A pump having at least two fluid drivers and a method of delivering fluid from an inlet of the pump to an outlet of the pump using the at least two fluid drivers. Each of the fluid drives includes a prime mover and a fluid displacement member. The prime mover drives the fluid displacement member to transfer fluid. The fluid drivers are independently operated. However, the fluid drivers are operated such that contact between the fluid drivers is synchronized. That is, operation of the fluid drivers is synchronized such that the fluid displacement member in each fluid driver makes contact with another fluid displacement member. The contact can include at least one contact point, contact line, or contact area.

An electric pump actuator for a continuously variable transmission includes a gear wheel pump, a first electric motor, a second electric motor, and an electric control unit. The gear wheel pump has a first gear wheel and a second gear wheel meshing with the first gear wheel. The first electric motor is for actuating the first gear wheel, and the second electric motor is for actuating the second gear wheel independent of the first gear wheel. The electronic control unit is arranged to control the first electric motor to transmit a first torque to the first gear wheel, and control the second electric motor to transmit a second torque to the second gear wheel that is set against the first torque in at least one rotation angle range.

A rotary lobe pump having a pump housing with a pump room, an inlet opening and an outlet opening, a first multi-lobe rotary piston, which is arranged in the pump room and is rotatably mounted about a first axis of rotation, a second multi-lobe rotary piston, which is arranged in the pump room and is rotatably mounted about a second axis of rotation spaced apart from the first axis of rotation and meshingly engages in the first rotary piston, wherein the first and second rotary pistons are drivable in opposite directions and are designed to generate a flow of a conveyed medium from the inlet opening through the pump room to the outlet opening by counter-rotation about the first and second axis of rotation, respectively, and a drive device, which is mechanically coupled to the rotary pistons for driving the rotary pistons.

An apparatus includes a torque adjustment circuit to receive a torque setpoint and a torque feedback signal corresponding to a differential torque between a pair of meshing gear teeth of a first gear and a second gear. The torque adjustment circuit is further configured to output a torque adjustment signal corresponding to a difference between the torque setpoint and the torque feedback signal. The apparatus also includes a motion control circuit to provide a first speed demand signal to a first motor that drives the first gear and a second demand signal to a second motor that drives the second gear, and dynamically synchronize torque between the pair of meshing gear teeth such that the differential torque between the pair of meshing gear teeth is within a predetermined range by adjusting at least one of the first speed demand signal or the second speed demand signal.

An oil-injected multi-stage compressor system that comprises at least a low-pressure stage compressor element (2) with an inlet (4a) and an outlet (5a) and a high-pressure stage compressor element (3) with an inlet (4b) and an outlet (5b), whereby the outlet (5a) of the low-pressure stage compressor element (2) is connected to the inlet (4b) of the high-pressure stage compressor element (3) through a pipeline (6), characterized in that the compressor elements (2, 3) are provided with their own drive in the form of an electric motor (2a, 3a), whereby the compressor elements (2, 3) are connected to the electric motor (2a, 3a) either directly or through a gearbox and that an intercooler (9) is provided in the aforementioned pipeline (6) between the low-pressure stage compressor element (2) and the high-pressure stage compressor element (3).

A pump having at least two fluid drivers and a method of delivering fluid from an inlet of the pump to an outlet of the pump using the at least two fluid drivers. Each of the fluid drives includes a prime mover and a fluid displacement member. The prime mover drives the fluid displacement member to transfer fluid. The fluid drivers are independently operated. However, the fluid drivers are operated such that contact between the fluid drivers is synchronized. That is, operation of the fluid drivers is synchronized such that the fluid displacement member in each fluid driver makes contact with another fluid displacement member. The contact can include at least one contact point, contact line, or contact area.

The invention relates to a method for controlling a rotary screw compressor, having at least a first and a second air-end, wherein both air-ends are driven separately from one another and speed controlled. According to the invention, the following steps are carried out: detection of a volume flow taken at the outlet of the second air-end; adjustment of the rotational speed of both air-ends, when the removed volume flow fluctuates in a range between a maximum value and a minimum value; opening of a pressure-relief valve, if the volume flow falls below the minimum value; and reduction of the rotational speed of at least the first air-end to a predetermined idling speed (V1.sub.L) to reduce the volumetric flow delivered by the first to the second air-end.

An electric motor, in particular for a vacuum pump, with two magnetically coupled shafts. A correction force can be set on each shaft by means of adjusting magnet devices, whereby negative effects due to errors in the magnetic coupling can be compensated.

A pump having at least two fluid drivers and a method of delivering fluid from an inlet of the pump to an outlet of the pump using the at least two fluid drivers. Each of the fluid drives includes a prime mover and a fluid displacement member. The prime mover drives the fluid displacement member to transfer fluid. The fluid drivers are independently operated. However, the fluid drivers are operated such that contact between the fluid drivers is synchronized. That is, operation of the fluid drivers is synchronized such that the fluid displacement member in each fluid driver makes contact with another fluid displacement member. The contact can include at least one contact point, contact line, or contact area.

A multi-stage dry Roots vacuum pump, including a pump body, multi-stage Roots working units and a plurality of drive components. The pump body is provided with a plurality of independent working chambers, and airflow channels communicating the various working chambers; the airflow channels are communicated with outside; the Roots working units of each stage include driving Roots rotors and driven Roots rotors; the driving Roots rotors and driven Roots rotors are positioned in the working chambers; and the various drive components are respectively used for driving the driving Roots rotors and driven Roots rotors positioned in the various working chambers to rotate towards opposite directions at the same rotating speed. The Roots working units of various stages may be randomly distributed at various positions of the pump body on premise of ensuring that the airflow channels can communicate the working chambers of each stage.