Abstract:
A mobile storage tank has a length and includes a container having first and second opposed ends and a length extending therebetween. A stairway is mounted on the first end of the container. The stairway extends transverse to the length. An auxiliary storage section forms a part of the container and extends from the first end thereof. The auxiliary storage section underlies the stairway. At least one wheel is connected to the container for transporting the tank.

Description:
FIELD OF THE INVENTION 
     The present invention relates to storage tanks, and, more particularly, to mobile storage tanks. 
     BACKGROUND OF THE INVENTION 
     Large storage tanks are often used for storing and dispensing fluids such as fracturing liquids, fluids from environmental cleanups, and various other industrial fluids. When emptied, the tanks may be towed by a truck from one site to another, where they may be refilled and reused. Various federal, state and local highway regulations limit the size of such tanks for over-the-road transport. Accordingly, there is a need for a mobile storage tank which enhances the capacity of the tank while nonetheless being capable of over-the-road transport in compliance with federal, state and local regulations. Further, there is a need for such a mobile storage tank with enhanced convenience and safety for operators and technicians. 
     SUMMARY OF THE INVENTION 
     The present invention is directed to a tank which provides enhanced storage capacity as well as improved convenience and safety for an operator, while nonetheless allowing the tank to be towed on public highways. A mobile storage tank of the present invention includes a container having first and second opposed ends and a length extending therebetween. A stairway is mounted on the first end of the container. The stairway extends transverse to the length. An auxiliary storage section forms a part of the container and extends from the first end thereof. The auxiliary storage section underlies the stairway. At least one wheel is connected to the container for transporting the tank. 
     Preferably, the auxiliary storage section is located at the first end of the container and the at least one wheel is located at the second end of the container. A pull bar may be provided on the first end. Preferably, the container includes a roof panel and an upper end of the stairway is positioned adjacent the roof panel. The container may also include a bottom panel with a lower end of the stairway being positioned substantially adjacent the bottom panel. 
     According to certain preferred embodiments, the present invention is directed to a mobile fluid storage tank having first and second opposed ends and a length extending therebetween. The tank includes a container including first and second spaced apart, opposed side walls extending along the length. A roof panel extends between the first and second side walls and along the length. A first vertically extending end wall extends between the side walls and adjoins the roof panel. A second vertically extending end wall extends between the side walls. The second end wall is spaced from and opposite the first end wall. A sloped panel extends between the first and second side walls and between the first and second end walls and connects the first and second end walls. The sloped panel extends transverse to the length. The first and second end walls and the sloped panel define an auxiliary storage section. A stairway is mounted on the container and overlies the sloped panel. The stairway extends transverse to the length. At least one wheel is connected to the container for transporting the tank. 
     Preferably, the auxiliary storage section is located at the first end of the tank and the at least one wheel is located at the second end of the tank. The container may include a second roof panel extending between the first roof panel and the second end, whereby the first roof panel and the first and second side walls define a forward storage section of the container and the second roof panel and the first and second side walls define a rear storage section. The first roof panel is positioned lower than the second roof panel. 
     A third roof panel may be provided which slopes downwardly from the second roof panel to the first end wall. A vertically extending step wall extends between the first roof panel and the third roof panel and is positioned between and spaced apart from the first and second side walls. The third roof panel, the step wall and the first side wall define a supplemental storage section of the container positioned forwardly of the rear storage section. 
     The tank may include a side reinforcing channel member secured to the first side wall and a roof reinforcing channel member secured to the second roof panel. An end portion of one of the side and roof reinforcing channel members is received and secured within a portion of the other of the side and roof reinforcing channel members. 
     The present invention is further directed to a mobile storage tank including a container having a pair of opposed, spaced apart side walls and a roof panel extending therebetween. A plurality of spaced apart cleaning access ports are formed in the roof panel along the length. Each of the cleaning access ports are adapted to receive and engage a rotary spray nozzle. At least one wheel is connected to the container for transporting the tank. The tank may further include a spray nozzle rotatably mounted in one of the cleaning access ports and operable to apply a cleaning fluid onto interior surfaces of the side walls. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a side elevational view of a mobile storage tank according to the present invention in a stationary, storing position; 
     FIG. 2 is a right side elevational view of the tank of FIG. 1 connected to a truck and in a transport position; 
     FIG. 3 is a left side elevational view of the tank of FIG. 1; 
     FIG. 4 is a top plan view of the tank of FIG. 1; 
     FIG. 5 is a front end plan view of the tank of FIG. 1; 
     FIG. 6 is a rear end plan view of the tank of FIG. 1; 
     FIG. 7 is a front, left isometric view of a container forming a part of the tank of FIG. 1; 
     FIG. 8 is a front, right isometric view of the container of FIG. 7; and 
     FIG. 9 is an enlarged, perspective, fragmentary view of the tank of FIG. 1 showing a joint between adjacent reinforcing channels of the tank. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The present invention now will be described more fully hereinafter with reference to the accompanying drawings, in which embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. In the drawings, like numbers refer to like elements throughout. 
     With reference to FIGS. 1-6, a mobile storage tank according to the present invention is shown therein and indicated generally by the numeral  10 . The tank  10  is adapted to receive, hold and dispense fluids while in a stationary position as shown in FIG.  1  and to be transported by a truck  5  or the like, typically when empty of fluid, when in a transport position as shown in FIG.  2 . 
     With reference to FIGS. 1-8, the tank  10  includes a container  50 . FIGS. 7 and 8 show the container  50  without the remaining components of the tank  10 . The container  50  has a forward section  70  and a rear section  60 . The sections  60 ,  70  have common side walls  52 . Each side wall  52  has a portion  52 A forming a part of the rear section  60  and a portion  52 B forming a part of the forward section  70 . The sections  60 ,  70  also share a common bottom panel  53  (see FIG.  5 ). Lengthwise skids  51  extend along the lower edges of the side walls  52  and support the tank  10  in the stationary position (FIG.  1 ). 
     The rear section  60  is further defined by a roof panel  62 , a roof panel  62 A, a rear panel  64  and a wheel well  66 . Wheels  12  are mounted in the wheel wells  66 . 
     The forward section  70  is further defined by the bottom panel  53 , a walkway roof panel  72 , a sloped roof panel  74 , a trapezoidally shaped vertical wall  76  between the roof panel  72  and the roof panel  74 , and a first forward, vertical wall  80  (including an upper portion  80 A). A vertical wall  54  extends from the walkway roof panel  72  to the rear roof panel  62 . The sloped roof panel  74 , the wall  76 , the upper portion  80 A of the forward wall  80 , and the upper portion of the side wall portion  52 B adjoining the sloped roof panel  74  define a supplemental storage section  75 . A second forward, vertical wall  82  and a sloped stairway panel  84  extend between the walls  80 ,  82 . The forward wall  82 , the sloped panel  84 , a forward portion of the walking roof panel  72 , and the side wall portion  52 B define an auxiliary or stairway forward extension storage section  86 . 
     Each of the aforementioned walls and panels are preferably formed of flat plate steel. Suitable methods of fabrication will be apparent to those of skill in the art upon reading the description herein. 
     A stairway assembly  40  is mounted on the sloped panel  84  and extends from the level of the short nose tank pull bar  14  to the level of the walkway roof panel  72 . A plurality of steps  42  allow the operator to access the walkway roof panel  72 . The lowered height of the walkway roof panel  72  reduces the vertical traverse of the stairway so that the slope of the stairway need not be extreme and a vertical ladder section is not required. Notably, the lower end of the stairway  40  is positioned at approximately the level of the bottom panel  53 . 
     A handrail system  30  is provided adjacent the walkway roof panel  72 . The handrail system  30  includes handrails  32  which are pivotally secured to the roof panel  72  by hinge mechanisms  32 A so that they may be folded inwardly and downwardly as shown in FIG. 2. A further handrail  33  is foldable onto the handrail  32 . A fixed handrail  43  extends along the stairway  40  on its forward side. The handrail system  30  further includes a handrail  34 , which is selectively pivotable about hinge mechanisms  34 A, to assist the operator in climbing between the front roof panel  72  and the rear roof panel  62 . 
     The roof panel  72  serves as an access walkway and a work platform. A tread plate  36  extends from the vertical wall  54  to the forward wall  82 . Preferably, the tread plate  36  has a non-skid surface and is secured directly to the roof panel  72 . The tread plate may be, for example, a tread gripping enhanced surface such as diamond plate and/or perforated (preferably with serrations) plate metal. 
     Preferably, the interior walls of the tank  50  are substantially all smooth and noncorrugated. U-shaped reinforcement channels  24  are secured by welding to the outer surface of the rear roof panels  62 ,  62 A. In the illustrated embodiment, no reinforcement channels are mounted on the roof panels  72 ,  74 . U-shaped reinforcement channel members  22  are secured by welding to the outer surfaces of the side walls  52  along both of the portions  52 A and  52 B. The channel members  22 ,  24  are preferably formed of steel. 
     With reference to FIG. 9, a joint  20  is formed between each channel member  24  and the adjacent channel member  22  at the corners between the side walls  52  and the rear roof panels  62 ,  62 A. An upper end portion  22 A of each such channel member  22  is inserted into an end portion  24 A of the adjacent channel member  24  (which extends outwardly beyond the side wall  52 ) to form the joint  20 . The overlapping portions  22 A and  24 A are welded (weld material not shown). This construction enhances the rigidity of the tank  50  while allowing the interior walls of the container  50  to be smooth and flat. The flat interior walls allow for ease of cleaning and improved application of paint or lining on the tank interior and minimize the accumulation of residue, corrosion and rust. 
     Preferably, the dimensions of the tank  10  are selected such that, when towed by the intended truck  5 , the maximum height B (see FIG. 2) of the tank  10  is no greater than 13 feet 6 inches. With reference to FIG. 1, preferably, the length RL of the rear roof panel is between about 28 and 29 feet, the length FL of the front roof panel  72  is between about 15 and 16 feet, and the length L of the tank  10  between the walls  64  and  82  is between about 43 and 44 feet. Preferably, the pull bar  14  has a length of between about 1 and 3 feet. 
     With reference to FIG. 5, the height HR from the bottom panel  53  to the rear top panel  62  is preferably between about 10 and 11 feet. The vertical drop from the rear roof panel  62  to the rear roof panel  62 A is preferably between about 2 and 6 inches. The height HF from the bottom panel  53  to the walkway roof panel  72  is preferably between about 7.5 and 8.5 feet. The height HS of the front wall portion  80 A extending between the roof panel  72  and the sloping roof panel  74  is preferably between about 1 and 1.5 feet. The vertical wall  54  preferably has a height HW of between about 1.5 and 2.5 feet. Preferably, the sloped roof panel  74  forms an angle A with respect to horizontal when the tank  50  is placed in the storing position of FIG. 1 on level, unsloped ground. 
     With further reference to FIG. 5, the width W between the side walls  52  is preferably between about 8 and 8.5 feet. The width WP of the walkway roof panel  72  is preferably between about 2 and 3 feet. Preferably, the width WS of the roof panel  74  is between about 4 and 5 feet. 
     The tank  50  provides enhanced storage capacity as well as convenience and safety for the operator, while nonetheless allowing the tank to be towed on public highways. The supplemental storage section  75  provides additional capacity when the tank is in the storing position of FIG. 1 but does not increase the peak height of the tank when being towed. The auxiliary or forward extension storage section  86  provides additional storage capacity beneath the stairway assembly  40  without interfering with the use of the stairway assembly  40 . Moreover, because the stairway assembly  40  and the sloped panel  84  extend transverse to the length of the tank, the length and overall size of the walkway roof panel  72  is maximized without requiring a steep stairway incline or a ladder. Accordingly, the operator is provided with both safe and convenient access as well as a sizable work surface. 
     With reference to FIGS. 4 and 7, three spaced apart cleaning access ports  90  are provided in the roof panels  74 ,  62 . The cleaning ports  90  each have a diameter of from about 3 to 5 inches. The ports  90  are adapted to receive rotary spray nozzles  92  (see FIG.  7 ). The spray nozzles  92  are preferably driven by air or electric motor to rotate with respect to the respective ports  90 . Suitable spray nozzles  92  include tank washer model 190AH or tank washer model 290A from Spraying Systems Co. of Wheaton, Ill. Each spray nozzle  92  may include a mounting collar (e.g., pipe flange) rotatably mounted on the spray nozzle. Suitable mounting adapters such as pipe flanges or universal adapters are mounted about the ports  90  for holding the nozzles  92 . When not in use, the ports  90  may be capped as shown in FIG.  4 . 
     Dispensing/fill valves  96  are provided in the rear panel  64  and the forward wall  82 . Manways  98  are provided in the side wall  52 , the rear panel  64 , the roof panel  62  and the forward wall  82 . Preferably, the manways each have a diameter of between about 22 and 24 inches. A fill port  97  is provided in the roof panel  62  adjacent the handrail  34 . 
     While the embodiment as described hereinabove is preferred, it is also contemplated that a stairway assembly and an auxiliary storage section underlying the stairway assembly may be provided on the rear end of the tank  10  in place of or in addition to the stairway assembly  40  and the auxiliary storage section  86  of the forward end. 
     The tank  10  may be used to store any suitable fluid. For example, the tank  10  may be used to store water, fracturing liquids, fluids collected from environmental cleanups, liquid by-products of industrial chemical processes, and the like. 
     The foregoing is illustrative of the present invention and is not to be construed as limiting thereof. Although a few exemplary embodiments of this invention have been described, those skilled in the art will readily appreciate that many modifications are possible in the exemplary embodiments without materially departing from the novel teachings and advantages of this invention. Accordingly, all such modifications are intended to be included within the scope of this invention as defined in the claims. In the claims, means-plus-function clauses are intended to cover the structures described herein as performing the recited function and not only structural equivalents but also equivalent structures. Therefore, it is to be understood that the foregoing is illustrative of the present invention and is not to be construed as limited to the specific embodiments disclosed, and that modifications to the disclosed embodiments, as well as other embodiments, are intended to be included within the scope of the appended claims. The invention is defined by the following claims, with equivalents of the claims to be included therein.