Guideless Downhole Valve Cage With Conical Flow Path
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Solution Overview
Problem
Downhole ball and seat valves in oilfield applications face issues with internal flow restrictions, ball lift acceleration, sticking, and packing off due to abrasive and corrosive environments, which lead to pump malfunctions and reduced flow rates.
Innovation Solution
A guideless valve cage with a conical internal configuration promotes laminar flow and minimizes ball impact, eliminating the need for internal guides and reducing the risk of solids packing, by allowing the ball to return smoothly to the seat through a full-open flow area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If internal ball guides are used to guide the ball, then ball travel is controlled and ball rattling is reduced, but flow restrictions increase and ball sticking occurs
Solution Approach 1:
The patent removes the internal ball guides from the valve cage design. By extracting this component, the flow path is opened up without restrictions, eliminating flow rate limitations while the ball is guided by the cage structure itself and returns to the seat through gravity and pressure differential
Solution Approach 2:
The patent introduces a magnet as an intermediary component to guide the ball's movement. The magnet, positioned at the bottom of the cage, attracts the ball to return to the closed position without requiring physical guides, thus maintaining full flow area while controlling ball travel
2Reliability
If ball guides are used to prevent ball rattling, then ball movement is controlled, but clearance becomes tight and trash/sand can wedge between ball and guide
Solution Approach 1:
The patent removes the internal ball guides that created tight clearances. Without these guides, there is no narrow gap for solids to wedge into, eliminating the packing off problem while the ball is still controlled by the cage geometry and magnetic attraction
Solution Approach 2:
The patent changes the clearance parameter from tight (with guides) to loose (without guides). This parameter change prevents solids from becoming trapped while the magnetic field and cage structure maintain adequate ball movement control
3Strength
If hardline is applied to ball guides to prevent beating out, then guide durability increases, but chips are generated and can impact pump operation
Solution Approach 1:
The patent removes the ball guides entirely, eliminating the source of chips that would be generated from hardline wear. The ball is guided by the cage structure and magnetic attraction rather than contact with hardlined guides
Solution Approach 2:
The patent replaces the mechanical ball guide system with a magnetic field-based guidance system. This substitution eliminates mechanical contact and chip generation while maintaining ball control functionality
4Productivity
If flow rate ratio is increased to improve flow, then flow rate increases, but turbulent flow occurs causing chaotic ball movement and cage beating
Solution Approach 1:
The patent removes the restrictive ball guides that created turbulent flow patterns. The resulting laminar flow allows the ball to move smoothly without chaotic movements that would beat out the cage
Solution Approach 2:
The patent changes the flow regime parameter from turbulent to laminar by removing restrictions. This parameter change stabilizes ball movement while maintaining adequate flow rate through the enlarged opening
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 conical design enhances flow efficiency, reduces ball lift and sticking, and prevents solids from causing pack-off, thereby extending the valve's operational life and maintaining flow rates in harsh environments.
Implementation Method 1
The conical configuration of the cage interior promotes laminar flow as the ball travels upwards
Implementation Method 2
The structural configuration also provides a 'nozzle effect' which helps the ball return to the seat
Data Source
AI summary
A cage for a down-hole valve for a hydrocarbon well has no internal guides for directing a ball as it travels from a closed position in which the ball is disposed against a ball seat to an open position where the ball is urged against a ball stop structure. The cage has an internal conical profile which inhibits ball sticking, reduces ball lift acceleration, and allows for a full-open flow area through the cage.