Diffuser Stack Interlock to Prevent ESP Diffuser Rotation
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Solution Overview
Problem
Conventional centrifugal pumps experience spinning diffusers due to inadequate compression or thermal expansion, leading to poor performance and premature failures.
Innovation Solution
The use of anti-rotation cast features on diffusers, such as protrusions, to prevent relative rotation between mating diffusers, achieved through casting and machining techniques to ensure tight tolerances and alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If compression is applied to the diffuser stack during assembly, then diffuser stability is improved, but device complexity increases
Solution Approach 1:
The patent employs asymmetric keyway features (protrusions and recesses) on the diffuser components. The drive shaft includes a keyway that mates with a corresponding keyway on the impeller, creating an asymmetric mechanical interlock that prevents relative rotation between these components. Similarly, the diffuser stack includes keyed features that prevent rotation between adjacent diffusers. This asymmetric design provides rotational stability without requiring complex external restraint mechanisms.
2Stability of the object's composition
If compression is applied to the diffuser stack during assembly, then diffuser stability is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent incorporates pre-designed compression features into the diffuser stack assembly. The diffusers are equipped with stepped surfaces and corresponding compression rings that apply predetermined axial compression forces during assembly. This preliminary action ensures the diffusers remain compressed and stable during operation without requiring precise manual compression adjustments, thereby reducing manufacturing precision requirements while maintaining stability.
3Adaptability or versatility
If the pump is subjected to high temperatures, then thermal expansion occurs causing compression loss, but operational versatility is improved
Solution Approach 1:
The patent incorporates thermal expansion compensation features in the diffuser stack design. The housing and diffuser components are designed with clearances and expansion spaces that accommodate thermal expansion at high temperatures. The compression rings and keyed features are positioned to maintain their restraining function even when components expand thermally, ensuring compression retention and preventing diffuser rotation during high-temperature operation.
4Stability of the object's composition
If keyed features are added to prevent rotation, then diffuser stability is improved, but device complexity increases
Solution Approach 1:
The patent merges the anti-rotation function with the existing structural components of the pump. The keyed features (protrusions and recesses) are integrated into the drive shaft, impeller, and diffuser stack assemblies rather than being separate added components. This merging approach provides rotational stability while minimizing increases in overall device complexity, as the anti-rotation features become part of the normal structural architecture.
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
Prevents diffuser rotation, improving pump performance and preventing premature failure, especially in high-temperature environments.
Implementation Method 1
The use of anti-rotation cast features on diffusers, such as protrusions, to prevent relative rotation between mating diffusers
Data Source
AI summary
A diffuser stack for a centrifugal pump includes a first diffuser including a first rim having a first inner circumferential surface, a first outer circumferential surface, and protrusions extending radially inward from the first inner circumferential surface. The diffuser stack further includes a second diffuser including a second rim having a second inner circumferential surface and a second outer circumferential surface. Recesses are formed in the second diffuser. The recesses extend radially inward from the second outer circumferential surface. The second diffuser is configured to engage the first diffuser such that the second outer circumferential surface engages the first inner circumferential surface and the protrusions engage the recesses.