Abstract:
The present invention is directed to novel transportable silo systems for storage of materials. The invention relates to self-erecting silo storage systems for use in the oil and natural gas mining and drilling industries. The silo storage systems of embodiments of the instant invention are uniquely designed to improve storage capabilities and mobility while at the same time reducing space requirements at well sites.

Description:
[0001]    The instant application is a divisional of, and claims priority under 35 U.S.C. §120 to, U.S. patent application Ser. No. 13/658,551, filed Oct. 23, 2012, which claims priority under 35 U.S.C. §119(e) to U.S. Provisional Application 61/550,776, filed Oct. 24, 2011, and U.S. Provisional Application 61/661,044, filed Jun. 18, 2012, each of which are hereby incorporated by reference in their entireties. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The field of the invention relates to self-erecting silo storage systems for use in the oil and natural gas mining and drilling industries. The silo storage systems of embodiments of the instant invention are uniquely designed to improve storage capabilities and mobility while at the same time reducing space requirements at well sites. 
       BACKGROUND OF THE INVENTION 
       [0003]    Oil and natural gas drilling and well sites are often located in remote areas that may be difficult to access. Usable storage space at well and drilling sites is also frequently very limited due to the terrain at the well sites or other factors related to the inaccessibility of the sites. As a result, storage space for materials necessary for drilling and mining operations is often at a premium. Improving the efficiency and use of storage space at drilling and well sites can have important economic as well as practical benefits for drilling and mining operations. 
         [0004]    Mining companies sometimes make use of a technique termed “hydraulic fracturing” to aid in the extraction of fossil fuels from well sites. Hydraulic fracturing is the propagation of fractures in a rock layer caused by the presence of a pressurized fluid. Hydraulic fractures form naturally, as in the case of veins or dikes, and is one means by which gas and petroleum from source rocks may migrate to reservoir rocks. 
         [0005]    In some cases, oil and gas companies may attempt to accelerate this process in order to release petroleum, natural gas, coal seam gas, or other substances for extraction, where the technique is often called “fracking” or “hydrofracking.” This type of fracturing is done from a wellbore drilled into reservoir rock formations. The energy from the injection of a highly-pressurized fracking fluid creates new channels in the rock which can increase the extraction rates and ultimate recovery of fossil fuels. When done in already highly-permeable reservoirs such as sandstone-based wells, the technique is known as well stimulation. Operators typically try to maintain fracture width or slow its decline following treatment by introducing a proppant into the injected fluid. A proppant is a material, such as grains of sand, ceramic, or other particulates, that prevents the fractures from closing when the injection is stopped. Consideration of proppant strengths and prevention of proppant failure becomes more important at deeper depths where pressure and stresses on fractures are higher. 
         [0006]    A distinction can be made between low-volume hydraulic fracturing which is used to stimulate high-permeability reservoirs and high-volume hydraulic fracturing. Low volume fracking operations may consume 20,000 to 80,000 gallons of fluid per well. High-volume hydraulic fracturing, which is used in the completion of tight gas and shale gas wells can use as much as two to three million gallons of fluid per well. 
         [0007]    The large amount of water and proppant required in a fracking operation at a well site requires that these materials be stored close to the well site so that they may be used as needed. Typically, tractor trailer rigs are used to transport these materials to well sites. If no or insufficient storage space is available at the well site, it is oftentimes necessary to store the materials in the same tractor trailer rigs that delivered the materials to the well site. This is an inefficient and frequently cost-prohibitive solution to the storage problem because the trailers must be parked until needed. This is costly because the drivers and their trucks are forced to waste valuable time out of service. Thus, the efficient storage of materials at oil and natural gas well sites is a critical factor in the successful implementation of fracking operations—for practical and economic reasons. 
         [0008]    The storage systems in embodiments of the instant invention are a novel and non-obvious solution to the storage problems described above. 
       SUMMARY OF THE INVENTION 
       [0009]    The present invention is directed, in certain embodiments, to a storage system comprising: a trailer, the trailer including: a trailer bed; a flipper mechanism coupled to said trailer bed; a rocker arm coupled to said trailer bed and said flipper mechanism; a first hook plate and a second hook plate attached to said flipper mechanism, wherein said first hook plate and said second hook plate are laterally opposed to each other on said flipper mechanism and wherein said first hook plate and said second hook plate are oriented at a first non-zero angle with respect to each other; a storage bin, the storage bin including: a plurality of support legs; a first pin and a second pin attached to said plurality of support legs, said first pin coupleable to said first hook plate and said second pin coupleable to said second hook plate. 
         [0010]    In certain embodiments, the storage system further comprises a third hook plate and a fourth hook plate attached to said flipper mechanism, wherein said third hook plate and said fourth hook plate are laterally opposed to each other on said flipper mechanism and wherein said third hook plate and said fourth hook plate are oriented at a second non-zero angle with respect to each other; and a third pin and a fourth pin attached to said plurality of support legs, said third pin coupleable to said third hook plate and said fourth pin coupleable to said fourth hook plate. 
         [0011]    In certain embodiments, the storage system of the invention is such that said first non-zero angle and said second non-zero angle are equal to each other. 
         [0012]    In certain embodiments, said first pin and said second pin are oriented at a third non-zero angle with respect to each other. 
         [0013]    In certain embodiments, said third pin and said fourth pin are oriented at a fourth non-zero angle with respect to each other. 
         [0014]    In certain embodiments, said first pin and said second pin are oriented at approximately 90 degrees with respect to one another. 
         [0015]    In certain embodiments, said third pin and said fourth pin are oriented at approximately 90 degrees with respect to one another. 
         [0016]    In certain embodiments, said third non-zero angle and said fourth non-zero angle are equal to each other. 
         [0017]    In certain embodiments, said storage system further comprises a base platform. In certain embodiments, said base platform comprises tire guide rails. In certain embodiments, said base platform is configured to support three of said storage bins in a vertical position. In certain embodiments, said base platform is configured to support two of said storage bins in a vertical position. In certain embodiments, said base platform is configured to support one of said storage bins in a vertical position. 
         [0018]    In certain embodiments of the invention, said trailer comprises independently operable hydraulic support legs. In other embodiments, said trailer comprises non-hydraulic support legs. In certain embodiments of the invention, said non-hydraulic support legs are positioned at a middle section of said trailer. 
         [0019]    In certain embodiments of the invention, said flipper mechanism is rotatably coupled to said trailer. In certain embodiments of the invention, said flipper mechanism is coupled to the rear end of said trailer. 
         [0020]    In certain embodiments of the invention, said flipper mechanism further comprises one or more pneumatic locking pins couplable to said storage bin. In certain embodiments, said flipper mechanism further comprises one or more pneumatic locking pins couplable to said support legs. 
         [0021]    In certain preferred embodiments of the invention, said rocker arm is coupled to said flipper mechanism via a second arm. In certain embodiments, said rocker arm is coupled to an actuator. In certain embodiments, said actuator is a hydraulic cylinder or a hydraulic piston. 
         [0022]    In certain embodiments, said rocker arm is curvilinear such that it forms a non-zero angle. In certain embodiments, lines drawn from each end of the rocker arm down a center axis of the rocker arm intersect with each other at a middle section of said rocker arm. In certain preferred embodiments, said non-zero angle is greater than 90 degrees. In certain preferred embodiments, said actuator is coupled to a middle section of said rocker arm. 
         [0023]    In certain embodiments, said first and second hook plates do not comprise a latching mechanism. In certain embodiments, said third and fourth hook plates do not comprise a latching mechanism. 
         [0024]    In other embodiments, said first and second hook plates comprise a latching mechanism. In other embodiments, said third and fourth hook plates comprise a latching mechanism. 
         [0025]    In certain embodiments, the invention is directed to methods of raising a storage bin to a vertical position comprising: positioning a trailer onto the surface of a base platform; activating independent hydraulic jacks to elevate the rear end of said trailer; wherein said trailer includes: a flipper mechanism coupled to said trailer; a rocker arm coupled to said trailer and said flipper mechanism; a first hook plate and a second hook plate attached to said flipper mechanism, wherein said first hook plate and said second hook plate are laterally opposed to each other on said flipper mechanism and oriented at a non-zero angle with respect to each other; wherein said first hook plate and said second hook plate are coupled to pins attached to support legs on said storage bin; activating an actuator coupled to said rocker arm to raise said storage bin to a vertical position; releasing said hydraulic jacks to lower said rear end of said trailer to thereby disengage said storage bin from said hook plates and vertically position said storage bin on the surface of said base platform. 
         [0026]    In certain embodiments, the invention is directed to methods of lowering a storage bin to a horizontal position on a trailer comprising: positioning a trailer onto the surface of a base platform; activating independent hydraulic jacks to elevate the rear end of said trailer to engage pins attached to support legs of the storage bin; wherein said trailer includes: a flipper mechanism coupled to said trailer; a rocker arm coupled to said trailer and said flipper mechanism; a first hook plate and a second hook plate attached to said flipper mechanism, wherein said first and second hook plate are laterally opposed to each other on said flipper mechanism and oriented at a non-zero angle with respect to each other; activating an actuator coupled to said rocker arm to lower said storage bin to a horizontal position; releasing said hydraulic jacks to lower said rear end of said trailer. 
         [0027]    In certain embodiments, the invention is directed to a trailer comprising: a trailer bed; a flipper mechanism rotatably coupled to said trailer bed; a rocker arm coupled to said trailer bed and said flipper mechanism; a first hook plate and a second hook plate attached to said flipper mechanism, wherein said first hook plate and said second hook plate are laterally opposed to each other on said flipper mechanism and wherein said first hook plate and said second hook plate are oriented at a first non-zero angle with respect to each other; an actuator coupled to said rocker arm. 
         [0028]    In certain embodiments, the invention is directed to a trailer wherein said first hook plate and said second hook plate are respectively coupleable to a first pin and a second pin of a storage bin, wherein the first pin and the second pin are oriented at a non-zero angle with respect to each other. 
     
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         [0029]    Appended  FIGS. 1-16  depict certain non-limiting embodiments of the fracture sand silo system and related systems. The figures are not intended to limit the scope of the invention but, instead, are intended to provide depictions of specific embodiments, features and non-limiting characteristics of the systems described herein. More specifically, the Figures depict certain non-limiting embodiments of the invention as follows: 
           [0030]      FIG. 1  depicts a silo system in a horizontal orientation on a trailer bed located on a base platform. 
           [0031]      FIG. 2  depicts a silo system being raised from or lowered onto a trailer bed. 
           [0032]      FIG. 3  depicts a silo system in an upright vertical orientation. 
           [0033]      FIG. 4A  depicts a hook plate.  FIG. 4B  depicts a hook plate, pin and manual latching mechanism. 
           [0034]      FIG. 5  depicts a pin attached to a support leg. 
           [0035]      FIG. 6  depicts a flipper mechanism. 
           [0036]      FIG. 7  depicts a flipper mechanism in an upright orientation attached to a trailer bed. 
           [0037]      FIG. 8  depicts the base of a silo with four support legs and pins attached to the four support legs. 
           [0038]      FIG. 9  depicts the lower portion of a flipper mechanism with a pin engaged with a hook plate. 
           [0039]      FIG. 10  depicts a free-standing silo disengaged from a flipper mechanism and trailer bed. The flipper mechanism is fully retracted and in a horizontal orientation. 
           [0040]      FIG. 11  depicts an upright flipper mechanism on a trailer bed which is resting on a base platform. 
           [0041]      FIG. 12  depicts the unique interaction between the pins attached to the silo legs and the corresponding hook plates attached to or part of the flipper mechanism. The figure also depicts manual latching mechanisms engaged with pins. 
           [0042]      FIG. 13  depicts a manual latching mechanism engaged with a pin that is seated in a hook plate. 
           [0043]      FIG. 14  depicts a side view of three silos positioned in the vertical orientation on a base platform. 
           [0044]      FIG. 15  depicts a side view of two silos positioned side-by-side on two different base platforms. In between the two silos is a dual belt conveyor system. 
           [0045]      FIG. 16  depicts an arrangement of six silos, in the “six pack” configuration, positioned vertically on two separate base platforms. In between the two rows of three silos is a dual belt conveyor system. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0046]    The self-erecting silo systems of embodiments of the instant invention have many unique features and novel characteristics that distinguish them over prior systems. They also have many improved benefits over prior systems, some of these benefits are summarized below. As used in the present application “coupling” between two components, or when two components are “coupled,” means that the two components are linked together, which could include linkage via an intervening component or element. As used herein, components or elements that are discussed separately could be part of the same component or element. 
       Silos 
       [0047]    The silos of embodiments of the invention may be used to store any material, including, but not limited to water, sand, proppant or an acid solution. In certain embodiments, the silo  100 , may be used to store an approximately 16-40% acid solution, or an approximately 20-50% acid solution, or an approximately 25-45% acid solution, or an approximately 30-40% acid solution, or an approximately 35% acid solution. In certain embodiments, the acid may be hydrochloric acid (HCl). In certain preferred embodiments, silo  100  may be used to store an approximately 16-40% HCl solution, or an approximately 20-50% HCl solution, or an approximately 25-45% HCl solution, or an approximately 30-40% HCl solution, or an approximately 37-40% HCl solution, or an approximately 35% HCl solution. In certain embodiments, the silos of embodiments of the invention may be configured for or usable in fracking applications. 
         [0048]    The silos in certain embodiments may be coated on the inside with one or more salt-resistant coatings. In certain other embodiments, the silos may be coated on the inside with one or more acid-resistant coatings. 
         [0049]    In certain embodiments, the silos may contain one or more devices for monitoring the level of the contents. The monitoring devices may be sonic, radar, optical, inductive or mechanical level monitors. In certain embodiments, load cells or strain gauges attached to the silo legs may be used to weigh the contents of the silo. Measuring the contents is useful for inventory management, determining and controlling the rate of usage, and avoiding over filling or unexpected empty conditions. 
       Base Unit 
       [0050]    The base unit of the self-erecting silo system allows for a rigid stable base for installation, operation and removal of sand silos. The flat bottom unit, which may support one or more silos, allows larger weight-bearing area on the ground resulting in lower ground pressure per unit weight of system compared to comparable systems that do not include a flat bottom unit. The generator system allows self-contained operation of the entire system. The air boost system reduces the time required for sand silo filling. Within the air boost system, a blower with variable speed drive allows a constant pressure air delivery to multiple fill tubes. Fill tubes are tubes that are used to fill the silos of the invention with a proppant such as, for example, sand. In certain embodiments of the invention, from one to four fill tubes may be attached to a silo of the invention. A blower pipe incorporated into the base unit allows for quick connection to fill silo units with auxiliary port to charge a second base unit. A power distribution center is included for distribution of power to the one to three silos positioned on a base platform with preinstalled hardware to operate a second base platform. A control power transformer is included for integrated manual control system. The base may be transported as though it were a trailer by attaching it to a tractor. 
       Silo Trailer 
       [0051]    The silo trailer includes hydraulic jacks at the rear of trailer which allows for carrying out the following functionalities: (a) raising of the trailer to allow silo clearance during raising of the silo; (b) leveling and stabilizing the trailer on the base unit to allow raising and lowering of the silo from a stable platform; (c) the silo, once raised, is lowered onto the platform by lowering the hydraulic jacks; (d) continued lowering of the jacks disengages the trailer from the silo; and (e) once the trailer is positioned, the hydraulic jacks are engaged to raise the silo rear thereby engaging the silo for lowering and tow away. 
         [0052]    Erecting mechanism compound linkage. The erecting mechanism allows the use of single stage hydraulic cylinders (that contain one barrel and one piston) for ease of manufacture and maintenance. The erecting mechanism also allows for rotation of the silo during raising to pass through 90 degrees to allow for site variations. 
         [0053]    Silo attachment. Hook plates are perpendicular assuring proper silo alignment when the trailer is backed into position. Pneumatic latch pins (or the latching mechanism depicted in  FIGS. 4B ,  12  and  13 ) engage to hold the silo attachment pins in the silo hook plate for raising, lowering, and transportation. This is done from ground level, without auxiliary equipment. Trailer operation controls are performed remotely via wireless control panel with a hardwired pendant controller as a back-up. 
       Sand Silo 
       [0054]    Shuttle conveyor. Conveyors move material, such as sand or other solid or semi-solid material used in fracking applications, horizontally. This allows a lower overall installed height than using conventional inclined chutes. Variable frequency drives are installed to allow control of material feed rate. The shuttle conveyor is reversible to allow discharging material from either side of the silo. In certain embodiments, the shuttle conveyor may be controlled by an electric drive system that repositions the conveyor in any direction. The conveyors transport in position on the silo. The conveyor is mounted on rollers to allow multiple placement options. In certain embodiments, this allows the customer to reposition to feed a second conveyor if necessary. In certain embodiments, this also allows the conveyor to be repositioned to drain the silo independently. In still further embodiments, this also allows the conveyor to be removed and replaced quickly for purposes of maintenance and repair. In certain embodiments, multiple fill lines allow simultaneous loading from various locations. In a preferred embodiment, the shuttle conveyor is reversible to allow discharging of material to either side of the silo. The speed of the conveyor is remotely controlled via a digital electronic system, providing precise control of the discharge rate to match the required flow of the fracking operation. 
       System 
       [0055]    The self-erecting silo systems of embodiments of the instant invention are highly mobile, with a modularized construction. The self-erecting silo system allows for ground level installation, operation and disassembly without additional equipment such as lifts, cranes or ladders. The self-erecting silo system allows approximately three times the onsite usable sand storage within the same foot print as existing systems. The systems of embodiments of the instant invention are designed to operate in multiple configurations based on customer requirements. The systems embodiments of the instant invention also comprise manual control panels to operate the entire system from a single location. 
         [0056]    In certain embodiments of the invention, the dual belt conveyor and the shuttle conveyors both have Variable Frequency Drives (VFD). In certain embodiments, the end of the dual belt conveyor that drops proppant into a container, such as a hopper or a blender hopper, will have a device (such as, for example, a pulsed radar device) that will constantly monitor the level of sand (or other proppant) in the container, hopper or blender hopper. In certain embodiments, the pulsed radar device will communicate to the VFD&#39;s on the shuttle and dual belt conveyors in order to increase or slow their speeds so that the level of proppant in the container, hopper or blender hopper may be adjusted and controlled. This system can be wireless or Ethernet cable connected. In preferred embodiments, the systems of the invention are designed to maintain a constant level and supply of sand, or other proppant (which is adjustable) from the one or more silos to the container, hopper or blender hopper that feeds the fracking operation (“the frac job). In preferred embodiments of the invention, the system will also be able to monitor the level of sand in each silo. In certain preferred embodiments, this monitoring is accomplished using, for example, pulsed radar monitors positioned inside of the silos of the invention at the top portion of the silo. In certain preferred embodiments, a daylight visible LED sign on the base unit will display how much sand is in each silo. The pulsed radar on the top of the silo is used to detect the sand profile in the silo, as it takes the angle of repose of the sand into consideration and produces an effective level in the silo. In certain preferred embodiments, the systems of the invention are designed to determine the level of proppant in the silo in real time. In preferred embodiments, the system will detect the amount of proppant in the silo in units of mass, such as pounds or kilograms. In preferred embodiments, since the system is designed to monitor proppant amounts in real time, the system can furnish the rate at which the sand or other proppant is being removed from the silo, as well as the rate of sand delivery going into the blender hopper originating from the one or more silos. In order to maintain an efficient frac job, it is necessary to control the rate of sand or other proppant that is being pumped into the well. In certain embodiments, the rate at which proppant or other material is released from any of the silos of the invention is regulatable. In certain embodiments, said regulatable flow of material or proppant from each silo of the invention is controlled using detectors and automated. 
         [0057]    In certain preferred embodiments, the flow of proppant from the silos of the invention to the storage bin, container, hopper or blender hopper is automatically regulated and controlled by a pre-set program or a program determined by conditions at the frac job. 
         [0058]    Erection assembly. In one embodiment, the self-erecting silo system includes an erection assembly comprising a hydraulic jack and a rocker arm. In one embodiment the rocker arm has a distal end and a proximal end. In this embodiment, the proximal end is movably or rotatably attached to the trailer, while the distal end is attached or coupled to a flipper mechanism that is adapted to be docked to a silo. The hydraulic jack, which may also be attached or coupled to the trailer, may have an actuating arm that is attached or coupled to a middle section of the rocker arm that is located between the distal and proximal ends. Locating the attachment or coupling point of the actuating arm at the middle section of the rocker arm may beneficially allow the use of a hydraulic jack and/or actuating arm that is smaller than a hydraulic jack and/or actuating arm attached directly the flipper mechanism (or one that is of a standard size that is readily available). Further, such a configuration may lead to a smaller range of motion of the hydraulic jack in the tangential direction as the hydraulic jack is operated to move the actuating arm through its full range of motion (with the actuating arm attached or coupled to the rocker arm or the flipper mechanism). In an aspect of this embodiment, the distal end and the proximal end may be at a non-zero angle with respect to one another. In this aspect, the trailer section at which the proximal end is attached or coupled to the trailer may be formed to fully support a surface of the proximal end when the hydraulic jack is in an equilibrium position, such as when a silo has been placed in the fully erect position, or when a silo has been placed in the fully reclining position on the trailer. In this aspect, proper support of the rocker arm in the position of equilibria may lead to lower stresses upon the rocker arm and lead to a more resilient assembly. 
         [0059]    In a related embodiment, the self-erecting silo system may include a plurality of erection assemblies as described above. For example, in an aspect of this related embodiment, the self-erecting silo system may include two erection assemblies, for example, located on opposing sides of the trailer. 
         [0060]    Silo—flipper mechanism interface. The flipper mechanism in certain embodiments is the part of the self-erecting silo system that is configured to be attached or coupled to a silo or a hook plate that is attached to a silo. In one embodiment, the flipper mechanism includes hooks adopted for coupling to projecting pins of the silo or the hook plate of the silo. The openings of the hooks allow a trailer to be easily backed onto an erect silo, given the play allowed by the openings of the hooks. In this way, backing the trailer onto the erect silo may not need to be done with great precision, given that the pins of the silo or the hook plate of the silo (or, in another embodiment, the pins of the silo and the hook plates of the flipper mechanism) need not be threaded through one or more holes on the flipper mechanism in coupling the silo to the self-erecting silo system. 
         [0061]    In one aspect of this embodiment, the pins of the silo or hook plates of the silo may not all be parallel; for example, two or four of these pins may be oriented at a non-zero angle with respect to one another. In this aspect, correspondingly, the corresponding hooks of the flipper mechanism will also be oriented at a non-zero angle with respect to one another so that the two or four pins may operably couple to their corresponding hooks. Angling the pins with respect to one another (and, correspondingly, angling the hooks with respect to one another) may reduce or eliminate undesired lateral motion of the silo and/or the hook plate of the silo with respect to the self-erecting silo system when the silo is coupled to the self-erecting silo system. 
         [0062]    In a variation of the above embodiment, the projecting pins may be located on the flipper mechanism, whereas the corresponding hooks for receiving the pins may be located on the silo or on the hook plate of the silo. 
         [0063]    In the embodiment depicted in  FIG. 1 , the silo  100  may be mounted on a trailer  102  and transported using a truck  104  to a site where the silo is to be employed. Upon arrival at the site, the truck  104  may be used to position the trailer  102  onto the surface of a base platform  106  that has been prepositioned at the site. In a preferred embodiment, from one to three vertical free-standing silos may be positioned on a single base platform  106 . In another preferred embodiment, two vertical free standing silos may be positioned on a single base platform  106 . In another preferred embodiment, three vertical free standing silos may be positioned on a single base platform  106 . The base platform  106  serves to stabilize the silo  100  and the trailer  102  as the silo  100  is deployed to a vertical position. The base platform  106  also functions to provide stability to the silo  100  once it is in the vertical position. The base platform  106  additionally acts to enhance stability when the silo  100  is retracted back onto the trailer  102  after deployment. 
         [0064]      FIG. 2  depicts, in an embodiment, an actuator  202  (which in certain embodiments may be a hydraulic cylinder or rod) that is coupled to the trailer  102  and a rocker arm  204 . The rocker arm  204  is coupled to the trailer  102  at a pin  212  which serves as a pivot point for the rocker arm  204  about which the rocker arm  204  can rotate. The rocker arm  204  is also coupled to an arm  206 . Arm  206  is coupled to the flipper mechanism  210  which is in turn coupled to the silo  100 . The flipper mechanism  210  is also coupled to the trailer  102  at pin  208 . Pin  208  serves as a pivot point for the flipper mechanism  210  about which the flipper mechanism  210  can rotate. The silo  100  may be raised to a vertical position (or lowered to a horizontal position) by activating the actuator  202  such that the rocker arm  204  and arm  206  rotate the flipper mechanism  210  from a horizontal to a vertical position (or conversely from a vertical to a horizontal position.) The base platform  106  provides stability to the silo  100  as well as the trailer  102  during and after deployment or retraction of the silo  100 . 
         [0065]      FIG. 3  depicts the silo  100  in a fully vertical position but still coupled to the flipper mechanism  210  which is in turn coupled to arm  206  and the rocker arm  204 . 
         [0066]      FIG. 4A  depicts a hook plate  402  that is attached to or is part of the flipper mechanism  210  in an embodiment of the silo system. 
         [0067]      FIG. 4B  depicts a pin  1301  and a latching mechanism comprising a hinged plate  1304  with a hole which is so located such that the hole in the plate may receive the end of pin  1301 . In one embodiment, the latching mechanism comprises a spring  1312 , a hinge  1308 , a lever handle  1306  and a plate  1310  to secure the lever  1306 . 
         [0068]      FIG. 5  depicts, in an embodiment, a pin  502  that is attached to a silo leg  504  that may, in embodiments of the invention, be received by hook plate  402 . 
         [0069]      FIG. 6  depicts an embodiment of a flipper mechanism that includes hook plates  604 ,  606 ,  608  and  610  attached to or part of the flipper mechanism  602 . In this embodiment, each of these hook plates is configured to receive a corresponding pin attached to the legs of the silo. Reception of each pin that is part of or attached to the leg of the silo by a corresponding hook plate assists in securing a silo to the flipper mechanism, as is described in greater detail below. 
         [0070]      FIG. 7  depicts hook plates  702 ,  704 ,  706  and  708  on flipper mechanism  710  in an embodiment. In this embodiment, the flipper mechanism  710  is coupled to trailer  102  through a pin  208  which is not depicted in  FIG. 7  (but is depicted in  FIG. 2  as  208 ) and a corresponding pin on the other side of trailer  102  that is also not depicted in  FIG. 7 ); arms  714  and  716 ; rocker arms  718  and  720 ; and actuators  722  and  724 . Also depicted is hydraulic jack  726  and support feet  727 ,  728  and  729 . 
         [0071]    In the embodiment depicted in  FIG. 8 , pins  806  and  808  are attached to different faces of silo leg  802 . Similarly pins  810  and  812  are attached to different faces of silo leg  804 , so that pin  812  and pin  808  are substantially parallel to one another, while pin  806  and pin  810  are substantially parallel to one another. Moreover, each of pins  812  and  808  are oriented at a non-zero angle with respect to each of pin  806  and pin  810 . Pins  806  and  812  are laterally opposed to each other. Pins  808  and  810  are laterally opposed to each other. Angling the pins with respect to one another (and, correspondingly angling corresponding hook plates of the flipper mechanism with respect to one another as depicted in  FIG. 6 ) reduces or eliminates undesired lateral motion of the silo and/or the hook plates of the flipper mechanism with respect to the self-erecting silo system when the silo is coupled to the flipper mechanism. Further, this novel and non-obvious orientation of the four pins  806 ,  808 ,  810  and  812  allows for self-alignment of the pins with the corresponding hook plates attached to or part of the flipper mechanism. Also depicted is conveyor belt  814  which is used to transport material that is stored in silo  100  once it is erected. 
         [0072]      FIG. 9  depicts the engagement of hook plate  702  with pin  810 , in an embodiment. The hook plate  702  is attached to or part of the flipper mechanism  210  and the pin  810  is attached to the silo leg  804 . Also depicted is pin  208  (also depicted in  FIG. 2 ) which serves as a swivel point about which the flipper mechanism  210  rotates. 
         [0073]      FIG. 10  depicts a configuration in which the silo  100  is free standing and disengaged from the flipper mechanism  210 . The flipper mechanism  210  has been fully retracted. 
         [0074]      FIG. 11  depicts two actuator—rocker arm—arm assemblies, with each placed on one side of trailer  1120 . In  FIG. 11 , rocker arms  1102  and  1104  are coupled to arms  1106  and  1108 , respectively. Actuators  1110  and  1112  are coupled to rocker arms  1104  and  1102 , respectively. Also depicted is flipper mechanism  1114 , pneumatic pin  1116 , and hydraulic jack  1118 . 
         [0075]      FIG. 12  depicts in an embodiment the orientation of hook plates and corresponding pins. Pins  1201 ,  1203 ,  1205  and  1207  are seated in hook plates  1202 ,  1204 ,  1206  and  1208 , respectively. Hook plates  1202  and  1208  are laterally opposed to each other. Hook plates  1204  and  1206  are laterally opposed to each other. Also depicted is conveyor belt  1209 . 
         [0076]      FIG. 13  depicts a latching mechanism engaged with a pin  1301  which is seated in hook plate  1302 . Also depicted are hinged plate  1304  with a hole which is so located such that the hole in the plate may receive the end of pin  1301 . In one embodiment, the latching mechanism comprises a spring  1312 , a hinge  1308 , a lever handle  1306  and a plate  1310  to secure the lever  1306 . 
         [0077]      FIG. 14  depicts three silos  100  positioned side-by-side on a base platform  106 . Also depicted are shuttle conveyors  814  which are located under the exit ports beneath each silo  100  such that the shuttle conveyor may be used to transfer material stored in silos  100  onto a dual belt conveyor  1401  or other receiving mechanism that delivers the material to a container, hopper or blender hopper  1402 . The dual belt conveyor system  1401  is used, in certain preferred embodiments, to transport the material stored in the silos  100  into a container, storage bin, hopper or blender hopper  1402 . Each of silos  100  may comprise one or more filler tubes  1403  that allows for filling of the silo with proppant or other material. 
         [0078]      FIG. 15  depicts two silos  100  vertically positioned on two separate, neighboring base platforms. In between the two silos is a dual belt conveyor. The dual belt conveyor system is used, in certain preferred embodiments, to transport the material stored in the silos  100  into a blending or storage bin (not depicted). 
         [0079]      FIG. 16  depicts six silos  100  vertically positioned on two separate base platforms (in a “six pack” configuration). In between the two rows of three silos is a dual belt conveyor system  1401  that is fed by the shuttle conveyors  814  beneath each silo  100 . The dual belt conveyor system  1401  as well as the shuttle conveyors  814  may be electronically controlled using a variable frequency drive that allows for variable speeds of the conveyors. The dual belt conveyor system  1401  is used, in certain preferred embodiments, to transport the material stored in the silos  100  into a container, storage bin, hopper or blender hopper  1402 . Each of silos  100  may comprise one or more filler tubes  1403  that allows for filling of the silo with proppant or other material. 
       Deployment of Silo 
       [0080]    To deploy a silo in one embodiment of the instant invention, a trailer  102 , upon which is mounted a silo  100 , is backed up onto the surface of a base platform  106  using a truck  104  that is coupled to a trailer  102 . In a preferred embodiment, the tires of the trailer  102  are kept aligned and properly oriented via guiderails on the surface of the base platform  106 . Optionally, tire stops may be employed to halt the movement of the trailer  102  at a desired position on the base platform  106 . 
         [0081]    Once the trailer  102  is in a desired position on the base platform  106 , the rear end of the trailer (the end of the trailer  102  furthest away from the truck  104  in  FIG. 1 ) is raised using hydraulic jacks that in an embodiment may be located and attached on either side of trailer  102 . For example, in an embodiment hydraulic jack  108  of  FIG. 1  and  FIG. 9  and additionally a second hydraulic jack located at a corresponding location on the other side of trailer  102  from hydraulic jack  108  may be used to raise the rear end of the trailer about 8-10 inches depending on the ride height suspension of the trailer. In a preferred embodiment, hydraulic foot  110 , and a second hydraulic foot located at a corresponding location on the other side of trailer  102  from hydraulic foot  110 , are set to provide added structural support for the trailer  102  so it does not twist out of shape during raising or lowering of the silo  100 . The purpose of the hydraulic jacks and hydraulic feet is two-fold: 1) they allow raising of the rear end of the trailer by an amount that provides room to swivel or rotate the silo around pivot point  208  so that the feet at the base of the silo can then be lowered down vertically to rest on the surface of base platform  106 ; and 2) they provide stability to the trailer  102  as the silo  100  is raised or lowered. 
         [0082]    Once hydraulic jack  108  (and a second hydraulic jack located at a corresponding location on the other side of trailer  102  from hydraulic jack  108 ) and hydraulic foot  110  (and a second hydraulic foot located at a corresponding location on the other side of trailer  102  from hydraulic foot  110 ) are set and the back of trailer  102  is elevated, the actuator  202  is engaged to push the rocker arm  204  up and raise the silo. The actuators described herein may be powered, for example by hydraulic jacks or pneumatic jacks. The size of the rocker arm  204  is optimized based on the load size of the silo and the strength of the actuator  202 , as would be apparent to one of ordinary skill in the art based on the disclosure of this specification. In one embodiment, the shape of rocker arm  204  and the position of pin  214  at the vertex of an angle was optimized over multiple iterations to account for at least three factors: 1) allowing for the silo  100  to lie as flat as possible in the travel position when mounted onto the trailer  102 ; 2) allowing a shorter moment arm in rocker arm  204  so that a sufficient force is applied through arm  206  to cause the flipper  210  to rotate, raising the silo when actuator  202  is activated. In preferred embodiments, the silo  100  is not directly attached to arm  206 . The vertical component comes from the rotation of the flipper  210 ; and 3) the force required from the actuator  202  to lift the silo to an erect configuration. The pins  212  and  214  that go through the rocker arm are in one embodiment parallel to each other. 
         [0083]    Since the front end of the trailer  102  (the end of the trailer that is closest to the truck  104  in  FIG. 2 ) is lower than the back of the trailer due to the hydraulic jacks  208  and hydraulic feet  212 , it is necessary to rotate the silo  100  greater than 90 degrees around the pivot point at  208  when the silo is to be deployed. In a preferred embodiment, the center of gravity of the silo  100 , when empty, is about two thirds the height of the silo measured from the bottom of the silo. While the silo is being lifted, once the center of gravity of the silo  100  crosses above the line formed by pivot point  208  and the corresponding pivot point (connecting the corresponding rocker arm to the trailer) on the other side of the trailer, the torque caused by the action of gravity upon silo  100  will, if not countered, cause silo  100  to fall in the opposite direction, i.e., away from and behind trailer  102 . This point at which this torque is zero (i.e., the point at which the center of gravity of the silo  100  crosses above the line formed by pivot point  208  and the corresponding pivot point on the other side of the trailer) is referred to as the “break point.” Once the silo  100  passes the “break point,” a counter balance mechanism that is a component of the actuator  202  prevents the silo from actually falling by counteracting the torque due to gravity. The counter balance mechanism is a hydraulic control device called a counter balance valve. In a preferred embodiment, counterbalance valves are a regulating mechanism on valve-powered cylinders, such as those on electrical repair trucks. The counterbalance valves serve to limit the amount of fluid change within the flange, thus preventing sudden changes in pressure and resultant instability valves work by reacting to the weight of the load as that weight is translated into pressure on the pump cylinder. For example, in a repair truck, the weight of the platform (and any repairmen within) supply the downward pressure to the cylinder. When the counterbalance valves are directly triggered by the force of the weight, which occurs when the load is being lowered or if the cylinder malfunctions, the valve restricts the amount of air or fluid that it releases. As a result of the counterbalance valve&#39;s releasing fluid gradually, the load is stabilized and prevented from falling in a completely uncontrolled manner. Counterbalance valves are used as a safety mechanism, and to keep pressure cylinders stable as they contract to lower a load or release pressure. 
         [0084]    In a preferred embodiment, the configuration of the trailer  102  during silo deployment is such that the rear end of the trailer is elevated compared to the front of the trailer. In this configuration, when the silo  100  is vertical, the break point will have been passed. In one embodiment, while the silo  100  is being raised to the vertical position, or being lowered from the vertical position, the latching mechanism depicted in  FIGS. 4B  or  13  (or in alternative embodiments, pneumatic locking pin  1116  (and a similar pneumatic locking pin located on the other side of the flipper mechanism  1114 )) are engaged to keep silo  100  firmly secured to flipper mechanism  1114 . 
         [0085]    In a preferred embodiment, the latching mechanism incorporates a hinged plate  1304  with a hole in it as depicted in  FIGS. 4B and 13 . The hinge  1308  is coupled to the flipper mechanism and is so located that the hole in hinged plate  1304  may receive the end of the pin  808 , so that the pin cannot be disengaged from the hook plates. A corresponding hinged plate that is not depicted in  FIG. 13  is oriented such that it may receive the end of pin  810 . In one embodiment, this design requires activation of the latching mechanism via a manually operated lever as depicted in  FIGS. 4B and 13 . In another embodiment, the manually operated lever may be replaced with an automatic device involving a linkage and/or a cam, using the rotation of the flipper mechanism  210  or  712  relative to the trailer  102  to engage and disengage the latch. Thus, the latching mechanism depicted in  FIGS. 4B and 13  is engaged to keep the silo secured to the flipper mechanism  210  or  712 . Other latching mechanisms could be used, such as pneumatic latching mechanisms  1116  (and a corresponding latching pneumatic latching mechanism not depicted in  FIG. 11 ). When the silo is vertical, the weight of the silo keeps the four pins,  806 ,  808 ,  810 , and  812  engaged with the corresponding hook plates attached to or part of the flipper mechanism. As the silo rotates to horizontal, however, the effect of the weight of the silo keeping the pins engaged in the corresponding hook plates is lost. Therefore, the latching mechanism keeps the silo  100  firmly secured to the flipper mechanism  210  or  712  during raising and lowering of the silo. 
         [0086]    In one embodiment, when the silo  100  is vertical, the latching mechanism depicted in  FIGS. 4B and 13  is disengaged to facilitate lowering of the silo  100  onto the surface of the base platform  106 . Prior to lowering the silo  100 , all of the weight of the silo is on the four pins  806 ,  808 ,  810  and  812 , which are engaged with the corresponding hook plates attached to or part of the flipper mechanism. At this time, it is safe to retract the manual or hydraulic foot  110  (and the corresponding hydraulic foot located on the other side of trailer  102 ). Next, the rear end of the trailer  102  is lowered by disengaging the hydraulic jack  108  and the second hydraulic jack correspondingly located on the other side of the trailer. Disengaging these hydraulic jacks lowers the trailer  102  down so that the tires on trailer  102  rest on the surface of the base platform  106 . This causes the silo  100  to also be lowered onto the surface of base platform  106  such that the hook plates attached to or part of the flipper mechanism disengage from the corresponding pins attached to the silo legs. At this point the silo is in a free-standing and vertical configuration on the base platform. 
         [0087]    In a preferred embodiment, the four feet at the base of the silo  100  are secured to the base platform  106  using turnbuckles to prevent the silo from toppling in high-wind conditions. The manner in which such turnbuckles may be configured, used and attached to base platform  106  and the four feet of silo  100  would be apparent to one of ordinary skill in the art based on the disclosure in this specification. 
         [0088]    The flipper mechanism  210  may be lowered back to a horizontal position on the trailer  102  by retracting the actuator arms. 
         [0089]    In a preferred embodiment, the silo  100  comprises one or more tubes attached to and running up the side of the silo  100  which allows for sand, proppant or water to be added to the silo. Vents at the top or sides of the silo  100  prevent the accumulation of excessive pressure inside the silo  100 . Optionally, since material to be added to the silo may include dust, a dust collector or a dust suppressor may be appropriately positioned on or near such vents to prevent dust from being released into the environment. For example, the dust collector may be self-cleaning such that dust is recycled back into the silo and not liberated into the environment to be used as needed. 
       Retracting the Silo 
       [0090]    In one embodiment of the invention, the trailer  102  is backed onto the base platform  106  such that the tires are directed in a linear path using guiderails attached to the surface of the base platform  106 . In a preferred embodiment, the trailer stops at a determined position using tire stops positioned on the base platform  106 . 
         [0091]    Once the trailer  102  is in the desired position, the flipper mechanism  210  is raised to a vertical orientation using the actuators such that the hook plates attached to or part of the flipper mechanism are aligned for engagement of the corresponding pins attached to the legs of the silo. The vertical orientation of the flipper mechanism  710  may exceed 90 degrees due to the orientation of the trailer. Prior to elevating the rear end of the trailer  102  using hydraulic jack  108  and a second hydraulic jack located in a corresponding position on the other side of trailer  102 , the hook plates  702 ,  704 ,  706  and  708  attached to or part of the flipper mechanism  710  will be lower than the pins  806 ,  808 ,  810  and  812  that are attached to the legs of the silo  802  and  804 , because the rear end of the trailer  102  has not been elevated yet. Once the flipper mechanism  710  is in position, the trailer  102  is then raised using the hydraulic jack  108  and the second hydraulic jack located in a corresponding position on the other side of trailer  102  (which are independent of each other so that the trailer can be leveled) so that the four hook plates  702 ,  704 ,  706  and  708  engage the four pins  806 ,  808 ,  810  and  812  attached to silo legs  802  and  804  and the pins are thereby seated into the bottom portions of each corresponding hook plate. The orientation of the pins and hook plates as described above assists in easily and smoothly accomplishing this engagement. The hydraulic jack  108  and the corresponding hydraulic jack on the other side of trailer  102  are used to raise the silo off the surface of the base platform  106 . The foot  110  and the corresponding foot on the other side of trailer  102 , which in a preferred embodiment are hydraulic, are set to provide added structural stability and support. The latch mechanism  406 , or in an alternative embodiment, pneumatic pins, are reactivated to engage the corresponding holes in the silo legs. 
         [0092]    Actuators  1210  and  1212  are activated to bring the silo down from a vertical position to a horizontal position resting on trailer  102 . 
         [0093]    In a preferred embodiment, actuators  1210  and  1212  are hydraulic cylinder rods (coupled to the rocker arms  1204  and  1202 ) that are oversized so that rod head surface area on the side to which the rod is attached is less than the surface area of the rod head on the opposite side. This prevents the operator from retracting the silo  100  if it has material in it and has added weight. 
         [0094]    The silo  100  is now fully in the “traveling position.” Foot  110  and the corresponding foot on the other side of trailer  102  are now retracted and the silo  100  is fastened or shackled to the trailer  102  using turnbuckles or other load binding device. 
         [0095]    Hydraulic jack  108  and the corresponding jack on the other side of trailer  102  are now lowered such that the tires of trailer  102  are fully in contact with the base platform  106 . The operator is free to drive straight off the base platform  106 . Self-aligning hook plates and pins 
         [0096]    In one aspect of the invention, the inventors have developed a unique and highly advantageous system of hook plates and pins that allow the flipper mechanism to rotate the silo in embodiments of the invention from a horizontal position resting on the trailer to a fully vertical position resting on the base platform, and vice versa. The unique orientation of the hook plates with respect to the corresponding pins allows for the hook plates and pins to “self align” as they are being engaged by the operator. 
         [0097]    As depicted in  FIG. 8 , the pins are attached to the legs of the silo such that they form angles with respect to each other. For example, the pins  806  and  808  are attached to silo leg  802 . The orientation of the pins is such that they are attached to different faces of the silo leg  802  and form an angle of approximately 90 degrees with respect to one another. Similarly, the corresponding hook plates attached to or part of the flipper mechanism form corresponding angles with respect to each other such that they are oriented in a manner that allows for the hook plates to engage with the corresponding pins. The pins attached to silo leg  804  are similarly oriented with respect to each other. In the embodiment depicted in  FIG. 8 , pins  806  and  810  are substantially parallel to one another, and pins  808  and  812  are substantially parallel to one another. The orientation of the four pins and the four hook plates allows the hook plates and pins to “self align” when the flipper mechanism is used to engage the silo for retraction. The unique alignment of the system of hook plates and pins also provides the beneficial advantage of minimizing any movement of the silo once it is coupled to the flipper mechanism. Once the hook plates and pins are engaged, the silo is essentially locked into place and not free to slip off the flipper mechanism or be subject to any lateral movement. 
         [0098]    The present invention has been described in terms of several embodiments solely for the purpose of illustration. Persons skilled in the art will recognize from this description that the invention is not limited to the embodiments described, and may be practiced with modifications and alterations limited only by the spirit and scope of the appended claims which are intended to cover such modifications and alterations, so as to afford broad protection to the invention and its equivalents.