Subsea Fluid Pump Magnetic Coupling and Sealed Casings
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Solution Overview
Problem
Existing fluid pump systems face challenges in being environmentally friendly, minimizing leakages, and optimizing fluid usage, especially when submerged in seawater, while maintaining conventional stator and rotor designs and functionality.
Innovation Solution
A fluid pump system with an electrical drive unit and rotary pump design using environmentally friendly fluids for lubrication and cooling, featuring static seals and pressure-balanced casings to prevent leakage, where the stator is enclosed in one casing with a non-magnetic common barrier and the rotor in another, both sealed with static seals, utilizing green fluids for lubrication and cooling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional electrically driven pumps are used, then proven stator and rotor designs can be utilized, but environmental contamination and fluid leakage occur
Solution Approach 1:
The pump system is divided into separate sealed compartments: the electrical drive unit with its own sealed casing containing electrical fluid, and the pump unit with its own sealed casing containing green lubricant. This segmentation prevents mixing of fluids and isolates potential leakage sources, allowing conventional proven designs to be used while preventing environmental contamination through physical separation and sealing.
2Device complexity
If a single fluid is used for both electrical protection and lubrication, then system simplicity is maintained, but fluid optimization for different functions is compromised
Solution Approach 1:
Different fluids are used in different locations within the system: electrical fluid (oil) in the sealed electrical drive unit for electrical protection and insulation, and green lubricant in the sealed pump unit for lubrication and cooling. This local differentiation allows each fluid to be optimized for its specific function while the overall system complexity is managed through modular sealed compartments.
3Adaptability or versatility
If the pump system is submerged in seawater, then subsea application requirements are met, but leakage risk and environmental impact increase
Solution Approach 1:
The sealed casings act as intermediary barriers between the internal system fluids and the external seawater environment. The electrical drive unit casing seals in the electrical fluid and protects electrical components from seawater, while the pump unit casing seals in the green lubricant. These intermediary seals prevent seawater ingress and internal fluid leakage, enabling subsea deployment without increasing environmental impact.
4Stress or pressure
If pressure-tight enclosures with rotating seals are used, then subsea pressure resistance is achieved, but leakage points and maintenance complexity increase
Solution Approach 1:
The design extracts and eliminates rotating seals from the system by using magnetic coupling for power transmission across the casing boundary. The electrical rotor drives the pump shaft magnetically through the casing wall without physical contact, removing the need for rotating seals that would create leakage paths. Only static seals are used at flange connections, dramatically reducing leakage risk and maintenance complexity while maintaining pressure resistance.
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 prevents environmental contamination by minimizing leakage and optimizing fluid usage, maintaining high pressure integrity and efficiency even under high pipeline pressures, while ensuring the electrical components are protected from seawater exposure.
Implementation Method 1
a magnetic coupling arrangement for coupling the electrical rotor to the pump shaft
Implementation Method 2
a fluid balance chamber for substantially maintaining equal pressure in the first casing and the second casing
Implementation Method 3
a first external fluid cooling circuit comprising an inlet section connected to the first casing, and an outlet section connected to the first casing; and means for causing the flow of fluid from within the first casing through the first external cooling circuit
Data Source
AI summary
A fluid pump system comprises an electrical drive unit and a rotary pump comprising a rotatable shaft and a drive element formed from a number of impellers attached to the shaft for causing flow within a process fluid. The electrical drive unit comprises an electrical stator and an electrical rotor attached to the shaft via a coupling, the electrical stator being disposed adjacent to the electrical rotor. The electrical stator is disposed within a first casing and the rotary pump and the electrical rotor are disposed within a second casing. The first casing contains a first fluid and the second casing contains a second fluid.