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 fuel system for a turbomachine includes a fuel tank and a first fuel line in fluid communication with the fuel tank and one or more fuel injectors. The first fuel line includes a main fuel pump disposed on the first fuel line, and an electric metering system disposed on the first fuel line downstream of the main fuel pump configured for starting the turbomachine and metering fuel to the fuel injectors.

A metering distribution assembly and a coating system. The metering distribution assembly includes a volumetric cavity pump that comprises a flow passage plate having flow passages, a nozzle plate with a flow passage, a gear fixing plate attached between the flow passage plate and the nozzle plate, and a gear set located in an aperture of the fixing plate. The gear set has a fluid inlet and a fluid outlet on a side of the gear set opposite to the fluid inlet. The fluid inlet is in fluid communication with the flow passages of the flow passage plate, and the fluid outlet is in fluid communication with the flow passage of the nozzle plate. A part of the flow passages of the flow passage plate, which is in direct fluid communication with the fluid inlet, extends in a direction parallel to a rotation axis of the gear set.

A gerotor device for a pump apparatus is disclosed. The gerotor device includes at least two gerotor stages that respectively include an inner rotor rotating during operation about an inner axis with teeth projecting radially outside, and an outer rotor rotating during operation about an outer axis radially offset relative to the inner axis with radially inner open tooth gaps, in which the teeth of the inner rotor engage. A rotor body rotating during operation about a rotor axis includes radially open tooth gaps of a first gerotor stage of the at least two gerotor stages and teeth projecting radially outside of a second gerotor stage of the at least two gerotor stages. The tooth gaps of the at least two gerotor stages are fluidically sealed at least one of against one another and relative to a surrounding area.

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.

Sealing in rotary positive displacement machines based on trochoidal geometry that comprise a helical rotor that undergoes planetary motion within a helical stator is described. Seals can be mounted on the rotor, the stator, or both. The rotor can have a hypotrochoidal cross-section, with the corresponding stator cavity profile being the outer envelope of the rotor as it undergoes planetary motion, or the stator cavity can have an epitrochoidal cross-section with the corresponding rotor profile being the inner envelope of the trochoid as it undergoes planetary motion. In some embodiments, the geometry is offset in a manner that provides advantages with respect to sealing in the rotary machine. In multi-stage embodiments, the rotor-stator geometry remains substantially constant or varies along the axis of the rotary machine.

A rotor for a mud motor includes a core having a first outer shape, and a shell positioned around the core, the shell having a second outer shape that is different from the first outer shape, the second outer shape defining one or more lobes and one or more cavities that are configured to engage a bore of a stator during rotation of the rotor relative to the stator. A thickness of the shell varies as proceeding around the core, from a non-zero minimum thickness to a maximum thickness.

Rotary positive displacement machines based on trochoidal geometry that includes a helical rotor that undergoes planetary motion relative to a helical stator are described. The rotor can have a hypotrochoidal-based cross-sectional shape, with the corresponding stator cavity cross-sectional shape being the outer envelope of the rotor cross-sectional shape as it undergoes planetary motion, or the stator cavity can have an epitrochoidal-based cross-sectional shape with the corresponding rotor cross-sectional shape being the inner envelope of the stator cross-sectional shape as it undergoes planetary motion. Such machines can be configured so that the stator axis is spaced from the rotor axis, the rotor is configured to spin about its axis and the stator is configured to spin about its axis, and/or the rotor and the stator are held at a fixed eccentricity so that the rotor undergoes planetary motion relative to the stator, but does not orbit.

A fuel pump assembly for a gas turbine engine includes a shaft for transmitting motion, a gear connected to and coaxial with the shaft with the gear having a first wear surface, a first bearing coaxial with the shaft with the first bearing being configured to support the gear and having a second wear surface positioned to interact with the first wear surface, and a plurality of indents. The indents are distributed in the first wear surface or the second wear surface and at least two of the plurality of indents are partially aligned in a radial direction.

An oil pump is configured to include a rotor, a drive shaft that drives the rotor to rotate, a rotor chamber in which the rotor is contained, an inlet port and an outlet port each provided in the vicinity of the rotor chamber, and a pump cover. The pump cover is made of a resin. On a portion of an outer surface side of the pump cover corresponding to an inner portion, in which oil circulates, of the pump cover, a rib that has an erecting wall shape is provided.