A hydraulic pressure control device comprising: a hydraulic sensor provided between a hydraulic pump and a load; a speed command arithmetic unit configured to output a speed command value Vc based on a difference between a hydraulic pressure detection value Pd from the hydraulic sensor and a hydraulic pressure command value Pc; a torque command value arithmetic unit configured to calculate a torque command value Tc based on a difference between a speed detection value Vd of a motor and the speed command value Vc; a current controller configured to control current of the motor based on the torque command value Tc; and a hydraulic pressure abnormality detector configured to detect whether a hydraulic circuit has abnormality based on the speed command value Vc and an operating condition of the load of the hydraulic circuit commanded from an upper-level control device.

An electric oil pump device includes an electric oil pump driven by a motor and a microcomputer that adjusts a control parameter of feedback control related to a motor current value or a motor rotation speed based on an oil temperature estimated based on a relationship between at least one of a hydraulic pressure, the motor current value, or a torque of the electric oil pump and at least one of an oil discharge amount or the motor rotation speed of the electric oil pump.

An efficient five-cylinder drilling pump system, includes a solid control system and a drilling rig provided, belonging to the technical field of petroleum drilling equipment; wherein the system includes a drilling pump group, a frequency conversion control room and a pump health system; the drilling pump group includes a base, the base is provided with a transmission assembly, a power end assembly, a hydraulic end assembly and a lubrication system; the frequency conversion control room is used to provide frequency-changing AC power for the transmission assembly, and realize the control and operation of the drilling pump group, the pump health system includes a power end health diagnosis system and a hydraulic end health diagnosis system; a high-power five-cylinder drilling pump system, a solids control system and a drilling rig of the present invention can monitor the pumping equipment in real time, and use electronic monitoring to monitor the pumping equipment in real time. Track pump performance parameters, display pump health status in real time, provide predictive pump inspection instructions, reduce unpredicted equipment downtime, improve equipment stability and reduce overall maintenance costs.

A method of driving a pump is used in a pressure-applying apparatus, the apparatus including a flow passage, a pump configured to impart pressure into the flow passage, an opening and closing valve configured to open and close the flow passage, a pressure detector configured to detect pressure in the flow passage, and an atmospheric air open valve configured to open an interior of the flow passage to atmospheric air. The method includes driving the pump after closing the opening and closing valve and opening the atmospheric air open valve, and evaluating a state of the pump, based on one of: the pressure detected by the pressure detector at a time at which a predetermined time period has elapsed after closing the atmospheric air open valve, and a time from closing of the atmospheric air open valve until detection of a predetermined pressure by the pressure detector.

A work machine pump control system includes: a pump horsepower control valve (22) which causes a first urging force determining a limited horsepower (F) of a hydraulic pump and a second urging force due to a delivery pressure of the hydraulic pump to act on a spool in opposition to each other and which controls the pump flow rate such that it does not exceed the limited horsepower (F); a target pump flow rate computation section (42) computing a target pump flow rate based on an operation pressure (px) and a load pressure (py); a target horsepower computation section (41) which computes a required horsepower (Freq) corresponding to an operation pressure (px) from a relationship related to the operation pressure (px) and which computes a target horsepower (Ftar) based on the required horsepower (Freq); and a pump horsepower control section (35) which controls the pump horsepower control valve (22) such that the target pump flow rate (Qtar) is delivered with the limited horsepower (F) determined by the pump horsepower control valve (22).

The present invention relates to diaphragm pump (1) having a delivery chamber (3) and a working chamber (5), wherein the working chamber can be or is filled with a hydraulic fluid and is operatively connected to a pressure generating device in order to apply an oscillating pressure to the hydraulic fluid, further comprising a diaphragm (11) having at least one diaphragm layer (13) and a diaphragm core (15), which separates the delivery chamber (3) and the working chamber (5) from each other, wherein the diaphragm (11) is or can be operatively connected to a diaphragm return device (17) comprising a pull rod (19), which applies or can apply a return force on the diaphragm (11) in the direction of the suction stroke position, and further comprising a storage chamber (21) for holding the hydraulic fluid, and wherein the working chamber (5) and the storage chamber (21) are connected to each other by means of a return flow channel (25) closed by means of a closure element (23, 23), and wherein the closure element (23, 23) is operatively connected to the diaphragm core (15) and the diaphragm return device (17), so that the return force and a pressure force counteracting the return force as a result of the fluid pressure in the working chamber (5) act on the closure element (23, 23), and wherein, when a predetermined triggering force is exceeded as a sum of the return force and the pressure force on the closure element (23, 23), the return flow channel (25) is opened.

Battery powered electric motor-driven fire pump system for maintaining water pressure in a fire sprinkler network. The fire pump system includes: a fire pump controller including a fire pump controller logic, a battery charger and a plurality of starting contactors; a battery pack connected to the battery charger and to the plurality of starting contactors, the battery pack rechargeable by the battery charger; an electric motor powered by the battery pack through the plurality of starting contactors; and a fire pump drivable by the electric motor. In use, when the fire pump controller detects a drop in water pressure in the fire sprinkler network, the fire pump controller activates the electric motor to drive the fire pump to restore water pressure in the fire sprinkler network.

A pneumatic system operation control device for variable control of the rotation speed of an electric motor for driving an air-compressor such that constantly supplied pressure to a terminal device is achieved in accordance with a discharge pressure measurement value of the air-compressor and a supply pressure measurement value to the terminal device. The control device: stores the discharge pressure measurement value and the supply pressure measurement value; and, upon receiving input of an air pipe network model composed of data for calculating a flow of air in an air pipe network, calculates a flow rate of air supplied to the terminal device and an update value of a control setting value, and updates the control setting value to be used for variable control on the basis of the update value.

A pump volume control apparatus includes: a tilting piston; a pump volume switching valve configured to adjust a tilt driving pressure by a movement of a spool; a flow rate control spring configured to bias the spool in accordance with a tilt angle; a horsepower control piston configured to move in accordance with a pump discharge pressure; and a horsepower control spring configured to bias the horsepower control piston in accordance with the tilt angle. The tilt driving pressure is adjusted by means of the movement of the spool in accordance with a force acting on the spool in response to a flow rate controlling signal pressure in a flow rate controlled state, and is adjusted by means of the movement of the spool in accordance with a force acting on the horsepower control piston in response to the pump discharge pressure in a horsepower controlled state.

A portable hydraulic power unit includes a frame, a fluid tank supported by the frame, and a manifold supported by the frame. The fluid tank is configured to store a supply of hydraulic fluid for powering a hydraulically-driven tool. A reciprocating pump is mounted on the exterior of the fluid tank and on the exterior of the manifold. The reciprocating pump is secured to the fluid tank and the manifold with fasteners extending through a cylinder body of the reciprocating pump.