Swing Check Valve Bushings for Low-Pressure Seat Alignment
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Solution Overview
Problem
Prior art swing check valves face misalignment issues between the flapper and valve seat due to manufacturing tolerances, leading to ineffective sealing, especially under low pressure differentials, and require larger clearances or articulating flappers which offset the centerline and increase overlap requirements.
Innovation Solution
The swing check valve design incorporates a pivot pin with ends supported in resilient bushings within the valve body, allowing the flapper to align and seal effectively even under low pressure differentials, accommodating manufacturing tolerances through flexible bushings that provide a spring force to bias the flapper into its intended position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If larger clearances are provided between the pivot pin and valve body to allow flapper alignment, then the flapper can drift to align sealing surfaces, but the sealing planes may not fully align until fluid flow reverses sufficiently to force the flapper against the valve seat
Solution Approach 1:
The patent changes the physical state of the pivot pin support from rigid to resilient by using bushings made of resilient material. This allows the pivot pin to deflect and the flapper to align with the valve seat under varying pressure conditions, ensuring reliable sealing even under low pressure differentials without requiring excessively large clearances.
Solution Approach 2:
The patent employs composite construction by combining the pivot pin with resilient bushings. The bushings are made of resilient material that provides both support and flexibility, allowing the system to accommodate manufacturing tolerances while maintaining reliable sealing performance across different operating conditions.
2Manufacturing precision
If articulating flappers with separate pivot pins are used to provide angular freedom for alignment, then the sealing plane can align with the fixed sealing plane, but the centerline of the flapper becomes offset from the centerline of the valve seat requiring larger overlap
Solution Approach 1:
The patent merges the flapper and pivot pin into a single integrally formed component. This eliminates the need for a separate articulating joint between the flapper and pivot pin, simplifying the device structure while still achieving proper alignment through the resilient bushings that support the integrated pivot pin.
Solution Approach 2:
The patent changes the support characteristics of the pivot pin from rigid to resilient by using bushings made of resilient material. This allows the integrated flapper-pivot pin component to deflect and align with the valve seat, achieving proper sealing without requiring offset centerlines or larger overlap areas.
3Strength
If rigid pivot pin support is used, then the structure is simple and strong, but manufacturing tolerance limitations prevent exact alignment between sealing surfaces
Solution Approach 1:
The patent employs composite construction by combining the rigid pivot pin with resilient bushings. The bushings are made of resilient material that provides both support and flexibility, allowing the system to accommodate manufacturing tolerances while maintaining reliable sealing performance across different operating conditions.
Solution Approach 2:
The patent changes the physical state of the pivot pin support from rigid to resilient by using bushings made of resilient material. This allows the pivot pin to deflect and the flapper to align with the valve seat under varying pressure conditions, ensuring reliable sealing even under low pressure differentials without requiring excessively large clearances.
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
This design ensures effective sealing between the flapper and valve seat under various pressure conditions, reducing misalignment issues and maintaining a proper seal without the need for excessive overlap or separate articulating components.
Implementation Method 1
The pivot pin comprises opposite first and second ends, each of which is supported in a corresponding resilient bushing which is supported in the valve body
Implementation Method 2
accommodating manufacturing tolerances through flexible bushings that provide a spring force to bias the flapper into its intended position
Data Source
AI summary
A check valve which includes a valve body having an inlet end, an outlet end and a flow bore that extends between the inlet and outlet ends; a valve seat which is positioned across the flow bore; and a flapper which is configured to seal against the valve seat. The flapper is connected to or formed integrally with a pivot pin and is pivotable between a closed position in which the flapper is positioned against the valve seat and an open position in which the flapper is displaced from the valve seat. The pivot pin has opposite first and second ends, each of which is supported in a corresponding resilient bushing which is supported in the valve body. The resilient bushings allow the flapper to better align with the valve seat when the flapper is in the closed position.