The present invention relates to a method for controlling a fuel tank arrangement (100) connected to a prime mover (101) for propulsion of a vehicle. More particularly, the fuel tank arrangement (100) comprises a first (102) and a second (104) fuel tank connected to the prime mover of the vehicle.

The present invention relates to a method for controlling a fuel tank arrangement (100) connected to a prime mover (101) for propulsion of a vehicle. More particularly, the fuel tank arrangement (100) comprises a first (102) and a second (104) fuel tank connected to the prime mover of the vehicle.

A directional control valve includes: a base and a slider longitudinally movable relative to the base. The base includes: a rectangular body having a longitudinal bore, a transverse bore, and a chamber formed at an intersection between the bores; supply and function seal plates, each having a stinger disposed in the transverse bore, one or more receptacles, and a passage extending from each receptacle through the stinger; and a supply, first function, and second function blocks, each fastened to the body and having a stinger disposed in the respective receptacle and a coupling for connection to a flow line. The slider includes: a sliding seal assembly disposed in the chamber; and an operating rod fastened to the seal assembly.

Aspects of a flow balanced frac tank farm are described herein. In one embodiment, the flow balanced frac tank farm includes at least one battery of frac tanks comprising a plurality of frac tank trailers, a header pipe arrangement, and at least one valve between one or more of the frac tank trailers and the header system. The header pipe arrangement may include a header supply pipe to supply water to individual ones of the plurality of frac tank trailers and a header discharge pipe to discharge water from individual ones of the plurality of frac tank trailers. The header pipe arrangement may be relied upon to help balance the flow of heated fluids among the frac tank trailers in frac tank farm.

A waste fluid containment and draining system may have a black waste water holding structure for holding black waste water and a grey waste water holding structure for holding grey waste water. First and second valves may be included for enabling selective emptying of the two holding structures. A macerator pump may be used which has an input in flow communication with both of the first and second valves. A discharge conduit may be in flow communication with an output of the macerator pump. A control subsystem may be in communication with the first and second valves and the macerator pump for controlling the first and second valves, together with the macerator pump, to enable selective pumping out of the holding structures by the macerator pump through the discharge conduit.

A liquid level controlling apparatus includes a plurality of main sinks, a storage sink, a pump and a connection tube. One of the plurality of main sinks includes a transmission port and a first liquid level detector. The storage sink includes a delivery port and a second liquid level detector. The pump includes an outlet and an inlet. The connection tube includes an rehydration tube and an drain tube. The rehydration tube has a first rehydration section and a second rehydration section. The first rehydration section is connected between the delivery port and the inlet. The second rehydration section is connected between the outlet and the transmission port. The drain tube has a first drain section and a second drain section. The first drain section is connected between the transmission port and the inlet. The second drain section is connected between the outlet and the delivery port.

A pressurized gas delivery system includes at least a first gas supply source and a second gas supply source. The first gas supply source is configured to supply a first pressurized gas output, and the second gas supply source is configured to supply a second pressurized gas output. A valve including at least a first position and a second position fluidly connects an outlet of the first gas supply source to a system outlet in the first position and to an inlet of the second gas supply source in the second position.