A displacement pump is configured to allow for assembly while properly maintaining side clearances. The displacement pump (100, 101, 102, 103, 104, 105) for sucking and discharging a fluid such as gasoline vapor by changing pressure in a space constituted by an outer peripheral surface of a rotor (1) and an inner wall surface of a casing (2), includes a side clearance adjusting member (4), rotating with respect to the pump main body (6), for moving a shaft (3) integrally formed with the rotor (1) in an axial direction of the shaft (3).

A compressor may include first and second compression members, first and second bearing assemblies, a sensor, and processing circuitry. The second compression member cooperates with the first compression member to define a compression pocket. The first and second bearing assemblies rotatably support the first and second compression members, respectively. The first bearing assembly may include a bearing rotor and a bearing stator. The bearing stator may surround the bearing rotor and may include poles each having a winding. The sensor may measure a radial position of the bearing rotor relative to the bearing stator. The processing circuitry may be in communication with the sensor and may control electrical current supplied to the windings based on the radial position measured by the sensor to adjust the radial position of the bearing rotor relative to the bearing stator.

The present invention provides a gear pump having one or more gears with bearing shafts supported by respective pressure-loaded gear pump bearing blocks. Each pressure-loaded bearing block has: a bore adapted to receive the bearing shaft of a gear of the pump; a thrust face at one end adapted to slidingly engage with a side surface of the gear, and an opposing rear face at the other end, the pump being adapted such that, in use, pressurised fluid is supplied to the rear face to provide a hydraulic load urging the thrust face of the bearing block towards the side surface of the gear; and a seal carried by the rear face, the seal, in use, partitioning higher fluid pressure and lower fluid pressure portions of the rear face. The gear pump further has a pressure regulating valve arranged such that, in use, the fluid pressure difference between the higher and lower fluid pressure portions of the rear face of the bearing block is adjustable by the valve to vary said hydraulic load.

A compressor includes a housing defining a working chamber. The housing further includes a bore and an endplate disposed toward a discharge end. The compressor further includes a rotor having helical threads, the rotor being configured to be housed in the bore, a rotor clearance, a controllable bearing supporting the rotor, and a controller configured to control the controllable bearing such that the controllable bearing moves the rotor in a manner to reduce and/or enlarge the rotor clearance.

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

A method for determining or monitoring the effective delivery flow of an eccentric screw pump that has a rotor rotating eccentrically in a stator at a pump frequency. The effective delivery flow is determined from the difference between an ideal delivery flow and a backflow, which backflow is dependent on at least one gap in the sealing line between rotor and stator. An operating parameter of the pump representing the gap is measured which pulses periodically with the pump frequency, the pulsation amplitude of which is dependent on the state of wear of the rotor and/or of the stator and is related to a tilting of the rotor in the stator. The backflow is calculated repeatedly using a mathematical model in dependence on the measured values for the operating parameter and on predetermined characteristic values of the pump and/or of the medium to be delivered.