Conforming Check Valve Seat to Eliminate Corrosion Gaps
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Solution Overview
Problem
Existing fluid valves, particularly check valves, face premature failure due to corrosion and stress corrosion cracking in corrosive environments like offshore or subsea settings, caused by intentional physical gaps that allow ambient fluids to enter and cause damage, leading to integrity issues in fluid control circuits.
Innovation Solution
A non-gapped check valve design featuring a conforming seat ring with regions of different compressibility, eliminating the tolerance stack gap and ensuring proper assembly and sealing, thus preventing corrosion and extending the valve's lifespan.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If an intentional physical gap is present between the valve body and cover to accommodate machining tolerances, then proper assembly is ensured, but corrosion and stress corrosion cracking occur due to ambient fluid entry
Solution Approach 1:
The patent employs a flexible seal member (O-ring or elastomeric seal) that acts as a thin film barrier to prevent ambient fluid from entering the tolerance gap. The seal member is positioned within a groove in the cover, creating a barrier that blocks corrosive fluids while still allowing the cover to be properly positioned relative to the valve body despite machining variations.
Solution Approach 2:
The patent creates a protected environment by sealing the tolerance gap between the cover and valve body using a flexible seal member. This effectively isolates the internal components from the corrosive ambient atmosphere, creating an inert-like environment that prevents corrosion and stress corrosion cracking of the valve components.
2Strength
If the seat ring is made of rigid plastic material to withstand pressure, then pressure resistance is improved, but the seat ring cannot conform to machining variations causing assembly issues
Solution Approach 1:
The patent introduces a spring-loaded mechanism that allows the rigid plastic seat ring to dynamically adjust its position. The spring applies force to push the seat ring against the valve body, and this force can vary to accommodate machining tolerances while maintaining consistent contact and sealing. The seat ring can move slightly within its mounting features to achieve proper alignment.
Solution Approach 2:
The patent changes the mechanical parameters of the seat ring assembly by introducing spring force. The spring allows the seat ring position to vary within a range, transforming the rigid fixed-position seat ring into one that can adapt to machining variations. The spring force parameter can be adjusted to ensure proper contact pressure while accommodating dimensional variations.
3Reliability
If the cage is sized to bias the seat ring against the valve body, then sealing is ensured, but the tolerance stack gap cannot be eliminated
Solution Approach 1:
The patent uses a flexible seal member (thin film) positioned in a groove in the cover to seal the tolerance stack gap. This flexible barrier prevents ambient fluid from entering the gap while allowing the cage to maintain its biasing function on the seat ring. The seal member decouples the sealing of the gap from the cage positioning function.
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 non-gapped check valve design enhances corrosion resistance and extends the valve's operational life by ensuring proper assembly and sealing, reducing the risk of premature failure and maintaining the integrity of fluid control circuits in corrosive environments.
Implementation Method 1
a spring 15 extends between the cap 10 and the recessed annular seal sleeve 3 to bias the recessed annular seal sleeve 3 against the back side 13 of the seat ring 11
Implementation Method 2
The O-ring 22 contacts the base of the circumferential seal groove 21 and the counterbore inner wall 20
Data Source
AI summary
A valve includes a valve body including a first fluid, a second fluid port, and an interior passage fluidly connecting the first and second fluid ports, a bore extending inwardly of the valve body and terminating in an annular first seat securement surface extending around the interior passage, the second fluid port fluidly connected to the bore, a cage disposed in the bore, the cage having an annular second seat securement surface and an opposed first annular surface, the annular second seat securement surface facing the annular first seat securement surface, a cover extending over the first wall of the valve body and including a cage engagement surface contacting the first annular surface, and an annular seat having a main body having an opening therethrough and comprising a first annular region having a first elevation and a second annular region having a second elevation different than the first annular region.