Magnetic Coupling in Submersible Fluid Systems
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Solution Overview
Problem
Operating fluid systems submerged in deep seawater is challenging due to harsh conditions such as corrosion, extreme pressure, and thermal stress, as well as difficulties in maintenance and access in remote locations.
Innovation Solution
A submersible fluid system with a hermetically sealed electric machine housing and magnetic coupling between the electric machine rotor and fluid rotor, utilizing a non-magnetically conductive wall and gas or fluid bearings to withstand pressure and thermal loads, and a support system for the fluid-end housing to maintain alignment and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a magnetic coupling is used to transmit power from the electric machine rotor to the fluid rotor, then mechanical seals are eliminated and reliability is improved, but the complexity of the magnetic coupling structure increases
Solution Approach 1:
A non-magnetic, non-conductive barrier (such as a ceramic or plastic barrier) is introduced as an intermediary between the magnetic coupling components. This barrier allows magnetic flux to pass through while preventing direct contact between the magnetic fields and the fluid, thereby maintaining the reliability benefits of magnetic coupling while enabling practical implementation in wet environments.
Solution Approach 2:
The patent replaces traditional mechanical power transmission methods (such as shafts and mechanical seals) with a magnetic coupling system. This substitution eliminates the need for mechanical seals that would compromise reliability, while the magnetic field acts as the intermediary to transmit rotational force without physical contact.
2Reliability
If the electric machine and fluid-end are integrated into a single hermetically sealed housing, then protection against corrosion and pressure is improved, but heat dissipation becomes more difficult
Solution Approach 1:
The patent employs a hermetically sealed housing that acts as a protective barrier against corrosion and pressure while allowing for thermal management. The housing may incorporate thin-walled sections or heat-conductive materials that provide protection while facilitating heat transfer from the electric machine to the surrounding water environment.
Solution Approach 2:
The patent converts the previously harmful effect of water contact (corrosion and pressure) into a beneficial cooling mechanism. By hermetically sealing the electric machine while allowing the housing to be in direct contact with water, the system uses the water's thermal capacity for cooling while protecting internal components from corrosive effects.
3Reliability
If non-magnetic, non-conductive materials are used for the barrier between magnetic coupling components, then electrical conductivity is reduced and reliability is improved, but the structural strength may be compromised
Solution Approach 1:
The patent utilizes composite material structures for the non-magnetic, non-conductive barrier. These composites combine materials with complementary properties - such as ceramic matrices with fiber reinforcements - to achieve both the required electrical/non-magnetic properties and sufficient mechanical strength to withstand operating pressures and forces.
Solution Approach 2:
The barrier structure is designed to perform multiple functions simultaneously: providing electrical and magnetic isolation, withstanding mechanical pressure, facilitating heat transfer, and maintaining structural integrity. This multi-functionality is achieved through carefully selected materials and geometric designs that satisfy all requirements without compromise.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system effectively operates in deep water environments with reduced heat generation and energy consumption, minimizing the need for complex cooling systems and allowing for efficient transfer of heat and fluid management, thus enhancing reliability and maintenance accessibility.
Implementation Method 1
a magnetic coupling that couples the electric machine rotor and the fluid rotor, a magnet coupled to the electric machine rotor; a magnet coupled to the fluid rotor and in magnetic interaction with the magnet of the electric machine rotor
Implementation Method 2
an electric machine housing coupled to the fluid-end housing and comprising a hermetically sealed cavity
Data Source
Figure 1
Figure 2A
Figure 2B
AI summary
A submersible fluid system for operating submerged in a body of water includes a fluid-end that has a fluid rotor disposed in a fluid-end housing. An electric machine housing is coupled to the fluid-end housing and includes a hermetically sealed cavity. An electric machine, such as a motor and/or generator, is disposed entirely within the cavity of the electric machine housing. The electric machine includes an electric machine stator and an electric machine rotor. A magnetic coupling couples the electric machine rotor and the fluid rotor.