Submersible Pump Barrier Fluid Isolation Without Diaphragms
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Solution Overview
Problem
Electrical submersible pumps (ESPs) face challenges in maintaining separation between motor lubricant and pumped product when their densities are similar or when the pumped product's density is less than the motor lubricant's, without relying on bellows, diaphragms, or bladders, and without external lubricant pressurization systems.
Innovation Solution
The implementation of nested isolation chambers filled with a barrier liquid of higher density than both the motor lubricant and the pumped product, which allows for liquid exchange between the motor housing and the barrier chambers, ensuring separation without the need for additional separation components or pressurization systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a diaphragm is used to separate motor lubricant from pumped product, then separation reliability is improved, but device complexity and cost increase
Solution Approach 1:
The patent extracts the separation function from mechanical components (diaphragm, bellows) and implements it through density-based gravitational separation. The barrier fluid is removed from the motor housing, allowing pumped product to be expelled through interconnections without mechanical separation components.
Solution Approach 2:
The patent introduces a barrier fluid as an intermediary substance with density greater than both the motor lubricant and pumped product. This barrier fluid mediates the separation process by forming a dense layer at the bottom of the motor housing, preventing pumped product from contacting the motor lubricant through density stratification rather than mechanical barriers.
2Device complexity
If no diaphragm is used to reduce complexity, then device complexity is reduced, but risk of lubricant leakage into pumped product increases
Solution Approach 1:
The patent converts the potential harm of density differences into a beneficial separation mechanism. By ensuring the barrier fluid has the highest density, the system uses gravitational forces and density stratification to automatically prevent lubricant leakage without mechanical components, turning a potential problem into a reliable separation solution.
3Reliability
If barrier fluid with higher density is used, then separation effectiveness is improved, but fluid selection constraints increase
Solution Approach 1:
The patent changes the density parameter of the barrier fluid to be greater than both the motor lubricant and pumped product. This parameter change enables automatic separation through gravitational stratification, where the densest fluid (barrier fluid) settles at the bottom, preventing contact between the lighter fluids (lubricant and pumped product).
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
This solution effectively maintains separation between the motor lubricant and the pumped product, preventing contamination and ensuring reliable operation across various pumping applications without increasing complexity or cost.
Implementation Method 1
a barrier fluid that does not react with, nor mix with, the pumped product or the motor lubricant, and that has a significantly higher density than the pumped product and the motor lubricant
Implementation Method 2
due to the lower densities of the motor lubricant and the pumped product as compared to the barrier fluid, a separation is maintained between the pumped product and the motor lubricant
Implementation Method 3
Due to changes in temperature, the motor lubricant will expand during operation, and then contract when the pump is not running
Data Source
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AI summary
An electrical submersible pump (ESP) isolates its motor lubricant from pumped product without requiring a bellows, diaphragm, bladder, or external lubricant pressurizing system. A pair of nested isolation chambers below the motor housing are filled with a barrier fluid that is non-reactive, non-miscible, and higher in density than the pumped product and the motor lubricant. As the motor lubricant expands and contracts after pump start-up and shut-down, motor lubricant and barrier fluid are exchanged between the motor housing and the isolation chambers via three interconnections, while pumped product is exchanged with the inner barrier chamber, while being isolated from the motor housing. The interconnections extend between the bottom of the motor housing and the bottom of the outer barrier chamber, between the top of the outer barrier chamber and the bottom of the inner barrier chamber, and between the top of the inner barrier chamber and the pumped product.