Flexible Vane Centralizer for Rod String Stability
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Solution Overview
Problem
Spin-through centralizers in high rotational speed rod driven systems face issues with radial play due to undersized effective outer diameters, leading to rod string vibration and excessive wear, as they fail to maintain the rods at the centerline of the production tubing, especially in tubings with varying internal diameters.
Innovation Solution
A centralizer stator design with vanes that are flexible enough to deform and rebound to match the full specified internal diameter of the tubing, allowing passage through tight spots without damage, and maintaining the rod string at the centerline by having a cylindrical rotor within a stator with vanes that radially deform or circumferentially bend to accommodate diameter variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the stator effective outer diameter is reduced to allow passage through tight spots in tubing, then the ease of operation is improved, but the radial play increases and rod string stability deteriorates
Solution Approach 1:
The stator is designed with flexible vanes that can dynamically adjust their position. During installation, the vanes flex to accommodate reduced tubing diameters (tight spots). Once installed in normal tubing, the vanes return to their original position to provide full diameter support. This dynamic flexibility allows the stator to adapt to varying tubing conditions without compromising rod string stability during operation.
Solution Approach 2:
The stator's effective outer diameter parameter is made variable through the flexible vane design. The vanes can change their radial position based on tubing conditions, allowing the stator to effectively change its outer diameter from a reduced state (during passage through tight spots) to a full diameter state (during normal operation). This parameter change resolves the contradiction between ease of installation and operational stability.
2Stability of the object's composition
If the stator effective outer diameter is increased to maintain rod string stability, then the stability of the object's composition is improved, but the ease of operation deteriorates due to difficulty passing through tight spots
Solution Approach 1:
The flexible vane design enables the stator to transition between two effective outer diameter states. During installation, when encountering tight spots, the vanes flex inward to reduce the effective outer diameter, allowing passage. After passing through tight spots and being deployed in normal tubing, the vanes return to their original position to restore the full effective outer diameter for maintaining rod string stability.
Solution Approach 2:
The stator incorporates flexible vanes that act as flexible structural elements. These vanes can bend and deform to accommodate reduced tubing diameters during installation, then return to their original shape to provide full diameter support during operation. This flexibility allows the stator to overcome the contradiction between size and passability.
3Stability of the object's composition
If rigid stator vanes are used to maintain full tubing diameter contact, then the stability of the object's composition is improved, but the ease of manufacture and installation deteriorates due to damage risk in drift diameter tubing
Solution Approach 1:
The stator uses flexible vanes instead of rigid structures. This flexibility allows the vanes to deform and pass through drift diameter tubing without causing damage to either the centralizer or the tubing. After successful installation, the vanes maintain their full diameter configuration to ensure proper rod string stability. This eliminates the need to choose between rigidity for stability and flexibility for safe installation.
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 flexible stator design ensures stable rotation of the rod string by maintaining it at the centerline of the production tubing, reducing vibration and wear, while allowing safe passage through areas with reduced diameters without damaging the centralizer components.
Implementation Method 1
the stator has sufficient flexibility in the stator blades to allow the passage of said stator past areas of the tubing where the effective inside diameter is less than the specified ID of the tubing
Implementation Method 2
The materials used for the rotor and stator are chosen for both wear resistance and low coefficient of friction
Implementation Method 3
The materials used for the rotor and stator are chosen for both wear resistance and low coefficient of friction
Data Source
AI summary
A spin-through drive rod centralizer consisting of a stator constructed of plastic, or other appropriate material, which is mounted on a rotor attached to the body of the drive rod, which provides the bearing surface for rotation of the rotor within the stator. The stator is equipped with multiple vanes which extend to the full internal diameter of the production tubing. In one configuration, the radially oriented vanes have cut-outs which allow the tip of the vane to compress inward, allowing passage through tight spots in the tubing, then rebounding to the full ID of the tubing. In another configuration, the vanes are tangentially attached to the stator body, such that they bend in a circumferential direction to allow passage through tubing tight spots, then rebound to full tubing ID.