Plug Valve Alignment Under Thermal Expansion
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Solution Overview
Problem
Plug valves used in oil or gas operations face misalignment issues due to thermal expansion and axial forces, leading to wear, erosion, or complete wash-out of components.
Innovation Solution
A plug valve design incorporating a valve body with a tapered insert and plug, a biasing member constrained between the bonnet and insert, and interlocking annular features to maintain alignment and prevent leakage, utilizing a metal ring seal and lubrication ports for sealing and lubrication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the plug valve operates under extreme pressures and temperatures, then the valve can handle high-flow-rate oil or gas operations, but thermal expansion causes misalignment between fluid passages leading to wear and erosion
Solution Approach 1:
The valve is divided into separable components (plug, insert, body) that can independently accommodate thermal expansion. The plug can expand within the insert cavity without transferring stress to the fluid passages, maintaining alignment while handling extreme operating conditions.
Solution Approach 2:
The plug is nested within the insert, which is nested within the valve body. This nested structure allows the inner components to expand independently within the outer components, absorbing thermal expansion effects and preventing misalignment of fluid passages during high-temperature operation.
2Stress or pressure
If axial forces such as hydraulic lift are imparted to the insert and plug, then the valve can operate under high pressure, but these forces urge the fluid passages out of alignment causing wear and erosion
Solution Approach 1:
The valve components are segmented into the plug, insert, and body, allowing each to respond independently to axial forces. The insert acts as an intermediate element that absorbs and distributes hydraulic lift forces, preventing direct transmission to the fluid passage alignment.
Solution Approach 2:
The insert serves as an intermediary element between the plug and valve body. It mediates the transmission of axial forces, absorbing hydraulic lift through its positioning features and preventing these forces from disrupting the alignment between the plug and body fluid passages.
3Ease of operation
If the plug and insert are allowed to rotate for flow control, then the valve can selectively prevent or allow fluid flow, but rotation under pressure causes misalignment and wear
Solution Approach 1:
The rotation function is segmented and isolated to the plug component, which rotates within the stationary insert. This segmentation allows the plug to rotate for flow control while the insert remains fixed, preventing rotational forces from affecting the alignment of the fluid passages in the insert and body.
Solution Approach 2:
The stationary insert acts as an intermediary that decouples the rotation of the plug from the fluid passage alignment. It provides a stable reference frame for the rotating plug while maintaining fixed alignment with the valve body, allowing rotation without misalignment.
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 design effectively maintains alignment under extreme conditions, reducing wear and leakage, and preventing the wash-out of components, ensuring reliable operation despite thermal expansion and axial forces.
Implementation Method 1
a biasing member constrained between the bonnet and the insert, the biasing member urging the insert into engagement with the valve body
Implementation Method 2
a metal ring seal adapted to prevent leakage of a fluid from an interior of the valve body
Data Source
AI summary
A plug valve including a valve body defining a cavity and a pair of fluid passages intersecting the cavity, the cavity defining a tapered interior surface of the valve body, a plug extending within the cavity, the plug defining an exterior surface and a fluid passage adapted to be substantially aligned with the fluid passages of the valve body, and an insert extending within the cavity and circumferentially about at least a portion of the plug, the insert defining a pair of fluid passages substantially aligned with the fluid passages of the valve body, respectively. In several exemplary embodiments, the plug valve is used in oil or gas operations, such as, for example, the fracturing or gravel packing of a subterranean wellbore, with the plug valve being used to control the flow of fracturing and/or gravel-packing fluids. Exemplary embodiments of methods associated with the plug valve are also described.