ESP Diffuser and Impeller Tapers for Self-Alignment Under Thrust
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Solution Overview
Problem
Existing electrical submersible well pumps (ESP) experience misalignment issues between diffusers and the pump axis, leading to heat generation and wear due to slight annular clearances and misalignment of impellers, particularly in high-speed operations.
Innovation Solution
The diffusers and impeller hubs are designed with tapered shoulders that self-align and transfer thrust forces through tapered runners and bearings, ensuring proper alignment and reducing wear by utilizing a compressive force to maintain alignment and prevent direct thrust transfer between diffusers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If diffusers are stacked with perpendicular shoulders to transfer thrust forces, then thrust transfer capability is improved, but misalignment between diffusers and pump axis occurs due to annular clearance
Solution Approach 1:
The patent replaces the conventional perpendicular (flat) shoulders with tapered shoulders that have a curved surface geometry. The tapered surface allows for self-alignment of diffusers along the pump axis while maintaining thrust transfer capability, eliminating misalignment caused by annular clearance.
2Productivity
If impellers and diffusers operate at high speed to increase productivity, then pumping efficiency is improved, but heat generation increases due to misalignment and bearing friction
Solution Approach 1:
The tapered shoulder geometry enables precise alignment of impellers and diffusers during high-speed operation, reducing misalignment-induced friction and heat generation in bearings while maintaining high pumping efficiency.
3Ease of manufacture
If annular clearance is maintained between mating diffusers for ease of assembly, then ease of manufacture is improved, but misalignment and bearing heat generation occur
Solution Approach 1:
The tapered shoulder design allows diffusers to be self-aligning during assembly, maintaining ease of assembly with annular clearance while eliminating misalignment issues through the self-centering geometry of the tapered surfaces.
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 effectively centralizes the diffusers and impellers, reducing heat generation and wear, enhancing the operational efficiency and reliability of ESPs by maintaining precise alignment and distributing thrust forces efficiently.
Implementation Method 1
The tapered surfaces cooperate to transfer forces axially. The friction between the tapered surfaces prevents relative motion in directions other than axial, thereby maintaining alignment.
Implementation Method 2
The tapered surfaces cooperate to transfer forces axially. The normal force component along the taper facilitates axial force transfer while the geometry maintains alignment.
Data Source
Figure 1~3
Figure 2
Figure 4A
AI summary
An electrical submersible pump (12) has a stack of diffusers (25) within the housing (20), each of the diffusers having a conical upper shoulder (37) and a conical lower shoulder (43). The lower shoulder (43) of each of the diffusers (25) is in abutment with the upper shoulder (37) of an adjacent one of the diffusers (25). The upper and lower shoulders (37, 43) of each of the diffusers (25) slope downward and outward relative to the axis (23). Impeller hubs (95) have conical upper and lower ends (97, 99). At least some of the upper ends (97) of the hubs (95) abut and transfer up thrust to the lower end (99) of an adjacent one of the hubs. At least some of the lower ends (99) of the hubs (95) abut and transfer down thrust to the upper end (99) of an adjacent one of the hubs (95).