A pump device includes a rotating body, a pump housing including a suction port and a discharge port, and a relief valve. In the pump device, a fluid is sucked from the suction port and discharged from the discharge port by rotation of the rotating body. The relief valve includes a valve body and a biasing member. The discharge port includes an one end in a direction in which the discharge port extends. The one end is shallower than a middle portion of the discharge port. The pump housing includes a relief flow path through which the fluid flows when the relief valve opens. The relief flow path is provided so as to be open to a groove bottom surface of the one end of the discharge port.

A valve arrangement to allow a fluid flow in a first direction and block it in a second direction opposite the first direction. The valve arrangement includes: a fluid channel, a valve seat and a closing body arranged in the fluid channel. The closing body prevents fluid flow in the second direction when resting against the valve seat and allows fluid flow in the first direction when the closing body is lifted off the valve seat; a closing body holder in the fluid channel configured to restrict movement of the closing body in the first direction when the closing body is lifted off the valve seat. The closing body holder held on an inner circumferential wall of the fluid channel in a frictional fit and/or movable in the first direction in a position in which the closing body holder is held on an inner circumferential wall of the fluid channel.

The present invention provides a quick startup device for a centrifugal pump. The device includes an upper self-priming chamber, a lower self-priming chamber, and an inlet pipe sequentially arranged from top to bottom. The upper self-priming chamber and the lower self-priming chamber are integrally mounted on the inlet pipe. A main shaft and a hexagonal partition member rotatably mounted on the main shaft are arranged on an axis of the upper self-priming chamber. A blade tip of each partition plate is closely attached to an inner wall surface of the upper self-priming chamber. Three identical accommodation grooves are provided on an inner side of the upper self-priming chamber. A spring and a separation baffle are arranged in each accommodation groove, an exhaust hole is provided on one side of each accommodation groove, and an air intake pipe is provided on the other side of each accommodation groove.

A liquid pump, in particular for providing a supply to a transmission or to a clutch in the drive train of a motor vehicle, includes a drive motor, a pump module which can be operated in two opposing directions of rotation, and at least one inlet and multiple outlets, each of which has at least one corresponding check valve. The pump has a valve plate corresponding to the pump module in which, for each check valve, a valve seat and a receptacle for a valve element interacting with the valve seat are provided.

A fluid pump includes a housing; an inlet passage; an outlet conduit; a pumping element within the housing; and a check valve assembly. The check valve assembly includes a valve stem within the outlet conduit such that a flow path is created radially between the outlet conduit and the valve stem, the valve stem moving along a check valve assembly axis between a closed position and an open position. The flow path includes a first restriction which increases velocity of fluid passing through the flow path; a first expansion, downstream of the first restriction, which decreases velocity of fluid passing through the flow path; a second restriction, downstream of the first expansion, which increases velocity of fluid passing through the flow path; and a second expansion, downstream of the second restriction, which decreases velocity of fluid passing through the flow path.

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 fluid pump includes a housing; an inlet passage; an outlet conduit; a pumping element within the housing; and a check valve assembly. The check valve assembly includes a valve stem within the outlet conduit such that a flow path is created radially between the outlet conduit and the valve stem, the valve stem moving along a check valve assembly axis between a closed position and an open position. The flow path includes a first restriction which increases velocity of fluid passing through the flow path; a first expansion, downstream of the first restriction, which decreases velocity of fluid passing through the flow path; a second restriction, downstream of the first expansion, which increases velocity of fluid passing through the flow path; and a second expansion, downstream of the second restriction, which decreases velocity of fluid passing through the flow path.

A device is provided for pumping fluid from a wellbore up to surface. The device includes a stator unit, a rotor unit run within the stator unit on a rod string, the rotor unit and the stator unit engaging with one another to form an annular space therebetween for passage of fluid. An upstream check valve on the rod string uphole of the rotor unit is moveable from an open position in which fluid is passable through the annular space, and a closed position in which fluid passage through the annular space is prevented. A hollow rod section extends through the rod string in fluid communication with the annular space both downstream and upstream of the upstream check valve, for entry of fluid into a downhole end of the hollow rod section, passage of fluid upstream therefrom and exit of fluids from an uphole end of the hollow rod section, back into the annular space. A method is further provided for pumping fluid from a wellbore after shutdown.

The present invention provides a quick startup device for a centrifugal pump. The device includes an upper self-priming chamber, a lower self-priming chamber, and an inlet pipe sequentially arranged from top to bottom. The upper self-priming chamber and the lower self-priming chamber are integrally mounted on the inlet pipe. A main shaft and a hexagonal partition member rotatably mounted on the main shaft are arranged on an axis of the upper self-priming chamber. A blade tip of each partition plate is closely attached to an inner wall surface of the upper self-priming chamber. Three identical accommodation grooves are provided on an inner side of the upper self-priming chamber. A spring and a separation baffle are arranged in each accommodation groove, an exhaust hole is provided on one side of each accommodation groove, and an air intake pipe is provided on the other side of each accommodation groove.

An in-wheel motor vehicle drive device includes an electric motor driving a drive gear, and the drive gear provided with a gear portion configured to receive drive force of the drive gear and a first wall surface extending along a direction orthogonal to an extending direction of a rotation center axis of the gear portion, the first wall surface for forming a pump chamber. The in-wheel motor vehicle drive device further includes a hub configured to transmit the drive force to the wheel, and an oil pump driven by the electric motor. The oil pump includes an oil pump cover including a second wall surface facing the first wall surface of the pump chamber, and a pump rotator arranged at a space between the first wall surface of the driven gear and the second wall surface of the oil pump cover, the pump rotator integrally rotating with the driven gear.