Pressure-Energized Probe Seal for Subsea Hydraulic Coupling
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Solution Overview
Problem
High-pressure, high-temperature hydraulic coupling members for subsea oil and gas applications face challenges in maintaining effective seals under varying pressure conditions, particularly during probe withdrawal, where radial movement and implosion risks are high due to vacuum or low pressure.
Innovation Solution
The introduction of a probe seal with circumferential pressure-energized seals and an annular cavity that utilizes hydraulic fluid pressure to exert radial forces on sealing elements, providing a dovetail interlocking fit and resisting inward radial movement, and employing a pressure differential to enhance sealing effectiveness and prevent implosion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional seals with dovetail interlocking fit are used in high-pressure hydraulic coupling members, then the seals can prevent radial movement during normal operation, but the seals are susceptible to implosion and radial movement during probe withdrawal due to vacuum or low pressure conditions
Solution Approach 1:
The patent converts the harmful effect of pressure differential (which causes seal implosion) into a beneficial force by directing it against the seal's outer diameter. The seal cartridge design captures the pressure differential and redirects it to press the seal outward against the probe, transforming the implosion risk into an enhanced sealing mechanism that actively prevents leakage during probe withdrawal
Solution Approach 2:
The sealing system is segmented into multiple functional components: the seal element itself, the seal cartridge with integrated pressure differential capture features, and the seal retainer with dovetail interlocking. This segmentation allows each component to address specific aspects of the sealing challenge, with the cartridge handling pressure management and the retainer handling radial position control
2Reliability
If radial passageways are implemented to balance pressure between male and female members, then fluid pressure is distributed radially, but the complexity of the coupling structure increases
Solution Approach 1:
The patent merges the pressure balancing function with the seal retainer structure by integrating radial passageways directly into the retainer component. This consolidation eliminates the need for separate pressure balancing mechanisms while maintaining the dovetail interlocking fit, thereby achieving pressure balance without proportionally increasing overall structural complexity
Solution Approach 2:
The seal cartridge acts as an intermediary component that mediates between the pressure differential forces and the seal element. It captures and redirects the pressure forces, serving as a buffer that protects the seal from direct implosion while maintaining sealing effectiveness under varying pressure conditions
3Productivity
If stepped internal bore dimensions are used to increase flow rate, then the coupling allows higher flow rates without increasing size or weight, but the manufacturing precision requirements increase
Solution Approach 1:
The patent applies local quality by providing radial sealing surfaces at specific locations within the seal cartridge rather than requiring precision throughout the entire bore. The sealing surfaces are localized to where contact with the probe occurs, allowing less critical areas to have broader tolerances while maintaining high flow capacity through the stepped bore configuration
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 significantly increases the sealing effectiveness by using pressure differentials to maintain radial force on sealing elements, preventing implosion and ensuring reliable sealing even under negative pressure conditions, thus enhancing the reliability and longevity of the seals in high-pressure subsea environments.
Implementation Method 1
Hydraulic fluid, under pressure, enters the annular cavity through the opening and exerts a radial force on the sealing elements
Implementation Method 2
In some embodiments, a pressure differential is also used to impart an inwardly-directed radial force to the crown seal
Data Source
AI summary
A crown-type probe seal for a female hydraulic coupling member has one or more pressure-energized seals for sealing between the probe seal and the body of the coupling member which retains the probe seal. The generally ring-shaped probe seal has one or more annular fluid chambers in the wall of the seal's body. Each annular fluid chamber is open to the outer circumference of the probe seal. Hydraulic fluid under pressure may enter an annular fluid chamber through its opening an exert a generally radial force as a result of a pressure differential. This radial force can act to increase the sealing effectiveness of the probe seal both to the body of the coupling member retaining the probe seal and to the probe of a male coupling member inserted in the receiving chamber of the female member.