Subsurface Safety Valve Seal Ring for Uniform Flapper Loading
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Solution Overview
Problem
Conventional resilient seals in subsurface safety valves face performance issues at high temperatures and pressures due to compression, leading to wear and erosion, necessitating a design that maintains consistent contact.
Innovation Solution
A flapper valve assembly with a dovetail groove in the valve seat and a resilient seal ring, such as an o-ring, that maintains uniform pressure and contact, enhancing both the metal-to-metal and resilient seals' performance by optimizing the bearing area and load distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional resilient seals are used in subsurface safety valves, then the seal can be compressed to form a seal, but at high temperatures and pressures the seal becomes highly compressed exposing the metal-metal seal to wearing and eroding forces
Solution Approach 1:
A resilient seal ring is introduced as an intermediary element between the flapper and valve seat. The seal ring comprises a resilient material that maintains sealing contact under high temperature and pressure conditions, preventing direct metal-to-metal contact and thereby eliminating wear and erosion of the metal seal surfaces.
Solution Approach 2:
The sealing system uses a composite approach combining a resilient material (such as elastomer or polymer) with metal components. The resilient seal ring material is selected to withstand high temperatures and pressures while maintaining elasticity, creating a composite sealing system that leverages the advantages of both material types.
2Force
If the resilient seal is highly compressed at high temperatures and pressures, then sealing force is increased, but the metal-metal seal is exposed to wearing and eroding forces
Solution Approach 1:
The resilient seal ring acts as a mediator that absorbs and distributes the compressive sealing force. The resilient material deforms under compression to maintain sealing pressure while preventing direct force transmission between metal surfaces, thereby protecting the metal seal from wear and erosion.
Solution Approach 2:
The sealing mechanism transitions from direct metal-to-metal contact to resilient material contact. The resilient material's physical properties (elasticity, compressibility) are utilized to maintain sealing force while changing the nature of the contact interface, thereby reducing mechanical wear on metal components.
3Reliability
If a dovetail groove with seal ring is used, then uniform pressure distribution is achieved, but the device complexity increases
Solution Approach 1:
The valve seat is segmented by introducing a dovetail groove that houses the seal ring. This segmentation allows the seal ring to be positioned and retained in a specific location, ensuring uniform pressure distribution across the sealing interface while maintaining a relatively simple overall valve structure.
Solution Approach 2:
The dovetail groove is configured with curved surfaces that conform to the spherical geometry of the valve seat. This curvature ensures even distribution of pressure around the seal ring, maintaining consistent contact between the flapper, seal ring, and valve seat throughout the sealing operation.
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 improves the reliability and performance of the flapper valve assembly by maintaining consistent contact and sealing effectiveness across a wide temperature range, reducing engineering development time and total cost of ownership while increasing debris tolerance.
Implementation Method 1
A flapper valve assembly with a dovetail groove in the valve seat and a resilient seal ring, such as an o-ring, that maintains uniform pressure and contact
Data Source
AI summary
A subsurface safety valve assembly that includes a valve housing comprising a valve seat with a circumference and a seat seal surface. The valve assembly also includes a flapper rotatably connected to the valve housing and comprising a flapper seal surface. The flapper is rotatable into sealing engagement with the seat seal surface in a closed position to form a circumferential surface-to-surface seal. The valve assembly also includes a dovetail groove cut into the seat seal surface or the flapper seal surface and a seal ring held within the dovetail groove and positioned to form a seal against the seal ring when the flapper is in the closed position. The seat seal surface, the flapper seal surface, the dovetail groove, and the seal ring are shaped such that the load on the seal ring is uniform around the seal ring when the flapper is in the closed position.