Abstract:
Applicant provides a novel tank and trailer assembly adapted to receive fluids, including frac fluids therein, at a wellsite. The frac tank of the tank/trailer assembly is comprised of a fabric composite material rather than steel. This makes the frac tank lighter and easier to haul (empty) over the highway. The frac tank and trailer assembly disclosed may even be hauled with a pickup truck and may use a gooseneck or fifth wheel connection.

Description:
[0001]    This utility patent application claims priority to and benefit of U.S. Patent Application Ser. No. 61/490,268, filed May 26, 2011. 
     
    
     FIELD OF THE INVENTION 
       [0002]    Frac tanks, namely, a frac tank assembly comprising a composite tank and a trailer adapted to carry the composite tank. 
       BACKGROUND OF THE INVENTION 
       [0003]    Frac tanks are used in the oil field for providing fluids to oil wells or for storage of fluids. The fluids may be water, salt water, acids from drilling muds, and the like. 
         [0004]    Prior art frac tanks are typically cylindrical or rectangular and made of steel and configured and shaped so that they can be pulled by a tractor, diesel, semi-truck or other suitable vehicle. Most steel frac tanks have a single axle with multiple wheels at a removed end thereof and are engaged with the tractor to pull them to and from the oil field. At a receiving site, a multiplicity of the frac tanks are typically used to receive fluids for use with the well. For the fluids received in the frac tank are subsequently emptied into road-going tankers which take it for offsite disposal. 
       SUMMARY OF THE INVENTION 
       [0005]    Applicant provides a novel frac tank and trailer assembly, wherein the frac tank is comprised of a composite substrate material, such as fiberglass, rather than steel and wherein the trailer is uniquely adapted to carry the frac tank with a number of features novel to frac tank and trailer assemblies with the weight advantage of Applicant&#39;s composite tank, a winch truck is not needed. 
         [0006]    A frac tank/trailer combination is disclosed typically comprising a pickup truck or a tractor, a frac tank assembly including a frac tank constructed from a fiberglass or composite material, and a trailer assembly adapted to engage a pickup truck or tractor. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]      FIG. 1  is a front elevational view of Applicant&#39;s tank/trailer assembly without the gooseneck assembly thereon. 
           [0008]      FIG. 2  is a side elevational view of the tank/trailer assembly. 
           [0009]      FIGS. 2A and 2B  are side elevational views of two embodiments of the rear axle assembly, fixed in  FIG. 2A , and pivoting in  FIG. 2B .  FIG. 2A  also illustrates the tank/trailer assembly with a pickup truck engaged therewith.  FIG. 2C  is a perspective, partly cutaway view of a composite frac tank having internal strengthening members. 
           [0010]      FIG. 3  is a rear elevational view of Applicant&#39;s tank/trailer assembly with the pivoting rear axle assembly embodiment. 
           [0011]      FIGS. 4A and 4B  are partial side elevational views of the pivoting rear axle assembly;  FIG. 4A  in a use position;  FIG. 4B  with the tank resting on a support surface, such as the ground. 
           [0012]      FIGS. 5 and 6  are top and side elevational views of the tank assembly separate and apart from the trailer assembly. 
           [0013]      FIGS. 7 ,  8 , and  9  are top elevational, cross-section and side elevational views of the trailer assembly apart from the tank assembly. 
           [0014]      FIGS. 10 and 11  are top elevational and side elevational views of Applicant&#39;s tank and trailer assembly illustrated in a manner in which the two elements are secured to one another. 
           [0015]      FIGS. 12 and 13  illustrate detail views of the securement straps which affix the tank member to the trailer assembly to the longitudinal members thereof. 
           [0016]      FIG. 14  is a side isometric view of the tank and trailer assembly at the front portion thereof showing the manner in which the tank and trailer assembly engage one another. 
           [0017]      FIGS. 15 and 16  are side and rear elevational views, respectively, having an alternate preferred embodiment of Applicant&#39;s invention 
           [0018]      FIGS. 15A and 16A  are side elevational views of two embodiments of Applicant&#39;s frac tank and trailer assembly. 
           [0019]      FIG. 17  is a side elevational view of Applicant&#39;s tank/trailer assembly having configured frame members, resting on the ground and containing a stored fluid. 
           [0020]      FIGS. 18 and 19  show two methods of manufacturing a frac tank member. 
           [0021]      FIGS. 20 and 21  illustrate cross-sectional views of part of the walls of Applicant&#39;s frac tank member. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0022]    This patent application incorporates by reference U.S. Pat. Nos. 4,406,471 (Holloway, 1983) (rear wheels lower), and 5,628,425. 
         [0023]      FIGS. 1 ,  2 ,  2 A,  2 B,  3 ,  4 A and  4 B illustrate various views of Applicant&#39;s novel tank/trailer assembly  10 . Applicant&#39;s tank/trailer assembly  10  may be adapted to be carried by a pickup truck PUT or tractor as more particularly set forth below. 
         [0024]    A tank assembly  100  is provided in combination with a trailer assembly  200  and other related structures which may compromise Applicant&#39;s tank/trailer assembly  10 . Tank/trailer assembly  10  is designed to engage, in one embodiment, a pickup truck PUT (see  FIG. 2A ) and to easily and effectively transport a novel empty tank assembly  100  on the unique trailer assembly  200 , which trailer assembly is adapted to both effectively carry a load and to secure a walled tank member  102  (empty) of the tank assembly  100  thereon. Tank assembly  100  functions as frac tanks in the prior art are known to function, that is, to receive waste fluids at a well site and to retain them until they may be emptied in ways known in the art. 
         [0025]    It is seen that tank assembly  100  may include an impermeable walled tank member  102 . Walled tank member  102  is typically comprised of walls, impermeable with respect to typical frac liquids received therein. Walled tank member  102  may be any shape, rectangular, cylindrical or the like. In a preferred embodiment, it is comprised of a generally cylindrical shaped member, which may have a tube portion  102   a , a front wall portion  102   b , and a rear wall portion  102   c . Strengthening members or straps  103  are typically built into the tank member  102  during construction thereof. They may be built into the walls as the composite is laid up or may attach to the outside after the tank is completed. In one embodiment, the strengthening straps are metal and external, and not integral with the composite walls. They may be external or internal.  FIG. 2C  shows internal straps  103  configured of a composite, such as fiberglass, laid in and integral with the walls. in the form of multiple rings  103   a . All the portions  102   a / 102   b / 102   c / 103  may be integral with one another and are dimensioned so that they may be received on trailer assembly  200  and carried over the highway. Typical dimensions of tank member  102  may include length L equals about 24 feet to 42 feet; height H equals about 8 feet to 12 feet. Weight of the tank assembly  100  may be about 5,000-10,000 pounds (empty) with the entire tank/trailer assembly being between about 7,000-15,000 pounds (empty). 
         [0026]    Turning to  FIGS. 20 and 21 , it is seen that impermeable walled member  102  may be uniquely comprised of a composite material  400 . Composite material may be a substrate  402  of fiberglass fabric, carbon fiber fabric, Kevlar or other suitable composite materials. Fiberglass or other substrate may comprise one or a multiple of fabric sheets which are laid up over a suitable mold, and which may be bound by a gel or resin  404 . The fiberglass may be laid up on mold M from multiple sheets of cloth, whole or chopped, and covered or impregnated with resin  404  (see  FIG. 19 ). The fiberglass or other material may be sprayed from a chopper gun or applied by winding a fiber or filament single or multi-strand substrate on a mandrel (see  FIG. 18  and the U.S. Pat. No. 5,628,425 incorporated herein by reference) or in other ways known in the art. The use of fiberglass or other suitable composite provides a weight savings without a significant loss of strength, allowing the use of a pickup truck rather than a tractor to pull the tank/trailer assembly  10 . 
         [0027]    In one embodiment, side wall thickness are: about ¼″-1″ thick; preferably about ⅜″-¾″, most preferably about ½′ thick. End walls  102   b / 102   c  or caps add about ¼″. One unique resin  404  that may be used partly or entirely is a vinyl ester  404   a , which resin may be particularly resistive of certain acidic corrosive liquids that may be carried in the tank assembly  100 . This may, typically, coat the inner walls of the tank member  100 .  FIG. 21  shows inner portions of some or all of the walls having vinyl ester resin  404   a , but vinyl ester resin may be all or part of the resin used. In  FIG. 21 , the vinyl ester is the inner ⅛″-¼″ of the wall thickness. 
         [0028]    Other inner wall coatings or resins may be used on the inner surface of walled member  102 , which coatings may further protect the composite or fiberglass material comprising the walled members from attack by corrosive liquids (like acids) held therein. These coatings include: Halogenated unsaturated polyester (HAL), Bisphenol A (BIS A), propylene glycol/isophthalic acid (PG/PIA), and Eastman TMPD™ glycol/propylene glycol/isophthalic acid (TMPD™/PG/PIA). 
         [0029]    In one embodiment, a half inch side wall has ⅛″ inner resin coating of vinyl ester and the remainder is isothermic polyester resin. 
         [0030]    Walled member  102  typically comprises a multiplicity of openings that are functionally and structurally and locationally positioned as is found in the prior art. For example, tank assembly  100  may include main top opening  104  having a removable main top opening cover  106 . An air vent/overflow  108  may be provided as may a fill pipe  110 . Inspection openings (man ways)  112  may be provided with a removable cover  114 . Drain openings  116  with a drain opening cover may also be provided. Typically a discharge manifold  120  is provided with a multiplicity of discharge manifold openings  122 . A manifold connect tube  124  may be provided. A multiplicity of discharge openings would provide for rapid discharge filling of the frac tank with liquids. Stairs  121 , such as those made of steel, may be used as known in the art. 
         [0031]    A trailer assembly  200  is provided, seen apart from the tank/trailer assembly  10  in  FIGS. 5-13 . Trailer assembly  200  may include a truck engagement assembly  202  at the front thereof, which truck engagement assembly is, in a preferred embodiment, a gooseneck or fifth wheel arrangement adapted to engage a pickup truck or tractor. Because Applicant&#39;s use of a lightweight, durable, fiberglass or composite material for walled member  102 , sufficient weight savings is provided so that a pickup truck may be used to haul tank/trailer assembly  10 . With pickup truck PUT being used, a gooseneck apparatus  203  may be included in truck engagement assembly  202 . 
         [0032]    At the removed end is seen a rear axle assembly  204 , the details of which are set forth below. Between truck engagement assembly  202  and rear axle assembly  204  is a tank support assembly  206 . It may be comprised of a multiplicity of longitudinal members, here, longitudinal members  208   a / 208   b . Longitudinal members are typically spaced apart to receive and support the cylindrical walls as illustrated in  FIG. 1 . Longitudinal members  208   a / 208   b  typically extend up to about the length L of the tank and typically slightly beyond and engage front cross-brace  212  of the front and rear cross-brace  214  at the rear so as to provide a rigid boxlike structure to cradle the underside or the lower portion of walled member  102  when a cylindrical configuration is used, with the cross-members typically bracketing the tank to prevent excessive fore and aft movement of the tank on the trailer. 
         [0033]    Turning to  FIG. 2A , it is seen that jack assembly  216  may be provided engaging the rear of the trailer assembly, for example, at one or both longitudinal members  208   a / 208   b , as well as jack assembly  218  for engaging the front of the trailer assembly. Rear jack assembly may be used whenever it is necessary to raise the rear of the tank. Front jack assembly  218  may be used when it is necessary to remove the front tank/trailer assembly  10  from the pickup truck and set the tank/trailer assembly on the ground at the well site. 
         [0034]    There may be two different embodiments of rear axle assembly  204 . Here, a first embodiment  204   a  is seen in  FIG. 2A , and a second embodiment  204   b  is seen in  FIGS. 2 ,  2 B,  4 A, and  4 B. 
         [0035]    In embodiment  204   a , rigid uprights  220  spaced apart, extend from cross-member and/or removed ends of the longitudinal members and have a rigid axle platform  222  engaged so as to form the structure illustrated in  FIG. 2A . This is a rigid structure and axle  224  is mounted to any number of structural members, typically  222  and/or elements  220  in known ways. In embodiment  204   a , a jack, such as jack  216 , may be used when raising the rear of the trailer as desired. 
         [0036]    The rigid structure, with an axle that does not drop down as set forth in embodiment  204   b , may be used without the jack at the rear. This is done by dimensioning the lowest point of the trailer assembly such that when the assembly is disengaged from the tow vehicle, and the front is lowered to the ground by the use of, for example, front jack  218 , the tank cradle or frame may rest on the ground. That is to say, as with some present steel frac tanks having fixed (non-pivoting) rear axles, removal of the front hitch and lowering the frac tank cradle or frame to the ground allows the rear axle and the wheels to be unloaded, since the tank cradle or frame rests on the ground. In the tank/trailer assembly  10  disclosed, the same configuration may be used with the removal from the tow vehicle and lowering of the front of the assembly allowing the rear to touch and unload the rear axle and wheels. This is typically done at the well site with an empty frac tank, which is then filled and emptied as known in the art.  FIG. 17  shows angled longitudinal members as known in the art. These are typical with steel frac tanks with non-dropdown rear axle assemblies. 
         [0037]    Turning now to embodiment  204   b , it is seen that pivot platform  226  is provided which is pivotally engaged to rigidly mounted standoffs  228 . Standoffs  228  are typically angled as seen in  FIGS. 4A and 4B , and may be mounted to rear cross brace  214  or other elements. Pivot bearing means  230  may be provided between the removed end of element  228  and the near end of platform  226 . A hydraulically/pneumatically actuated cylinder member  232  may be provided between rigid or fixed elements  228 / 214  or at  208 , and pivoting element  226 . Pivot platform  226  will engage, through suspension means  229 , such as shock absorbers, leaf springs, and the like, or in other ways known in the art, axle  224 . Providing pivoting action between pivot platform  226  and rigid, fixed or non-moving elements of the trailer assembly allows the operator to lower the trailer assembly  200 , such as would be desired at a well site location through activation of cylinder member  232 . 
         [0038]      FIGS. 2A and 2   b  also illustrate that a turbine  406  may engage the walls of the tank and extend into the tank interior. Turbine  406  injects O 2  or other reactant gas into the fluids therein for the purpose of reclamation and recycling of polluted and contaminated fluid. One such turbine is Toring Model TT200 available from Varacorp, Austin, Tex. 
         [0039]    Turning to  FIGS. 5 and 6 , a multiplicity, here five, hold down straps  126 , may be provided as part of the tank assembly whose function it is to secure tank assembly  100  to trailer assembly  200 . Securement straps  126  are seen in  FIGS. 5 and 6  (strengthening bands  103  not shown). The securement straps  126  are typically cylindrical (for a cylindrical tank) or otherwise conforming to the shape of the tank and may have ears  128  projecting outward as seen in  FIGS. 6 and 14  to engage the longitudinal members  208   a / 208   b  through the use of fasteners  129  through holes in the ears/frame as seen. This will keep the tank from separating from the trailer while it is being transported. Also illustrated in these figures are step assembly  131  to provide the operator with access to main top opening  104 . While the step assembly is seen attached to the tank assembly  100 , it is typically separately attached after the tank assembly  100  is attached to the trailer assembly  200  as set forth herein, through the use of mounting elements  133  and fasteners for engagement with elements, truck engagement assembly (see  FIGS. 2A and 2B ) or in other suitable ways. 
         [0040]      FIGS. 7 ,  8 , and  9  illustrate trailer assembly  200  without the tank assembly  100  engaged therewith. Trailer assembly  200  is seen to include longitudinal members  208   a / 208   b , cross-members at cross braces  212  front and  214  rear, and further to include a multiplicity of cradle members  232  formed, as best seen in  FIG. 9 , to receive the bottom portion of a curved or otherwise configured wall tank member  102 . These may provide additional vertical support to the tank member beyond that of straps  126 , which are intended to secure the tank to the trailer. Further, cradle members  232  will provide cross bracing and additional support when the tank is a positioned against the ground when it is in use at a well site as seen in  FIG. 4B . The trailer assembly is usually configured such that, when it is lowered to the ground at a wall site, the elements of the trailer assembly will keep the tank member off the ground. Lowering the trailer assembly to the ground may be achieved with the moveable rear axle assembly and/or configuring the frame elements low enough to the ground to allow safe transport over the highway yet, when the front of the trailer assembly is unhitched from a tow vehicle and lowered, the longitudinal members and/or the cross-members will keep the tank off the ground. 
         [0041]      FIGS. 15 and 16  illustrate an alternate embodiment of Applicant&#39;s tank/trailer assembly  12 . In this alternate embodiment, a standard, commercially available flatbed trailer  301 , single or dual axle, is used, typically having a gooseneck or fifth wheel assembly  302  on the front thereof and, optionally, jacks  304 / 306  included. Here, tank assembly  100  may be secured to the trailer using securement straps  308 , which will typically encircle much of the tank assembly  100 . In addition, a multiplicity of cradle blocks  210  may be used between the bed of the flatbed and the curved underside of a round tank member  102 . 
         [0042]      FIG. 17  illustrates that Applicant&#39;s novel tank/trailer assembly  10  may be used, in an alternate embodiment, rather than with a gooseneck, simply hooking up to a rear end hitch of a tow vehicle, such as pickup truck PUT. Further, a fifth wheel may be used to engage the trailer to a PUT or tractor. 
         [0043]    Examples of possible sizes, weights, and shapes are listed below:
       Small (cylindrical): 8′ diameter (height)×30′ long approx. 260 barrels Tank weight: 3300 lbs. Trailer weight: 5000 lbs.   Full size (cylindrical): 10′ diameter (height)×34″ long approx. 500 barrels Tank weight: 4500 lbs. Trailer weight: 6000 lbs.   Full size (rectangular): 8′ wide×9′ tall×40′ long approx. 500 barrels Tank weight: 6500 lbs. Trailer weight: 6500 lbs.       
 
         [0047]      FIGS. 15A and 16A  illustrate tank/trailer assembly  10  comprising tank assembly  100   a  and trailer assembly  200 . In the embodiment illustrated, retractable wheel assemblies  234  are provided for engagement through bracket  236  to longitudinal members  208   a / 208   b  (only the right side assembly  234  is shown). Retractable wheel assembly  234  includes a stub axle  236  mounted through bracket  236  or other hardware to a hydraulic assembly  238 , which typically includes one or more hydraulic elements and rigid elements in the nature of retractable gears on an aircraft. Retractable wheel assemblies  238  typically do not use a straight through axle and thus allows the retraction of tires  240  and the subsequent lowering of the frame of the trailer assembly to the ground when the tank/trailer assembly is transported to the worksite. 
         [0048]      FIG. 16A  illustrates how cables  310  with T-hooks  312  thereupon may be used to engage hook eyes  314  attached to or built into walled member  102  in order to remove, as by a crane or other mechanical device, the tank assembly  100  from the trailer assembly  200 . This may be done after removing the securement straps or other members which engage the walled tank member to the trailer assembly, as by fasteners or the like. 
         [0049]      FIG. 17  illustrates the assembly  10  at a worksite, resting on the ground. A stored fluid SF having a fluid level L is shown in the interior of the walled composite tank member  102 . The stored fluid may be: fracking fluids, hydrochloric acid or other corrosive or contaminated fluids. 
         [0050]    Although the invention has been described with reference to a specific embodiment, this description is not meant to be construed in a limiting sense. On the contrary, various modifications of the disclosed embodiments will become apparent to those skilled in the art upon reference to the description of the invention. It is therefore contemplated that the appended claims will cover such modifications, alternatives, and equivalents that fall within the true spirit and scope of the invention.