SMA Clamp Rings for ESP Bladder Sealing
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Solution Overview
Problem
Existing electrical submersible pumps (ESP) face issues with bladder leaks due to insufficient clamping force during assembly, and excessive stress applied by clamps can damage the bladder. Additionally, thermal cycling causes clamps to loosen, leading to potential leaks and operational failures.
Innovation Solution
The use of shape memory alloy (SMA) clamp rings that can be heated to expand and then contract to securely attach the bladder to adapters, providing a consistent and adjustable clamping force without damaging the bladder. The SMA alloy allows the clamp rings to revert to their expanded state at low temperatures, facilitating easy installation and removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If manual clamps are tightened to exert sufficient clamping force on the bladder ends, then leakage is prevented, but the bladder may be damaged due to excessive stress
Solution Approach 1:
The clamp ring utilizes temperature-dependent parameter changes in shape memory alloy material. At installation temperature, the alloy is in an austenitic phase with specific mechanical properties allowing safe installation. Upon heating to the transformation temperature range, the alloy transforms to martensitic phase, changing its dimensional and mechanical parameters to provide the required clamping force without exceeding bladder stress limits.
Solution Approach 2:
The clamp ring is pre-formed with an expanded inner diameter at room temperature, allowing it to be installed over the bladder end before contraction. This preliminary expanded state enables safe installation without pre-applying damaging stress to the bladder, and the contraction to provide clamping force occurs after installation is complete.
2Adaptability or versatility
If thermal cycling occurs during ESP operation, then material expansion and contraction create forces, but these forces can exceed clamp material properties causing clamps to loosen
Solution Approach 1:
The shape memory alloy clamp ring exploits reversible phase transitions between austenitic and martensitic structures. During thermal cycling, the alloy undergoes phase transitions at specific temperature ranges, allowing it to absorb and accommodate thermal expansion/contraction forces. The phase transition mechanism enables the clamp to maintain retention reliability by transforming its internal structure rather than relying solely on mechanical resistance to thermal forces.
3Ease of operation
If discontinuity is introduced in the clamp to allow for slippage during installation, then installation is facilitated, but pressure distribution becomes uneven creating areas of lower or higher pressure that can lead to leaks or tears
Solution Approach 1:
The clamp ring provides dynamic adaptability through the shape memory effect. During installation in the expanded state, the clamp can accommodate slight movements and adjustments. Once heated and contracted, the material's superelastic properties allow it to dynamically adjust to the bladder end geometry, distributing pressure evenly while maintaining sufficient clamping force to prevent leakage without causing tears.
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 SMA clamp rings effectively prevent leaks by maintaining a consistent clamping force, while also allowing for easy installation and removal, reducing the risk of damage to the bladder and ensuring reliable operation of the ESP even under thermal cycling conditions.
Implementation Method 1
The first clamp ring is formed of a shape memory alloy that causes movement from the expanded condition to the contracted condition in response to heating the first clamp ring to a selected elevated temperature
Implementation Method 2
The first clamp ring is movable from the contracted condition back to the expanded condition in response to chilling the first clamp ring to a selected low temperature
Data Source
AI summary
An electrical submersible pump assembly has a seal section housing for coupling between a motor and a pump of the assembly. A bladder has an opening sized to slide over an adapter in the seal section housing. A clamp ring is formed of a shape memory alloy selected to create an expanded condition inner diameter when at a room temperature, enabling the clamp ring to be inserted over the bladder opening during assembly. When heated to a selected elevated temperature, the clamp ring contracts and tightly secures the opening around the adapter. The shape memory alloy of the clamp ring also causes the contracted condition inner diameter to expand when chilled to a selected low temperature. Maximum and minimum diameters of the contracted ring are based on an amount of bladder compression that achieves sealing without damage to the bladder.