A vacuum pump having a housing which limits a working space and having a rotor, rotatably mounted in the housing about a rotor axis, the rotor guides a vane being movably mounted in the radial direction, the vane has a transverse extent, and the vane divides the working space into a suction side having a suction inlet and a pressure side having a pressure outlet, the housing has at least one oil outlet, the oil outlet is closed by a relief valve, the relief valve assumes an open position, when a limit pressure lying above a nominal pressure is exceeded in the working space, and the transverse extent of the vane is large enough that when the vane passes the oil outlet, the oil outlet is closed by the vane, so that there is no fluid connection between the suction side and the pressure side over the oil outlet.

A driving power transmission device includes a fluid pressure type clutch device that transmits driving power between two shaft members, and a pump that supplies a fluid to the clutch device. The pump includes a pump that makes a pressure of sucked fluid high; a first flow passage through which the fluid according to a pressure discharged from the pump is supplied to the clutch device during a driving of the pump; a second flow passage through which the fluid discharged from the pump is held during a stop of the pump and a pressing force is applied to the clutch device by the fluid to be held; and a switching valve that is switchable between a normal mode where a discharge port of the pump communicates with the first flow passage and a locking mode where the discharge port of the pump communicates with the second flow passage.

An oscillating pump system includes a pump operable to circulate a fluid. The pump has a first port stage including an inlet port and an outlet port and a second port stage including a first oscillating port and a second oscillating port. An oscillator disk is disposed between the first port stage and the second port stage. The oscillator disk is rotatable relative to the inlet port, the outlet port, the first oscillating port and the second oscillating port. During rotation, the oscillator disk alternatingly routes the fluid to the inlet port from the first and second oscillating ports and alternatingly routes the fluid from the outlet port to the first and second oscillating ports, thereby generating oscillating fluid flow.

The present invention discloses a hydraulic style motor having a first power input housing containing a first plurality of rotary or centrifugally driven pumps and associated valves, such that the pumps are driven in a determined stacked fashion by a powered input (or drive) shaft. A second power output housing contains at least one second rotary driven pump and associated valve, the second pumps rotatably engaging a second output (driven) shaft. A pressure resistant fluid line interconnects a manifold associated with the first housing with another manifold associated with the second housing so that the pressurized fluid generated by rotation of the input pumps in the input housing is communicated to the output housing to drive the output pumps to rotate the output (driven) shaft. A return line communicates with the output housing manifold, via each of the individual pump and valve subassemblies, for redirecting flow back to an input feed to the input housing.

The invention provides a pump comprising a pump inlet, a pump outlet, at least two threaded rotors and a pressure controlled valve, the pressure controlled valve being capable of controlling re-circulation of fluid from the pump outlet to the pump inlet. The pressure controlled valve can be a control valve. The invention also provides a multiple stage pump assembly comprising at least two pumps arranged in series, wherein at least one of the pumps is the aforementioned pump.

An injector generator for use in geomechanical pumped storage systems includes a power end and a fluid end. The fluid end has one or more fluid chambers each having a fluid inlet and outlet that are controlled by rotary valves. The fluid end can function as a pump or as a motor driven by fluid pressure from the geomechanical storage formation.

A scroll compressor includes a movable scroll, a fixed scroll having a suction passage, a suction pipe, and a suction check valve to open and close an open end of the suction pipe. The suction check valve includes a valve body, a valve seat, and a compression spring to bias the valve body toward the open end of the suction pipe. The valve body includes a first bottom portion, and a first circumferential wall extending toward the valve seat along a peripheral portion of the first bottom portion. The valve seat includes a second bottom portion, and a second circumferential wall extending toward the valve body along a peripheral portion of the second bottom portion. One of the first and second circumferential walls has an outside diameter smaller than an inside diameter of an open end of the other one of the first and second circumferential walls.

Methods and apparatus pertaining to positive displacement pumps, and further to hydraulic actuation systems. In some embodiments the pumps are gear pumps with bi-directional operation. In some embodiments the actuation system includes a motor-driven, reversible operation gear pump providing fluid under pressure to a rod and cylinder.

A pump may generally include a frame including a reservoir. The reservoir stores a hydraulic fluid. The pump may also include a motor assembly supported by the frame and a pump assembly operably driven by the motor assembly. The pump assembly is in fluid communication with the reservoir and configured to dispense the hydraulic fluid out of the frame. The pump assembly includes a first piston and a second piston, wherein the first piston dispenses hydraulic fluid out of the frame between a first pressure and a second pressure greater than the first pressure, and the second piston dispenses hydraulic fluid out of the frame between the first pressure and a third pressure, the third pressure being greater than the second pressure.

A driving power transmission device includes a fluid pressure type clutch device that transmits driving power between two shaft members, and a pump that supplies a fluid to the clutch device. The pump includes a pump that makes a pressure of sucked fluid high; a first flow passage through which the fluid according to a pressure discharged from the pump is supplied to the clutch device during a driving of the pump; a second flow passage through which the fluid discharged from the pump is held during a stop of the pump and a pressing force is applied to the clutch device by the fluid to be held; and a switching valve that is switchable between a normal mode where a discharge port of the pump communicates with the first flow passage and a locking mode where the discharge port of the pump communicates with the second flow passage.