Bidirectional Excess Flow Valve With Dual Shutoff Assembly
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Solution Overview
Problem
Existing excess flow valves are unidirectional, limiting their application in scenarios requiring bidirectional fluid flow and posing challenges in manufacturing and integration into diverse fluid transport systems.
Innovation Solution
A bidirectional excess flow valve design featuring a housing with a valve seat and two shutoff elements, each biased open by springs, that closes when flow exceeds predetermined levels in either direction, utilizing a clasping mechanism and ethylene co-polymer-based material for high-temperature closure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If unidirectional valve design is used, then manufacturing is simpler, but bidirectional flow capability is lost
Solution Approach 1:
The valve is divided into two identical shutoff elements (first and second shutoff elements) that can independently seal against the valve seat from opposite directions. Each shutoff element functions as an independent unidirectional sealing unit, but together they provide bidirectional flow control capability.
Solution Approach 2:
The first and second shutoff elements are designed with identical structures and functions, allowing the same component design to perform sealing in both flow directions. This universal design enables the valve to handle bidirectional flow with a single, standardized component type.
2Adaptability or versatility
If bidirectional shutoff elements are added, then bidirectional flow control is achieved, but device complexity increases
Solution Approach 1:
The first and second shutoff elements are connected together through a clasping mechanism that integrates them into a single movable assembly. This merging allows both sealing elements to be actuated simultaneously by the same fluid pressure differential, reducing the need for separate actuation mechanisms.
Solution Approach 2:
The valve utilizes the excess fluid pressure itself to actuate the shutoff elements. When flow exceeds the predetermined level in either direction, the pressure differential automatically pushes the appropriate shutoff element against the valve seat, eliminating the need for external sensors, actuators, or control systems.
3Ease of manufacture
If clasping mechanism is used to connect shutoff elements, then assembly is simplified, but manufacturing precision requirements increase
Solution Approach 1:
The clasping mechanism incorporates deflectable arms that can elastically deform during the snap-fit assembly process. This flexibility allows the arms to bend and accommodate minor misalignments between mating parts, enabling assembly without extremely tight tolerances while still achieving a secure mechanical connection.
Solution Approach 2:
The distal ends of the deflectable arms are formed with curved or rounded features that facilitate smooth engagement with corresponding features on the shutoff elements. This curvature allows for gradual alignment and reduces stress concentrations during the snap-fit process.
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
Ensures safety and operational efficiency by automatically stopping fluid flow in both directions, facilitating seamless integration and cost-effective manufacturing, with components designed for easy assembly and high-temperature closure.
Implementation Method 1
a first spring extending between the valve seat assembly and the first shutoff element to bias the first shutoff element in the open position, and a second spring extending between the valve seat assembly and the second shutoff element to bias the second shutoff element in the open position
Implementation Method 2
The valve seat may be formed of an ethylene co-polymer-based material that expands at high temperature to close the fluid passageway
Data Source
AI summary
An excess flow valve is disclosed for interrupting fluid flow when a predetermined rate is exceeded. The valve includes a housing defining a passageway between first and second openings and a valve seat disposed therein. The valve seat defines a central opening with an interior sealing surface. A shutoff element is mounted within the passageway and is movable along a flow axis between an open position, permitting flow through the central opening, and a closed position, sealing against the interior surface to block flow. A biasing element urges the shutoff element toward the open position during normal operation. When differential pressure across the valve surpasses a threshold, the shutoff element is driven into sealing engagement with the valve seat. In some embodiments, guiding arms extend from the shutoff element to maintain alignment, and the valve seat may comprise a thermally responsive polymer that expands under heat to further restrict flow.