Progressive Cavity Motor Dampening via Segmented Elastomer Liner
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Solution Overview
Problem
Moineau-type pumps and motors used in directional drilling experience motor failure due to excessive lateral and shear forces on the rubber or elastomer seals, leading to issues like rubber chunking, which reduces motor durability and efficiency.
Innovation Solution
Incorporating a liner with sections of varying compressibility into the stator and rotor, including a compression-resistant mechanism like a spring or spring-like device, to absorb and manage rotor movement, reduce contact forces, and mitigate bending and twisting, thereby enhancing durability and sealing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a rubber or elastomer liner is used in the stator to seal the moving chamber, then sealing efficiency is improved, but excessive lateral and shear forces cause rubber chunking and motor failure
Solution Approach 1:
The liner is divided into multiple axial sections with different material properties. The first section (near the inlet) uses a softer elastomer to reduce lateral forces, while the second section (near the outlet) uses a harder elastomer to withstand higher pressures. This segmentation allows each section to be optimized for its specific operational conditions, reducing overall stress on the elastomer material.
Solution Approach 2:
Different sections of the liner have different material characteristics tailored to local requirements. The softer first section provides better dampening and force reduction where the rotor experiences more lateral movement, while the harder second section provides structural integrity where pressure forces are concentrated. This local differentiation resolves the contradiction between sealing efficiency and force resistance.
2Reliability
If the rotor is constrained to reduce movement, then contact forces are reduced, but motor efficiency and power generation decrease
Solution Approach 1:
The liner material properties are changed along the axial direction, with the first section having different elastomeric properties than the second section. This parameter change allows the liner to provide variable constraint levels - softer near the inlet to allow more movement and reduce forces, harder near the outlet to maintain sealing under pressure - thereby maintaining power generation while reducing lateral forces.
3Ease of manufacture
If a single-material liner is used, then manufacturing is simplified, but the liner cannot simultaneously reduce forces and maintain sealing under varying pressure conditions
Solution Approach 1:
The liner is constructed as a composite structure with multiple axial sections made from different elastomeric materials or with different physical properties. This composite approach allows the liner to exhibit both force-reducing characteristics in the first section and high-pressure sealing characteristics in the second section, achieving multiple functions that a single-material liner cannot provide.
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 reduces lateral and shear forces on the elastomer seals, prolonging motor life and maintaining power generation and fluid transport capabilities, while allowing for greater freedom of movement to prevent motor failure.
Implementation Method 1
a compression resistant mechanism disposed within at least one of the axial sections of the liner. In at least one implementation, the compression resistant mechanism is a spring or spring-like device
Implementation Method 2
Incorporating a liner with sections of varying compressibility into the stator and rotor... to absorb and manage rotor movement, reduce contact forces
Data Source
AI summary
A rotor and/or stator dampening system includes a stator and/or rotor with a liner selected of one or more materials to achieve a desired dampening effect. In one implementation, a progressive cavity motor or pump includes a stator with an internal axial bore therethrough. The stator has a liner along an axial length thereof with an inwardly facing surface defining the internal axial bore therethrough. The liner has a plurality of axial sections with at least two of the plurality of axial sections being constructed of different materials. A compression resistant mechanism, such as a spring or spring-like device, is disposed within at least one of the axial sections of the liner. The progressive cavity motor or pump also includes a rotor that is disposed and is rotatable within the internal axial bore of the stator to form a moving chamber between the rotor and the stator.