Cylindrical symmetric volumetric machine (1), which machine (1) includes two cooperating rotors (6a, 6b), namely an outer rotor (6a) which is rotatably mounted in the machine (1) and an inner rotor (6b) which is rotatably mounted in the outer rotor (6a), whereby the machine (1) is provided with an electric motor (15) with a motor rotor (16) and a motor stator (17) to drive the outer and inner rotor (6a, 6b), characterised in that the electric motor (15) is mounted around the outer rotor (6a), whereby the motor stator (17) is directly driving the outer rotor (6a), and whereby the electric motor (15) extends along only a part of the length (L) of the outer rotor (6a) and the inner rotor (6b), whereby the motor (15) is located at an end (9b) of the inner rotor (6b) with a smallest diameter (D).

A pump includes a housing, a drive shaft, a centrifugal pump portion having an impeller, and a gear pump portion having first and second gears. The impeller and one of the first and second gears are mounted to the drive shaft to drive the centrifugal pump portion and the gear pump portion at the same rotational speed. The gear pump can be a crescent internal gear (CIG) pump. The drive shaft can be rotated by a magnetic drive. The drive shaft can include a longitudinal bore in fluid communication with a cavity in the magnetic drive and with a discharge of the centrifugal pump portion to circulate working fluid through the magnetic drive to cool the drive. An impeller can be coupled to an inlet of the centrifugal pump portion.

A magnetically engaged pump includes a pump housing with a rotatable magnetic drive assembly, a cylindrical canister and a rotatable driven magnet assembly. This magnetic coupling is associated with a pump rotor and a laterally positioned gear wheel to define a gear pump. This magnetic coupling is alternatively associated with a pump rotor with an impeller to define a centrifugal pump. Either pump includes a stationary shaft to mount the driven magnet assembly and pump rotor. A rotatable carrier with bushings and thrust bushings coaxially supports the rotatable driven magnet assembly and pump rotor.

A magnetically engaged pump includes a pump housing with a rotatable magnetic drive assembly, a cylindrical canister and a rotatable driven magnet assembly. This magnetic coupling is associated with a pump rotor and a laterally positioned gear wheel to define a gear pump. This magnetic coupling is alternatively associated with a pump rotor with an impeller to define a centrifugal pump. Either pump includes a stationary shaft to mount the driven magnet assembly and pump rotor. A rotatable carrier with bushings and thrust bushings coaxially supports the rotatable driven magnet assembly and pump rotor.

A rotor assembly for a rotary fluid device that includes a first body at least partially exposed to a process fluid, a second body at least partially exposed to the process fluid, a connecting apparatus that includes at least one connector and at least one seal that connects the first body to the second body and seals the at least one connector from exposure to the process fluid.

A surface-driven fluid recovery system for recovery of hydrocarbons, having an uphole prime mover, typically an electric motor, and an uphole speed-reduction transmission to reduce speed of rotation supplied by the prime mover to a rod string to thereby reduce frictional and cyclic fatigue stresses imparted on the rod string. A downhole speed-increasing transmission is provided to increase rotational speed prior to supply of rotational energy to a downhole centrifugal or progressive cavity pump. A magnetic coupling is interposed between the prime mover and the speed reduction gearbox or between the speed reduction gearbox and the rod string, to provide damping of high transient rotational stresses between the prime mover and the rod string and/or provide a method for selectively coupling or partially coupling/decoupling the rod string to the prime mover.

A magnetically engaged pump includes a pump housing with a rotatable magnetic drive assembly, a cylindrical canister and a rotatable driven magnet assembly. This magnetic coupling is associated with a pump rotor and a laterally positioned gear wheel to define a gear pump. This magnetic coupling is alternatively associated with a pump rotor with an impeller to define a centrifugal pump. Either pump includes a stationary shaft to mount the driven magnet assembly and pump rotor. A rotatable carrier with bushings and thrust bushings coaxially supports the rotatable driven magnet assembly and pump rotor.

The disclosure provides a gear pump rotor assembly that includes a rotor body, a rotor head having a plurality of gear teeth and being connected to the rotor body, at least one connector extending between the rotor body and the rotor head, at least one radial deformation control member that extends into at least one gear tooth of the rotor head and reduces the radial deformation of the rotor head relative to the rotor body when a change in temperature causes radial deformation of the rotor body and rotor head.

The invention relates to a screw pump (1), in particular a double screw pump, s comprising a multiple-piece housing (2, 7, 15, 21) and at least two coupled rotors (3, 3a) which form chambers with in each case at least one thread-shaped profile (4, 4a) which is configured at least in regions with helical channels (5, 5a) and with dividing walls (6, 6a) which delimit the channels (5, 5a), wherein the rotors (3, 3a) perform an opposed rotor rotation, and the dividing walls (6, 6a) engage into one another in a gearwheel-like manner, a running housing part (7), wherein the running housing part (7) encloses the rotors (3, 3a) without contact, wherein the rotors (3, 3a) form, with the running housing part (7), at least one conveying chamber (8, 8a) for the fluid to be conveyed, wherein the conveying chamber (8, 8a) migrates axially along the rotor axis (10, 10a) and conveys the fluid from a suction chamber (11) into a pressure chamber (12), a suction-side connector element (13) which is connected fluidically to the suction chamber (11), and a pressure-side connector element (14) which is connected fluidically to the pressure chamber (12), wherein the suction-side connector element (13) and the pressure-side connector element (14) are arranged on a connector housing part (15) of the multiple-piece housing (2, 7, 15, 21), wherein the housing (2, 7, 15, 21) has a planar dividing plane (16) which runs parallel to the rotor axes (10, 10a) between the running housing part (7) and the connector housing part (15).

A magnetic coupling assembly includes a first balancing magnet positioned and surrounding drive magnets and, across a gap, a second balancing magnet and surrounding driven magnets. The drive magnets when rotated drive the driven magnets to rotate. The balancing magnets generate a repulsive force, which counterbalances an attractive force generated by the drive magnets and driven magnets. The assembly may be utilized in a pump for contactless coupling of a motor shaft to a pump shaft. The driven side of the assembly may be hermetically sealed, such as with a liquid crystal polymer boundary interposed in the gap.