Anti-Rotation Bearing Bushing for Sand-Heavy ESP Stages
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Solution Overview
Problem
Existing bearing assemblies in electric submersible pumps (ESPs) fail to adequately prevent rotation of the bushing under adverse conditions such as high torque, leading to potential failure and loss of functionality in unconventional wells with extreme sand concentrations.
Innovation Solution
The proposed bearing assembly incorporates a keyed bushing with an external key that engages a corresponding keyway in the diffuser, combined with an axial retaining part like a retaining ring, to prevent rotation and minimize stress concentrations, using materials like stainless steel or Monel for enhanced strength, and features such as an eccentric or oblique profile to secure the bushing within the bearing housing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional bushing is used in the bearing assembly, then the structure is simple and easy to manufacture, but the bushing rotates under high torque conditions leading to failure
Solution Approach 1:
The bushing incorporates an asymmetric key structure that protrudes radially outwardly to engage with a corresponding keyway in the diffuser. This asymmetric feature prevents rotational movement by creating a mechanical interlock that resists torque forces, thereby resolving the contradiction between maintaining structural simplicity and preventing bushing rotation under high torque conditions.
2Reliability
If a keyed bushing with anti-rotation feature is added, then the bushing is secured against rotation under high torque, but the device complexity increases
Solution Approach 1:
The bushing is segmented into distinct functional features: a cylindrical body for radial positioning, a radially protruding key for anti-rotation engagement, and an axial retaining part for axial positioning. This segmentation allows each feature to perform its specific function efficiently while keeping the overall design modular and manufacturable, addressing the contradiction between enhanced reliability and device complexity.
3Strength
If materials like stainless steel or Monel are used for the bushing, then the strength and durability are enhanced, but the manufacturing cost increases
Solution Approach 1:
The patent specifies using materials like stainless steel or Monel for the bushing, which are known for their high strength, corrosion resistance, and durability. This material selection changes the physical and chemical parameters of the bushing to withstand harsh well environments including high torque and sand concentrations, justifying the increased manufacturing cost through improved reliability and longevity.
Data Source
AI summary
Anti-rotation bearing assemblies for electric submersible pumps are provided. An electric submersible pump includes a plurality of centrifugal pump stages, each stage including a rotating impeller and a stationary diffuser mounted on a shaft coupled to a motor. In use, the motor rotates the shaft, which rotates the impeller within the stationary diffuser. A bearing assembly can include a bearing sleeve disposed about the shaft and a bushing disposed radially between the bearing sleeve and the diffuser. The bearing sleeve rotates with the shaft in operation, and the bushing remains stationary with the diffuser. The bushing can have an external key that is received in a key way or groove in the diffuser to act as an anti-rotation feature. In other variations, the bushing can have an eccentric or oblique profile, which can act as an anti-rotation feature.