Linear electric motor for downhole use
Patent
·
OSTI ID:6264000
This patent describes a production tubing string: a tube of non-magnetic material substantially of the same internal diameter as the tubing string; electromagnetic coil assemblies disposed about the tube and equidistantly spaced along the length thereof; each of the coil assemblies comprising a coil circumfusing the tube, a first annular pole piece circumfusing the tube and positioned above the coil, a second annular pole piece circumfusing the tube and positioned below the coil, and a sleeve of magnetic material positioned about the coil and the first and second pole pieces and coextensive with the combined length thereof, a cylindrical case coextensive with and enclosing the tube and the coil assemblies; a separate mandrel of a non-magnetic material centrally positioned in the tube and removable therefrom; the mandrel having a central bore therein to permit the passage of production fluids therethrough; armature sections equidistantly spaced along the mandrel, the spacing being different from the spacing of the coil assemblies along the tube; the armature sections being formed as a stack of disks of a magnetic material; a plurality of annular centralizers separating the armature sections; a fishing neck on the mandrel, whereby the mandrel and the components attached thereto may be removed through the tubing string without removing the tubing and components attached thereto; and means for energizing the coil assemblies in a predetermined sequence, whereby electromagnetic attractive and repulsive forces are created between the coil assemblies and the armature sections to thereby move the mandrel longitudinally inside the tube.
- Assignee:
- NOV; NOV-87-077440; EDB-87-161549
- Patent Number(s):
- US 4687054
- OSTI ID:
- 6264000
- Country of Publication:
- United States
- Language:
- English
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