ESP Lubricant Pump Geometry for Single-Direction Bearing Protection
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Solution Overview
Problem
Existing electrical submersible pumps (ESPs) experience lubricant backflow when the shaft assembly reverses rotational direction, leading to debris flushing and potential damage to thrust bearings.
Innovation Solution
The ESP design incorporates a lubricant pump with a diffuser and impeller having oblique sidewalls and a frusto-conical shape, ensuring lubricant flow is directed away from the thrust bearing regardless of shaft rotation direction, using materials like PTFE and molecularly imprinted polymer, and optionally assembled as a separate insert.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If internal pumping means operates from shaft rotation, then lubricant distribution is achieved, but lubricant backflow occurs when shaft reverses direction causing debris to be carried to thrust bearing
Solution Approach 1:
The diffuser and impeller are designed with oblique sidewalls that reverse the expected flow behavior. When the shaft rotates in either direction, the oblique sidewalls redirect the lubricant flow away from the thrust bearing instead of allowing backflow toward it, effectively inverting the harmful backflow path into a protective flow pattern
Solution Approach 2:
The frusto-conical shape with oblique sidewalls creates an asymmetric flow path that is insensitive to rotation direction. This asymmetric geometry ensures that lubricant always flows away from the thrust bearing regardless of whether the shaft rotates clockwise or counterclockwise, eliminating the symmetric backflow problem
2Adaptability or versatility
If shaft assembly reverses rotational direction, then operational flexibility is improved, but lubricant backflow carries debris to thrust bearing causing damage
Solution Approach 1:
The design converts the potentially harmful effect of reverse rotation into a beneficial flow pattern. The oblique sidewalls of the diffuser and impeller ensure that even when the shaft reverses direction, the resulting lubricant flow is redirected away from the thrust bearing, transforming what would be a harmful backflow condition into a protective flow pattern that prevents debris accumulation
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 solution provides unidirectional lubricant flow, preventing debris backflush to thrust bearings, enhancing cooling and increasing power output by 15% compared to traditional systems.
Implementation Method 1
an impeller having a portion with an outer surface profiled complementary to the flow section and that is disposed within the flow section, so that when the impeller is rotated in any direction and with respect to the diffuser, lubricant flow is induced along the flow section in a direction away from an apex of the impeller
Data Source
AI summary
An electrical submersible pumping system (“ESP”) for use in a wellbore includes an electrical motor, a pump, a shaft coupled between the motor and pump, and a lubricant pump for circulating lubricant within the ESP. The lubricant pump includes a diffuser and an impeller that mounts onto and rotates with shaft rotation. A portion of the impeller has a frusto-conical outer surface, which is circumscribed by a portion of the diffuser profiled complementary to the frusto-conical portion of the impeller. The pump directs lubricant flow in a single direction irrespective of the rotational direction of the shaft.