A gear pump includes a pair of gears having meshed teeth. One of the gears is configured for connection to a source of drive. The gears are received within a housing. The housing has an inlet port configured for connection to a source of fluid and an outlet port. Each of the gears have a shaft rotating within the housing on a bearing on each axial side of each gear. At least one of the bearings associated with each of the pair of gears has a plurality of springs received in recesses to bias the said at least one bearing against an end face of a respective one of the pair of gears. A retention plate holds each of the plurality springs. A method of assembly is also disclosed.

An eccentric screw pump for delivering solid-laden liquids includes a rotor and a stator within which the rotor is rotatably arranged. The rotor and stator are arranged and designed with respect to one another in such a way that at least one chamber is formed, which serves to transport the liquid. The eccentric screw pump has a drive motor for rotating the rotor, a control device for controlling the drive motor at least in a working state, in which the rotor is rotated, and an idle state, in which the rotor does not rotate, and an engagement unit, which is designed to set an engagement between the rotor and stator to an idle engagement in the idle state and to a working engagement in the working state. The idle engagement is less than the working engagement. A method for operating the eccentric screw pump is also disclosed.

An eccentric screw pump for delivering solid-laden liquids includes a rotor and a stator within which the rotor is rotatably arranged. The rotor and stator are arranged and designed with respect to one another in such a way that at least one chamber is formed, which serves to transport the liquid. The eccentric screw pump has a drive motor for rotating the rotor, a control device for controlling the drive motor at least in a working state, in which the rotor is rotated, and an idle state, in which the rotor does not rotate, and an engagement unit, which is designed to set an engagement between the rotor and stator to an idle engagement in the idle state and to a working engagement in the working state. The idle engagement is less than the working engagement. A method for operating the eccentric screw pump is also disclosed.

An operational control device is disclosed for a positive-displacement pump having a motor, means for actuating the motor, state sensor means for detecting an actual operating parameter (e.g., pressure) of the pump, and operating mode means for controlling an operating mode of the pump. A first actuating mode of the operating mode means is set by the actuating means below a first operating-parameter threshold value (P1). This mode brings about a constantly rising pump pressure in the direction of an operating-parameter setpoint value (Pset) in a variable manner, which is dependent on a detected change in the operating parameter over a predefined time interval. A second actuating mode is set as normal operation to the operating-parameter setpoint value by the actuating means above the first operating-parameter threshold value. P1 is fixed or is calculated as a fraction of the operating-parameter setpoint value and/or a pump parameter correlated therewith.

An operational control device is disclosed for a positive-displacement pump having a motor, means for actuating the motor, state sensor means for detecting an actual operating parameter (e.g., pressure) of the pump, and operating mode means for controlling an operating mode of the pump. A first actuating mode of the operating mode means is set by the actuating means below a first operating-parameter threshold value (P1). This mode brings about a constantly rising pump pressure in the direction of an operating-parameter setpoint value (Pset) in a variable manner, which is dependent on a detected change in the operating parameter over a predefined time interval. A second actuating mode is set as normal operation to the operating-parameter setpoint value by the actuating means above the first operating-parameter threshold value. P1 is fixed or is calculated as a fraction of the operating-parameter setpoint value and/or a pump parameter correlated therewith.

Hydraulic devices are shown and described that can include a rotor, vanes and a ring. The rotor can be disposed for rotation about an axis. The plurality of vanes can each include a vane step. Each of the plurality of vanes can be moveable relative to the rotor between a retracted position and an extended position where the plurality of vanes work a hydraulic fluid introduced adjacent the rotor. A roller can be mounted to a tip of each of the plurality of vanes. The ring can be disposed at least partially around the rotor. The rotor can include one or more passages for ingress or egress of a hydraulic fluid to or from a region adjacent the vane step and defined by at least the rotor and the vane step.

The application relates to a positive displacement pump shaft bearing assembly that comprises a shaft having a shaft lodging and a shaft rotational axis. The assembly further comprises a housing having a housing lodging and one rolling element that is located between said lodgings. The rolling element comprises a rolling element centre point that coincides with the shaft rotational axis.

A pump having a stroke ring which has an axial recess, a rotor which is received in the axial recess so as to be rotatable relative to the stroke ring, wherein the rotor has radial recesses in which delivery elements are displaceable received as viewed in a radial direction, a side plate which closes off the axial recess on a first side, a pressure plate which closes off the axial recess on a second side, wherein the pressure plate has at least one opening, wherein a pressure region of the pump is fluidically connected to external surroundings of the pressure plate through the at least one opening, and wherein at least one fluid path is provided from the pressure region of the pup into an under-vane region of the delivery elements, and a cold-start plate which is preloaded against the pressure plate by means of a spring element such that, at least when the pump is at a stand-still, the cold-start plate closes the at least one opening in the pressure plate to the external surroundings of the pressure plate. The pump is characterized in that the spring element is supported on the pressure plate so as to introduce preload forces into the cold-start plate, and in that the spring element is fastened to the pressure plate.

A pump having a stroke ring which has an axial recess, a rotor which is received in the axial recess so as to be rotatable relative to the stroke ring, wherein the rotor has radial recesses in which delivery elements are displaceable received as viewed in a radial direction, a side plate which closes off the axial recess on a first side, a pressure plate which closes off the axial recess on a second side, wherein the pressure plate has at least one opening, wherein a pressure region of the pump is fluidically connected to external surroundings of the pressure plate through the at least one opening, and wherein at least one fluid path is provided from the pressure region of the pup into an under-vane region of the delivery elements, and a cold-start plate which is preloaded against the pressure plate by means of a spring element such that, at least when the pump is at a stand-still, the cold-start plate closes the at least one opening in the pressure plate to the external surroundings of the pressure plate. The pump is characterized in that the spring element is supported on the pressure plate so as to introduce preload forces into the cold-start plate, and in that the spring element is fastened to the pressure plate.

A progressive cavity pump (PCP) system includes a PCP with a rotor rotatably disposed in a stator, a permanent magnet motor, sucker rod(s), and a control system. The rotor is coupled to one of the sucker rods via a high-torque connection that allows for counter clockwise rotation without loosening the connection between the rotor and sucker rod. The control system operates the system in a production mode by rotating the rotor clockwise. Upon manual input by a user, or automatic triggering when protections settings of the control system call for a shutdown or cleanout or when the control system senses an imminent pump shutdown, the control system operates the system in a reverse mode by rotating the rotor counterclockwise. The reverse mode pumps fluids and suspended solid particles down into the well prior to pump shutdown to inhibit the solids from clogging the pump or preventing the pump from restarting.