Subsea Coupling Relief Channels Prevent Hydraulic Lock
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Solution Overview
Problem
Subsea couplings face challenges with high makeup forces and hydraulic fluid entrapment due to susceptibility to pressure changes, leading to potential hydraulic lock and seal deformation during the mating process.
Innovation Solution
The design incorporates a male and female coupler with a recess and annular seal, featuring relief channels to allow trapped hydraulic fluid to escape, and a member to retain the C-seal or O-ring seal, enabling it to change shape and alleviate pressure, ensuring effective radial sealing and preventing hydraulic lock during coupling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an annular seal is used to provide radial sealing between the probe and socket, then sealing effectiveness is improved, but hydraulic fluid entrapment occurs leading to high makeup forces
Solution Approach 1:
The socket is segmented into multiple chambers by partition walls, with each chamber containing a separate annular seal. Relief channels are provided in each chamber to allow trapped hydraulic fluid to escape during make-up, preventing hydraulic lock while maintaining effective sealing at each segment
Solution Approach 2:
Relief channels act as intermediary pathways that allow trapped hydraulic fluid to escape from the seal chambers during make-up. These channels provide a controlled escape route for the fluid, preventing pressure buildup that would otherwise create high makeup forces
2Stability of the object's composition
If the C-seal is retained firmly in the recess, then seal position stability is improved, but the seal cannot change shape to allow trapped fluid egress
Solution Approach 1:
The C-seal is retained firmly at its base in the recess to maintain position stability, while the C-section portion is allowed to change shape locally to enable trapped fluid egress. This localized flexibility resolves the contradiction between firm retention and shape change capability
3Reliability
If multiple seals are used to ensure redundant sealing, then sealing reliability is improved, but device complexity increases
Solution Approach 1:
The coupling is divided into multiple independent sealing chambers, each with its own annular seal and relief channels. This segmentation provides redundant sealing paths while keeping each individual seal simple and manageable, balancing reliability with complexity
Solution Approach 2:
Each sealing chamber is designed as a universal module that can be replicated. The same basic structure with annular seal and relief channels is used in each chamber, reducing overall design complexity through standardization while providing multiple sealing paths for enhanced reliability
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 effectively prevents hydraulic lock and ensures proper sealing by allowing trapped fluid to escape, facilitating smooth coupling and uncoupling while maintaining seal integrity, even under high pressure conditions.
Implementation Method 1
susceptibility to pressure changes, leading to potential hydraulic lock and seal deformation during the mating process
Implementation Method 2
at least one relief channel disposed to allow the escape of hydraulic fluid entrapped by the seal within the recess
Implementation Method 3
a member which extends into the interior of the C-section of the C-seal to retain the C-seal in the recess while allowing the C-seal to change its sectional shape and thereby to allow egress of trapped fluid
Data Source
AI summary
A subsea coupling comprises a male coupler having a probe and a female coupler comprising a socket for the reception of the probe. The couplers each include a valve which is openable on mating of the couplers to provide communication with the socket. The socket includes a recess accommodating an annular seal for providing a radial seal between the probe and the socket. In one embodiment the leading edge of the probe includes at least one relief channel for allowing the escape of hydraulic fluid entrapped between the probe, the seal and the recess when the couplers are made up. There may be a stand-off ring disposed between one end of the recess and the inner side of the seal. In another embodiment the relief channel is provided in the socket.