An on-demand fluid transfer pump includes a power head removably connectable on top of a stem that is removably connectable to a fluid supply. The power head includes an electric pump and a flow control unit configured to automatically switch the electric pump on and off. The flow control unit includes a magnetic sensor and the stem includes a suction tube, a fluid chamber, a plunger chamber, and a magnetic plunger reciprocable within the plunger chamber in response to pressure changes in the fluid chamber. The magnetic plunger is biased to deactuate the magnetic sensor to switch on the electric pump to pressurize the fluid supply for delivery to the fluid dispenser. The magnetic plunger is pushed when pressure in the fluid chamber rises to thereby actuate the magnetic sensor to switch off the electric pump.

A method for controlling a permanent magnet (PM) synchronous motor in an ESP application is provided. A load angle of the PM motor is estimated. A voltage adjustment value is determined for the PM motor based at least on the estimated load angle of the PM motor. A voltage to be applied to the PM motor is determined based on the voltage adjustment value.

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.

A device is described for transmitting mechanical power that allows variable output-speed to input-speed ratios. Gear sets such as epicyclic gear sets have components that rotate about a common axis selectively at the same rotational speed and at different relative rotational speeds as determined by at least one of fluid flow and fluid pressure. One or more inlet ports and fluid passageways introduce a working fluid into one or more volume spaces between the components. The internal pressure and flow of the working fluid through the device is controlled to provide substantially infinite variability of the output-speed to input-speed ratios for applications where, for example, an engine provides the mechanical power for propelling a vehicle.

A device is described for transmitting mechanical power that allows variable output-speed to input-speed ratios. Gear sets such as epicyclic gear sets have components that rotate about a common axis selectively at the same rotational speed and at different relative rotational speeds as determined by at least one of fluid flow and fluid pressure. One or more inlet ports and fluid passageways introduce a working fluid into one or more volume spaces between the components. The internal pressure and flow of the working fluid through the device is controlled to provide substantially infinite variability of the output-speed to input-speed ratios for applications where, for example, an engine provides the mechanical power for propelling a vehicle.

A vane oil pump includes a rotor including a plurality of slits, a housing having an inner circumferential cam surface such that a first pump unit and a second pump unit taking in and discharging oil in accordance with rotation of the rotor are separately disposed in a rotational direction of the rotor, a plurality of vanes respectively fitted in the slits of the rotor, and a pressure adjusting device configured to adjust a second discharge pressure of the second pump unit to a lower pressure than a first discharge pressure of the first pump unit. A back pressure groove is disposed on the housing and is provided to supply back pressure oil to a bottom portion of each slit.

Machine provided with a machine element (2) and an oil pump (4) and a motor (3) to drive the machine element (2) and the oil pump (4), whereby the oil pump (4) is provided with a shaft (13) with a rotor (12), whereby the oil pump (4) is provided to pump oil from an oil reservoir (5) via an inlet channel (8) to nozzles that lead into the motor (3) and/or machine element (2) to lubricate and/or cool one or more bearings or other machine components, characterized in that in the inlet channel (8), near the oil pump (4) a dam (16) is provided that is higher than the height (A) of the central axis (18) of the shaft (13) of the oil pump (4) minus the smallest diameter (B) of the rotor (12) of the oil pump (4) divided by two.

Machine provided with a machine element (2) and an oil pump (4) and a motor (3) to drive the machine element (2) and the oil pump (4), whereby the oil pump (4) is provided with a shaft (13) with a rotor (12), whereby the oil pump (4) is provided to pump oil from an oil reservoir (5) via an inlet channel (8) to nozzles that lead into the motor (3) and/or machine element (2) to lubricate and/or cool one or more bearings or other machine components, characterized in that in the inlet channel (8), near the oil pump (4) a dam (16) is provided that is higher than the height (A) of the central axis (18) of the shaft (13) of the oil pump (4) minus the smallest diameter (B) of the rotor (12) of the oil pump (4) divided by two.

One or more techniques and/or systems are disclosed for providing for improved liquid fuel delivery, by helping to mitigate damage to pumps when operated in an undesired condition. A sensor detects the presence of a liquid fuel at the inlet to the pump during pump operation, and sends the signal to a controller. Based on the detection signal from the sensor, the controller can determine whether a desired amount of liquid is present at the inlet to the pump. If a desired amount of liquid is not identified at the inlet to the pump, the controller may interrupt the power provided by a power supply, which is supplying power to operate the pump, thereby interrupting operation of the pump.

One or more techniques and/or systems are disclosed for providing for improved liquid fuel delivery, by helping to mitigate damage to pumps when operated in an undesired condition. A sensor detects the presence of a liquid fuel at the inlet to the pump during pump operation, and sends the signal to a controller. Based on the detection signal from the sensor, the controller can determine whether a desired amount of liquid is present at the inlet to the pump. If a desired amount of liquid is not identified at the inlet to the pump, the controller may interrupt the power provided by a power supply, which is supplying power to operate the pump, thereby interrupting operation of the pump.