Torque Transmitting Rings for ESP Sleeve Vibration
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Solution Overview
Problem
Electrical submersible pump assemblies face issues with stress concentration and thermal expansion differences between steel alloy shafts and abrasion-resistant components, leading to potential cracking and excessive vibration during startup due to mismatched thermal expansion coefficients.
Innovation Solution
Incorporating deformed torque transmitting rings made of elastomeric or resilient materials between the shaft and sleeve, which creates sufficient friction for unison rotation without the need for keyways, thereby reducing stress concentrations and accommodating thermal expansion differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a keyway is formed in the abrasion-resistant sleeve to transmit torque, then torque transmission is achieved, but stress concentration occurs that can cause the sleeve to crack
Solution Approach 1:
The invention extracts the torque-transmitting function from the sleeve material itself and relocates it to a separate elastomeric ring component. The keyway is removed from the abrasion-resistant sleeve and replaced with a groove that receives an elastomeric ring, which then performs the torque transmission function through friction rather than mechanical key engagement.
Solution Approach 2:
An elastomeric ring is introduced as an intermediary component between the shaft and the abrasion-resistant sleeve. This ring serves as a mediator that transmits torque through frictional contact, eliminating the need for a keyway in the sleeve while preserving both torque transmission capability and sleeve structural integrity.
2Temperature
If excessive clearance is provided between the shaft and abrasion-resistant component to accommodate thermal expansion, then thermal expansion differences are accommodated, but looseness and excessive vibration occur during startup
Solution Approach 1:
The elastomeric ring provides a dynamic solution to the thermal expansion problem. During startup at ambient temperature, the ring maintains sufficient frictional contact to prevent excessive vibration. As the system heats up and thermal expansion creates clearance, the elastomeric material's compliance allows it to maintain continuous contact and torque transmission without causing vibration issues.
Solution Approach 2:
The invention changes the friction parameter dynamically through the elastomeric ring's material properties. The ring's coefficient of friction and compliance allow it to adapt to changing clearance conditions caused by thermal expansion, maintaining stable torque transmission across the temperature range without the looseness problems of rigid clearance designs.
3Reliability
If initial clearance is made sufficiently large to prevent mechanical damage during startup, then thermal expansion is accommodated, but looseness occurs until full operating temperature is reached
Solution Approach 1:
Instead of using a rigid metal-to-metal clearance fit, the invention uses an elastomeric ring that copies and softens the clearance accommodation function. The elastomeric material provides the necessary compliance to handle thermal expansion while maintaining continuous contact, effectively copying the clearance accommodation function without the harmful looseness associated with rigid clearance designs.
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 reduces the risk of mechanical damage and vibration by providing a large initial clearance that accommodates full thermal expansion, ensuring smooth startup and operation without the need for torque transmitting shoulders in abrasion-resistant materials.
Implementation Method 1
The deformation of the ring creates a frictional force sufficient to cause the sleeve to rotate in unison with the shaft assembly
Implementation Method 2
The steel alloy shafts have a much higher coefficient of thermal expansion than either carbide or ceramic materials used in AR components. Because of the differences in thermal expansion, excessive clearances need to be provided between the shaft and AR component
Data Source
AI summary
An electrical submersible pump assembly has a motor module coupled to a centrifugal pump module by a seal section module. A shaft assembly extends through each of the modules for causing the motor module to rotate the pump module. At least one of the modules has a sleeve extending around the shaft that is of a harder material than the shaft. A torque transmitting ring is deformed between an inner diameter of the sleeve and an exterior portion of the shaft. The inner diameter of the sleeve is a continuous cylindrical surface free of any torque transmitting shoulders. Friction created by the torque transmitting ring transmits the entire rotational force from the shaft to the sleeve.