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Magnetic Torque and Thrust Coupling Disclosure Number: IPCOM000244504D
Publication Date: 2015-Dec-17
Document File: 5 page(s) / 310K

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The Prior Art Database

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Page 01 of 5

Magnetic Torque and Thrust Coupling

This disclosure is directed towards a magnetic coupling that transmits both torque and axial (thrust) loads across shafts without direct shaft contact.

Typical submergible pumping systems consist of a motor, protector and pump connected together with a central shaft. The protector unit serves the function of handling thermal expansion of oil, equalizing internal motor pressure with well pressure, supporting thrust created by the pump and sealing the motor from well fluid. One end of the protector is communicated to the motor while the other is open to the wellbore. Circumstances such as wear, thermal cycling, component and seal failures can result in malfunction of the protector. This malfunction ultimately causes wellbore fluids to enter the motor and cause a total ESP failure.

Having a magnetic coupling that connects the motor to the protector shaft effectively bypasses the necessity of having a protector open to the well fluids, in which case the motor can be sealed. The shaft connection has to be able to transmit both torque and thrust loads in order to better replace the protector functions. One aspect of the present disclosure is a method on how to also transmit thrust loads through the magnetic coupling (in addition to torque loads).

Figure 1a shows a schematic of the magnetic coupling stacking. To increase the amount of torque capable of transmitting, magnetic coupling stages are stacked vertically for increase strength. Figure 1b shows the typical radial polarity arrangements of each magnetic coupling of the stack. Note that the radial polarity arrangement of the magnets is the commonly used radial arrangement that gives maximum torque capacity.

Page 02 of 5

1a. 1b.

Figure 1. a) Magnetic coupling stack and b) Cross-section showing radial magnetic orientation

Axial polarity arrangement is very important because it can create thrust loading capabilities. Figure 2a shows axial polarity arrangement where axial torque transmission is not present, a torque-only magnetic couplin...