A method for pumping a liquid-gas mixture into a subsurface well includes introducing gas into a liquid at a first pressure to generate a mixture. The mixture is pumped through a first positive displacement pump to a second pressure greater than the first pressure. The mixture at the second pressure is pumped through at least a second positive displacement pump to a third pressure greater than the second pressure. The mixture is moved into the subsurface well at at least the third pressure.

An example assembly includes a main housing having an internal chamber therein; an electric motor disposed in the internal chamber of the main housing and comprising (i) a stator that is fixedly-positioned in the internal chamber of the main housing, and (ii) a motor rotor positioned within the stator and rotatable relative to the stator; a hydraulic pump positioned in the main housing, at least partially within the motor rotor of the electric motor, wherein the hydraulic pump is configured to receive fluid from an inlet port and provide fluid flow to an outlet port, wherein the hydraulic pump comprises a pump drive shaft rotatably-coupled to the motor rotor of the electric motor; and a plurality of cooling fluid channels formed in the main housing and configured to allow fluid to circulate through the main housing to cool the main housing.

A transfer case pump includes an oil pump, a cover assembly, and a torque transfer mechanism. The oil pump has a pump shaft, and is configured to pressurize a lubricant in response to a rotation of the pump shaft. The pump shaft rotates around a pump axis. The pump axis is parallel to a rear axis of a rear shaft. The pump axis is offset from the rear axis. The cover assembly has a channel configured to transfer the lubricant from the oil pump to the rear shaft. The cover assembly extends around the rear shaft and around the pump shaft. The torque transfer mechanism is configured to transfer a torque from the rear shaft to the pump shaft.

A transfer case pump includes an oil pump, a cover assembly, and a torque transfer mechanism. The oil pump has a pump shaft, and is configured to pressurize a lubricant in response to a rotation of the pump shaft. The pump shaft rotates around a pump axis. The pump axis is parallel to a rear axis of a rear shaft. The pump axis is offset from the rear axis. The cover assembly has a channel configured to transfer the lubricant from the oil pump to the rear shaft. The cover assembly extends around the rear shaft and around the pump shaft. The torque transfer mechanism is configured to transfer a torque from the rear shaft to the pump shaft.

A dual vane pump system includes first and second vane pumps having first and second rotors with a plurality of vanes moving radially inwardly and outwardly of the first and second rotors, and into contact with an inner surface of the first and second outer liners. A first pre-pressurization passage connects a first pump inlet in the first pump that is at discharge pressure to a second pump outlet in the second pump which is upstream of the second discharge opening. There is a coupling connecting the first and second rotors for rotation together. The pre-pressurization passage extending through the bearing.

A diaphragm pump having a crankshaft that is rotatable about a rotational axis and coupled to a piston. The piston is reciprocally displaceable within a piston cylinder along an axis of motion between suction and discharge strokes. A diaphragm housing coupled to the piston cylinder at least partially defines a pumping chamber through which fluid is pumped as the piston reciprocates. The axis of motion, which intersects a connection between the piston and the connecting rod, may not intersect the rotational axis of the crankshaft such that, relative to an arrangement in which the axis of motion does intersect the rotational axis, a peak magnitude of piston side load forces during the discharge stroke is reduced and a peak magnitude of piston side load forces during the suction stroke is increased so as to attain an improved balance between the peak magnitudes of piston side load forces of the discharge and suction strokes.

One example of a gerotor pump includes an inner rotor comprising multiple teeth, the inner rotor configured to rotate about a first longitudinal gerotor pump axis. The gerotor pump also includes a hollow outer rotor including an outer surface and an inner surface having substantially identical contours, the inner surface configured to engage with the multiple teeth and to rotate about a second longitudinal gerotor pump axis. The pump includes a pump housing within which the inner rotor and the outer rotor are disposed, wherein the outer surface of the outer rotor defines gaps between the pump housing and the outer rotor.

A compressor includes: a driving unit including a stator, a rotor, and a rotary shaft provided in the rotor, having an oil guide path formed at an inner side in a radius direction; a compression unit coupled to the rotary shaft, having a cylinder and a piston reciprocating in the cylinder by a driving force of the driving unit; and an oil supply unit coupled to a lower end of the rotary shaft, supplying oil toward the compression unit. The oil supply unit includes a rotary portion for supplying oil toward the oil guide path while being rotated together with the rotary shaft and a fixed portion having an inner space partitioned to accommodate at least a portion of the rotary portion, and the oil guide path is formed to pass through the rotary shaft along a length direction.

A diaphragm pump having a crankshaft that is rotatable about a rotational axis and coupled to a piston. The piston is reciprocally displaceable within a piston cylinder along an axis of motion between suction and discharge strokes. A diaphragm housing coupled to the piston cylinder at least partially defines a pumping chamber through which fluid is pumped as the piston reciprocates. The axis of motion, which intersects a connection between the piston and the connecting rod, may not intersect the rotational axis of the crankshaft such that, relative to an arrangement in which the axis of motion does intersect the rotational axis, a peak magnitude of piston side load forces during the discharge stroke is reduced and a peak magnitude of piston side load forces during the suction stroke is increased so as to attain an improved balance between the peak magnitudes of piston side load forces of the discharge and suction strokes.

A system including an engine block and a crankshaft able to rotate around axis A, and a compressor with a rotor, the rotor mounted coaxially to the crankshaft such that the crankshaft drives the rotor. The system can be part of an engine for a vehicle, and the compressor can be an air compressor which is able to supply compressed air for engine systems.