A mobile machine comprising an object to be driven, an electric storage, an electric motor connected to the electric storage, a hydraulic pump driven by the electric motor, a hydraulic piston assembly hydraulically connected to the pump and comprising a housing having a first chamber, a second chamber, a piston separating the first and second chambers, and an actuating rod connected to the piston and the object to be driven, the hydraulic piston assembly configured to actuate the object to be driven relative to the mobile machine within a range of motion, and wherein actuation of the object to be driven relative to the body portion of the mobile machine within the range of motion is controllable by the electric motor and powered via the electric storage.

An assembly for machine leveling including a plurality of hydraulic cylinders having upper ends adapted for supporting the machine's base, a lower end, a shaft, and a port opening the cylinder; branch conduits having cylinder ends and pump ends, each branch conduit connecting to one of the ports; first shutoff valves connected to the branch conduits for alternatively permitting and resisting fluid flow within the branch conduits; a manifold conduit connected to the branch conduits; a hydraulic pump connected to the manifold conduit and adapted for raising hydraulic pressure within the manifold conduit to a shaft extending pressure; and an electrically modulated variable pressure relief valve connected to the manifold conduit and adapted for raising and lowering the hydraulic pressure.

The hydraulic drive system includes a hydraulic pump, a plurality of variable displacement actuators, and a control unit. The hydraulic pump discharges a hydraulic fluid. The variable displacement actuators each receive a pressure of the hydraulic fluid discharged from the hydraulic pump to operate corresponding one of a plurality of drive parts. The control unit controls displacement varying parts of the variable displacement actuators. The control unit controls the displacement varying parts of the variable displacement actuators, based on sensed pressures in fluid inflow parts of the variable displacement actuators in operation, such that the pressures in the fluid inflow parts of the variable displacement actuators in operation approach a common target pressure.

A method of calibrating an electrohydraulic valve is disclosed. The method includes actuating an on-off valve to an open position. A speed of a fixed displacement pump is regulated to establish a desired flow rate at an outlet of the pump. The pump is in fluid communication within a closed loop circuit with the on-off valve and the electrohydraulic valve. A target pressure in the closed loop circuit is determined as a function of the desired flow rate. The method further includes increasing a current to the electrohydraulic valve and monitoring the target pressure in the closed loop circuit. A start of a fluid flow through the electrohydraulic valve is determined based on a drop in the target pressure within the closed loop circuit.

A method of controlling a plurality of downhole tools in a wellbore, using first and second codes transmitted by hydraulic line to first address and then actuate the desired tool. A dedicated line is provided for terminating all actuated tools.

Some embodiments of the present disclosure provide a power system and a fracturing device. The power system includes an oil tank, a reduction gearbox and a hydraulic system. The reduction gearbox is provided with a lubricating system, and the lubricating system is communicated with the oil tank. The hydraulic system includes a hydraulic actuating member, and the hydraulic actuating member is communicated with the oil tank.

A hydraulic tool that executes a sequence of operations includes: a motor; a pump; hydraulic fluid driven by the pump; a chamber in fluid communication with the hydraulic fluid; a ram movably positioned at least partially in the chamber according to the hydraulic fluid and pressure thereof; a primary trigger configured to cause, upon actuation thereof, activation of the motor thereby causing: the pump to move hydraulic fluid from the reservoir into the ram chamber, extending the ram; a control system; and at least one sensor in communication the control system. When the primary trigger is user actuated and the ram is fully extended or the tool is clamped around a work piece, the pump continues to pump fluid, under at least partial control by the control system, until a threshold condition is determined by the at least one control system using the at least one sensor.

A control device of a pneumatic element includes a supply circuit supplying compressed air to an inlet of the pneumatic element. The control device includes a normally closed monostable valve having an inlet connected to a compressed air source and an outlet connected to the inlet of the pneumatic element. A bistable valve has an inlet connected to the compressed air source and an outlet connected to a first control port of the normally closed monostable valve. A normally open monostable valve has a first inlet connected to the compressed air source and an outlet connected to a second control port of the normally closed monostable valve. The first and second control ports controls the opening and closing of the normally closed monostable valve. The valves are operable control the flow of compressed air.

An intermittent air discharge fluid circuit includes a main valve including a discharge pilot chamber and a pilot valve including an air supply pilot chamber. The main valve is switched between a first position in which the air supply pilot chamber is connected to an air supply source and a discharge port is open to atmosphere, and a second position in which the air supply pilot chamber is open to atmosphere and the discharge port is connected to the air supply source. The pilot valve is switched between a first position in which the discharge pilot chamber is open to atmosphere and a second position in which the discharge pilot chamber is connected to the air supply source.

A flow distribution control method for a hydraulic system, the hydraulic system comprising N loops L1-LN. The flow distribution control method comprises the following steps: S1: comparing pressures P1-PN at an inlet of an actuator in each loop of the hydraulic system; S2: according to the comparison result, determining a loop Lp1 which requires flow compensation; and S3: conducting flow compensation on the loop Lp1 according to the theoretical flow of the loop Lp1 and an actual flow in the loop Lp1 which flows into the actuator, wherein the number of loops in the loop Lp1 is less than or equal to N. Also disclosed are a flow distribution control device and a flow distribution control apparatus for the hydraulic system, the hydraulic system and a non-transitory computer-readable medium. An electric control pressure pump and a flow supplementing valve are employed to replace a constant pressure difference valve, and the flow of all branches may be supplemented, thereby avoiding the phenomenon of unequal flow distribution being generated due to flow distribution characteristics of a pressure compensation system being affected by the overflow area of the constant pressure difference valve. The foregoing employs a flow compensation scheme, has a simple structure, is insensitive to pollution, and has low investment costs.