A hydraulic control system for linear actuation that includes an electric motor connected to a hydraulic pump and a hydraulic cylinder connected to the pump by a first flow line. A pressure transducer, a pressure control valve, and a check valve are connected to the first flow line between the pump and the cylinder and a tank is connected to the pump by a second flow line and the cylinder by a return line. A control valve is connected between the first flow line and the return line.

A multi-piston fluid pump system includes a pump head, a motor unit, and a processor, the pump head having two or more cylinders and a piston disposed within each cylinder, the motor unit configured to provide bi-directional actuation of the pistons in each cylinder in response to control signals from the processor in order to minimize fluctuations in pressure and/or flow rate at the outlet of the fluid pump system.

A multi-piston fluid pump system includes a pump head, a motor unit, and a processor, the pump head having two or more cylinders and a piston disposed within each cylinder, the motor unit configured to provide bi-directional actuation of the pistons in each cylinder in response to control signals from the processor in order to minimize fluctuations in pressure and/or flow rate at the outlet of the fluid pump system.

Power systems and methods of controlling an engine driven air compressor include an air compressor driven by an engine via a clutch. A first pressure sensor configured to sense a pressure level at an outlet of the air compressor. An inlet valve configured to close in response to the first pressure sensor sensing a pressure level above a first pressure level. In addition, a second pressure sensor to sense a pressure level below a second pressure level at a housing of the air compressor, wherein the clutch is configured to disengage in response to the second pressure level, wherein the first pressure level is higher than the second pressure level.

Power systems and methods of controlling an engine driven air compressor include an air compressor driven by an engine via a clutch. A first pressure sensor configured to sense a pressure level at an outlet of the air compressor. An inlet valve configured to close in response to the first pressure sensor sensing a pressure level above a first pressure level. In addition, a second pressure sensor to sense a pressure level below a second pressure level at a housing of the air compressor, wherein the clutch is configured to disengage in response to the second pressure level, wherein the first pressure level is higher than the second pressure level.

A method of attenuating pressure pulsations, comprises: pumping liquid into a vessel in fluid communication with a flow line by a conduit sealingly passing through a top surface of the vessel, so as to discharge the liquid into the flow line while creating an air-liquid interface in the vessel, by trapping in an upper part of the vessel air that attenuates pressure pulsations caused by the pumping. The method also comprises generating condition for the liquid to drain out of the vessel to allow air to fill at least the upper portion of the vessel.

A method of attenuating pressure pulsations, comprises: pumping liquid into a vessel in fluid communication with a flow line by a conduit sealingly passing through a top surface of the vessel, so as to discharge the liquid into the flow line while creating an air-liquid interface in the vessel, by trapping in an upper part of the vessel air that attenuates pressure pulsations caused by the pumping. The method also comprises generating condition for the liquid to drain out of the vessel to allow air to fill at least the upper portion of the vessel.

A capacity control valve includes: a valve body (10) having first communication passages (11), second communication passages (12), third communication passages (13), and a main valve seat (15a); a valve element (20) having an intermediate communication passage (29), a main valve portion (21c) and an auxiliary valve portion (23d); a pressure-sensitive element (24) disposed in the valve body (10); a solenoid (30) that drives a rod (36); a first biasing member (43) that biases in a valve closing direction of the main valve portion (21c); and a second biasing member (44) that biases in a valve opening direction of the main valve portion (21c), wherein the rod (36) moves relative to the valve element (20) to press the pressure-sensitive element (24). The capacity control valve can efficiently discharge a liquid refrigerant and can decrease a driving force of a compressor during a liquid refrigerant discharge operation.

Disclosed is a turbine fracturing apparatus. The turbine fracturing apparatus includes: a main power assembly and an auxiliary power assembly. The main power assembly includes a first power source and a piston pump connected to the first power source; the first power source outputs power to the piston pump, and the piston pump outputs a first liquid. The auxiliary power assembly includes a second power source, a load sensitive system connected to the second power source, and an auxiliary power device; the second power source outputs power to the load sensitive system, the load sensitive system is connected to the auxiliary power device and outputs a second liquid for the auxiliary power device. The first liquid is different from the second liquid, and the first liquid and the second liquid have certain pressure. The load sensitive system is configured to regulate a pressure of the second liquid in real time according to pressure of the second liquid required by the auxiliary power device.

A centrifuge system includes a centrifuge and a feed line fluidly connected to centrifuge with the centrifuge driven by a hydraulic system. The hydraulic system includes an electric motor driving a hydraulic pump connected to a fluid reservoir with the hydraulic pump providing hydraulic fluid to one or more hydraulic motors which in turn rotate the centrifuge. The system includes a pressure sensor for measuring fluid pressure and a speed sensor for measuring the rotational speed of the centrifuge. A controller can be in communication with the hydraulic system and the sensors and can receive measurements from the sensors and adjust the pressure of hydraulic fluid flowing to the one or more hydraulic motors to maintain a rotational speed of the centrifuge based on differing loads. The system can include one or more valves, controlled by the controller, which can also adjust the hydraulic pressure of the system.