Duckbill Valve Spring Leg Design for Gas-Tight Sealing
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Solution Overview
Problem
Gas chromatography systems face challenges in maintaining a reliable, gas-tight seal during the insertion and removal of needles, leading to potential leakage and reduced durability of valve components.
Innovation Solution
A duckbill valve assembly incorporating a spring member with cantilevered spring legs and a radiused bend, which exerts a spring load to maintain the slit in a closed position and ensures reliable sealing, even with varying needle sizes and repeated insertions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional valve seal is used during needle insertion and removal, then the structure is simple, but gas-tight sealing reliability deteriorates due to leakage
Solution Approach 1:
The valve seal is divided into two functional parts: a duckbill valve structure with tapered sidewalls that form a slit, and a spring member with spring legs that provide sealing force. This segmentation allows each component to specialize in either sealing geometry or elastic force application, improving gas-tight reliability while maintaining manageable complexity through modular design
Solution Approach 2:
The duckbill valve utilizes flexible sidewalls that can deform elastically under spring pressure to maintain a closed slit position. The thin film nature of the sidewalls allows them to conform and seal effectively around needle perimeters during insertion, providing reliable gas-tight sealing that rigid structures cannot achieve
2Duration of action of stationary object
If a rigid seal structure is used, then manufacturing is simple, but durability deteriorates due to wear from repeated needle insertions
Solution Approach 1:
The spring member is designed with cantilevered spring legs that can dynamically adjust their position and apply continuous elastic force during repeated needle insertions and removals. This dynamic capability allows the seal to accommodate varying needle sizes and insertion forces, extending service life without requiring complex active control mechanisms
Solution Approach 2:
The spring legs are designed with specific geometric parameters (radiused bends with radii of 0.7-0.9 mm, lengths of 10-15 mm) that optimize the distribution of spring force. These parameter changes allow the seal to maintain consistent sealing pressure throughout its service life, accommodating wear and varying operational conditions without compromising durability
3Reliability
If high spring force is applied to ensure sealing, then sealing performance is improved, but valve component durability worsens due to concentrated stress
Solution Approach 1:
The spring legs incorporate radiused bends with specific radii (0.7-0.9 mm) instead of sharp corners, which distributes stress more evenly throughout the spring structure. This curvature prevents stress concentration at bend points, allowing high spring force to be applied for reliable sealing while maintaining the strength and durability of the valve components
Solution Approach 2:
The spring force is distributed across multiple spring legs positioned at different locations around the duckbill valve slit. This spatial distribution in another dimension (lateral positioning) allows the total sealing force to be divided into multiple smaller force vectors, improving sealing performance without concentrating excessive stress on any single point of the valve structure
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 provides a robust, gas-tight seal that prevents unintended leakage and extends the service life of valve components by distributing the spring force smoothly, accommodating multiple needle insertions without compromising sealing performance.
Implementation Method 1
The spring member includes a spring leg disposed laterally adjacent the first side wall. The spring leg exerts a spring load on the first sidewall, the spring load forcing the first and second sidewalls together to maintain the slit in the closed position.
Implementation Method 2
The spring leg exerts a spring load on the first sidewall, the spring load forcing the first and second sidewalls together
Data Source
AI summary
A duckbill valve assembly includes a duckbill valve and a spring member. The duckbill valve has a longitudinal axis, a lateral axis transverse to the longitudinal axis, and opposed proximal and distal ends spaced apart along the longitudinal axis. The duckbill valve defines a valve direction extending from the proximal end to the distal end. The duckbill valve includes a first port at the proximal end, and first and second opposed sidewalls. The first and second sidewalls taper inwardly toward one another in the valve direction to form a duckbill structure. The duckbill structure includes a slit proximate the distal end. The duckbill valve is transitionable from a closed position, wherein the slit is closed, and an open position, wherein the first and second sidewalls are laterally separated proximate the slit to form a second port. The spring member includes a spring leg disposed laterally adjacent the first side wall. The spring leg exerts a spring load on the first sidewall, the spring load forcing the first and second sidewalls together to maintain the slit in the closed position. The duckbill valve assembly is configured such that, when the first and second sidewalls are displaced laterally outward to open the slit, the spring leg is displaced in the valve direction and in a laterally outward direction.