A system comprises a variable displacement pump, a metering valve, a bypass line, a pressure regulating valve, a position sensor, and a control system. At least one fuel nozzle can be in fluid communication with the output line downstream of the metering valve, wherein the variable displacement pump is configured to supply fuel to the at least one fuel nozzle. The metering valve can be disposed in the output line for controlling outlet flow from the variable displacement pump. The system can also include an actuator line parallel to the variable displacement pump and connected to the output line to provide actuation pressure from pump output of the variable displacement pump.

A system comprises a variable displacement pump, a metering valve, a bypass line, a pressure regulating valve, a position sensor, and a control system. At least one fuel nozzle can be in fluid communication with the output line downstream of the metering valve, wherein the variable displacement pump is configured to supply fuel to the at least one fuel nozzle. The metering valve can be disposed in the output line for controlling outlet flow from the variable displacement pump. The system can also include an actuator line parallel to the variable displacement pump and connected to the output line to provide actuation pressure from pump output of the variable displacement pump.

A pump intake pressure control apparatus includes an intake conduit joining a pump to either a pressurized or unpressurized liquid source, a wide-range flow controller configured to control the flow of liquid through the intake conduit, pressure sensors for detecting the pressure of the liquid in the intake conduit upstream and downstream of the flow controller, and an electronic master controller programmed to receive input from the pressure sensors and to actuate the wide-range flow controller to maintain the pressure downstream of the wide-range flow controller at or below a predetermined desired value. In one embodiment of the invention, the wide-range flow controller is a branched portion of the intake conduit having a valve in each branch. In another embodiment of the invention, the flow controller is a gate valve having a stationary triangular blocking member projecting into the passage between the inlet and outlet ports of the valve.

A pump intake pressure control apparatus includes an intake conduit joining a pump to either a pressurized or unpressurized liquid source, a wide-range flow controller configured to control the flow of liquid through the intake conduit, pressure sensors for detecting the pressure of the liquid in the intake conduit upstream and downstream of the flow controller, and an electronic master controller programmed to receive input from the pressure sensors and to actuate the wide-range flow controller to maintain the pressure downstream of the wide-range flow controller at or below a predetermined desired value. In one embodiment of the invention, the wide-range flow controller is a branched portion of the intake conduit having a valve in each branch. In another embodiment of the invention, the flow controller is a gate valve having a stationary triangular blocking member projecting into the passage between the inlet and outlet ports of the valve.

A pump intake pressure control apparatus includes a conduit joining a pump to either a pressurized or unpressurized liquid source, a flow controller configured to control the flow of liquid through the intake conduit, pressure sensors for detecting the pressure of the liquid in the intake conduit upstream and downstream of the flow controller, and an electronic master controller programmed to receive input from the pressure sensors and to actuate the flow controller to reduce the pressure downstream of the flow controller to a predetermined approximate value.

A pump intake pressure control apparatus includes a conduit joining a pump to a liquid source, a flow controller configured to control the flow of liquid through the conduit, pressure sensors for detecting the pressure of the liquid in the conduit upstream and downstream of the flow controller, and an electronic master controller programmed to receive input from the pressure sensors and to actuate the flow controller to reduce the pressure downstream of the flow controller to a predetermined approximate value.