Subsea Shut-Off Valve Crank Mechanism for Secure Deepwater Positioning
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Solution Overview
Problem
Existing subsea shut-off devices face challenges in achieving high safety and reliability while maintaining low complexity and power consumption, especially under high pressure conditions found in deep water oil or gas production systems.
Innovation Solution
A subsea shut-off device with a waterproof, oil-filled housing and a crank mechanism operated by a rotary actuator, which includes a crank, push rod, and link rod, with end stops and dead centers to ensure predictable valve operation between 'open' and 'closed' states, preventing self-actuation and maintaining secure positions without energy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a rotary actuator with crank mechanism is used to operate the valve, then the valve operation reliability is improved, but the device complexity increases
Solution Approach 1:
The actuator is divided into functional modules: rotary actuator, crank mechanism, push rod, and gate valve. Each component has a specific function, allowing independent optimization and simplifying the overall system design while maintaining reliability.
Solution Approach 2:
Instead of using complex hydraulic or electronic valve control systems, the patent employs a simple mechanical crank mechanism that converts rotational motion to linear motion, achieving reliable valve operation through mechanical advantage rather than complex control systems.
2Stress or pressure
If the housing is made robust to withstand high depth pressure, then the pressure resistance is improved, but the device complexity and weight increase
Solution Approach 1:
The housing is designed as a pressure-compensated vessel filled with oil. The flexible oil-filled design allows the housing to slightly deform under pressure, equalizing internal and external pressures and eliminating the need for extremely thick or complex structural reinforcements.
Solution Approach 2:
The patent changes the physical state of the housing interior by filling it with oil, transforming it from a rigid sealed chamber to a pressure-responsive system. This parameter change allows the housing to adapt to depth pressure dynamically rather than requiring static over-engineering.
3Manufacturing precision
If end stops and dead centers are implemented in the crank mechanism, then the valve position control precision is improved, but the device complexity increases
Solution Approach 1:
The crank mechanism includes dead centers and end stops that automatically define the valve's open and closed positions. The mechanism self-regulates its motion limits through these mechanical features, eliminating the need for external sensors or control systems to determine valve position.
Solution Approach 2:
Instead of using electronic sensors, motors, or control systems to achieve precise valve positioning, the patent replaces these with purely mechanical features (dead centers and end stops) that physically limit and define the crank's rotation range, achieving precision through mechanical geometry.
4Reliability
If the crank is configured not to perform complete rotation, then the valve state predictability is improved, but the device complexity increases
Solution Approach 1:
The crank mechanism is designed with asymmetric features including end stops positioned at specific angles that prevent complete rotation. This asymmetric configuration ensures the crank operates within a defined angular range, making the valve state predictable while using simple mechanical constraints rather than complex control logic.
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 provides a reliable, safe, and robust subsea shut-off device capable of withstanding high pressures, ensuring the valve remains securely in 'open' or 'closed' states, even under extreme depths, thus ensuring reliable fluid control in oil or gas production systems.
Implementation Method 1
Slight deformation of the housing increases the pressure of the practically incompressible oil. The resulting counterpressure protects the housing from the high depth pressure.
Data Source
Figure 1~2
Figure 3
AI summary
Submarine shut-off device, particularly for use in water depths of more than 30 m, for actuating a valve (10) with a gate valve (11), with a watertight, oil-filled housing (1), a crank mechanism (20) arranged in the housing (1), and a rotary actuator (30); wherein the rotary actuator (30) is configured to actuate a gate valve (11) of a valve (10) via the crank mechanism (20).