A system mounted on a skid for use in fracturing operations is disclosed along with an associated method. The system includes a line heater on the skid to enable heating of fuel to be used with a turbine generator and includes one or more pressure regulators coupled to the line heater to enable adjustment of a pressure associated with the fuel.

A metering valve has a main inlet port and a spool movable, and a housing outlet port in a housing. The spool has a metering inlet orifice selectively aligned with the main inlet port, and a metering outlet orifice selectively aligned with the main outlet port. The main inlet port communicates with the metering inlet orifice, and the outlet port communicates with the metering outlet orifice to each provide a metering orifice. The main outlet port communicates downstream to a minimum pressure valve. The minimum pressure valve has a piston biased to a closed position by a spring force, and a line downstream of the main outlet port acting against a face of the piston in opposition to the spring force to ensure a minimum pressure moving downstream past the piston to a use. A fuel system is also disclosed.

A metering valve has a shutoff position at which it blocks flow from the metering valve outlet line from reaching an outlet to a use. A spool has a first end and a second end. The housing has a first shoulder associated with the first end and a second shoulder associated with the second end. In the shutoff position, the spool has the first end spaced from the first shoulder, and the second end spaced from the second shoulder. A fuel system for a gas turbine engine is also disclosed.

A metering valve has a shutoff position at which it blocks flow from the metering valve outlet line from reaching an outlet to a use. A spool has a first end and a second end. The housing has a first shoulder associated with the first end and a second shoulder associated with the second end. In the shutoff position, the spool has the first end spaced from the first shoulder, and the second end spaced from the second shoulder. A fuel system for a gas turbine engine is also disclosed.

A pump system for a gas turbine engine including a first pump connected to a fluid flow demand line for delivering fluid to a fluid flow demand and a second pump connected, in parallel to the first pump, to the fluid flow demand line and supplementing fluid to the actuation or burner system based on the fluid flow demand. A pressure regulating valve (PRV) is fluidly connected to the flow demand line for bypassing flow to a pump inlet pressure of the first pump and second pump, and controlling a modulated pressure flow signal to a bypass valve, wherein the bypass valve is in fluid communication with the second pump and the PRV for receiving modulated pressure from the PRV and regulating delivery of fluid from the second pump to a bypass flow line.

A pump system for a gas turbine engine including a first pump connected to a fluid flow demand line for delivering fluid to a fluid flow demand and a second pump connected, in parallel to the first pump, to the fluid flow demand line and supplementing fluid to the actuation or burner system based on the fluid flow demand. A pressure regulating valve (PRV) is fluidly connected to the flow demand line for bypassing flow to a pump inlet pressure of the first pump and second pump, and controlling a modulated pressure flow signal to a bypass valve, wherein the bypass valve is in fluid communication with the second pump and the PRV for receiving modulated pressure from the PRV and regulating delivery of fluid from the second pump to a bypass flow line.

A metering valve includes a valve body, a valve element, a rotary servo, and a stepper motor. The valve body has a valve chamber, a fluid inlet port, a fluid outlet port, a metering valve control pressure inlet port, a servo control pressure inlet port, and a servo control pressure outlet port. The valve element is movably disposed within the valve chamber and defines therein at least a control pressure chamber and a return pressure chamber. The valve element is responsive to fluid pressure in the control pressure chamber to move between a closed position and a plurality of open positions. The rotary servo is rotatable about a rotational axis to a plurality of servo positions to thereby vary fluid pressure in the control pressure chamber. The stepper motor is responsive to commands to rotate the rotary servo to a commanded servo position.

A fuel nozzle metering valve that includes a spool having an inlet port and an outlet flow port, and a retainer assembled to one end of the spool. A valve liner houses a portion of the spool. The spool is configured to move back and forth within the valve liner. The metering valve is biased in a closed position in which the outlet flow port is disposed entirely within the valve liner. The valve is opened when the spool slides within the valve liner such that some portion of the outlet flow port extends beyond an end of the valve liner. The retainer has a stepped portion configured to abut an end of the retainer at a fuel flow pressure below the expected maximum fuel flow pressure to be used in the fuel nozzle metering valve.

An engine control device may comprise a processor and a memory. The engine control device may be configured to modify a fuel flow based on a density of the fuel proximate a fuel nozzle. The engine control device may include a densimeter embedded in, or disposed proximate, the engine control device. The engine control device may include a temperature sensor embedded in, or disposed proximate, the engine control device. The engine control device may be electrically coupled to a fuel valve and/or configured to modulate the fuel valve based on a density of the fuel at the fuel valve.

An engine control device may comprise a processor and a memory. The engine control device may be configured to modify a fuel flow based on a density of the fuel proximate a fuel nozzle. The engine control device may include a densimeter embedded in, or disposed proximate, the engine control device. The engine control device may include a temperature sensor embedded in, or disposed proximate, the engine control device. The engine control device may be electrically coupled to a fuel valve and/or configured to modulate the fuel valve based on a density of the fuel at the fuel valve.