Eccentric Control Valve Stem Retention Against High-Pressure Blowout
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Solution Overview
Problem
Eccentric process control valves used in high pressure applications face challenges in preventing the valve stem from blowing out of the valve body, with existing solutions involving multiple valve body pieces leading to inefficiencies.
Innovation Solution
A unitary valve body design with a bonnet and a bore, featuring a shoulder to prevent the retainer from passing through, and a rotationally fixed retainer and valve stem connection to resist blowout, along with a sleeve bearing and flange for additional support.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a multiple-piece valve body design is used to prevent valve stem blowout, then reliability is improved, but device complexity increases
Solution Approach 1:
The valve body is divided into a main body and a separate bonnet component. The bonnet contains a bore with a shoulder that provides mechanical retention for the valve stem, while the main body contains the valve seat and flow passages. This segmentation allows the retention function to be isolated to a specific component without complicating the entire valve body structure.
Solution Approach 2:
The bonnet acts as an intermediary component between the valve stem and the external environment. It provides a controlled passage (bore) through which the valve stem extends, and the shoulder within the bore provides mechanical retention. This intermediary structure prevents direct exposure of the valve stem to high pressure forces while maintaining operational access.
2Strength
If a larger valve stem is used to prevent blowout, then strength is improved, but ease of operation deteriorates
Solution Approach 1:
The valve stem has varying cross-sectional dimensions along its length. The portion within the bonnet bore has a smaller diameter for ease of manipulation and actuation. The retained portion at the end of the bore has a larger diameter or is mechanically retained by the shoulder, providing strength against blowout forces without compromising operational ease.
3Ease of manufacture
If the bonnet is made removable for assembly, then ease of manufacture is improved, but device complexity increases
Solution Approach 1:
The valve body is segmented into a main body and a separate bonnet that can be independently manufactured and then assembled. The bonnet contains the bore and shoulder features, while the main body contains the valve seat. This segmentation allows each component to be optimized and manufactured separately, improving ease of manufacture while the simple coupling interface minimizes added complexity.
Data Source
AI summary
A process control valve can include a valve body having a fluid inlet, a fluid outlet and a valve seat disposed fluidically between the fluid inlet and the fluid outlet; a valve stem having a longitudinal axis, a first end and a second end longitudinally opposite the first end; and a valve member disposed within the valve body and configured to selectively sealingly engage the valve seat for controlling fluid flow through the valve. The first end of the valve stem can be disposed at least partially within the valve body and can be operably coupled to the valve member for controlling a position of the valve member relative to the valve seat. The valve member can be configured to resist blowout of the valve stem.