Balanced Stem Safety Valve With Tethered Force Balancing
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Solution Overview
Problem
Existing valve systems used in downhole drilling and recovery operations face high operating forces due to stem thrust and gate drag, requiring large and expensive actuators, and cannot function as both balanced stem and surface safety valves effectively.
Innovation Solution
A valve system with a balancing system comprising a tether and balance member that allows the valve to operate as both a balanced stem valve and a surface safety valve, reducing stem thrust and enabling operation in two modes by translating the opening force to the balance member, which can be flexible or rigid, and adjusting the valve member diameter to facilitate closure at a predetermined pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a balanced stem valve is used to reduce stem thrust, then the operating force is reduced, but the valve cannot function as a surface safety valve that closes at a certain pressure
Solution Approach 1:
The valve system dynamically transitions between two operational states: balanced stem mode during normal operation and surface safety valve mode during emergency closure. The tether and balance member assembly dynamically adjusts its configuration based on operational requirements, enabling the valve to switch between force-reduced operation and pressure-responsive safety closure
Solution Approach 2:
The valve is designed to perform multiple functions: it operates as a balanced stem valve during normal flow control to reduce operating forces, and simultaneously functions as a surface safety valve capable of automatic closure at predetermined pressures. The tether-balance member system enables both operational modes within a single valve architecture
2Reliability
If a surface safety valve is used to close at predetermined pressure, then safety function is improved, but large and expensive actuators are required to facilitate operation
Solution Approach 1:
The balance member acts as a counterweight that offsets the stem thrust forces during normal operation. By positioning the balance member and tether to create opposing forces, the system reduces the net force required by the actuator, enabling smaller and more cost-effective actuators while maintaining safety valve functionality
Data Source
AI summary
Embodiments of the present disclosure include a system for controlling a fluid flow. The system includes a valve body including a bore extending along an axis, an inlet, and an outlet, wherein a flow passage extends transverse the axis from the inlet to the outlet, a stem extending through the bore along the axis, and a valve member coupled to the stem. The valve member is movable along the axis, via the stem, between a closed position where the valve member blocks the flow passage to an open position where the valve member does not block the flow passage. The system also includes a balancing system coupled to the valve member, the balancing system comprising a tether and a balance member, wherein an opening force unseating the valve member is translated to the balance member.