Patent ID: 7997623

Claim:
A frac tank system comprising: a) a mobile frac tank comprising i) a tank for holding fluid, the tank having a front end, a rear end, a bottom and opposite sides, the rear end of the tank being raised above an open space, ii) fluid connection means for transferring fluid into and out of the tank, iii) a frame supporting the tank, the frame extending to the back of the tank, the frame having a lower frame section extending forwardly from the front of the tank, wherein the outer boundaries of the frame and tank cooperatively establish a first rectangular space defined therein, iv) a fifth-wheel king pin carried on said lower frame section, v) a trailer-axle and wheels connected to the frame, the trailer-axle and wheels being contained entirely in said open space, under and within the length and width of the rear end of the tank, for rolling support of the back of the tank, vi) whereby the mobile tank may be releasably connected to and pulled by a fifth-wheel coupling equipped vehicle, and vii) a pair of corner fittings connected at the top front corners of the tank, and a pair of corner fittings connected at the top rear corners of the tank, the corner fittings being configured for lifting the tank with a container-lifting device, b) a front adapter removably connectable at the front of the tank, the front adapter being configured to surround a space above said lower frame section, the front adapter having front uprights on each side of the tank and corner fittings at the top and bottom of said front uprights at the upper and lower front corners of said rectangular space, and c) a rear adapter removably connectable at the back of the tank in said open space, the rear adapter being configured to surround the trailer-axle and wheels, the rear adapter having uprights on each side of the tank and corner fittings at the bottom of said rear uprights at the lower back corners of said rectangular space, d) the front and rear adapters being configured to “square-off” the ends of the mobile frac tank to a conventional intermodal shipping container size, the front and rear adapters establishing a generally rectangular support structure, whereby frac tank systems can be stacked on one another and interchangeably with conventional intermodal shipping containers with the corner fittings thereof aligned with one another.