of surge bin  32  to within surge bin  32 . In other alternative embodiments within the scope of the present means, is appreciated that any number of other mechanical conveying systems can be used for transferring the bulk material to surge bin  32 . For example, compressed air/venturi systems, air-lift systems, combination mechanical screw and compressed air pumps, and other combinations or systems known to those skilled in the art can be used. It will be appreciated that the type of recirculation system will depend on the type of material stored in storage structure  12 .  
         [0043]    The present invention may be embodied in other specific forms without departing from its spirit or essential characteristics. The described embodiments are to be considered in all respects only as illustrative and not restrictive. The scope of the invention is, therefore, indicated by the appended claims rather than by the foregoing description. All changes which come within the meaning and range of equivalency of the claims are to be embraced within their scope.