SMA Foil Seal Assembly for Submersible Pump Motor Protection
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Solution Overview
Problem
Conventional submersible pumping systems face issues with contamination of motor fluid due to ingress of wellbore fluids, particularly under high temperature conditions, which degrades the dielectric strength and leads to motor failure.
Innovation Solution
A seal assembly incorporating a shape memory alloy (SMA) foil or metal foil surrounding a support tube within a housing, creating a chamber to store motor fluid and restrict the flow of wellbore fluids, while accommodating thermal expansion and contraction, thus preventing contamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a motor protector is used to shield the motor from wellbore fluids, then the motor is protected from direct fluid contact, but under high temperature the motor protector becomes permeable to water molecules allowing fluid ingress
Solution Approach 1:
The patent employs a flexible bladder made of elastomeric material that expands and contracts to maintain sealing contact with the motor protector inner surface. This flexible membrane prevents fluid ingress through the permeable motor protector by creating a physical barrier that adapts to thermal expansion and contraction, solving the high-temperature permeability problem while maintaining motor protection.
Solution Approach 2:
The patent utilizes the thermal expansion and contraction properties of the elastomeric bladder material to maintain sealing effectiveness across temperature variations. As temperature changes cause the motor protector to expand or contract, the elastomeric bladder responds by expanding or contracting accordingly, maintaining continuous contact and preventing fluid penetration through the permeable structure.
2Reliability
If a rigid seal structure is used to prevent fluid ingress, then sealing effectiveness is improved, but the structure cannot accommodate thermal expansion and contraction of the motor fluid
Solution Approach 1:
The patent replaces rigid seal structures with a dynamic, flexible bladder system that can adapt its shape and volume in response to thermal changes. The elastomeric material allows the seal to expand when the motor fluid expands due to heating and contract when the fluid cools, maintaining sealing effectiveness throughout the thermal cycle without requiring a complex rigid structure.
Solution Approach 2:
The flexible elastomeric bladder acts as a compliant seal that conforms to the motor protector inner surface while accommodating volume changes in the motor fluid. This flexible shell approach provides both effective sealing and thermal adaptability, eliminating the need for rigid structures that would fail under thermal expansion conditions.
3Reliability
If the motor protector is made impermeable to prevent fluid ingress, then fluid restriction is improved, but the structure cannot accommodate thermal expansion of the motor fluid
Solution Approach 1:
The patent nests the flexible bladder inside the motor protector, creating a layered structure where the bladder provides the impermeable seal while the motor protector provides the structural housing. This nested arrangement allows the bladder to expand and contract within the motor protector volume, accommodating thermal expansion without requiring additional external space or increasing overall device complexity.
Solution Approach 2:
The flexible elastomeric bladder provides an impermeable barrier to fluid ingress while its compliance allows it to expand and contract with thermal changes. This flexible shell solution achieves both fluid restriction and thermal expansion accommodation within the existing motor protector volume, avoiding the need for additional space or complex structural modifications.
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
Effectively isolates motor fluid from wellbore fluids, maintaining dielectric strength and preventing motor failure even under extreme temperature and pressure conditions, ensuring the submersible pumping system's reliability.
Implementation Method 1
a shape memory alloy (SMA) foil disposed within the housing, surrounding the support tube to define a first chamber between the shape memory alloy foil and the support tube
Implementation Method 2
the shape memory alloy foil is configured to restrict a flow of a wellbore fluid to the motor fluid
Data Source
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AI summary
A seal assembly for a submersible pumping system is presented. The seal assembly includes a housing and a support tube disposed within the housing. Further, the seal assembly includes a shape memory alloy (SMA) foil disposed within the housing, surrounding the support tube to define a first chamber between the shape memory alloy foil and the support tube. The first chamber is configured to store a motor fluid, and wherein the shape memory alloy foil is configured to restrict a flow of a wellbore fluid to the motor fluid.