| 摘要 |
A submersible pump/sealed motor combination uses a magnetic coupling 68 to transmit motor drive 50 though a motor mounted partition wall 58 to the pump shaft 62. The magnets (neodymium iron-boron or samarium cobalt) may be arranged in rings and the partition may be non-magnetic material eg titanium, Hastelloy (RTM) or carbon reinforced PEEK. Mesh 70 reduces contamination of the coupling. The motor may be oil filled and expansion chamber containing a flexible element 80 is provided to compensate for thermal expansion. Alternatively bellows 86, bellows and an expansion chamber (Fig 8) or a piston (Fig 9) communicating with the well bore, may equalise pressure in the motor with that of the wellbore. Bearings 96-101 may be provided between the magnetic members and the partition and casings. Tilt pad, lemon bore of offset bearings can be used. |
