Patent Application
20150191304
This invention is in the field of water storage and in particular a transportable water storage system with a large capacity.
In some industrial applications, very large quantities of liquid are required at temporary work sites. For example in petroleum oil and gas recovery operations, it is common practice to fracture an underground formation by injecting liquid comprising water and various chemicals at high pressure into the formation. Formation fracturing operations, commonly called fracking, can require very large amounts of water, which must be gathered and stored in a temporary tank set up at the work site. Such fracking operations can require on site storage of one or even two million US gallons of water.
It is known to provide large open top tanks by erecting walls and laying a liner membrane over the ground inside the walls and up over the walls. Such open tanks can provide the required storage capacity, however are subject to leaks. A leaking liner may allow a large quantity of the contained liquid to leak into the ground, and since the contained liquid typically contains undesirable materials, significant ground contamination may occur undetected. Emptying these large tanks without spillage is also problematic.
Alternatively large metal tanks are transported to the work site where they are filled with water for use in the fracking operation. The tanks typically have a capacity of about 500 barrels or 21,000 US gallons and at the well site these tanks are placed on the ground either horizontally or vertically. The horizontal tanks typically have wheels mounted on a rear end thereof and are simply towed into position at the well site. About 50 of these tanks are then required to hold the one million US gallons required for a typical fracking operation. The area available at work site for placing these tanks is limited and becomes very crowded.
Horizontal orientation occupies considerably more of the available area, than vertical orientation, however vertical orientation typically requires specialized trailers or cranes to move the tanks, commonly called silos because of their vertical orientation, from the horizontal orientation required for transport, to the vertical orientation. A significant problem with vertical orientation is stability, as a vertical silo rests on a relatively small area provided by the end of the silo. When empty especially, they are susceptible to be being knocked over by high winds or accidental contact with other equipment moving around in the crowded work area.
Periodically such tanks must be cleaned to remove sediment and the like, typically requiring people to enter the tank.
It is an object of the present invention to provide a transportable liquid storage system that overcomes problems in the prior art.
In a first embodiment the present invention provides a transportable liquid storage system comprising a plurality of silos, each silo adapted to be moved on a transport vehicle in a horizontal transport orientation to a work site and moved to a vertical operating orientation at the work site with a silo base resting on the ground. The silos are arranged in at least two adjacent rows, and each silo is releasably and rigidly attached to all silos adjacent thereto such that the plurality of silos forms a substantially rigid silo structure, and an outlet port on each water silo is connected to a conduit, the conduit having a discharge at a selected location.
In a second embodiment the present invention provides a water silo apparatus adapted to be moved on a transport vehicle in a horizontal transport orientation to a work site and moved to a vertical operating orientation at the work site. The apparatus comprises an elongate main chamber with an outlet port in a lower portion thereof. A hollow base is attached to a lower end of the main chamber, wherein an entirety of the lower end of the main chamber rests on the hollow base when in the vertical operating position such that liquid leaking from the lower end of the main chamber collects in the hollow base, and a liquid detector is located in the hollow base and is operative to send a leak signal to a leak indicator when liquid is detected in the hollow base. An overflow chamber extends upward from a top end of the main chamber, the overflow chamber having a cross-sectional area that is less than about 20% of a cross-sectional area of the main chamber, and a vent opening is provided in an upper portion of the overflow chamber.
The transportable liquid storage system provides a plurality of liquid storage silos locked together in a silo structure that has considerable stability, which can be enhanced with folding stabilizer legs. A large quantity of liquid can thus be stored in a relatively small area at the work site. An overflow chamber allows the main chamber of each silo in the silo structure to be filled to capacity when the silos are on uneven ground maximizing the storage capacity of the structure. The overflow chamber also facilitates aeration of the liquid in the silo if necessary. The silos can include a removable hollow base which contains and detects leaks, and facilitates repairs. Scrubbers can facilitate cleaning of the silo interiors.
While the invention is claimed in the concluding portions hereof, preferred embodiments are provided in the accompanying detailed description which may be best understood in conjunction with the accompanying diagrams where like parts in each of the several diagrams are labeled with like numbers, and where:
The silos 3 are arranged in at least two adjacent rows, and each silo 3 is releasably and rigidly attached to all silos 3 adjacent thereto by upper and lower releasable locking devices 11 such that the plurality of silos 3 forms a substantially rigid silo structure. In the illustrated system 1 locking device comprises a first lock mechanism 11A on a first silo and a corresponding second lock mechanism 11B on an adjacent second silo, and the first lock mechanism 11A is adapted to releasably engage the second lock mechanism 11B. It is contemplated that the locking devices 11 could be provided by a variety of mechanisms known in the art, as an example
Orienting the silos 3 vertically reduces the area required at the worksite but vertical silos, especially when empty, have significant stability problems. Locking the silos 3 together to form the silo structure greatly increases the stability of the structure compared to a lone silo 3 resting on its base 7. Stability is further increased by providing stabilizer legs 13 movably mounted to the silos 3 such that the stabilizer legs 13 movable from a stored position P1 adjacent to a wall of the silos 3 to an operating position P2 extending outward from the silos 3 and outward from the silo structure and contacting the ground 9.
An outlet port 15 on each water silo 3 is connected through a valve 17 to a conduit 19 and the conduit 19 has a discharge 21 at a selected location where the stored liquid will be used at the work site. An issue that must be dealt with in many situations where the system will be used, such as in formation fracturing operations at well sites, is that the liquid will be drawn out very quickly, and so quite large vent openings are required at the top of each silo 3 to allow air to enter the silo as liquid is drawn off. Often all the valves 17 on the silo structure will be open to allow the liquid to drawn off quickly at the discharge 21. When the silo structure is placed on uneven ground, some silos will be higher than some others such that when the valves are all open, liquid will flow from the higher silo to a lower silo and could spill out the vents.
To avoid this and allow each silo 3 to be filled to capacity each silo 3 comprises a main chamber 23 and an overflow chamber 25 extending upward from a top end of the main chamber 23. The overflow chamber 25 is much smaller than the main chamber 23, with a cross-sectional area that is less than about 20% of the cross-sectional area of the main chamber 23, as seen in the top view of
At times it may be desirable to draw liquid out of the silo 3 at a higher level, such as to avoid sediment that may have formed in the bottom of the silo. The silo 3 in
A hollow base 7 is attached to a lower end of the main chamber 23. The entire lower end of the main chamber 23 rests on the hollow base 7 when in the vertical operating position such that liquid leaking from the lower end of the main chamber 23 collects in the hollow base 7 where a liquid detector 37 is located and operative to send a leak signal to a leak indicator 39 when liquid is detected in the hollow base 7. The hollow base 7 is fastened to the lower end of the main chamber 23 by bolts or the like so the base is removable to provide access to repair the lower end of the main chamber 23 if a leak is detected.
To facilitate cleaning the silos, lower and upper scrubbers 41A, 41B are operative to direct pressurized streams of liquid on corresponding lower and upper portions of the inner surface of the main chamber 23. Typically such scrubbers 41 will comprises a plurality of rotatable nozzles 43, and a high pressure liquid source 45 connected to the nozzles 43 to rotate the nozzles and provide the pressurized stream of liquid.
The transportable liquid storage system 1 provides a plurality of liquid storage silos locked together in a silo structure that has considerable stability, which can be enhanced with folding stabilizer legs 13. The overflow/aeration chamber 25 allows the main chamber of each silo 3 in the silo structure to be filled to capacity when the silos are on uneven ground and also facilitates aeration of the liquid in the silo if necessary.
The hollow base 7 provides leak detection and containment to prevent undetected contamination of the ground at the work site. Scrubbers 41 can be provided to clean the silo interiors, with a silo floor 35 sloping to the outlet port 15 so sediment and the like will flow to the outlet port 15.
The foregoing is considered as illustrative only of the principles of the invention. Further, since numerous changes and modifications will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly, all such suitable changes or modifications in structure or operation which may be resorted to are intended to fall within the scope of the claimed invention.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2838445 | Jan 2014 | CA | national |
