Ball Valve Enclosure Trunnion Support and Link Arm Protection
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Solution Overview
Problem
Ball valves often stall prematurely due to debris ingress, contamination, corrosion, and increased torque, leading to deformation and inoperability, especially in high-stress applications where conventional trunnion designs fail to provide adequate support and guidance.
Innovation Solution
A split-type enclosure with aligned apertures supports trunnions and features a unique profile for actuation arms and link arms, along with a preloading mechanism using bolts, to reduce overload and prevent debris entrapment, while an alignment ring ensures proper alignment and structural stability during operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional single plate trunnions are used to support the ball, then the structure is simple, but the trunnions deform under high friction and overload conditions
Solution Approach 1:
The enclosure is divided into multiple segments (first enclosure portion and second enclosure portion) that can be assembled together, allowing the complex strong enclosure structure to be manufactured and maintained more easily while providing enhanced support to the trunnions
Solution Approach 2:
The trunnions are positioned within apertures in the enclosure, with the enclosure portions nested around the ball and trunnions, creating a protective enclosure structure that supports the trunnions without adding external complexity
2Strength
If tight clearance is provided between the enclosure and ball, then support is maximized, but debris can settle and hinder ball rotation
Solution Approach 1:
Different clearance characteristics are provided at different locations: tight clearance at the apertures where trunnions are supported, and larger clearance in the ball passage area to prevent debris settlement, optimizing both support and operational smoothness
3Force
If the valve is designed for high stress applications, then it can handle increased torque, but it becomes more susceptible to deformation and failure
Solution Approach 1:
The preloading mechanism applies compressive force to the ball and trunnions before operation, creating a cushioning effect that prevents deformation under high torque loads and maintains reliability in high stress applications
Solution Approach 2:
The valve assembly combines multiple materials with different properties: the ball and trunnions use materials resistant to wear and corrosion, while the enclosure provides structural support, creating a composite structure that handles high torque reliably
4Strength
If the actuation arm and crosshead are connected without preloading, then assembly is simpler, but radial force from piston axial force causes deformation under stalled conditions
Solution Approach 1:
The preloading mechanism applies compressive force to the ball and trunnions before operation, creating a cushioning effect that prevents deformation under high torque loads and maintains reliability in high stress applications
Solution Approach 2:
The actuation arm and crosshead are pre-assembled with the ball and enclosure before final installation, allowing preloading and adjustment to be performed during assembly rather than requiring complex field adjustments
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 enhances the durability and reliability of ball valves by providing increased support and guidance to trunnions, reducing deformation and the likelihood of debris hindering operation, thus extending the valve's lifespan and maintaining functionality under high friction conditions.
Implementation Method 1
sleeve bearings connected to the ball via friction
Implementation Method 2
The bolts can create preloading between the actuation arm and crosshead to compensate for the radial force created by the piston axial force
Data Source
AI summary
A ball valve assembly includes an enclosure for supporting the ball valve during actuation. In one embodiment, the enclosure can be a split enclosure, and can have trunnion support apertures for engaging trunnions on the ball valve. In one embodiment, a pair of link arms are used to transfer force from a pair of actuation members to the ball valve. The link arms can be located in a recess on the actuation members, such the actuation members and the face of the trunnions define a cavity to enclose and protect the link arms.