Actuator Housing Shear Connection for Overpressure Choke
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current chokes in the oil and gas industry are prone to failure due to overpressure conditions when used as closing valves, leading to stem breakage and internal/external damage, as they are not designed to handle such pressures effectively.
Innovation Solution
A choke design featuring an actuator assembly with a shearing connection and a thrust bearing to direct overpressure loads within the housing, combined with a worm gear system to securely lock the stem position, preventing stem movement during pressure surges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the choke is used as a closing valve to entirely close the stem against the seat, then the flow is completely blocked, but the force required to close the stem breaks the stem or shear pin, rendering the choke useless
Solution Approach 1:
The connection between the actuator housing and actuator adapter is segmented into multiple threaded fasteners distributed around the circumference, distributing the closing force across multiple attachment points rather than concentrating it on a single stem or shear pin location
Solution Approach 2:
The attachment mechanism transitions from axial loading (along the stem axis) to radial/shear loading through the threaded connection between actuator housing and adapter, changing the dimensional orientation of force application to avoid stem breakage
2Strength
If a shear pin is included to break before the stem, then the stem is protected, but the choke remains useless until repaired
Solution Approach 1:
The threaded connection between actuator housing and adapter is designed with sufficient shear strength to withstand overpressure surges before any failure mode is reached, providing a cushioning reserve that prevents catastrophic failure and maintains choke availability
Solution Approach 2:
The design eliminates disposable components like shear pins that require replacement; instead, the permanent threaded connection is designed to be reusable and maintainable, improving long-term reliability without sacrificing protection
3Stress or pressure
If the downstream pressure area is larger than the upstream pressure area, then the pressure differential can be handled, but the larger force on downstream components causes choke failure and breakage
Solution Approach 1:
The threaded connection between actuator housing and adapter provides a counteracting shear strength that balances the larger downstream force, creating an equilibrium that prevents choke component failure despite the pressure area differential
Solution Approach 2:
The threaded connection acts as an intermediary element between the actuator components and the choke body, mediating the force transmission and distributing the large downstream forces through the thread engagement rather than concentrating them on vulnerable choke components
4Stability of the object's composition
If a worm gear transverse to the threaded shaft is attached to hold the stem in position, then some position stability is achieved, but the choke can still fail with overpressure conditions
Solution Approach 1:
The design merges the positioning function and overpressure resistance function into a single integrated threaded connection system, where the same threads that secure the actuator also provide the shear strength to resist overpressure surges, eliminating the need for separate locking mechanisms
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 resists large overpressure surges and maintains the choke's integrity by restraining forces through axially-oriented threads and a thrust bearing, reducing the risk of failure and stem breakage.
Implementation Method 1
a force resulting from fluid pressure inside the actuator housing from the choke is restrained from separating the actuator housing from the actuator adapter by a strength of the threads in an axially-oriented shear direction across the threads
Implementation Method 2
a thrust bearing mounted adjacent a shoulder in the housing and supporting a worm gear, so that any overpressure loads are directed to the shoulder of the housing and retained within the housing
Implementation Method 3
a worm gear coupled to the actuator housing and having inner threads and outer teeth, the inner threads configured to engage the lift shaft threads
Implementation Method 4
a lift shaft coupled to the actuator housing, the lift shaft having threads formed thereon
Data Source
AI summary
The disclosure provides a choke with an actuator that contains various components within an actuator housing to adjust the choke, and the housing is configured to be fixedly attached with a relatively large shearing connection on an actuator adapter to resist large overpressure surges within the housing and around the components. The actuator further includes a thrust bearing mounted adjacent a shoulder in the housing and supporting a worm gear, so that any overpressure loads are directed to the shoulder of the housing and retained within the housing while the housing is retained by the shearing connection to the remainder of the choke.